Refactor our SimpleIndex file format and serialization to use Pickle instead of the previously bugg…

net/disk_cache/simple/simple_entry_format.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_FORMAT_H_
+#define NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_FORMAT_H_
+

[Philippe, 2013/04/16 11:58:47]

Nit: extra blank line.

+
+#include "base/basictypes.h"
+#include "base/port.h"
+#include "net/base/net_export.h"
+
+namespace base {
+class Time;
+}
+
+namespace disk_cache {
+
+const uint64 kSimpleInitialMagicNumber = GG_UINT64_C(0xfcfb6d1ba7725c30);

[Philippe, 2013/04/16 11:58:47]

I believe this (and below) could result in multiple defined references on
certain tool chains.

If some client code uses the address of |kSimpleInitialMagicNumber| then
|kSimpleInitialMagicNumber| needs to reside in memory.
Which object file will it be stored in/what if two different compilation units
use it?

enum constants are a nice way to address this since they cannot be referenced
but 64 bit enums are not supported before C++11 unfortunately.

Does this magic number need to be 64 bits?

Or can you make these declarations extern and define the variables in
simple_entry_format.cc instead?

+
+// A file in the Simple cache consists of a SimpleFileHeader followed
+// by data.
+
+const uint32 kSimpleVersion = 1;
+
+static const int kSimpleEntryFileCount = 3;

[Philippe, 2013/04/16 11:58:47]

The 'static' here is confusing. This is a header file.

+
+struct NET_EXPORT_PRIVATE SimpleFileHeader {
+  SimpleFileHeader();
+  uint64 initial_magic_number;
+  uint32 version;
+  uint32 key_length;
+  uint32 key_hash;
+};
+
+}  // namespace disk_cache
+
+#endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_FORMAT_H_