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/*
* Copyright (C) 2014 Michal Ratajsky <michal.ratajsky@gmail.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the licence, 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <glib.h>
#include <glib-object.h>
#include <gmodule.h>
#include "matemixer.h"
#include "matemixer-private.h"
#include "matemixer-backend-module.h"
/**
* SECTION:matemixer
* @short_description: Library initialization and support functions
* @include: libmatemixer/matemixer.h
* @see_also: #MateMixerContext
*
* The libmatemixer library must be initialized before it is used by an
* application. The initialization function loads dynamic modules which provide
* access to sound systems (also called backends) and it only succeeds if there
* is at least one usable module present on the target system.
*
* To connect to a sound system and access the mixer functionality after the
* library is initialized, create a #MateMixerContext using the
* mate_mixer_context_new() function.
*/
static void load_modules (void);
static gint compare_modules (gconstpointer a,
gconstpointer b);
static GList *modules = NULL;
static gboolean initialized = FALSE;
/**
* mate_mixer_init:
*
* Initializes the library. You must call this function before using any other
* function from the library.
*
* Returns: %TRUE on success or %FALSE if the library installation does not
* provide support for any sound system backends.
*/
gboolean
mate_mixer_init (void)
{
if (initialized == TRUE)
return TRUE;
load_modules ();
if (modules != NULL) {
GList *list = modules;
while (list != NULL) {
GTypeModule *module = G_TYPE_MODULE (list->data);
GList *next = list->next;
/* Load the plugin and remove it from the list if it fails */
if (g_type_module_use (module) == FALSE) {
g_object_unref (module);
modules = g_list_delete_link (modules, list);
}
list = next;
}
if (modules != NULL) {
/* Sort the usable modules by priority */
modules = g_list_sort (modules, compare_modules);
initialized = TRUE;
} else
g_critical ("No usable backend modules have been found");
} else
g_critical ("No backend modules have been found");
return initialized;
}
/**
* mate_mixer_is_initialized:
*
* Returns %TRUE if the library has been initialized.
*
* Returns: %TRUE or %FALSE.
*/
gboolean
mate_mixer_is_initialized (void)
{
return initialized;
}
/**
* _mate_mixer_list_modules:
*
* Gets a list of loaded backend modules.
*
* Returns: a #GList.
*/
const GList *
_mate_mixer_list_modules (void)
{
return (const GList *) modules;
}
/**
* _mate_mixer_create_channel_mask:
* @positions: an array of channel positions
* @n: number of channel positions in the array
*
* Creates a channel mask using the given list of channel positions.
*
* Returns: a channel mask.
*/
guint32
_mate_mixer_create_channel_mask (MateMixerChannelPosition *positions, guint n)
{
guint32 mask = 0;
guint i = 0;
for (i = 0; i < n; i++) {
if (positions[i] > MATE_MIXER_CHANNEL_UNKNOWN &&
positions[i] < MATE_MIXER_CHANNEL_MAX)
mask |= 1 << positions[i];
}
return mask;
}
static void
load_modules (void)
{
static gboolean loaded = FALSE;
if (loaded == TRUE)
return;
if G_LIKELY (g_module_supported () == TRUE) {
GDir *dir;
GError *error = NULL;
/* Read the directory which contains module libraries and create a list
* of those that are likely to be usable backend modules */
dir = g_dir_open (LIBMATEMIXER_BACKEND_DIR, 0, &error);
if (dir != NULL) {
const gchar *name;
while ((name = g_dir_read_name (dir)) != NULL) {
gchar *file;
if (g_str_has_suffix (name, "." G_MODULE_SUFFIX) == FALSE)
continue;
file = g_build_filename (LIBMATEMIXER_BACKEND_DIR, name, NULL);
modules = g_list_prepend (modules,
mate_mixer_backend_module_new (file));
g_free (file);
}
g_dir_close (dir);
} else {
g_critical ("%s", error->message);
g_error_free (error);
}
} else {
g_critical ("Unable to load backend modules: Not supported");
}
loaded = TRUE;
}
/* Backend modules sorting function, higher priority number means higher priority
* of the backend module */
static gint
compare_modules (gconstpointer a, gconstpointer b)
{
const MateMixerBackendInfo *info1, *info2;
info1 = mate_mixer_backend_module_get_info (MATE_MIXER_BACKEND_MODULE (a));
info2 = mate_mixer_backend_module_get_info (MATE_MIXER_BACKEND_MODULE (b));
return info2->priority - info1->priority;
}
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