Create an SkAndroidCodec API separate from SkCodec

src/codec/SkAndroidCodec.cpp

Index: src/codec/SkAndroidCodec.cpp
diff --git a/src/codec/SkAndroidCodec.cpp b/src/codec/SkAndroidCodec.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..43ed90f6c0be67cea075f4c23f578065afae1b5e
--- /dev/null
+++ b/src/codec/SkAndroidCodec.cpp
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkAndroidCodec.h"
+#include "SkCodec.h"
+#include "SkCodecPriv.h"
+#include "SkSampledCodec.h"
+#include "SkWebpAdapterCodec.h"
+
+static bool is_valid_sample_size(int sampleSize) {
+    // FIXME: As Leon has mentioned elsewhere, surely there is also a maximum sampleSize?
+    return sampleSize > 0;
+}
+
+SkAndroidCodec::SkAndroidCodec(const SkImageInfo& info)
+    : fInfo(info)
+{}
+
+SkAndroidCodec* SkAndroidCodec::NewFromStream(SkStream* stream) {
+    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromStream(stream));
+    if (nullptr == codec) {
+        return nullptr;
+    }
+
+    switch (codec->getEncodedFormat()) {
+        case kWEBP_SkEncodedFormat:
+            return new SkWebpAdapterCodec((SkWebpCodec*) codec.detach());
+        case kPNG_SkEncodedFormat:
+        case kJPEG_SkEncodedFormat:
+            return new SkSampledCodec(codec.detach());
+        default:
+            // FIXME: SkSampledCodec is temporarily disabled for other formats
+            // while focusing on the formats that are supported by
+            // BitmapRegionDecoder.
+            return nullptr;
+    }
+}
+
+SkAndroidCodec* SkAndroidCodec::NewFromData(SkData* data) {
+    if (!data) {
+        return nullptr;
+    }
+
+    return NewFromStream(new SkMemoryStream(data));
+}
+
+SkISize SkAndroidCodec::getSampledDimensions(int sampleSize) const {
+    if (!is_valid_sample_size(sampleSize)) {
+        return SkISize::Make(0, 0);
+    }
+
+    return this->onGetSampledDimensions(sampleSize);
+}
+
+bool SkAndroidCodec::getSupportedSubset(SkIRect* desiredSubset) const {
+    if (!desiredSubset || !is_valid_subset(*desiredSubset, fInfo.dimensions())) {
+        return false;
+    }
+
+    return this->onGetSupportedSubset(desiredSubset);
+}
+
+SkISize SkAndroidCodec::getSampledSubsetDimensions(int sampleSize, const SkIRect& subset) const {
+    if (!is_valid_sample_size(sampleSize)) {
+        return SkISize::Make(0, 0);
+    }
+
+    // We require that the input subset is a subset that is supported by SkAndroidCodec.
+    // We test this by calling getSupportedSubset() and verifying that no modifications
+    // are made to the subset.
+    SkIRect copySubset = subset;
+    if (!this->getSupportedSubset(&copySubset) || copySubset != subset) {
+        return SkISize::Make(0, 0);
+    }
+
+    // If the subset is the entire image, for consistency, use onGetSampledDimensions().
+    if (fInfo.dimensions() == subset.size()) {
+        return onGetSampledDimensions(sampleSize);
+    }
+
+    // This should perhaps call a virtual function, but currently both of our subclasses
+    // want the same implementation.
+    return SkISize::Make(get_scaled_dimension(subset.width(), sampleSize),
+                get_scaled_dimension(subset.height(), sampleSize));
+}
+
+SkCodec::Result SkAndroidCodec::getAndroidPixels(const SkImageInfo& info, void* pixels,
+        size_t rowBytes, AndroidOptions* options) {
+    if (!pixels) {
+        return SkCodec::kInvalidParameters;
+    }
+    if (rowBytes < info.minRowBytes()) {
+        return SkCodec::kInvalidParameters;
+    }
+
+    AndroidOptions defaultOptions;
+    if (!options) {
+        options = &defaultOptions;
+    } else if (options->fSubset) {
+        if (!is_valid_subset(*options->fSubset, fInfo.dimensions())) {
+            return SkCodec::kInvalidParameters;
+        }
+    }
+
+    return this->onGetAndroidPixels(info, pixels, rowBytes, *options);
+}
+
+SkCodec::Result SkAndroidCodec::getAndroidPixels(const SkImageInfo& info, void* pixels,
+        size_t rowBytes) {
+    return this->getAndroidPixels(info, pixels, rowBytes, nullptr);
+}