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glib2.0/gio/gresource.c

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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright © 2011 Red Hat, Inc
*
* 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 2.1 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
* 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/>.
*
* Authors: Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
#include <string.h>
#include "gresource.h"
#include <gvdb/gvdb-reader.h>
#include <gi18n-lib.h>
#include <gstdio.h>
#include <gio/gfile.h>
#include <gio/gioerror.h>
#include <gio/gmemoryinputstream.h>
#include <gio/gzlibdecompressor.h>
#include <gio/gconverterinputstream.h>
struct _GResource
{
int ref_count;
GvdbTable *table;
};
static void register_lazy_static_resources (void);
G_DEFINE_BOXED_TYPE (GResource, g_resource, g_resource_ref, g_resource_unref)
/**
* SECTION:gresource
* @short_description: Resource framework
* @include: gio/gio.h
*
* Applications and libraries often contain binary or textual data that is
* really part of the application, rather than user data. For instance
* #GtkBuilder .ui files, splashscreen images, GMenu markup XML, CSS files,
* icons, etc. These are often shipped as files in `$datadir/appname`, or
* manually included as literal strings in the code.
*
* The #GResource API and the [glib-compile-resources][glib-compile-resources] program
* provide a convenient and efficient alternative to this which has some nice properties. You
* maintain the files as normal files, so its easy to edit them, but during the build the files
* are combined into a binary bundle that is linked into the executable. This means that loading
* the resource files are efficient (as they are already in memory, shared with other instances) and
* simple (no need to check for things like I/O errors or locate the files in the filesystem). It
* also makes it easier to create relocatable applications.
*
* Resource files can also be marked as compressed. Such files will be included in the resource bundle
* in a compressed form, but will be automatically uncompressed when the resource is used. This
* is very useful e.g. for larger text files that are parsed once (or rarely) and then thrown away.
*
* Resource files can also be marked to be preprocessed, by setting the value of the
* `preprocess` attribute to a comma-separated list of preprocessing options.
* The only options currently supported are:
*
* `xml-stripblanks` which will use the xmllint command
* to strip ignorable whitespace from the XML file. For this to work,
* the `XMLLINT` environment variable must be set to the full path to
* the xmllint executable, or xmllint must be in the `PATH`; otherwise
* the preprocessing step is skipped.
*
* `to-pixdata` which will use the gdk-pixbuf-pixdata command to convert
* images to the GdkPixdata format, which allows you to create pixbufs directly using the data inside
* the resource file, rather than an (uncompressed) copy of it. For this, the gdk-pixbuf-pixdata
* program must be in the PATH, or the `GDK_PIXBUF_PIXDATA` environment variable must be
* set to the full path to the gdk-pixbuf-pixdata executable; otherwise the resource compiler will
* abort.
*
* Resource files will be exported in the GResource namespace using the
* combination of the given `prefix` and the filename from the `file` element.
* The `alias` attribute can be used to alter the filename to expose them at a
* different location in the resource namespace. Typically, this is used to
* include files from a different source directory without exposing the source
* directory in the resource namespace, as in the example below.
*
* Resource bundles are created by the [glib-compile-resources][glib-compile-resources] program
* which takes an XML file that describes the bundle, and a set of files that the XML references. These
* are combined into a binary resource bundle.
*
* An example resource description:
* |[
* <?xml version="1.0" encoding="UTF-8"?>
* <gresources>
* <gresource prefix="/org/gtk/Example">
* <file>data/splashscreen.png</file>
* <file compressed="true">dialog.ui</file>
* <file preprocess="xml-stripblanks">menumarkup.xml</file>
* <file alias="example.css">data/example.css</file>
* </gresource>
* </gresources>
* ]|
*
* This will create a resource bundle with the following files:
* |[
* /org/gtk/Example/data/splashscreen.png
* /org/gtk/Example/dialog.ui
* /org/gtk/Example/menumarkup.xml
* /org/gtk/Example/example.css
* ]|
*
* Note that all resources in the process share the same namespace, so use Java-style
* path prefixes (like in the above example) to avoid conflicts.
*
* You can then use [glib-compile-resources][glib-compile-resources] to compile the XML to a
* binary bundle that you can load with g_resource_load(). However, its more common to use the --generate-source and
* --generate-header arguments to create a source file and header to link directly into your application.
* This will generate `get_resource()`, `register_resource()` and
* `unregister_resource()` functions, prefixed by the `--c-name` argument passed
* to [glib-compile-resources][glib-compile-resources]. `get_resource()` returns
* the generated #GResource object. The register and unregister functions
* register the resource so its files can be accessed using
* g_resources_lookup_data().
*
* Once a #GResource has been created and registered all the data in it can be accessed globally in the process by
* using API calls like g_resources_open_stream() to stream the data or g_resources_lookup_data() to get a direct pointer
* to the data. You can also use URIs like "resource:///org/gtk/Example/data/splashscreen.png" with #GFile to access
* the resource data.
*
* Some higher-level APIs, such as #GtkApplication, will automatically load
* resources from certain well-known paths in the resource namespace as a
* convenience. See the documentation for those APIs for details.
*
* There are two forms of the generated source, the default version uses the compiler support for constructor
* and destructor functions (where available) to automatically create and register the #GResource on startup
* or library load time. If you pass `--manual-register`, two functions to register/unregister the resource are created
* instead. This requires an explicit initialization call in your application/library, but it works on all platforms,
* even on the minor ones where constructors are not supported. (Constructor support is available for at least Win32, Mac OS and Linux.)
*
* Note that resource data can point directly into the data segment of e.g. a library, so if you are unloading libraries
* during runtime you need to be very careful with keeping around pointers to data from a resource, as this goes away
* when the library is unloaded. However, in practice this is not generally a problem, since most resource accesses
* are for your own resources, and resource data is often used once, during parsing, and then released.
*
* When debugging a program or testing a change to an installed version, it is often useful to be able to
* replace resources in the program or library, without recompiling, for debugging or quick hacking and testing
* purposes. Since GLib 2.50, it is possible to use the `G_RESOURCE_OVERLAYS` environment variable to selectively overlay
* resources with replacements from the filesystem. It is a %G_SEARCHPATH_SEPARATOR-separated list of substitutions to perform
* during resource lookups.
*
* A substitution has the form
*
* |[
* /org/gtk/libgtk=/home/desrt/gtk-overlay
* ]|
*
* The part before the `=` is the resource subpath for which the overlay applies. The part after is a
* filesystem path which contains files and subdirectories as you would like to be loaded as resources with the
* equivalent names.
*
* In the example above, if an application tried to load a resource with the resource path
* `/org/gtk/libgtk/ui/gtkdialog.ui` then GResource would check the filesystem path
* `/home/desrt/gtk-overlay/ui/gtkdialog.ui`. If a file was found there, it would be used instead. This is an
* overlay, not an outright replacement, which means that if a file is not found at that path, the built-in
* version will be used instead. Whiteouts are not currently supported.
*
* Substitutions must start with a slash, and must not contain a trailing slash before the '='. The path after
* the slash should ideally be absolute, but this is not strictly required. It is possible to overlay the
* location of a single resource with an individual file.
*
* Since: 2.32
*/
/**
* GStaticResource:
*
* #GStaticResource is an opaque data structure and can only be accessed
* using the following functions.
**/
typedef gboolean (* CheckCandidate) (const gchar *candidate, gpointer user_data);
static gboolean
open_overlay_stream (const gchar *candidate,
gpointer user_data)
{
GInputStream **res = (GInputStream **) user_data;
GError *error = NULL;
GFile *file;
file = g_file_new_for_path (candidate);
*res = (GInputStream *) g_file_read (file, NULL, &error);
if (*res)
{
g_message ("Opened file '%s' as a resource overlay", candidate);
}
else
{
if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))
g_warning ("Can't open overlay file '%s': %s", candidate, error->message);
g_error_free (error);
}
g_object_unref (file);
return *res != NULL;
}
static gboolean
get_overlay_bytes (const gchar *candidate,
gpointer user_data)
{
GBytes **res = (GBytes **) user_data;
GMappedFile *mapped_file;
GError *error = NULL;
mapped_file = g_mapped_file_new (candidate, FALSE, &error);
if (mapped_file)
{
g_message ("Mapped file '%s' as a resource overlay", candidate);
*res = g_mapped_file_get_bytes (mapped_file);
g_mapped_file_unref (mapped_file);
}
else
{
if (!g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
g_warning ("Can't mmap overlay file '%s': %s", candidate, error->message);
g_error_free (error);
}
return *res != NULL;
}
static gboolean
enumerate_overlay_dir (const gchar *candidate,
gpointer user_data)
{
GHashTable **hash = (GHashTable **) user_data;
GError *error = NULL;
GDir *dir;
const gchar *name;
dir = g_dir_open (candidate, 0, &error);
if (dir)
{
if (*hash == NULL)
/* note: keep in sync with same line below */
*hash = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
g_message ("Enumerating directory '%s' as resource overlay", candidate);
while ((name = g_dir_read_name (dir)))
{
gchar *fullname = g_build_filename (candidate, name, NULL);
/* match gvdb behaviour by suffixing "/" on dirs */
if (g_file_test (fullname, G_FILE_TEST_IS_DIR))
g_hash_table_add (*hash, g_strconcat (name, "/", NULL));
else
g_hash_table_add (*hash, g_strdup (name));
g_free (fullname);
}
g_dir_close (dir);
}
else
{
if (!g_error_matches (error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
g_warning ("Can't enumerate overlay directory '%s': %s", candidate, error->message);
g_error_free (error);
return FALSE;
}
/* We may want to enumerate results from more than one overlay
* directory.
*/
return FALSE;
}
typedef struct {
gsize size;
guint32 flags;
} InfoData;
static gboolean
get_overlay_info (const gchar *candidate,
gpointer user_data)
{
InfoData *info = user_data;
GStatBuf buf;
if (g_stat (candidate, &buf) < 0)
return FALSE;
info->size = buf.st_size;
info->flags = G_RESOURCE_FLAGS_NONE;
return TRUE;
}
static gboolean
g_resource_find_overlay (const gchar *path,
CheckCandidate check,
gpointer user_data)
{
/* This is a null-terminated array of replacement strings (with '=' inside) */
static const gchar * const *overlay_dirs;
gboolean res = FALSE;
gint path_len = -1;
gint i;
/* We try to be very fast in case there are no overlays. Otherwise,
* we can take a bit more time...
*/
if (g_once_init_enter (&overlay_dirs))
{
const gchar * const *result;
const gchar *envvar;
envvar = g_getenv ("G_RESOURCE_OVERLAYS");
if (envvar != NULL)
{
gchar **parts;
gint i, j;
parts = g_strsplit (envvar, G_SEARCHPATH_SEPARATOR_S, 0);
/* Sanity check the parts, dropping those that are invalid.
* 'i' may grow faster than 'j'.
*/
for (i = j = 0; parts[i]; i++)
{
gchar *part = parts[i];
gchar *eq;
eq = strchr (part, '=');
if (eq == NULL)
{
g_critical ("G_RESOURCE_OVERLAYS segment '%s' lacks '='. Ignoring.", part);
g_free (part);
continue;
}
if (eq == part)
{
g_critical ("G_RESOURCE_OVERLAYS segment '%s' lacks path before '='. Ignoring.", part);
g_free (part);
continue;
}
if (eq[1] == '\0')
{
g_critical ("G_RESOURCE_OVERLAYS segment '%s' lacks path after '='. Ignoring", part);
g_free (part);
continue;
}
if (part[0] != '/')
{
g_critical ("G_RESOURCE_OVERLAYS segment '%s' lacks leading '/'. Ignoring.", part);
g_free (part);
continue;
}
if (eq[-1] == '/')
{
g_critical ("G_RESOURCE_OVERLAYS segment '%s' has trailing '/' before '='. Ignoring", part);
g_free (part);
continue;
}
if (!g_path_is_absolute (eq + 1))
{
g_critical ("G_RESOURCE_OVERLAYS segment '%s' does not have an absolute path after '='. Ignoring", part);
g_free (part);
continue;
}
g_message ("Adding GResources overlay '%s'", part);
parts[j++] = part;
}
parts[j] = NULL;
result = (const gchar **) parts;
}
else
{
/* We go out of the way to avoid malloc() in the normal case
* where the environment variable is not set.
*/
static const gchar * const empty_strv[0 + 1];
result = empty_strv;
}
g_once_init_leave (&overlay_dirs, result);
}
for (i = 0; overlay_dirs[i]; i++)
{
const gchar *src;
gint src_len;
const gchar *dst;
gint dst_len;
gchar *candidate;
{
gchar *eq;
/* split the overlay into src/dst */
src = overlay_dirs[i];
eq = strchr (src, '=');
g_assert (eq); /* we checked this already */
src_len = eq - src;
dst = eq + 1;
/* hold off on dst_len because we will probably fail the checks below */
}
if (path_len == -1)
path_len = strlen (path);
/* The entire path is too short to match the source */
if (path_len < src_len)
continue;
/* It doesn't match the source */
if (memcmp (path, src, src_len) != 0)
continue;
/* The prefix matches, but it's not a complete path component */
if (path[src_len] && path[src_len] != '/')
continue;
/* OK. Now we need this. */
dst_len = strlen (dst);
/* The candidate will be composed of:
*
* dst + remaining_path + nul
*/
candidate = g_malloc (dst_len + (path_len - src_len) + 1);
memcpy (candidate, dst, dst_len);
memcpy (candidate + dst_len, path + src_len, path_len - src_len);
candidate[dst_len + (path_len - src_len)] = '\0';
/* No matter what, 'r' is what we need, including the case where
* we are trying to enumerate a directory.
*/
res = (* check) (candidate, user_data);
g_free (candidate);
if (res)
break;
}
return res;
}
/**
* g_resource_error_quark:
*
* Gets the #GResource Error Quark.
*
* Returns: a #GQuark
*
* Since: 2.32
*/
G_DEFINE_QUARK (g-resource-error-quark, g_resource_error)
/**
* g_resource_ref:
* @resource: A #GResource
*
* Atomically increments the reference count of @resource by one. This
* function is MT-safe and may be called from any thread.
*
* Returns: The passed in #GResource
*
* Since: 2.32
**/
GResource *
g_resource_ref (GResource *resource)
{
g_atomic_int_inc (&resource->ref_count);
return resource;
}
/**
* g_resource_unref:
* @resource: A #GResource
*
* Atomically decrements the reference count of @resource by one. If the
* reference count drops to 0, all memory allocated by the resource is
* released. This function is MT-safe and may be called from any
* thread.
*
* Since: 2.32
**/
void
g_resource_unref (GResource *resource)
{
if (g_atomic_int_dec_and_test (&resource->ref_count))
{
gvdb_table_free (resource->table);
g_free (resource);
}
}
/*< internal >
* g_resource_new_from_table:
* @table: (transfer full): a GvdbTable
*
* Returns: (transfer full): a new #GResource for @table
*/
static GResource *
g_resource_new_from_table (GvdbTable *table)
{
GResource *resource;
resource = g_new (GResource, 1);
resource->ref_count = 1;
resource->table = table;
return resource;
}
static void
g_resource_error_from_gvdb_table_error (GError **g_resource_error,
GError *gvdb_table_error /* (transfer full) */)
{
if (g_error_matches (gvdb_table_error, G_FILE_ERROR, G_FILE_ERROR_INVAL))
g_set_error_literal (g_resource_error,
G_RESOURCE_ERROR, G_RESOURCE_ERROR_INTERNAL,
gvdb_table_error->message);
else
g_propagate_error (g_resource_error, g_steal_pointer (&gvdb_table_error));
g_clear_error (&gvdb_table_error);
}
/**
* g_resource_new_from_data:
* @data: A #GBytes
* @error: return location for a #GError, or %NULL
*
* Creates a GResource from a reference to the binary resource bundle.
* This will keep a reference to @data while the resource lives, so
* the data should not be modified or freed.
*
* If you want to use this resource in the global resource namespace you need
* to register it with g_resources_register().
*
* Note: @data must be backed by memory that is at least pointer aligned.
* Otherwise this function will internally create a copy of the memory since
* GLib 2.56, or in older versions fail and exit the process.
*
* If @data is empty or corrupt, %G_RESOURCE_ERROR_INTERNAL will be returned.
*
* Returns: (transfer full): a new #GResource, or %NULL on error
*
* Since: 2.32
**/
GResource *
g_resource_new_from_data (GBytes *data,
GError **error)
{
GvdbTable *table;
gboolean unref_data = FALSE;
GError *local_error = NULL;
if (((guintptr) g_bytes_get_data (data, NULL)) % sizeof (gpointer) != 0)
{
data = g_bytes_new (g_bytes_get_data (data, NULL),
g_bytes_get_size (data));
unref_data = TRUE;
}
table = gvdb_table_new_from_bytes (data, TRUE, &local_error);
if (unref_data)
g_bytes_unref (data);
if (table == NULL)
{
g_resource_error_from_gvdb_table_error (error, g_steal_pointer (&local_error));
return NULL;
}
return g_resource_new_from_table (table);
}
/**
* g_resource_load:
* @filename: (type filename): the path of a filename to load, in the GLib filename encoding
* @error: return location for a #GError, or %NULL
*
* Loads a binary resource bundle and creates a #GResource representation of it, allowing
* you to query it for data.
*
* If you want to use this resource in the global resource namespace you need
* to register it with g_resources_register().
*
* If @filename is empty or the data in it is corrupt,
* %G_RESOURCE_ERROR_INTERNAL will be returned. If @filename doesn’t exist, or
* there is an error in reading it, an error from g_mapped_file_new() will be
* returned.
*
* Returns: (transfer full): a new #GResource, or %NULL on error
*
* Since: 2.32
**/
GResource *
g_resource_load (const gchar *filename,
GError **error)
{
GvdbTable *table;
GError *local_error = NULL;
table = gvdb_table_new (filename, FALSE, &local_error);
if (table == NULL)
{
g_resource_error_from_gvdb_table_error (error, g_steal_pointer (&local_error));
return NULL;
}
return g_resource_new_from_table (table);
}
static gboolean
do_lookup (GResource *resource,
const gchar *path,
GResourceLookupFlags lookup_flags,
gsize *size,
guint32 *flags,
const void **data,
gsize *data_size,
GError **error)
{
char *free_path = NULL;
gsize path_len;
gboolean res = FALSE;
GVariant *value;
/* Drop any trailing slash. */
path_len = strlen (path);
if (path_len >= 1 && path[path_len-1] == '/')
{
path = free_path = g_strdup (path);
free_path[path_len-1] = 0;
}
value = gvdb_table_get_raw_value (resource->table, path);
if (value == NULL)
{
g_set_error (error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND,
_("The resource at “%s” does not exist"),
path);
}
else
{
guint32 _size, _flags;
GVariant *array;
g_variant_get (value, "(uu@ay)",
&_size,
&_flags,
&array);
_size = GUINT32_FROM_LE (_size);
_flags = GUINT32_FROM_LE (_flags);
if (size)
*size = _size;
if (flags)
*flags = _flags;
if (data)
*data = g_variant_get_data (array);
if (data_size)
{
/* Don't report trailing newline that non-compressed files has */
if (_flags & G_RESOURCE_FLAGS_COMPRESSED)
*data_size = g_variant_get_size (array);
else
*data_size = g_variant_get_size (array) - 1;
}
g_variant_unref (array);
g_variant_unref (value);
res = TRUE;
}
g_free (free_path);
return res;
}
/**
* g_resource_open_stream:
* @resource: A #GResource
* @path: A pathname inside the resource
* @lookup_flags: A #GResourceLookupFlags
* @error: return location for a #GError, or %NULL
*
* Looks for a file at the specified @path in the resource and
* returns a #GInputStream that lets you read the data.
*
* @lookup_flags controls the behaviour of the lookup.
*
* Returns: (transfer full): #GInputStream or %NULL on error.
* Free the returned object with g_object_unref()
*
* Since: 2.32
**/
GInputStream *
g_resource_open_stream (GResource *resource,
const gchar *path,
GResourceLookupFlags lookup_flags,
GError **error)
{
const void *data;
gsize data_size;
guint32 flags;
GInputStream *stream, *stream2;
if (!do_lookup (resource, path, lookup_flags, NULL, &flags, &data, &data_size, error))
return NULL;
stream = g_memory_input_stream_new_from_data (data, data_size, NULL);
g_object_set_data_full (G_OBJECT (stream), "g-resource",
g_resource_ref (resource),
(GDestroyNotify)g_resource_unref);
if (flags & G_RESOURCE_FLAGS_COMPRESSED)
{
GZlibDecompressor *decompressor =
g_zlib_decompressor_new (G_ZLIB_COMPRESSOR_FORMAT_ZLIB);
stream2 = g_converter_input_stream_new (stream, G_CONVERTER (decompressor));
g_object_unref (decompressor);
g_object_unref (stream);
stream = stream2;
}
return stream;
}
/**
* g_resource_lookup_data:
* @resource: A #GResource
* @path: A pathname inside the resource
* @lookup_flags: A #GResourceLookupFlags
* @error: return location for a #GError, or %NULL
*
* Looks for a file at the specified @path in the resource and
* returns a #GBytes that lets you directly access the data in
* memory.
*
* The data is always followed by a zero byte, so you
* can safely use the data as a C string. However, that byte
* is not included in the size of the GBytes.
*
* For uncompressed resource files this is a pointer directly into
* the resource bundle, which is typically in some readonly data section
* in the program binary. For compressed files we allocate memory on
* the heap and automatically uncompress the data.
*
* @lookup_flags controls the behaviour of the lookup.
*
* Returns: (transfer full): #GBytes or %NULL on error.
* Free the returned object with g_bytes_unref()
*
* Since: 2.32
**/
GBytes *
g_resource_lookup_data (GResource *resource,
const gchar *path,
GResourceLookupFlags lookup_flags,
GError **error)
{
const void *data;
guint32 flags;
gsize data_size;
gsize size;
if (!do_lookup (resource, path, lookup_flags, &size, &flags, &data, &data_size, error))
return NULL;
if (flags & G_RESOURCE_FLAGS_COMPRESSED)
{
char *uncompressed, *d;
const char *s;
GConverterResult res;
gsize d_size, s_size;
gsize bytes_read, bytes_written;
GZlibDecompressor *decompressor =
g_zlib_decompressor_new (G_ZLIB_COMPRESSOR_FORMAT_ZLIB);
uncompressed = g_malloc (size + 1);
s = data;
s_size = data_size;
d = uncompressed;
d_size = size;
do
{
res = g_converter_convert (G_CONVERTER (decompressor),
s, s_size,
d, d_size,
G_CONVERTER_INPUT_AT_END,
&bytes_read,
&bytes_written,
NULL);
if (res == G_CONVERTER_ERROR)
{
g_free (uncompressed);
g_object_unref (decompressor);
g_set_error (error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_INTERNAL,
_("The resource at “%s” failed to decompress"),
path);
return NULL;
}
s += bytes_read;
s_size -= bytes_read;
d += bytes_written;
d_size -= bytes_written;
}
while (res != G_CONVERTER_FINISHED);
uncompressed[size] = 0; /* Zero terminate */
g_object_unref (decompressor);
return g_bytes_new_take (uncompressed, size);
}
else
return g_bytes_new_with_free_func (data, data_size, (GDestroyNotify)g_resource_unref, g_resource_ref (resource));
}
/**
* g_resource_get_info:
* @resource: A #GResource
* @path: A pathname inside the resource
* @lookup_flags: A #GResourceLookupFlags
* @size: (out) (optional): a location to place the length of the contents of the file,
* or %NULL if the length is not needed
* @flags: (out) (optional): a location to place the flags about the file,
* or %NULL if the length is not needed
* @error: return location for a #GError, or %NULL
*
* Looks for a file at the specified @path in the resource and
* if found returns information about it.
*
* @lookup_flags controls the behaviour of the lookup.
*
* Returns: %TRUE if the file was found. %FALSE if there were errors
*
* Since: 2.32
**/
gboolean
g_resource_get_info (GResource *resource,
const gchar *path,
GResourceLookupFlags lookup_flags,
gsize *size,
guint32 *flags,
GError **error)
{
return do_lookup (resource, path, lookup_flags, size, flags, NULL, NULL, error);
}
/**
* g_resource_enumerate_children:
* @resource: A #GResource
* @path: A pathname inside the resource
* @lookup_flags: A #GResourceLookupFlags
* @error: return location for a #GError, or %NULL
*
* Returns all the names of children at the specified @path in the resource.
* The return result is a %NULL terminated list of strings which should
* be released with g_strfreev().
*
* If @path is invalid or does not exist in the #GResource,
* %G_RESOURCE_ERROR_NOT_FOUND will be returned.
*
* @lookup_flags controls the behaviour of the lookup.
*
* Returns: (array zero-terminated=1) (transfer full): an array of constant strings
*
* Since: 2.32
**/
gchar **
g_resource_enumerate_children (GResource *resource,
const gchar *path,
GResourceLookupFlags lookup_flags,
GError **error)
{
gchar local_str[256];
const gchar *path_with_slash;
gchar **children;
gchar *free_path = NULL;
gsize path_len;
/*
* Size of 256 is arbitrarily chosen based on being large enough
* for pretty much everything we come across, but not cumbersome
* on the stack. It also matches common cacheline sizes.
*/
if (*path == 0)
{
g_set_error (error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND,
_("The resource at “%s” does not exist"),
path);
return NULL;
}
path_len = strlen (path);
if G_UNLIKELY (path[path_len-1] != '/')
{
if (path_len < sizeof (local_str) - 2)
{
/*
* We got a path that does not have a trailing /. It is not the
* ideal use of this API as we require trailing / for our lookup
* into gvdb. Some degenerate application configurations can hit
* this code path quite a bit, so we try to avoid using the
* g_strconcat()/g_free().
*/
memcpy (local_str, path, path_len);
local_str[path_len] = '/';
local_str[path_len+1] = 0;
path_with_slash = local_str;
}
else
{
path_with_slash = free_path = g_strconcat (path, "/", NULL);
}
}
else
{
path_with_slash = path;
}
children = gvdb_table_list (resource->table, path_with_slash);
g_free (free_path);
if (children == NULL)
{
g_set_error (error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND,
_("The resource at “%s” does not exist"),
path);
return NULL;
}
return children;
}
static GRWLock resources_lock;
static GList *registered_resources;
/* This is updated atomically, so we can append to it and check for NULL outside the
lock, but all other accesses are done under the write lock */
static GStaticResource *lazy_register_resources;
static void
g_resources_register_unlocked (GResource *resource)
{
registered_resources = g_list_prepend (registered_resources, g_resource_ref (resource));
}
static void
g_resources_unregister_unlocked (GResource *resource)
{
if (g_list_find (registered_resources, resource) == NULL)
{
g_warning ("Tried to remove not registered resource");
}
else
{
registered_resources = g_list_remove (registered_resources, resource);
g_resource_unref (resource);
}
}
/**
* g_resources_register:
* @resource: A #GResource
*
* Registers the resource with the process-global set of resources.
* Once a resource is registered the files in it can be accessed
* with the global resource lookup functions like g_resources_lookup_data().
*
* Since: 2.32
**/
void
g_resources_register (GResource *resource)
{
g_rw_lock_writer_lock (&resources_lock);
g_resources_register_unlocked (resource);
g_rw_lock_writer_unlock (&resources_lock);
}
/**
* g_resources_unregister:
* @resource: A #GResource
*
* Unregisters the resource from the process-global set of resources.
*
* Since: 2.32
**/
void
g_resources_unregister (GResource *resource)
{
g_rw_lock_writer_lock (&resources_lock);
g_resources_unregister_unlocked (resource);
g_rw_lock_writer_unlock (&resources_lock);
}
/**
* g_resources_open_stream:
* @path: A pathname inside the resource
* @lookup_flags: A #GResourceLookupFlags
* @error: return location for a #GError, or %NULL
*
* Looks for a file at the specified @path in the set of
* globally registered resources and returns a #GInputStream
* that lets you read the data.
*
* @lookup_flags controls the behaviour of the lookup.
*
* Returns: (transfer full): #GInputStream or %NULL on error.
* Free the returned object with g_object_unref()
*
* Since: 2.32
**/
GInputStream *
g_resources_open_stream (const gchar *path,
GResourceLookupFlags lookup_flags,
GError **error)
{
GInputStream *res = NULL;
GList *l;
GInputStream *stream;
if (g_resource_find_overlay (path, open_overlay_stream, &res))
return res;
register_lazy_static_resources ();
g_rw_lock_reader_lock (&resources_lock);
for (l = registered_resources; l != NULL; l = l->next)
{
GResource *r = l->data;
GError *my_error = NULL;
stream = g_resource_open_stream (r, path, lookup_flags, &my_error);
if (stream == NULL &&
g_error_matches (my_error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND))
{
g_clear_error (&my_error);
}
else
{
if (stream == NULL)
g_propagate_error (error, my_error);
res = stream;
break;
}
}
if (l == NULL)
g_set_error (error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND,
_("The resource at “%s” does not exist"),
path);
g_rw_lock_reader_unlock (&resources_lock);
return res;
}
/**
* g_resources_lookup_data:
* @path: A pathname inside the resource
* @lookup_flags: A #GResourceLookupFlags
* @error: return location for a #GError, or %NULL
*
* Looks for a file at the specified @path in the set of
* globally registered resources and returns a #GBytes that
* lets you directly access the data in memory.
*
* The data is always followed by a zero byte, so you
* can safely use the data as a C string. However, that byte
* is not included in the size of the GBytes.
*
* For uncompressed resource files this is a pointer directly into
* the resource bundle, which is typically in some readonly data section
* in the program binary. For compressed files we allocate memory on
* the heap and automatically uncompress the data.
*
* @lookup_flags controls the behaviour of the lookup.
*
* Returns: (transfer full): #GBytes or %NULL on error.
* Free the returned object with g_bytes_unref()
*
* Since: 2.32
**/
GBytes *
g_resources_lookup_data (const gchar *path,
GResourceLookupFlags lookup_flags,
GError **error)
{
GBytes *res = NULL;
GList *l;
GBytes *data;
if (g_resource_find_overlay (path, get_overlay_bytes, &res))
return res;
register_lazy_static_resources ();
g_rw_lock_reader_lock (&resources_lock);
for (l = registered_resources; l != NULL; l = l->next)
{
GResource *r = l->data;
GError *my_error = NULL;
data = g_resource_lookup_data (r, path, lookup_flags, &my_error);
if (data == NULL &&
g_error_matches (my_error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND))
{
g_clear_error (&my_error);
}
else
{
if (data == NULL)
g_propagate_error (error, my_error);
res = data;
break;
}
}
if (l == NULL)
g_set_error (error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND,
_("The resource at “%s” does not exist"),
path);
g_rw_lock_reader_unlock (&resources_lock);
return res;
}
/**
* g_resources_enumerate_children:
* @path: A pathname inside the resource
* @lookup_flags: A #GResourceLookupFlags
* @error: return location for a #GError, or %NULL
*
* Returns all the names of children at the specified @path in the set of
* globally registered resources.
* The return result is a %NULL terminated list of strings which should
* be released with g_strfreev().
*
* @lookup_flags controls the behaviour of the lookup.
*
* Returns: (array zero-terminated=1) (transfer full): an array of constant strings
*
* Since: 2.32
**/
gchar **
g_resources_enumerate_children (const gchar *path,
GResourceLookupFlags lookup_flags,
GError **error)
{
GHashTable *hash = NULL;
GList *l;
char **children;
int i;
/* This will enumerate actual files found in overlay directories but
* will not enumerate the overlays themselves. For example, if we
* have an overlay "/org/gtk=/path/to/files" and we enumerate "/org"
* then we will not see "gtk" in the result set unless it is provided
* by another resource file.
*
* This is probably not going to be a problem since if we are doing
* such an overlay, we probably will already have that path.
*/
g_resource_find_overlay (path, enumerate_overlay_dir, &hash);
register_lazy_static_resources ();
g_rw_lock_reader_lock (&resources_lock);
for (l = registered_resources; l != NULL; l = l->next)
{
GResource *r = l->data;
children = g_resource_enumerate_children (r, path, 0, NULL);
if (children != NULL)
{
if (hash == NULL)
/* note: keep in sync with same line above */
hash = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
for (i = 0; children[i] != NULL; i++)
g_hash_table_add (hash, children[i]);
g_free (children);
}
}
g_rw_lock_reader_unlock (&resources_lock);
if (hash == NULL)
{
g_set_error (error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND,
_("The resource at “%s” does not exist"),
path);
return NULL;
}
else
{
children = (gchar **) g_hash_table_get_keys_as_array (hash, NULL);
g_hash_table_steal_all (hash);
g_hash_table_destroy (hash);
return children;
}
}
/**
* g_resources_get_info:
* @path: A pathname inside the resource
* @lookup_flags: A #GResourceLookupFlags
* @size: (out) (optional): a location to place the length of the contents of the file,
* or %NULL if the length is not needed
* @flags: (out) (optional): a location to place the #GResourceFlags about the file,
* or %NULL if the flags are not needed
* @error: return location for a #GError, or %NULL
*
* Looks for a file at the specified @path in the set of
* globally registered resources and if found returns information about it.
*
* @lookup_flags controls the behaviour of the lookup.
*
* Returns: %TRUE if the file was found. %FALSE if there were errors
*
* Since: 2.32
**/
gboolean
g_resources_get_info (const gchar *path,
GResourceLookupFlags lookup_flags,
gsize *size,
guint32 *flags,
GError **error)
{
gboolean res = FALSE;
GList *l;
gboolean r_res;
InfoData info;
if (g_resource_find_overlay (path, get_overlay_info, &info))
{
if (size)
*size = info.size;
if (flags)
*flags = info.flags;
return TRUE;
}
register_lazy_static_resources ();
g_rw_lock_reader_lock (&resources_lock);
for (l = registered_resources; l != NULL; l = l->next)
{
GResource *r = l->data;
GError *my_error = NULL;
r_res = g_resource_get_info (r, path, lookup_flags, size, flags, &my_error);
if (!r_res &&
g_error_matches (my_error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND))
{
g_clear_error (&my_error);
}
else
{
if (!r_res)
g_propagate_error (error, my_error);
res = r_res;
break;
}
}
if (l == NULL)
g_set_error (error, G_RESOURCE_ERROR, G_RESOURCE_ERROR_NOT_FOUND,
_("The resource at “%s” does not exist"),
path);
g_rw_lock_reader_unlock (&resources_lock);
return res;
}
/* This code is to handle registration of resources very early, from a constructor.
* At that point we'd like to do minimal work, to avoid ordering issues. For instance,
* we're not allowed to use g_malloc, as the user need to be able to call g_mem_set_vtable
* before the first call to g_malloc.
*
* So, what we do at construction time is that we just register a static structure on
* a list of resources that need to be initialized, and then later, when doing any lookups
* in the global list of registered resources, or when getting a reference to the
* lazily initialized resource we lazily create and register all the GResources on
* the lazy list.
*
* To avoid having to use locks in the constructor, and having to grab the writer lock
* when checking the lazy registering list we update lazy_register_resources in
* a lock-less fashion (atomic prepend-only, atomic replace with NULL). However, all
* operations except:
* * check if there are any resources to lazily initialize
* * Add a static resource to the lazy init list
* Do use the full writer lock for protection.
*/
static void
register_lazy_static_resources_unlocked (void)
{
GStaticResource *list;
do
list = lazy_register_resources;
while (!g_atomic_pointer_compare_and_exchange (&lazy_register_resources, list, NULL));
while (list != NULL)
{
GBytes *bytes = g_bytes_new_static (list->data, list->data_len);
GResource *resource = g_resource_new_from_data (bytes, NULL);
if (resource)
{
g_resources_register_unlocked (resource);
g_atomic_pointer_set (&list->resource, resource);
}
g_bytes_unref (bytes);
list = list->next;
}
}
static void
register_lazy_static_resources (void)
{
if (g_atomic_pointer_get (&lazy_register_resources) == NULL)
return;
g_rw_lock_writer_lock (&resources_lock);
register_lazy_static_resources_unlocked ();
g_rw_lock_writer_unlock (&resources_lock);
}
/**
* g_static_resource_init:
* @static_resource: pointer to a static #GStaticResource
*
* Initializes a GResource from static data using a
* GStaticResource.
*
* This is normally used by code generated by
* [glib-compile-resources][glib-compile-resources]
* and is not typically used by other code.
*
* Since: 2.32
**/
void
g_static_resource_init (GStaticResource *static_resource)
{
gpointer next;
do
{
next = lazy_register_resources;
static_resource->next = next;
}
while (!g_atomic_pointer_compare_and_exchange (&lazy_register_resources, next, static_resource));
}
/**
* g_static_resource_fini:
* @static_resource: pointer to a static #GStaticResource
*
* Finalized a GResource initialized by g_static_resource_init().
*
* This is normally used by code generated by
* [glib-compile-resources][glib-compile-resources]
* and is not typically used by other code.
*
* Since: 2.32
**/
void
g_static_resource_fini (GStaticResource *static_resource)
{
GResource *resource;
g_rw_lock_writer_lock (&resources_lock);
register_lazy_static_resources_unlocked ();
resource = g_atomic_pointer_get (&static_resource->resource);
if (resource)
{
g_atomic_pointer_set (&static_resource->resource, NULL);
g_resources_unregister_unlocked (resource);
g_resource_unref (resource);
}
g_rw_lock_writer_unlock (&resources_lock);
}
/**
* g_static_resource_get_resource:
* @static_resource: pointer to a static #GStaticResource
*
* Gets the GResource that was registered by a call to g_static_resource_init().
*
* This is normally used by code generated by
* [glib-compile-resources][glib-compile-resources]
* and is not typically used by other code.
*
* Returns: (transfer none): a #GResource
*
* Since: 2.32
**/
GResource *
g_static_resource_get_resource (GStaticResource *static_resource)
{
register_lazy_static_resources ();
return g_atomic_pointer_get (&static_resource->resource);
}
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