Change Font::offsetForPositionForComplexText to use CachingWordShapeIterator

Source/platform/fonts/shaping/HarfBuzzShaper.cpp

 /*
  * Copyright (c) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 BlackBerry Limited. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 21 matching lines @@
 #include "config.h"
 #include "platform/fonts/shaping/HarfBuzzShaper.h"
 
 #include "hb.h"
 #include "platform/LayoutUnit.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/fonts/Character.h"
 #include "platform/fonts/Font.h"
 #include "platform/fonts/GlyphBuffer.h"
 #include "platform/fonts/UTF16TextIterator.h"
+#include "platform/fonts/shaping/CachingWordShapeIterator.h"
 #include "platform/fonts/shaping/HarfBuzzFace.h"
 #include "platform/text/TextBreakIterator.h"
 #include "wtf/Compiler.h"
 #include "wtf/MathExtras.h"
 #include "wtf/text/Unicode.h"
 
 #include <list>
 #include <map>
 #include <string>
 #include <unicode/normlzr.h>
@@ skipping 382 matching lines @@
         toX = direction == RTL ? 0 : totalWidth;
 
     // None of our runs is part of the selection, possibly invalid arguments.
     if (!foundToX && !foundFromX)
         fromX = toX = 0;
     if (fromX < toX)
         return FloatRect(point.x() + fromX, point.y(), toX - fromX, height);
     return FloatRect(point.x() + toX, point.y(), fromX - toX, height);
 }
 
+int ShapeResult::offsetForPosition(CachingWordShapeIterator& iterator,
+    const TextRun& run, float targetX)
+{
+    RefPtr<ShapeResult> wordResult;
+    unsigned totalOffset;
+    if (run.rtl()) {
+        totalOffset = run.length();
+        while (iterator.next(&wordResult)) {
+            if (!wordResult)
+                continue;
+            totalOffset -= wordResult->numCharacters();
+            if (targetX >= 0 && targetX <= wordResult->width()) {
+                int offsetForWord = wordResult->offsetForPosition(targetX);
+                return totalOffset + offsetForWord;
+            }
+            targetX -= wordResult->width();
+        }
+    } else {
+        totalOffset = 0;
+        while (iterator.next(&wordResult)) {
+            if (!wordResult)
+                continue;
+            int offsetForWord = wordResult->offsetForPosition(targetX);
+            ASSERT(offsetForWord >= 0);
+            totalOffset += offsetForWord;
+            if (targetX >= 0 && targetX <= wordResult->width())
+                return totalOffset;
+            targetX -= wordResult->width();
+        }
+    }
+    return totalOffset;
+}
+
 int ShapeResult::offsetForPosition(float targetX)
 {
     int charactersSoFar = 0;
     float currentX = 0;
 
     if (m_direction == RTL) {
         charactersSoFar = m_numCharacters;
         for (unsigned i = 0; i < m_runs.size(); ++i) {
             if (!m_runs[i])
                 continue;
@@ skipping 699 matching lines @@
             return spacing;
     }
 
     // Don't need to check m_textRun.allowsTrailingExpansion() since it's covered by !m_expansionOpportunityCount above
     spacing += nextExpansionPerOpportunity();
     m_isAfterExpansion = true;
     return spacing;
 }
 
 } // namespace blink