Optimize Complex Text Shaping and Caching

Source/platform/fonts/shaping/CachingWordShaper.cpp

Index: Source/platform/fonts/shaping/CachingWordShaper.cpp
diff --git a/Source/platform/fonts/shaping/CachingWordShaper.cpp b/Source/platform/fonts/shaping/CachingWordShaper.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..30f11b8cb1b9d754fd6236d026425d1cdf8ebafb
--- /dev/null
+++ b/Source/platform/fonts/shaping/CachingWordShaper.cpp
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2015 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY GOOGLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "platform/fonts/shaping/CachingWordShaper.h"
+
+#include "platform/fonts/SimpleFontData.h"
+#include "platform/fonts/shaping/CachingWordShapeIterator.h"
+#include "platform/fonts/shaping/HarfBuzzShaper.h"
+#include "platform/fonts/shaping/ShapeCache.h"
+#include "wtf/unicode/CharacterNames.h"
+
+namespace blink {
+
+CachingWordShaper::CachingWordShaper()
+{
+    m_shapeCache = new ShapeCache();
+}
+
+CachingWordShaper::~CachingWordShaper()
+{
+    delete m_shapeCache;
+}
+
+void CachingWordShaper::clear()
+{
+    if (m_shapeCache)
+        m_shapeCache->clear();
+}
+
+float CachingWordShaper::width(const Font* font, const TextRun& run,
+    HashSet<const SimpleFontData*>* fallbackFonts,
+    FloatRect* glyphBounds)
+{
+    float width = 0;
+    RefPtr<ShapeResult> wordResult;
+    CachingWordShapeIterator iterator(m_shapeCache, run, font, fallbackFonts);
+    while (iterator.next(&wordResult)) {
+        if (wordResult) {
+            width += wordResult->width();
+            if (glyphBounds)
+                glyphBounds->unite(wordResult->bounds());
+        }
+    }
+
+    return width;
+}
+
+float CachingWordShaper::fillGlyphBuffer(const Font* font, const TextRun& run,
+    HashSet<const SimpleFontData*>* fallbackFonts,
+    GlyphBuffer* glyphBuffer, unsigned from, unsigned to)
+{
+    CachingWordShapeIterator iterator(m_shapeCache, run, font, fallbackFonts);
+    RefPtr<ShapeResult> wordResult;
+    Vector<RefPtr<ShapeResult>> results;
+    unsigned totalChars = 0;
+    float width = 0;
+    while (iterator.next(&wordResult)) {
+        if (wordResult) {
+            results.append(wordResult);
+            totalChars += wordResult->numCharacters();
+            width += wordResult->width();
+        }
+    }
+
+    float advance = 0;
+    if (run.rtl()) {
+        unsigned wordOffset = totalChars;
+        for (unsigned i = 0; i < results.size(); i++) {
+            unsigned resolvedIndex = results.size() - 1 - i;
+            RefPtr<ShapeResult>& wordResult = results[resolvedIndex];
+            advance += wordResult->fillGlyphBuffer(glyphBuffer, advance,
+                from, to, wordOffset - wordResult->numCharacters());
+            wordOffset -= wordResult->numCharacters();
+        }
+    } else {
+        unsigned wordOffset = 0;
+        for (unsigned i = 0; i < results.size(); i++) {
+            RefPtr<ShapeResult>& wordResult = results[i];
+            advance += wordResult->fillGlyphBuffer(glyphBuffer, advance,
+                from, to, wordOffset);
+            wordOffset += wordResult->numCharacters();
+        }
+    }
+
+    return width;
+}
+
+}; // namespace blink