Move computation of Font::CanShapeWordByWord() to FontFallbackList

Font::CanShapeWordByWord() depends on font face specific data, and
hence, will be invalidated after a font face is loaded.

This patch moves the computation and caching from Font to
FontFallbackList, so that we don't need to invalidate Font for the data
after loading a font face.

This is preparation for crrev.com/c/1952189 that reduces invalidations
after font loading.

Bug: 441925
Change-Id: I605ffbc3981a56f6653cb32d5415b291b03f3b0c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2026594
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Dominik Röttsches <drott@chromium.org>
Cr-Commit-Position: refs/heads/master@{#736639}

third_party/blink/renderer/platform/fonts/font.cc

@@ -48,27 +48,15 @@
 
 namespace blink {
 
-Font::Font() : can_shape_word_by_word_(0), shape_word_by_word_computed_(0) {}
-
-Font::Font(const FontDescription& fd)
-    : font_description_(fd),
-      can_shape_word_by_word_(0),
-      shape_word_by_word_computed_(0) {}
-
-Font::Font(const Font& other)
-    : font_description_(other.font_description_),
-      font_fallback_list_(other.font_fallback_list_),
-      // TODO(yosin): We should have a comment the reason why don't we copy
-      // |m_canShapeWordByWord| and |m_shapeWordByWordComputed| from |other|,
-      // since |operator=()| copies them from |other|.
-      can_shape_word_by_word_(0),
-      shape_word_by_word_computed_(0) {}
+Font::Font() = default;
+
+Font::Font(const FontDescription& fd) : font_description_(fd) {}
+
+Font::Font(const Font& other) = default;
 
 Font& Font::operator=(const Font& other) {
   font_description_ = other.font_description_;
   font_fallback_list_ = other.font_fallback_list_;
-  can_shape_word_by_word_ = other.can_shape_word_by_word_;
-  shape_word_by_word_computed_ = other.shape_word_by_word_computed_;
   return *this;
 }
 
@@ -426,23 +414,8 @@ ShapeCache* Font::GetShapeCache() const {
 }
 
 bool Font::CanShapeWordByWord() const {
-  if (!shape_word_by_word_computed_) {
-    can_shape_word_by_word_ = ComputeCanShapeWordByWord();
-    shape_word_by_word_computed_ = true;
-  }
-  return can_shape_word_by_word_;
-}
-
-bool Font::ComputeCanShapeWordByWord() const {
-  if (!GetFontDescription().GetTypesettingFeatures())
-    return true;
-
-  if (!PrimaryFont())
-    return false;
-
-  const FontPlatformData& platform_data = PrimaryFont()->PlatformData();
-  TypesettingFeatures features = GetFontDescription().GetTypesettingFeatures();
-  return !platform_data.HasSpaceInLigaturesOrKerning(features);
+  return font_fallback_list_ &&
+         font_fallback_list_->CanShapeWordByWord(GetFontDescription());
 }
 
 void Font::ReportNotDefGlyph() const {

third_party/blink/renderer/platform/fonts/font.h

@@ -213,8 +213,8 @@ class PLATFORM_EXPORT Font {
   bool CanShapeWordByWord() const;
 
   void SetCanShapeWordByWordForTesting(bool b) {
-    can_shape_word_by_word_ = b;
-    shape_word_by_word_computed_ = true;
+    if (font_fallback_list_)
+      font_fallback_list_->SetCanShapeWordByWordForTesting(b);
   }
 
   void ReportNotDefGlyph() const;
@@ -224,8 +224,6 @@ class PLATFORM_EXPORT Font {
 
   GlyphData GetEmphasisMarkGlyphData(const AtomicString&) const;
 
-  bool ComputeCanShapeWordByWord() const;
-
  public:
   FontSelector* GetFontSelector() const;
   FontFallbackIterator CreateFontFallbackIterator(
@@ -246,8 +244,6 @@ class PLATFORM_EXPORT Font {
  private:
   FontDescription font_description_;
   mutable scoped_refptr<FontFallbackList> font_fallback_list_;
-  mutable unsigned can_shape_word_by_word_ : 1;
-  mutable unsigned shape_word_by_word_computed_ : 1;
 
   // For m_fontDescription & m_fontFallbackList access.
   friend class CachingWordShaper;

third_party/blink/renderer/platform/fonts/font_fallback_list.cc

@@ -45,7 +45,9 @@ FontFallbackList::FontFallbackList()
       font_selector_version_(0),
       family_index_(0),
       generation_(FontCache::GetFontCache()->Generation()),
-      has_loading_fallback_(false) {}
+      has_loading_fallback_(false),
+      can_shape_word_by_word_(false),
+      can_shape_word_by_word_computed_(false) {}
 
 void FontFallbackList::Invalidate(FontSelector* font_selector) {
   ReleaseFontData();
@@ -53,6 +55,8 @@ void FontFallbackList::Invalidate(FontSelector* font_selector) {
   cached_primary_simple_font_data_ = nullptr;
   family_index_ = 0;
   has_loading_fallback_ = false;
+  can_shape_word_by_word_ = false;
+  can_shape_word_by_word_computed_ = false;
   if (font_selector_ != font_selector)
     font_selector_ = font_selector;
   font_selector_version_ = font_selector_ ? font_selector_->Version() : 0;
@@ -250,6 +254,29 @@ const FontData* FontFallbackList::FontDataAt(
   return result.get();
 }
 
+bool FontFallbackList::ComputeCanShapeWordByWord(
+    const FontDescription& font_description) const {
+  if (!font_description.GetTypesettingFeatures())
+    return true;
+
+  const SimpleFontData* primary_font = PrimarySimpleFontData(font_description);
+  if (!primary_font)
+    return false;
+
+  const FontPlatformData& platform_data = primary_font->PlatformData();
+  TypesettingFeatures features = font_description.GetTypesettingFeatures();
+  return !platform_data.HasSpaceInLigaturesOrKerning(features);
+}
+
+bool FontFallbackList::CanShapeWordByWord(
+    const FontDescription& font_description) const {
+  if (!can_shape_word_by_word_computed_) {
+    can_shape_word_by_word_ = ComputeCanShapeWordByWord(font_description);
+    can_shape_word_by_word_computed_ = true;
+  }
+  return can_shape_word_by_word_;
+}
+
 bool FontFallbackList::IsValid() const {
   if (!font_selector_)
     return font_selector_version_ == 0;

third_party/blink/renderer/platform/fonts/font_fallback_list.h

@@ -71,7 +71,7 @@ class PLATFORM_EXPORT FontFallbackList : public RefCounted<FontFallbackList> {
   }
 
   const SimpleFontData* PrimarySimpleFontData(
-      const FontDescription& font_description) {
+      const FontDescription& font_description) const {
     if (!cached_primary_simple_font_data_) {
       cached_primary_simple_font_data_ =
           DeterminePrimarySimpleFontData(font_description);
@@ -83,6 +83,13 @@ class PLATFORM_EXPORT FontFallbackList : public RefCounted<FontFallbackList> {
 
   FallbackListCompositeKey CompositeKey(const FontDescription&) const;
 
+  bool CanShapeWordByWord(const FontDescription&) const;
+
+  void SetCanShapeWordByWordForTesting(bool b) {
+    can_shape_word_by_word_ = b;
+    can_shape_word_by_word_computed_ = true;
+  }
+
  private:
   FontFallbackList();
 
@@ -92,6 +99,7 @@ class PLATFORM_EXPORT FontFallbackList : public RefCounted<FontFallbackList> {
       const FontDescription&) const;
 
   void ReleaseFontData();
+  bool ComputeCanShapeWordByWord(const FontDescription&) const;
 
   mutable Vector<scoped_refptr<FontData>, 1> font_list_;
   mutable const SimpleFontData* cached_primary_simple_font_data_;
@@ -100,6 +108,8 @@ class PLATFORM_EXPORT FontFallbackList : public RefCounted<FontFallbackList> {
   mutable int family_index_;
   uint16_t generation_;
   mutable bool has_loading_fallback_ : 1;
+  mutable bool can_shape_word_by_word_ : 1;
+  mutable bool can_shape_word_by_word_computed_ : 1;
   mutable base::WeakPtr<ShapeCache> shape_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(FontFallbackList);