[librsvg] librsvg_crate: Take all gio arguments as IsA<SomeGioType> generics

[Federico Mena Quintero <federico src gnome org>]

commit 710172f009e6163d87f639240f49af8d4722f143
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Aug 14 14:45:30 2019 -0500

    librsvg_crate: Take all gio arguments as IsA<SomeGioType> generics
    
    This lets the caller avoid conversions; we'll do the conversions
    internally to concrete types.

 librsvg_crate/examples/render_to_file.rs |  2 +-
 librsvg_crate/src/lib.rs                 | 16 +++++++++-------
 librsvg_crate/tests/utils/mod.rs         |  2 +-
 3 files changed, 11 insertions(+), 9 deletions(-)
---
diff --git a/librsvg_crate/examples/render_to_file.rs b/librsvg_crate/examples/render_to_file.rs
index 3dbce400..4976460a 100644
--- a/librsvg_crate/examples/render_to_file.rs
+++ b/librsvg_crate/examples/render_to_file.rs
@@ -6,7 +6,7 @@ fn main() {
     let bytes = glib::Bytes::from_static(include_bytes!("org.gnome.Epiphany.svg"));
     let stream = gio::MemoryInputStream::new_from_bytes(&bytes);
     let handle = librsvg::Loader::new()
-        .read_stream(&stream, None, None::<&gio::Cancellable>)
+        .read_stream(&stream, None::<&gio::File>, None::<&gio::Cancellable>)
         .unwrap();
     let renderer = librsvg::CairoRenderer::new(&handle);
 
diff --git a/librsvg_crate/src/lib.rs b/librsvg_crate/src/lib.rs
index bdec4e50..b85fc24f 100644
--- a/librsvg_crate/src/lib.rs
+++ b/librsvg_crate/src/lib.rs
@@ -242,16 +242,16 @@ impl Loader {
     /// use librsvg::Loader;
     ///
     /// let svg_handle = Loader::new()
-    ///     .read_file(&gio::File::new_for_path("hello.svg"), None)
+    ///     .read_file(&gio::File::new_for_path("hello.svg"), None::<&gio::Cancellable>)
     ///     .unwrap();
     /// ```
-    pub fn read_file<P: IsA<Cancellable>>(
+    pub fn read_file<F: IsA<gio::File>, P: IsA<Cancellable>>(
         self,
-        file: &gio::File,
+        file: &F,
         cancellable: Option<&P>,
     ) -> Result<SvgHandle, LoadingError> {
         let stream = file.read(cancellable)?;
-        self.read_stream(&stream, Some(&file), cancellable)
+        self.read_stream(&stream, Some(file), cancellable)
     }
 
     /// Reads an SVG stream from a `gio::InputStream`.
@@ -266,14 +266,16 @@ impl Loader {
     /// URL where this SVG got loaded from.
     ///
     /// The `cancellable` can be used to cancel loading from another thread.
-    pub fn read_stream<S: IsA<gio::InputStream>, P: IsA<Cancellable>>(
+    pub fn read_stream<S: IsA<gio::InputStream>, F: IsA<gio::File>, P: IsA<Cancellable>>(
         self,
         stream: &S,
-        base_file: Option<&gio::File>,
+        base_file: Option<&F>,
         cancellable: Option<&P>,
     ) -> Result<SvgHandle, LoadingError> {
+        let base_file = base_file.map(|f| f.as_ref());
+
         let base_url = if let Some(base_file) = base_file {
-            Some(url_from_file(&base_file)?)
+            Some(url_from_file(base_file)?)
         } else {
             None
         };
diff --git a/librsvg_crate/tests/utils/mod.rs b/librsvg_crate/tests/utils/mod.rs
index b1bb4a06..c76d1223 100644
--- a/librsvg_crate/tests/utils/mod.rs
+++ b/librsvg_crate/tests/utils/mod.rs
@@ -23,7 +23,7 @@ pub fn load_svg(input: &'static [u8]) -> SvgHandle {
     let bytes = glib::Bytes::from_static(input);
     let stream = gio::MemoryInputStream::new_from_bytes(&bytes);
 
-    Loader::new().read_stream(&stream, None, None::<&gio::Cancellable>).unwrap()
+    Loader::new().read_stream(&stream, None::<&gio::File>, None::<&gio::Cancellable>).unwrap()
 }
 
 #[derive(Copy, Clone)]