layout: If the border style is "none", treat its width as 0.

Closes #1383.

src/components/main/layout/block.rs

@@ -763,17 +763,17 @@ impl Flow for BlockFlow {
     }
 
     fn debug_str(&self) -> ~str {
-        if self.is_root {
-            ~"BlockFlow(root)"
+        let txt = if self.is_float() {
+            ~"FloatFlow: "
+        } else if self.is_root {
+            ~"RootFlow: "
         } else {
-            let txt = if self.is_float() { ~"FloatFlow: " } else { ~"BlockFlow: " };
-            txt.append(match self.box {
-                Some(ref rb) => {
-                    rb.debug_str()
-                }
-                None => { ~"" }
-            })
-        }
+            ~"BlockFlow: "
+        };
+        txt.append(match self.box {
+            Some(ref rb) => rb.debug_str(),
+            None => ~"",
+        })
     }
 }
 

src/components/main/layout/box.rs

@@ -281,10 +281,23 @@ impl Box {
     ///
     /// FIXME(pcwalton): This should not be necessary. Just go to the style.
     pub fn compute_borders(&self, style: &ComputedValues) {
-        self.border.set(SideOffsets2D::new(style.Border.border_top_width,
-                                           style.Border.border_right_width,
-                                           style.Border.border_bottom_width,
-                                           style.Border.border_left_width))
+        #[inline]
+        fn width(width: Au, style: border_style::T) -> Au {
+            if style == border_style::none {
+                Au(0)
+            } else {
+                width
+            }
+        }
+
+        self.border.set(SideOffsets2D::new(width(style.Border.border_top_width,
+                                                 style.Border.border_top_style),
+                                           width(style.Border.border_right_width,
+                                                 style.Border.border_right_style),
+                                           width(style.Border.border_bottom_width,
+                                                 style.Border.border_bottom_style),
+                                           width(style.Border.border_left_width,
+                                                 style.Border.border_left_style)))
     }
 
     /// Populates the box model padding parameters from the given computed style.
@@ -983,12 +996,33 @@ impl Box {
 
     /// Returns a debugging string describing this box.
     pub fn debug_str(&self) -> ~str {
-        match self.specific {
-            GenericBox => "(GenericBox)",
-            ImageBox(_) => "(ImageBox)",
-            ScannedTextBox(_) => "(ScannedTextBox)",
-            UnscannedTextBox(_) => "(UnscannedTextBox)",
-        }.to_str()
+        let class_name = match self.specific {
+            GenericBox => "GenericBox",
+            ImageBox(_) => "ImageBox",
+            ScannedTextBox(_) => "ScannedTextBox",
+            UnscannedTextBox(_) => "UnscannedTextBox",
+        };
+
+        format!("({}{}{}{})",
+                class_name,
+                self.side_offsets_debug_string("b", self.border.get()),
+                self.side_offsets_debug_string("p", self.padding.get()),
+                self.side_offsets_debug_string("m", self.margin.get()))
+    }
+
+    /// A helper function to return a debug string describing the side offsets for one of the rect
+    /// box model properties (border, padding, or margin).
+    fn side_offsets_debug_string(&self, name: &str, value: SideOffsets2D<Au>) -> ~str {
+        let zero: SideOffsets2D<Au> = Zero::zero();
+        if value == zero {
+            return "".to_str()
+        }
+        format!(" {}{},{},{},{}",
+                name,
+                *value.top,
+                *value.right,
+                *value.bottom,
+                *value.left)
     } 
 }
 

src/components/main/layout/layout_task.rs

@@ -448,15 +448,15 @@ impl LayoutTask {
         });
         layout_root.traverse_postorder(&mut ComputeDamageTraversal.clone());
 
-        debug!("layout: constructed Flow tree");
-        debug!("{:?}", layout_root.dump());
-
         // Perform the primary layout passes over the flow tree to compute the locations of all
         // the boxes.
         do profile(time::LayoutMainCategory, self.profiler_chan.clone()) {
             self.solve_constraints(layout_root, &mut layout_ctx)
         }
 
+        debug!("layout: constraint solving done:");
+        debug!("{:?}", layout_root.dump());
+
         // Build the display list if necessary, and send it to the renderer.
         if data.goal == ReflowForDisplay {
             do profile(time::LayoutDispListBuildCategory, self.profiler_chan.clone()) {

src/test/ref/basic.list

@@ -15,3 +15,4 @@
 == visibility_hidden.html visibility_hidden_ref.html
 == root_height_a.html root_height_b.html
 == png_rgba_colorspace_a.html png_rgba_colorspace_b.html
+== border_style_none_a.html border_style_none_b.html

src/test/ref/border_style_none_a.html

@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+html {
+    margin: 0;
+    padding: 0;
+    background-color: blue;
+}
+body {
+    margin: 0;
+    padding: 0;
+    border-top-width: 3px;
+    border-top-style: none;
+}
+</style>
+</head>
+<body><img src="png_rgba_colorspace_a.png"></body>
+</html>
+

src/test/ref/border_style_none_b.html

@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+html {
+    margin: 0;
+    padding: 0;
+    background-color: blue;
+}
+body {
+    margin: 0;
+    padding: 0;
+    border-top-width: 0px;
+}
+</style>
+</head>
+<body><img src="png_rgba_colorspace_a.png"></body>
+</html>
+