Reorganize net/disk_cache into backend specific directories.

net/disk_cache/addr.h

-// Copyright (c) 2012 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.
-
-// This is an internal class that handles the address of a cache record.
-// See net/disk_cache/disk_cache.h for the public interface of the cache.
-
-#ifndef NET_DISK_CACHE_ADDR_H_
-#define NET_DISK_CACHE_ADDR_H_
-
-#include "net/base/net_export.h"
-#include "net/disk_cache/disk_format_base.h"
-
-namespace disk_cache {
-
-enum FileType {
-  EXTERNAL = 0,
-  RANKINGS = 1,
-  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
-//
-// Header:
-//   1000 0000 0000 0000 0000 0000 0000 0000 : initialized bit
-//   0111 0000 0000 0000 0000 0000 0000 0000 : file type
-//
-// File type values:
-//   0 = separate file on disk
-//   1 = rankings block file
-//   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)
-//
-// If block file:
-//   0000 1100 0000 0000 0000 0000 0000 0000 : reserved bits
-//   0000 0011 0000 0000 0000 0000 0000 0000 : number of contiguous blocks 1-4
-//   0000 0000 1111 1111 0000 0000 0000 0000 : file selector 0 - 255
-//   0000 0000 0000 0000 1111 1111 1111 1111 : block#  0 - 65,535 (2^16)
-//
-// Note that an Addr can be used to "point" to a variety of different objects,
-// from a given type of entry to random blobs of data. Conceptually, an Addr is
-// just a number that someone can inspect to find out how to locate the desired
-// record. Most users will not care about the specific bits inside Addr, for
-// example, what parts of it point to a file number; only the code that has to
-// select a specific file would care about those specific bits.
-//
-// From a general point of view, an Addr has a total capacity of 2^24 entities,
-// in that it has 24 bits that can identify individual records. Note that the
-// address space is bigger for independent files (2^28), but that would not be
-// the general case.
-class NET_EXPORT_PRIVATE Addr {
- public:
-  Addr() : value_(0) {}
-  explicit Addr(CacheAddr address) : value_(address) {}
-  Addr(FileType file_type, int max_blocks, int block_file, int index) {
-    value_ = ((file_type << kFileTypeOffset) & kFileTypeMask) |
-             (((max_blocks - 1) << kNumBlocksOffset) & kNumBlocksMask) |
-             ((block_file << kFileSelectorOffset) & kFileSelectorMask) |
-             (index  & kStartBlockMask) | kInitializedMask;
-  }
-
-  CacheAddr value() const { return value_; }
-  void set_value(CacheAddr address) {
-    value_ = address;
-  }
-
-  bool is_initialized() const {
-    return (value_ & kInitializedMask) != 0;
-  }
-
-  bool is_separate_file() const {
-    return (value_ & kFileTypeMask) == 0;
-  }
-
-  bool is_block_file() const {
-    return !is_separate_file();
-  }
-
-  FileType file_type() const {
-    return static_cast<FileType>((value_ & kFileTypeMask) >> kFileTypeOffset);
-  }
-
-  int FileNumber() const {
-    if (is_separate_file())
-      return value_ & kFileNameMask;
-    else
-      return ((value_ & kFileSelectorMask) >> kFileSelectorOffset);
-  }
-
-  int start_block() const;
-  int num_blocks() const;
-  bool SetFileNumber(int file_number);
-  int BlockSize() const {
-    return BlockSizeForFileType(file_type());
-  }
-
-  bool operator==(Addr other) const {
-    return value_ == other.value_;
-  }
-
-  bool operator!=(Addr other) const {
-    return value_ != other.value_;
-  }
-
-  static int BlockSizeForFileType(FileType file_type) {
-    switch (file_type) {
-      case RANKINGS:
-        return 36;
-      case BLOCK_256:
-        return 256;
-      case BLOCK_1K:
-        return 1024;
-      case BLOCK_4K:
-        return 4096;
-      case BLOCK_FILES:
-        return 8;
-      case BLOCK_ENTRIES:
-        return 104;
-      case BLOCK_EVICTED:
-        return 48;
-      default:
-        return 0;
-    }
-  }
-
-  static FileType RequiredFileType(int size) {
-    if (size < 1024)
-      return BLOCK_256;
-    else if (size < 4096)
-      return BLOCK_1K;
-    else if (size <= 4096 * 4)
-      return BLOCK_4K;
-    else
-      return EXTERNAL;
-  }
-
-  static int RequiredBlocks(int size, FileType file_type) {
-    int block_size = BlockSizeForFileType(file_type);
-    return (size + block_size - 1) / block_size;
-  }
-
-  // Returns true if this address looks like a valid one.
-  bool SanityCheckV2() const;
-  bool SanityCheckV3() const;
-  bool SanityCheckForEntryV2() const;
-  bool SanityCheckForEntryV3() const;
-  bool SanityCheckForRankings() const;
-
- private:
-  uint32 reserved_bits() const {
-    return value_ & kReservedBitsMask;
-  }
-
-  static const uint32 kInitializedMask    = 0x80000000;
-  static const uint32 kFileTypeMask       = 0x70000000;
-  static const uint32 kFileTypeOffset     = 28;
-  static const uint32 kReservedBitsMask   = 0x0c000000;
-  static const uint32 kNumBlocksMask      = 0x03000000;
-  static const uint32 kNumBlocksOffset    = 24;
-  static const uint32 kFileSelectorMask   = 0x00ff0000;
-  static const uint32 kFileSelectorOffset = 16;
-  static const uint32 kStartBlockMask     = 0x0000FFFF;
-  static const uint32 kFileNameMask       = 0x0FFFFFFF;
-
-  CacheAddr value_;
-};
-
-}  // namespace disk_cache
-
-#endif  // NET_DISK_CACHE_ADDR_H_