Reopened: Caching the result of readPixelsSupported

src/gpu/gl/GrGLCaps.cpp

Index: src/gpu/gl/GrGLCaps.cpp
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 8f2d4c129742fb9cbcb0be099b7538fbbec386d4..c8a5292a280d77938b0a1b4ef92f21243666f0f4 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -48,6 +48,8 @@ void GrGLCaps::reset() {
     fIsCoreProfile = false;
     fFullClearIsFree = false;
     fDropsTileOnZeroDivide = false;
+
+    fReadPixelsSupportedCache.clear();
 }
 
 GrGLCaps::GrGLCaps(const GrGLCaps& caps) : GrDrawTargetCaps() {
@@ -504,7 +506,7 @@ 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 &&
@@ -560,9 +562,9 @@ void GrGLCaps::initConfigTexturableTable(const GrGLContextInfo& ctxInfo, const G
     }
 }
 
-bool GrGLCaps::readPixelsSupported(const GrGLInterface* intf,
-                                   GrGLenum format,
-                                   GrGLenum type) const {
+bool GrGLCaps::doReadPixelsSupported(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;
@@ -589,6 +591,26 @@ bool GrGLCaps::readPixelsSupported(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;