GI.Gst.Objects.Registry

One registry holds the metadata of a set of plugins.

<emphasis role="bold">Design:</emphasis>

The Registry object is a list of plugins and some functions for dealing with them. Each Plugin is matched 1-1 with a file on disk, and may or may not be loaded at a given time.

The primary source, at all times, of plugin information is each plugin file itself. Thus, if an application wants information about a particular plugin, or wants to search for a feature that satisfies given criteria, the primary means of doing so is to load every plugin and look at the resulting information that is gathered in the default registry. Clearly, this is a time consuming process, so we cache information in the registry file. The format and location of the cache file is internal to gstreamer.

On startup, plugins are searched for in the plugin search path. The following locations are checked in this order: <itemizedlist> <listitem> <para>location from --gst-plugin-path commandline option.</para> </listitem> <listitem> <para>the GST_PLUGIN_PATH environment variable.</para> </listitem> <listitem> <para>the GST_PLUGIN_SYSTEM_PATH environment variable.</para> </listitem> <listitem> <para>default locations (if GST_PLUGIN_SYSTEM_PATH is not set). Those default locations are: <filename>$XDG_DATA_HOME/gstreamer-$GST_API_VERSION/plugins/</filename> and <filename>$prefix/libs/gstreamer-$GST_API_VERSION/</filename>. <ulink url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html"> <filename>$XDG_DATA_HOME</filename></ulink> defaults to <filename>$HOME/.local/share</filename>. </para> </listitem> </itemizedlist> The registry cache file is loaded from <filename>$XDG_CACHE_HOME/gstreamer-$GST_API_VERSION/registry-$ARCH.bin</filename> (where <ulink url="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html"> <filename>$XDG_CACHE_HOME</filename></ulink> defaults to <filename>$HOME/.cache</filename>) or the file listed in the GST_REGISTRY env var. One reason to change the registry location is for testing.

For each plugin that is found in the plugin search path, there could be 3 possibilities for cached information: <itemizedlist> <listitem> <para>the cache may not contain information about a given file.</para> </listitem> <listitem> <para>the cache may have stale information.</para> </listitem> <listitem> <para>the cache may have current information.</para> </listitem> </itemizedlist>

In the first two cases, the plugin is loaded and the cache updated. In addition to these cases, the cache may have entries for plugins that are not relevant to the current process. These are marked as not available to the current process. If the cache is updated for whatever reason, it is marked dirty.

A dirty cache is written out at the end of initialization. Each entry is checked to make sure the information is minimally valid. If not, the entry is simply dropped.

<emphasis role="bold">Implementation notes:</emphasis>

The "cache" and "registry" are different concepts and can represent different sets of plugins. For various reasons, at init time, the cache is stored in the default registry, and plugins not relevant to the current process are marked with the PluginFlagsCached bit. These plugins are removed at the end of initialization.

Exported types

newtype Registry

Constructors

Registry (ManagedPtr Registry)

Instances

GObject Registry

Methods

gobjectType :: Registry -> IO GType

IsObject Registry

IsObject Registry

IsRegistry Registry

((~) * info (ResolveRegistryMethod t Registry), MethodInfo * info Registry p) => IsLabel t (Registry -> p)

Methods

fromLabel :: Proxy# Symbol t -> Registry -> p

((~) * info (ResolveRegistryMethod t Registry), MethodInfo * info Registry p) => IsLabelProxy t (Registry -> p)

Methods

fromLabelProxy :: Proxy Symbol t -> Registry -> p

HasAttributeList * Registry

type AttributeList Registry

type AttributeList Registry

type SignalList Registry

type SignalList Registry

class GObject o => IsRegistry o

Instances

(GObject a, UnknownAncestorError Constraint Registry a) => IsRegistry a

IsRegistry Registry

toRegistry :: IsRegistry o => o -> IO Registry

noRegistry :: Maybe Registry

Methods

addFeature

data RegistryAddFeatureMethodInfo

Instances

((~) * signature (b -> m Bool), MonadIO m, IsRegistry a, IsPluginFeature b) => MethodInfo * RegistryAddFeatureMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryAddFeatureMethodInfo a -> signature -> s

registryAddFeature

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a, IsPluginFeature b)

=> a

registry: the registry to add the plugin to

-> b

feature: the feature to add

-> m Bool

Returns: True on success.

MT safe.

Add the feature to the registry. The feature-added signal will be emitted. This function sinks feature.

addPlugin

data RegistryAddPluginMethodInfo

Instances

((~) * signature (b -> m Bool), MonadIO m, IsRegistry a, IsPlugin b) => MethodInfo * RegistryAddPluginMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryAddPluginMethodInfo a -> signature -> s

registryAddPlugin

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a, IsPlugin b)

=> a

registry: the registry to add the plugin to

-> b

plugin: the plugin to add

-> m Bool

Returns: True on success.

MT safe.

Add the plugin to the registry. The plugin-added signal will be emitted. This function will sink plugin.

checkFeatureVersion

data RegistryCheckFeatureVersionMethodInfo

Instances

((~) * signature (Text -> Word32 -> Word32 -> Word32 -> m Bool), MonadIO m, IsRegistry a) => MethodInfo * RegistryCheckFeatureVersionMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryCheckFeatureVersionMethodInfo a -> signature -> s

registryCheckFeatureVersion

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: a Registry

-> Text

featureName: the name of the feature (e.g. "oggdemux")

-> Word32

minMajor: the minimum major version number

-> Word32

minMinor: the minimum minor version number

-> Word32

minMicro: the minimum micro version number

-> m Bool

Returns: True if the feature could be found and the version is the same as the required version or newer, and False otherwise.

Checks whether a plugin feature by the given name exists in registry and whether its version is at least the version required.

featureFilter

data RegistryFeatureFilterMethodInfo

Instances

((~) * signature (PluginFeatureFilter -> Bool -> m [PluginFeature]), MonadIO m, IsRegistry a) => MethodInfo * RegistryFeatureFilterMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryFeatureFilterMethodInfo a -> signature -> s

registryFeatureFilter

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: registry to query

-> PluginFeatureFilter

filter: the filter to use

-> Bool

first: only return first match

-> m [PluginFeature]

Returns: a List of PluginFeature. Use pluginFeatureListFree after usage.

MT safe.

Runs a filter against all features of the plugins in the registry and returns a GList with the results. If the first flag is set, only the first match is returned (as a list with a single object).

findFeature

data RegistryFindFeatureMethodInfo

Instances

((~) * signature (Text -> GType -> m (Maybe PluginFeature)), MonadIO m, IsRegistry a) => MethodInfo * RegistryFindFeatureMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryFindFeatureMethodInfo a -> signature -> s

registryFindFeature

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: the registry to search

-> Text

name: the pluginfeature name to find

-> GType

type: the pluginfeature type to find

-> m (Maybe PluginFeature)

Returns: the pluginfeature with the given name and type or Nothing if the plugin was not found. objectUnref after usage.

MT safe.

Find the pluginfeature with the given name and type in the registry.

findPlugin

data RegistryFindPluginMethodInfo

Instances

((~) * signature (Text -> m (Maybe Plugin)), MonadIO m, IsRegistry a) => MethodInfo * RegistryFindPluginMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryFindPluginMethodInfo a -> signature -> s

registryFindPlugin

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: the registry to search

-> Text

name: the plugin name to find

-> m (Maybe Plugin)

Returns: the plugin with the given name or Nothing if the plugin was not found. objectUnref after usage.

MT safe.

Find the plugin with the given name in the registry. The plugin will be reffed; caller is responsible for unreffing.

forkIsEnabled

registryForkIsEnabled

Arguments

:: (HasCallStack, MonadIO m)

=> m Bool

Returns: True if GStreamer will use the child helper process when rebuilding the registry.

By default GStreamer will perform scanning and rebuilding of the registry file using a helper child process.

Applications might want to disable this behaviour with the registryForkSetEnabled function, in which case new plugins are scanned (and loaded) into the application process.

forkSetEnabled

registryForkSetEnabled

Arguments

:: (HasCallStack, MonadIO m)

=> Bool

enabled: whether rebuilding the registry can use a temporary child helper process.

-> m ()

Applications might want to disable/enable spawning of a child helper process when rebuilding the registry. See registryForkIsEnabled for more information.

get

registryGet

Arguments

:: (HasCallStack, MonadIO m)

=> m Registry

Returns: the Registry.

Retrieves the singleton plugin registry. The caller does not own a reference on the registry, as it is alive as long as GStreamer is initialized.

getFeatureList

data RegistryGetFeatureListMethodInfo

Instances

((~) * signature (GType -> m [PluginFeature]), MonadIO m, IsRegistry a) => MethodInfo * RegistryGetFeatureListMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryGetFeatureListMethodInfo a -> signature -> s

registryGetFeatureList

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: a Registry

-> GType

type: a GType.

-> m [PluginFeature]

Returns: a List of PluginFeature of type. Use pluginFeatureListFree after use

MT safe.

Retrieves a List of PluginFeature of type.

getFeatureListByPlugin

data RegistryGetFeatureListByPluginMethodInfo

Instances

((~) * signature (Text -> m [PluginFeature]), MonadIO m, IsRegistry a) => MethodInfo * RegistryGetFeatureListByPluginMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryGetFeatureListByPluginMethodInfo a -> signature -> s

registryGetFeatureListByPlugin

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: a Registry.

-> Text

name: a plugin name.

-> m [PluginFeature]

Returns: a List of PluginFeature. Use pluginFeatureListFree after usage.

Retrieves a List of features of the plugin with name name.

getFeatureListCookie

data RegistryGetFeatureListCookieMethodInfo

Instances

((~) * signature (m Word32), MonadIO m, IsRegistry a) => MethodInfo * RegistryGetFeatureListCookieMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryGetFeatureListCookieMethodInfo a -> signature -> s

registryGetFeatureListCookie

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: the registry

-> m Word32

Returns: the feature list cookie.

Returns the registry's feature list cookie. This changes every time a feature is added or removed from the registry.

getPluginList

data RegistryGetPluginListMethodInfo

Instances

((~) * signature (m [Plugin]), MonadIO m, IsRegistry a) => MethodInfo * RegistryGetPluginListMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryGetPluginListMethodInfo a -> signature -> s

registryGetPluginList

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: the registry to search

-> m [Plugin]

Returns: a List of Plugin. Use pluginListFree after usage.

MT safe.

Get a copy of all plugins registered in the given registry. The refcount of each element in the list in incremented.

lookup

data RegistryLookupMethodInfo

Instances

((~) * signature (Text -> m (Maybe Plugin)), MonadIO m, IsRegistry a) => MethodInfo * RegistryLookupMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryLookupMethodInfo a -> signature -> s

registryLookup

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: the registry to look up in

-> Text

filename: the name of the file to look up

-> m (Maybe Plugin)

Returns: the Plugin if found, or Nothing if not. objectUnref after usage.

Look up a plugin in the given registry with the given filename. If found, plugin is reffed.

lookupFeature

data RegistryLookupFeatureMethodInfo

Instances

((~) * signature (Text -> m PluginFeature), MonadIO m, IsRegistry a) => MethodInfo * RegistryLookupFeatureMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryLookupFeatureMethodInfo a -> signature -> s

registryLookupFeature

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: a Registry

-> Text

name: a PluginFeature name

-> m PluginFeature

Returns: a PluginFeature with its refcount incremented, use objectUnref after usage.

MT safe.

Find a PluginFeature with name in registry.

pluginFilter

data RegistryPluginFilterMethodInfo

Instances

((~) * signature (PluginFilter -> Bool -> m [Plugin]), MonadIO m, IsRegistry a) => MethodInfo * RegistryPluginFilterMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryPluginFilterMethodInfo a -> signature -> s

registryPluginFilter

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: registry to query

-> PluginFilter

filter: the filter to use

-> Bool

first: only return first match

-> m [Plugin]

Returns: a List of Plugin. Use pluginListFree after usage.

MT safe.

Runs a filter against all plugins in the registry and returns a List with the results. If the first flag is set, only the first match is returned (as a list with a single object). Every plugin is reffed; use pluginListFree after use, which will unref again.

removeFeature

data RegistryRemoveFeatureMethodInfo

Instances

((~) * signature (b -> m ()), MonadIO m, IsRegistry a, IsPluginFeature b) => MethodInfo * RegistryRemoveFeatureMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryRemoveFeatureMethodInfo a -> signature -> s

registryRemoveFeature

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a, IsPluginFeature b)

=> a

registry: the registry to remove the feature from

-> b

feature: the feature to remove

-> m ()

Remove the feature from the registry.

MT safe.

removePlugin

data RegistryRemovePluginMethodInfo

Instances

((~) * signature (b -> m ()), MonadIO m, IsRegistry a, IsPlugin b) => MethodInfo * RegistryRemovePluginMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryRemovePluginMethodInfo a -> signature -> s

registryRemovePlugin

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a, IsPlugin b)

=> a

registry: the registry to remove the plugin from

-> b

plugin: the plugin to remove

-> m ()

Remove the plugin from the registry.

MT safe.

scanPath

data RegistryScanPathMethodInfo

Instances

((~) * signature (Text -> m Bool), MonadIO m, IsRegistry a) => MethodInfo * RegistryScanPathMethodInfo a signature

Methods

overloadedMethod :: MethodProxy RegistryScanPathMethodInfo a -> signature -> s

registryScanPath

Arguments

:: (HasCallStack, MonadIO m, IsRegistry a)

=> a

registry: the registry to add found plugins to

-> Text

path: the path to scan

-> m Bool

Returns: True if registry changed

Scan the given path for plugins to add to the registry. The syntax of the path is specific to the registry.

Signals

featureAdded

type C_RegistryFeatureAddedCallback = Ptr () -> Ptr PluginFeature -> Ptr () -> IO ()

type RegistryFeatureAddedCallback = PluginFeature -> IO ()

data RegistryFeatureAddedSignalInfo

Instances

SignalInfo RegistryFeatureAddedSignalInfo

Associated Types

type HaskellCallbackType RegistryFeatureAddedSignalInfo :: *

Methods

connectSignal :: GObject o => SignalProxy o RegistryFeatureAddedSignalInfo -> o -> HaskellCallbackType RegistryFeatureAddedSignalInfo -> SignalConnectMode -> IO SignalHandlerId

type HaskellCallbackType RegistryFeatureAddedSignalInfo

type HaskellCallbackType RegistryFeatureAddedSignalInfo = RegistryFeatureAddedCallback

afterRegistryFeatureAdded :: (GObject a, MonadIO m) => a -> RegistryFeatureAddedCallback -> m SignalHandlerId

genClosure_RegistryFeatureAdded :: RegistryFeatureAddedCallback -> IO Closure

mk_RegistryFeatureAddedCallback :: C_RegistryFeatureAddedCallback -> IO (FunPtr C_RegistryFeatureAddedCallback)

noRegistryFeatureAddedCallback :: Maybe RegistryFeatureAddedCallback

onRegistryFeatureAdded :: (GObject a, MonadIO m) => a -> RegistryFeatureAddedCallback -> m SignalHandlerId

wrap_RegistryFeatureAddedCallback :: RegistryFeatureAddedCallback -> Ptr () -> Ptr PluginFeature -> Ptr () -> IO ()

pluginAdded

type C_RegistryPluginAddedCallback = Ptr () -> Ptr Plugin -> Ptr () -> IO ()

type RegistryPluginAddedCallback = Plugin -> IO ()

data RegistryPluginAddedSignalInfo

Instances

SignalInfo RegistryPluginAddedSignalInfo

Associated Types

type HaskellCallbackType RegistryPluginAddedSignalInfo :: *

Methods

connectSignal :: GObject o => SignalProxy o RegistryPluginAddedSignalInfo -> o -> HaskellCallbackType RegistryPluginAddedSignalInfo -> SignalConnectMode -> IO SignalHandlerId

type HaskellCallbackType RegistryPluginAddedSignalInfo

type HaskellCallbackType RegistryPluginAddedSignalInfo = RegistryPluginAddedCallback

afterRegistryPluginAdded :: (GObject a, MonadIO m) => a -> RegistryPluginAddedCallback -> m SignalHandlerId

genClosure_RegistryPluginAdded :: RegistryPluginAddedCallback -> IO Closure

mk_RegistryPluginAddedCallback :: C_RegistryPluginAddedCallback -> IO (FunPtr C_RegistryPluginAddedCallback)

noRegistryPluginAddedCallback :: Maybe RegistryPluginAddedCallback

onRegistryPluginAdded :: (GObject a, MonadIO m) => a -> RegistryPluginAddedCallback -> m SignalHandlerId

wrap_RegistryPluginAddedCallback :: RegistryPluginAddedCallback -> Ptr () -> Ptr Plugin -> Ptr () -> IO ()