net/disk_cache/memory/mem_rankings.cc

   1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/disk_cache/memory/mem_rankings.h"
   6
   7 #include "base/logging.h"
   8 #include "net/disk_cache/memory/mem_entry_impl.h"
   9
  10 namespace disk_cache {
  11
  12 MemRankings::~MemRankings() {
  13   DCHECK(!head_ && !tail_);
  14 }
  15
  16 void MemRankings::Insert(MemEntryImpl* node) {
  17   if (head_)
  18     head_->set_prev(node);
  19
  20   if (!tail_)
  21     tail_ = node;
  22
  23   node->set_prev(NULL);
  24   node->set_next(head_);
  25   head_ = node;
  26 }
  27
  28 void MemRankings::Remove(MemEntryImpl* node) {
  29   MemEntryImpl* prev = node->prev();
  30   MemEntryImpl* next = node->next();
  31
  32   if (head_ == node)
  33     head_ = next;
  34
  35   if (tail_ == node)
  36     tail_ = prev;
  37
  38   if (prev)
  39     prev->set_next(next);
  40
  41   if (next)
  42     next->set_prev(prev);
  43
  44   node->set_next(NULL);
  45   node->set_prev(NULL);
  46 }
  47
  48 void MemRankings::UpdateRank(MemEntryImpl* node) {
  49   Remove(node);
  50   Insert(node);
  51 }
  52
  53 MemEntryImpl* MemRankings::GetNext(MemEntryImpl* node) {
  54   if (!node)
  55     return head_;
  56
  57   return node->next();
  58 }
  59
  60 MemEntryImpl* MemRankings::GetPrev(MemEntryImpl* node) {
  61   if (!node)
  62     return tail_;
  63
  64   return node->prev();
  65 }
  66
  67 }  // namespace disk_cache