servo: Render to PNG file when using -o flag

Source-Repo: https://github.com/servo/servo
Source-Revision: 7a8305dc163b1934df948aa252cbc99e69315f2f

servo/src/servo/engine.rs

@@ -0,0 +1,36 @@
+import gfx::renderer;
+
+enum msg {
+    load_url(str),
+    exit(comm::chan<()>)
+}
+
+fn engine<S: renderer::sink send>(sink: S) -> comm::chan<msg> {
+
+    task::spawn_listener::<msg> {|self_ch|
+        // The renderer
+        let renderer = renderer::renderer(sink);
+
+        // The layout task
+        let layout = layout::layout::layout(renderer);
+
+        // The content task
+        let content = content::content(layout);
+
+        loop {
+            alt self_ch.recv() {
+              load_url(url) { content.send(content::parse(url)) }
+              exit(sender) {
+                content.send(content::exit);
+                layout.send(layout::layout::exit);
+                listen {|resp_ch|
+                    renderer.send(renderer::exit(resp_ch));
+                    resp_ch.recv();
+                }
+                sender.send(());
+                break;
+              }
+            }
+        }
+    }
+}

servo/src/servo/gfx/pngsink.rs

@@ -41,9 +41,11 @@ fn pngsink(output: chan<[u8]>) -> chan<msg> {
         loop {
             alt po.recv() {
               begin_drawing(sender) {
+                #debug("pngsink: begin_drawing");
                 sender.send(draw_target);
               }
               draw(sender, dt) {
+                #debug("pngsink: draw");
                 do_draw(sender, dt, output, cairo_surf);
               }
               exit { break }

servo/src/servo/opts.rs

@@ -12,7 +12,7 @@ type opts = {
 
 enum render_mode {
     screen,
-    file(str)
+    png(str)
 }
 
 fn from_cmdline_args(args: [str]) -> opts {
@@ -36,7 +36,7 @@ fn from_cmdline_args(args: [str]) -> opts {
     };
 
     let render_mode = alt getopts::opt_maybe_str(match, "o") {
-      some(output_file) { file(output_file) }
+      some(output_file) { png(output_file) }
       none { screen }
     };
 

servo/src/servo/servo.rc

@@ -50,3 +50,4 @@ mod util {
 
 mod content;
 mod opts;
+mod engine;

servo/src/servo/servo.rs

@@ -11,41 +11,73 @@ fn main(args: [str]) {
 
 fn run(opts: opts::opts) {
 
+    alt opts.render_mode {
+      opts::screen {
+        run_pipeline_screen(opts.urls)
+      }
+      opts::png(outfile) {
+        assert opts.urls.is_not_empty();
+        if opts.urls.len() > 1u {
+            fail "servo asks that you stick to a single URL in PNG output mode"
+        }
+        run_pipeline_png(opts.urls.head(), outfile)
+      }
+    }
+}
+
+fn run_pipeline_screen(urls: [str]) {
+
+    // Use the platform thread as the renderer sink
+    import osmain::gfxsink;
+
     // The platform event handler thread
     let osmain = osmain::osmain();
 
-    // The renderer
-    let renderer = {
-        // Use the platform thread as the renderer sink
-        import osmain::gfxsink;
-        renderer::renderer(osmain)
-    };
-
-    // The layout task
-    let layout = layout::layout::layout(renderer);
-
-    // The content task
-    let content = content::content(layout);
+    // Create a serve instance
+    let engine = engine::engine(osmain);
 
     // Send each file to render then wait for keypress
-    for opts.urls.each { |filename|
-        #debug["master: Sending filename `%s`", filename];
-        content.send(content::parse(filename));
-        #debug["master: Waiting for keypress"];
     listen {|key_ch|
         osmain.send(platform::osmain::add_key_handler(key_ch));
+
+        for urls.each { |filename|
+            #debug["master: Sending filename `%s`", filename];
+            engine.send(engine::load_url(filename));
+            #debug["master: Waiting for keypress"];
             key_ch.recv();
         }
     }
 
     // Shut everything down
     #debug["master: Shut down"];
-    content.send(content::exit);
-    layout.send(layout::layout::exit);
-
-    listen {|wait_ch|
-        renderer.send(gfx::renderer::exit(wait_ch));
-        wait_ch.recv();
+    listen {|resp_ch|
+        engine.send(engine::exit(resp_ch));
+        resp_ch.recv();
     }
     osmain.send(platform::osmain::exit);
 }
+
+fn run_pipeline_png(url: str, outfile: str) {
+
+    // Use a PNG encoder as the graphics sink
+    import gfx::pngsink;
+    import pngsink::pngsink;
+
+    listen {|pngdata|
+        let sink = pngsink::pngsink(pngdata);
+        let engine = engine::engine(sink);
+        engine.send(engine::load_url(url));
+        alt io::buffered_file_writer(outfile) {
+          result::ok(writer) {
+            import io::writer;
+            writer.write(pngdata.recv())
+          }
+          result::err(e) { fail e }
+        }
+        listen {|resp_ch|
+            engine.send(engine::exit(resp_ch));
+            resp_ch.recv();
+        }
+        sink.send(pngsink::exit);
+    }
+}