Add the ability to clear the shader disk cache.

content/browser/gpu/shader_disk_cache_impl.cc

Index: content/browser/gpu/shader_disk_cache_impl.cc
diff --git a/content/browser/gpu/shader_disk_cache.cc b/content/browser/gpu/shader_disk_cache_impl.cc
similarity index 60%
rename from content/browser/gpu/shader_disk_cache.cc
rename to content/browser/gpu/shader_disk_cache_impl.cc
index ca309370e259798aa72dcbda0b89baf470e0037a..e64a223eb175b7a6afab21ea32cc65966816f7a8 100644
--- a/content/browser/gpu/shader_disk_cache.cc
+++ b/content/browser/gpu/shader_disk_cache_impl.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "content/browser/gpu/shader_disk_cache.h"
+#include "content/browser/gpu/shader_disk_cache_impl.h"
 
 #include "base/threading/thread_checker.h"
 #include "content/browser/gpu/gpu_process_host.h"
@@ -101,6 +101,40 @@ class ShaderDiskReadHelper
   DISALLOW_COPY_AND_ASSIGN(ShaderDiskReadHelper);
 };
 
+class ShaderClearHelper
+    : public base::ThreadChecker,

[jonathan.backer, 2013/03/21 21:06:36]

nix: ThreadChecker is for CalledOnValidThread, which you are not using.

[dsinclair, 2013/03/22 18:08:23]

Done.

+      public base::RefCounted<ShaderClearHelper> {
+ public:
+  ShaderClearHelper(scoped_refptr<ShaderDiskCache> cache,
+                    const base::FilePath& path,
+                    const base::Time& delete_begin,
+                    const base::Time& delete_end,
+                    const base::Closure& callback);
+  void Clear();
+
+ private:
+  friend class base::RefCounted<ShaderClearHelper>;
+
+  enum OpType {
+    TERMINATE,
+    VERIFY_CACHE_SETUP,
+    DELETE_CACHE
+  };
+
+  ~ShaderClearHelper();
+
+  void DoClearShaderCache(int rv);
+
+  scoped_refptr<ShaderDiskCache> cache_;
+  OpType op_type_;
+  base::FilePath path_;
+  base::Time delete_begin_;
+  base::Time delete_end_;
+  base::Closure callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(ShaderClearHelper);
+};
+
 ShaderDiskCacheEntry::ShaderDiskCacheEntry(base::WeakPtr<ShaderDiskCache> cache,
                                            const std::string& key,
                                            const std::string& shader)
@@ -309,51 +343,162 @@ ShaderDiskReadHelper::~ShaderDiskReadHelper() {
                             base::Bind(&EntryCloser, entry_));
 }
 
+ShaderClearHelper::ShaderClearHelper(scoped_refptr<ShaderDiskCache> cache,
+                    const base::FilePath& path,
+                    const base::Time& delete_begin,
+                    const base::Time& delete_end,
+                    const base::Closure& callback)
+    : cache_(cache),
+      op_type_(VERIFY_CACHE_SETUP),
+      path_(path),
+      delete_begin_(delete_begin),
+      delete_end_(delete_end),
+      callback_(callback) {
+}
+
+ShaderClearHelper::~ShaderClearHelper() {

[jonathan.backer, 2013/03/21 21:06:36]

Does it matter what thread the |cache| is deleted on? If so, maybe verify that
you're on the IO thread here as well.

[dsinclair, 2013/03/22 18:08:23]

Done.

+}
+
+void ShaderClearHelper::Clear() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DoClearShaderCache(net::OK);
+}
+
+void ShaderClearHelper::DoClearShaderCache(int rv) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  while (rv != net::ERR_IO_PENDING) {
+    switch (op_type_) {
+      case VERIFY_CACHE_SETUP:
+        rv = cache_->SetAvailableCallback(
+            base::Bind(&ShaderClearHelper::DoClearShaderCache, this));
+        op_type_ = DELETE_CACHE;
+        break;
+      case DELETE_CACHE:
+        rv = cache_->Clear(
+            delete_begin_, delete_end_,
+            base::Bind(&ShaderClearHelper::DoClearShaderCache, this));
+        op_type_ = TERMINATE;
+        break;
+      case TERMINATE:
+        BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
+            base::Bind(&ShaderCacheFactoryImpl::CacheCleared,
+                       base::Unretained(ShaderCacheFactoryImpl::GetInstance()),
+                       path_));

[jonathan.backer, 2013/03/21 21:06:36]

nit: Comment for the PostTask. This won't be clear a few months down the road.
Perhaps an alternative is to take a scoped_ref on this. Then you know you won't
call the dtor.

[dsinclair, 2013/03/22 18:08:23]

Done.

+        callback_.Run();
+        rv = net::ERR_IO_PENDING;  // Break the loop.
+        break;
+      default:
+        NOTREACHED();  // Invalid state provided.
+        op_type_ = TERMINATE;
+        break;
+    }
+  }
+}
+
+// static
 ShaderCacheFactory* ShaderCacheFactory::GetInstance() {
-  return Singleton<ShaderCacheFactory,
-      LeakySingletonTraits<ShaderCacheFactory> >::get();
+  return ShaderCacheFactoryImpl::GetInstance();
+}
+
+// static
+ShaderCacheFactoryImpl* ShaderCacheFactoryImpl::GetInstance() {
+  return Singleton<ShaderCacheFactoryImpl,
+      LeakySingletonTraits<ShaderCacheFactoryImpl> >::get();
 }
 
-ShaderCacheFactory::ShaderCacheFactory() {
+ShaderCacheFactoryImpl::ShaderCacheFactoryImpl() {
 }
 
-ShaderCacheFactory::~ShaderCacheFactory() {
+ShaderCacheFactoryImpl::~ShaderCacheFactoryImpl() {
 }
 
-void ShaderCacheFactory::SetCacheInfo(int32 client_id,
-                                      const base::FilePath& path) {
-  client_id_to_path_map_[client_id] = path.Append(kGpuCachePath);
+void ShaderCacheFactoryImpl::SetCacheInfo(int32 client_id,
+                                          const base::FilePath& path) {
+  client_id_to_path_map_[client_id] = path;
 }
 
-void ShaderCacheFactory::RemoveCacheInfo(int32 client_id) {
+void ShaderCacheFactoryImpl::RemoveCacheInfo(int32 client_id) {
   client_id_to_path_map_.erase(client_id);
 }
 
-scoped_refptr<ShaderDiskCache> ShaderCacheFactory::Get(int32 client_id) {
-  ClientIdToPathMap::iterator client_iter =
+scoped_refptr<ShaderDiskCache> ShaderCacheFactoryImpl::Get(
+    int32 client_id) {
+  ClientIdToPathMap::iterator iter =
       client_id_to_path_map_.find(client_id);
-  if (client_iter == client_id_to_path_map_.end())
+  if (iter == client_id_to_path_map_.end())
     return NULL;
+  return ShaderCacheFactoryImpl::GetByPath(iter->second);
+}
 
-  ShaderCacheMap::iterator iter = shader_cache_map_.find(client_iter->second);
+scoped_refptr<ShaderDiskCache> ShaderCacheFactoryImpl::GetByPath(
+    const base::FilePath& path) {
+  ShaderCacheMap::iterator iter = shader_cache_map_.find(path);
   if (iter != shader_cache_map_.end())
     return iter->second;
 
-  ShaderDiskCache* cache = new ShaderDiskCache(client_iter->second);
+  ShaderDiskCache* cache = new ShaderDiskCache(path);
   cache->Init();
-
   return cache;
 }
 
-void ShaderCacheFactory::AddToCache(const base::FilePath& key,
-                                    ShaderDiskCache* cache) {
+void ShaderCacheFactoryImpl::AddToCache(const base::FilePath& key,
+                                        ShaderDiskCache* cache) {
   shader_cache_map_[key] = cache;
 }
 
-void ShaderCacheFactory::RemoveFromCache(const base::FilePath& key) {
+void ShaderCacheFactoryImpl::RemoveFromCache(const base::FilePath& key) {
   shader_cache_map_.erase(key);
 }
 
+void ShaderCacheFactoryImpl::ClearByPath(const base::FilePath& path,
+                                         const base::Time& delete_begin,
+                                         const base::Time& delete_end,
+                                         const base::Closure& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK(!callback.is_null());
+
+  scoped_refptr<ShaderClearHelper> helper = new ShaderClearHelper(
+      GetByPath(path), path, delete_begin, delete_end, callback);
+
+  // We could receive requests to clear the same path with different
+  // begin/end times. So, we keep a list of requests. If we haven't seen this
+  // path before we kick off the clear and add it to the list. If we have see it
+  // already, then we already have a clear running. We add this clear to the
+  // list and wait for any previous clears to finish.
+  ShaderClearMap::iterator iter = shader_clear_map_.find(path);
+  if (iter != shader_clear_map_.end()) {
+    iter->second.push(helper);
+    return;
+  }
+
+  shader_clear_map_.insert(
+      std::pair<base::FilePath, ShaderClearQueue>(path, ShaderClearQueue()));
+  shader_clear_map_[path].push(helper);
+  helper->Clear();
+}
+
+void ShaderCacheFactoryImpl::CacheCleared(const base::FilePath& path) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+
+  ShaderClearMap::iterator iter = shader_clear_map_.find(path);
+  if (iter == shader_clear_map_.end()) {
+    LOG(ERROR) << "Completed clear but missing clear helper.";
+    return;
+  }
+
+  iter->second.pop();
+
+  // If there are remaining items in the list we trigger the Clear on the
+  // next one.
+  if (!iter->second.empty()) {
+    iter->second.front()->Clear();
+    return;
+  }
+
+  shader_clear_map_.erase(path);
+}
+
 ShaderDiskCache::ShaderDiskCache(const base::FilePath& cache_path)
     : cache_available_(false),
       max_cache_size_(0),
@@ -361,11 +506,11 @@ ShaderDiskCache::ShaderDiskCache(const base::FilePath& cache_path)
       cache_path_(cache_path),
       is_initialized_(false),
       backend_(NULL) {
-  ShaderCacheFactory::GetInstance()->AddToCache(cache_path_, this);
+  ShaderCacheFactoryImpl::GetInstance()->AddToCache(cache_path_, this);
 }
 
 ShaderDiskCache::~ShaderDiskCache() {
-  ShaderCacheFactory::GetInstance()->RemoveFromCache(cache_path_);
+  ShaderCacheFactoryImpl::GetInstance()->RemoveFromCache(cache_path_);
 }
 
 void ShaderDiskCache::Init() {
@@ -377,7 +522,7 @@ void ShaderDiskCache::Init() {
 
   int rv = disk_cache::CreateCacheBackend(
       net::SHADER_CACHE,
-      cache_path_,
+      cache_path_.Append(kGpuCachePath),
       max_cache_size_,
       true,
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::CACHE),
@@ -400,16 +545,41 @@ void ShaderDiskCache::Cache(const std::string& key, const std::string& shader) {
   entry_map_[shim] = shim;
 }
 
+int ShaderDiskCache::Clear(
+    const base::Time begin_time, const base::Time end_time,
+    const net::CompletionCallback& completion_callback) {
+  int rv;
+  if (begin_time.is_null()) {
+    rv = backend_->DoomAllEntries(completion_callback);
+  } else {
+    rv = backend_->DoomEntriesBetween(begin_time, end_time,
+                                      completion_callback);
+  }
+  return rv;
+}
+
+int ShaderDiskCache::SetAvailableCallback(
+    const net::CompletionCallback& callback) {
+  if (cache_available_)
+    return net::OK;
+  available_callback_ = callback;
+  return net::ERR_IO_PENDING;
+}
+
 void ShaderDiskCache::CacheCreatedCallback(int rv) {
   if (rv != net::OK) {
     LOG(ERROR) << "Shader Cache Creation failed: " << rv;
     return;
   }
-
   cache_available_ = true;
 
   helper_ = new ShaderDiskReadHelper(AsWeakPtr(), host_id_);
   helper_->LoadCache();
+
+  if (!available_callback_.is_null()) {
+    available_callback_.Run(net::OK);
+    available_callback_.Reset();
+  }
 }
 
 void ShaderDiskCache::EntryComplete(void* entry) {