Add gio::FileEnumerator subclass

Signed-off-by: fbrouille <[email protected]>

Author: fbrouille

gio/src/subclass/file_enumerator.rs

@@ -0,0 +1,154 @@
+// Take a look at the license at the top of the repository in the LICENSE file.
+
+use glib::{prelude::*, subclass::prelude::*, translate::*, Error};
+
+use crate::{ffi, traits::FileEnumeratorExt, Cancellable, FileEnumerator, FileInfo, IOErrorEnum};
+
+// Support custom implementation of virtual functions defined in `gio::ffi::GFileEnumeratorClass` except pairs `xxx_async/xxx_finish` for which GIO provides a default implementation.
+pub trait FileEnumeratorImpl: ObjectImpl + ObjectSubclass<Type: IsA<FileEnumerator>> {
+    fn next_file(&self, cancellable: Option<&Cancellable>) -> Result<Option<FileInfo>, Error> {
+        self.parent_next_file(cancellable)
+    }
+
+    fn close(&self, cancellable: Option<&Cancellable>) -> Result<(), Error> {
+        self.parent_close(cancellable)
+    }
+}
+
+// Support parent implementation of virtual functions defined in `gio::ffi::GFileEnumeratorClass` except pairs `xxx_async/xxx_finish` for which GIO provides a default implementation.
+pub trait FileEnumeratorImplExt: FileEnumeratorImpl {
+    fn parent_next_file(
+        &self,
+        cancellable: Option<&Cancellable>,
+    ) -> Result<Option<FileInfo>, Error> {
+        if self.obj().is_closed() {
+            Err(Error::new::<IOErrorEnum>(
+                IOErrorEnum::Closed,
+                "Enumerator is closed",
+            ))
+        } else {
+            unsafe {
+                let data = Self::type_data();
+                let parent_class = data.as_ref().parent_class() as *const ffi::GFileEnumeratorClass;
+
+                let f = (*parent_class)
+                    .next_file
+                    .expect("No parent class implementation for \"next_file\"");
+
+                let mut error = std::ptr::null_mut();
+                let res = f(
+                    self.obj()
+                        .unsafe_cast_ref::<FileEnumerator>()
+                        .to_glib_none()
+                        .0,
+                    cancellable.as_ref().to_glib_none().0,
+                    &mut error,
+                );
+                if error.is_null() {
+                    Ok(from_glib_full(res))
+                } else {
+                    Err(from_glib_full(error))
+                }
+            }
+        }
+    }
+
+    fn parent_close(&self, cancellable: Option<&Cancellable>) -> Result<(), Error> {
+        unsafe {
+            let data = Self::type_data();
+            let parent_class = data.as_ref().parent_class() as *const ffi::GFileEnumeratorClass;
+
+            let f = (*parent_class)
+                .close_fn
+                .expect("No parent class implementation for \"close_fn\"");
+
+            // get the corresponding object instance without checking the reference count because the object might just be finalized.
+            let obj = {
+                let offset = -data.as_ref().impl_offset();
+                let ptr = self as *const Self as usize;
+                let ptr = if offset < 0 {
+                    ptr - (-offset) as usize
+                } else {
+                    ptr + offset as usize
+                } as *const <Self::Type as ObjectType>::GlibType;
+                glib::BorrowedObject::<Self::Type>::new(mut_override(ptr))
+            };
+
+            let mut error = std::ptr::null_mut();
+            let is_ok = f(
+                obj.unsafe_cast_ref::<FileEnumerator>().to_glib_none().0,
+                cancellable.as_ref().to_glib_none().0,
+                &mut error,
+            );
+            debug_assert_eq!(is_ok == glib::ffi::GFALSE, !error.is_null());
+            if error.is_null() {
+                Ok(())
+            } else {
+                Err(from_glib_full(error))
+            }
+        }
+    }
+}
+
+impl<T: FileEnumeratorImpl> FileEnumeratorImplExt for T {}
+
+// Implement virtual functions defined in `gio::ffi::GFileEnumeratorClass` except pairs `xxx_async/xxx_finish` for which GIO provides a default implementation.
+unsafe impl<T: FileEnumeratorImpl> IsSubclassable<T> for FileEnumerator {
+    fn class_init(class: &mut ::glib::Class<Self>) {
+        Self::parent_class_init::<T>(class);
+
+        let klass = class.as_mut();
+        klass.next_file = Some(next_file::<T>);
+        klass.close_fn = Some(close_fn::<T>);
+        // `GFileEnumerator` already implements `xxx_async/xxx_finish` vfuncs and this should be ok.
+        // TODO: when needed, override the `GFileEnumerator` implementation of the following vfuncs:
+        // klass.next_files_async = Some(next_files_async::<T>);
+        // klass.next_files_finish = Some(next_files_finish::<T>);
+        // klass.close_async = Some(close_async::<T>);
+        // klass.close_finish = Some(close_finish::<T>);
+    }
+}
+
+unsafe extern "C" fn next_file<T: FileEnumeratorImpl>(
+    enumerator: *mut ffi::GFileEnumerator,
+    cancellable: *mut ffi::GCancellable,
+    error: *mut *mut glib::ffi::GError,
+) -> *mut ffi::GFileInfo {
+    let instance = &*(enumerator as *mut T::Instance);
+    let imp = instance.imp();
+    let cancellable = Option::<Cancellable>::from_glib_none(cancellable);
+
+    let res = imp.next_file(cancellable.as_ref());
+
+    match res {
+        Ok(fileinfo) => fileinfo.to_glib_full(),
+        Err(err) => {
+            if !error.is_null() {
+                *error = err.to_glib_full()
+            }
+            std::ptr::null_mut()
+        }
+    }
+}
+
+unsafe extern "C" fn close_fn<T: FileEnumeratorImpl>(
+    enumerator: *mut ffi::GFileEnumerator,
+    cancellable: *mut ffi::GCancellable,
+    error: *mut *mut glib::ffi::GError,
+) -> glib::ffi::gboolean {
+    let instance = &*(enumerator as *mut T::Instance);
+    let imp = instance.imp();
+    let cancellable = Option::<Cancellable>::from_glib_none(cancellable);
+
+    let res = imp.close(cancellable.as_ref());
+
+    match res {
+        Ok(_) => true.into_glib(),
+        Err(err) => {
+            if !error.is_null() {
+                *error = err.to_glib_full()
+            }
+            false.into_glib()
+        }
+    }
+}

gio/src/subclass/mod.rs

@@ -4,6 +4,7 @@ mod action_group;
 mod action_map;
 mod application;
 mod async_initable;
+mod file_enumerator;
 mod file_monitor;
 mod initable;
 mod input_stream;
@@ -24,6 +25,7 @@ pub mod prelude {
         action_map::{ActionMapImpl, ActionMapImplExt},
         application::{ApplicationImpl, ApplicationImplExt},
         async_initable::{AsyncInitableImpl, AsyncInitableImplExt},
+        file_enumerator::{FileEnumeratorImpl, FileEnumeratorImplExt},
         file_monitor::{FileMonitorImpl, FileMonitorImplExt},
         initable::{InitableImpl, InitableImplExt},
         input_stream::{InputStreamImpl, InputStreamImplExt},