SimpleCache: synchronously reply on reads from idle if data is in memory.

net/disk_cache/simple/simple_entry_impl.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_IMPL_H_
 #define NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_IMPL_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 177 matching lines @@
   void OpenEntryInternal(bool have_index,
                          const CompletionCallback& callback,
                          Entry** out_entry);
 
   void CreateEntryInternal(bool have_index,
                            const CompletionCallback& callback,
                            Entry** out_entry);
 
   void CloseInternal();
 
-  void ReadDataInternal(int index,
-                        int offset,
-                        net::IOBuffer* buf,
-                        int buf_len,
-                        const CompletionCallback& callback);
+  int ReadDataInternal(bool sync_possible,
+                       int index,
+                       int offset,
+                       net::IOBuffer* buf,
+                       int buf_len,
+                       const CompletionCallback& callback);
 
   void WriteDataInternal(int index,
                          int offset,
                          net::IOBuffer* buf,
                          int buf_len,
                          const CompletionCallback& callback,
                          bool truncate);
 
   void ReadSparseDataInternal(int64_t sparse_offset,
                               net::IOBuffer* buf,
@@ skipping 85 matching lines @@
   // operations.
   void UpdateDataFromEntryStat(const SimpleEntryStat& entry_stat);
 
   int64_t GetDiskUsage() const;
 
   // Used to report histograms.
   void RecordReadIsParallelizable(const SimpleEntryOperation& operation) const;
   void RecordWriteDependencyType(const SimpleEntryOperation& operation) const;
 
   // Completes a read from the stream data kept in memory, logging metrics
-  // and updating metadata. If |callback| is non-null, it will be posted to the
-  // current task runner with the return code.
-  void ReadFromBufferAndPostReply(net::GrowableIOBuffer* in_buf,
-                                  int offset,
-                                  int buf_len,
-                                  net::IOBuffer* out_buf,
-                                  const CompletionCallback& callback);
+  // and updating metadata. Returns the # of bytes read successfully.
+  // This asumes the caller has already range-checked offset and buf_len
+  // appropriately.
+  int ReadFromBuffer(net::GrowableIOBuffer* in_buf,
+                     int offset,
+                     int buf_len,
+                     net::IOBuffer* out_buf);
 
   // Copies data from |buf| to the internal in-memory buffer for stream 0. If
   // |truncate| is set to true, the target buffer will be truncated at |offset|
   // + |buf_len| before being written.
   int SetStream0Data(net::IOBuffer* buf,
                      int offset, int buf_len,
                      bool truncate);
 
   // Updates |crc32s_| and |crc32s_end_offset_| for a write of the data in
   // |buffer| on |stream_index|, starting at |offset| and of length |length|.
@@ skipping 83 matching lines @@
 
   // Sometimes stream 1 data is prefetched when stream 0 is first read.
   // If a write to the stream occurs on the entry the prefetch buffer is
   // discarded. It may also be null if it wasn't prefetched in the first place.
   scoped_refptr<net::GrowableIOBuffer> stream_1_prefetch_data_;
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_IMPL_H_