SimpleCache: merge the first and second stream in one file

net/disk_cache/simple/simple_entry_format.h

Index: net/disk_cache/simple/simple_entry_format.h
diff --git a/net/disk_cache/simple/simple_entry_format.h b/net/disk_cache/simple/simple_entry_format.h
index d06ab1139c53980c54a50347c0bb36279d6a3f28..ac3f55dfa88fef1a18f94ee3cf50b374a2ad8712 100644
--- a/net/disk_cache/simple/simple_entry_format.h
+++ b/net/disk_cache/simple/simple_entry_format.h
@@ -19,17 +19,23 @@ namespace disk_cache {
 const uint64 kSimpleInitialMagicNumber = GG_UINT64_C(0xfcfb6d1ba7725c30);
 const uint64 kSimpleFinalMagicNumber = GG_UINT64_C(0xf4fa6f45970d41d8);
 
-// A file in the Simple cache consists of a SimpleFileHeader followed
-// by data.
+// A file containing stream 0 and stream 1 in the Simple cache consists of:
+//   - a SimpleFileHeader.
+//   - the key.
+//   - the data from stream 1.
+//   - a SimpleFileEOF record for stream 1.
+//   - the data from stream 0.
+//   - a SimpleFileEOF record for stream 0.
 
-// A file in the Simple cache consists of:
+// A file containing stream 2 in the Simple cache consists of:
 //   - a SimpleFileHeader.
 //   - the key.
 //   - the data.
 //   - at the end, a SimpleFileEOF record.
-const uint32 kSimpleVersion = 4;
+const uint32 kSimpleVersion = 5;
 
-static const int kSimpleEntryFileCount = 3;
+static const int kSimpleEntryFileCount = 2;
+static const int kSimpleEntryStreamCount = 3;
 
 struct NET_EXPORT_PRIVATE SimpleFileHeader {
   SimpleFileHeader();
@@ -50,6 +56,8 @@ struct SimpleFileEOF {
   uint64 final_magic_number;
   uint32 flags;
   uint32 data_crc32;
+  // |stream_size| is only used in the EOF record for stream 0.
+  uint32 stream_size;

[gavinp, 2013/09/17 15:07:43]

This probably is adding another 32 bits of padding, but that's OK, since we
memset this whole struct to 0 in the constructor for precisely this reason.

 };
 
 }  // namespace disk_cache