{-# LINE 1 "Database/PostgreSQL/LibPQ.hsc" #-} ----------------------------------------------------------------------------- {-# LINE 2 "Database/PostgreSQL/LibPQ.hsc" #-} -- | -- Module : Database.PostgreSQL.LibPQ -- Copyright : (c) 2010 Grant Monroe, -- (c) 2011 Leon P Smith -- License : BSD3 -- -- Maintainer : leon@melding-monads.com -- Stability : experimental -- -- This is a binding to libpq: the C application programmer's -- interface to PostgreSQL. libpq is a set of library functions that -- allow client programs to pass queries to the PostgreSQL backend -- server and to receive the results of these queries. -- -- This is intended to be a very low-level interface to libpq. It -- provides memory management and a somewhat more consistent interface -- to error conditions. Application code should typically use a -- higher-level PostgreSQL binding. -- -- This interface is not safe, because libpq unfortunately conflates -- explicit disconnects with memory management. A use-after-free memory -- fault will result if a connection is used in any way after 'finish' is -- called. This will likely cause a segfault, or return an error if memory -- has not yet been reused. Other more bizarre behaviors are possible, -- though unlikely by chance. Higher-level bindings need to be aware of -- this issue and need to ensure that application code cannot cause the -- functions in this module to be called on an 'finish'ed connection. -- -- One possibility is to represent a connection in a higher-level interface -- as @MVar (Maybe Connection)@, using @Nothing@ to represent an explicitly -- disconnected state. This was done in an earlier incarnation of this -- library, however this was removed because a higher level binding is -- likely to use a similar construct to deal with other issues. Thus -- incorporating that in this module results in extra layers of indirection -- for relatively little functionality. -- ----------------------------------------------------------------------------- {-# LANGUAGE ForeignFunctionInterface #-} {-# LANGUAGE EmptyDataDecls #-} {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE ScopedTypeVariables #-} {-# LANGUAGE BangPatterns #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} module Database.PostgreSQL.LibPQ ( -- * Database Connection Control Functions -- $dbconn Connection , connectdb , connectStart , connectPoll , newNullConnection , isNullConnection --, conndefaults --, conninfoParse , reset , resetStart , resetPoll , PollingStatus(..) , finish -- * Connection Status Functions -- $connstatus , db , user , pass , host , port , options , ConnStatus(..) , status , TransactionStatus(..) , transactionStatus , parameterStatus , protocolVersion , serverVersion , errorMessage , socket , backendPID , connectionNeedsPassword , connectionUsedPassword --, getssl -- * Command Execution Functions -- $commandexec , Result , exec , Format(..) , Oid(..) , invalidOid , execParams , prepare , execPrepared , describePrepared , describePortal , ExecStatus(..) , resultStatus , resStatus , resultErrorMessage , FieldCode(..) , resultErrorField , unsafeFreeResult -- * Retrieving Query Result Information -- $queryresultinfo , ntuples , nfields , Row(..) , Column(..) , toRow , toColumn , fname , fnumber , ftable , ftablecol , fformat , ftype , fmod , fsize , getvalue , getvalue' , getisnull , getlength , nparams , paramtype -- Retrieving Result Information for Other Commands -- $othercommands , cmdStatus , cmdTuples , oidValue -- * Escaping Strings for Inclusion in SQL Commands , escapeStringConn -- * Escaping Binary Strings for Inclusion in SQL Commands , escapeByteaConn , unescapeBytea -- * Using COPY -- $copy , CopyInResult(..) , putCopyData , putCopyEnd , CopyOutResult(..) , getCopyData -- * Asynchronous Command Processing -- $asynccommand , sendQuery , sendQueryParams , sendPrepare , sendQueryPrepared , sendDescribePrepared , sendDescribePortal , getResult , consumeInput , isBusy , setnonblocking , isnonblocking , FlushStatus(..) , flush -- * Cancelling Queries in Progress -- $cancel , Cancel , getCancel , cancel -- * Asynchronous Notification -- $asyncnotification , Notify(..) , notifies -- * Control Functions -- $control , clientEncoding , setClientEncoding , Verbosity(..) , setErrorVerbosity -- * Large Objects -- $largeobjects , LoFd(..) , loCreat , loCreate , loImport , loImportWithOid , loExport , loOpen , loWrite , loRead , loSeek , loTell , loTruncate , loClose , loUnlink ) where {-# LINE 206 "Database/PostgreSQL/LibPQ.hsc" #-} {-# LINE 207 "Database/PostgreSQL/LibPQ.hsc" #-} import Prelude hiding ( print ) import Foreign import Foreign.C.Types import Foreign.C.String {-# LINE 213 "Database/PostgreSQL/LibPQ.hsc" #-} import qualified Foreign.ForeignPtr.Unsafe as Unsafe {-# LINE 215 "Database/PostgreSQL/LibPQ.hsc" #-} import qualified Foreign.Concurrent as FC import System.Posix.Types ( Fd(..) ) import Data.List ( foldl' ) import System.IO ( IOMode(..), SeekMode(..) ) {-# LINE 221 "Database/PostgreSQL/LibPQ.hsc" #-} import GHC.Conc ( closeFdWith ) -- Won't work with GHC 7.0.1 {-# LINE 223 "Database/PostgreSQL/LibPQ.hsc" #-} import System.Posix.Types ( CPid ) import Data.ByteString.Char8 () import qualified Data.ByteString.Unsafe as B import qualified Data.ByteString.Internal as B ( fromForeignPtr , c_strlen ) import qualified Data.ByteString as B {-# LINE 233 "Database/PostgreSQL/LibPQ.hsc" #-} import Control.Concurrent (newMVar, tryTakeMVar) {-# LINE 235 "Database/PostgreSQL/LibPQ.hsc" #-} -- $dbconn -- The following functions deal with making a connection to a -- PostgreSQL backend server. An application program can have several -- backend connections open at one time. (One reason to do that is to -- access more than one database.) Each connection is represented by a -- 'Connection', which is obtained from the function 'connectdb', or -- 'connectStart'. The 'status' function should be called to check -- whether a connection was successfully made before queries are sent -- via the connection object. -- | 'Connection' encapsulates a connection to the backend. newtype Connection = Conn (ForeignPtr PGconn) deriving Eq data PGconn -- | Makes a new connection to the database server. -- -- This function opens a new database connection using the parameters -- taken from the string conninfo. Its nonblocking analogues are -- 'connectStart' and 'connectPoll'. -- -- The passed string can be empty to use all default parameters, or it -- can contain one or more parameter settings separated by -- whitespace. Each parameter setting is in the form keyword = -- value. Spaces around the equal sign are optional. To write an empty -- value or a value containing spaces, surround it with single quotes, -- e.g., keyword = 'a value'. Single quotes and backslashes within the -- value must be escaped with a backslash, i.e., \' and \\. connectdb :: B.ByteString -- ^ Connection Info -> IO Connection connectdb conninfo = do connPtr <- B.useAsCString conninfo c_PQconnectdb if connPtr == nullPtr then fail "libpq failed to allocate a PGconn structure" {-# LINE 270 "Database/PostgreSQL/LibPQ.hsc" #-} else Conn `fmap` newForeignPtrOnce connPtr (pqfinish connPtr) {-# LINE 274 "Database/PostgreSQL/LibPQ.hsc" #-} -- | Make a connection to the database server in a nonblocking manner. connectStart :: B.ByteString -- ^ Connection Info -> IO Connection connectStart connStr = do connPtr <- B.useAsCString connStr c_PQconnectStart if connPtr == nullPtr then fail "libpq failed to allocate a PGconn structure" {-# LINE 283 "Database/PostgreSQL/LibPQ.hsc" #-} else Conn `fmap` newForeignPtrOnce connPtr (pqfinish connPtr) {-# LINE 287 "Database/PostgreSQL/LibPQ.hsc" #-} {-# LINE 289 "Database/PostgreSQL/LibPQ.hsc" #-} pqfinish :: Ptr PGconn -> IO () pqfinish conn = do mfd <- c_PQsocket conn case mfd of -1 -> -- This can happen if the connection is bad/lost -- This case may be worth investigating further c_PQfinish conn fd -> closeFdWith (\_ -> c_PQfinish conn) (Fd fd) -- | Workaround for bug in 'FC.newForeignPtr' before base 4.6. Ensure the -- finalizer is only run once, to prevent a segfault. See GHC ticket #7170 -- -- Note that 'getvalue' and 'maybeBsFromForeignPtr' do not need this -- workaround, since their finalizers are just 'touchForeignPtr' calls. newForeignPtrOnce :: Ptr a -> IO () -> IO (ForeignPtr a) newForeignPtrOnce ptr fin = do mv <- newMVar fin FC.newForeignPtr ptr $ tryTakeMVar mv >>= maybe (return ()) id {-# LINE 308 "Database/PostgreSQL/LibPQ.hsc" #-} -- | Allocate a Null Connection, which all libpq functions -- should safely fail on. newNullConnection :: IO Connection newNullConnection = Conn `fmap` newForeignPtr_ nullPtr -- | Test if a connection is the Null Connection. isNullConnection :: Connection -> Bool {-# LINE 317 "Database/PostgreSQL/LibPQ.hsc" #-} isNullConnection (Conn x) = Unsafe.unsafeForeignPtrToPtr x == nullPtr {-# LINE 321 "Database/PostgreSQL/LibPQ.hsc" #-} {-# INLINE isNullConnection #-} -- | If 'connectStart' succeeds, the next stage is to poll libpq so -- that it can proceed with the connection sequence. Use 'socket' to -- obtain the 'Fd' of the socket underlying the database -- connection. Loop thus: If 'connectPoll' last returned -- 'PollingReading', wait until the socket is ready to read (as -- indicated by select(), poll(), or similar system function). Then -- call 'connectPoll' again. Conversely, if 'connectPoll' last -- returned 'PollingWriting', wait until the socket is ready to write, -- then call 'connectPoll' again. If you have yet to call -- 'connectPoll', i.e., just after the call to 'connectStart', behave -- as if it last returned 'PollingWriting'. Continue this loop until -- 'connectPoll' returns 'PollingFailed', indicating the connection -- procedure has failed, or 'PollingOk', indicating the connection has -- been successfully made. connectPoll :: Connection -> IO PollingStatus connectPoll = pollHelper c_PQconnectPoll -- PQconndefaults -- Returns the default connection options. -- PQconninfoOption *PQconndefaults(void); -- typedef struct -- { -- char *keyword; /* The keyword of the option */ -- char *envvar; /* Fallback environment variable name */ -- char *compiled; /* Fallback compiled in default value */ -- char *val; /* Option's current value, or NULL */ -- char *label; /* Label for field in connect dialog */ -- char *dispchar; /* Indicates how to display this field -- in a connect dialog. Values are: -- "" Display entered value as is -- "*" Password field - hide value -- "D" Debug option - don't show by default */ -- int dispsize; /* Field size in characters for dialog */ -- } PQconninfoOption; -- Returns a connection options array. This can be used to determine all possible PQconnectdb options and their current default values. The return value points to an array of PQconninfoOption structures, which ends with an entry having a null keyword pointer. The null pointer is returned if memory could not be allocated. Note that the current default values (val fields) will depend on environment variables and other context. Callers must treat the connection options data as read-only. -- After processing the options array, free it by passing it to PQconninfoFree. If this is not done, a small amount of memory is leaked for each call to PQconndefaults. -- PQconninfoParse -- Returns parsed connection options from the provided connection string. -- PQconninfoOption *PQconninfoParse(const char *conninfo, char **errmsg); -- Parses a connection string and returns the resulting options as an array; or returns NULL if there is a problem with the connection string. This can be used to determine the PQconnectdb options in the provided connection string. The return value points to an array of PQconninfoOption structures, which ends with an entry having a null keyword pointer. -- Note that only options explicitly specified in the string will have values set in the result array; no defaults are inserted. -- If errmsg is not NULL, then *errmsg is set to NULL on success, else to a malloc'd error string explaining the problem. (It is also possible for *errmsg to be set to NULL even when NULL is returned; this indicates an out-of-memory situation.) -- After processing the options array, free it by passing it to PQconninfoFree. If this is not done, some memory is leaked for each call to PQconninfoParse. Conversely, if an error occurs and errmsg is not NULL, be sure to free the error string using PQfreemem. -- | Resets the communication channel to the server. -- -- This function will close the connection to the server and attempt -- to reestablish a new connection to the same server, using all the -- same parameters previously used. This might be useful for error -- recovery if a working connection is lost. reset :: Connection -> IO () reset connection = withConn connection c_PQreset -- | Reset the communication channel to the server, in a nonblocking manner. resetStart :: Connection -> IO Bool resetStart connection = enumFromConn connection c_PQresetStart -- | To initiate a connection reset, call 'resetStart'. If it returns -- 'False', the reset has failed. If it returns 'True', poll the reset -- using 'resetPoll' in exactly the same way as you would create the -- connection using 'connectPoll'. resetPoll :: Connection -> IO PollingStatus resetPoll = pollHelper c_PQresetPoll data PollingStatus = PollingFailed | PollingReading | PollingWriting | PollingOk deriving (Eq, Show) pollHelper :: (Ptr PGconn -> IO CInt) -> Connection -> IO PollingStatus pollHelper poller connection = do code <- withConn connection poller case code of (1) -> return PollingReading {-# LINE 417 "Database/PostgreSQL/LibPQ.hsc" #-} (3) -> return PollingOk {-# LINE 418 "Database/PostgreSQL/LibPQ.hsc" #-} (2) -> return PollingWriting {-# LINE 419 "Database/PostgreSQL/LibPQ.hsc" #-} (0) -> return PollingFailed {-# LINE 420 "Database/PostgreSQL/LibPQ.hsc" #-} _ -> error $ "unexpected polling status " ++ show code -- | Closes the connection to the server. -- -- Note that the 'Connection' must not be used again after 'finish' -- has been called. finish :: Connection -> IO () finish (Conn fp) = do finalizeForeignPtr fp -- $connstatus -- These functions can be used to interrogate the status of an -- existing database connection object. -- | Returns the database name of the connection. db :: Connection -> IO (Maybe B.ByteString) db = statusString c_PQdb -- | Returns the user name of the connection. user :: Connection -> IO (Maybe B.ByteString) user = statusString c_PQuser -- | Returns the password of the connection. pass :: Connection -> IO (Maybe B.ByteString) pass = statusString c_PQpass -- | Returns the server host name of the connection. host :: Connection -> IO (Maybe B.ByteString) host = statusString c_PQhost -- | Returns the port of the connection. port :: Connection -> IO (Maybe B.ByteString) port = statusString c_PQport -- | Returns the command-line options passed in the connection request. options :: Connection -> IO (Maybe B.ByteString) options = statusString c_PQoptions -- | Helper function that checks for nullPtrs and returns the empty -- string. statusString :: (Ptr PGconn -> IO CString) -> Connection -> IO (Maybe B.ByteString) statusString f connection = withConn connection $ \ptr -> do cstr <- f ptr if cstr == nullPtr then return Nothing else Just `fmap` B.packCString cstr data ConnStatus = ConnectionOk -- ^ The 'Connection' is ready. | ConnectionBad -- ^ The connection procedure has failed. | ConnectionStarted -- ^ Waiting for connection to be made. | ConnectionMade -- ^ Connection OK; waiting to send. | ConnectionAwaitingResponse -- ^ Waiting for a response from the server. | ConnectionAuthOk -- ^ Received authentication; -- waiting for backend start-up to -- finish. | ConnectionSetEnv -- ^ Negotiating environment-driven -- parameter settings. | ConnectionSSLStartup -- ^ Negotiating SSL encryption. deriving (Eq, Show) -- | Returns the status of the connection. -- -- The status can be one of a number of values. However, only two of -- these are seen outside of an asynchronous connection procedure: -- 'ConnectionOk' and 'ConnectionBad'. A good connection to the -- database has the status 'ConnectionOk'. A failed connection attempt -- is signaled by status 'ConnectionBad'. Ordinarily, an OK status -- will remain so until 'finish', but a communications failure might -- result in the status changing to 'ConnectionBad' prematurely. In -- that case the application could try to recover by calling 'reset'. -- -- See the entry for 'connectStart' and 'connectPoll' with regards to -- other status codes that might be seen. status :: Connection -> IO ConnStatus status connection = do stat <- withConn connection c_PQstatus return $ case stat of (0) -> ConnectionOk {-# LINE 521 "Database/PostgreSQL/LibPQ.hsc" #-} (1) -> ConnectionBad {-# LINE 522 "Database/PostgreSQL/LibPQ.hsc" #-} (2) -> ConnectionStarted {-# LINE 523 "Database/PostgreSQL/LibPQ.hsc" #-} (3) -> ConnectionMade {-# LINE 524 "Database/PostgreSQL/LibPQ.hsc" #-} (4)-> ConnectionAwaitingResponse {-# LINE 525 "Database/PostgreSQL/LibPQ.hsc" #-} (5) -> ConnectionAuthOk {-# LINE 526 "Database/PostgreSQL/LibPQ.hsc" #-} (6) -> ConnectionSetEnv {-# LINE 527 "Database/PostgreSQL/LibPQ.hsc" #-} (7) -> ConnectionSSLStartup {-# LINE 528 "Database/PostgreSQL/LibPQ.hsc" #-} --(#const CONNECTION_NEEDED) -> ConnectionNeeded c -> error $ "Unknown connection status " ++ show c data TransactionStatus = TransIdle -- ^ currently idle | TransActive -- ^ a command is in progress | TransInTrans -- ^ idle, in a valid transaction block | TransInError -- ^ idle, in a failed transaction block | TransUnknown -- ^ the connection is bad deriving (Eq, Show) -- | Returns the current in-transaction status of the server. -- -- 'TransActive' is reported only when a query has been sent to the -- server and not yet completed. transactionStatus :: Connection -> IO TransactionStatus transactionStatus connection = do stat <- withConn connection c_PQtransactionStatus return $ case stat of (0) -> TransIdle {-# LINE 549 "Database/PostgreSQL/LibPQ.hsc" #-} (1) -> TransActive {-# LINE 550 "Database/PostgreSQL/LibPQ.hsc" #-} (2) -> TransInTrans {-# LINE 551 "Database/PostgreSQL/LibPQ.hsc" #-} (3) -> TransInError {-# LINE 552 "Database/PostgreSQL/LibPQ.hsc" #-} (4) -> TransUnknown {-# LINE 553 "Database/PostgreSQL/LibPQ.hsc" #-} c -> error $ "Unknown transaction status " ++ show c -- | Looks up a current parameter setting of the server. -- -- Certain parameter values are reported by the server automatically -- at connection startup or whenever their values -- change. 'parameterStatus' can be used to interrogate these -- settings. It returns the current value of a parameter if known, or -- 'Nothing' if the parameter is not known. parameterStatus :: Connection -> B.ByteString -- ^ paramName -> IO (Maybe B.ByteString) parameterStatus connection paramName = withConn connection $ \connPtr -> B.useAsCString paramName $ \paramNamePtr -> do cstr <- c_PQparameterStatus connPtr paramNamePtr if cstr == nullPtr then return Nothing else Just `fmap` B.packCString cstr -- | Interrogates the frontend/backend protocol being used. -- -- Applications might wish to use this to determine whether certain -- features are supported. Currently, the possible values are 2 (2.0 -- protocol), 3 (3.0 protocol), or zero (connection bad). This will -- not change after connection startup is complete, but it could -- theoretically change during a connection reset. The 3.0 protocol -- will normally be used when communicating with PostgreSQL 7.4 or -- later servers; pre-7.4 servers support only protocol 2.0. (Protocol -- 1.0 is obsolete and not supported by libpq.) protocolVersion :: Connection -> IO Int protocolVersion connection = fmap fromIntegral $ withConn connection c_PQprotocolVersion -- | Returns an integer representing the backend version. -- -- Applications might use this to determine the version of the -- database server they are connected to. The number is formed by -- converting the major, minor, and revision numbers into -- two-decimal-digit numbers and appending them together. For example, -- version 8.1.5 will be returned as 80105, and version 8.2 will be -- returned as 80200 (leading zeroes are not shown). Zero is returned -- if the connection is bad. serverVersion :: Connection -> IO Int serverVersion connection = fmap fromIntegral $ withConn connection c_PQserverVersion -- | Returns the error message most recently generated by an operation -- on the connection. -- -- Nearly all libpq functions will set a message for 'errorMessage' if -- they fail. Note that by libpq convention, a nonempty 'errorMessage' -- result can be multiple lines, and will include a trailing -- newline. The result string should not be expected to remain the -- same across operations on the 'Connection'. errorMessage :: Connection -> IO (Maybe B.ByteString) errorMessage conn = withConn conn $ \cptr -> do strptr <- c_PQerrorMessage cptr if strptr == nullPtr then return Nothing else Just `fmap` B.packCString strptr -- | Obtains the file descriptor number of the connection socket to -- the server. (This will not change during normal operation, but -- could change during connection setup or reset.) socket :: Connection -> IO (Maybe Fd) socket connection = do cFd <- withConn connection c_PQsocket return $ case cFd of -1 -> Nothing _ -> Just $ Fd cFd -- | Returns the process 'CPid' of the backend server process -- handling this connection. -- -- The backend PID is useful for debugging purposes and for comparison -- to NOTIFY messages (which include the PID of the notifying backend -- process). Note that the PID belongs to a process executing on the -- database server host, not the local host! backendPID :: Connection -> IO CPid backendPID connection = fmap fromIntegral $ withConn connection c_PQbackendPID -- | Returns 'True' if the connection authentication method required a -- password, but none was available. Returns 'False' if not. -- -- This function can be applied after a failed connection attempt to -- decide whether to prompt the user for a password. connectionNeedsPassword :: Connection -> IO Bool connectionNeedsPassword connection = enumFromConn connection c_PQconnectionNeedsPassword -- | Returns 'True' if the connection authentication method used a -- password. Returns 'False' if not. -- -- This function can be applied after either a failed or successful -- connection attempt to detect whether the server demanded a -- password. connectionUsedPassword :: Connection -> IO Bool connectionUsedPassword connection = enumFromConn connection c_PQconnectionUsedPassword -- TODO: getSSL :: Connection -> IO SSL -- $commandexec -- Once a connection to a database server has been successfully -- established, the functions described here are used to perform SQL -- queries and commands. -- | 'Result' encapsulates the result of a query (or more precisely, -- of a single SQL command --- a query string given to 'sendQuery' can -- contain multiple commands and thus return multiple instances of -- 'Result'. newtype Result = Result (ForeignPtr PGresult) deriving (Eq, Show) data PGresult data Format = Text | Binary deriving (Eq, Ord, Show, Enum) newtype Oid = Oid CUInt deriving (Eq, Ord, Read, Show, Storable) invalidOid :: Oid invalidOid = Oid (0) {-# LINE 691 "Database/PostgreSQL/LibPQ.hsc" #-} -- | Submits a command to the server and waits for the result. -- -- Returns a 'Result' or possibly 'Nothing'. A 'Result' will generally -- be returned except in out-of-memory conditions or serious errors -- such as inability to send the command to the server. If a 'Nothing' -- is returned, it should be treated like a 'FatalError' result. Use -- 'errorMessage' to get more information about such errors. -- -- It is allowed to include multiple SQL commands (separated by -- semicolons) in the command string. Multiple queries sent in a -- single 'exec' call are processed in a single transaction, unless -- there are explicit BEGIN/COMMIT commands included in the query -- string to divide it into multiple transactions. Note however that -- the returned 'Result' structure describes only the result of the -- last command executed from the string. Should one of the commands -- fail, processing of the string stops with it and the returned -- 'Result' describes the error condition. exec :: Connection -- ^ connection -> B.ByteString -- ^ statement -> IO (Maybe Result) -- ^ result exec connection query = resultFromConn connection $ \p -> B.useAsCString query $ c_PQexec p -- | Submits a command to the server and waits for the result, with -- the ability to pass parameters separately from the SQL command -- text. -- -- 'execParams' is like 'exec', but offers additional functionality: -- parameter values can be specified separately from the command -- string proper, and query results can be requested in either text or -- binary format. 'execParams' is supported only in protocol 3.0 and -- later connections; it will fail when using protocol 2.0. -- -- The primary advantage of 'execParams' over 'exec' is that parameter -- values can be separated from the command string, thus avoiding the -- need for tedious and error-prone quoting and escaping. -- -- Unlike 'exec', 'execParams' allows at most one SQL command in the -- given string. (There can be semicolons in it, but not more than one -- nonempty command.) This is a limitation of the underlying protocol, -- but has some usefulness as an extra defense against SQL-injection -- attacks. -- -- Tip: Specifying parameter types via OIDs is tedious, particularly -- if you prefer not to hard-wire particular OID values into your -- program. However, you can avoid doing so even in cases where the -- server by itself cannot determine the type of the parameter, or -- chooses a different type than you want. In the SQL command text, -- attach an explicit cast to the parameter symbol to show what data -- type you will send. For example: -- SELECT * FROM mytable WHERE x = $1::bigint; -- This forces parameter $1 to be treated as bigint, whereas by -- default it would be assigned the same type as x. Forcing the -- parameter type decision, either this way or by specifying a numeric -- type OID, is strongly recommended when sending parameter values in -- binary format, because binary format has less redundancy than text -- format and so there is less chance that the server will detect a -- type mismatch mistake for you. execParams :: Connection -- ^ connection -> B.ByteString -- ^ statement -> [Maybe (Oid, B.ByteString, Format)] -- ^ parameters -> Format -- ^ result format -> IO (Maybe Result) -- ^ result execParams connection statement params rFmt = do let (oids, values, lengths, formats) = foldl' accum ([],[],[],[]) $ reverse params c_lengths = map toEnum lengths :: [CInt] n = toEnum $ length params f = toEnum $ fromEnum rFmt resultFromConn connection $ \c -> B.useAsCString statement $ \s -> withArray oids $ \ts -> withMany (maybeWith B.useAsCString) values $ \c_values -> withArray c_values $ \vs -> withArray c_lengths $ \ls -> withArray formats $ \fs -> c_PQexecParams c s n ts vs ls fs f where accum (!a,!b,!c,!d) Nothing = ( invalidOid:a , Nothing:b , 0:c , 0:d ) accum (!a,!b,!c,!d) (Just (t,v,f)) = ( t:a , (Just v):b , (B.length v):c , (toEnum $ fromEnum f):d ) -- | Submits a request to create a prepared statement with the given -- parameters, and waits for completion. -- -- 'prepare' creates a prepared statement for later execution with -- 'execPrepared'. This feature allows commands that will be used -- repeatedly to be parsed and planned just once, rather than each -- time they are executed. 'prepare' is supported only in protocol 3.0 -- and later connections; it will fail when using protocol 2.0. -- -- The function creates a prepared statement named stmtName from the -- query string, which must contain a single SQL command. stmtName can -- be \"\" to create an unnamed statement, in which case any -- pre-existing unnamed statement is automatically replaced; otherwise -- it is an error if the statement name is already defined in the -- current session. If any parameters are used, they are referred to -- in the query as $1, $2, etc. paramTypes specifies, by 'Oid', the -- data types to be assigned to the parameter symbols. If paramTypes -- is 'Nothing', or any particular element in the array is zero, the -- server assigns a data type to the parameter symbol in the same way -- it would do for an untyped literal string. Also, the query can use -- parameter symbols with numbers higher than the length of -- paramTypes; data types will be inferred for these symbols as -- well. (See 'describePrepared' for a means to find out what data -- types were inferred.) -- -- As with 'exec', the result is normally a 'Result' whose contents -- indicate server-side success or failure. A 'Nothing' result -- indicates out-of-memory or inability to send the command at -- all. Use 'errorMessage' to get more information about such errors. -- -- Prepared statements for use with 'execPrepared' can also be created -- by executing SQL PREPARE statements. (But 'prepare' is more -- flexible since it does not require parameter types to be -- pre-specified.) Also, although there is no libpq function for -- deleting a prepared statement, the SQL DEALLOCATE statement can be -- used for that purpose. prepare :: Connection -- ^ connection -> B.ByteString -- ^ stmtName -> B.ByteString -- ^ query -> Maybe [Oid] -- ^ paramTypes -> IO (Maybe Result) -- ^ result prepare connection stmtName query mParamTypes = resultFromConn connection $ \c -> B.useAsCString stmtName $ \s -> B.useAsCString query $ \q -> maybeWith withArray mParamTypes $ \o -> let l = maybe 0 (toEnum . length) mParamTypes in c_PQprepare c s q l o -- | Sends a request to execute a prepared statement with given -- parameters, and waits for the result. -- -- 'execPrepared' is like 'execParams', but the command to be executed -- is specified by naming a previously-prepared statement, instead of -- giving a query string. This feature allows commands that will be -- used repeatedly to be parsed and planned just once, rather than -- each time they are executed. The statement must have been prepared -- previously in the current session. 'execPrepared' is supported only -- in protocol 3.0 and later connections; it will fail when using -- protocol 2.0. -- -- The parameters are identical to 'execParams', except that the name -- of a prepared statement is given instead of a query string, and the -- paramTypes parameter is not present (it is not needed since the -- prepared statement's parameter types were determined when it was -- created). execPrepared :: Connection -- ^ connection -> B.ByteString -- ^ stmtName -> [Maybe (B.ByteString, Format)] -- ^ parameters -> Format -- ^ result format -> IO (Maybe Result) -- ^ result execPrepared connection stmtName mPairs rFmt = do let (values, lengths, formats) = foldl' accum ([],[],[]) $ reverse mPairs c_lengths = map toEnum lengths :: [CInt] n = toEnum $ length mPairs f = toEnum $ fromEnum rFmt resultFromConn connection $ \c -> B.useAsCString stmtName $ \s -> withMany (maybeWith B.useAsCString) values $ \c_values -> withArray c_values $ \vs -> withArray c_lengths $ \ls -> withArray formats $ \fs -> c_PQexecPrepared c s n vs ls fs f where accum (!a,!b,!c) Nothing = ( Nothing:a , 0:b , 0:c ) accum (!a,!b,!c) (Just (v, f)) = ( (Just v):a , (B.length v):b , (toEnum $ fromEnum f):c ) -- | Submits a request to obtain information about the specified -- prepared statement, and waits for completion. -- -- 'describePrepared' allows an application to obtain information -- about a previously prepared statement. 'describePrepared' is -- supported only in protocol 3.0 and later connections; it will fail -- when using protocol 2.0. -- -- stmtName can be empty to reference the unnamed statement, otherwise -- it must be the name of an existing prepared statement. On success, -- a 'Result' with status 'CommandOk' is returned. The functions -- 'nparams' and 'paramtype' can be applied to this 'Result' to obtain -- information about the parameters of the prepared statement, and the -- functions 'nfields', 'fname', 'ftype', etc provide information -- about the result columns (if any) of the statement. describePrepared :: Connection -> B.ByteString -- ^ stmtName -> IO (Maybe Result) describePrepared connection stmtName = resultFromConn connection $ \c -> B.useAsCString stmtName $ \s -> c_PQdescribePrepared c s -- | Submits a request to obtain information about the specified -- portal, and waits for completion. -- -- 'describePortal' allows an application to obtain information about -- a previously created portal. (libpq does not provide any direct -- access to portals, but you can use this function to inspect the -- properties of a cursor created with a DECLARE CURSOR SQL command.) -- 'describePortal' is supported only in protocol 3.0 and later -- connections; it will fail when using protocol 2.0. -- -- portalName can be empty to reference the unnamed portal, otherwise -- it must be the name of an existing portal. On success, a 'Result' -- with status 'CommandOk' is returned. The functions 'nfields', -- 'fname', 'ftype', etc can be applied to the 'Result' to obtain -- information about the result columns (if any) of the portal. describePortal :: Connection -> B.ByteString -- ^ portalName -> IO (Maybe Result) describePortal connection portalName = resultFromConn connection $ \c -> B.useAsCString portalName $ \p -> c_PQdescribePortal c p data ExecStatus = EmptyQuery -- ^ The string sent to the server was empty. | CommandOk -- ^ Successful completion of a -- command returning no data. | TuplesOk -- ^ Successful completion of a -- command returning data (such as a -- SELECT or SHOW). | CopyOut -- ^ Copy Out (from server) data -- transfer started. | CopyIn -- ^ Copy In (to server) data transfer -- started. | BadResponse -- ^ The server's response was not understood. | NonfatalError -- ^ A nonfatal error (a notice or -- warning) occurred. | FatalError -- ^ A fatal error occurred. deriving (Eq, Show) instance Enum ExecStatus where toEnum (0) = EmptyQuery {-# LINE 946 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (1) = CommandOk {-# LINE 947 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (2) = TuplesOk {-# LINE 948 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (3) = CopyOut {-# LINE 949 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (4) = CopyIn {-# LINE 950 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (5) = BadResponse {-# LINE 951 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (6) = NonfatalError {-# LINE 952 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (7) = FatalError {-# LINE 953 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum _ = error "Database.PQ.Enum.ExecStatus.toEnum: bad argument" fromEnum EmptyQuery = (0) {-# LINE 956 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum CommandOk = (1) {-# LINE 957 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum TuplesOk = (2) {-# LINE 958 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum CopyOut = (3) {-# LINE 959 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum CopyIn = (4) {-# LINE 960 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum BadResponse = (5) {-# LINE 961 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum NonfatalError = (6) {-# LINE 962 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum FatalError = (7) {-# LINE 963 "Database/PostgreSQL/LibPQ.hsc" #-} -- | Returns the result status of the command. resultStatus :: Result -> IO ExecStatus resultStatus result = enumFromResult result c_PQresultStatus -- | Converts the 'ExecStatus' returned by 'resultStatus' into a -- string describing the status code. The caller should not -- free the result. resStatus :: ExecStatus -> IO B.ByteString resStatus es = do cstr <- c_PQresStatus $ fromIntegral $ fromEnum es len <- B.c_strlen cstr fp <- newForeignPtr_ $ castPtr cstr return $ B.fromForeignPtr fp 0 $ fromIntegral len -- | Returns the error message most recently generated by an operation -- on the connection. resultErrorMessage :: Result -> IO (Maybe B.ByteString) resultErrorMessage = flip maybeBsFromResult c_PQresultErrorMessage -- | Frees the memory associated with a result. Note that using this -- function correctly is especially tricky; you need to ensure that -- no references to the result. This means no references to a value -- returned by 'getvalue', no references hiding inside an unevaluated -- thunk, etc. Improper use of this function is likely to cause a -- segfault. Also, the use of this function is not strictly necessary; -- the memory will get freed by the garbage collector when there are no -- more references to the result. unsafeFreeResult :: Result -> IO () unsafeFreeResult (Result x) = finalizeForeignPtr x data FieldCode = DiagSeverity -- ^ The severity; the field contents are ERROR, FATAL, -- or PANIC (in an error message), or WARNING, NOTICE, -- DEBUG, INFO, or LOG (in a notice message), or a -- localized translation of one of these. Always -- present. | DiagSqlstate -- ^ The SQLSTATE code for the error. The SQLSTATE code -- identifies the type of error that has occurred; it -- can be used by front-end applications to perform -- specific operations (such as error handling) in -- response to a particular database error. For a list -- of the possible SQLSTATE codes, see Appendix A. This -- field is not localizable, and is always present. | DiagMessagePrimary -- ^ The primary human-readable error message -- (typically one line). Always present. | DiagMessageDetail -- ^ Detail: an optional secondary error message -- carrying more detail about the problem. Might run to -- multiple lines. | DiagMessageHint -- ^ Hint: an optional suggestion what to do about the -- problem. This is intended to differ from detail in -- that it offers advice (potentially inappropriate) -- rather than hard facts. Might run to multiple lines. | DiagStatementPosition -- ^ A string containing a decimal integer indicating -- an error cursor position as an index into the -- original statement string. The first character has -- index 1, and positions are measured in characters -- not bytes. | DiagInternalPosition -- ^ This is defined the same as the -- 'DiagStatementPosition' field, but it is used when -- the cursor position refers to an internally -- generated command rather than the one submitted by -- the client. The 'DiagInternalQuery' field will -- always appear when this field appears. | DiagInternalQuery -- ^ The text of a failed internally-generated -- command. This could be, for example, a SQL query -- issued by a PL/pgSQL function. | DiagContext -- ^ An indication of the context in which the error -- occurred. Presently this includes a call stack -- traceback of active procedural language functions -- and internally-generated queries. The trace is one -- entry per line, most recent first. | DiagSourceFile -- ^ The file name of the source-code location where -- the error was reported. | DiagSourceLine -- ^ The line number of the source-code location where -- the error was reported. | DiagSourceFunction -- ^ The name of the source-code function reporting the -- error. deriving (Eq, Show) instance Enum FieldCode where toEnum (83) = DiagSeverity {-# LINE 1076 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (67) = DiagSqlstate {-# LINE 1077 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (77) = DiagMessagePrimary {-# LINE 1078 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (68) = DiagMessageDetail {-# LINE 1079 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (72) = DiagMessageHint {-# LINE 1080 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (80) = DiagStatementPosition {-# LINE 1081 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (112) = DiagInternalPosition {-# LINE 1082 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (113) = DiagInternalQuery {-# LINE 1083 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (87) = DiagContext {-# LINE 1084 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (70) = DiagSourceFile {-# LINE 1085 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (76) = DiagSourceLine {-# LINE 1086 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (82) = DiagSourceFunction {-# LINE 1087 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum _ = error "Database.PQ.Enum.FieldCode.toEnum: bad argument" fromEnum DiagSeverity = (83) {-# LINE 1090 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagSqlstate = (67) {-# LINE 1091 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagMessagePrimary = (77) {-# LINE 1092 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagMessageDetail = (68) {-# LINE 1093 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagMessageHint = (72) {-# LINE 1094 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagStatementPosition = (80) {-# LINE 1095 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagInternalPosition = (112) {-# LINE 1096 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagInternalQuery = (113) {-# LINE 1097 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagContext = (87) {-# LINE 1098 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagSourceFile = (70) {-# LINE 1099 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagSourceLine = (76) {-# LINE 1100 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum DiagSourceFunction = (82) {-# LINE 1101 "Database/PostgreSQL/LibPQ.hsc" #-} -- | Returns an individual field of an error report. -- -- fieldcode is an error field identifier; see the symbols listed -- below. 'Nothing' is returned if the PGresult is not an error or -- warning result, or does not include the specified field. Field -- values will normally not include a trailing newline. -- -- The client is responsible for formatting displayed information to -- meet its needs; in particular it should break long lines as -- needed. Newline characters appearing in the error message fields -- should be treated as paragraph breaks, not line breaks. -- -- Errors generated internally by libpq will have severity and primary -- message, but typically no other fields. Errors returned by a -- pre-3.0-protocol server will include severity and primary message, -- and sometimes a detail message, but no other fields. -- -- Note that error fields are only available from 'Result' objects, -- not 'Connection' objects; there is no errorField function. resultErrorField :: Result -> FieldCode -> IO (Maybe B.ByteString) resultErrorField (Result fp) fieldcode = maybeBsFromForeignPtr fp $ \res -> c_PQresultErrorField res $ fromIntegral $ fromEnum fieldcode -- $queryresultinfo -- These functions are used to extract information from a 'Result' -- that represents a successful query result (that is, one that has -- status 'TuplesOk'). They can also be used to extract information -- from a successful Describe operation: a Describe's result has all -- the same column information that actual execution of the query -- would provide, but it has zero rows. For objects with other status -- values, these functions will act as though the result has zero rows -- and zero columns. -- | Returns the number of rows (tuples) in the query result. Because -- it returns an integer result, large result sets might overflow the -- return value on 32-bit operating systems. ntuples :: Result -> IO Row ntuples (Result res) = withForeignPtr res (return . toRow . c_PQntuples) -- | Returns the number of columns (fields) in each row of the query -- result. nfields :: Result -> IO Column nfields (Result res) = withForeignPtr res (return . toColumn . c_PQnfields) newtype Column = Col CInt deriving (Eq, Ord, Show, Enum, Num) newtype Row = Row CInt deriving (Eq, Ord, Show, Enum, Num) toColumn :: (Integral a) => a -> Column toColumn = Col . fromIntegral toRow :: (Integral a) => a -> Row toRow = Row . fromIntegral -- | Returns the column name associated with the given 'Column' -- number. Column numbers start at 0. fname :: Result -> Column -> IO (Maybe B.ByteString) fname result (Col colNum) = maybeBsFromResult result $ \fp -> c_PQfname fp colNum -- | Returns the column number associated with the given column name. fnumber :: Result -> B.ByteString -> IO (Maybe Column) fnumber (Result res) columnName = do num <- withForeignPtr res $ \resPtr -> B.useAsCString columnName $ \columnNamePtr -> c_PQfnumber resPtr columnNamePtr return $ if num == -1 then Nothing else Just $ toColumn num -- | Returns the OID of the table from which the given column was -- fetched. Column numbers start at 0. ftable :: Result -> Column -> IO Oid ftable result (Col colNum) = withResult result $ \ptr -> c_PQftable ptr colNum -- | Returns the column number (within its table) of the column making -- up the specified query result column. Query-result column numbers -- start at 0, but table columns have nonzero numbers. ftablecol :: Result -> Column -> IO Column ftablecol result (Col colNum) = fmap Col $ withResult result $ \p -> c_PQftablecol p colNum -- | Returns the 'Format' of the given column. Column numbers start at -- 0. fformat :: Result -> Column -> IO Format fformat result (Col colNum) = enumFromResult result $ \ptr -> c_PQfformat ptr colNum -- | Returns the data type associated with the given column -- number. The 'Oid' returned is the internal OID number of the -- type. Column numbers start at 0. -- -- You can query the system table pg_type to obtain the names and -- properties of the various data types. The OIDs of the built-in data -- types are defined in the file src/include/catalog/pg_type.h in the -- source tree. ftype :: Result -> Column -> IO Oid ftype result (Col colNum) = withResult result $ \ptr -> c_PQftype ptr colNum -- | Returns the type modifier of the column associated with the given -- column number. Column numbers start at 0. -- -- The interpretation of modifier values is type-specific; they -- typically indicate precision or size limits. The value -1 is used -- to indicate "no information available". Most data types do not use -- modifiers, in which case the value is always -1. fmod :: Result -> Column -> IO Int fmod result (Col colNum) = numFromResult result $ \ptr -> c_PQfmod ptr colNum -- | Returns the size in bytes of the column associated with the given -- column number. Column numbers start at 0. -- -- 'fsize' returns the space allocated for this column in a database -- row, in other words the size of the server's internal -- representation of the data type. (Accordingly, it is not really -- very useful to clients.) A negative value indicates the data type -- is variable-length. fsize :: Result -> Column -> IO Int fsize result (Col colNum) = numFromResult result $ \ptr -> c_PQfsize ptr colNum -- | Returns a single field value of one row of a PGresult. Row and -- column numbers start at 0. -- -- For convenience, this binding uses 'getisnull' and 'getlength' to -- help construct the result. -- -- Note: The 'ByteString' returned holds a reference to the Result. As -- long as ByteString is live, the Result will not be garbage -- collected. 'getvalue'' returns a copy of the data. getvalue :: Result -> Row -> Column -> IO (Maybe B.ByteString) getvalue (Result fp) (Row rowNum) (Col colNum) = withForeignPtr fp $ \ptr -> do isnull <- c_PQgetisnull ptr rowNum colNum if toEnum $ fromIntegral isnull then return $ Nothing else do cstr <- c_PQgetvalue ptr rowNum colNum l <- c_PQgetlength ptr rowNum colNum fp' <- FC.newForeignPtr (castPtr cstr) finalizer return $ Just $ B.fromForeignPtr fp' 0 $ fromIntegral l where finalizer = touchForeignPtr fp -- | Returns a copy of a single field value of one row of a -- PGresult. Row and column numbers start at 0. -- -- For convenience, this binding uses 'getisnull' and 'getlength' to -- help construct the result. getvalue' :: Result -> Row -> Column -> IO (Maybe B.ByteString) getvalue' (Result fp) (Row rowNum) (Col colNum) = withForeignPtr fp $ \ptr -> do isnull <- c_PQgetisnull ptr rowNum colNum if toEnum $ fromIntegral isnull then return $ Nothing else do cstr <- c_PQgetvalue ptr rowNum colNum l <- fromIntegral `fmap` c_PQgetlength ptr rowNum colNum Just `fmap` B.packCStringLen (cstr, l) -- | Tests a field for a null value. Row and column numbers start at -- 0. getisnull :: Result -> Row -> Column -> IO Bool getisnull result (Row rowNum) (Col colNum) = enumFromResult result $ \ptr -> c_PQgetisnull ptr rowNum colNum -- | Returns the actual length of a field value in bytes. Row and -- column numbers start at 0. -- -- This is the actual data length for the particular data value, that -- is, the size of the object pointed to by 'getvalue'. For text data -- format this is the same as strlen(). For binary format this is -- essential information. Note that one should not rely on 'fsize' to -- obtain the actual data length. getlength :: Result -> Row -> Column -> IO Int getlength result (Row rowNum) (Col colNum) = numFromResult result $ \ptr -> c_PQgetlength ptr rowNum colNum -- | Returns the number of parameters of a prepared statement. -- -- This function is only useful when inspecting the result of -- PQdescribePrepared. For other types of queries it will return zero. nparams :: Result -> IO Int nparams result = numFromResult result c_PQnparams -- | Returns the data type of the indicated statement -- parameter. Parameter numbers start at 0. -- -- This function is only useful when inspecting the result of -- 'describePrepared'. For other types of queries it will return zero. paramtype :: Result -> Int -- ^ param_number -> IO Oid paramtype result param_number = withResult result $ \p -> c_PQparamtype p $ fromIntegral param_number -- $othercommands -- These functions are used to extract other information from PGresult -- objects. -- | Returns the command status tag from the SQL command that -- generated the PGresult. -- -- Commonly this is just the name of the command, but it might include -- additional data such as the number of rows processed. cmdStatus :: Result -> IO (Maybe B.ByteString) cmdStatus = flip maybeBsFromResult c_PQcmdStatus -- | Returns the number of rows affected by the SQL command. -- -- This function returns a string containing the number of rows -- affected by the SQL statement that generated the 'Result'. This -- function can only be used following the execution of a SELECT, -- CREATE TABLE AS, INSERT, UPDATE, DELETE, MOVE, FETCH, or COPY -- statement, or an EXECUTE of a prepared query that contains an -- INSERT, UPDATE, or DELETE statement. If the command that generated -- the 'Result' was anything else, 'cmdTuples' returns an empty -- string. cmdTuples :: Result -> IO (Maybe B.ByteString) cmdTuples = flip maybeBsFromResult c_PQcmdTuples -- | Returns the 'Oid' of the inserted row, if the SQL command was an -- INSERT that inserted exactly one row into a table that has OIDs, or -- a EXECUTE of a prepared query containing a suitable INSERT -- statement. Otherwise, this function returns 'Nothing'. This -- function will also return 'Nothing' if the table affected by the -- INSERT statement does not contain OIDs. oidValue :: Result -> IO (Maybe Oid) oidValue result = withResult result $ \ptr -> do oid <- c_PQoidValue ptr return $ toMaybeOid oid -- | Escapes a string for use within an SQL command. This is useful -- when inserting data values as literal constants in SQL -- commands. Certain characters (such as quotes and backslashes) must -- be escaped to prevent them from being interpreted specially by the -- SQL parser. escapeStringConn :: Connection -> B.ByteString -> IO (Maybe B.ByteString) escapeStringConn connection bs = withConn connection $ \conn -> B.unsafeUseAsCStringLen bs $ \(from, bslen) -> alloca $ \err -> do to <- mallocBytes (bslen*2+1) num <- c_PQescapeStringConn conn to from (fromIntegral bslen) err stat <- peek err case stat of 0 -> do let i = fromIntegral num tore <- reallocBytes to i tofp <- newForeignPtr finalizerFree tore return $ Just $ B.fromForeignPtr tofp 0 i _ -> do free to return Nothing -- | Escapes binary data for use within an SQL command with the type -- bytea. As with 'escapeStringConn', this is only used when inserting -- data directly into an SQL command string. escapeByteaConn :: Connection -> B.ByteString -> IO (Maybe B.ByteString) escapeByteaConn connection bs = withConn connection $ \conn -> B.unsafeUseAsCStringLen bs $ \(from, bslen) -> alloca $ \to_length -> do to <- c_PQescapeByteaConn conn from (fromIntegral bslen) to_length if to == nullPtr then return Nothing else do tofp <- newForeignPtr p_PQfreemem to l <- peek to_length return $ Just $ B.fromForeignPtr tofp 0 ((fromIntegral l) - 1) -- | Converts a 'ByteString' representation of binary data into binary -- data - the reverse of 'PQescapeByteaConn'. This is needed when -- retrieving bytea data in text format, but not when retrieving it in -- binary format. -- -- The parameter points to a string such as might be returned by -- 'getvalue' when applied to a bytea column. 'unescapeBytea' converts -- this string representation into its binary representation. It -- returns a 'ByteString', or 'Nothing' on error. -- -- This conversion is not exactly the inverse of 'escapeByteaConn', -- because the string is not expected to be "escaped" when received -- from 'getvalue'. In particular this means there is no need for -- string quoting considerations, and so no need for a 'Connection' -- parameter. unescapeBytea :: B.ByteString -> IO (Maybe B.ByteString) unescapeBytea bs = B.useAsCString bs $ \from -> alloca $ \to_length -> do to <- c_PQunescapeBytea from to_length if to == nullPtr then return Nothing else do tofp <- newForeignPtr p_PQfreemem to l <- peek to_length return $ Just $ B.fromForeignPtr tofp 0 $ fromIntegral l -- $copy -- -- This provides support for PostgreSQL's @COPY FROM@ facility. -- -- For more information, see: -- -- * <http://www.postgresql.org/docs/current/static/sql-copy.html> -- -- * <http://www.postgresql.org/docs/current/static/libpq-copy.html> -- data CopyInResult = CopyInOk -- ^ The data was sent. | CopyInError -- ^ An error occurred (use 'errorMessage' -- to retrieve details). | CopyInWouldBlock -- ^ The data was not sent because the -- attempt would block (this case is only -- possible if the connection is in -- nonblocking mode) Wait for -- write-ready (e.g. by using -- 'Control.Concurrent.threadWaitWrite' -- on the 'socket') and try again. deriving (Eq, Show) toCopyInResult :: CInt -> CopyInResult toCopyInResult n | n < 0 = CopyInError | n == 0 = CopyInWouldBlock | otherwise = CopyInOk -- | Send raw @COPY@ data to the server during the 'CopyIn' state. putCopyData :: Connection -> B.ByteString -> IO CopyInResult putCopyData conn bs = B.unsafeUseAsCStringLen bs $ putCopyCString conn putCopyCString :: Connection -> CStringLen -> IO CopyInResult putCopyCString conn (str, len) = fmap toCopyInResult $ withConn conn $ \ptr -> c_PQputCopyData ptr str (fromIntegral len) -- | Send end-of-data indication to the server during the 'CopyIn' state. -- -- * @putCopyEnd conn Nothing@ ends the 'CopyIn' operation successfully. -- -- * @putCopyEnd conn (Just errormsg)@ forces the @COPY@ to fail, with -- @errormsg@ used as the error message. -- -- After 'putCopyEnd' returns 'CopyOk', call 'getResult' to obtain the final -- result status of the @COPY@ command. Then return to normal operation. putCopyEnd :: Connection -> Maybe B.ByteString -> IO CopyInResult putCopyEnd conn Nothing = fmap toCopyInResult $ withConn conn $ \ptr -> c_PQputCopyEnd ptr nullPtr putCopyEnd conn (Just errormsg) = fmap toCopyInResult $ B.useAsCString errormsg $ \errormsg_cstr -> withConn conn $ \ptr -> c_PQputCopyEnd ptr errormsg_cstr data CopyOutResult = CopyOutRow !B.ByteString -- ^ Data representing a single row of the result | CopyOutWouldBlock -- ^ A complete row is not yet available. This -- case is only possible when 'getCopyData' is -- has the async parameter set to 'True'. | CopyOutDone -- ^ No more rows are available | CopyOutError -- ^ An error occurred (e.g. the connection is -- not in the 'CopyOut' state). Call -- 'errorMessage' for more information. deriving Show -- | Receive raw @COPY@ data from the server during the 'CopyOut' state. -- The boolean parameter determines whether or not the call will block -- while waiting for data. getCopyData :: Connection -> Bool -> IO CopyOutResult getCopyData conn async = alloca $ \strp -> withConn conn $ \c -> do len <- c_PQgetCopyData c strp (if async then 1 else 0) if len <= 0 then return $ case compare len (-1) of LT -> CopyOutError EQ -> CopyOutDone GT -> CopyOutWouldBlock else do fp <- newForeignPtr p_PQfreemem =<< peek strp return (CopyOutRow (B.fromForeignPtr fp 0 (fromIntegral len))) -- $asynccommand -- The 'exec' function is adequate for submitting commands in normal, -- synchronous applications. It has a couple of deficiencies, however, -- that can be of importance to some users: -- -- * 'exec' waits for the command to be completed. The application -- might have other work to do (such as maintaining a user -- interface), in which case it won't want to block waiting for the -- response. -- -- * Since the execution of the client application is suspended -- while it waits for the result, it is hard for the application to -- decide that it would like to try to cancel the ongoing -- command. (It can be done from a signal handler, but not -- otherwise.) -- -- * 'exec' can return only one 'Result'. If the submitted command -- string contains multiple SQL commands, all but the last 'Result' -- are discarded by 'exec'. -- -- Applications that do not like these limitations can instead use the -- underlying functions that 'exec' is built from: 'sendQuery' and -- 'getResult'. There are also 'sendQueryParams', 'sendPrepare', -- 'sendQueryPrepared', 'sendDescribePrepared', and -- 'sendDescribePortal', which can be used with 'getResult' to -- duplicate the functionality of 'execParams', 'prepare', -- 'execPrepared', 'describePrepared', and 'describePortal' -- respectively. -- | Submits a command to the server without waiting for the -- result(s). 'True' is returned if the command was successfully -- dispatched and 'False' if not (in which case, use 'errorMessage' to -- get more information about the failure). sendQuery :: Connection -> B.ByteString -> IO Bool sendQuery connection query = enumFromConn connection $ \p -> B.useAsCString query $ c_PQsendQuery p -- | Submits a command and separate parameters to the server without -- waiting for the result(s). sendQueryParams :: Connection -> B.ByteString -> [Maybe (Oid, B.ByteString, Format)] -> Format -> IO Bool sendQueryParams connection statement params rFmt = do let (oids, values, lengths, formats) = foldl' accum ([],[],[],[]) $ reverse params c_lengths = map toEnum lengths :: [CInt] n = toEnum $ length params f = toEnum $ fromEnum rFmt enumFromConn connection $ \c -> B.useAsCString statement $ \s -> withArray oids $ \ts -> withMany (maybeWith B.useAsCString) values $ \c_values -> withArray c_values $ \vs -> withArray c_lengths $ \ls -> withArray formats $ \fs -> c_PQsendQueryParams c s n ts vs ls fs f where accum (!a,!b,!c,!d) Nothing = ( invalidOid:a , Nothing:b , 0:c , 0:d ) accum (!a,!b,!c,!d) (Just (t,v,f)) = ( t:a , (Just v):b , (B.length v):c , (toEnum $ fromEnum f):d ) -- | Sends a request to create a prepared statement with the given -- parameters, without waiting for completion. sendPrepare :: Connection -> B.ByteString -> B.ByteString -> Maybe [Oid] -> IO Bool sendPrepare connection stmtName query mParamTypes = enumFromConn connection $ \c -> B.useAsCString stmtName $ \s -> B.useAsCString query $ \q -> maybeWith withArray mParamTypes $ \o -> let l = maybe 0 (toEnum . length) mParamTypes in c_PQsendPrepare c s q l o -- | Sends a request to execute a prepared statement with given -- parameters, without waiting for the result(s). sendQueryPrepared :: Connection -> B.ByteString -> [Maybe (B.ByteString, Format)] -> Format -> IO Bool sendQueryPrepared connection stmtName mPairs rFmt = do let (values, lengths, formats) = foldl' accum ([],[],[]) $ reverse mPairs c_lengths = map toEnum lengths :: [CInt] n = toEnum $ length mPairs f = toEnum $ fromEnum rFmt enumFromConn connection $ \c -> B.useAsCString stmtName $ \s -> withMany (maybeWith B.useAsCString) values $ \c_values -> withArray c_values $ \vs -> withArray c_lengths $ \ls -> withArray formats $ \fs -> c_PQsendQueryPrepared c s n vs ls fs f where accum (!a,!b,!c) Nothing = ( Nothing:a , 0:b , 0:c ) accum (!a,!b,!c) (Just (v, f)) = ( (Just v):a , (B.length v):b , (toEnum $ fromEnum f):c ) -- | Submits a request to obtain information about the specified -- prepared statement, without waiting for completion. -- -- This is an asynchronous version of 'describePrepared': it returns -- 'True' if it was able to dispatch the request, and 'False' if -- not. After a successful call, call 'getResult' to obtain the -- results. The function's parameters are handled identically to -- 'describePrepared'. Like 'describePrepared', it will not work on -- 2.0-protocol connections. sendDescribePrepared :: Connection -> B.ByteString -- ^ stmtName -> IO Bool sendDescribePrepared connection stmtName = enumFromConn connection $ \c -> B.useAsCString stmtName $ \s -> c_PQsendDescribePrepared c s -- | Submits a request to obtain information about the specified -- portal, without waiting for completion. -- -- This is an asynchronous version of 'describePortal': it returns -- 'True' if it was able to dispatch the request, and 'False' if -- not. After a successful call, call 'getResult' to obtain the -- results. The function's parameters are handled identically to -- 'describePortal'. Like 'describePortal', it will not work on -- 2.0-protocol connections. sendDescribePortal :: Connection -> B.ByteString -- ^ portalName -> IO Bool sendDescribePortal connection portalName = enumFromConn connection $ \c -> B.useAsCString portalName $ \p -> c_PQsendDescribePortal c p -- | Waits for the next result from a prior 'sendQuery', -- 'sendQueryParams', 'sendPrepare', or 'sendQueryPrepared' call, and -- returns it. A null pointer is returned when the command is complete -- and there will be no more results. getResult :: Connection -> IO (Maybe Result) getResult connection = do resPtr <- withConn connection c_PQgetResult if resPtr == nullPtr then return Nothing else (Just . Result) `fmap` newForeignPtr p_PQclear resPtr -- | If input is available from the server, consume it. -- -- 'consumeInput' normally returns 'True' indicating "no error", but -- returns 'False' if there was some kind of trouble (in which case -- 'errorMessage' can be consulted). Note that the result does not say -- whether any input data was actually collected. After calling -- 'consumeInput', the application can check 'isBusy' and/or -- 'notifies' to see if their state has changed. consumeInput :: Connection -> IO Bool consumeInput connection = enumFromConn connection c_PQconsumeInput -- | Returns True if a command is busy, that is, getResult would block -- waiting for input. A False return indicates that getResult can be -- called with assurance of not blocking. -- -- 'isBusy' will not itself attempt to read data from the server; -- therefore 'consumeInput' must be invoked first, or the busy state -- will never end. isBusy :: Connection -> IO Bool isBusy connection = enumFromConn connection c_PQisBusy -- | Sets the nonblocking status of the connection. setnonblocking :: Connection -> Bool -> IO Bool setnonblocking connection blocking = do let arg = fromIntegral $ fromEnum blocking stat <- withConn connection $ \ptr -> c_PQsetnonblocking ptr arg return $ stat == 0 -- | Returns the blocking status of the database connection. isnonblocking :: Connection -> IO Bool isnonblocking connection = enumFromConn connection c_PQisnonblocking data FlushStatus = FlushOk | FlushFailed | FlushWriting deriving (Eq, Show) -- | Attempts to flush any queued output data to the server. Returns -- 'FlushOk' if successful (or if the send queue is empty), -- 'FlushFailed' if it failed for some reason, or 'FlushWriting' if it -- was unable to send all the data in the send queue yet (this case -- can only occur if the connection is nonblocking). flush :: Connection -> IO FlushStatus flush connection = do stat <- withConn connection c_PQflush return $ case stat of 0 -> FlushOk 1 -> FlushWriting _ -> FlushFailed -- $cancel -- A client application can request cancellation of a command that is -- still being processed by the server, using the functions described -- in this section. -- | Contains the information needed to cancel a command issued -- through a particular database connection. newtype Cancel = Cancel (ForeignPtr PGcancel) deriving (Eq, Show) data PGcancel -- | Creates a data structure containing the information needed to -- cancel a command issued through a particular database connection. -- -- 'getCancel' creates a 'Cancel' object given a 'Connection'. It will -- return 'Nothing' if the given conn is an invalid connection. getCancel :: Connection -> IO (Maybe Cancel) getCancel connection = withConn connection $ \conn -> do ptr <- c_PQgetCancel conn if ptr == nullPtr then return Nothing else do fp <- newForeignPtr p_PQfreeCancel ptr return $ Just $ Cancel fp -- | Requests that the server abandon processing of the current -- command. -- -- The return value is 'Right ()' if the cancel request was -- successfully dispatched and if not, 'Left B.ByteString' containing -- an error message explaining why not. -- -- Successful dispatch is no guarantee that the request will have any -- effect, however. If the cancellation is effective, the current -- command will terminate early and return an error result. If the -- cancellation fails (say, because the server was already done -- processing the command), then there will be no visible result at -- all. cancel :: Cancel -> IO (Either B.ByteString ()) cancel (Cancel fp) = withForeignPtr fp $ \ptr -> do errbuf <- mallocBytes errbufsize res <- c_PQcancel ptr errbuf $ fromIntegral errbufsize case res of 1 -> do free errbuf return $ Right () _ -> do l <- fromIntegral `fmap` B.c_strlen errbuf fp' <- newForeignPtr finalizerFree $ castPtr errbuf return $ Left $ B.fromForeignPtr fp' 0 l where errbufsize = 256 -- $asyncnotification -- PostgreSQL offers asynchronous notification via the LISTEN and -- NOTIFY commands. A client session registers its interest in a -- particular notification channel with the LISTEN command (and can -- stop listening with the UNLISTEN command). All sessions listening -- on a particular channel will be notified asynchronously when a -- NOTIFY command with that channel name is executed by any session. A -- \"payload\" string can be passed to communicate additional data to -- the listeners. -- -- libpq applications submit LISTEN, UNLISTEN, and NOTIFY commands as -- ordinary SQL commands. The arrival of NOTIFY messages can -- subsequently be detected by calling 'notifies'. data Notify = Notify { notifyRelname :: B.ByteString -- ^ notification channel name , notifyBePid :: CPid -- ^ process ID of notifying server process , notifyExtra :: B.ByteString -- ^ notification payload string } deriving Show {-# LINE 1868 "Database/PostgreSQL/LibPQ.hsc" #-} instance Storable Notify where sizeOf _ = (16) {-# LINE 1870 "Database/PostgreSQL/LibPQ.hsc" #-} alignment _ = 4 {-# LINE 1872 "Database/PostgreSQL/LibPQ.hsc" #-} peek ptr = do relname <- B.packCString =<< (\hsc_ptr -> peekByteOff hsc_ptr 0) ptr {-# LINE 1875 "Database/PostgreSQL/LibPQ.hsc" #-} extra <- B.packCString =<< (\hsc_ptr -> peekByteOff hsc_ptr 8) ptr {-# LINE 1876 "Database/PostgreSQL/LibPQ.hsc" #-} be_pid <- fmap f $ (\hsc_ptr -> peekByteOff hsc_ptr 4) ptr {-# LINE 1877 "Database/PostgreSQL/LibPQ.hsc" #-} return $ Notify relname be_pid extra where f :: CInt -> CPid f = fromIntegral poke ptr (Notify a b c) = B.useAsCString a $ \a' -> B.useAsCString c $ \c' -> do (\hsc_ptr -> pokeByteOff hsc_ptr 0) ptr a' {-# LINE 1886 "Database/PostgreSQL/LibPQ.hsc" #-} (\hsc_ptr -> pokeByteOff hsc_ptr 4) ptr (fromIntegral b :: CInt) {-# LINE 1887 "Database/PostgreSQL/LibPQ.hsc" #-} (\hsc_ptr -> pokeByteOff hsc_ptr 8) ptr c' {-# LINE 1888 "Database/PostgreSQL/LibPQ.hsc" #-} -- | Returns the next notification from a list of unhandled -- notification messages received from the server. It returns a -- 'Nothing' if there are no pending notifications. Once a -- notification is returned from notifies, it is considered handled -- and will be removed from the list of notifications. notifies :: Connection -> IO (Maybe Notify) notifies connection = withConn connection $ \ptr -> do mn <- c_PQnotifies ptr if mn == nullPtr then return Nothing else do result <- Just `fmap` peek mn c_PQfreemem mn return result -- $control -- These functions control miscellaneous details of libpq's behavior. -- | Returns the client encoding. clientEncoding :: Connection -> IO B.ByteString clientEncoding connection = withConn connection $ \ptr -> do i <- c_PQclientEncoding ptr cstr <- c_pg_encoding_to_char i len <- B.c_strlen cstr fp <- newForeignPtr_ $ castPtr cstr return $ B.fromForeignPtr fp 0 $ fromIntegral len -- | Sets the client encoding. setClientEncoding :: Connection -> B.ByteString -> IO Bool setClientEncoding connection enc = do stat <- withConn connection $ \c -> B.useAsCString enc $ \s -> c_PQsetClientEncoding c s return $ stat == 0 data Verbosity = ErrorsTerse | ErrorsDefault | ErrorsVerbose deriving (Eq, Show) instance Enum Verbosity where toEnum (0) = ErrorsTerse {-# LINE 1939 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (1) = ErrorsDefault {-# LINE 1940 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum (2) = ErrorsVerbose {-# LINE 1941 "Database/PostgreSQL/LibPQ.hsc" #-} toEnum _ = error "Database.PQ.Enum.Verbosity.toEnum: bad argument" fromEnum ErrorsTerse = (0) {-# LINE 1944 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum ErrorsDefault = (1) {-# LINE 1945 "Database/PostgreSQL/LibPQ.hsc" #-} fromEnum ErrorsVerbose = (2) {-# LINE 1946 "Database/PostgreSQL/LibPQ.hsc" #-} -- | Determines the verbosity of messages returned by 'errorMessage' -- and 'resultErrorMessage'. -- -- 'setErrorVerbosity' sets the verbosity mode, returning the -- connection's previous setting. In 'ErrorsTerse' mode, returned -- messages include severity, primary text, and position only; this -- will normally fit on a single line. The default mode produces -- messages that include the above plus any detail, hint, or context -- fields (these might span multiple lines). The 'ErrorsVerbose' mode -- includes all available fields. Changing the verbosity does not -- affect the messages available from already-existing 'Result' -- objects, only subsequently-created ones. setErrorVerbosity :: Connection -> Verbosity -> IO Verbosity setErrorVerbosity connection verbosity = enumFromConn connection $ \p -> c_PQsetErrorVerbosity p $ fromIntegral $ fromEnum verbosity withConn :: Connection -> (Ptr PGconn -> IO b) -> IO b withConn connection f = withConn' connection $ flip withForeignPtr f withConn' :: Connection -> (ForeignPtr PGconn -> IO b) -> IO b withConn' (Conn fp) f = f fp enumFromConn :: (Integral a, Enum b) => Connection -> (Ptr PGconn -> IO a) -> IO b enumFromConn connection f = fmap (toEnum . fromIntegral) $ withConn connection f resultFromConn :: Connection -> (Ptr PGconn -> IO (Ptr PGresult)) -> IO (Maybe Result) resultFromConn connection f = do resPtr <- withConn connection f if resPtr == nullPtr then return Nothing else (Just . Result) `fmap` newForeignPtr p_PQclear resPtr withResult :: Result -> (Ptr PGresult -> IO b) -> IO b withResult (Result fp) f = withForeignPtr fp f numFromResult :: (Integral a, Num b) => Result -> (Ptr PGresult -> IO a) -> IO b numFromResult result f = fmap fromIntegral $ withResult result f enumFromResult :: (Integral a, Enum b) => Result -> (Ptr PGresult -> IO a) -> IO b enumFromResult result f = fmap (toEnum . fromIntegral) $ withResult result f -- | Returns a ByteString with a finalizer that touches the ForeignPtr -- PGresult that \"owns\" the CString to keep it alive. -- -- The CString must be a null terminated c string. nullPtrs are -- treated as 'Nothing'. maybeBsFromResult :: Result -> (Ptr PGresult -> IO CString) -> IO (Maybe B.ByteString) maybeBsFromResult (Result res) f = maybeBsFromForeignPtr res f -- | Returns a ByteString with a finalizer that touches the ForeignPtr -- that \"owns\" the CString to keep it alive. -- -- The CString must be a null terminated c string. nullPtrs are -- treated as 'Nothing'. maybeBsFromForeignPtr :: ForeignPtr a -> (Ptr a -> IO CString) -> IO (Maybe B.ByteString) maybeBsFromForeignPtr fp f = withForeignPtr fp $ \p -> do cstr <- f p if cstr == nullPtr then return Nothing else do l <- fromIntegral `fmap` B.c_strlen cstr fp' <- FC.newForeignPtr (castPtr cstr) finalizer return $ Just $ B.fromForeignPtr fp' 0 l where finalizer = touchForeignPtr fp -- -- | Returns a ByteString with a finalizer that touches the ForeignPtr -- -- that \"owns\" the CStringLen to keep it alive. -- bsFromForeignPtrLen :: ForeignPtr a -- -> (Ptr a -> IO CStringLen) -- -> IO B.ByteString -- bsFromForeignPtrLen fp f = -- withForeignPtr fp $ \p -> -- do (cstr, l) <- f p -- if cstr == nullPtr -- then return "" -- else do fp' <- FC.newForeignPtr (castPtr cstr) finalizer -- return $ B.fromForeignPtr fp' 0 l -- where -- finalizer = touchForeignPtr fp -- $largeobjects -- | LoFd is a Large Object (pseudo) File Descriptor. It is understood by -- libpq but not by operating system calls. newtype LoFd = LoFd CInt deriving (Eq, Ord, Show) loMode :: IOMode -> CInt loMode mode = case mode of ReadMode -> (262144) {-# LINE 2068 "Database/PostgreSQL/LibPQ.hsc" #-} WriteMode -> (131072) {-# LINE 2069 "Database/PostgreSQL/LibPQ.hsc" #-} ReadWriteMode -> (262144) .|. (131072) {-# LINE 2070 "Database/PostgreSQL/LibPQ.hsc" #-} AppendMode -> (131072) {-# LINE 2071 "Database/PostgreSQL/LibPQ.hsc" #-} toMaybeOid :: Oid -> Maybe Oid toMaybeOid oid | oid == invalidOid = Nothing | otherwise = Just oid {-# INLINE toMaybeOid #-} nonnegInt :: CInt -> Maybe Int nonnegInt x = if x < 0 then Nothing else Just (fromIntegral x) {-# INLINE nonnegInt #-} negError :: CInt -> Maybe () negError x = if x < 0 then Nothing else Just () {-# INLINE negError #-} -- | Creates a new large object, returns the Object ID of the newly created -- object. loCreat :: Connection -> IO (Maybe Oid) loCreat connection = withConn connection $ \c -> do toMaybeOid `fmap` c_lo_creat c (loMode ReadMode) -- | Creates a new large object with a particular Object ID. Returns -- 'Nothing' if the requested Object ID is already in use by some other -- large object or other failure. If 'invalidOid' is used as a parameter, -- then 'loCreate' will assign an unused 'Oid'. loCreate :: Connection -> Oid -> IO (Maybe Oid) loCreate connection oid = withConn connection $ \c -> do toMaybeOid `fmap` c_lo_create c oid -- | Imports an operating system file as a large object. Note that the -- file is read by the client interface library, not by the server; so it -- must exist in the client file system and be readable by the client -- application. loImport :: Connection -> FilePath -> IO (Maybe Oid) loImport connection filepath = withConn connection $ \c -> do withCString filepath $ \f -> do toMaybeOid `fmap` c_lo_import c f -- | Imports an operating system file as a large object with the given -- Object ID. Combines the behavior of 'loImport' and 'loCreate' loImportWithOid :: Connection -> FilePath -> Oid -> IO (Maybe Oid) loImportWithOid connection filepath oid = withConn connection $ \c -> do withCString filepath $ \f -> do toMaybeOid `fmap` c_lo_import_with_oid c f oid -- | Exports a large object into a operating system file. Note that -- the file is written by the client interface library, not the server. -- Returns 'Just ()' on success, 'Nothing' on failure. loExport :: Connection -> Oid -> FilePath -> IO (Maybe ()) loExport connection oid filepath = withConn connection $ \c -> do withCString filepath $ \f -> do negError `fmap` c_lo_export c oid f -- | Opens an existing large object for reading or writing. The Oid specifies -- the large object to open. A large object cannot be opened before it is -- created. A large object descriptor is returned for later use in 'loRead', -- 'loWrite', 'loSeek', 'loTell', and 'loClose'. The descriptor is only valid -- for the duration of the current transation. On failure, 'Nothing' is -- returned. -- -- The server currently does not distinguish between 'WriteMode' and -- 'ReadWriteMode'; write-only modes are not enforced. However there -- is a significant difference between 'ReadMode' and the other modes: -- with 'ReadMode' you cannot write on the descriptor, and the data read -- from it will reflect the contents of the large object at the time of -- the transaction snapshot that was active when 'loOpen' was executed, -- regardless of later writes by this or other transactions. Reading from -- a descriptor opened in 'WriteMode', 'ReadWriteMode', or 'AppendMode' -- returns data that reflects all writes of other committed transactions -- as well as the writes of the current transaction. This is similar to -- the behavior of @REPEATABLE READ@ versus @READ COMMITTED@ transaction -- modes for ordinary SQL @SELECT@ commands. loOpen :: Connection -> Oid -> IOMode -> IO (Maybe LoFd) loOpen connection oid mode = withConn connection $ \c -> do fd <- c_lo_open c oid (loMode mode) case fd of -1 -> return Nothing _ | mode /= AppendMode -> return (Just (LoFd fd)) | otherwise -> do -- The Large Object API does not directly support AppendMode, -- so we emulate it. -- FIXME: review this emulation as it and/or the error -- handling is likely to be slightly wrong. Start by -- reading the source of lo_open, lo_lseek, and -- lo_close. err <- c_lo_lseek c fd 0 (2) {-# LINE 2169 "Database/PostgreSQL/LibPQ.hsc" #-} case err of -1 -> do -- the lo_lseek failed, so we try to close the fd -- I'm not sure what to do if lo_close fails so I am -- ignoring it. This might obscure the error message -- available from PQerrorMessage _ <- c_lo_close c fd return Nothing _ -> return (Just (LoFd fd)) -- | @loWrite conn fd buf@ writes the bytestring @buf@ to the large object -- descriptor @fd@. The number of bytes actually written is returned. -- In the event of an error, 'Nothing' is returned. loWrite :: Connection -> LoFd -> B.ByteString -> IO (Maybe Int) loWrite connection (LoFd fd) bytes = withConn connection $ \c -> do B.unsafeUseAsCStringLen bytes $ \(byteptr,len) -> do nonnegInt `fmap` c_lo_write c fd byteptr (fromIntegral len) -- | @loRead conn fd len@ reads up to @len@ bytes from the large object -- descriptor @fd@. In the event of an error, 'Nothing' is returned. loRead :: Connection -> LoFd -> Int -> IO (Maybe B.ByteString) loRead connection (LoFd !fd) !maxlen = withConn connection $ \c -> do buf <- mallocBytes maxlen len_ <- c_lo_read c fd buf (fromIntegral maxlen) let len = fromIntegral len_ if len < 0 then do free buf return Nothing else do bufre <- reallocBytes buf len buffp <- newForeignPtr finalizerFree bufre return (Just (B.fromForeignPtr buffp 0 len)) -- | Changes the current read or write location associated with -- a large object descriptor. The return value is the new location -- pointer, or 'Nothing' on error. loSeek :: Connection -> LoFd -> SeekMode -> Int -> IO (Maybe Int) loSeek connection (LoFd fd) seekmode delta = withConn connection $ \c -> do let d = fromIntegral delta pos <- c_lo_lseek c fd d $ case seekmode of AbsoluteSeek -> 0 {-# LINE 2218 "Database/PostgreSQL/LibPQ.hsc" #-} RelativeSeek -> 1 {-# LINE 2219 "Database/PostgreSQL/LibPQ.hsc" #-} SeekFromEnd -> 2 {-# LINE 2220 "Database/PostgreSQL/LibPQ.hsc" #-} return (nonnegInt pos) -- | Obtains the current read or write location of a large object descriptor. loTell :: Connection -> LoFd -> IO (Maybe Int) loTell connection (LoFd fd) = withConn connection $ \c -> do nonnegInt `fmap` c_lo_tell c fd -- | Truncates a large object to a given length. If the length is greater -- than the current large object, then the large object is extended with -- null bytes. ('\x00') -- -- The file offest is not changed. -- -- 'loTruncate' is new as of PostgreSQL 8.3; if this function is run against -- an older server version, it will fail and return 'Nothing' loTruncate :: Connection -> LoFd -> Int -> IO (Maybe ()) loTruncate connection (LoFd fd) size = withConn connection $ \c -> do negError `fmap` c_lo_truncate c fd (fromIntegral size) -- | Closes a large object descriptor. Any large object descriptors that -- remain open at the end of a transaction will be closed automatically. loClose :: Connection -> LoFd -> IO (Maybe ()) loClose connection (LoFd fd) = withConn connection $ \c -> do negError `fmap` c_lo_close c fd -- | Removes a large object from the database. loUnlink :: Connection -> Oid -> IO (Maybe ()) loUnlink connection oid = withConn connection $ \c -> do negError `fmap` c_lo_unlink c oid foreign import ccall "libpq-fe.h PQconnectdb" c_PQconnectdb :: CString ->IO (Ptr PGconn) foreign import ccall "libpq-fe.h PQconnectStart" c_PQconnectStart :: CString ->IO (Ptr PGconn) foreign import ccall "libpq-fe.h PQconnectPoll" c_PQconnectPoll :: Ptr PGconn ->IO CInt foreign import ccall unsafe "libpq-fe.h PQdb" c_PQdb :: Ptr PGconn -> IO CString foreign import ccall unsafe "libpq-fe.h PQuser" c_PQuser :: Ptr PGconn -> IO CString foreign import ccall unsafe "libpq-fe.h PQpass" c_PQpass :: Ptr PGconn -> IO CString foreign import ccall unsafe "libpq-fe.h PQhost" c_PQhost :: Ptr PGconn -> IO CString foreign import ccall unsafe "libpq-fe.h PQport" c_PQport :: Ptr PGconn -> IO CString foreign import ccall unsafe "libpq-fe.h PQoptions" c_PQoptions :: Ptr PGconn -> IO CString foreign import ccall unsafe "libpq-fe.h PQbackendPID" c_PQbackendPID :: Ptr PGconn -> IO CInt foreign import ccall unsafe "libpq-fe.h PQconnectionNeedsPassword" c_PQconnectionNeedsPassword :: Ptr PGconn -> IO CInt foreign import ccall unsafe "libpq-fe.h PQconnectionUsedPassword" c_PQconnectionUsedPassword :: Ptr PGconn -> IO CInt foreign import ccall unsafe "libpq-fe.h PQstatus" c_PQstatus :: Ptr PGconn -> IO CInt foreign import ccall unsafe "libpq-fe.h PQtransactionStatus" c_PQtransactionStatus :: Ptr PGconn -> IO CInt foreign import ccall "libpq-fe.h PQparameterStatus" c_PQparameterStatus :: Ptr PGconn -> CString -> IO CString foreign import ccall unsafe "libpq-fe.h PQprotocolVersion" c_PQprotocolVersion :: Ptr PGconn -> IO CInt foreign import ccall unsafe "libpq-fe.h PQserverVersion" c_PQserverVersion :: Ptr PGconn -> IO CInt foreign import ccall unsafe "libpq-fe.h PQsocket" c_PQsocket :: Ptr PGconn -> IO CInt foreign import ccall "libpq-fe.h PQerrorMessage" c_PQerrorMessage :: Ptr PGconn -> IO CString {-# LINE 2316 "Database/PostgreSQL/LibPQ.hsc" #-} foreign import ccall "libpq-fe.h PQfinish" c_PQfinish :: Ptr PGconn -> IO () {-# LINE 2322 "Database/PostgreSQL/LibPQ.hsc" #-} foreign import ccall "libpq-fe.h PQreset" c_PQreset :: Ptr PGconn -> IO () foreign import ccall "libpq-fe.h PQresetStart" c_PQresetStart :: Ptr PGconn ->IO CInt foreign import ccall "libpq-fe.h PQresetPoll" c_PQresetPoll :: Ptr PGconn ->IO CInt foreign import ccall unsafe "libpq-fe.h PQclientEncoding" c_PQclientEncoding :: Ptr PGconn -> IO CInt foreign import ccall "libpq-fe.h pg_encoding_to_char" c_pg_encoding_to_char :: CInt -> IO CString foreign import ccall "libpq-fe.h PQsetClientEncoding" c_PQsetClientEncoding :: Ptr PGconn -> CString -> IO CInt type PGVerbosity = CInt foreign import ccall unsafe "libpq-fe.h PQsetErrorVerbosity" c_PQsetErrorVerbosity :: Ptr PGconn -> PGVerbosity -> IO PGVerbosity foreign import ccall "libpq-fe.h PQputCopyData" c_PQputCopyData :: Ptr PGconn -> Ptr CChar -> CInt -> IO CInt foreign import ccall "libpq-fe.h PQputCopyEnd" c_PQputCopyEnd :: Ptr PGconn -> CString -> IO CInt foreign import ccall "libpq-fe.h PQgetCopyData" c_PQgetCopyData :: Ptr PGconn -> Ptr (Ptr Word8) -> CInt -> IO CInt foreign import ccall "libpq-fe.h PQsendQuery" c_PQsendQuery :: Ptr PGconn -> CString ->IO CInt foreign import ccall "libpq-fe.h PQsendQueryParams" c_PQsendQueryParams :: Ptr PGconn -> CString -> CInt -> Ptr Oid -> Ptr CString -> Ptr CInt -> Ptr CInt -> CInt -> IO CInt foreign import ccall "libpq-fe.h PQsendPrepare" c_PQsendPrepare :: Ptr PGconn -> CString -> CString -> CInt -> Ptr Oid -> IO CInt foreign import ccall "libpq-fe.h PQsendQueryPrepared" c_PQsendQueryPrepared :: Ptr PGconn -> CString -> CInt -> Ptr CString -> Ptr CInt -> Ptr CInt -> CInt -> IO CInt foreign import ccall "libpq-fe.h PQsendDescribePrepared" c_PQsendDescribePrepared :: Ptr PGconn -> CString -> IO CInt foreign import ccall "libpq-fe.h PQsendDescribePortal" c_PQsendDescribePortal :: Ptr PGconn -> CString -> IO CInt foreign import ccall "libpq-fe.h PQflush" c_PQflush :: Ptr PGconn -> IO CInt foreign import ccall "libpq-fe.h PQgetCancel" c_PQgetCancel :: Ptr PGconn -> IO (Ptr PGcancel) foreign import ccall "libpq-fe.h &PQfreeCancel" p_PQfreeCancel :: FunPtr (Ptr PGcancel -> IO ()) foreign import ccall "libpq-fe.h PQcancel" c_PQcancel :: Ptr PGcancel -> CString -> CInt -> IO CInt foreign import ccall unsafe "libpq-fe.h PQnotifies" c_PQnotifies :: Ptr PGconn -> IO (Ptr Notify) foreign import ccall unsafe "libpq-fe.h PQconsumeInput" c_PQconsumeInput :: Ptr PGconn -> IO CInt foreign import ccall "libpq-fe.h PQisBusy" c_PQisBusy :: Ptr PGconn -> IO CInt foreign import ccall "libpq-fe.h PQsetnonblocking" c_PQsetnonblocking :: Ptr PGconn -> CInt -> IO CInt foreign import ccall unsafe "libpq-fe.h PQisnonblocking" c_PQisnonblocking :: Ptr PGconn -> IO CInt foreign import ccall "libpq-fe.h PQgetResult" c_PQgetResult :: Ptr PGconn -> IO (Ptr PGresult) foreign import ccall "libpq-fe.h PQexec" c_PQexec :: Ptr PGconn -> CString -> IO (Ptr PGresult) foreign import ccall "libpq-fe.h PQexecParams" c_PQexecParams :: Ptr PGconn -> CString -> CInt -> Ptr Oid -> Ptr CString -> Ptr CInt -> Ptr CInt -> CInt -> IO (Ptr PGresult) foreign import ccall "libpq-fe.h PQprepare" c_PQprepare :: Ptr PGconn -> CString -> CString -> CInt -> Ptr Oid -> IO (Ptr PGresult) foreign import ccall "libpq-fe.h PQexecPrepared" c_PQexecPrepared :: Ptr PGconn -> CString -> CInt -> Ptr CString -> Ptr CInt -> Ptr CInt -> CInt -> IO (Ptr PGresult) foreign import ccall "libpq-fe.h PQdescribePrepared" c_PQdescribePrepared :: Ptr PGconn -> CString -> IO (Ptr PGresult) foreign import ccall "libpq-fe.h PQdescribePortal" c_PQdescribePortal :: Ptr PGconn -> CString -> IO (Ptr PGresult) foreign import ccall "libpq-fe.h &PQclear" p_PQclear :: FunPtr (Ptr PGresult ->IO ()) foreign import ccall unsafe "libpq-fe.h PQresultStatus" c_PQresultStatus :: Ptr PGresult -> IO CInt foreign import ccall unsafe "libpq-fe.h PQresStatus" c_PQresStatus :: CInt -> IO CString foreign import ccall unsafe "libpq-fe.h PQresultErrorMessage" c_PQresultErrorMessage :: Ptr PGresult -> IO CString foreign import ccall "libpq-fe.h PQresultErrorField" c_PQresultErrorField :: Ptr PGresult -> CInt -> IO CString foreign import ccall unsafe "libpq-fe.h PQntuples" c_PQntuples :: Ptr PGresult -> CInt foreign import ccall unsafe "libpq-fe.h PQnfields" c_PQnfields :: Ptr PGresult -> CInt foreign import ccall unsafe "libpq-fe.h PQfname" c_PQfname :: Ptr PGresult -> CInt -> IO CString foreign import ccall unsafe "libpq-fe.h PQfnumber" c_PQfnumber :: Ptr PGresult -> CString -> IO CInt foreign import ccall unsafe "libpq-fe.h PQftable" c_PQftable :: Ptr PGresult -> CInt -> IO Oid foreign import ccall unsafe "libpq-fe.h PQftablecol" c_PQftablecol :: Ptr PGresult -> CInt -> IO CInt foreign import ccall unsafe "libpq-fe.h PQfformat" c_PQfformat :: Ptr PGresult -> CInt -> IO CInt foreign import ccall unsafe "libpq-fe.h PQftype" c_PQftype :: Ptr PGresult -> CInt -> IO Oid foreign import ccall unsafe "libpq-fe.h PQfmod" c_PQfmod :: Ptr PGresult -> CInt -> IO CInt foreign import ccall unsafe "libpq-fe.h PQfsize" c_PQfsize :: Ptr PGresult -> CInt -> IO CInt foreign import ccall unsafe "libpq-fe.h PQgetvalue" c_PQgetvalue :: Ptr PGresult -> CInt -> CInt -> IO CString foreign import ccall unsafe "libpq-fe.h PQgetisnull" c_PQgetisnull :: Ptr PGresult -> CInt -> CInt -> IO CInt foreign import ccall unsafe "libpq-fe.h PQgetlength" c_PQgetlength :: Ptr PGresult -> CInt -> CInt -> IO CInt foreign import ccall unsafe "libpq-fe.h PQnparams" c_PQnparams :: Ptr PGresult -> IO CInt foreign import ccall unsafe "libpq-fe.h PQparamtype" c_PQparamtype :: Ptr PGresult -> CInt -> IO Oid foreign import ccall unsafe "libpq-fe.h PQcmdStatus" c_PQcmdStatus :: Ptr PGresult -> IO CString foreign import ccall unsafe "libpq-fe.h PQcmdTuples" c_PQcmdTuples :: Ptr PGresult -> IO CString foreign import ccall unsafe "libpq-fe.h PQoidValue" c_PQoidValue :: Ptr PGresult -> IO Oid foreign import ccall "libpq-fe.h PQescapeStringConn" c_PQescapeStringConn :: Ptr PGconn -> Ptr Word8 -- Actually (CString) -> CString -> CSize -> Ptr CInt -> IO CSize foreign import ccall "libpq-fe.h PQescapeByteaConn" c_PQescapeByteaConn :: Ptr PGconn -> CString -- Actually (Ptr CUChar) -> CSize -> Ptr CSize -> IO (Ptr Word8) -- Actually (IO (Ptr CUChar)) foreign import ccall "libpq-fe.h PQunescapeBytea" c_PQunescapeBytea :: CString -- Actually (Ptr CUChar) -> Ptr CSize -> IO (Ptr Word8) -- Actually (IO (Ptr CUChar)) foreign import ccall unsafe "libpq-fe.h &PQfreemem" p_PQfreemem :: FunPtr (Ptr a -> IO ()) foreign import ccall unsafe "libpq-fe.h PQfreemem" c_PQfreemem :: Ptr a -> IO () type CFd = CInt foreign import ccall "libpq-fs.h lo_creat" c_lo_creat :: Ptr PGconn -> CInt -> IO Oid foreign import ccall "libpq-fs.h lo_create" c_lo_create :: Ptr PGconn -> Oid -> IO Oid foreign import ccall "libpq-fs.h lo_import" c_lo_import :: Ptr PGconn -> CString -> IO Oid foreign import ccall "libpq-fs.h lo_import_with_oid" c_lo_import_with_oid :: Ptr PGconn -> CString -> Oid -> IO Oid foreign import ccall "libpq-fs.h lo_export" c_lo_export :: Ptr PGconn -> Oid -> CString -> IO CInt foreign import ccall "libpq-fs.h lo_open" c_lo_open :: Ptr PGconn -> Oid -> CInt -> IO CFd foreign import ccall "libpq-fs.h lo_write" c_lo_write :: Ptr PGconn -> CFd -> CString -> CSize -> IO CInt foreign import ccall "libpq-fs.h lo_read" c_lo_read :: Ptr PGconn -> CFd -> Ptr Word8 -> CSize -> IO CInt foreign import ccall "libpq-fs.h lo_lseek" c_lo_lseek :: Ptr PGconn -> CFd -> CInt -> CInt -> IO CInt foreign import ccall "libpq-fs.h lo_tell" c_lo_tell :: Ptr PGconn -> CFd -> IO CInt foreign import ccall "libpq-fs.h lo_truncate" c_lo_truncate :: Ptr PGconn -> CFd -> CSize -> IO CInt foreign import ccall "libpq-fs.h lo_close" c_lo_close :: Ptr PGconn -> CFd -> IO CInt foreign import ccall "libpq-fs.h lo_unlink" c_lo_unlink :: Ptr PGconn -> Oid -> IO CInt