Break up SkLazyPixelRef functionally into class hierarchy.

src/lazy/SkLazyCachingPixelRef.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "Sk64.h"
+#include "SkColorTable.h"
+#include "SkData.h"
+#include "SkImageDecoder.h"
+#include "SkImagePriv.h"
+#include "SkLazyCachingPixelRef.h"
+#include "SkScaledImageCache.h"
+#include "SkPostConfig.h"
+
+SkLazyCachingPixelRef::SkLazyCachingPixelRef(SkData* data,
+                                             SkBitmapFactory::DecodeProc proc,
+                                             SkScaledImageCache* cache)
+    : INHERITED(cache)
+    , fDecodeProc(proc) {
+    if (NULL == data) {
+        fData = SkData::NewEmpty();
+    } else {
+        fData = data;
+        fData->ref();
+    }
+    memset(&fLazilyCachedInfo, 0xFF, sizeof(fLazilyCachedInfo));
+
+    if (NULL == fDecodeProc) {  // use a reasonable default.
+        fDecodeProc = SkImageDecoder::DecodeMemoryToTarget;
+    }
+    this->setImmutable();
+}
+
+SkLazyCachingPixelRef::~SkLazyCachingPixelRef() {
+    SkASSERT(fData != NULL);
+    fData->unref();
+}
+
+bool SkLazyCachingPixelRef::onDecodeInfo(SkISize* size,
+                                         SkBitmap::Config* config,
+                                         SkAlphaType* alphaType) {
+    SkASSERT(size && config &&alphaType);
+    if (fLazilyCachedInfo.fWidth < 0) {
+        SkImage::Info info;
+        if (!fDecodeProc(fData->data(), fData->size(), &info, NULL)) {
+            return false;
+        }
+        fLazilyCachedInfo = info;
+    }
+    size->set(fLazilyCachedInfo.fWidth, fLazilyCachedInfo.fHeight);
+    *config = SkImageInfoToBitmapConfig(fLazilyCachedInfo);
+    *alphaType = fLazilyCachedInfo.fAlphaType;
+    return true;
+}
+
+bool SkLazyCachingPixelRef::onDecode(void* pixels, size_t rowBytes) {
+    SkASSERT(pixels);
+    if (fLazilyCachedInfo.fWidth <= 0) {
+        SkISize size;
+        SkBitmap::Config config;
+        SkAlphaType alphaType;
+        // The side effect of this is to set fLazilyCachedInfo
+        this->onDecodeInfo(&size, &config, &alphaType);
+    }
+    SkBitmapFactory::Target target = {pixels, rowBytes};
+    return fDecodeProc(fData->data(), fData->size(),
+                       &fLazilyCachedInfo, &target);
+}
+
+bool SkLazyCachingPixelRef::Install(SkBitmapFactory::DecodeProc proc,
+                                    SkData* data,
+                                    SkBitmap* destination,
+                                    SkScaledImageCache* cache) {
+    SkAutoTUnref<SkLazyCachingPixelRef> ref(
+        SkNEW_ARGS(SkLazyCachingPixelRef, (data, proc, cache)));
+    return ref->configure(destination) && destination->setPixelRef(ref);
+}
+