OLD | NEW |
| (Empty) |
1 /* | |
2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. | |
3 * | |
4 * Use of this source code is governed by a BSD-style license | |
5 * that can be found in the LICENSE file in the root of the source | |
6 * tree. An additional intellectual property rights grant can be found | |
7 * in the file PATENTS. All contributing project authors may | |
8 * be found in the AUTHORS file in the root of the source tree. | |
9 */ | |
10 | |
11 #include <time.h> | |
12 | |
13 #if defined(WEBRTC_WIN) | |
14 #include "webrtc/base/win32.h" | |
15 #endif | |
16 | |
17 #include <algorithm> | |
18 #include <memory> | |
19 | |
20 #include "webrtc/base/arraysize.h" | |
21 #include "webrtc/base/checks.h" | |
22 #include "webrtc/base/diskcache.h" | |
23 #include "webrtc/base/fileutils.h" | |
24 #include "webrtc/base/pathutils.h" | |
25 #include "webrtc/base/stream.h" | |
26 #include "webrtc/base/stringencode.h" | |
27 #include "webrtc/base/stringutils.h" | |
28 | |
29 #define TRANSPARENT_CACHE_NAMES RTC_DCHECK_IS_ON | |
30 | |
31 namespace rtc { | |
32 | |
33 class DiskCache; | |
34 | |
35 /////////////////////////////////////////////////////////////////////////////// | |
36 // DiskCacheAdapter | |
37 /////////////////////////////////////////////////////////////////////////////// | |
38 | |
39 class DiskCacheAdapter : public StreamAdapterInterface { | |
40 public: | |
41 DiskCacheAdapter(const DiskCache* cache, const std::string& id, size_t index, | |
42 StreamInterface* stream) | |
43 : StreamAdapterInterface(stream), cache_(cache), id_(id), index_(index) | |
44 { } | |
45 ~DiskCacheAdapter() override { | |
46 Close(); | |
47 cache_->ReleaseResource(id_, index_); | |
48 } | |
49 | |
50 private: | |
51 const DiskCache* cache_; | |
52 std::string id_; | |
53 size_t index_; | |
54 }; | |
55 | |
56 /////////////////////////////////////////////////////////////////////////////// | |
57 // DiskCache | |
58 /////////////////////////////////////////////////////////////////////////////// | |
59 | |
60 DiskCache::DiskCache() : max_cache_(0), total_size_(0), total_accessors_(0) { | |
61 } | |
62 | |
63 DiskCache::~DiskCache() { | |
64 RTC_DCHECK(0 == total_accessors_); | |
65 } | |
66 | |
67 bool DiskCache::Initialize(const std::string& folder, size_t size) { | |
68 if (!folder_.empty() || !Filesystem::CreateFolder(folder)) | |
69 return false; | |
70 | |
71 folder_ = folder; | |
72 max_cache_ = size; | |
73 RTC_DCHECK(0 == total_size_); | |
74 | |
75 if (!InitializeEntries()) | |
76 return false; | |
77 | |
78 return CheckLimit(); | |
79 } | |
80 | |
81 bool DiskCache::Purge() { | |
82 if (folder_.empty()) | |
83 return false; | |
84 | |
85 if (total_accessors_ > 0) { | |
86 LOG_F(LS_WARNING) << "Cache files open"; | |
87 return false; | |
88 } | |
89 | |
90 if (!PurgeFiles()) | |
91 return false; | |
92 | |
93 map_.clear(); | |
94 return true; | |
95 } | |
96 | |
97 bool DiskCache::LockResource(const std::string& id) { | |
98 Entry* entry = GetOrCreateEntry(id, true); | |
99 if (LS_LOCKED == entry->lock_state) | |
100 return false; | |
101 if ((LS_UNLOCKED == entry->lock_state) && (entry->accessors > 0)) | |
102 return false; | |
103 if ((total_size_ > max_cache_) && !CheckLimit()) { | |
104 LOG_F(LS_WARNING) << "Cache overfull"; | |
105 return false; | |
106 } | |
107 entry->lock_state = LS_LOCKED; | |
108 return true; | |
109 } | |
110 | |
111 StreamInterface* DiskCache::WriteResource(const std::string& id, size_t index) { | |
112 Entry* entry = GetOrCreateEntry(id, false); | |
113 if (LS_LOCKED != entry->lock_state) | |
114 return NULL; | |
115 | |
116 size_t previous_size = 0; | |
117 std::string filename(IdToFilename(id, index)); | |
118 FileStream::GetSize(filename, &previous_size); | |
119 RTC_DCHECK(previous_size <= entry->size); | |
120 if (previous_size > entry->size) { | |
121 previous_size = entry->size; | |
122 } | |
123 | |
124 std::unique_ptr<FileStream> file(new FileStream); | |
125 if (!file->Open(filename, "wb", NULL)) { | |
126 LOG_F(LS_ERROR) << "Couldn't create cache file"; | |
127 return NULL; | |
128 } | |
129 | |
130 entry->streams = std::max(entry->streams, index + 1); | |
131 entry->size -= previous_size; | |
132 total_size_ -= previous_size; | |
133 | |
134 entry->accessors += 1; | |
135 total_accessors_ += 1; | |
136 return new DiskCacheAdapter(this, id, index, file.release()); | |
137 } | |
138 | |
139 bool DiskCache::UnlockResource(const std::string& id) { | |
140 Entry* entry = GetOrCreateEntry(id, false); | |
141 if (LS_LOCKED != entry->lock_state) | |
142 return false; | |
143 | |
144 if (entry->accessors > 0) { | |
145 entry->lock_state = LS_UNLOCKING; | |
146 } else { | |
147 entry->lock_state = LS_UNLOCKED; | |
148 entry->last_modified = time(0); | |
149 CheckLimit(); | |
150 } | |
151 return true; | |
152 } | |
153 | |
154 StreamInterface* DiskCache::ReadResource(const std::string& id, | |
155 size_t index) const { | |
156 const Entry* entry = GetEntry(id); | |
157 if (LS_UNLOCKED != entry->lock_state) | |
158 return NULL; | |
159 if (index >= entry->streams) | |
160 return NULL; | |
161 | |
162 std::unique_ptr<FileStream> file(new FileStream); | |
163 if (!file->Open(IdToFilename(id, index), "rb", NULL)) | |
164 return NULL; | |
165 | |
166 entry->accessors += 1; | |
167 total_accessors_ += 1; | |
168 return new DiskCacheAdapter(this, id, index, file.release()); | |
169 } | |
170 | |
171 bool DiskCache::HasResource(const std::string& id) const { | |
172 const Entry* entry = GetEntry(id); | |
173 return (NULL != entry) && (entry->streams > 0); | |
174 } | |
175 | |
176 bool DiskCache::HasResourceStream(const std::string& id, size_t index) const { | |
177 const Entry* entry = GetEntry(id); | |
178 if ((NULL == entry) || (index >= entry->streams)) | |
179 return false; | |
180 | |
181 std::string filename = IdToFilename(id, index); | |
182 | |
183 return FileExists(filename); | |
184 } | |
185 | |
186 bool DiskCache::DeleteResource(const std::string& id) { | |
187 Entry* entry = GetOrCreateEntry(id, false); | |
188 if (!entry) | |
189 return true; | |
190 | |
191 if ((LS_UNLOCKED != entry->lock_state) || (entry->accessors > 0)) | |
192 return false; | |
193 | |
194 bool success = true; | |
195 for (size_t index = 0; index < entry->streams; ++index) { | |
196 std::string filename = IdToFilename(id, index); | |
197 | |
198 if (!FileExists(filename)) | |
199 continue; | |
200 | |
201 if (!DeleteFile(filename)) { | |
202 LOG_F(LS_ERROR) << "Couldn't remove cache file: " << filename; | |
203 success = false; | |
204 } | |
205 } | |
206 | |
207 total_size_ -= entry->size; | |
208 map_.erase(id); | |
209 return success; | |
210 } | |
211 | |
212 bool DiskCache::CheckLimit() { | |
213 #if RTC_DCHECK_IS_ON | |
214 // Temporary check to make sure everything is working correctly. | |
215 size_t cache_size = 0; | |
216 for (EntryMap::iterator it = map_.begin(); it != map_.end(); ++it) { | |
217 cache_size += it->second.size; | |
218 } | |
219 RTC_DCHECK(cache_size == total_size_); | |
220 #endif | |
221 | |
222 // TODO: Replace this with a non-brain-dead algorithm for clearing out the | |
223 // oldest resources... something that isn't O(n^2) | |
224 while (total_size_ > max_cache_) { | |
225 EntryMap::iterator oldest = map_.end(); | |
226 for (EntryMap::iterator it = map_.begin(); it != map_.end(); ++it) { | |
227 if ((LS_UNLOCKED != it->second.lock_state) || (it->second.accessors > 0)) | |
228 continue; | |
229 oldest = it; | |
230 break; | |
231 } | |
232 if (oldest == map_.end()) { | |
233 LOG_F(LS_WARNING) << "All resources are locked!"; | |
234 return false; | |
235 } | |
236 for (EntryMap::iterator it = oldest++; it != map_.end(); ++it) { | |
237 if (it->second.last_modified < oldest->second.last_modified) { | |
238 oldest = it; | |
239 } | |
240 } | |
241 if (!DeleteResource(oldest->first)) { | |
242 LOG_F(LS_ERROR) << "Couldn't delete from cache!"; | |
243 return false; | |
244 } | |
245 } | |
246 return true; | |
247 } | |
248 | |
249 std::string DiskCache::IdToFilename(const std::string& id, size_t index) const { | |
250 #ifdef TRANSPARENT_CACHE_NAMES | |
251 // This escapes colons and other filesystem characters, so the user can't open | |
252 // special devices (like "COM1:"), or access other directories. | |
253 size_t buffer_size = id.length()*3 + 1; | |
254 char* buffer = new char[buffer_size]; | |
255 encode(buffer, buffer_size, id.data(), id.length(), | |
256 unsafe_filename_characters(), '%'); | |
257 // TODO(nisse): RTC_DCHECK(strlen(buffer) < FileSystem::MaxBasenameLength()); | |
258 #else // !TRANSPARENT_CACHE_NAMES | |
259 // We might want to just use a hash of the filename at some point, both for | |
260 // obfuscation, and to avoid both filename length and escaping issues. | |
261 RTC_NOTREACHED(); | |
262 #endif // !TRANSPARENT_CACHE_NAMES | |
263 | |
264 char extension[32]; | |
265 sprintfn(extension, arraysize(extension), ".%u", index); | |
266 | |
267 Pathname pathname; | |
268 pathname.SetFolder(folder_); | |
269 pathname.SetBasename(buffer); | |
270 pathname.SetExtension(extension); | |
271 | |
272 #ifdef TRANSPARENT_CACHE_NAMES | |
273 delete [] buffer; | |
274 #endif // TRANSPARENT_CACHE_NAMES | |
275 | |
276 return pathname.pathname(); | |
277 } | |
278 | |
279 bool DiskCache::FilenameToId(const std::string& filename, std::string* id, | |
280 size_t* index) const { | |
281 Pathname pathname(filename); | |
282 unsigned tempdex; | |
283 if (1 != sscanf(pathname.extension().c_str(), ".%u", &tempdex)) | |
284 return false; | |
285 | |
286 *index = static_cast<size_t>(tempdex); | |
287 | |
288 size_t buffer_size = pathname.basename().length() + 1; | |
289 char* buffer = new char[buffer_size]; | |
290 decode(buffer, buffer_size, pathname.basename().data(), | |
291 pathname.basename().length(), '%'); | |
292 id->assign(buffer); | |
293 delete [] buffer; | |
294 return true; | |
295 } | |
296 | |
297 DiskCache::Entry* DiskCache::GetOrCreateEntry(const std::string& id, | |
298 bool create) { | |
299 EntryMap::iterator it = map_.find(id); | |
300 if (it != map_.end()) | |
301 return &it->second; | |
302 if (!create) | |
303 return NULL; | |
304 Entry e; | |
305 e.lock_state = LS_UNLOCKED; | |
306 e.accessors = 0; | |
307 e.size = 0; | |
308 e.streams = 0; | |
309 e.last_modified = time(0); | |
310 it = map_.insert(EntryMap::value_type(id, e)).first; | |
311 return &it->second; | |
312 } | |
313 | |
314 void DiskCache::ReleaseResource(const std::string& id, size_t index) const { | |
315 const Entry* entry = GetEntry(id); | |
316 if (!entry) { | |
317 LOG_F(LS_WARNING) << "Missing cache entry"; | |
318 RTC_NOTREACHED(); | |
319 return; | |
320 } | |
321 | |
322 entry->accessors -= 1; | |
323 total_accessors_ -= 1; | |
324 | |
325 if (LS_UNLOCKED != entry->lock_state) { | |
326 // This is safe, because locked resources only issue WriteResource, which | |
327 // is non-const. Think about a better way to handle it. | |
328 DiskCache* this2 = const_cast<DiskCache*>(this); | |
329 Entry* entry2 = this2->GetOrCreateEntry(id, false); | |
330 | |
331 size_t new_size = 0; | |
332 std::string filename(IdToFilename(id, index)); | |
333 FileStream::GetSize(filename, &new_size); | |
334 entry2->size += new_size; | |
335 this2->total_size_ += new_size; | |
336 | |
337 if ((LS_UNLOCKING == entry->lock_state) && (0 == entry->accessors)) { | |
338 entry2->last_modified = time(0); | |
339 entry2->lock_state = LS_UNLOCKED; | |
340 this2->CheckLimit(); | |
341 } | |
342 } | |
343 } | |
344 | |
345 /////////////////////////////////////////////////////////////////////////////// | |
346 | |
347 } // namespace rtc | |
OLD | NEW |