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Add _g_io_module_get_default(), use to simplify other *_get_default()s

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Add _g_io_module_get_default(), which implements the
figure-out-the-best-available-module-that-is-actually-usable logic,
and use that to simplify g_proxy_resolver_get_default(),
g_settings_backend_get_default(), g_tls_backend_get_default(), and
g_vfs_get_default().

https://bugzilla.gnome.org/show_bug.cgi?id=620932
This commit is contained in:
Dan Winship 2011-06-21 18:21:27 -04:00
parent 38d21f6d8a
commit 1481b7bca3
6 changed files with 161 additions and 174 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
gio/giomodule-priv.h
View File

@ -30,6 +30,11 @@ G_BEGIN_DECLS
void _g_io_modules_ensure_extension_points_registered (void);
void _g_io_modules_ensure_loaded (void);
typedef gboolean (*GIOModuleVerifyFunc) (gpointer);
gpointer _g_io_module_get_default (const gchar *extension_point,
const gchar *envvar,
GIOModuleVerifyFunc verify_func);
G_END_DECLS
#endif /* __G_IO_MODULE_PRIV_H__ */

127
gio/giomodule.c
View File

@ -630,6 +630,133 @@ g_io_modules_load_all_in_directory (const char *dirname)
return g_io_modules_load_all_in_directory_with_scope (dirname, NULL);
}
G_LOCK_DEFINE_STATIC (default_modules);
GHashTable *default_modules;
static gpointer
try_implementation (GIOExtension *extension,
GIOModuleVerifyFunc verify_func)
{
GType type = g_io_extension_get_type (extension);
gpointer impl;
if (g_type_is_a (type, G_TYPE_INITABLE))
return g_initable_new (type, NULL, NULL, NULL);
else
{
impl = g_object_new (type, NULL);
if (!verify_func || verify_func (impl))
return impl;
g_object_unref (impl);
return NULL;
}
}
/**
* _g_io_module_get_default:
* @extension_point: the name of an extension point
* @envvar: (allow-none): the name of an environment variable to
* override the default implementation.
* @verify_func: (allow-none): a function to call to verify that
* a given implementation is usable in the current environment.
*
* Retrieves the default object implementing @extension_point.
*
* If @envvar is not %NULL, and the environment variable with that
* name is set, then the implementation it specifies will be tried
* first. After that, or if @envvar is not set, all other
* implementations will be tried in order of decreasing priority.
*
* If an extension point implementation implements #GInitable, then
* that implementation will only be used if it initializes
* successfully. Otherwise, if @verify_func is not %NULL, then it will
* be called on each candidate implementation after construction, to
* check if it is actually usable or not.
*
* The result is cached after it is generated the first time, and
* the function is thread-safe.
*
* Return value: (transfer none): an object implementing
* @extension_point, or %NULL if there are no usable
* implementations.
*/
gpointer
_g_io_module_get_default (const gchar *extension_point,
const gchar *envvar,
GIOModuleVerifyFunc verify_func)
{
const char *use_this;
GList *l;
GIOExtensionPoint *ep;
GIOExtension *extension, *preferred;
gpointer impl;
G_LOCK (default_modules);
if (default_modules)
{
gpointer key;
if (g_hash_table_lookup_extended (default_modules, extension_point,
&key, &impl))
{
G_UNLOCK (default_modules);
return impl;
}
}
else
{
default_modules = g_hash_table_new (g_str_hash, g_str_equal);
}
_g_io_modules_ensure_loaded ();
ep = g_io_extension_point_lookup (extension_point);
if (!ep)
{
g_warn_if_reached ();
G_UNLOCK (default_modules);
return NULL;
}
use_this = envvar ? g_getenv (envvar) : NULL;
if (use_this)
{
preferred = g_io_extension_point_get_extension_by_name (ep, use_this);
if (preferred)
{
impl = try_implementation (preferred, verify_func);
if (impl)
goto done;
}
else
g_warning ("Can't find module '%s' specified in %s", use_this, envvar);
}
else
preferred = NULL;
for (l = g_io_extension_point_get_extensions (ep); l != NULL; l = l->next)
{
extension = l->data;
if (extension == preferred)
continue;
impl = try_implementation (extension, verify_func);
if (impl)
goto done;
}
impl = NULL;
done:
g_hash_table_insert (default_modules,
g_strdup (extension_point),
impl ? g_object_ref (impl) : NULL);
G_UNLOCK (default_modules);
return impl;
}
G_LOCK_DEFINE_STATIC (registered_extensions);
G_LOCK_DEFINE_STATIC (loaded_dirs);

52
gio/gproxyresolver.c
View File

@ -50,52 +50,6 @@ g_proxy_resolver_default_init (GProxyResolverInterface *iface)
{
}
static gpointer
get_default_proxy_resolver (gpointer arg)
{
const gchar *use_this;
GProxyResolver *resolver;
GList *l;
GIOExtensionPoint *ep;
GIOExtension *extension;
use_this = g_getenv ("GIO_USE_PROXY_RESOLVER");
/* Ensure proxy-resolver modules loaded */
_g_io_modules_ensure_loaded ();
ep = g_io_extension_point_lookup (G_PROXY_RESOLVER_EXTENSION_POINT_NAME);
if (use_this)
{
extension = g_io_extension_point_get_extension_by_name (ep, use_this);
if (extension)
{
resolver = g_object_new (g_io_extension_get_type (extension), NULL);
if (g_proxy_resolver_is_supported (resolver))
return resolver;
g_object_unref (resolver);
}
}
for (l = g_io_extension_point_get_extensions (ep); l != NULL; l = l->next)
{
extension = l->data;
resolver = g_object_new (g_io_extension_get_type (extension), NULL);
if (g_proxy_resolver_is_supported (resolver))
return resolver;
g_object_unref (resolver);
}
return NULL;
}
/**
* g_proxy_resolver_get_default:
*
@ -108,9 +62,9 @@ get_default_proxy_resolver (gpointer arg)
GProxyResolver *
g_proxy_resolver_get_default (void)
{
static GOnce once_init = G_ONCE_INIT;
return g_once (&once_init, get_default_proxy_resolver, NULL);
return _g_io_module_get_default (G_PROXY_RESOLVER_EXTENSION_POINT_NAME,
"GIO_USE_PROXY_RESOLVER",
(GIOModuleVerifyFunc)g_proxy_resolver_is_supported);
}
/**

63
gio/gsettingsbackend.c
View File

@ -935,6 +935,22 @@ g_settings_backend_create_tree (void)
g_free, g_settings_backend_variant_unref0);
}
static gboolean
g_settings_backend_verify (gpointer impl)
{
GSettingsBackend *backend = impl;
if (strcmp (G_OBJECT_TYPE_NAME (backend), "GMemorySettingsBackend") == 0 &&
g_strcmp0 (g_getenv ("GSETTINGS_BACKEND"), "memory") != 0)
{
g_message ("Using the 'memory' GSettings backend. Your settings "
"will not be saved or shared with other applications.");
}
g_settings_has_backend = TRUE;
return TRUE;
}
/**
* g_settings_backend_get_default:
* @returns: (transfer full): the default #GSettingsBackend
@ -950,49 +966,12 @@ g_settings_backend_create_tree (void)
GSettingsBackend *
g_settings_backend_get_default (void)
{
static gsize backend;
GSettingsBackend *backend;
if (g_once_init_enter (&backend))
{
GSettingsBackend *instance;
GIOExtensionPoint *point;
GIOExtension *extension;
GType extension_type;
GList *extensions;
const gchar *env;
_g_io_modules_ensure_loaded ();
point = g_io_extension_point_lookup (G_SETTINGS_BACKEND_EXTENSION_POINT_NAME);
extension = NULL;
if ((env = getenv ("GSETTINGS_BACKEND")))
{
extension = g_io_extension_point_get_extension_by_name (point, env);
if (extension == NULL)
g_warning ("Can't find GSettings backend '%s' given in "
"GSETTINGS_BACKEND environment variable", env);
}
if (extension == NULL)
{
extensions = g_io_extension_point_get_extensions (point);
extension = extensions->data;
if (strcmp (g_io_extension_get_name (extension), "memory") == 0)
g_message ("Using the 'memory' GSettings backend. Your settings "
"will not be saved or shared with other applications.");
}
extension_type = g_io_extension_get_type (extension);
instance = g_object_new (extension_type, NULL);
g_settings_has_backend = TRUE;
g_once_init_leave (&backend, (gsize) instance);
}
return g_object_ref ((void *) backend);
backend = _g_io_module_get_default (G_SETTINGS_BACKEND_EXTENSION_POINT_NAME,
"GSETTINGS_BACKEND",
g_settings_backend_verify);
return g_object_ref (backend);
}
/*< private >

35
gio/gtlsbackend.c
View File

@ -80,36 +80,6 @@ g_tls_backend_default_init (GTlsBackendInterface *iface)
{
}
static gpointer
get_default_tls_backend (gpointer arg)
{
const char *use_this;
GList *extensions;
GIOExtensionPoint *ep;
GIOExtension *extension;
_g_io_modules_ensure_loaded ();
ep = g_io_extension_point_lookup (G_TLS_BACKEND_EXTENSION_POINT_NAME);
use_this = g_getenv ("GIO_USE_TLS");
if (use_this)
{
extension = g_io_extension_point_get_extension_by_name (ep, use_this);
if (extension)
return g_object_new (g_io_extension_get_type (extension), NULL);
}
extensions = g_io_extension_point_get_extensions (ep);
if (extensions)
{
extension = extensions->data;
return g_object_new (g_io_extension_get_type (extension), NULL);
}
return NULL;
}
/**
* g_tls_backend_get_default:
*
@ -122,9 +92,8 @@ get_default_tls_backend (gpointer arg)
GTlsBackend *
g_tls_backend_get_default (void)
{
static GOnce once_init = G_ONCE_INIT;
return g_once (&once_init, get_default_tls_backend, NULL);
return _g_io_module_get_default (G_TLS_BACKEND_EXTENSION_POINT_NAME,
"GIO_USE_TLS", NULL);
}
/**

53
gio/gvfs.c
View File

@ -170,53 +170,6 @@ g_vfs_parse_name (GVfs *vfs,
return (* class->parse_name) (vfs, parse_name);
}
static gpointer
get_default_vfs (gpointer arg)
{
const char *use_this;
GVfs *vfs;
GList *l;
GIOExtensionPoint *ep;
GIOExtension *extension;
use_this = g_getenv ("GIO_USE_VFS");
/* Ensure vfs in modules loaded */
_g_io_modules_ensure_loaded ();
ep = g_io_extension_point_lookup (G_VFS_EXTENSION_POINT_NAME);
if (use_this)
{
extension = g_io_extension_point_get_extension_by_name (ep, use_this);
if (extension)
{
vfs = g_object_new (g_io_extension_get_type (extension), NULL);
if (g_vfs_is_active (vfs))
return vfs;
g_object_unref (vfs);
}
}
for (l = g_io_extension_point_get_extensions (ep); l != NULL; l = l->next)
{
extension = l->data;
vfs = g_object_new (g_io_extension_get_type (extension), NULL);
if (g_vfs_is_active (vfs))
return vfs;
g_object_unref (vfs);
}
return NULL;
}
/**
* g_vfs_get_default:
*
@ -227,9 +180,9 @@ get_default_vfs (gpointer arg)
GVfs *
g_vfs_get_default (void)
{
static GOnce once_init = G_ONCE_INIT;
return g_once (&once_init, get_default_vfs, NULL);
return _g_io_module_get_default (G_VFS_EXTENSION_POINT_NAME,
"GIO_USE_VFS",
(GIOModuleVerifyFunc)g_vfs_is_active);
}
/**