From 61010772e59638ff97acb3200a4ec88aa55037a6 Mon Sep 17 00:00:00 2001
From: mtklein <mtklein@google.com>
Date: Wed, 25 Feb 2015 08:27:41 -0800
Subject: [PATCH] Revert of fAddedToCache doesn't need to be atomic. (patchset
 #1 id:1 of https://codereview.chromium.org/960573002/)

Reason for revert:
Yes it does.  notifyAddedToCache() must be thread-safe.

Original issue's description:
> fAddedToCache doesn't need to be atomic.
>
> It's only ever read or set from non-threadsafe methods.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/fbe0edfec4fed2a09e12b049d527d280f16e75b3

TBR=reed@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/959763002
---
 include/core/SkPixelRef.h | 4 ++--
 src/core/SkPixelRef.cpp   | 9 +++++----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/core/SkPixelRef.h b/include/core/SkPixelRef.h
index daf6af1..01303e5 100644
--- a/include/core/SkPixelRef.h
+++ b/include/core/SkPixelRef.h
@@ -248,7 +248,7 @@ public:
     // Call when this pixelref is part of the key to a resourcecache entry. This allows the cache
     // to know automatically those entries can be purged when this pixelref is changed or deleted.
     void notifyAddedToCache() {
-        fAddedToCache = true;
+        fAddedToCache.store(true);
     }
 
 protected:
@@ -321,7 +321,7 @@ private:
 
     mutable SkAtomic<uint32_t> fGenerationID;
     mutable SkAtomic<bool>     fUniqueGenerationID;
-    bool fAddedToCache;
+    SkAtomic<bool>             fAddedToCache;
 #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
     const uint32_t fStableID;
 #endif
diff --git a/src/core/SkPixelRef.cpp b/src/core/SkPixelRef.cpp
index 24ee473..560748c 100644
--- a/src/core/SkPixelRef.cpp
+++ b/src/core/SkPixelRef.cpp
@@ -100,7 +100,7 @@ SkPixelRef::SkPixelRef(const SkImageInfo& info)
     this->needsNewGenID();
     fIsImmutable = false;
     fPreLocked = false;
-    fAddedToCache = false;
+    fAddedToCache.store(false);
 }
 
 
@@ -116,7 +116,7 @@ SkPixelRef::SkPixelRef(const SkImageInfo& info, SkBaseMutex* mutex)
     this->needsNewGenID();
     fIsImmutable = false;
     fPreLocked = false;
-    fAddedToCache = false;
+    fAddedToCache.store(false);
 }
 
 SkPixelRef::~SkPixelRef() {
@@ -227,9 +227,10 @@ void SkPixelRef::callGenIDChangeListeners() {
             fGenIDChangeListeners[i]->onChange();
         }
 
-        if (fAddedToCache) {
+        // TODO: SkAtomic could add "old_value = atomic.xchg(new_value)" to make this clearer.
+        if (fAddedToCache.load()) {
             SkNotifyBitmapGenIDIsStale(this->getGenerationID());
-            fAddedToCache = false;
+            fAddedToCache.store(false);
         }
     }
     // Listeners get at most one shot, so whether these triggered or not, blow them away.
-- 
2.7.4