Disk cache: Add a histogram to measure the latency of...

net/disk_cache/entry_impl.h

 // Copyright (c) 2006-2009 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_ENTRY_IMPL_H_
 #define NET_DISK_CACHE_ENTRY_IMPL_H_
 
 #include "base/scoped_ptr.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/storage_block.h"
 #include "net/disk_cache/storage_block-inl.h"
 
 namespace disk_cache {
 
 class BackendImpl;
 class SparseControl;
 
 // This class implements the Entry interface. An object of this
 // class represents a single entry on the cache.
 class EntryImpl : public Entry, public base::RefCounted<EntryImpl> {
   friend class base::RefCounted<EntryImpl>;
   friend class SparseControl;
  public:
+  enum Operation {

[darin (slow to review), 2009/08/28 23:14:37]

nit: though kFoo is encouraged by the style guide, we have been trying to stick
with the old MACRO_STYLE rule for enum names.  (This is in the chrome style
guide.)

+    kRead,
+    kWrite,
+    kSparseRead,
+    kSparseWrite,
+    kAsyncIO
+  };
+
   EntryImpl(BackendImpl* backend, Addr address);
 
   // Entry interface.
   virtual void Doom();
   virtual void Close();
   virtual std::string GetKey() const;
   virtual base::Time GetLastUsed() const;
   virtual base::Time GetLastModified() const;
   virtual int32 GetDataSize(int index) const;
   virtual int ReadData(int index, int offset, net::IOBuffer* buf, int buf_len,
@@ skipping 58 matching lines @@
   bool SanityCheck();
 
   // Handle the pending asynchronous IO count.
   void IncrementIoCount();
   void DecrementIoCount();
 
   // Set the access times for this entry. This method provides support for
   // the upgrade tool.
   void SetTimes(base::Time last_used, base::Time last_modified);
 
+  // Generates a histogram for the time spent working on this operation.
+  void ReportIOTime(Operation op, const base::Time& start);
+
  private:
   enum {
      kNumStreams = 3
   };
 
-  enum Operation {
-    kRead,
-    kWrite,
-    kSparseRead,
-    kSparseWrite
-  };
-
   ~EntryImpl();
 
   // Initializes the storage for an internal or external data block.
   bool CreateDataBlock(int index, int size);
 
   // Initializes the storage for an internal or external generic block.
   bool CreateBlock(int size, Addr* address);
 
   // Deletes the data pointed by address, maybe backed by files_[index].
   void DeleteData(Addr address, int index);
@@ skipping 35 matching lines @@
   // Gets the data stored at the given index. If the information is in memory,
   // a buffer will be allocated and the data will be copied to it (the caller
   // can find out the size of the buffer before making this call). Otherwise,
   // the cache address of the data will be returned, and that address will be
   // removed from the regular book keeping of this entry so the caller is
   // responsible for deleting the block (or file) from the backing store at some
   // point; there is no need to report any storage-size change, only to do the
   // actual cleanup.
   void GetData(int index, char** buffer, Addr* address);
 
-  // Generates a histogram for the time spent working on this operation.
-  void ReportIOTime(Operation op, const base::Time& start);
-
   // Logs this entry to the internal trace buffer.
   void Log(const char* msg);
 
   CacheEntryBlock entry_;     // Key related information for this entry.
   CacheRankingsBlock node_;   // Rankings related information for this entry.
   BackendImpl* backend_;      // Back pointer to the cache.
   scoped_array<char> user_buffers_[kNumStreams];  // Store user data.
   // Files to store external user data and key.
   scoped_refptr<File> files_[kNumStreams + 1];
   // Copy of the file used to store the key. We don't own this object.
   mutable File* key_file_;
   int unreported_size_[kNumStreams];  // Bytes not reported yet to the backend.
   bool doomed_;               // True if this entry was removed from the cache.
   scoped_ptr<SparseControl> sparse_;  // Support for sparse entries.
 
   DISALLOW_EVIL_CONSTRUCTORS(EntryImpl);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_ENTRY_IMPL_H_