Add m_isGlyphLookupMode to UniscribeHelper class and set it to true when fill...

third_party/WebKit/WebCore/platform/graphics/chromium/UniscribeHelper.cpp

 // Copyright (c) 2006-2008 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 "config.h"
 #include "UniscribeHelper.h"
 
 #include <windows.h>
 
 #include "FontUtilsChromiumWin.h"
@@ skipping 68 matching lines @@
     , m_isRtl(isRtl)
     , m_hfont(hfont)
     , m_scriptCache(scriptCache)
     , m_fontProperties(fontProperties)
     , m_directionalOverride(false)
     , m_inhibitLigate(false)
     , m_letterSpacing(0)
     , m_spaceWidth(0)
     , m_wordSpacing(0)
     , m_ascent(0)
+    , m_disableFontFallback(false)
+
 {
     m_logfont.lfFaceName[0] = 0;
 }
 
 UniscribeHelper::~UniscribeHelper()
 {
 }
 
 void UniscribeHelper::InitWithOptionalLengthProtection(bool lengthProtection)
 {
@@ skipping 402 matching lines @@
                             SCRIPT_ITEM& run,
                             Shaping& shaping)
 {
     HFONT hfont = m_hfont;
     SCRIPT_CACHE* scriptCache = m_scriptCache;
     SCRIPT_FONTPROPERTIES* fontProperties = m_fontProperties;
     int ascent = m_ascent;
     HDC tempDC = NULL;
     HGDIOBJ oldFont = 0;
     HRESULT hr;
-    bool lastFallbackTried = false;
+    // When used to fill up glyph pages for simple scripts in non-BMP,
+    // we don't want any font fallback in this class. The simple script
+    // font path can take care of font fallback.
+    bool lastFallbackTried = m_disableFontFallback;
     bool result;
 
     int generatedGlyphs = 0;
 
     // In case HFONT passed in ctor cannot render this run, we have to scan
     // other fonts from the beginning of the font list.
     ResetFontIndex();
 
     // Compute shapes.
     while (true) {
@@ skipping 43 matching lines @@
         }
 
         // The current font can't render this run. clear DC and try
         // next font.
         if (tempDC) {
             SelectObject(tempDC, oldFont);
             ReleaseDC(NULL, tempDC);
             tempDC = NULL;
         }
 
-        if (NextWinFontData(&hfont, &scriptCache, &fontProperties, &ascent)) {
+        if (!m_disableFontFallback &&
+            NextWinFontData(&hfont, &scriptCache, &fontProperties, &ascent)) {
             // The primary font does not support this run. Try next font.
             // In case of web page rendering, they come from fonts specified in
             // CSS stylesheets.
             continue;
         } else if (!lastFallbackTried) {
             lastFallbackTried = true;
 
             // Generate a last fallback font based on the script of
             // a character to draw while inheriting size and styles
             // from the primary font
@@ skipping 95 matching lines @@
             numGlyphs = itemLength * 3 / 2 + 16;
         }
 
         // Convert a string to a glyph string trying the primary font, fonts in
         // the fallback list and then script-specific last resort font.
         Shaping& shaping = m_shapes[i];
         if (!Shape(&m_input[startItem], itemLength, numGlyphs, m_runs[i],
                    shaping))
             continue;
 
+        // At the moment, the only time m_disableFontFallback is set is
+        // when we look up glyph indices for non-BMP code ranges. So,
+        // we can skip the glyph placement. When that becomes not the case
+        // any more, we have to add a new flag to control glyph placement.
+        if (m_disableFontFallback)
+          continue;
+
         // Compute placements. Note that offsets is documented incorrectly
         // and is actually an array.
 
         // DC that we lazily create if Uniscribe commands us to.
         // (this does not happen often because scriptCache is already
         //  updated when calling ScriptShape).
         HDC tempDC = NULL;
         HGDIOBJ oldFont = NULL;
         HRESULT hr;
         while (true) {
@@ skipping 178 matching lines @@
     // justification array contains both the advance and the extra space
     // added for justification, so is the width we want.
     int justification = 0;
     for (size_t i = 0; i < shaping.m_justify.size(); i++)
         justification += shaping.m_justify[i];
 
     return shaping.m_prePadding + justification;
 }
 
 }  // namespace WebCore