Ensure blob typeface information survives SkGPipe serialization.

src/pipe/SkGPipeWrite.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAnnotation.h"
 #include "SkBitmapDevice.h"
 #include "SkBitmapHeap.h"
 #include "SkCanvas.h"
 #include "SkColorFilter.h"
 #include "SkData.h"
 #include "SkDrawLooper.h"
 #include "SkGPipe.h"
 #include "SkGPipePriv.h"
 #include "SkImageFilter.h"
 #include "SkMaskFilter.h"
 #include "SkWriteBuffer.h"
 #include "SkPaint.h"
 #include "SkPatchUtils.h"
 #include "SkPathEffect.h"
 #include "SkPictureFlat.h"
+#include "SkPtrRecorder.h"
 #include "SkRasterizer.h"
 #include "SkRRect.h"
 #include "SkShader.h"
 #include "SkStream.h"
 #include "SkTextBlob.h"
 #include "SkTSearch.h"
 #include "SkTypeface.h"
 #include "SkWriter32.h"
 
 enum {
     kSizeOfFlatRRect = sizeof(SkRect) + 4 * sizeof(SkVector)
 };
 

[robertphillips, 2014/09/15 18:13:03]

is_cross_process ?

[f(malita), 2014/09/15 21:51:19]

Done.

 static bool isCrossProcess(uint32_t flags) {
     return SkToBool(flags & SkGPipeWriter::kCrossProcess_Flag);
 }
 
 static SkFlattenable* get_paintflat(const SkPaint& paint, unsigned paintFlat) {
     SkASSERT(paintFlat < kCount_PaintFlats);
     switch (paintFlat) {
         case kColorFilter_PaintFlat:    return paint.getColorFilter();
         case kDrawLooper_PaintFlat:     return paint.getLooper();
         case kMaskFilter_PaintFlat:     return paint.getMaskFilter();
@@ skipping 889 matching lines @@
         }
     }
 }
 
 void SkGPipeCanvas::onDrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y,
                                    const SkPaint& paint) {
     NOTIFY_SETUP(this);
     this->writePaint(paint);
 
     // FIXME: this is inefficient but avoids duplicating the blob serialization logic.
+    SkRefCntSet typefaceSet;
     SkWriteBuffer blobBuffer;
+    blobBuffer.setTypefaceRecorder(&typefaceSet);
     blob->flatten(blobBuffer);
 
-    size_t size = sizeof(uint32_t) + 2 * sizeof(SkScalar) + blobBuffer.bytesWritten();
+    // Unlike most draw ops (which only use one paint/typeface), text blobs may reference
+    // an arbitrary number of typefaces. Since the one-paint-per-op model is not applicable,
+    // we need to serialize these explicitly.
+    int typefaceCount = typefaceSet.count();
+    size_t typefaceSize = isCrossProcess(fFlags) ? sizeof(uint32_t) : sizeof(void*);
+    SkAutoSTMalloc<16, SkTypeface*> storage(typefaceCount);
+    SkTypeface** array = storage.get();
+    typefaceSet.copyToArray((SkRefCnt**)array);
+
+    // We need to convert to IDs before we start writing the blob as the lookup may write out
+    // kDef_Typeface_DrawOp blocks for new typefaces.
+    if (isCrossProcess(fFlags)) {
+        uint32_t* typefaceIDs = reinterpret_cast<uint32_t*>(array);
+        for (int i = 0; i < typefaceCount; ++i) {
+            // This overlaps/overrides 'array', but should be safe given
+            // that sizeof(uint32_t) <= sizeof(SkTypeface*)
+            typefaceIDs[i] = this->getTypefaceID(array[i]);

[mtklein, 2014/09/12 23:09:29]

I can't help but think that if onDrawTextBlob() looked like this
{
  isCrossProcess(fFlags) ? this->blobCrossProcess(blob,x,y,p)
                         : this->blobInProcess(blob,x,y,p);
}

we'd be much less inclined to do weird things with memory and casts that require
explanatory comments.

[reed1, 2014/09/15 14:13:39]

Hmm, seems like most of this function is common w/ or w/o xprocess. What if we
just had an either/or set of helpers to build the typeface list?

[f(malita), 2014/09/15 21:51:19]

Added a couple of helpers to munge the typeface buffer, does it look nicer?

+        }
+    }
+
+    // blob byte count + typeface count + x + y + blob data + an index (cross-process)
+    // or pointer (in-process) for each typeface
+    size_t size = 2 * sizeof(uint32_t)
+                + 2 * sizeof(SkScalar)
+                + blobBuffer.bytesWritten()
+                + typefaceCount * typefaceSize;
+
     if (this->needOpBytes(size)) {
         this->writeOp(kDrawTextBlob_DrawOp);
+        size_t initialOffset = fWriter.bytesWritten();
+
         fWriter.writeScalar(x);
         fWriter.writeScalar(y);
+
+        fWriter.write32(typefaceCount);
+        fWriter.write(array, typefaceCount * typefaceSize);
+
         fWriter.write32(SkToU32(blobBuffer.bytesWritten()));
         uint32_t* pad = fWriter.reservePad(blobBuffer.bytesWritten());
         blobBuffer.writeToMemory(pad);
+
+        SkASSERT(initialOffset + size == fWriter.bytesWritten());
     }
 }
 
 void SkGPipeCanvas::onDrawPicture(const SkPicture* picture, const SkMatrix* matrix,
                                   const SkPaint* paint) {
     // we want to playback the picture into individual draw calls
     //
     // todo: do we always have to unroll? If the pipe is not cross-process, seems like
     // we could just ref the picture and move on...? <reed, scroggo>
     //
@@ skipping 368 matching lines @@
     return fCanvas->shuttleBitmap(bitmap, slot);
 }
 
 void BitmapShuttle::removeCanvas() {
     if (NULL == fCanvas) {
         return;
     }
     fCanvas->unref();
     fCanvas = NULL;
 }