Implement CSS font-display

third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp

 // Copyright 2014 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 "core/css/RemoteFontFaceSource.h"
 
 #include "core/css/CSSCustomFontData.h"
 #include "core/css/CSSFontFace.h"
 #include "core/css/FontLoader.h"
 #include "platform/fonts/FontCache.h"
 #include "platform/fonts/FontDescription.h"
 #include "platform/fonts/SimpleFontData.h"
 #include "public/platform/Platform.h"
 #include "wtf/CurrentTime.h"
 
 namespace blink {
 
-RemoteFontFaceSource::RemoteFontFaceSource(FontResource* font, PassRefPtrWillBeRawPtr<FontLoader> fontLoader)
+RemoteFontFaceSource::RemoteFontFaceSource(FontResource* font, PassRefPtrWillBeRawPtr<FontLoader> fontLoader, FontDisplay display)
     : m_font(font)
     , m_fontLoader(fontLoader)
+    , m_display(display)
+    , m_period(display == FontDisplaySwap ? SwapPeriod : BlockPeriod)
 {
     m_font->addClient(this);
 }
 
 RemoteFontFaceSource::~RemoteFontFaceSource()
 {
     m_font->removeClient(this);
     pruneTable();
 }
 
@@ skipping 41 matching lines @@
     if (m_font->status() == Resource::DecodeError)
         m_fontLoader->didFailToDecode(m_font.get());
 
     pruneTable();
     if (m_face) {
         m_fontLoader->fontFaceInvalidated();
         m_face->fontLoaded(this);
     }
 }
 
-void RemoteFontFaceSource::fontLoadWaitLimitExceeded(FontResource*)
+void RemoteFontFaceSource::fontLoadShortLimitExceeded(FontResource*)
 {
+    if (m_display == FontDisplayFallback)
+        switchToSwapPeriod();
+    else if (m_display == FontDisplayOptional)
+        switchToFailurePeriod();
+}
+
+void RemoteFontFaceSource::fontLoadLongLimitExceeded(FontResource*)
+{
+    if (m_display == FontDisplayAuto || m_display == FontDisplayBlock)
+        switchToSwapPeriod();
+    else if (m_display == FontDisplayFallback)
+        switchToFailurePeriod();
+}
+
+void RemoteFontFaceSource::switchToSwapPeriod()
+{
+    ASSERT(m_period == BlockPeriod);
+    m_period = SwapPeriod;
+
     pruneTable();
     if (m_face) {
         m_fontLoader->fontFaceInvalidated();
-        m_face->fontLoadWaitLimitExceeded(this);
+        m_face->didBecomeVisibleFallback(this);
     }
 
     m_histograms.recordFallbackTime(m_font.get());
 }
 
+void RemoteFontFaceSource::switchToFailurePeriod()
+{
+    if (m_period == BlockPeriod)
+        switchToSwapPeriod();
+    ASSERT(m_period == SwapPeriod);
+    m_period = FailurePeriod;
+}
+
 PassRefPtr<SimpleFontData> RemoteFontFaceSource::createFontData(const FontDescription& fontDescription)
 {
     if (!isLoaded())
         return createLoadingFallbackFontData(fontDescription);
 
-    // Create new FontPlatformData from our CGFontRef, point size and ATSFontRef.
-    if (!m_font->ensureCustomFontData())
+    if (!m_font->ensureCustomFontData() || m_period == FailurePeriod)
         return nullptr;
 
     m_histograms.recordFallbackTime(m_font.get());
 
     return SimpleFontData::create(
         m_font->platformDataFromCustomData(fontDescription.effectiveFontSize(),
             fontDescription.isSyntheticBold(), fontDescription.isSyntheticItalic(),
             fontDescription.orientation()), CustomFontData::create());
 }
 
 PassRefPtr<SimpleFontData> RemoteFontFaceSource::createLoadingFallbackFontData(const FontDescription& fontDescription)
 {
     // This temporary font is not retained and should not be returned.
     FontCachePurgePreventer fontCachePurgePreventer;
     SimpleFontData* temporaryFont = FontCache::fontCache()->getNonRetainedLastResortFallbackFont(fontDescription);
     if (!temporaryFont) {
         ASSERT_NOT_REACHED();
         return nullptr;
     }
-    RefPtr<CSSCustomFontData> cssFontData = CSSCustomFontData::create(this, m_font->exceedsFontLoadWaitLimit() ? CSSCustomFontData::VisibleFallback : CSSCustomFontData::InvisibleFallback);
+    RefPtr<CSSCustomFontData> cssFontData = CSSCustomFontData::create(this, m_period == BlockPeriod ? CSSCustomFontData::InvisibleFallback : CSSCustomFontData::VisibleFallback);
     return SimpleFontData::create(temporaryFont->platformData(), cssFontData);
 }
 
 void RemoteFontFaceSource::beginLoadIfNeeded()
 {
     if (m_font->stillNeedsLoad())
         m_fontLoader->addFontToBeginLoading(m_font.get());
 
     if (m_face)
         m_face->didBeginLoad();
@@ skipping 56 matching lines @@
     if (size < 50 * 1024)
         return "WebFont.DownloadTime.1.10KBTo50KB";
     if (size < 100 * 1024)
         return "WebFont.DownloadTime.2.50KBTo100KB";
     if (size < 1024 * 1024)
         return "WebFont.DownloadTime.3.100KBTo1MB";
     return "WebFont.DownloadTime.4.Over1MB";
 }
 
 } // namespace blink