-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Concurrent DNS cache
--   
--   Concurrent DNS cache
@package concurrent-dns-cache
@version 0.1.3


-- | DNS cache to resolve domains concurrently.
module Network.DNS.Cache

-- | Configuration for DNS cache.
data DNSCacheConf
DNSCacheConf :: [ResolvConf] -> Int -> NominalDiffTime -> NominalDiffTime -> NominalDiffTime -> DNSCacheConf

-- | A list of resolvers (cache DNS servers). A domain is resolved by the
--   resolvers concurrently. The first reply is used regardless of
--   success/failure at this moment
[resolvConfs] :: DNSCacheConf -> [ResolvConf]

-- | Capability of how many domains can be resolved concurrently
[maxConcurrency] :: DNSCacheConf -> Int

-- | The minimum bound of cache duration for success replies in seconds.
[minTTL] :: DNSCacheConf -> NominalDiffTime

-- | The maximum bound of cache duration for success replies in seconds.
[maxTTL] :: DNSCacheConf -> NominalDiffTime

-- | The cache duration for failure replies in seconds.
[negativeTTL] :: DNSCacheConf -> NominalDiffTime

-- | An abstract data for DNS cache. Cached domains are expired every 10
--   seconds according to their TTL.
data DNSCache

-- | A basic function to create DNS cache. Domains should be resolved in
--   the function of the second argument.
withDNSCache :: (MonadBaseControl IO m, MonadIO m) => DNSCacheConf -> (DNSCache -> m a) -> m a

-- | Lookup <a>Domain</a> in the cache. If not exist, queries are sent to
--   DNS servers and resolved IP addresses are cached.
lookup :: DNSCache -> Domain -> IO (Maybe HostAddress)

-- | Lookup <a>Domain</a> only in the cache.
lookupCache :: DNSCache -> Domain -> IO (Maybe HostAddress)

-- | Information of positive result.
data Result

-- | An address obtained from the cache.
Hit :: HostAddress -> Result

-- | An address resolved from cache DNS servers.
Resolved :: HostAddress -> Result

-- | Specified domain is IP address. So, it is converted into a numeric
--   address.
Numeric :: HostAddress -> Result

-- | Lookup <a>Domain</a> in the cache. If not exist, queries are sent to
--   DNS servers and resolved IP addresses are cached.
resolve :: DNSCache -> Domain -> IO (Either DNSError Result)

-- | Lookup <a>Domain</a> only in the cache.
resolveCache :: DNSCache -> Domain -> IO (Maybe (Either DNSError Result))

-- | Wait until the predicate in the second argument is satisfied. The
--   predicate are given the number of the current resolving domains.
--   
--   For instance, if you ensure that no resolvings are going on:
--   
--   <pre>
--   wait cache (== 0)
--   </pre>
--   
--   If you want to ensure that capability of concurrent resolving is not
--   full:
--   
--   <pre>
--   wait cache (&lt; maxCon)
--   </pre>
--   
--   where <tt>maxCon</tt> represents <a>maxConcurrency</a> in
--   <a>DNSCacheConf</a>.
wait :: DNSCache -> (Int -> Bool) -> IO ()