Struct Resource 

pub struct Resource { /* private fields */ }

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 unregister_resource() functions, prefixed by the --c-name argument passed to 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 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 resources_open_stream() to stream the data or 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 File 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.

Overlays

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. It is ignored when running in a setuid process.

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 filesystem path after the = 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.

GLib type: Shared boxed type with reference counted clone semantics.

Implementations

impl Resource

pub fn from_data(data: &Bytes) -> Result<Resource, Error>

Creates a Resource 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 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, ResourceError::Internal will be returned.

data

A glib::Bytes

Returns

a new Resource, or NULL on error

impl Resource

pub fn as_ptr(&self) -> *mut GResource

Return the inner pointer to the underlying C value.

pub unsafe fn from_glib_ptr_borrow(ptr: &*mut GResource) -> &Self

Borrows the underlying C value.

impl Resource

pub fn enumerate_children( &self, path: &str, lookup_flags: ResourceLookupFlags, ) -> Result<Vec<GString>, Error>

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 strfreev().

If @path is invalid or does not exist in the Resource, ResourceError::NotFound will be returned.

@lookup_flags controls the behaviour of the lookup.

path

A path name inside the resource

lookup_flags

A ResourceLookupFlags

Returns

an array of constant strings

pub fn info( &self, path: &str, lookup_flags: ResourceLookupFlags, ) -> Result<(usize, u32), Error>

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.

The only error this can return is ResourceError::NotFound, if @path was not found in @self.

path

A path name inside the resource

lookup_flags

A ResourceLookupFlags

Returns

TRUE if the file was found, FALSE if there were errors

size

a location to place the length of the contents of the file, or NULL if the length is not needed

flags

a location to place the flags about the file, or NULL if the length is not needed

pub fn has_children(&self, path: &str) -> bool

Available on crate feature v2_84 only.

Returns whether the specified @path in the resource has children.

path

A pathname inside the resource

Returns

true if @path has children

pub fn lookup_data( &self, path: &str, lookup_flags: ResourceLookupFlags, ) -> Result<Bytes, Error>

Looks for a file at the specified @path in the resource and returns a glib::Bytes 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 glib::Bytes.

For uncompressed resource files this is a pointer directly into the resource bundle, which is typically in some read-only data section in the program binary. For compressed files, memory is allocated on the heap and the data is automatically uncompressed.

@lookup_flags controls the behaviour of the lookup.

This can return error ResourceError::NotFound if @path was not found in @self, or ResourceError::Internal if decompression of a compressed resource failed.

path

A path name inside the resource

lookup_flags

A ResourceLookupFlags

Returns

glib::Bytes or NULL on error

pub fn open_stream( &self, path: &str, lookup_flags: ResourceLookupFlags, ) -> Result<InputStream, Error>

Looks for a file at the specified @path in the resource and returns a InputStream that lets you read the data.

@lookup_flags controls the behaviour of the lookup.

The only error this can return is ResourceError::NotFound, if @path was not found in @self.

path

A path name inside the resource

lookup_flags

A ResourceLookupFlags

Returns

InputStream or NULL on error

pub fn load(filename: impl AsRef<Path>) -> Result<Resource, Error>

t exist, or there is an error in reading it, an error from GLib::MappedFile::new() will be returned.

filename

the path of a filename to load, in the GLib filename encoding

Returns

a new Resource, or NULL on error

Trait Implementations

impl Clone for Resource

fn clone(&self) -> Self

Makes a clone of this shared reference.

This increments the strong reference count of the reference. Dropping the reference will decrement it again.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Resource

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Resource

impl From<Resource> for Value

fn from(s: Resource) -> Self

Converts to this type from the input type.

impl HasParamSpec for Resource

type ParamSpec = ParamSpecBoxed

type SetValue = Resource

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(&str) -> ParamSpecBoxedBuilder<'_, Resource>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for Resource

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Resource

fn cmp(&self, other: &Resource) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Resource

fn eq(&self, other: &Resource) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Resource

fn partial_cmp(&self, other: &Resource) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for Resource

fn static_type() -> Type

Returns the type identifier of Self.

impl StructuralPartialEq for Resource