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Side by Side Diff: net/disk_cache/flash/segment.cc

Issue 182093002: Remove the flash specific disk cache backend. (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: Created 6 years, 10 months ago
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1 // Copyright (c) 2012 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 <algorithm>
6
7 #include "base/logging.h"
8 #include "net/disk_cache/flash/format.h"
9 #include "net/disk_cache/flash/segment.h"
10 #include "net/disk_cache/flash/storage.h"
11
12 namespace disk_cache {
13
14 Segment::Segment(int32 index, bool read_only, Storage* storage)
15 : index_(index),
16 num_users_(0),
17 read_only_(read_only),
18 init_(false),
19 storage_(storage),
20 offset_(index * kFlashSegmentSize),
21 summary_offset_(offset_ + kFlashSegmentSize - kFlashSummarySize),
22 write_offset_(offset_) {
23 DCHECK(storage);
24 DCHECK(storage->size() % kFlashSegmentSize == 0);
25 }
26
27 Segment::~Segment() {
28 DCHECK(!init_ || read_only_);
29 if (num_users_ != 0)
30 LOG(WARNING) << "Users exist, but we don't care? " << num_users_;
31 }
32
33 bool Segment::HaveOffset(int32 offset) const {
34 DCHECK(init_);
35 return std::binary_search(offsets_.begin(), offsets_.end(), offset);
36 }
37
38 void Segment::AddUser() {
39 DCHECK(init_);
40 ++num_users_;
41 }
42
43 void Segment::ReleaseUser() {
44 DCHECK(init_);
45 --num_users_;
46 }
47
48 bool Segment::HasNoUsers() const {
49 DCHECK(init_);
50 return num_users_ == 0;
51 }
52
53 bool Segment::Init() {
54 DCHECK(!init_);
55
56 if (offset_ < 0 || offset_ + kFlashSegmentSize > storage_->size())
57 return false;
58
59 if (!read_only_) {
60 init_ = true;
61 return true;
62 }
63
64 int32 summary[kFlashMaxEntryCount + 1];
65 if (!storage_->Read(summary, kFlashSummarySize, summary_offset_))
66 return false;
67
68 size_t entry_count = summary[0];
69 DCHECK_LE(entry_count, kFlashMaxEntryCount);
70
71 std::vector<int32> tmp(summary + 1, summary + 1 + entry_count);
72 offsets_.swap(tmp);
73 init_ = true;
74 return true;
75 }
76
77 bool Segment::WriteData(const void* buffer, int32 size) {
78 DCHECK(init_ && !read_only_);
79 DCHECK(write_offset_ + size <= summary_offset_);
80 if (!storage_->Write(buffer, size, write_offset_))
81 return false;
82 write_offset_ += size;
83 return true;
84 }
85
86 void Segment::StoreOffset(int32 offset) {
87 DCHECK(init_ && !read_only_);
88 DCHECK(offsets_.size() < kFlashMaxEntryCount);
89 offsets_.push_back(offset);
90 }
91
92 bool Segment::ReadData(void* buffer, int32 size, int32 offset) const {
93 DCHECK(init_);
94 DCHECK(offset >= offset_ && offset + size <= offset_ + kFlashSegmentSize);
95 return storage_->Read(buffer, size, offset);
96 }
97
98 bool Segment::Close() {
99 DCHECK(init_);
100 if (read_only_)
101 return true;
102
103 DCHECK(offsets_.size() <= kFlashMaxEntryCount);
104
105 int32 summary[kFlashMaxEntryCount + 1];
106 memset(summary, 0, kFlashSummarySize);
107 summary[0] = offsets_.size();
108 std::copy(offsets_.begin(), offsets_.end(), summary + 1);
109 if (!storage_->Write(summary, kFlashSummarySize, summary_offset_))
110 return false;
111
112 read_only_ = true;
113 return true;
114 }
115
116 bool Segment::CanHold(int32 size) const {
117 DCHECK(init_);
118 return offsets_.size() < kFlashMaxEntryCount &&
119 write_offset_ + size <= summary_offset_;
120 }
121
122 } // namespace disk_cache
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