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docs: Move the GResource SECTION

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Move it to the struct docs.

Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>

Helps: #3037
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Philip Withnall 2023-10-25 15:05:43 +01:00
parent bbb5479d5a
commit b0b5ed8c34
1 changed files with 107 additions and 86 deletions
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gio/gresource.c
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@ -48,69 +48,72 @@ static void register_lazy_static_resources (void);
G_DEFINE_BOXED_TYPE (GResource, g_resource, g_resource_ref, g_resource_unref) G_DEFINE_BOXED_TYPE (GResource, g_resource, g_resource_ref, g_resource_unref)
/** /**
* SECTION:gresource * GResource:
* @short_description: Resource framework
* @include: gio/gio.h
* *
* Applications and libraries often contain binary or textual data that is * Applications and libraries often contain binary or textual data that is
* really part of the application, rather than user data. For instance * really part of the application, rather than user data. For instance
* #GtkBuilder .ui files, splashscreen images, GMenu markup XML, CSS files, * [class@Gtk.Builder] `.ui` files, splashscreen images, [class@Gio.Menu] markup
* icons, etc. These are often shipped as files in `$datadir/appname`, or * XML, CSS files, icons, etc. These are often shipped as files in
* manually included as literal strings in the code. * `$datadir/appname`, or manually included as literal strings in the code.
* *
* The #GResource API and the [glib-compile-resources][glib-compile-resources] program * The `GResource` API and the
* provide a convenient and efficient alternative to this which has some nice properties. You * [`glib-compile-resources`](glib-compile-resources.html) program provide a
* maintain the files as normal files, so its easy to edit them, but during the build the files * convenient and efficient alternative to this which has some nice properties.
* are combined into a binary bundle that is linked into the executable. This means that loading * You maintain the files as normal files, so it’s easy to edit them, but during
* the resource files are efficient (as they are already in memory, shared with other instances) and * the build the files are combined into a binary bundle that is linked into the
* simple (no need to check for things like I/O errors or locate the files in the filesystem). It * 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. * 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 * Resource files can also be marked as compressed. Such files will be included
* in a compressed form, but will be automatically uncompressed when the resource is used. This * in the resource bundle in a compressed form, but will be automatically
* is very useful e.g. for larger text files that are parsed once (or rarely) and then thrown away. * 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 * 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. * `preprocess` attribute to a comma-separated list of preprocessing options.
* The only options currently supported are: * The only options currently supported are:
* *
* `xml-stripblanks` which will use the xmllint command * - `xml-stripblanks` which will use the [`xmllint`](man:xmllint(1)) command
* to strip ignorable whitespace from the XML file. For this to work, * 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` environment variable must be set to the full path to
* the xmllint executable, or xmllint must be in the `PATH`; otherwise * the xmllint executable, or xmllint must be in the `PATH`; otherwise
* the preprocessing step is skipped. * the preprocessing step is skipped.
* *
* `to-pixdata` (deprecated since gdk-pixbuf 2.32) which will use the * - `to-pixdata` (deprecated since gdk-pixbuf 2.32) which will use the
* `gdk-pixbuf-pixdata` command to convert images to the #GdkPixdata format, * `gdk-pixbuf-pixdata` command to convert images to the [class@Gdk.Pixdata]
* which allows you to create pixbufs directly using the data inside the * format, which allows you to create pixbufs directly using the data inside
* resource file, rather than an (uncompressed) copy of it. For this, the * 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` 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` environment variable must be set to the full path to
* `gdk-pixbuf-pixdata` executable; otherwise the resource compiler will abort. * the `gdk-pixbuf-pixdata` executable; otherwise the resource compiler will
* `to-pixdata` has been deprecated since gdk-pixbuf 2.32, as #GResource * abort. `to-pixdata` has been deprecated since gdk-pixbuf 2.32, as
* supports embedding modern image formats just as well. Instead of using it, * `GResource` supports embedding modern image formats just as well. Instead
* embed a PNG or SVG file in your #GResource. * of using it, embed a PNG or SVG file in your `GResource`.
* *
* `json-stripblanks` which will use the `json-glib-format` command to strip * - `json-stripblanks` which will use the
* ignorable whitespace from the JSON file. For this to work, the * [`json-glib-format`](man:json-glib-format(1)) command to strip ignorable
* `JSON_GLIB_FORMAT` environment variable must be set to the full path to the * whitespace from the JSON file. For this to work, the `JSON_GLIB_FORMAT`
* `json-glib-format` executable, or it must be in the `PATH`; * environment variable must be set to the full path to the
* otherwise the preprocessing step is skipped. In addition, at least version * `json-glib-format` executable, or it must be in the `PATH`; otherwise the
* 1.6 of `json-glib-format` is required. * preprocessing step is skipped. In addition, at least version 1.6 of
* `json-glib-format` is required.
* *
* Resource files will be exported in the GResource namespace using the * Resource files will be exported in the `GResource` namespace using the
* combination of the given `prefix` and the filename from the `file` element. * 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 * 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 * different location in the resource namespace. Typically, this is used to
* include files from a different source directory without exposing the source * include files from a different source directory without exposing the source
* directory in the resource namespace, as in the example below. * directory in the resource namespace, as in the example below.
* *
* Resource bundles are created by the [glib-compile-resources][glib-compile-resources] program * Resource bundles are created by the
* which takes an XML file that describes the bundle, and a set of files that the XML references. These * [`glib-compile-resources`](glib-compile-resources.html) program
* are combined into a binary resource bundle. * 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: * An example resource description:
* |[ * ```xml
* <?xml version="1.0" encoding="UTF-8"?> * <?xml version="1.0" encoding="UTF-8"?>
* <gresources> * <gresources>
* <gresource prefix="/org/gtk/Example"> * <gresource prefix="/org/gtk/Example">
@ -120,74 +123,92 @@ G_DEFINE_BOXED_TYPE (GResource, g_resource, g_resource_ref, g_resource_unref)
* <file alias="example.css">data/example.css</file> * <file alias="example.css">data/example.css</file>
* </gresource> * </gresource>
* </gresources> * </gresources>
* ]| * ```
* *
* This will create a resource bundle with the following files: * This will create a resource bundle with the following files:
* |[ * ```
* /org/gtk/Example/data/splashscreen.png * /org/gtk/Example/data/splashscreen.png
* /org/gtk/Example/dialog.ui * /org/gtk/Example/dialog.ui
* /org/gtk/Example/menumarkup.xml * /org/gtk/Example/menumarkup.xml
* /org/gtk/Example/example.css * /org/gtk/Example/example.css
* ]| * ```
* *
* Note that all resources in the process share the same namespace, so use Java-style * Note that all resources in the process share the same namespace, so use
* path prefixes (like in the above example) to avoid conflicts. * 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 * You can then use [`glib-compile-resources`](glib-compile-resources.html) to
* binary bundle that you can load with g_resource_load(). However, its more common to use the --generate-source and * compile the XML to a binary bundle that you can load with
* --generate-header arguments to create a source file and header to link directly into your application. * [func@Gio.Resource.load]. However, it’s 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 * This will generate `get_resource()`, `register_resource()` and
* `unregister_resource()` functions, prefixed by the `--c-name` argument passed * `unregister_resource()` functions, prefixed by the `--c-name` argument passed
* to [glib-compile-resources][glib-compile-resources]. `get_resource()` returns * to [`glib-compile-resources`](glib-compile-resources.html). `get_resource()`
* the generated #GResource object. The register and unregister functions * returns the generated `GResource` object. The register and unregister
* register the resource so its files can be accessed using * functions register the resource so its files can be accessed using
* g_resources_lookup_data(). * [func@Gio.resources_lookup_data].
* *
* Once a #GResource has been created and registered all the data in it can be accessed globally in the process by * Once a `GResource` has been created and registered all the data in it can be
* using API calls like g_resources_open_stream() to stream the data or g_resources_lookup_data() to get a direct pointer * accessed globally in the process by using API calls like
* to the data. You can also use URIs like "resource:///org/gtk/Example/data/splashscreen.png" with #GFile to access * [func@Gio.resources_open_stream] to stream the data or
* the resource data. * [func@Gio.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
* [iface@Gio.File] to access the resource data.
* *
* Some higher-level APIs, such as #GtkApplication, will automatically load * Some higher-level APIs, such as [class@Gtk.Application], will automatically
* resources from certain well-known paths in the resource namespace as a * load resources from certain well-known paths in the resource namespace as a
* convenience. See the documentation for those APIs for details. * 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 * There are two forms of the generated source, the default version uses the
* and destructor functions (where available) to automatically create and register the #GResource on startup * compiler support for constructor and destructor functions (where available)
* or library load time. If you pass `--manual-register`, two functions to register/unregister the resource are created * to automatically create and register the `GResource` on startup or library
* instead. This requires an explicit initialization call in your application/library, but it works on all platforms, * load time. If you pass `--manual-register`, two functions to
* even on the minor ones where constructors are not supported. (Constructor support is available for at least Win32, Mac OS and Linux.) * 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 * Note that resource data can point directly into the data segment of e.g. a
* during runtime you need to be very careful with keeping around pointers to data from a resource, as this goes away * library, so if you are unloading libraries during runtime you need to be very
* when the library is unloaded. However, in practice this is not generally a problem, since most resource accesses * careful with keeping around pointers to data from a resource, as this goes
* are for your own resources, and resource data is often used once, during parsing, and then released. * 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 * # Overlays
* 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 * When debugging a program or testing a change to an installed version, it is
* resources with replacements from the filesystem. It is a %G_SEARCHPATH_SEPARATOR-separated list of substitutions to perform * often useful to be able to replace resources in the program or library,
* during resource lookups. It is ignored when running in a setuid process. * 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. It is ignored when running in a setuid
* process.
* *
* A substitution has the form * A substitution has the form
* *
* |[ * ```
* /org/gtk/libgtk=/home/desrt/gtk-overlay * /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 * The part before the `=` is the resource subpath for which the overlay
* filesystem path which contains files and subdirectories as you would like to be loaded as resources with the * 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. * equivalent names.
* *
* In the example above, if an application tried to load a resource with the resource path * In the example above, if an application tried to load a resource with the
* `/org/gtk/libgtk/ui/gtkdialog.ui` then GResource would check the filesystem path * resource path `/org/gtk/libgtk/ui/gtkdialog.ui` then `GResource` would check
* `/home/desrt/gtk-overlay/ui/gtkdialog.ui`. If a file was found there, it would be used instead. This is an * the filesystem path `/home/desrt/gtk-overlay/ui/gtkdialog.ui`. If a file was
* overlay, not an outright replacement, which means that if a file is not found at that path, the built-in * found there, it would be used instead. This is an overlay, not an outright
* version will be used instead. Whiteouts are not currently supported. * 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 * Substitutions must start with a slash, and must not contain a trailing slash
* the slash should ideally be absolute, but this is not strictly required. It is possible to overlay the * before the `=`. The path after the slash should ideally be absolute, but
* location of a single resource with an individual file. * this is not strictly required. It is possible to overlay the location of a
* single resource with an individual file.
* *
* Since: 2.32 * Since: 2.32
*/ */