Implement toy inline layout

src/servo/dom/base.rs

@@ -52,3 +52,4 @@ impl of tree::wr_tree_ops<node> for node_scope {
         self.wr(node) { |n| f(n.tree) }
     }
 }
+

src/servo/dom/rcu.rs

@@ -52,6 +52,9 @@ impl reader_methods<T:send,A> for handle<T,A> {
     }
 
     fn set_aux(p: @A) unsafe {
+        let p2 = p;
+        unsafe::forget(p2); // Bump the reference count.
+
         (**self).rd_aux = ptr::addr_of(*p);
     }
 

src/servo/layout/base.rs

@@ -61,6 +61,22 @@ impl of tree::wr_tree_ops<@box> for btree {
     }
 }
 
+impl layout_methods_priv for @box {
+    #[doc="Dumps the box tree, for debugging, with indentation."]
+    fn dump_indent(indent: uint) {
+        let mut s = "";
+        uint::range(0u, indent) {
+            |_i|
+            s += "    ";
+        }
+
+        s += #fmt("%?", self.kind);
+        #debug["%s", s];
+
+        for btree.each_child(self) { |kid| kid.dump_indent(indent + 1u) }
+    }
+}
+
 impl layout_methods for @box {
     #[doc="The main reflow routine."]
     fn reflow(available_width: au) {
@@ -77,6 +93,36 @@ impl layout_methods for @box {
 
         #debug["reflow_intrinsic size=%?", self.bounds];
     }
+
+    #[doc="Dumps the box tree, for debugging."]
+    fn dump() {
+        self.dump_indent(0u);
+    }
+}
+
+// Debugging
+
+impl node_methods_priv for node {
+    #[doc="Dumps the node tree, for debugging, with indentation."]
+    fn dump_indent(indent: uint) {
+        let mut s = "";
+        uint::range(0u, indent) {
+            |_i|
+            s += "    ";
+        }
+
+        s += #fmt("%?", self.rd({ |n| n.kind }));
+        #debug["%s", s];
+
+        for ntree.each_child(self) { |kid| kid.dump_indent(indent + 1u) }
+    }
+}
+
+impl node_methods for node {
+    #[doc="Dumps the subtree rooted at this node, for debugging."]
+    fn dump() {
+        self.dump_indent(0u);
+    }
 }
 
 #[cfg(test)]

src/servo/layout/box_builder.rs

@@ -3,27 +3,115 @@
 import dom::base::{nk_div, nk_img, node};
 import dom::rcu::reader_methods;
 import gfx::geom;
-import /*layout::*/base::{bk_block, bk_intrinsic, box, box_kind, btree, ntree};
-import /*layout::*/base::{rd_tree_ops, wr_tree_ops};
-import /*layout::*/style::style::{di_block, di_inline};
+import /*layout::*/base::{bk_block, bk_inline, bk_intrinsic, box, box_kind};
+import /*layout::*/base::{btree, node_methods, ntree, rd_tree_ops};
+import /*layout::*/base::wr_tree_ops;
+import /*layout::*/style::style::{di_block, di_inline, style_methods};
 import util::tree;
 
 export box_builder_methods;
 
+enum ctxt = {
+    // The parent node that we're scanning.
+    parent_node: node,
+    // The parent box that these boxes will be added to.
+    parent_box: @box,
+
+    // The current anonymous box that we're currently appending inline nodes
+    // to.
+    //
+    // See CSS2 9.2.1.1.
+    mut anon_box: option<@box>
+};
+
 fn new_box(n: node, kind: box_kind) -> @box {
     @box({tree: tree::empty(),
           node: n,
           mut bounds: geom::zero_rect_au(),
           kind: kind })
 }
 
-impl box_builder_priv_methods for node {
-    fn construct_boxes() -> @box {
-        let b = new_box(self, self.determine_box_kind());
-        self.aux::<()>({ |a| a.box = some(b); });
-        ret b;
+fn create_context(parent_node: node, parent_box: @box) -> ctxt {
+    ret ctxt({
+        parent_node: parent_node,
+        parent_box: parent_box,
+        mut anon_box: none
+    });
+}
+
+impl methods for ctxt {
+    #[doc="
+        Constructs boxes for the parent's children, when the parent's 'display'
+        attribute is 'block'.
+    "]
+    fn construct_boxes_for_block_children() {
+        for ntree.each_child(self.parent_node) {
+            |kid|
+
+            // Create boxes for the child. Get its primary box.
+            let kid_box = kid.construct_boxes();
+
+            // Determine the child's display.
+            let disp = kid.get_computed_style().display;
+            if disp != di_inline {
+                self.finish_anonymous_box_if_necessary();
+            }
+
+            // Add the child's box to the current enclosing box or the current
+            // anonymous box.
+            alt kid.get_computed_style().display {
+                di_block { btree.add_child(self.parent_box, kid_box); }
+                di_inline {
+                    let anon_box = alt self.anon_box {
+                        none {
+                            let b = new_box(kid, bk_inline);
+                            self.anon_box = some(b);
+                            b
+                        }
+                        some(b) { b }
+                    };
+                    btree.add_child(anon_box, kid_box);
+                }
+            }
+        }
     }
 
+    #[doc="
+        Constructs boxes for the parent's children, when the parent's 'display'
+        attribute is 'inline'.
+    "]
+    fn construct_boxes_for_inline_children() {
+        // TODO
+    }
+
+    #[doc="Constructs boxes for the parent's children."]
+    fn construct_boxes_for_children() {
+        #debug("parent node:");
+        self.parent_node.dump();
+
+        alt self.parent_node.get_computed_style().display {
+            di_block { self.construct_boxes_for_block_children(); }
+            di_inline { self.construct_boxes_for_inline_children(); }
+        }
+
+        self.finish_anonymous_box_if_necessary();
+        assert self.anon_box.is_none();
+    }
+
+    #[doc="
+        Flushes the anonymous box we're creating if it exists. This appends the
+        anonymous box to the block.
+    "]
+    fn finish_anonymous_box_if_necessary() {
+        alt self.anon_box {
+            none { /* Nothing to do. */ }
+            some(b) { btree.add_child(self.parent_box, b); }
+        }
+        self.anon_box = none;
+    }
+}
+
+impl box_builder_priv for node {
     #[doc="
         Determines the kind of box that this node needs. Also, for images,
         computes the intrinsic size.
@@ -37,15 +125,15 @@ impl box_builder_priv_methods for node {
 }
 
 impl box_builder_methods for node {
-    #[doc="Creates boxes for a subtree. This is the entry point."]
-    fn construct_boxes_for_subtree() -> @box {
-        let p_box = self.construct_boxes();
-        for ntree.each_child(self) {
-            |c|
-            let c_box = c.construct_boxes_for_subtree();
-            btree.add_child(p_box, c_box);
+    #[doc="Creates boxes for this node. This is the entry point."]
+    fn construct_boxes() -> @box {
+        let box_kind = self.determine_box_kind();
+        let my_box = new_box(self, box_kind);
+        if box_kind == bk_block {
+            let cx = create_context(self, my_box);
+            cx.construct_boxes_for_children();
         }
-        ret p_box;
+        ret my_box;
     }
 }
 

src/servo/layout/layout.rs

@@ -11,8 +11,8 @@ import gfx::geom;
 import gfx::renderer;
 import dom::base::node;
 import dom::rcu::scope;
+import /*layout::*/base::*;
 import /*layout::*/style::style::style_methods;
-import base::*;
 import box_builder::box_builder_methods;
 import dl = display_list;
 
@@ -29,9 +29,14 @@ fn layout(to_renderer: chan<renderer::msg>) -> chan<msg> {
               ping(ch) { ch.send(content::pong); }
               exit { break; }
               build(node) {
-                #debug("layout: received layout request");
+                #debug("layout: received layout request for:");
+                node.dump();
+
                 node.recompute_style_for_subtree();
-                let this_box = node.construct_boxes_for_subtree();
+
+                let this_box = node.construct_boxes();
+                this_box.dump();
+
                 this_box.reflow(geom::px_to_au(800));
                 let dlist = build_display_list(this_box);
                 to_renderer.send(renderer::render(dlist));

src/servo/layout/style/style.rs

@@ -32,10 +32,17 @@ impl style_priv for node {
     fn recompute_style() {
         let default_style: computed_style =
             default_style_for_node_kind(self.rd { |n| n.kind });
+
+        #debug("recomputing style; parent node:");
+        self.dump();
+
         let the_layout_data = @layout_data({
             mut computed_style: default_style,
             mut box: none
         });
+
+        #debug("layout data: %?", the_layout_data);
+
         self.set_aux(the_layout_data);
     }
 }

test-inline.html

@@ -0,0 +1,6 @@
+<div>
+  <img></img>
+  <div>
+    <img></img><img></img><img></img>
+  </div>
+</div>