Add Histogram Macros to Skia

src/core/SkImageCacherator.cpp

 /*
  * 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 "SkBitmap.h"
 #include "SkBitmapCache.h"
 #include "SkImage_Base.h"
@@ skipping 222 matching lines @@
  *  We have a 5 ways to try to return a texture (in sorted order)
  *
  *  1. Check the cache for a pre-existing one
  *  2. Ask the generator to natively create one
  *  3. Ask the generator to return a compressed form that the GPU might support
  *  4. Ask the generator to return YUV planes, which the GPU can convert
  *  5. Ask the generator to return RGB(A) data, which the GPU can convert
  */
 GrTexture* SkImageCacherator::lockTexture(GrContext* ctx, const GrUniqueKey& key,
                                           const SkImage* client, SkImage::CachingHint chint) {
+    // Values representing the various texture lock paths we can take. Used for logging the path
+    // taken to a histogram.
+    enum LockTexturePath {
+        kFailure_LockTexturePath,
+        kPreExisting_LockTexturePath,
+        kNative_LockTexturePath,
+        kCompressed_LockTexturePath,
+        kYUV_LockTexturePath,
+        kRGBA_LockTexturePath,
+    };
+
+    enum { kLockTexturePathCount = kRGBA_LockTexturePath + 1 };

[ericrk, 2016/02/05 22:59:02]

This appears to be the style in Skia anyway for constants - happens to avoid the
issues that, when SK_HISTOGRAM_ENUMERATION is undefined, this is an unused var.

+
     // 1. Check the cache for a pre-existing one
     if (key.isValid()) {
         if (GrTexture* tex = ctx->textureProvider()->findAndRefTextureByUniqueKey(key)) {
+            SK_HISTOGRAM_ENUMERATION("LockTexturePath", kPreExisting_LockTexturePath,
+                                     kLockTexturePathCount);
             return tex;
         }
     }
 
     // 2. Ask the generator to natively create one
     {
         ScopedGenerator generator(this);
         SkIRect subset = SkIRect::MakeXYWH(fOrigin.x(), fOrigin.y(), fInfo.width(), fInfo.height());
         if (GrTexture* tex = generator->generateTexture(ctx, &subset)) {
+            SK_HISTOGRAM_ENUMERATION("LockTexturePath", kNative_LockTexturePath,
+                                     kLockTexturePathCount);
             return set_key_and_return(tex, key);
         }
     }
 
     const GrSurfaceDesc desc = GrImageInfoToSurfaceDesc(fInfo);
 
     // 3. Ask the generator to return a compressed form that the GPU might support
     SkAutoTUnref<SkData> data(this->refEncoded(ctx));
     if (data) {
         GrTexture* tex = load_compressed_into_texture(ctx, data, desc);
         if (tex) {
+            SK_HISTOGRAM_ENUMERATION("LockTexturePath", kCompressed_LockTexturePath,
+                                     kLockTexturePathCount);
             return set_key_and_return(tex, key);
         }
     }
 
     // 4. Ask the generator to return YUV planes, which the GPU can convert
     {
         ScopedGenerator generator(this);
         Generator_GrYUVProvider provider(generator);
         GrTexture* tex = provider.refAsTexture(ctx, desc, true);
         if (tex) {
+            SK_HISTOGRAM_ENUMERATION("LockTexturePath", kYUV_LockTexturePath,
+                                     kLockTexturePathCount);
             return set_key_and_return(tex, key);
         }
     }
 
     // 5. Ask the generator to return RGB(A) data, which the GPU can convert
     SkBitmap bitmap;
     if (this->tryLockAsBitmap(&bitmap, client, chint)) {
         GrTexture* tex = GrUploadBitmapToTexture(ctx, bitmap);
         if (tex) {
+            SK_HISTOGRAM_ENUMERATION("LockTexturePath", kRGBA_LockTexturePath,
+                                     kLockTexturePathCount);
             return set_key_and_return(tex, key);
         }
     }
+    SK_HISTOGRAM_ENUMERATION("LockTexturePath", kFailure_LockTexturePath,
+                             kLockTexturePathCount);
     return nullptr;
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 GrTexture* SkImageCacherator::lockAsTexture(GrContext* ctx, const GrTextureParams& params,
                                             const SkImage* client, SkImage::CachingHint chint) {
     if (!ctx) {
         return nullptr;
     }
 
     return GrImageTextureMaker(ctx, this, client, chint).refTextureForParams(params);
 }
 
 #else
 
 GrTexture* SkImageCacherator::lockAsTexture(GrContext* ctx, const GrTextureParams&,
                                             const SkImage* client, SkImage::CachingHint) {
     return nullptr;
 }
 
 #endif