Disk cache: Update Addr to handle file format version 3.

net/disk_cache/addr.h

Index: net/disk_cache/addr.h
===================================================================
--- net/disk_cache/addr.h	(revision 205902)
+++ net/disk_cache/addr.h	(working copy)
@@ -16,15 +16,19 @@
 enum FileType {
   EXTERNAL = 0,
   RANKINGS = 1,
-  BLOCK_256,
-  BLOCK_1K,
-  BLOCK_4K,
+  BLOCK_256 = 2,
+  BLOCK_1K = 3,
+  BLOCK_4K = 4,
+  BLOCK_FILES = 5,
+  BLOCK_ENTRIES = 6,
+  BLOCK_EVICTED = 7
 };
 
 const int kMaxBlockSize = 4096 * 4;
 const int kMaxBlockFile = 255;
 const int kMaxNumBlocks = 4;
 const int kFirstAdditionalBlockFile = 4;
+const int kFirstAdditionalBlockFileV3 = 7;
 
 // Defines a storage address for a cache record
 //
@@ -38,6 +42,9 @@
 //   2 = 256 byte block file
 //   3 = 1k byte block file
 //   4 = 4k byte block file
+//   5 = external files block file
+//   6 = active entries block file
+//   7 = evicted entries block file
 //
 // If separate file:
 //   0000 1111 1111 1111 1111 1111 1111 1111 : file#  0 - 268,435,456 (2^28)
@@ -101,6 +108,19 @@
     return value_ != other.value_;
   }
 
+  // Conversions between the address of an external file and the address of the
+  // control block of that external file.
+  Addr AsExternal() const;
+  Addr AsBlockFile() const;
+
+  static Addr FromEntryAddress(uint32 value) {
+    return Addr(((8 + BLOCK_ENTRIES) << kFileTypeOffset) + value);

[gavinp, 2013/06/13 13:10:58]

8?

[rvargas (doing something else), 2013/06/13 19:07:25]

Rewrote it on a more explicit way.

+  }
+
+  static Addr FromEvictedAddress(uint32 value) {
+    return Addr(((8 + BLOCK_EVICTED) << kFileTypeOffset) + value);
+  }
+
   static int BlockSizeForFileType(FileType file_type) {
     switch (file_type) {
       case RANKINGS:
@@ -111,6 +131,12 @@
         return 1024;
       case BLOCK_4K:
         return 4096;
+      case BLOCK_FILES:
+        return 8;
+      case BLOCK_ENTRIES:
+        return 104;

[gavinp, 2013/06/13 13:10:58]

These magic numbers are killing me. Why 104?

[rvargas (doing something else), 2013/06/13 19:07:25]

Because there is a COMPILE_ASSERT(sizeof(EntryRecord) == 104) at line 172 of the
file format definition, and BLOCK_ENTRIES is the file that stores regular
entries (aka, entry records).

Sure, this could be sizeof() (at the cost of a cast), but that means that this
file would have to include v3/disk_format_.h, but it only includes
disk_format_base because it is used by both v2 and v3, and there is no way to
include both definitions on a single compilation unit.

+      case BLOCK_EVICTED:
+        return 48;
       default:
         return 0;
     }
@@ -133,8 +159,10 @@
   }
 
   // Returns true if this address looks like a valid one.
-  bool SanityCheck() const;
+  bool SanityCheckV2() const;
+  bool SanityCheckV3() const;
   bool SanityCheckForEntryV2() const;
+  bool SanityCheckForEntryV3() const;
   bool SanityCheckForRankings() const;
 
  private: