First step of PaintInvalidator implementation

third_party/WebKit/Source/core/paint/TablePaintInvalidator.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/paint/TablePaintInvalidator.h"
+
+#include "core/layout/LayoutTable.h"
+#include "core/layout/LayoutTableCell.h"
+#include "core/layout/LayoutTableCol.h"
+#include "core/layout/LayoutTableRow.h"
+#include "core/layout/LayoutTableSection.h"
+#include "core/paint/BoxPaintInvalidator.h"
+#include "core/paint/PaintInvalidator.h"
+
+namespace blink {
+
+PaintInvalidationReason TablePaintInvalidator::invalidatePaintIfNeeded()
+{
+    PaintInvalidationReason reason = BoxPaintInvalidator(m_table, m_context).invalidatePaintIfNeeded();
+
+    // Table cells paint background from the containing column group, column, section and row.
+    // If background of any of them changed, we need to invalidate all affected cells.
+    // Here use shouldDoFullPaintInvalidation() as a broader condition of background change.
+
+    // If any col changed background, we'll check all cells for background changes.
+    bool hasColChangedBackground = false;
+    for (LayoutTableCol* col = m_table.firstColumn(); col; col = col->nextColumn()) {
+        if (col->backgroundChangedSinceLastPaintInvalidation()) {
+            hasColChangedBackground = true;
+            break;
+        }
+    }
+    for (LayoutObject* child = m_table.firstChild(); child; child = child->nextSibling()) {
+        if (!child->isTableSection())
+            continue;
+        LayoutTableSection* section = toLayoutTableSection(child);
+        if (!hasColChangedBackground && !section->shouldCheckForPaintInvalidationRegardlessOfPaintInvalidationState())
+            continue;
+        for (LayoutTableRow* row = section->firstRow(); row; row = row->nextRow()) {
+            if (!hasColChangedBackground && !section->backgroundChangedSinceLastPaintInvalidation() && !row->backgroundChangedSinceLastPaintInvalidation())
+                continue;
+            for (LayoutTableCell* cell = row->firstCell(); cell; cell = cell->nextCell()) {
+                bool invalidated = false;
+                // Table cells paint container's background on the container's backing instead of its own (if any),
+                // so we must invalidate it by the containers.
+                if (section->backgroundChangedSinceLastPaintInvalidation()) {
+                    section->slowSetPaintingLayerNeedsRepaintAndInvalidateDisplayItemClient(*cell, PaintInvalidationStyleChange);
+                    invalidated = true;
+                } else if (hasColChangedBackground) {
+                    LayoutTable::ColAndColGroup colAndColGroup = m_table.colElementAtAbsoluteColumn(cell->absoluteColumnIndex());
+                    LayoutTableCol* column = colAndColGroup.col;
+                    LayoutTableCol* columnGroup = colAndColGroup.colgroup;
+                    if ((columnGroup && columnGroup->backgroundChangedSinceLastPaintInvalidation())
+                        || (column && column->backgroundChangedSinceLastPaintInvalidation())) {
+                        section->slowSetPaintingLayerNeedsRepaintAndInvalidateDisplayItemClient(*cell, PaintInvalidationStyleChange);
+                        invalidated = true;
+                    }
+                }
+                if ((!invalidated || row->hasSelfPaintingLayer()) && row->backgroundChangedSinceLastPaintInvalidation())
+                    row->slowSetPaintingLayerNeedsRepaintAndInvalidateDisplayItemClient(*cell, PaintInvalidationStyleChange);
+            }
+        }
+    }
+
+    return reason;
+}
+
+} // namespace blink