Disk cache: Implement request throttling.

Note that no throttling is performed with this change,
the backend is not activating the feature.

BUG=54338
TEST=none.


Review URL: http://codereview.chromium.org/3416002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@59437 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 14 insertions, 3 deletions

diff --git a/net/disk_cache/in_flight_backend_io.h b/net/disk_cache/in_flight_backend_io.h
index 083c6fd..213c261 100644
--- a/net/disk_cache/in_flight_backend_io.h
+++ b/net/disk_cache/in_flight_backend_io.h
@@ -39,6 +39,9 @@ class BackendIO : public BackgroundIO {
 
   void ReleaseEntry();
 
+  // Returns the time that has passed since the operation was created.
+  base::TimeDelta ElapsedTime() const;
+
   // The operations we proxy:
   void Init();
   void OpenEntry(const std::string& key, Entry** entry);
@@ -124,6 +127,7 @@ class BackendIO : public BackgroundIO {
   bool truncate_;
   int64 offset64_;
   int64* start_;
+  base::TimeTicks start_time_;
 
   DISALLOW_COPY_AND_ASSIGN(BackendIO);
 };
@@ -132,9 +136,8 @@ class BackendIO : public BackgroundIO {
 class InFlightBackendIO : public InFlightIO {
  public:
   InFlightBackendIO(BackendImpl* backend,
-                    base::MessageLoopProxy* background_thread)
-      : backend_(backend), background_thread_(background_thread) {}
-  ~InFlightBackendIO() {}
+                    base::MessageLoopProxy* background_thread);
+  ~InFlightBackendIO();
 
   // The operations we proxy:
   void Init(net::CompletionCallback* callback);
@@ -182,6 +185,10 @@ class InFlightBackendIO : public InFlightIO {
     return background_thread_->BelongsToCurrentThread();
   }
 
+  // Controls the queing of entry (async) operations.
+  void StartQueingOperations();
+  void StopQueingOperations();
+
  protected:
   virtual void OnOperationComplete(BackgroundIO* operation, bool cancel);
 
@@ -189,10 +196,14 @@ class InFlightBackendIO : public InFlightIO {
   typedef std::list<scoped_refptr<BackendIO> > OperationList;
   void QueueOperation(BackendIO* operation);
   void PostOperation(BackendIO* operation);
+  void PostQueuedOperation(OperationList* from_list);
+  void QueueOperationToList(BackendIO* operation, OperationList* list);
 
   BackendImpl* backend_;
   scoped_refptr<base::MessageLoopProxy> background_thread_;
   OperationList pending_ops_;  // The list of operations to be posted.
+  OperationList pending_entry_ops_;  // Entry (async) operations to be posted.
+  bool queue_entry_ops_;  // True if we are queuing entry (async) operations.
 
   DISALLOW_COPY_AND_ASSIGN(InFlightBackendIO);
 };