Allow creating a picture from skp to fail.

src/core/SkPicturePlayback.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 "SkPicturePlayback.h"
 #include "SkPictureRecord.h"
 #include "SkTypeface.h"
@@ skipping 455 matching lines @@
 
     uint32_t rbMask = 0;
     for (size_t i = 0; i < SK_ARRAY_COUNT(gSD); ++i) {
         if (pictInfoFlags & gSD[i].fSrc) {
             rbMask |= gSD[i].fDst;
         }
     }
     return rbMask;
 }
 
-void SkPicturePlayback::parseStreamTag(SkStream* stream, const SkPictInfo& info, uint32_t tag,
+bool SkPicturePlayback::parseStreamTag(SkStream* stream, const SkPictInfo& info, uint32_t tag,
                                        size_t size, SkPicture::InstallPixelRefProc proc) {
     /*
      *  By the time we encounter BUFFER_SIZE_TAG, we need to have already seen
      *  its dependents: FACTORY_TAG and TYPEFACE_TAG. These two are not required
      *  but if they are present, they need to have been seen before the buffer.
      *
      *  We assert that if/when we see either of these, that we have not yet seen
      *  the buffer tag, because if we have, then its too-late to deal with the
      *  factories or typefaces.
      */
@@ skipping 26 matching lines @@
                     // fTFPlayback asserts it never has a null, so we plop in
                     // the default here.
                     tf.reset(SkTypeface::RefDefault());
                 }
                 fTFPlayback.set(i, tf);
             }
         } break;
         case PICT_PICTURE_TAG: {
             fPictureCount = size;
             fPictureRefs = SkNEW_ARRAY(SkPicture*, fPictureCount);
-            for (int i = 0; i < fPictureCount; i++) {
+            bool success = true;
+            int i = 0;
+            for ( ; i < fPictureCount; i++) {
                 fPictureRefs[i] = SkPicture::CreateFromStream(stream, proc);
-                // CreateFromStream can only fail if PICTURE_VERSION does not match
-                // (which should never happen from here, since a sub picture will
-                // have the same PICTURE_VERSION as its parent) or if stream->read
-                // returns 0. In the latter case, we have a bug when writing the
-                // picture to begin with, which will be alerted to here.
-                SkASSERT(fPictureRefs[i] != NULL);
+                if (NULL == fPictureRefs[i]) {

[scroggo, 2013/09/26 21:06:28]

This bit is slightly different from a straight revert. The old code was calling
the SkPicture constructor with a pointer to bool for success, while a more
recent change switched to using a factory which can return NULL. So now we
compare against NULL and only need to delete up to i-1 down below.

+                    success = false;
+                    break;
+                }
+            }
+            if (!success) {
+                // Delete all of the pictures that were already created (up to but excluding i):
+                for (int j = 0; j < i; j++) {
+                    fPictureRefs[j]->unref();
+                }
+                // Delete the array
+                SkDELETE_ARRAY(fPictureRefs);
+                fPictureCount = 0;
+                return false;
             }
         } break;
         case PICT_BUFFER_SIZE_TAG: {
             SkAutoMalloc storage(size);
             stream->read(storage.get(), size);
 
             SkOrderedReadBuffer buffer(storage.get(), size);
             buffer.setFlags(pictInfoFlagsToReadBufferFlags(info.fFlags));
 
             fFactoryPlayback->setupBuffer(buffer);
             fTFPlayback.setupBuffer(buffer);
             buffer.setBitmapDecoder(proc);
 
             while (!buffer.eof()) {
                 tag = buffer.readUInt();
                 size = buffer.readUInt();
-                this->parseBufferTag(buffer, tag, size);
+                if (!this->parseBufferTag(buffer, tag, size)) {
+                    return false;
+                }
             }
             SkDEBUGCODE(haveBuffer = true;)
         } break;
     }
+    return true;    // success
 }
 
-void SkPicturePlayback::parseBufferTag(SkOrderedReadBuffer& buffer,
+bool SkPicturePlayback::parseBufferTag(SkOrderedReadBuffer& buffer,
                                        uint32_t tag, size_t size) {
     switch (tag) {
         case PICT_BITMAP_BUFFER_TAG: {
             fBitmaps = SkTRefArray<SkBitmap>::Create(size);
             for (size_t i = 0; i < size; ++i) {
                 SkBitmap* bm = &fBitmaps->writableAt(i);
                 buffer.readBitmap(bm);
                 bm->setImmutable();
             }
         } break;
@@ skipping 14 matching lines @@
                 fPathHeap.reset(SkNEW_ARGS(SkPathHeap, (buffer)));
             }
             break;
         case PICT_REGION_BUFFER_TAG: {
             fRegions = SkTRefArray<SkRegion>::Create(size);
             for (size_t i = 0; i < size; ++i) {
                 buffer.readRegion(&fRegions->writableAt(i));
             }
         } break;
     }
+    return true;    // success
 }
 
-SkPicturePlayback::SkPicturePlayback(SkStream* stream, const SkPictInfo& info,
+SkPicturePlayback::SkPicturePlayback(SkStream* stream, const SkPictInfo& info, bool* isValid,
                                      SkPicture::InstallPixelRefProc proc) {
     this->init();
 
+    *isValid = false;   // wait until we're done parsing to mark as true
     for (;;) {
         uint32_t tag = stream->readU32();
         if (PICT_EOF_TAG == tag) {
             break;
         }
 
         uint32_t size = stream->readU32();
-        this->parseStreamTag(stream, info, tag, size, proc);
+        if (!this->parseStreamTag(stream, info, tag, size, proc)) {
+            return; // we're invalid
+        }
     }
+    *isValid = true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////
 
 #ifdef SPEW_CLIP_SKIPPING
 struct SkipClipRec {
     int     fCount;
     size_t  fSize;
 
@@ skipping 1008 matching lines @@
     for (index = 0; index < fRegionCount; index++)
         bufferPtr += snprintf(bufferPtr, DUMP_BUFFER_SIZE - (bufferPtr - pBuffer),
             "region%p, ", &fRegions[index]);
     if (fRegionCount > 0)
         SkDebugf("%s0};\n", pBuffer);
 
     const_cast<SkPicturePlayback*>(this)->dumpStream();
 }
 
 #endif