add runtime option to provide data->imagegenerator factory

BUG=skia:

Review URL: https://codereview.chromium.org/1229933003

12 files changed, 82 insertions, 13 deletions

diff --git a/gm/factory.cpp b/gm/factory.cpp
index 4af37636f9..0a938629b9 100644
--- a/gm/factory.cpp
+++ b/gm/factory.cpp
@@ -36,7 +36,7 @@ protected:
             // bitmap is unlocked.
             SkAutoTUnref<SkDiscardableMemoryPool> pool(
                 SkDiscardableMemoryPool::Create(1));
-            SkAssertResult(SkInstallDiscardablePixelRef(SkImageGenerator::NewFromData(data),
+            SkAssertResult(SkInstallDiscardablePixelRef(SkImageGenerator::NewFromEncoded(data),
                                                         NULL, &fBitmap, pool));
         }
     }
diff --git a/gm/mipmap.cpp b/gm/mipmap.cpp
index 2d4ee0d26e..ad45a17e86 100644
--- a/gm/mipmap.cpp
+++ b/gm/mipmap.cpp
@@ -29,7 +29,7 @@ static SkImage* make_image() {
 }
 
 static void test_mip(SkCanvas* canvas) {
-    SkAutoTUnref<SkImage> img(make_image());//SkImage::NewFromData(data));
+    SkAutoTUnref<SkImage> img(make_image());//SkImage::NewFromEncoded(data));
 
     SkPaint paint;
     const SkRect dst = SkRect::MakeWH(177, 15);
diff --git a/include/core/SkGraphics.h b/include/core/SkGraphics.h
index ea74c586d2..e552633d5f 100644
--- a/include/core/SkGraphics.h
+++ b/include/core/SkGraphics.h
@@ -10,6 +10,9 @@
 
 #include "SkTypes.h"
 
+class SkData;
+class SkImageGenerator;
+
 class SK_API SkGraphics {
 public:
     /**
@@ -140,6 +143,16 @@ public:
      *  global font cache.
      */
     static void SetTLSFontCacheLimit(size_t bytes);
+
+    typedef SkImageGenerator* (*ImageGeneratorFromEncodedFactory)(SkData*);
+
+    /**
+     *  To instantiate images from encoded data, first looks at this runtime function-ptr. If it
+     *  exists, it is called to create an SkImageGenerator from SkData. If there is no function-ptr
+     *  or there is, but it returns NULL, then skia will call its internal default implementation.
+     */
+    static ImageGeneratorFromEncodedFactory GetImageGeneratorFromEncodedFactory();
+    static void SetImageGeneratorFromEncodedFactory(ImageGeneratorFromEncodedFactory);
 };
 
 class SkAutoGraphics {
diff --git a/include/core/SkImageGenerator.h b/include/core/SkImageGenerator.h
index a398697e6b..46001c8537 100644
--- a/include/core/SkImageGenerator.h
+++ b/include/core/SkImageGenerator.h
@@ -199,7 +199,7 @@ public:
      *  this returns a new ImageGenerator for it. Otherwise this returns NULL. Either way
      *  the caller is still responsible for managing their ownership of the data.
      */
-    static SkImageGenerator* NewFromData(SkData*);
+    static SkImageGenerator* NewFromEncoded(SkData*);
 
 protected:
     SkImageGenerator(const SkImageInfo& info) : fInfo(info) {}
@@ -220,6 +220,8 @@ protected:
 
 private:
     const SkImageInfo fInfo;
+
+    static SkImageGenerator* NewFromEncodedImpl(SkData*);
 };
 
 #endif  // SkImageGenerator_DEFINED
diff --git a/src/core/SkImageGenerator.cpp b/src/core/SkImageGenerator.cpp
index b4a3fc21c8..7da4d40b0c 100644
--- a/src/core/SkImageGenerator.cpp
+++ b/src/core/SkImageGenerator.cpp
@@ -130,3 +130,29 @@ bool SkImageGenerator::onGetPixels(const SkImageInfo& info, void* dst, size_t rb
     return false;
 }
 #endif
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+#include "SkGraphics.h"
+
+static SkGraphics::ImageGeneratorFromEncodedFactory gImageGeneratorFromEncodedFactory;
+
+SkGraphics::ImageGeneratorFromEncodedFactory SkGraphics::GetImageGeneratorFromEncodedFactory() {
+    return gImageGeneratorFromEncodedFactory;
+}
+
+void SkGraphics::SetImageGeneratorFromEncodedFactory(ImageGeneratorFromEncodedFactory factory) {
+    gImageGeneratorFromEncodedFactory = factory;
+}
+
+SkImageGenerator* SkImageGenerator::NewFromEncoded(SkData* data) {
+    if (NULL == data) {
+        return NULL;
+    }
+    if (gImageGeneratorFromEncodedFactory) {
+        if (SkImageGenerator* generator = gImageGeneratorFromEncodedFactory(data)) {
+            return generator;
+        }
+    }
+    return SkImageGenerator::NewFromEncodedImpl(data);
+}
diff --git a/src/image/SkImage.cpp b/src/image/SkImage.cpp
index e8a3ead2b1..ff0b8c9819 100644
--- a/src/image/SkImage.cpp
+++ b/src/image/SkImage.cpp
@@ -76,7 +76,7 @@ SkImage* SkImage::NewFromEncoded(SkData* encoded, const SkIRect* subset) {
     if (NULL == encoded || 0 == encoded->size()) {
         return NULL;
     }
-    SkImageGenerator* generator = SkImageGenerator::NewFromData(encoded);
+    SkImageGenerator* generator = SkImageGenerator::NewFromEncoded(encoded);
     return generator ? SkImage::NewFromGenerator(generator, subset) : NULL;
 }
 
diff --git a/src/lazy/SkDiscardablePixelRef.cpp b/src/lazy/SkDiscardablePixelRef.cpp
index 19bfc8ccc7..4f9178e6e1 100644
--- a/src/lazy/SkDiscardablePixelRef.cpp
+++ b/src/lazy/SkDiscardablePixelRef.cpp
@@ -150,6 +150,6 @@ bool SkInstallDiscardablePixelRef(SkImageGenerator* generator, SkBitmap* dst) {
 }
 
 bool SkInstallDiscardablePixelRef(SkData* encoded, SkBitmap* dst) {
-    SkImageGenerator* generator = SkImageGenerator::NewFromData(encoded);
+    SkImageGenerator* generator = SkImageGenerator::NewFromEncoded(encoded);
     return generator ? SkInstallDiscardablePixelRef(generator, NULL, dst, NULL) : false;
 }
diff --git a/src/ports/SkImageGenerator_none.cpp b/src/ports/SkImageGenerator_none.cpp
index 78d408aa35..c0126cae79 100644
--- a/src/ports/SkImageGenerator_none.cpp
+++ b/src/ports/SkImageGenerator_none.cpp
@@ -7,6 +7,6 @@
 
 #include "SkImageGenerator.h"
 
-SkImageGenerator* SkImageGenerator::NewFromData(SkData*) {
+SkImageGenerator* SkImageGenerator::NewFromEncodedImpl(SkData*) {
     return NULL;
 }
diff --git a/src/ports/SkImageGenerator_skia.cpp b/src/ports/SkImageGenerator_skia.cpp
index f972253306..1dbc9a5f33 100644
--- a/src/ports/SkImageGenerator_skia.cpp
+++ b/src/ports/SkImageGenerator_skia.cpp
@@ -108,11 +108,7 @@ private:
     typedef SkImageGenerator INHERITED;
 };
 
-SkImageGenerator* SkImageGenerator::NewFromData(SkData* data) {
-    if (NULL == data) {
-        return NULL;
-    }
-
+SkImageGenerator* SkImageGenerator::NewFromEncodedImpl(SkData* data) {
     SkMemoryStream stream(data->data(), data->size(), false);
     SkImageDecoder* decoder = SkImageDecoder::Factory(&stream);
     if (NULL == decoder) {
diff --git a/tests/CachedDecodingPixelRefTest.cpp b/tests/CachedDecodingPixelRefTest.cpp
index a2032ba1de..78adc34d5a 100644
--- a/tests/CachedDecodingPixelRefTest.cpp
+++ b/tests/CachedDecodingPixelRefTest.cpp
@@ -142,7 +142,7 @@ static void test_three_encodings(skiatest::Reporter* reporter,
 
 ////////////////////////////////////////////////////////////////////////////////
 static bool install_skCachingPixelRef(SkData* encoded, SkBitmap* dst) {
-    return SkCachingPixelRef::Install(SkImageGenerator::NewFromData(encoded), dst);
+    return SkCachingPixelRef::Install(SkImageGenerator::NewFromEncoded(encoded), dst);
 }
 static bool install_skDiscardablePixelRef(SkData* encoded, SkBitmap* dst) {
     // Use system-default discardable memory.
diff --git a/tests/ImageGeneratorTest.cpp b/tests/ImageGeneratorTest.cpp
index 94867bc945..c856d8be60 100644
--- a/tests/ImageGeneratorTest.cpp
+++ b/tests/ImageGeneratorTest.cpp
@@ -5,9 +5,39 @@
  * found in the LICENSE file.
  */
 
+#include "SkData.h"
+#include "SkGraphics.h"
 #include "SkImageGenerator.h"
 #include "Test.h"
 
+static SkImageGenerator* my_factory(SkData* data) {
+    int* ptr = *(int**)data->data();
+    *ptr = 1;   // signal that we were called
+    return NULL;
+}
+
+static void test_imagegenerator_factory(skiatest::Reporter* reporter) {
+    int factoryHasBeenCalled = 0;
+    int* sentinelPtr = &factoryHasBeenCalled;
+    SkData* data = SkData::NewWithCopy(&sentinelPtr, sizeof(sentinelPtr));
+
+    SkImageGenerator* gen;
+    REPORTER_ASSERT(reporter, 0 == *sentinelPtr);
+
+    gen = SkImageGenerator::NewFromEncoded(data);
+    REPORTER_ASSERT(reporter, NULL == gen);
+    REPORTER_ASSERT(reporter, 0 == *sentinelPtr);
+
+    // Test is racy, in that it hopes no other thread is changing this global...
+    SkGraphics::ImageGeneratorFromEncodedFactory prev =
+                                                SkGraphics::GetImageGeneratorFromEncodedFactory();
+    SkGraphics::SetImageGeneratorFromEncodedFactory(my_factory);
+    gen = SkImageGenerator::NewFromEncoded(data);
+    REPORTER_ASSERT(reporter, NULL == gen);
+    REPORTER_ASSERT(reporter, 1 == *sentinelPtr);
+    SkGraphics::SetImageGeneratorFromEncodedFactory(prev);
+}
+
 class MyImageGenerator : public SkImageGenerator {
 public:
     MyImageGenerator() : SkImageGenerator(SkImageInfo::MakeN32Premul(0, 0)) {}
@@ -36,4 +66,6 @@ DEF_TEST(ImageGenerator, reporter) {
     rowBytes[0] = rowBytes[1] = rowBytes[2] = 250;
 
     ig.getYUV8Planes(sizes, planes, rowBytes, &colorSpace);
+
+    test_imagegenerator_factory(reporter);
 }
diff --git a/tools/LazyDecodeBitmap.cpp b/tools/LazyDecodeBitmap.cpp
index 6c655da9e9..bcd8cad44d 100644
--- a/tools/LazyDecodeBitmap.cpp
+++ b/tools/LazyDecodeBitmap.cpp
@@ -28,7 +28,7 @@ bool sk_tools::LazyDecodeBitmap(const void* src, size_t length, SkBitmap* dst) {
         return false;
     }
 
-    SkAutoTDelete<SkImageGenerator> gen(SkImageGenerator::NewFromData(data));
+    SkAutoTDelete<SkImageGenerator> gen(SkImageGenerator::NewFromEncoded(data));
     if (NULL == gen.get()) {
         return false;
     }