Index: net/disk_cache/disk_format.h |
diff --git a/net/disk_cache/disk_format.h b/net/disk_cache/disk_format.h |
deleted file mode 100644 |
index 5d7597ab17d5c4c6e78c999b9ba02fd33cfb04f7..0000000000000000000000000000000000000000 |
--- a/net/disk_cache/disk_format.h |
+++ /dev/null |
@@ -1,153 +0,0 @@ |
-// Copyright (c) 2011 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. |
- |
-// The cache is stored on disk as a collection of block-files, plus an index |
-// file plus a collection of external files. |
-// |
-// Any data blob bigger than kMaxBlockSize (disk_cache/addr.h) will be stored in |
-// a separate file named f_xxx where x is a hexadecimal number. Shorter data |
-// will be stored as a series of blocks on a block-file. In any case, CacheAddr |
-// represents the address of the data inside the cache. |
-// |
-// The index file is just a simple hash table that maps a particular entry to |
-// a CacheAddr value. Linking for a given hash bucket is handled internally |
-// by the cache entry. |
-// |
-// The last element of the cache is the block-file. A block file is a file |
-// designed to store blocks of data of a given size. For more details see |
-// disk_cache/disk_format_base.h |
-// |
-// A new cache is initialized with four block files (named data_0 through |
-// data_3), each one dedicated to store blocks of a given size. The number at |
-// the end of the file name is the block file number (in decimal). |
-// |
-// There are two "special" types of blocks: an entry and a rankings node. An |
-// entry keeps track of all the information related to the same cache entry, |
-// such as the key, hash value, data pointers etc. A rankings node keeps track |
-// of the information that is updated frequently for a given entry, such as its |
-// location on the LRU lists, last access time etc. |
-// |
-// The files that store internal information for the cache (blocks and index) |
-// are at least partially memory mapped. They have a location that is signaled |
-// every time the internal structures are modified, so it is possible to detect |
-// (most of the time) when the process dies in the middle of an update. |
-// |
-// In order to prevent dirty data to be used as valid (after a crash), every |
-// cache entry has a dirty identifier. Each running instance of the cache keeps |
-// a separate identifier (maintained on the "this_id" header field) that is used |
-// to mark every entry that is created or modified. When the entry is closed, |
-// and all the data can be trusted, the dirty flag is cleared from the entry. |
-// When the cache encounters an entry whose identifier is different than the one |
-// being currently used, it means that the entry was not properly closed on a |
-// previous run, so it is discarded. |
- |
-#ifndef NET_DISK_CACHE_DISK_FORMAT_H_ |
-#define NET_DISK_CACHE_DISK_FORMAT_H_ |
- |
-#include "base/basictypes.h" |
-#include "net/base/net_export.h" |
-#include "net/disk_cache/disk_format_base.h" |
- |
-namespace disk_cache { |
- |
-const int kIndexTablesize = 0x10000; |
-const uint32 kIndexMagic = 0xC103CAC3; |
-const uint32 kCurrentVersion = 0x20000; // Version 2.0. |
- |
-struct LruData { |
- int32 pad1[2]; |
- int32 filled; // Flag to tell when we filled the cache. |
- int32 sizes[5]; |
- CacheAddr heads[5]; |
- CacheAddr tails[5]; |
- CacheAddr transaction; // In-flight operation target. |
- int32 operation; // Actual in-flight operation. |
- int32 operation_list; // In-flight operation list. |
- int32 pad2[7]; |
-}; |
- |
-// Header for the master index file. |
-struct NET_EXPORT_PRIVATE IndexHeader { |
- IndexHeader(); |
- |
- uint32 magic; |
- uint32 version; |
- int32 num_entries; // Number of entries currently stored. |
- int32 num_bytes; // Total size of the stored data. |
- int32 last_file; // Last external file created. |
- int32 this_id; // Id for all entries being changed (dirty flag). |
- CacheAddr stats; // Storage for usage data. |
- int32 table_len; // Actual size of the table (0 == kIndexTablesize). |
- int32 crash; // Signals a previous crash. |
- int32 experiment; // Id of an ongoing test. |
- uint64 create_time; // Creation time for this set of files. |
- int32 pad[52]; |
- LruData lru; // Eviction control data. |
-}; |
- |
-// The structure of the whole index file. |
-struct Index { |
- IndexHeader header; |
- CacheAddr table[kIndexTablesize]; // Default size. Actual size controlled |
- // by header.table_len. |
-}; |
- |
-// Main structure for an entry on the backing storage. If the key is longer than |
-// what can be stored on this structure, it will be extended on consecutive |
-// blocks (adding 256 bytes each time), up to 4 blocks (1024 - 32 - 1 chars). |
-// After that point, the whole key will be stored as a data block or external |
-// file. |
-struct EntryStore { |
- uint32 hash; // Full hash of the key. |
- CacheAddr next; // Next entry with the same hash or bucket. |
- CacheAddr rankings_node; // Rankings node for this entry. |
- int32 reuse_count; // How often is this entry used. |
- int32 refetch_count; // How often is this fetched from the net. |
- int32 state; // Current state. |
- uint64 creation_time; |
- int32 key_len; |
- CacheAddr long_key; // Optional address of a long key. |
- int32 data_size[4]; // We can store up to 4 data streams for each |
- CacheAddr data_addr[4]; // entry. |
- uint32 flags; // Any combination of EntryFlags. |
- int32 pad[4]; |
- uint32 self_hash; // The hash of EntryStore up to this point. |
- char key[256 - 24 * 4]; // null terminated |
-}; |
- |
-COMPILE_ASSERT(sizeof(EntryStore) == 256, bad_EntyStore); |
-const int kMaxInternalKeyLength = 4 * sizeof(EntryStore) - |
- offsetof(EntryStore, key) - 1; |
- |
-// Possible states for a given entry. |
-enum EntryState { |
- ENTRY_NORMAL = 0, |
- ENTRY_EVICTED, // The entry was recently evicted from the cache. |
- ENTRY_DOOMED // The entry was doomed. |
-}; |
- |
-// Flags that can be applied to an entry. |
-enum EntryFlags { |
- PARENT_ENTRY = 1, // This entry has children (sparse) entries. |
- CHILD_ENTRY = 1 << 1 // Child entry that stores sparse data. |
-}; |
- |
-#pragma pack(push, 4) |
-// Rankings information for a given entry. |
-struct RankingsNode { |
- uint64 last_used; // LRU info. |
- uint64 last_modified; // LRU info. |
- CacheAddr next; // LRU list. |
- CacheAddr prev; // LRU list. |
- CacheAddr contents; // Address of the EntryStore. |
- int32 dirty; // The entry is being modifyied. |
- uint32 self_hash; // RankingsNode's hash. |
-}; |
-#pragma pack(pop) |
- |
-COMPILE_ASSERT(sizeof(RankingsNode) == 36, bad_RankingsNode); |
- |
-} // namespace disk_cache |
- |
-#endif // NET_DISK_CACHE_DISK_FORMAT_H_ |