gio: Add LoadableIcon subclassing support

gio/src/subclass/loadable_icon.rs

@@ -0,0 +1,263 @@
+// Take a look at the license at the top of the repository in the LICENSE file.
+
+use std::{future::Future, pin::Pin};
+
+use crate::{
+    subclass::prelude::*, AsyncResult, Cancellable, GioFuture, InputStream, LoadableIcon, LocalTask,
+};
+use glib::{prelude::*, translate::*, GString};
+
+pub trait LoadableIconImpl: IconImpl {
+    fn load(
+        &self,
+        size: i32,
+        cancellable: Option<&Cancellable>,
+    ) -> Result<(InputStream, Option<GString>), glib::Error> {
+        self.parent_load(size, cancellable)
+    }
+
+    fn load_future(
+        &self,
+        size: i32,
+    ) -> Pin<Box<dyn Future<Output = Result<(InputStream, Option<GString>), glib::Error>> + 'static>>
+    {
+        self.parent_load_future(size)
+    }
+}
+
+pub trait LoadableIconImplExt: ObjectSubclass {
+    fn parent_load(
+        &self,
+        size: i32,
+        cancellable: Option<&Cancellable>,
+    ) -> Result<(InputStream, Option<GString>), glib::Error>;
+
+    fn parent_load_async<C>(&self, size: i32, cancellable: Option<&Cancellable>, callback: C)
+    where
+        C: FnOnce(Result<(InputStream, Option<GString>), glib::Error>) + 'static;
+
+    fn parent_load_future(
+        &self,
+        size: i32,
+    ) -> Pin<Box<dyn Future<Output = Result<(InputStream, Option<GString>), glib::Error>> + 'static>>;
+}
+
+impl<T: LoadableIconImpl> LoadableIconImplExt for T {
+    fn parent_load(
+        &self,
+        size: i32,
+        cancellable: Option<&Cancellable>,
+    ) -> Result<(InputStream, Option<GString>), glib::Error> {
+        unsafe {
+            let type_data = Self::type_data();
+            let parent_iface = type_data.as_ref().parent_interface::<LoadableIcon>()
+                as *const ffi::GLoadableIconIface;
+
+            let func = (*parent_iface)
+                .load
+                .expect("No parent iface implementation for \"load\"");
+            let mut err = std::ptr::null_mut();
+            let mut string = std::ptr::null_mut();
+            let stream = func(
+                self.obj()
+                    .unsafe_cast_ref::<LoadableIcon>()
+                    .to_glib_none()
+                    .0,
+                size,
+                &mut string,
+                cancellable.to_glib_none().0,
+                &mut err,
+            );
+            if err.is_null() {
+                Ok((from_glib_full(stream), from_glib_full(string)))
+            } else {
+                Err(from_glib_full(err))
+            }
+        }
+    }
+
+    fn parent_load_async<C>(&self, size: i32, cancellable: Option<&Cancellable>, callback: C)
+    where
+        C: FnOnce(Result<(InputStream, Option<GString>), glib::Error>) + 'static,
+    {
+        unsafe {
+            let main_context = glib::MainContext::ref_thread_default();
+            let is_main_context_owner = main_context.is_owner();
+            let has_acquired_main_context = (!is_main_context_owner)
+                .then(|| main_context.acquire().ok())
+                .flatten();
+            assert!(
+                is_main_context_owner || has_acquired_main_context.is_some(),
+                "Async operations only allowed if the thread is owning the MainContext"
+            );
+
+            let type_data = T::type_data();
+            let parent_iface = type_data.as_ref().parent_interface::<LoadableIcon>()
+                as *const ffi::GLoadableIconIface;
+            let f = (*parent_iface)
+                .load_async
+                .expect("no parent \"load_async\" implementation");
+            let finish = (*parent_iface)
+                .load_finish
+                .expect("no parent \"load_finish\" implementation");
+
+            let user_data: Box<(glib::thread_guard::ThreadGuard<C>, _)> =
+                Box::new((glib::thread_guard::ThreadGuard::new(callback), finish));
+
+            unsafe extern "C" fn parent_load_async_trampoline<R>(
+                source_object_ptr: *mut glib::gobject_ffi::GObject,
+                res: *mut ffi::GAsyncResult,
+                user_data: glib::ffi::gpointer,
+            ) where
+                R: FnOnce(Result<(InputStream, Option<GString>), glib::Error>) + 'static,
+            {
+                let mut error = std::ptr::null_mut();
+                let cb: Box<(
+                    glib::thread_guard::ThreadGuard<R>,
+                    fn(
+                        *mut ffi::GLoadableIcon,
+                        *mut ffi::GAsyncResult,
+                        *mut *mut libc::c_char,
+                        *mut *mut glib::ffi::GError,
+                    ) -> *mut ffi::GInputStream,
+                )> = Box::from_raw(user_data as *mut _);
+                let mut typeptr = std::ptr::null_mut();
+                let stream = cb.1(source_object_ptr as _, res, &mut typeptr, &mut error);
+                let result = if error.is_null() {
+                    Ok((from_glib_full(stream), from_glib_full(typeptr)))
+                } else {
+                    Err(from_glib_full(error))
+                };
+                let cb = cb.0.into_inner();
+                cb(result);
+            }
+
+            let callback = parent_load_async_trampoline::<C>;
+            f(
+                self.obj()
+                    .unsafe_cast_ref::<LoadableIcon>()
+                    .to_glib_none()
+                    .0,
+                size,
+                cancellable.to_glib_none().0,
+                Some(callback),
+                Box::into_raw(user_data) as *mut _,
+            );
+        }
+    }
+
+    fn parent_load_future(
+        &self,
+        size: i32,
+    ) -> Pin<Box<dyn Future<Output = Result<(InputStream, Option<GString>), glib::Error>> + 'static>>
+    {
+        Box::pin(GioFuture::new(
+            &self.ref_counted(),
+            move |imp, cancellable, send| {
+                imp.parent_load_async(size, Some(cancellable), move |res| {
+                    send.resolve(res);
+                });
+            },
+        ))
+    }
+}
+
+unsafe impl<T: LoadableIconImpl> IsImplementable<T> for LoadableIcon {
+    fn interface_init(iface: &mut glib::Interface<Self>) {
+        let iface = iface.as_mut();
+
+        iface.load = Some(icon_load::<T>);
+        iface.load_async = Some(icon_load_async::<T>);
+        iface.load_finish = Some(icon_load_finish::<T>);
+    }
+}
+
+unsafe extern "C" fn icon_load<T: LoadableIconImpl>(
+    icon: *mut ffi::GLoadableIcon,
+    size: i32,
+    typeptr: *mut *mut libc::c_char,
+    cancellableptr: *mut ffi::GCancellable,
+    errorptr: *mut *mut glib::ffi::GError,
+) -> *mut ffi::GInputStream {
+    let instance = &*(icon as *mut T::Instance);
+    let imp = instance.imp();
+
+    let cancellable: Borrowed<Option<Cancellable>> = from_glib_borrow(cancellableptr);
+
+    let ret = imp.load(size, cancellable.as_ref().as_ref());
+    match ret {
+        Ok((stream, icon_type)) => {
+            if !typeptr.is_null() {
+                *typeptr = icon_type.to_glib_none().0;
+            }
+
+            stream.to_glib_full()
+        }
+        Err(err) => {
+            *errorptr = err.into_glib_ptr();
+            *typeptr = std::ptr::null_mut();
+
+            std::ptr::null_mut()
+        }
+    }
+}
+
+#[derive(Clone, glib::Boxed)]
+#[boxed_type(name = "GLoadableIconReturnType")]
+// Needed for having the required Value traits by GTask API
+struct LoadableIconReturnType(InputStream, Option<GString>);
+
+unsafe extern "C" fn icon_load_async<T: LoadableIconImpl>(
+    icon: *mut ffi::GLoadableIcon,
+    size: i32,
+    cancellableptr: *mut ffi::GCancellable,
+    callbackptr: ffi::GAsyncReadyCallback,
+    dataptr: glib::ffi::gpointer,
+) {
+    let instance = &*(icon as *mut T::Instance);
+    let imp = instance.imp();
+    let wrap: LoadableIcon = from_glib_none(icon);
+    let cancellable: Option<Cancellable> = from_glib_none(cancellableptr);
+
+    let closure = move |task: LocalTask<LoadableIconReturnType>,
+                        source_object: Option<&glib::Object>| {
+        let result: *mut ffi::GAsyncResult = task.upcast_ref::<AsyncResult>().to_glib_none().0;
+        let source_object: *mut glib::gobject_ffi::GObject = source_object.to_glib_none().0;
+        callbackptr.unwrap()(source_object, result, dataptr)
+    };
+
+    let t = LocalTask::new(
+        Some(wrap.upcast_ref::<glib::Object>()),
+        cancellable.as_ref(),
+        closure,
+    );
+
+    glib::MainContext::default().spawn_local(async move {
+        let res = imp.load_future(size).await;
+        t.return_result(res.map(|(s, t)| LoadableIconReturnType(s, t)));
+    });
+}
+
+unsafe extern "C" fn icon_load_finish<T: LoadableIconImpl>(
+    _icon: *mut ffi::GLoadableIcon,
+    resultptr: *mut ffi::GAsyncResult,
+    typeptr: *mut *mut libc::c_char,
+    errorptr: *mut *mut glib::ffi::GError,
+) -> *mut ffi::GInputStream {
+    let res: AsyncResult = from_glib_none(resultptr);
+    let t = res.downcast::<LocalTask<LoadableIconReturnType>>().unwrap();
+    let ret = t.propagate();
+    match ret {
+        Ok(rt) => {
+            let (stream, icon_type) = (rt.0, rt.1);
+            if !typeptr.is_null() {
+                *typeptr = icon_type.to_glib_full();
+            }
+            stream.to_glib_full()
+        }
+        Err(err) => {
+            *errorptr = err.into_glib_ptr();
+            std::ptr::null_mut()
+        }
+    }
+}

gio/src/subclass/mod.rs

@@ -11,6 +11,7 @@ mod initable;
 mod input_stream;
 mod io_stream;
 mod list_model;
+mod loadable_icon;
 mod output_stream;
 mod seekable;
 
@@ -32,6 +33,7 @@ pub mod prelude {
         input_stream::{InputStreamImpl, InputStreamImplExt},
         io_stream::{IOStreamImpl, IOStreamImplExt},
         list_model::{ListModelImpl, ListModelImplExt},
+        loadable_icon::{LoadableIconImpl, LoadableIconImplExt},
         output_stream::{OutputStreamImpl, OutputStreamImplExt},
         seekable::{SeekableImpl, SeekableImplExt},
     };