Handle row borders in border collapsing logic.

Fixes #11527.

components/layout/table.rs

@@ -311,12 +311,13 @@ impl Flow for TableFlow {
                         &mut self.collapsed_block_direction_border_widths_for_table);
                     previous_collapsed_block_end_borders =
                         PreviousBlockCollapsedBorders::FromPreviousRow(
-                            row.final_collapsed_borders.block_end.clone())
+                            row.final_collapsed_borders.block_end.clone());
                 }
                 first_row = false
-            }
+            };
         }
 
+
         computation.surrounding_size = computation.surrounding_size +
                                        self.total_horizontal_spacing();
 
@@ -425,7 +426,7 @@ impl Flow for TableFlow {
                     collapsed_inline_direction_border_widths_for_table,
                     &mut collapsed_block_direction_border_widths_for_table);
             }
-        })
+        });
     }
 
     fn assign_block_size<'a>(&mut self, _: &'a LayoutContext<'a>) {
@@ -589,7 +590,7 @@ impl ColumnIntrinsicInlineSize {
 ///
 /// TODO(pcwalton): There will probably be some `border-collapse`-related info in here too
 /// eventually.
-#[derive(RustcEncodable, Clone, Copy)]
+#[derive(RustcEncodable, Clone, Copy, Debug)]
 pub struct ColumnComputedInlineSize {
     /// The computed size of this inline column.
     pub size: Au,
@@ -629,27 +630,21 @@ fn perform_border_collapse_for_row(child_table_row: &mut TableRowFlow,
                                    next_block_borders: NextBlockCollapsedBorders,
                                    inline_spacing: &mut Vec<Au>,
                                    block_spacing: &mut Vec<Au>) {
+    let number_of_borders_inline_direction = child_table_row.preliminary_collapsed_borders.inline.len();
     // Compute interior inline borders.
     for (i, this_inline_border) in child_table_row.preliminary_collapsed_borders
                                                   .inline
-                                                  .iter()
+                                                  .iter_mut()
                                                   .enumerate() {
         child_table_row.final_collapsed_borders.inline.push_or_set(i, *this_inline_border);
+        if i == 0 {
+            child_table_row.final_collapsed_borders.inline[i].combine(&table_inline_borders.start);
+        } else if i + 1 == number_of_borders_inline_direction {
+            child_table_row.final_collapsed_borders.inline[i].combine(&table_inline_borders.end);
+        }
 
         let inline_spacing = inline_spacing.get_mut_or_push(i, Au(0));
-        *inline_spacing = cmp::max(*inline_spacing, this_inline_border.width)
-    }
-
-    // Collapse edge interior borders with the table.
-    if let Some(ref mut first_inline_borders) = child_table_row.final_collapsed_borders
-                                                               .inline
-                                                               .get_mut(0) {
-        first_inline_borders.combine(&table_inline_borders.start)
-    }
-    if let Some(ref mut last_inline_borders) = child_table_row.final_collapsed_borders
-                                                              .inline
-                                                              .last_mut() {
-        last_inline_borders.combine(&table_inline_borders.end)
+        *inline_spacing = cmp::max(*inline_spacing, child_table_row.final_collapsed_borders.inline[i].width)
     }
 
     // Compute block-start borders.
@@ -777,6 +772,7 @@ impl TableLikeFlow for BlockFlow {
 }
 
 /// Inline collapsed borders for the table itself.
+#[derive(Debug)]
 struct TableInlineCollapsedBorders {
     /// The table border at the start of the inline direction.
     start: CollapsedBorder,

components/layout/table_row.rs

@@ -245,10 +245,13 @@ impl Flow for TableRowFlow {
                                      .style()
                                      .get_inheritedtable()
                                      .border_collapse == border_collapse::T::collapse;
-        // FIXME(pcwalton): Shouldn't use `CollapsedBorder::new()` here.
-        self.preliminary_collapsed_borders.reset(CollapsedBorder::new());
+        let row_style = &*self.block_flow.fragment.style;
+        self.preliminary_collapsed_borders.reset(
+            CollapsedBorder::inline_start(&row_style,
+                                          CollapsedBorderProvenance::FromTableRow));
 
         {
+            let children_count = self.block_flow.base.children.len();
             let mut iterator = self.block_flow.base.child_iter_mut().enumerate().peekable();
             while let Some((i, kid)) = iterator.next() {
                 assert!(kid.is_table_cell());
@@ -268,6 +271,8 @@ impl Flow for TableRowFlow {
                     // Perform border collapse if necessary.
                     if collapsing_borders {
                         perform_inline_direction_border_collapse_for_row(
+                            row_style,
+                            children_count,
                             i,
                             child_table_cell,
                             &mut iterator,
@@ -829,10 +834,20 @@ pub struct BorderCollapseInfoForChildTableCell<'a> {
 /// table row. This is done eagerly here so that at least the inline inside border collapse
 /// computations can be parallelized across all the rows of the table.
 fn perform_inline_direction_border_collapse_for_row(
+        row_style: &ServoComputedValues,
+        children_count: usize,
         child_index: usize,
         child_table_cell: &mut TableCellFlow,
         iterator: &mut Peekable<Enumerate<MutFlowListIterator>>,
         preliminary_collapsed_borders: &mut CollapsedBordersForRow) {
+    // In the first cell, combine its border with the one coming from the row.
+    if child_index == 0 {
+        let first_inline_border = &mut preliminary_collapsed_borders.inline[0];
+        first_inline_border.combine(
+            &CollapsedBorder::inline_start(&*child_table_cell.block_flow.fragment.style,
+                                           CollapsedBorderProvenance::FromPreviousTableCell));
+    }
+
     let inline_collapsed_border = preliminary_collapsed_borders.inline.push_or_set(
         child_index + 1,
         CollapsedBorder::inline_end(&*child_table_cell.block_flow.fragment.style,
@@ -845,12 +860,25 @@ fn perform_inline_direction_border_collapse_for_row(
                                            CollapsedBorderProvenance::FromNextTableCell))
     };
 
-    let block_start_border =
+    // In the last cell, also take into account the border that may
+    // come from the row.
+    if child_index + 1 == children_count {
+        inline_collapsed_border.combine(
+            &CollapsedBorder::inline_end(&row_style,
+                                         CollapsedBorderProvenance::FromTableRow));
+    }
+
+    let mut block_start_border =
         CollapsedBorder::block_start(&*child_table_cell.block_flow.fragment.style,
                                      CollapsedBorderProvenance::FromNextTableCell);
+    block_start_border.combine(
+        &CollapsedBorder::block_start(row_style, CollapsedBorderProvenance::FromTableRow));
     preliminary_collapsed_borders.block_start.push_or_set(child_index, block_start_border);
-    let block_end_border =
+    let mut block_end_border =
         CollapsedBorder::block_end(&*child_table_cell.block_flow.fragment.style,
-                                   CollapsedBorderProvenance::FromPreviousTableCell);
+                                        CollapsedBorderProvenance::FromPreviousTableCell);
+    block_end_border.combine(
+        &CollapsedBorder::block_end(row_style, CollapsedBorderProvenance::FromTableRow));
+
     preliminary_collapsed_borders.block_end.push_or_set(child_index, block_end_border);
 }

tests/wpt/metadata-css/css21_dev/html4/border-bottom-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-bottom-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-bottom-color-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-bottom-color-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-bottom-width-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-bottom-width-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-conflict-style-101.htm.ini

@@ -1,3 +0,0 @@
-[border-conflict-style-101.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-left-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-left-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-left-color-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-left-color-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-left-width-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-left-width-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-right-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-right-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-right-color-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-right-color-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/border-right-width-applies-to-004.htm.ini

@@ -1,3 +0,0 @@
-[border-right-width-applies-to-004.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/metadata-css/css21_dev/html4/vertical-align-121.htm.ini

@@ -1,3 +0,0 @@
-[vertical-align-121.htm]
-  type: reftest
-  expected: FAIL

tests/wpt/mozilla/meta/MANIFEST.json

@@ -792,6 +792,18 @@
             "url": "/_mozilla/css/border_collapse_missing_cell_a.html"
           }
         ],
+        "css/border_collapse_row_a.html": [
+          {
+            "path": "css/border_collapse_row_a.html",
+            "references": [
+              [
+                "/_mozilla/css/border_collapse_row_ref.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/border_collapse_row_a.html"
+          }
+        ],
         "css/border_collapse_rowgroup_a.html": [
           {
             "path": "css/border_collapse_rowgroup_a.html",
@@ -10102,6 +10114,18 @@
           "url": "/_mozilla/css/border_collapse_missing_cell_a.html"
         }
       ],
+      "css/border_collapse_row_a.html": [
+        {
+          "path": "css/border_collapse_row_a.html",
+          "references": [
+            [
+              "/_mozilla/css/border_collapse_row_ref.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/border_collapse_row_a.html"
+        }
+      ],
       "css/border_collapse_rowgroup_a.html": [
         {
           "path": "css/border_collapse_rowgroup_a.html",

tests/wpt/mozilla/tests/css/border_collapse_row_a.html

@@ -0,0 +1,31 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>row border collapse test</title>
+    <link rel="match" href="border_collapse_row_ref.html">
+    <style>
+      table {
+        border-collapse: collapse;
+      }
+      td {
+        width: 64px;
+        height: 32px;
+      }
+      .tr_with_border {
+        border-top: 2px solid black;
+        border-right: 2px solid black;
+        border-bottom: 2px solid black;
+      }
+    </style>
+  </head>
+  <body>
+    <table>
+      <tr><td></td><td></td></tr>
+      <tr class="tr_with_border"><td></td><td></td></tr>
+      <tr class="tr_with_border"><td></td><td></td></tr>
+      <tr class="tr_with_border"><td></td><td></td></tr>
+      <tr class="tr_with_border"><td></td><td></td></tr>
+    </table>
+  </body>
+</html>

tests/wpt/mozilla/tests/css/border_collapse_row_ref.html

@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <title>row border collapse test - reference</title>
+    <style>
+      table {
+        border-collapse: collapse;
+      }
+      td {
+        width: 64px;
+        height: 32px;
+      }
+      .td_left {
+        border-top: 2px solid black;
+        border-bottom: 2px solid black;
+      }
+      .td_right {
+        border-top: 2px solid black;
+        border-right: 2px solid black;
+        border-bottom: 2px solid black;
+      }
+    </style>
+  </head>
+  <body>
+    <table>
+      <tr><td></td><td></td></tr>
+      <tr><td class="td_left"></td><td class="td_right"</td></tr>
+      <tr><td class="td_left"></td><td class="td_right"</td></tr>
+      <tr><td class="td_left"></td><td class="td_right"</td></tr>
+      <tr><td class="td_left"></td><td class="td_right"</td></tr>
+    </table>
+  </body>
+</html>

tests/wpt/mozilla/tests/css/border_collapse_simple_a.html

@@ -8,6 +8,9 @@
     FIXME(pcwalton): This is currently offset by -2px in block and inline directions because we
     don't correctly handle collapsed borders when calculating `table_border_padding` in
     `table_wrapper.rs`.
+
+    FIXME(gpoesia): This test does not behave exactly like Gecko yet, because cell5's
+    height is currently 2px smaller in Servo.
 -->
 <link rel=match href=border_collapse_simple_ref.html>
 <style>
@@ -19,7 +22,7 @@ html {
 }
 body {
     /* See `FIXME` above. */
-    padding: 2px;
+    padding-top: 2px;
 }
 table {
     border-collapse: collapse;
@@ -28,14 +31,20 @@ table {
 td {
     border: 2px solid black;
     padding: 16px;
-    width: 32px;
+    width: 30px;
     height: 32px;
 }
 td.cell5 {
     border: 30px solid black;
+    width: 32px;
 }
 td.cell6 {
     border: 4px solid black;
+    width: 32px;
+}
+
+#row1 td {
+    height: 32px;
 }
 </style>
 </head>