glib/

wrapper.rs

// Take a look at the license at the top of the repository in the LICENSE file.

// rustdoc-stripper-ignore-next
//! `IMPL` The `wrapper!` macro and miscellaneous wrapper traits.

// rustdoc-stripper-ignore-next
/// Defines a wrapper type and implements the appropriate traits.
///
/// The basic syntax is
///
/// ```ignore
/// wrapper! {
///     /// Your documentation goes here
///     pub struct $name($kind<$foreign>);
///
///     match fn {
///         $fn_name => /* a closure-like expression */,
///         ...
///     }
/// }
/// ```
///
/// This creates a wrapper named `$name` around the foreign type
/// `$foreign` of `$kind` — one of [`Boxed`][#boxed],
/// [`Shared`][#shared], or [`Object`][#object].
///
/// Inside the `match fn` block there are closure-like expressions to
/// provide ways of copying/freeing, or referencing/unreferencing the
/// value that you are wrapping.  These expressions will be evaluated
/// in an `unsafe` context, since they frequently invoke `extern`
/// functions from an FFI crate.
///
/// What follows is a description of each of the possible `$kind`:
/// [`Boxed`][#boxed], [`BoxedInline`][#boxedinline], [`Shared`][#shared],
/// [`Object`][#object], and [`ObjectSubclass`][#objectsubclass];
/// note that each supports different sets of `$fn_name` inside the
/// `match fn` block.  Also, `Object` may require you to specify
/// things like the class struct to wrap, plus any interfaces that the
/// class implements.
///
/// ### Boxed (heap allocated)
///
/// Boxed records with single ownership allocated on the heap.
///
/// With no registered `glib_ffi::GType`:
///
/// ```ignore
/// wrapper! {
///     /// Text buffer iterator
///     pub struct TextIter(Boxed<ffi::GtkTextIter>);
///
///     match fn {
///         copy => |ptr| ffi::gtk_text_iter_copy(ptr),
///         free => |ptr| ffi::gtk_text_iter_free(ptr),
///     }
/// }
/// ```
///
/// `copy`: `|*const $foreign| -> *mut $foreign` creates a copy of the value.
///
/// `free`: `|*mut $foreign|` frees the value.
///
/// With a registered `glib_ffi::GType`:
///
/// ```ignore
/// wrapper! {
///     /// Text buffer iterator
///     pub struct TextIter(Boxed<ffi::GtkTextIter>);
///
///     match fn {
///         copy     => |ptr| ffi::gtk_text_iter_copy(ptr),
///         free     => |ptr| ffi::gtk_text_iter_free(ptr),
///         type_ => ||    ffi::gtk_text_iter_get_type(),
///     }
/// }
/// ```
///
/// `type_`: `|| -> glib_ffi::GType` (optional) returns the
/// `glib_ffi::GType` that corresponds to the foreign struct.
///
/// ### BoxedInline (inline, stack allocated)
///
/// Boxed records with single ownership allocated on the stack or otherwise inline.
/// With no registered `glib_ffi::GType`:
///
/// ```ignore
/// wrapper! {
///     /// Text buffer iterator
///     pub struct TextIter(BoxedInline<ffi::GtkTextIter>);
///
///     match fn {
///         copy => |ptr| ffi::gtk_text_iter_copy(ptr),
///         free => |ptr| ffi::gtk_text_iter_free(ptr),
///     }
/// }
/// ```
///
/// `copy`: `|*const $foreign| -> *mut $foreign` (optional) creates a heap allocated copy of the value.
///
/// `free`: `|*mut $foreign|` (optional) frees the value.
///
/// With a registered `glib_ffi::GType`:
///
/// ```ignore
/// wrapper! {
///     /// Text buffer iterator
///     pub struct TextIter(BoxedInline<ffi::GtkTextIter>);
///
///     match fn {
///         copy     => |ptr| ffi::gtk_text_iter_copy(ptr),
///         free     => |ptr| ffi::gtk_text_iter_free(ptr),
///         type_ => ||    ffi::gtk_text_iter_get_type(),
///     }
/// }
/// ```
///
/// `type_`: `|| -> glib_ffi::GType` (optional) returns the
/// `glib_ffi::GType` that corresponds to the foreign struct.
///
/// ### Shared
///
/// Records with reference-counted, shared ownership.
///
/// With no registered `glib_ffi::GType`:
///
/// ```ignore
/// wrapper! {
///     /// Object holding timing information for a single frame.
///     pub struct FrameTimings(Shared<ffi::GdkFrameTimings>);
///
///     match fn {
///         ref   => |ptr| ffi::gdk_frame_timings_ref(ptr),
///         unref => |ptr| ffi::gdk_frame_timings_unref(ptr),
///     }
/// }
/// ```
///
/// `ref`: `|*mut $foreign|` increases the refcount.
///
/// `unref`: `|*mut $foreign|` decreases the refcount.
///
/// With a registered `glib_ffi::GType`:
///
/// ```ignore
/// wrapper! {
///     /// Object holding timing information for a single frame.
///     pub struct FrameTimings(Shared<ffi::GdkFrameTimings>);
///
///     match fn {
///         ref      => |ptr| ffi::gdk_frame_timings_ref(ptr),
///         unref    => |ptr| ffi::gdk_frame_timings_unref(ptr),
///         type_ => ||    ffi::gdk_frame_timings_get_type(),
///     }
/// }
/// ```
///
/// `type_`: `|| -> glib_ffi::GType` (optional) returns the
/// `glib_ffi::GType` that corresponds to the foreign struct.
///
/// ### Object
///
/// Objects -- classes.  Note that the class name, if available, must be specified after the
/// $foreign type; see below for [non-derivable classes][#non-derivable-classes].
///
/// The basic syntax is this:
///
/// ```ignore
/// wrapper! {
///     /// Your documentation goes here
///     pub struct InstanceName(Object<ffi::InstanceStruct, ffi::ClassStruct>)
///         @extends ParentClass, GrandparentClass, ...,
///         @implements Interface1, Interface2, ...;
///
///     match fn {
///         type_ => || ffi::instance_get_type(),
///     }
/// }
/// ```
///
/// `type_`: `|| -> glib_ffi::GType` returns the `glib_ffi::GType`
/// that corresponds to the foreign class.
///
/// #### All parent classes must be specified
///
/// In the example above, "`@extends ParentClass, GrandparentClass, ...,`" is where you must
/// specify all the parent classes of the one you are wrapping. The uppermost parent class,
/// `glib::Object`, must not be specified.
///
/// For example, `ffi::GtkWindowGroup` derives directly from
/// `GObject`, so it can be simply wrapped as follows:
///
/// ```ignore
/// wrapper! {
///     pub struct WindowGroup(Object<ffi::GtkWindowGroup, ffi::GtkWindowGroupClass>);
///
///     match fn {
///         type_ => || ffi::gtk_window_group_get_type(),
///     }
/// }
/// ```
///
/// In contrast, `ffi::GtkButton` has a parent, grandparent, etc. classes, which must be specified:
///
/// ```ignore
/// wrapper! {
///     pub struct Button(Object<ffi::GtkButton>) @extends Bin, Container, Widget;
///         // see note on interfaces in the example below
///
///     match fn {
///         type_ => || ffi::gtk_button_get_type(),
///     }
/// }
/// ```
///
/// #### Objects which implement interfaces
///
/// The example above is incomplete, since `ffi::GtkButton` actually implements two interfaces,
/// `Buildable` and `Actionable`.  In this case, they must be specified after all the parent classes
/// behind the `@implements` keyword:
///
/// ```ignore
/// wrapper! {
///     pub struct Button(Object<ffi::GtkButton>)
///         @extends Bin, Container, Widget, // parent classes
///         @implements Buildable, Actionable;  // interfaces
///
///     match fn {
///         type_ => || ffi::gtk_button_get_type(),
///     }
/// }
/// ```
///
/// #### Non-derivable classes
///
/// By convention, GObject implements "final" classes, i.e. those who
/// cannot be subclassed, by *not* exposing a public Class struct.
/// This way it is not possible to override any methods, as there are
/// no `klass.method_name` fields to overwrite.  In this case, don't
/// specify a FFI class name at all in the `Object<>` part:
///
/// ```ignore
/// wrapper! {
///     pub struct Clipboard(Object<ffi::GtkClipboard>);
///     ...
/// }
/// ```
///
/// #### Interfaces
///
/// Interfaces are passed in the same way to the macro but instead of specifying
/// `Object`, `Interface` has to be specified:
///
/// ```ignore
/// wrapper! {
///     pub struct TreeModel(Interface<ffi::GtkTreeModel, ffi::GtkTreeModelIface>);
///     ...
/// }
/// ```
///
/// #### Interfaces with prerequisites
///
/// Interfaces can declare prerequisites, i.e. the classes from which types that implement the
/// interface have to inherit or interfaces that have to be implemented:
///
/// ```ignore
/// wrapper! {
///     pub struct TreeSortable(Interface<ffi::GtkTreeSortable, ffi::GtkTreeSortable>) @requires TreeModel;
///     ...
/// }
/// ```
///
/// ### ObjectSubclass
///
/// Wrappers for objects whose implementation is a Rust
/// [`ObjectSubclass`](crate::subclass::types::ObjectSubclass). This is used to define the outer
/// type of a subclass implementation, typically together with `#[derive(ObjectSubclass)]`.
///
/// The basic syntax is:
///
/// ```ignore
/// wrapper! {
///     pub struct MyObject(ObjectSubclass<imp::MyObject>)
///         @extends ParentClass, GrandparentClass, ...,
///         @implements Interface1, Interface2, ...;
/// }
/// ```
///
/// Unlike the other kinds no `match fn` block is needed: the GType and the parent type are taken
/// from the [`ObjectSubclass`](crate::subclass::types::ObjectSubclass) implementation.
/// `@extends` and `@implements` are optional and list the parent classes and interfaces of the
/// wrapper.
///
/// [#boxed]: #boxed
/// [#boxedinline]: #boxedinline
/// [#shared]: #shared
/// [#object]: #object
/// [#objectsubclass]: #objectsubclass
/// [#non-derivable-classes]: #non-derivable-classes
#[macro_export]
macro_rules! wrapper {
    // Boxed
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (Boxed<$ffi_name:ty>);

        match fn {
            copy => |$copy_arg:ident| $copy_expr:expr,
            free => |$free_arg:ident| $free_expr:expr,
            $(
            type_ => || $get_type_expr:expr,
            )?
        }
    ) => {
        $crate::glib_boxed_wrapper!(
            [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, $ffi_name,
            @copy $copy_arg $copy_expr, @free $free_arg $free_expr
            $(, @type_ $get_type_expr)?
        );
    };

    // BoxedInline
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (BoxedInline<$ffi_name:ty>);

        match fn {
            $(
            copy => |$copy_arg:ident| $copy_expr:expr,
            free => |$free_arg:ident| $free_expr:expr,
            )?
            $(
            init => |$init_arg:ident| $init_expr:expr,
            copy_into => |$copy_into_arg_dest:ident, $copy_into_arg_src:ident| $copy_into_expr:expr,
            clear => |$clear_arg:ident| $clear_expr:expr,
            )?
            $(
            type_ => || $get_type_expr:expr,
            )?
        }
    ) => {
        $crate::glib_boxed_inline_wrapper!(
            [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, $ffi_name
            $(, @copy $copy_arg $copy_expr, @free $free_arg $free_expr)?
            $(, @init $init_arg $init_expr, @copy_into $copy_into_arg_dest $copy_into_arg_src $copy_into_expr, @clear $clear_arg $clear_expr)?
            $(, @type_ $get_type_expr)?
        );
    };

    // BoxedInline
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (BoxedInline<$ffi_name:ty>);
    ) => {
        $crate::glib_boxed_inline_wrapper!(
            [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, $ffi_name
        );
    };

    // Shared
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (Shared<$ffi_name:ty>);

        match fn {
            ref => |$ref_arg:ident| $ref_expr:expr,
            unref => |$unref_arg:ident| $unref_expr:expr,
            $(
            type_ => || $get_type_expr:expr,
            )?
        }
    ) => {
        $crate::glib_shared_wrapper!(
            [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, $ffi_name,
            @ref $ref_arg $ref_expr, @unref $unref_arg $unref_expr
            $(, @type_ $get_type_expr)?
        );
    };

    // Object, no parents
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (Object<$ffi_name:ty $(, $ffi_class_name:ty)?>) $(@implements $($implements:path),+)?;

        match fn {
            type_ => || $get_type_expr:expr,
        }
    ) => {
        $crate::glib_object_wrapper!(
            @object [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, *mut std::os::raw::c_void, (), $ffi_name,
            $( @ffi_class $ffi_class_name ,)?
            @type_ $get_type_expr,
            @extends [],
            @implements [$($($implements),+)?]
        );
    };

    // Object, parents
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (Object<$ffi_name:ty $(, $ffi_class_name:ty)?>) @extends $($extends:path),+ $(, @implements $($implements:path),+)?;

        match fn {
            type_ => || $get_type_expr:expr,
        }
    ) => {
        $crate::glib_object_wrapper!(
            @object [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, *mut std::os::raw::c_void, (), $ffi_name,
            $( @ffi_class $ffi_class_name ,)?
            @type_ $get_type_expr,
            @extends [$($extends),+],
            @implements [$($($implements),+)?]
        );
    };

    // ObjectSubclass, no parents
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (ObjectSubclass<$subclass:ty>) $(@implements $($implements:path),+)?;
    ) => {
        $crate::glib_object_wrapper!(
            @object_subclass [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, $subclass,
            @extends [],
            @implements [$($($implements),+)?]
        );
    };

    // ObjectSubclass, parents
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (ObjectSubclass<$subclass:ty>) @extends $($extends:path),+ $(, @implements $($implements:path),+)?;
    ) => {
        $crate::glib_object_wrapper!(
            @object_subclass [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, $subclass,
            @extends [$($extends),+],
            @implements [$($($implements),+)?]
        );
    };

    // Interface
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (Interface<$ffi_name:ty $(, $ffi_class_name:ty)?>) $(@requires $($requires:path),+)?;

        match fn {
            type_ => || $get_type_expr:expr,
        }
    ) => {
        $crate::glib_object_wrapper!(
            @interface [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, *mut std::os::raw::c_void, $ffi_name,
            $( @ffi_class $ffi_class_name ,)?
            @type_ $get_type_expr,
            @requires [$( $($requires),+ )?]
        );
    };

    // ObjectInterface
    (
        $(#[$attr:meta])*
        $visibility:vis struct $name:ident $(<$($generic:ident $(: $bound:tt $(+ $bound2:tt)*)?),+>)? (ObjectInterface<$iface_name:ty>) $(@requires $($requires:path),+)?;
    ) => {
        $crate::glib_object_wrapper!(
            @object_interface [$($attr)*] $visibility $name $(<$($generic $(: $bound $(+ $bound2)*)?),+>)?, $iface_name,
            @type_ $crate::translate::IntoGlib::into_glib(<$iface_name as $crate::subclass::interface::ObjectInterfaceType>::type_()),
            @requires [$( $($requires),+ )?]
        );
    };
}