gstreamer/gst/gstplugin.h
Sebastian Dröge 18a7a1d062 gst: Add better support for static plugins
API: GST_PLUGIN_STATIC_DECLARE()
API: GST_PLUGIN_STATIC_REGISTER()

Based on a patch by Håvard Graff <havard.graff@tandberg.com>.

This now allows GST_PLUGIN_DEFINE() to create a static plugin if
GST_PLUGIN_BUILD_STATIC is defined. The resulting plugin can be
statically linked or dynamically linked during compilation but
can't be dynamically loaded during runtime.

Also adds GST_PLUGIN_STATIC_DECLARE() and GST_PLUGIN_STATIC_REGISTER(),
which allows to register a static linked plugin easily.
It is still required to manually register every single statically linked
plugin from inside the application as this can't be automated in a portable
way.

A new configure parameter --enable-static-plugins was added that allows
to build all plugins we build here as static plugins.

Fixes bug #667305.
2013-04-15 15:52:18 +02:00

358 lines
14 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstplugin.h: Header for plugin subsystem
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef __GST_PLUGIN_H__
#define __GST_PLUGIN_H__
#include <gst/gstconfig.h>
#include <gst/gstobject.h>
#include <gst/gstmacros.h>
#include <gst/gststructure.h>
G_BEGIN_DECLS
/**
* GstPlugin:
*
* The opaque plugin object
*/
typedef struct _GstPlugin GstPlugin;
typedef struct _GstPluginClass GstPluginClass;
typedef struct _GstPluginDesc GstPluginDesc;
/**
* gst_plugin_error_quark:
*
* Get the error quark.
*
* Returns: The error quark used in GError messages
*/
GQuark gst_plugin_error_quark (void);
/**
* GST_PLUGIN_ERROR:
*
* The error message category quark
*/
#define GST_PLUGIN_ERROR gst_plugin_error_quark ()
/**
* GstPluginError:
* @GST_PLUGIN_ERROR_MODULE: The plugin could not be loaded
* @GST_PLUGIN_ERROR_DEPENDENCIES: The plugin has unresolved dependencies
* @GST_PLUGIN_ERROR_NAME_MISMATCH: The plugin has already be loaded from a different file
*
* The plugin loading errors
*/
typedef enum
{
GST_PLUGIN_ERROR_MODULE,
GST_PLUGIN_ERROR_DEPENDENCIES,
GST_PLUGIN_ERROR_NAME_MISMATCH
} GstPluginError;
/**
* GstPluginFlags:
* @GST_PLUGIN_FLAG_CACHED: Temporarily loaded plugins
* @GST_PLUGIN_FLAG_BLACKLISTED: The plugin won't be scanned (again)
*
* The plugin loading state
*/
typedef enum
{
GST_PLUGIN_FLAG_CACHED = (GST_OBJECT_FLAG_LAST << 0),
GST_PLUGIN_FLAG_BLACKLISTED = (GST_OBJECT_FLAG_LAST << 1)
} GstPluginFlags;
/**
* GstPluginDependencyFlags:
* @GST_PLUGIN_DEPENDENCY_FLAG_NONE : no special flags
* @GST_PLUGIN_DEPENDENCY_FLAG_RECURSE : recurse into subdirectories
* @GST_PLUGIN_DEPENDENCY_FLAG_PATHS_ARE_DEFAULT_ONLY : use paths
* argument only if none of the environment variables is set
* @GST_PLUGIN_DEPENDENCY_FLAG_FILE_NAME_IS_SUFFIX : interpret
* filename argument as filter suffix and check all matching files in
* the directory
*
* Flags used in connection with gst_plugin_add_dependency().
*/
typedef enum {
GST_PLUGIN_DEPENDENCY_FLAG_NONE = 0,
GST_PLUGIN_DEPENDENCY_FLAG_RECURSE = (1 << 0),
GST_PLUGIN_DEPENDENCY_FLAG_PATHS_ARE_DEFAULT_ONLY = (1 << 1),
GST_PLUGIN_DEPENDENCY_FLAG_FILE_NAME_IS_SUFFIX = (1 << 2)
} GstPluginDependencyFlags;
/**
* GstPluginInitFunc:
* @plugin: The plugin object
*
* A plugin should provide a pointer to a function of this type in the
* plugin_desc struct.
* This function will be called by the loader at startup. One would then
* register each #GstPluginFeature.
*
* Returns: %TRUE if plugin initialised successfully
*/
/* FIXME 0.11: Make return void */
typedef gboolean (*GstPluginInitFunc) (GstPlugin *plugin);
/**
* GstPluginInitFullFunc:
* @plugin: The plugin object
* @user_data: extra data
*
* A plugin should provide a pointer to a function of either #GstPluginInitFunc
* or this type in the plugin_desc struct.
* The function will be called by the loader at startup. One would then
* register each #GstPluginFeature. This version allows
* user data to be passed to init function (useful for bindings).
*
* Returns: %TRUE if plugin initialised successfully
*/
/* FIXME 0.11: Merge with GstPluginInitFunc */
typedef gboolean (*GstPluginInitFullFunc) (GstPlugin *plugin, gpointer user_data);
/**
* GstPluginDesc:
* @major_version: the major version number of core that plugin was compiled for
* @minor_version: the minor version number of core that plugin was compiled for
* @name: a unique name of the plugin
* @description: description of plugin
* @plugin_init: pointer to the init function of this plugin.
* @version: version of the plugin
* @license: effective license of plugin
* @source: source module plugin belongs to
* @package: shipped package plugin belongs to
* @origin: URL to provider of plugin
* @release_datetime: date time string in ISO 8601 format (or rather, a
* subset thereof), or NULL. Allowed are the following formats:
* "YYYY-MM-DD" and "YYY-MM-DDTHH:MMZ" (with 'T' a separator and 'Z'
* indicating UTC/Zulu time). This field should be set via the
* GST_PACKAGE_RELEASE_DATETIME preprocessor macro.
*
* A plugin should export a variable of this type called plugin_desc. The plugin
* loader will use the data provided there to initialize the plugin.
*
* The @licence parameter must be one of: LGPL, GPL, QPL, GPL/QPL, MPL,
* BSD, MIT/X11, Proprietary, unknown.
*/
struct _GstPluginDesc {
gint major_version;
gint minor_version;
const gchar *name;
const gchar *description;
GstPluginInitFunc plugin_init;
const gchar *version;
const gchar *license;
const gchar *source;
const gchar *package;
const gchar *origin;
const gchar *release_datetime;
/*< private >*/
gpointer _gst_reserved[GST_PADDING];
};
#define GST_TYPE_PLUGIN (gst_plugin_get_type())
#define GST_IS_PLUGIN(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_PLUGIN))
#define GST_IS_PLUGIN_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_PLUGIN))
#define GST_PLUGIN_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_PLUGIN, GstPluginClass))
#define GST_PLUGIN(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_PLUGIN, GstPlugin))
#define GST_PLUGIN_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_PLUGIN, GstPluginClass))
#define GST_PLUGIN_CAST(obj) ((GstPlugin*)(obj))
#ifdef GST_PACKAGE_RELEASE_DATETIME
#define __GST_PACKAGE_RELEASE_DATETIME GST_PACKAGE_RELEASE_DATETIME
#else
#define __GST_PACKAGE_RELEASE_DATETIME NULL
#endif
/**
* GST_PLUGIN_STATIC_DECLARE:
* @name: short, but unique name of the plugin
*
* This macro can be used to initialize statically linked plugins. It is
* necessary to call this macro before the plugin can be used.
* It has to be used in combination with GST_PLUGIN_STATIC_REGISTER
* and must be placed outside any block to declare the plugin initialization
* function.
*
* Since: 1.2.0
*/
#define GST_PLUGIN_STATIC_DECLARE(name) \
extern void G_PASTE(gst_plugin_, G_PASTE(name, _register)) (void)
/**
* GST_PLUGIN_STATIC_REGISTER:
* @name: short, but unique name of the plugin
*
* This macro can be used to initialize statically linked plugins. It is
* necessary to call this macro before the plugin can be used.
* It has to be used in combination with GST_PLUGIN_STATIC_DECLARE and
* calls the plugin initialization function.
*
* Since: 1.2.0
*/
#define GST_PLUGIN_STATIC_REGISTER(name) G_PASTE(gst_plugin_, G_PASTE(name, _register)) ()
/**
* GST_PLUGIN_DEFINE:
* @major: major version number of the gstreamer-core that plugin was compiled for
* @minor: minor version number of the gstreamer-core that plugin was compiled for
* @name: short, but unique name of the plugin
* @description: information about the purpose of the plugin
* @init: function pointer to the plugin_init method with the signature of <code>static gboolean plugin_init (GstPlugin * plugin)</code>.
* @version: full version string (e.g. VERSION from config.h)
* @license: under which licence the package has been released, e.g. GPL, LGPL.
* @package: the package-name (e.g. PACKAGE_NAME from config.h)
* @origin: a description from where the package comes from (e.g. the homepage URL)
*
* This macro needs to be used to define the entry point and meta data of a
* plugin. One would use this macro to export a plugin, so that it can be used
* by other applications.
*
* The macro uses a define named PACKAGE for the #GstPluginDesc,source field.
* When using autoconf, this is usually set automatically via the AC_INIT
* macro, and set in config.h. If you are not using autoconf, you will need to
* define PACKAGE yourself and set it to a short mnemonic string identifying
* your application/package, e.g. 'someapp' or 'my-plugins-foo.
*
* If defined, the GST_PACKAGE_RELEASE_DATETIME will also be used for the
* #GstPluginDesc,release_datetime field.
*/
#ifdef GST_PLUGIN_BUILD_STATIC
#define GST_PLUGIN_DEFINE(major,minor,name,description,init,version,license,package,origin) \
G_BEGIN_DECLS \
GST_PLUGIN_EXPORT void G_PASTE(gst_plugin_, G_PASTE(name, _register)) (void); \
\
void \
G_PASTE(gst_plugin_, G_PASTE(name, _register)) (void) \
{ \
gst_plugin_register_static (major, minor, G_STRINGIFY(name), \
description, init, version, license, \
PACKAGE, package, origin); \
} \
G_END_DECLS
#else /* !GST_PLUGIN_BUILD_STATIC */
#define GST_PLUGIN_DEFINE(major,minor,name,description,init,version,license,package,origin) \
G_BEGIN_DECLS \
GST_PLUGIN_EXPORT GstPluginDesc gst_plugin_desc = { \
major, \
minor, \
G_STRINGIFY(name), \
(gchar *) description, \
init, \
version, \
license, \
PACKAGE, \
package, \
origin, \
__GST_PACKAGE_RELEASE_DATETIME, \
GST_PADDING_INIT \
}; \
G_END_DECLS
#endif /* GST_PLUGIN_BUILD_STATIC */
/**
* GST_LICENSE_UNKNOWN:
*
* To be used in GST_PLUGIN_DEFINE if usure about the licence.
*/
#define GST_LICENSE_UNKNOWN "unknown"
/* function for filters */
/**
* GstPluginFilter:
* @plugin: the plugin to check
* @user_data: the user_data that has been passed on e.g. gst_registry_plugin_filter()
*
* A function that can be used with e.g. gst_registry_plugin_filter()
* to get a list of plugins that match certain criteria.
*
* Returns: TRUE for a positive match, FALSE otherwise
*/
typedef gboolean (*GstPluginFilter) (GstPlugin *plugin,
gpointer user_data);
GType gst_plugin_get_type (void);
gboolean gst_plugin_register_static (gint major_version,
gint minor_version,
const gchar *name,
const gchar *description,
GstPluginInitFunc init_func,
const gchar *version,
const gchar *license,
const gchar *source,
const gchar *package,
const gchar *origin);
gboolean gst_plugin_register_static_full (gint major_version,
gint minor_version,
const gchar *name,
const gchar *description,
GstPluginInitFullFunc init_full_func,
const gchar *version,
const gchar *license,
const gchar *source,
const gchar *package,
const gchar *origin,
gpointer user_data);
const gchar* gst_plugin_get_name (GstPlugin *plugin);
const gchar* gst_plugin_get_description (GstPlugin *plugin);
const gchar* gst_plugin_get_filename (GstPlugin *plugin);
const gchar* gst_plugin_get_version (GstPlugin *plugin);
const gchar* gst_plugin_get_license (GstPlugin *plugin);
const gchar* gst_plugin_get_source (GstPlugin *plugin);
const gchar* gst_plugin_get_package (GstPlugin *plugin);
const gchar* gst_plugin_get_origin (GstPlugin *plugin);
const gchar* gst_plugin_get_release_date_string (GstPlugin *plugin);
const GstStructure* gst_plugin_get_cache_data (GstPlugin * plugin);
void gst_plugin_set_cache_data (GstPlugin * plugin, GstStructure *cache_data);
gboolean gst_plugin_is_loaded (GstPlugin *plugin);
GstPlugin * gst_plugin_load_file (const gchar *filename, GError** error);
GstPlugin * gst_plugin_load (GstPlugin *plugin);
GstPlugin * gst_plugin_load_by_name (const gchar *name);
void gst_plugin_add_dependency (GstPlugin * plugin,
const gchar ** env_vars,
const gchar ** paths,
const gchar ** names,
GstPluginDependencyFlags flags);
void gst_plugin_add_dependency_simple (GstPlugin * plugin,
const gchar * env_vars,
const gchar * paths,
const gchar * names,
GstPluginDependencyFlags flags);
void gst_plugin_list_free (GList *list);
G_END_DECLS
#endif /* __GST_PLUGIN_H__ */