[librsvg: 25/30] ImageSurface::draw is now generic on the error type

[Marge Bot <marge-bot src gnome org>]

commit 68044cff571715b60b5dfbd38c7a9801aaa66887
Author: Federico Mena Quintero <federico gnome org>
Date:   Mon Jun 21 20:42:11 2021 -0500

    ImageSurface::draw is now generic on the error type
    
    this-is-fine.gif
    
    Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/516>

 src/drawing_ctx.rs                  | 32 +++++++++++++++++++-------------
 src/filters/context.rs              | 28 ++++++++++++----------------
 src/filters/displacement_map.rs     |  2 +-
 src/surface_utils/shared_surface.rs | 13 +++++++++----
 4 files changed, 41 insertions(+), 34 deletions(-)
---
diff --git a/src/drawing_ctx.rs b/src/drawing_ctx.rs
index 67114d35..a196bc70 100644
--- a/src/drawing_ctx.rs
+++ b/src/drawing_ctx.rs
@@ -946,7 +946,10 @@ impl DrawingCtx {
         Ok(surface)
     }
 
-    fn set_gradient(self: &mut DrawingCtx, gradient: &UserSpaceGradient) -> Result<(), cairo::Error> {
+    fn set_gradient(
+        self: &mut DrawingCtx,
+        gradient: &UserSpaceGradient,
+    ) -> Result<(), cairo::Error> {
         let g = match gradient.variant {
             GradientVariant::Linear { x1, y1, x2, y2 } => {
                 cairo::Gradient::clone(&cairo::LinearGradient::new(x1, y1, x2, y2))
@@ -1123,26 +1126,24 @@ impl DrawingCtx {
         height: i32,
         acquired_nodes: &mut AcquiredNodes<'_>,
         paint_source: &UserSpacePaintSource,
-    ) -> Result<SharedImageSurface, cairo::Error> {
+    ) -> Result<SharedImageSurface, RenderingError> {
         let mut surface = ExclusiveImageSurface::new(width, height, SurfaceType::SRgb)?;
 
-        surface.draw(&mut |cr| {
+        surface.draw::<RenderingError>(&mut |cr| {
             let mut temporary_draw_ctx = self.nested(cr);
 
             // FIXME: we are ignoring any error
 
-            let _ = temporary_draw_ctx
-                .set_paint_source(paint_source, acquired_nodes)
-                .map(|had_paint_server| {
-                    if had_paint_server {
-                        temporary_draw_ctx.cr.paint();
-                    }
-                });
+            let had_paint_server =
+                temporary_draw_ctx.set_paint_source(paint_source, acquired_nodes)?;
+            if had_paint_server {
+                temporary_draw_ctx.cr.paint()?;
+            }
 
             Ok(())
         })?;
 
-        surface.share()
+        Ok(surface.share()?)
     }
 
     fn stroke(
@@ -1247,7 +1248,12 @@ impl DrawingCtx {
         )
     }
 
-    fn paint_surface(&mut self, surface: &SharedImageSurface, width: f64, height: f64) -> Result<(), 
cairo::Error> {
+    fn paint_surface(
+        &mut self,
+        surface: &SharedImageSurface,
+        width: f64,
+        height: f64,
+    ) -> Result<(), cairo::Error> {
         let cr = self.cr.clone();
 
         // We need to set extend appropriately, so can't use cr.set_source_surface().
@@ -1421,7 +1427,7 @@ impl DrawingCtx {
         //   https://www.w3.org/TR/compositing-1/#isolation
         let mut surface = ExclusiveImageSurface::new(width, height, SurfaceType::SRgb)?;
 
-        surface.draw(&mut |cr| {
+        surface.draw::<cairo::Error>(&mut |cr| {
             // TODO: apparently DrawingCtx.cr_stack is just a way to store pairs of
             // (surface, transform).  Can we turn it into a DrawingCtx.surface_stack
             // instead?  See what CSS isolation would like to call that; are the pairs just
diff --git a/src/filters/context.rs b/src/filters/context.rs
index 5e778bb9..40cfdffa 100644
--- a/src/filters/context.rs
+++ b/src/filters/context.rs
@@ -204,14 +204,12 @@ impl FilterContext {
         draw_ctx: &mut DrawingCtx,
     ) -> Result<SharedImageSurface, FilterError> {
         let res = self.stroke_paint_surface.get_or_init(|| {
-            draw_ctx
-                .get_paint_source_surface(
-                    self.source_surface.width(),
-                    self.source_surface.height(),
-                    acquired_nodes,
-                    &self.stroke_paint,
-                )
-                .map_err(FilterError::CairoError)
+            Ok(draw_ctx.get_paint_source_surface(
+                self.source_surface.width(),
+                self.source_surface.height(),
+                acquired_nodes,
+                &self.stroke_paint,
+            )?)
         });
 
         res.as_ref().map(|s| s.clone()).map_err(|e| e.clone())
@@ -226,14 +224,12 @@ impl FilterContext {
         draw_ctx: &mut DrawingCtx,
     ) -> Result<SharedImageSurface, FilterError> {
         let res = self.fill_paint_surface.get_or_init(|| {
-            draw_ctx
-                .get_paint_source_surface(
-                    self.source_surface.width(),
-                    self.source_surface.height(),
-                    acquired_nodes,
-                    &self.fill_paint,
-                )
-                .map_err(FilterError::CairoError)
+            Ok(draw_ctx.get_paint_source_surface(
+                self.source_surface.width(),
+                self.source_surface.height(),
+                acquired_nodes,
+                &self.fill_paint,
+            )?)
         });
 
         res.as_ref().map(|s| s.clone()).map_err(|e| e.clone())
diff --git a/src/filters/displacement_map.rs b/src/filters/displacement_map.rs
index 0e51a945..b7aaf865 100644
--- a/src/filters/displacement_map.rs
+++ b/src/filters/displacement_map.rs
@@ -115,7 +115,7 @@ impl DisplacementMap {
             input_1.surface().surface_type(),
         )?;
 
-        surface.draw(&mut |cr| {
+        surface.draw::<cairo::Error>(&mut |cr| {
             for (x, y, displacement_pixel) in Pixels::within(&displacement_surface, bounds) {
                 let get_value = |channel| match channel {
                     ColorChannel::R => displacement_pixel.r,
diff --git a/src/surface_utils/shared_surface.rs b/src/surface_utils/shared_surface.rs
index abe91a27..1fec4f74 100644
--- a/src/surface_utils/shared_surface.rs
+++ b/src/surface_utils/shared_surface.rs
@@ -388,7 +388,12 @@ impl ImageSurface<Shared> {
 
     /// Calls `set_source_surface()` on the given Cairo context.
     #[inline]
-    pub fn set_as_source_surface(&self, cr: &cairo::Context, x: f64, y: f64) -> Result<(), cairo::Error> {
+    pub fn set_as_source_surface(
+        &self,
+        cr: &cairo::Context,
+        x: f64,
+        y: f64,
+    ) -> Result<(), cairo::Error> {
         cr.set_source_surface(&self.surface, x, y)
     }
 
@@ -1345,10 +1350,10 @@ impl ImageSurface<Exclusive> {
 
     /// Draw on the surface using cairo
     #[inline]
-    pub fn draw(
+    pub fn draw<E: From<cairo::Error>>(
         &mut self,
-        draw_fn: &mut dyn FnMut(cairo::Context) -> Result<(), cairo::Error>,
-    ) -> Result<(), cairo::Error> {
+        draw_fn: &mut dyn FnMut(cairo::Context) -> Result<(), E>,
+    ) -> Result<(), E> {
         let cr = cairo::Context::new(&self.surface)?;
         draw_fn(cr)
     }