Add a DM flag to limit the types of Codec decodes

dm/DM.cpp

Index: dm/DM.cpp
diff --git a/dm/DM.cpp b/dm/DM.cpp
index 91a92ea76be496f5e04b62198310e14c4112620d..9021f3c7894097631cef8ac3a5303a5178dc6a70 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -17,7 +17,6 @@
 #include "SkCommonFlags.h"
 #include "SkCommonFlagsConfig.h"
 #include "SkFontMgr.h"
-#include "SkForceLinking.h"
 #include "SkGraphics.h"
 #include "SkMD5.h"
 #include "SkMutex.h"
@@ -65,8 +64,8 @@ DEFINE_string(uninterestingHashesFile, "",
 
 DEFINE_int32(shards, 1, "We're splitting source data into this many shards.");
 DEFINE_int32(shard,  0, "Which shard do I run?");
+DEFINE_bool(simpleCodec, false, "Only decode images to native scale");

[scroggo, 2016/02/25 17:08:36]

Alternatively, we can set this to true as the default, and update dm_flags.py to
set it to false. When running locally, I often just want to verify that decoding
worked as I expected for the normal case. Gold will help us sort out the rest,
but I hate searching through all those folders to find the basic one I want.

(FWIW, this CL cuts us down to three folders per config. I could cut it down to
only decoding to unpremul when simpleCodec is true, which cuts us down to one.)

[msarett, 2016/02/25 17:47:37]

Acknowledged.

 
-__SK_FORCE_IMAGE_DECODER_LINKING;
 using namespace DM;
 
 /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
@@ -239,6 +238,12 @@ static void push_src(const char* tag, ImplicitString options, Src* s) {
 
 static void push_codec_src(Path path, CodecSrc::Mode mode, CodecSrc::DstColorType dstColorType,
         SkAlphaType dstAlphaType, float scale) {
+    if (FLAGS_simpleCodec) {
+        if (mode != CodecSrc::kCodec_Mode || dstColorType != CodecSrc::kGetFromCanvas_DstColorType
+                || scale != 1.0f)
+            // Only decode in the simple case.
+            return;
+    }
     SkString folder;
     switch (mode) {
         case CodecSrc::kCodec_Mode:
@@ -355,8 +360,6 @@ static void push_codec_srcs(Path path) {
     }
 
     // Native Scales
-    // TODO (msarett): Implement scaling tests for SkImageDecoder in order to compare with these
-    //                 tests.  SkImageDecoder supports downscales by integer factors.
     // SkJpegCodec natively supports scaling to: 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875
     const float nativeScales[] = { 0.125f, 0.25f, 0.375f, 0.5f, 0.625f, 0.750f, 0.875f, 1.0f };
 
@@ -434,6 +437,10 @@ static void push_codec_srcs(Path path) {
         }
     }
 
+    if (FLAGS_simpleCodec) {
+        return;
+    }
+
     // https://bug.skia.org/4428
     bool subset = false;
     // The following image types are supported by BitmapRegionDecoder,
@@ -613,6 +620,10 @@ static bool gather_srcs() {
 
     for (auto image : images) {
         push_codec_srcs(image);
+        if (FLAGS_simpleCodec) {
+            continue;
+        }
+
         const char* ext = strrchr(image.c_str(), '.');
         if (ext && brd_supported(ext+1)) {
             push_brd_srcs(image);