Implement CSS font-display

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

Index: third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp
diff --git a/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp b/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp
index 6f68e61ac9619288fe64f8cc9d1f668d0f5db6ad..6e355db1f64efbfa7c00974883ce10c4c03feb6d 100644
--- a/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp
+++ b/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp
@@ -16,9 +16,11 @@
 
 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);
 }
@@ -44,17 +46,17 @@ void RemoteFontFaceSource::pruneTable()
 
 bool RemoteFontFaceSource::isLoading() const
 {
-    return !m_font->stillNeedsLoad() && !m_font->isLoaded();
+    return m_period != FailurePeriod && !m_font->stillNeedsLoad() && !m_font->isLoaded();
 }
 
 bool RemoteFontFaceSource::isLoaded() const
 {
-    return m_font->isLoaded();
+    return m_period == FailurePeriod || m_font->isLoaded();

[Yoav Weiss, 2015/11/02 08:57:28]

So failure is defined as loaded? Can you add a link to the corresponding spec
definition (if there is one)?

[Kunihiko Sakamoto, 2015/11/04 02:32:51]

This is to make the RemoteFontFaceSource behave as if the load failed.

https://tabatkins.github.io/specs/css-font-display/#font-failure-period
As side effects, this turns the FontFace status [1] to "error" and fires
"loadingerror" event [2] on document.fonts. I'm not sure this is correct, so
filed a spec bug. https://github.com/tabatkins/specs/issues/48

[1] https://drafts.csswg.org/css-font-loading/#dom-fontface-status
[2] https://drafts.csswg.org/css-font-loading/#dom-fontfaceset-loadingerror

[Kunihiko Sakamoto, 2015/11/17 05:47:43]

Changed it not to treat failure period as loaded, as per the spec bug
discussion. https://github.com/tabatkins/specs/issues/48

 }
 
 bool RemoteFontFaceSource::isValid() const
 {
-    return !m_font->errorOccurred();
+    return m_period != FailurePeriod && !m_font->errorOccurred();
 }
 
 void RemoteFontFaceSource::didStartFontLoad(FontResource*)
@@ -80,17 +82,50 @@ void RemoteFontFaceSource::fontLoaded(FontResource*)
     }
 }
 
-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->fontDataInvalidated(this);
     }
 
     m_histograms.recordFallbackTime(m_font.get());
 }
 
+void RemoteFontFaceSource::switchToFailurePeriod()
+{
+    if (m_period == BlockPeriod)
+        switchToSwapPeriod();
+    ASSERT(m_period == SwapPeriod);
+    m_period = FailurePeriod;
+
+    pruneTable();
+    if (m_face) {
+        m_fontLoader->fontFaceInvalidated();
+        m_face->fontLoaded(this);
+    }
+}
+
 PassRefPtr<SimpleFontData> RemoteFontFaceSource::createFontData(const FontDescription& fontDescription)
 {
     if (!isLoaded())
@@ -117,7 +152,7 @@ PassRefPtr<SimpleFontData> RemoteFontFaceSource::createLoadingFallbackFontData(c
         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);
 }