add runtime option to provide data->imagegenerator factory

tests/ImageGeneratorTest.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * 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) {

[scroggo, 2015/07/09 19:01:15]

Why not make this its own test, with DEF_TEST?

[reed1, 2015/07/09 19:05:45]

Just style difference. When I see the output from running the tool, I'm ok with
fewer lines, so just "ImageGenerator" instead of N lines for N different ideas,
seems ok.

+    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)) {}
 };
 
 DEF_TEST(ImageGenerator, reporter) {
     MyImageGenerator ig;
     SkISize sizes[3];
     sizes[0] = SkISize::Make(200, 200);
     sizes[1] = SkISize::Make(100, 100);
     sizes[2] = SkISize::Make( 50,  50);
     void*   planes[3] = { NULL };
     size_t  rowBytes[3] = { 0 };
     SkYUVColorSpace colorSpace;
 
     // Check that the YUV decoding API does not cause any crashes
     ig.getYUV8Planes(sizes, NULL, NULL, &colorSpace);
     ig.getYUV8Planes(sizes, NULL, NULL, NULL);
     ig.getYUV8Planes(sizes, planes, NULL, NULL);
     ig.getYUV8Planes(sizes, NULL, rowBytes, NULL);
     ig.getYUV8Planes(sizes, planes, rowBytes, NULL);
     ig.getYUV8Planes(sizes, planes, rowBytes, &colorSpace);
 
     int dummy;
     planes[0] = planes[1] = planes[2] = &dummy;
     rowBytes[0] = rowBytes[1] = rowBytes[2] = 250;
 
     ig.getYUV8Planes(sizes, planes, rowBytes, &colorSpace);
+
+    test_imagegenerator_factory(reporter);
 }