Expand pixelref to return SkImageInfo and rowbytes

src/core/SkMallocPixelRef.cpp

Index: src/core/SkMallocPixelRef.cpp
diff --git a/src/core/SkMallocPixelRef.cpp b/src/core/SkMallocPixelRef.cpp
index f229e9de34d0fa8dbdd29304dd0ac0f7a78e5611..69fde2c17e60f8196c145f33e9754fefb347147f 100644
--- a/src/core/SkMallocPixelRef.cpp
+++ b/src/core/SkMallocPixelRef.cpp
@@ -1,27 +1,105 @@
-
 /*
  * 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 "SkMallocPixelRef.h"
 #include "SkBitmap.h"
 #include "SkFlattenableBuffers.h"
 
-SkMallocPixelRef::SkMallocPixelRef(void* storage, size_t size,
-                                   SkColorTable* ctable, bool ownPixels) {
-    if (NULL == storage) {
-        SkASSERT(ownPixels);
-        storage = sk_malloc_throw(size);
+static bool check_info(const SkImageInfo& info, SkColorTable* ctable) {
+    if (info.fWidth < 0 ||
+        info.fHeight < 0 ||
+        (unsigned)info.fColorType > (unsigned)kLastEnum_SkColorType ||
+        (unsigned)info.fAlphaType > (unsigned)kLastEnum_SkAlphaType)
+    {
+        return false;
+    }
+    
+    // these seem like good checks, but currently we have (at least) tests
+    // that expect the pixelref to succeed even when there is a mismatch
+    // with colortables. fix?
+#if 0
+    if (kIndex8_SkColorType == info.fColorType && NULL == ctable) {
+        return false;
+    }
+    if (kIndex8_SkColorType != info.fColorType && NULL != ctable) {
+        return false;
+    }
+#endif
+    return true;
+}
+
+SkMallocPixelRef* SkMallocPixelRef::NewDirect(const SkImageInfo& info,

[mtklein, 2013/12/04 22:46:00]

I would assert that this may be better thought of as a different type than
SkMallocPixelRef.  There's not really any Mallociness to it.

[reed1, 2013/12/05 13:32:39]

Agreed. May move this kind of factory out to SkPixelRef

+                                              void* addr,
+                                              size_t rowBytes,
+                                              SkColorTable* ctable) {
+    if (!check_info(info, ctable)) {
+        return NULL;
+    }
+    return SkNEW_ARGS(SkMallocPixelRef, (info, addr, rowBytes, ctable, false));
+}
+
+SkMallocPixelRef* SkMallocPixelRef::NewAllocate(const SkImageInfo& info,
+                                                size_t requestedRowBytes,
+                                                SkColorTable* ctable) {
+    if (!check_info(info, ctable)) {
+        return NULL;
+    }
+
+    int32_t minRB = info.minRowBytes();
+    if (minRB < 0) {
+        return NULL;    // allocation will be too large
+    }
+    if (requestedRowBytes > 0 && (int32_t)requestedRowBytes < minRB) {
+        return NULL;    // cannot meet requested rowbytes
+    }
+
+    int32_t rowBytes;
+    if (requestedRowBytes) {
+        rowBytes = requestedRowBytes;
+    } else {
+        rowBytes = minRB;
     }
+
+    Sk64 bigSize;
+    bigSize.setMul(info.fHeight, rowBytes);
+    if (!bigSize.is32()) {
+        return NULL;
+    }
+
+    size_t size = bigSize.get32();
+    void* addr = sk_malloc_flags(size, 0);
+    if (NULL == addr) {
+        return NULL;
+    }
+
+    return SkNEW_ARGS(SkMallocPixelRef, (info, addr, rowBytes, ctable, true));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+SkMallocPixelRef::SkMallocPixelRef(const SkImageInfo& info, void* storage,
+                                   size_t rowBytes, SkColorTable* ctable,
+                                   bool ownsPixels)
+    : fOwnPixels(ownsPixels)
+{
+    SkASSERT(check_info(info, ctable));
+    SkASSERT(rowBytes >= info.minRowBytes());
+
+    if (kIndex8_SkColorType != info.fColorType) {
+        ctable = NULL;
+    }
+
     fStorage = storage;
-    fSize = size;
     fCTable = ctable;
+    fRB = rowBytes;
+    fInfo = info;
     SkSafeRef(ctable);
-    fOwnPixels = ownPixels;
-
-    this->setPreLocked(fStorage, fCTable);
+    
+    this->setPreLocked(fInfo, fStorage, fRB, fCTable);
 }
 
 SkMallocPixelRef::~SkMallocPixelRef() {
@@ -31,9 +109,16 @@ SkMallocPixelRef::~SkMallocPixelRef() {
     }
 }
 
-void* SkMallocPixelRef::onLockPixels(SkColorTable** ct) {
-    *ct = fCTable;
-    return fStorage;
+bool SkMallocPixelRef::onGetInfo(SkImageInfo* info) {
+    *info = fInfo;
+    return true;
+}
+
+bool SkMallocPixelRef::onNewLockPixels(LockRec* rec) {
+    rec->fPixels = fStorage;
+    rec->fRowBytes = fRB;
+    rec->fColorTable = fCTable;
+    return true;
 }
 
 void SkMallocPixelRef::onUnlockPixels() {
@@ -43,7 +128,13 @@ void SkMallocPixelRef::onUnlockPixels() {
 void SkMallocPixelRef::flatten(SkFlattenableWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
 
-    buffer.writeByteArray(fStorage, fSize);
+    fInfo.flatten(buffer);
+    buffer.write32(fRB);
+
+    // TODO: replace this bulk write with a chunky one that can trim off any
+    // trailing bytes on each scanline (in case rowbytes > width*size)
+    size_t size = this->computeMinSize();
+    buffer.writeByteArray(fStorage, size);
     buffer.writeBool(fCTable != NULL);
     if (fCTable) {
         fCTable->writeToBuffer(buffer);
@@ -51,16 +142,19 @@ void SkMallocPixelRef::flatten(SkFlattenableWriteBuffer& buffer) const {
 }
 
 SkMallocPixelRef::SkMallocPixelRef(SkFlattenableReadBuffer& buffer)
-        : INHERITED(buffer, NULL) {
-    fSize = buffer.getArrayCount();
-    fStorage = sk_malloc_throw(fSize);
-    buffer.readByteArray(fStorage, fSize);
+    : INHERITED(buffer, NULL)
+    , fOwnPixels(true)
+{
+    fInfo.unflatten(buffer);
+    fRB = buffer.read32();
+    size_t size = this->computeMinSize();
+    fStorage = sk_malloc_throw(size);
+    buffer.readByteArray(fStorage, size);
     if (buffer.readBool()) {
         fCTable = SkNEW_ARGS(SkColorTable, (buffer));
     } else {
         fCTable = NULL;
     }
-    fOwnPixels = true;
 
-    this->setPreLocked(fStorage, fCTable);
+    this->setPreLocked(fInfo, fStorage, fRB, fCTable);
 }