From 93ca6fb91c613c7dfa287571f32c5c44a797961f Mon Sep 17 00:00:00 2001 From: Jamie Gennis Date: Sun, 30 Oct 2011 18:10:41 -0700 Subject: [PATCH] BlobCache: remove the mutex locking This change removes the mutex from the BlobCache class. The caller must be responsible for thread synchronization in order to properly implement the Flattenable interface, which is coming soon. Otherwise would be the potential for the cache contents to change between the call to the getFlattenedSize and flatten methods. Because the caller must do this synchronization anyway there's no reason to also some synchronization inside BlobCache. Change-Id: Ie1f4f6f82b78744f46a41ce863cac0cad276a20e --- include/utils/BlobCache.h | 11 +++-------- libs/utils/BlobCache.cpp | 2 -- 2 files changed, 3 insertions(+), 10 deletions(-) diff --git a/include/utils/BlobCache.h b/include/utils/BlobCache.h index dc45ff0f3..11d424666 100644 --- a/include/utils/BlobCache.h +++ b/include/utils/BlobCache.h @@ -25,8 +25,8 @@ namespace android { -// A BlobCache is an in-memory cache for binary key/value pairs. All the public -// methods are thread-safe. +// A BlobCache is an in-memory cache for binary key/value pairs. A BlobCache +// does NOT provide any thread-safety guarantees. // // The cache contents can be serialized to a file and reloaded in a subsequent // execution of the program. This serialization is non-portable and should only @@ -166,17 +166,12 @@ private: size_t mTotalSize; // mRandState is the pseudo-random number generator state. It is passed to - // nrand48 to generate random numbers when needed. It must be protected by - // mMutex. + // nrand48 to generate random numbers when needed. unsigned short mRandState[3]; // mCacheEntries stores all the cache entries that are resident in memory. // Cache entries are added to it by the 'set' method. SortedVector mCacheEntries; - - // mMutex is used to synchronize access to all member variables. It must be - // locked any time the member variables are written or read. - Mutex mMutex; }; } diff --git a/libs/utils/BlobCache.cpp b/libs/utils/BlobCache.cpp index 590576a8d..15155b25d 100644 --- a/libs/utils/BlobCache.cpp +++ b/libs/utils/BlobCache.cpp @@ -67,7 +67,6 @@ void BlobCache::set(const void* key, size_t keySize, const void* value, return; } - Mutex::Autolock lock(mMutex); sp dummyKey(new Blob(key, keySize, false)); CacheEntry dummyEntry(dummyKey, NULL); @@ -129,7 +128,6 @@ size_t BlobCache::get(const void* key, size_t keySize, void* value, keySize, mMaxKeySize); return 0; } - Mutex::Autolock lock(mMutex); sp dummyKey(new Blob(key, keySize, false)); CacheEntry dummyEntry(dummyKey, NULL); ssize_t index = mCacheEntries.indexOf(dummyEntry);