Revert of Reopened: Caching the result of readPixelsSupported (https://codereview.chromium.org/364193004/)

Reason for revert:
This appears to be causing failures on Android when running tests.

Original issue's description:
> Caching the result of readPixelsSupported
>
> The call was calling GR_GL_GetIntegerv 2 times for each readPixels
> and thus was causing a loss of performance
>
> (resubmit of issue 344793008)
>
> Benchmark url: http://packages.gkny.fr/tst/index.html
>
> BUG=skia:2681
>
> Committed: https://skia.googlesource.com/skia/+/753a2964afe5661ce9b2a8ca77ca9d0aabd3173c
>
> Committed: https://skia.googlesource.com/skia/+/8339371f1ec3c57a0741932fd96bff32c53d4e54

R=junov@chromium.org, reed@chromium.org, bsalomon@chromium.org, mtklein@google.com, bsalomon@google.com, piotaixr@chromium.org
TBR=bsalomon@chromium.org, bsalomon@google.com, junov@chromium.org, mtklein@google.com, piotaixr@chromium.org, reed@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=skia:2681

Author: bungeman@google.com

Review URL: https://codereview.chromium.org/395203002

7 files changed, 12 insertions, 252 deletions

diff --git a/gyp/core.gypi b/gyp/core.gypi
index f321f017b9..f7853f91d5 100644
--- a/gyp/core.gypi
+++ b/gyp/core.gypi
@@ -199,7 +199,6 @@
         '<(skia_src_path)/core/SkStrokerPriv.h',
         '<(skia_src_path)/core/SkTextFormatParams.h',
         '<(skia_src_path)/core/SkTextMapStateProc.h',
-        '<(skia_src_path)/core/SkTHashCache.h',
         '<(skia_src_path)/core/SkTileGrid.cpp',
         '<(skia_src_path)/core/SkTileGrid.h',
         '<(skia_src_path)/core/SkTLList.h',
diff --git a/gyp/tests.gypi b/gyp/tests.gypi
index 8542868dda..ec12461198 100644
--- a/gyp/tests.gypi
+++ b/gyp/tests.gypi
@@ -174,7 +174,6 @@
     '../tests/StrokeTest.cpp',
     '../tests/SurfaceTest.cpp',
     '../tests/TArrayTest.cpp',
-    '../tests/THashCache.cpp',
     '../tests/TLSTest.cpp',
     '../tests/TSetTest.cpp',
     '../tests/TextureCompressionTest.cpp',
diff --git a/src/core/SkTHashCache.h b/src/core/SkTHashCache.h
deleted file mode 100644
index cfee9722f2..0000000000
--- a/src/core/SkTHashCache.h
+++ /dev/null
@@ -1,77 +0,0 @@
-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkTHASHCACHE_DEFINED
-#define	SkTHASHCACHE_DEFINED
-
-#include "SkTypes.h"
-#include "SkTDynamicHash.h"
-
-template <typename T,
-typename Key,
-typename Traits = T,
-int kGrowPercent = 75 >
-class SkTHashCache : public SkNoncopyable {
-public:
-
-    SkTHashCache() {
-        this->reset();
-    }
-
-    ~SkTHashCache() {
-        this->clear();
-    }
-
-    T* find(const Key& key) const {
-        return fDict->find(key);
-    }
-
-    /**
-     *  If element already in cache, return immediately the cached value
-     */
-    T& add(const T& add) {
-        Key key = Traits::GetKey(add);
-        if (T* val = this->find(key)) {
-            return *val;
-        }
-
-        T* element = SkNEW_ARGS(T, (add));
-
-        fDict->add(element);
-
-        return *element;
-    }
-
-    int size() const {
-        return fDict->count();
-    }
-
-    void reset() {
-        this->clear();
-
-        fDict.reset(SkNEW(DictType));
-    }
-
-private:
-    typedef SkTDynamicHash<T, Key, Traits, kGrowPercent> DictType;
-
-    void clear() {
-        if (fDict.get()) {
-            typename DictType::Iter it(fDict.get());
-
-            while (!it.done()) {
-                SkDELETE(&(*it));
-                ++it;
-            }
-        }
-    }
-
-    SkAutoTDelete<DictType> fDict;
-};
-
-#endif	/* SkHASHCACHE_DEFINED */
-
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 89d873bdd8..8f2d4c1297 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -48,8 +48,6 @@ void GrGLCaps::reset() {
     fIsCoreProfile = false;
     fFullClearIsFree = false;
     fDropsTileOnZeroDivide = false;
-
-    fReadPixelsSupportedCache.reset();
 }
 
 GrGLCaps::GrGLCaps(const GrGLCaps& caps) : GrDrawTargetCaps() {
@@ -506,7 +504,7 @@ void GrGLCaps::initConfigTexturableTable(const GrGLContextInfo& ctxInfo, const G
     // First check version for support
     if (kGL_GrGLStandard == standard) {
         hasETC1 = hasCompressTex2D &&
-            (version >= GR_GL_VER(4, 3) ||
+            (version >= GR_GL_VER(4, 3) || 
              ctxInfo.hasExtension("GL_ARB_ES3_compatibility"));
     } else {
         hasETC1 = hasCompressTex2D &&
@@ -562,9 +560,9 @@ void GrGLCaps::initConfigTexturableTable(const GrGLContextInfo& ctxInfo, const G
     }
 }
 
-bool GrGLCaps::doReadPixelsSupported(const GrGLInterface* intf,
-                                     GrGLenum format,
-                                     GrGLenum type) const {
+bool GrGLCaps::readPixelsSupported(const GrGLInterface* intf,
+                                   GrGLenum format,
+                                   GrGLenum type) const {
     if (GR_GL_RGBA == format && GR_GL_UNSIGNED_BYTE == type) {
         // ES 2 guarantees this format is supported
         return true;
@@ -591,26 +589,6 @@ bool GrGLCaps::doReadPixelsSupported(const GrGLInterface* intf,
     return (GrGLenum)otherFormat == format && (GrGLenum)otherType == type;
 }
 
-bool GrGLCaps::readPixelsSupported(const GrGLInterface* intf,
-                                   GrGLenum format,
-                                   GrGLenum type,
-                                   GrGLenum currFboFormat) const {
-
-    ReadPixelsSupportedFormats::Key key = {format, type, currFboFormat};
-
-    ReadPixelsSupportedFormats* cachedValue = fReadPixelsSupportedCache.find(key);
-
-    if (NULL == cachedValue) {
-        bool value = doReadPixelsSupported(intf, format, type);
-        ReadPixelsSupportedFormats newValue(key, value);
-        fReadPixelsSupportedCache.add(newValue);
-
-        return newValue.value();
-    }
-
-    return cachedValue->value();
-}
-
 void GrGLCaps::initFSAASupport(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
 
     fMSFBOType = kNone_MSFBOType;
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index 2d391b122c..ccf04fd7ba 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -11,9 +11,8 @@
 
 #include "GrDrawTargetCaps.h"
 #include "GrGLStencilBuffer.h"
-#include "SkChecksum.h"
-#include "SkTHashCache.h"
 #include "SkTArray.h"
+#include "SkTDArray.h"
 
 class GrGLContextInfo;
 
@@ -254,8 +253,7 @@ public:
     /// Does ReadPixels support the provided format/type combo?
     bool readPixelsSupported(const GrGLInterface* intf,
                              GrGLenum format,
-                             GrGLenum type,
-                             GrGLenum currFboFormat) const;
+                             GrGLenum type) const;
 
     bool isCoreProfile() const { return fIsCoreProfile; }
 
@@ -326,10 +324,6 @@ private:
     void initConfigRenderableTable(const GrGLContextInfo&);
     void initConfigTexturableTable(const GrGLContextInfo&, const GrGLInterface*);
 
-    bool doReadPixelsSupported(const GrGLInterface* intf,
-                                   GrGLenum format,
-                                   GrGLenum type) const;
-
     // tracks configs that have been verified to pass the FBO completeness when
     // used as a color attachment
     VerifiedColorConfigs fVerifiedColorConfigs;
@@ -370,46 +364,6 @@ private:
     bool fFullClearIsFree : 1;
     bool fDropsTileOnZeroDivide : 1;
 
-    class ReadPixelsSupportedFormats {
-    public:
-        struct Key {
-            GrGLenum fFormat;
-            GrGLenum fType;
-            GrGLenum fFboFormat;
-
-            bool operator==(const Key& rhs) const {
-                return fFormat == rhs.fFormat
-                        && fType == rhs.fType
-                        && fFboFormat == rhs.fFboFormat;
-            }
-
-            uint32_t getHash() const {
-                return SkChecksum::Murmur3(reinterpret_cast<const uint32_t*>(this), sizeof(*this));
-            }
-        };
-
-        ReadPixelsSupportedFormats(Key key, bool value) : fKey(key), fValue(value) {
-        }
-
-        static const Key& GetKey(const ReadPixelsSupportedFormats& element) {
-            return element.fKey;
-        }
-
-        static uint32_t Hash(const Key& key) {
-            return key.getHash();
-        }
-
-        bool value() const {
-            return fValue;
-        }
-    private:
-        Key fKey;
-        bool fValue;
-    };
-
-    mutable SkTHashCache<ReadPixelsSupportedFormats,
-                         ReadPixelsSupportedFormats::Key> fReadPixelsSupportedCache;
-
     typedef GrDrawTargetCaps INHERITED;
 };
 
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index 3eca3d6247..eddccc39f6 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -170,6 +170,8 @@ GrGpuGL::~GrGpuGL() {
 }
 
 ///////////////////////////////////////////////////////////////////////////////
+
+
 GrPixelConfig GrGpuGL::preferredReadPixelsConfig(GrPixelConfig readConfig,
                                                  GrPixelConfig surfaceConfig) const {
     if (GR_GL_RGBA_8888_PIXEL_OPS_SLOW && kRGBA_8888_GrPixelConfig == readConfig) {
@@ -180,13 +182,9 @@ GrPixelConfig GrGpuGL::preferredReadPixelsConfig(GrPixelConfig readConfig,
         // Mesa 3D takes a slow path on when reading back  BGRA from an RGBA surface and vice-versa.
         // Perhaps this should be guarded by some compiletime or runtime check.
         return surfaceConfig;
-    } else if (readConfig == kBGRA_8888_GrPixelConfig
-            && this->glCaps().readPixelsSupported(
-                this->glInterface(),
-                GR_GL_BGRA,
-                GR_GL_UNSIGNED_BYTE,
-                surfaceConfig
-            )) {
+    } else if (readConfig == kBGRA_8888_GrPixelConfig &&
+               !this->glCaps().readPixelsSupported(this->glInterface(),
+                                                   GR_GL_BGRA, GR_GL_UNSIGNED_BYTE)) {
         return kRGBA_8888_GrPixelConfig;
     } else {
         return readConfig;
@@ -715,7 +713,7 @@ bool GrGpuGL::uploadTexData(const GrGLTexture::Desc& desc,
 }
 
 // TODO: This function is using a lot of wonky semantics like, if width == -1
-// then set width = desc.fWdith ... blah. A better way to do it might be to
+// then set width = desc.fWdith ... blah. A better way to do it might be to 
 // create a CompressedTexData struct that takes a desc/ptr and figures out
 // the proper upload semantics. Then users can construct this function how they
 // see fit if they want to go against the "standard" way to do it.
diff --git a/tests/THashCache.cpp b/tests/THashCache.cpp
deleted file mode 100644
index 7797431553..0000000000
--- a/tests/THashCache.cpp
+++ /dev/null
@@ -1,91 +0,0 @@
-/*
- * 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 "Test.h"
-#include "SkTHashCache.h"
-
-
-// Tests the SkTHashCache<T> class template.
-
-struct Tint {
-    uint32_t value;
-
-    bool operator==(const Tint& rhs) const {
-        return value == rhs.value;
-    }
-};
-
-class Element {
-public:
-
-    bool operator==(const Element& rhs) const {
-        return value == rhs.value && key == rhs.key;
-    }
-
-    static const Tint& GetKey(const Element& element) {
-        return element.key;
-    }
-
-    static uint32_t Hash(const Tint& key) {
-        return key.value;
-    }
-
-    Element(Tint key, int value) : key(key), value(value) {
-    }
-
-    Tint key;
-    int value;
-};
-
-typedef SkTHashCache<Element, Tint> CacheType;
-
-DEF_TEST(THashCache, reporter) {
-    Tint k11 = {11};
-    Element e11(k11, 22);
-
-    e11.value = e11.value;
-    Element e11Collision(k11, 0);
-    //    Element e42(4, 2);
-
-    //Some tests for the class Element
-    REPORTER_ASSERT(reporter, Element::GetKey(e11) == k11);
-    REPORTER_ASSERT(reporter, Element::Hash(k11) == 11);
-
-    CacheType cache;
-
-    // Is the cahce correctly initialized ?
-    REPORTER_ASSERT(reporter, 0 == cache.size());
-    REPORTER_ASSERT(reporter, NULL == cache.find(k11));
-
-    Element& e11_c = cache.add(e11);
-    e11_c.value = e11_c.value;
-
-    // Tests for simple insertion, verifying that the returned element
-    // has the same values as the original one
-    REPORTER_ASSERT(reporter, 1 == cache.size());
-    REPORTER_ASSERT(reporter, NULL != cache.find(k11));
-    REPORTER_ASSERT(reporter, e11_c == e11);
-
-    Element& e11Collision_c = cache.add(e11Collision);
-    // Verifying that, in case of collision, the element alerady in the cache is not removed
-    REPORTER_ASSERT(reporter, e11Collision_c == e11);
-    REPORTER_ASSERT(reporter, 1 == cache.size());
-
-    Tint k42 = {42};
-    Element e42(k42, 2);
-    cache.add(e42);
-    // Can we add more than one element?
-    REPORTER_ASSERT(reporter, NULL != cache.find(k11));
-    REPORTER_ASSERT(reporter, NULL != cache.find(k42));
-    REPORTER_ASSERT(reporter, 2 == cache.size());
-
-    cache.reset();
-    // Does clear do its job?
-    REPORTER_ASSERT(reporter, 0 == cache.size());
-    REPORTER_ASSERT(reporter, NULL == cache.find(k11));
-    REPORTER_ASSERT(reporter, NULL == cache.find(k42));
-}