SkTextBlob: Begin implementing Extended TextBlob API

src/core/SkTextBlob.cpp

Index: src/core/SkTextBlob.cpp
diff --git a/src/core/SkTextBlob.cpp b/src/core/SkTextBlob.cpp
index 1cbb2b6d6dabc9750c620b98cd1c8ec64c5adc84..7397fbeb62209395fa38f5977826f40744cee3c2 100644
--- a/src/core/SkTextBlob.cpp
+++ b/src/core/SkTextBlob.cpp
@@ -110,11 +110,12 @@ SkDEBUGCODE(static const unsigned kRunRecordMagic = 0xb10bcafe;)
 
 class SkTextBlob::RunRecord {
 public:
-    RunRecord(uint32_t count, const SkPoint& offset, const SkPaint& font, GlyphPositioning pos)
+    RunRecord(uint32_t count, const SkPoint& offset, const SkPaint& font, GlyphPositioning pos, bool extended)
         : fFont(font)
         , fCount(count)
         , fOffset(offset)
-        , fPositioning(pos) {
+        , fPositioning(pos)
+        , fExtended(extended) {
         SkDEBUGCODE(fMagic = kRunRecordMagic);
     }
 
@@ -135,6 +136,7 @@ public:
     }
 
     uint16_t* glyphBuffer() const {
+        static_assert(SkIsAlignPtr(sizeof(RunRecord)), "");
         // Glyph are stored immediately following the record.

[f(malita), 2016/06/27 20:21:55]

nit: "Glyphs", while we're here

[hal.canary, 2016/06/28 15:39:13]

Done.

         return reinterpret_cast<uint16_t*>(const_cast<RunRecord*>(this) + 1);
     }
@@ -145,11 +147,42 @@ public:
                                            SkAlign4(fCount * sizeof(uint16_t)));
     }
 
-    static size_t StorageSize(int glyphCount, SkTextBlob::GlyphPositioning positioning) {
+    uint32_t textSize() const {

[f(malita), 2016/06/27 20:21:55]

maybe uint32_t* textSizePtr() for reuse?

[hal.canary, 2016/06/28 15:39:12]

Done.

+        // textSize follows the position buffer.
+        if (!fExtended) { return 0; }
+        return *(uint32_t*)(&this->posBuffer()[ScalarsPerGlyph(fPositioning) * fCount]);

[f(malita), 2016/06/27 20:21:55]

nit: reinterpret_cast instead of old-style cast?

[hal.canary, 2016/06/28 15:39:12]

Done.

+    }
+
+    void setTextSize(uint32_t size) {

[f(malita), 2016/06/27 20:21:55]

I think we can get rid of the setter, see suggestion below.

[hal.canary, 2016/06/28 15:39:12]

Done.

+        SkASSERT(fExtended);
+        *(uint32_t*)(&this->posBuffer()[ScalarsPerGlyph(fPositioning) * fCount]) = size;

[f(malita), 2016/06/27 20:21:55]

nit: reinterpret_cast

[hal.canary, 2016/06/28 15:39:12]

Done.

+
+    }
+    uint32_t* clusterBuffer() const {
+        // clusters follow the textSize.
+        if (!fExtended) { return nullptr; }
+        return (uint32_t*)(&this->posBuffer()[ScalarsPerGlyph(fPositioning) * fCount]) + 1;

[f(malita), 2016/06/27 20:21:55]

return textSizePtr() + 1 ?

[hal.canary, 2016/06/28 15:39:12]

Done.

+    }
+
+    char* textBuffer() const {
+        if (!fExtended) { return nullptr; }
+        return (char*)((uint32_t*)(&this->posBuffer()[ScalarsPerGlyph(fPositioning) * fCount]) + 1 + fCount);

[f(malita), 2016/06/27 20:21:55]

return reinterpret_cast<char*>(clusterBuffer() + fCount) ?

[hal.canary, 2016/06/28 15:39:13]

Done.

+    }
+
+    static size_t StorageSize(int glyphCount, int textSize, SkTextBlob::GlyphPositioning positioning) {
         // RunRecord object + (aligned) glyph buffer + position buffer
-        return SkAlignPtr(sizeof(SkTextBlob::RunRecord)
-                        + SkAlign4(glyphCount* sizeof(uint16_t))
-                        + glyphCount * sizeof(SkScalar) * ScalarsPerGlyph(positioning));
+        if (0 == textSize) {
+            return SkAlignPtr(sizeof(SkTextBlob::RunRecord)
+                              + SkAlign4(glyphCount* sizeof(uint16_t))
+                              + glyphCount * sizeof(SkScalar) * ScalarsPerGlyph(positioning));
+        } else {
+            return SkAlignPtr(sizeof(SkTextBlob::RunRecord)
+                              + SkAlign4(glyphCount* sizeof(uint16_t))
+                              + glyphCount * sizeof(SkScalar) * ScalarsPerGlyph(positioning)
+                              + sizeof(uint32_t)
+                              + sizeof(uint32_t) * glyphCount
+                              + textSize);
+        }

[f(malita), 2016/06/27 20:21:55]

nit: maybe somewhat DRY-er

  size_t size = ...;
  if (textSize) {
      size += ...;
  }
  return SkAlignPtr(size);

[hal.canary, 2016/06/28 15:39:12]

Done.

     }
 
     static const RunRecord* First(const SkTextBlob* blob) {
@@ -158,13 +191,15 @@ public:
     }
 
     static const RunRecord* Next(const RunRecord* run) {
-        return reinterpret_cast<const RunRecord*>(reinterpret_cast<const uint8_t*>(run)
-            + StorageSize(run->glyphCount(), run->positioning()));
+        return reinterpret_cast<const RunRecord*>(
+                reinterpret_cast<const uint8_t*>(run)
+                + StorageSize(run->glyphCount(), run->textSize(), run->positioning()));
     }
 
     void validate(const uint8_t* storageTop) const {
         SkASSERT(kRunRecordMagic == fMagic);
         SkASSERT((uint8_t*)Next(this) <= storageTop);
+
         SkASSERT(glyphBuffer() + fCount <= (uint16_t*)posBuffer());
         SkASSERT(posBuffer() + fCount * ScalarsPerGlyph(fPositioning) <= (SkScalar*)Next(this));

[f(malita), 2016/06/27 20:21:55]

We should also add asserts for the new buffers.

[hal.canary, 2016/06/28 15:39:12]

Done.

     }
@@ -189,6 +224,7 @@ private:
     uint32_t         fCount;
     SkPoint          fOffset;
     GlyphPositioning fPositioning;
+    bool             fExtended;
 
     SkDEBUGCODE(unsigned fMagic;)
 };

[f(malita), 2016/06/27 20:21:55]

Similar to RunFont above:

namespace {

struct RunRecordStorageEquivalent {
    RunFont  fFont;
    SkPoint  fOffset;
    uint32_t fCount, fFlags;
};

static_assert(sizeof(RunRecord) == sizeof(RunRecordStorageEquivalent),
"runrecord_should_stay_packed");
}

?

[hal.canary, 2016/06/28 15:39:12]

Done.

@@ -206,6 +242,11 @@ SkTextBlob::SkTextBlob(int runCount, const SkRect& bounds)
     : fRunCount(runCount)
     , fBounds(bounds)
     , fUniqueID(next_id()) {
+    #ifdef SK_DEBUG
+        static_assert(sizeof(SkTextBlob::RunRecord) == SkAlignPtr(sizeof(void*) + 29 + 4), "");
+    #else
+        static_assert(sizeof(SkTextBlob::RunRecord) == SkAlignPtr(sizeof(void*) + 29), "");
+    #endif

[f(malita), 2016/06/27 20:21:55]

Not needed with RunRecordStorageEquivalent above.

[hal.canary, 2016/06/28 15:39:12]

Done.

 }
 
 SkTextBlob::~SkTextBlob() {
@@ -218,6 +259,17 @@ SkTextBlob::~SkTextBlob() {
     }
 }
 
+namespace {
+union PositioningAndExtended {
+    int32_t intValue;
+    struct {
+        SkTextBlob::GlyphPositioning positioning;
+        bool extended;
+        uint16_t padding;
+    };
+};
+} // namespace
+
 void SkTextBlob::flatten(SkWriteBuffer& buffer) const {
     int runCount = fRunCount;
 
@@ -230,7 +282,15 @@ void SkTextBlob::flatten(SkWriteBuffer& buffer) const {
         SkASSERT(it.glyphCount() > 0);
 
         buffer.write32(it.glyphCount());
-        buffer.write32(it.positioning());
+        PositioningAndExtended pe;
+        pe.intValue = 0;
+        pe.positioning = it.positioning();
+        SkASSERT((int32_t)it.positioning() == pe.intValue);  // backwards compat.
+        pe.extended = it.isExtended();
+        buffer.write32(pe.intValue);
+        if (pe.extended) {
+            buffer.write32(it.textSize());
+        }
         buffer.writePoint(it.offset());
         // This should go away when switching to SkFont
         it.applyFontToPaint(&runPaint);
@@ -239,6 +299,10 @@ void SkTextBlob::flatten(SkWriteBuffer& buffer) const {
         buffer.writeByteArray(it.glyphs(), it.glyphCount() * sizeof(uint16_t));
         buffer.writeByteArray(it.pos(),
             it.glyphCount() * sizeof(SkScalar) * ScalarsPerGlyph(it.positioning()));
+        if (pe.extended) {
+            buffer.writeByteArray(it.clusterBuffer(), sizeof(uint32_t) * it.glyphCount());
+            buffer.writeByteArray(it.textBuffer(), it.textSize());
+        }
 
         it.next();
         SkDEBUGCODE(runCount--);
@@ -258,10 +322,14 @@ const SkTextBlob* SkTextBlob::CreateFromBuffer(SkReadBuffer& reader) {
     SkTextBlobBuilder blobBuilder;
     for (int i = 0; i < runCount; ++i) {
         int glyphCount = reader.read32();
-        GlyphPositioning pos = static_cast<GlyphPositioning>(reader.read32());
+
+        PositioningAndExtended pe;
+        pe.intValue = reader.read32();
+        GlyphPositioning pos = pe.positioning;
         if (glyphCount <= 0 || pos > kFull_Positioning) {
             return nullptr;
         }
+        uint32_t textSize = pe.extended ? (uint32_t)reader.read32() : 0;
 
         SkPoint offset;
         reader.readPoint(&offset);
@@ -271,13 +339,15 @@ const SkTextBlob* SkTextBlob::CreateFromBuffer(SkReadBuffer& reader) {
         const SkTextBlobBuilder::RunBuffer* buf = nullptr;
         switch (pos) {
         case kDefault_Positioning:
-            buf = &blobBuilder.allocRun(font, glyphCount, offset.x(), offset.y(), &bounds);
+            buf = &blobBuilder.allocRunText(font, glyphCount, offset.x(), offset.y(),
+                                            textSize, SkString(), &bounds);
             break;
         case kHorizontal_Positioning:
-            buf = &blobBuilder.allocRunPosH(font, glyphCount, offset.y(), &bounds);
+            buf = &blobBuilder.allocRunTextPosH(font, glyphCount, offset.y(),
+                                                textSize, SkString(), &bounds);
             break;
         case kFull_Positioning:
-            buf = &blobBuilder.allocRunPos(font, glyphCount, &bounds);
+            buf = &blobBuilder.allocRunTextPos(font, glyphCount, textSize, SkString(), &bounds);
             break;
         default:
             return nullptr;
@@ -288,6 +358,13 @@ const SkTextBlob* SkTextBlob::CreateFromBuffer(SkReadBuffer& reader) {
                                   glyphCount * sizeof(SkScalar) * ScalarsPerGlyph(pos))) {
             return nullptr;
         }
+
+        if (pe.extended) {
+            if (!reader.readByteArray(buf->clusters, glyphCount * sizeof(uint32_t))  ||
+                !reader.readByteArray(buf->utf8text, textSize)) {
+                return nullptr;
+            }
+        }
     }
 
     return blobBuilder.build();
@@ -350,6 +427,24 @@ void SkTextBlobRunIterator::applyFontToPaint(SkPaint* paint) const {
     fCurrentRun->font().applyToPaint(paint);
 }
 
+bool SkTextBlobRunIterator::isExtended() const {
+    SkASSERT(!this->done());
+    return fCurrentRun->textSize() > 0;
+}
+uint32_t* SkTextBlobRunIterator::clusterBuffer() const {
+    SkASSERT(!this->done());
+    return fCurrentRun->clusterBuffer();
+}
+uint32_t SkTextBlobRunIterator::textSize() const {
+    SkASSERT(!this->done());
+    return fCurrentRun->textSize();
+}
+char* SkTextBlobRunIterator::textBuffer() const {
+    SkASSERT(!this->done());
+    return fCurrentRun->textBuffer();
+}
+
+
 bool SkTextBlobRunIterator::isLCD() const {
     return SkToBool(fCurrentRun->font().flags() & SkPaint::kLCDRenderText_Flag);
 }
@@ -513,6 +608,10 @@ bool SkTextBlobBuilder::mergeRun(const SkPaint &font, SkTextBlob::GlyphPositioni
                                                                           fLastRun);
     SkASSERT(run->glyphCount() > 0);
 
+    if (run->textSize() != 0) {
+        return false;
+    }
+
     if (run->positioning() != positioning
         || run->font() != font
         || (run->glyphCount() + count < run->glyphCount())) {
@@ -529,8 +628,8 @@ bool SkTextBlobBuilder::mergeRun(const SkPaint &font, SkTextBlob::GlyphPositioni
         return false;
     }
 
-    size_t sizeDelta = SkTextBlob::RunRecord::StorageSize(run->glyphCount() + count, positioning) -
-                       SkTextBlob::RunRecord::StorageSize(run->glyphCount(), positioning);
+    size_t sizeDelta = SkTextBlob::RunRecord::StorageSize(run->glyphCount() + count, 0, positioning) -
+                       SkTextBlob::RunRecord::StorageSize(run->glyphCount(), 0, positioning);
     this->reserve(sizeDelta);
 
     // reserve may have realloced
@@ -553,24 +652,29 @@ bool SkTextBlobBuilder::mergeRun(const SkPaint &font, SkTextBlob::GlyphPositioni
 
 void SkTextBlobBuilder::allocInternal(const SkPaint &font,
                                       SkTextBlob::GlyphPositioning positioning,
-                                      int count, SkPoint offset, const SkRect* bounds) {
+                                      int count, int textSize, SkPoint offset, const SkRect* bounds) {
     SkASSERT(count > 0);
+    SkASSERT(textSize >= 0);
     SkASSERT(SkPaint::kGlyphID_TextEncoding == font.getTextEncoding());
 
-    if (!this->mergeRun(font, positioning, count, offset)) {
+    if (textSize != 0 || !this->mergeRun(font, positioning, count, offset)) {
         this->updateDeferredBounds();
 
-        size_t runSize = SkTextBlob::RunRecord::StorageSize(count, positioning);
+        size_t runSize = SkTextBlob::RunRecord::StorageSize(count, textSize, positioning);
         this->reserve(runSize);
 
         SkASSERT(fStorageUsed >= sizeof(SkTextBlob));
         SkASSERT(fStorageUsed + runSize <= fStorageSize);
 
         SkTextBlob::RunRecord* run = new (fStorage.get() + fStorageUsed)
-                                         SkTextBlob::RunRecord(count, offset, font, positioning);
-
+                                     SkTextBlob::RunRecord(count, offset, font, positioning, textSize > 0);
+        if (textSize > 0) {
+            run->setTextSize(textSize);

[f(malita), 2016/06/27 20:21:55]

Why not pass textSize to the RunRecord ctor?  Then I think we don't need the
setter anymore.

[hal.canary, 2016/06/28 15:39:13]

Done.

+        }
         fCurrentRunBuffer.glyphs = run->glyphBuffer();
         fCurrentRunBuffer.pos = run->posBuffer();
+        fCurrentRunBuffer.utf8text = run->textBuffer();
+        fCurrentRunBuffer.clusters = run->clusterBuffer();
 
         fLastRun = fStorageUsed;
         fStorageUsed += runSize;
@@ -578,6 +682,9 @@ void SkTextBlobBuilder::allocInternal(const SkPaint &font,
 
         SkASSERT(fStorageUsed <= fStorageSize);
         run->validate(fStorage.get() + fStorageUsed);
+    } else {
+        fCurrentRunBuffer.utf8text = nullptr;
+        fCurrentRunBuffer.clusters = nullptr;

[f(malita), 2016/06/27 20:21:55]

I don't think we need to clear these: textSize == 0 AND mergeRun() succeeded
(which implies textSize == 0 for prev run also).

Maybe SkASSERTs instead?

[hal.canary, 2016/06/28 15:39:12]

Done.

     }
 
     if (!fDeferredBounds) {
@@ -589,26 +696,31 @@ void SkTextBlobBuilder::allocInternal(const SkPaint &font,
     }
 }
 
-const SkTextBlobBuilder::RunBuffer& SkTextBlobBuilder::allocRun(const SkPaint& font, int count,
-                                                                SkScalar x, SkScalar y,
-                                                                const SkRect* bounds) {
-    this->allocInternal(font, SkTextBlob::kDefault_Positioning, count, SkPoint::Make(x, y), bounds);
-
+const SkTextBlobBuilder::RunBuffer& SkTextBlobBuilder::allocRunText(const SkPaint& font, int count,
+                                                                    SkScalar x, SkScalar y,
+                                                                    int textByteCount,
+                                                                    SkString lang,
+                                                                    const SkRect* bounds) {
+    this->allocInternal(font, SkTextBlob::kDefault_Positioning, count, textByteCount, SkPoint::Make(x, y), bounds);
     return fCurrentRunBuffer;
 }
 
-const SkTextBlobBuilder::RunBuffer& SkTextBlobBuilder::allocRunPosH(const SkPaint& font, int count,
-                                                                    SkScalar y,
-                                                                    const SkRect* bounds) {
-    this->allocInternal(font, SkTextBlob::kHorizontal_Positioning, count, SkPoint::Make(0, y),
+const SkTextBlobBuilder::RunBuffer& SkTextBlobBuilder::allocRunTextPosH(const SkPaint& font, int count,
+                                                                        SkScalar y,
+                                                                        int textByteCount,
+                                                                        SkString lang,
+                                                                        const SkRect* bounds) {
+    this->allocInternal(font, SkTextBlob::kHorizontal_Positioning, count, textByteCount, SkPoint::Make(0, y),
                         bounds);
 
     return fCurrentRunBuffer;
 }
 
-const SkTextBlobBuilder::RunBuffer& SkTextBlobBuilder::allocRunPos(const SkPaint& font, int count,
-                                                                   const SkRect *bounds) {
-    this->allocInternal(font, SkTextBlob::kFull_Positioning, count, SkPoint::Make(0, 0), bounds);
+const SkTextBlobBuilder::RunBuffer& SkTextBlobBuilder::allocRunTextPos(const SkPaint& font, int count,
+                                                                       int textByteCount,
+                                                                       SkString lang,
+                                                                       const SkRect *bounds) {
+   this->allocInternal(font, SkTextBlob::kFull_Positioning, count, textByteCount, SkPoint::Make(0, 0), bounds);
 
     return fCurrentRunBuffer;
 }
@@ -631,7 +743,8 @@ const SkTextBlob* SkTextBlobBuilder::build() {
         size_t validateSize = sizeof(SkTextBlob);
         const SkTextBlob::RunRecord* run = SkTextBlob::RunRecord::First(blob);
         for (int i = 0; i < fRunCount; ++i) {
-            validateSize += SkTextBlob::RunRecord::StorageSize(run->fCount, run->fPositioning);
+            validateSize += SkTextBlob::RunRecord::StorageSize(
+                    run->fCount, run->textSize(), run->fPositioning);
             run->validate(reinterpret_cast<const uint8_t*>(blob) + fStorageUsed);
             run = SkTextBlob::RunRecord::Next(run);
         }