css, gfx, sub: Eliminate many copies

src/rust-css

@@ -1 +1 @@
-Subproject commit b1ac22d98de7c6e622709ebd3ae2bd63a762b2b2
+Subproject commit f5ebbe2787cec856ce52c1aabec28e30939b9b35

src/servo-gfx/quartz/font.rs

@@ -146,15 +146,13 @@ pub impl QuartzFontHandle : FontHandleMethods {
     }
 
     fn glyph_index(codepoint: char) -> Option<GlyphIndex> {
-        let characters: ~[UniChar] = ~[codepoint as UniChar];
+        let characters: [UniChar * 1] = [codepoint as UniChar];
-        let glyphs: ~[mut CGGlyph] = ~[mut 0 as CGGlyph];
+        let glyphs: [mut CGGlyph * 1] = [mut 0 as CGGlyph];
         let count: CFIndex = 1;
 
-        let result = do vec::as_imm_buf(characters) |character_buf, _l| {
+        let result = self.ctfont.get_glyphs_for_characters(ptr::to_unsafe_ptr(&characters[0]),
-            do vec::as_imm_buf(glyphs) |glyph_buf, _l| {
+                                                           ptr::to_unsafe_ptr(&glyphs[0]),
-                self.ctfont.get_glyphs_for_characters(character_buf, glyph_buf, count)
+                                                           count);
-            }
-        };
 
         if !result {
             // No glyph for this character
@@ -166,13 +164,15 @@ pub impl QuartzFontHandle : FontHandleMethods {
     }
 
     fn glyph_h_advance(glyph: GlyphIndex) -> Option<FractionalPixel> {
-        let glyphs = ~[glyph as CGGlyph];
+        let glyphs = [glyph as CGGlyph];
-        let advance = do vec::as_imm_buf(glyphs) |glyph_buf, _l| {
+        unsafe {
-            self.ctfont.get_advances_for_glyphs(kCTFontDefaultOrientation, glyph_buf, ptr::null(), 1)
+            let advance = self.ctfont.get_advances_for_glyphs(kCTFontDefaultOrientation,
-        };
+                                                              ptr::to_unsafe_ptr(&glyphs[0]),
-
+                                                              ptr::null(),
+                                                              1);
             return Some(advance as FractionalPixel);
         }
+    }
 
     fn get_metrics() -> FontMetrics {
         let bounding_rect: CGRect = self.ctfont.bounding_box();

src/servo/css/select_handler.rs

@@ -71,10 +71,10 @@ impl NodeSelectHandler: SelectHandler<Node> {
         self.parent_node(node).is_none()
     }
 
-    fn node_id(node: &Node) -> Option<~str> {
+    fn with_node_id<R>(node: &Node, f: &fn(Option<&str>) -> R) -> R {
         do node.read |data| {
             match *data.kind {
-                Element(ref data) => data.get_attr("id"),
+                Element(ref data) => data.with_attr("id", f),
                 _ => fail ~"attempting to style non-element node"
             }
         }