henrike@webrtc.org | 0e118e7 | 2013-07-10 00:45:36 +0000 | [diff] [blame] | 1 | /* |
| 2 | * libjingle |
| 3 | * Copyright 2004--2005, Google Inc. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions are met: |
| 7 | * |
| 8 | * 1. Redistributions of source code must retain the above copyright notice, |
| 9 | * this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright notice, |
| 11 | * this list of conditions and the following disclaimer in the documentation |
| 12 | * and/or other materials provided with the distribution. |
| 13 | * 3. The name of the author may not be used to endorse or promote products |
| 14 | * derived from this software without specific prior written permission. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| 17 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| 18 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
| 19 | * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 20 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 21 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| 22 | * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 23 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| 24 | * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| 25 | * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 | */ |
| 27 | |
| 28 | #include <time.h> |
| 29 | |
| 30 | #ifdef WIN32 |
| 31 | #include "talk/base/win32.h" |
| 32 | #endif |
| 33 | |
| 34 | #include "talk/base/common.h" |
| 35 | #include "talk/base/diskcache.h" |
| 36 | #include "talk/base/fileutils.h" |
| 37 | #include "talk/base/pathutils.h" |
| 38 | #include "talk/base/stream.h" |
| 39 | #include "talk/base/stringencode.h" |
| 40 | #include "talk/base/stringutils.h" |
| 41 | |
| 42 | #ifdef _DEBUG |
| 43 | #define TRANSPARENT_CACHE_NAMES 1 |
| 44 | #else // !_DEBUG |
| 45 | #define TRANSPARENT_CACHE_NAMES 0 |
| 46 | #endif // !_DEBUG |
| 47 | |
| 48 | namespace talk_base { |
| 49 | |
| 50 | class DiskCache; |
| 51 | |
| 52 | /////////////////////////////////////////////////////////////////////////////// |
| 53 | // DiskCacheAdapter |
| 54 | /////////////////////////////////////////////////////////////////////////////// |
| 55 | |
| 56 | class DiskCacheAdapter : public StreamAdapterInterface { |
| 57 | public: |
| 58 | DiskCacheAdapter(const DiskCache* cache, const std::string& id, size_t index, |
| 59 | StreamInterface* stream) |
| 60 | : StreamAdapterInterface(stream), cache_(cache), id_(id), index_(index) |
| 61 | { } |
| 62 | virtual ~DiskCacheAdapter() { |
| 63 | Close(); |
| 64 | cache_->ReleaseResource(id_, index_); |
| 65 | } |
| 66 | |
| 67 | private: |
| 68 | const DiskCache* cache_; |
| 69 | std::string id_; |
| 70 | size_t index_; |
| 71 | }; |
| 72 | |
| 73 | /////////////////////////////////////////////////////////////////////////////// |
| 74 | // DiskCache |
| 75 | /////////////////////////////////////////////////////////////////////////////// |
| 76 | |
| 77 | DiskCache::DiskCache() : max_cache_(0), total_size_(0), total_accessors_(0) { |
| 78 | } |
| 79 | |
| 80 | DiskCache::~DiskCache() { |
| 81 | ASSERT(0 == total_accessors_); |
| 82 | } |
| 83 | |
| 84 | bool DiskCache::Initialize(const std::string& folder, size_t size) { |
| 85 | if (!folder_.empty() || !Filesystem::CreateFolder(folder)) |
| 86 | return false; |
| 87 | |
| 88 | folder_ = folder; |
| 89 | max_cache_ = size; |
| 90 | ASSERT(0 == total_size_); |
| 91 | |
| 92 | if (!InitializeEntries()) |
| 93 | return false; |
| 94 | |
| 95 | return CheckLimit(); |
| 96 | } |
| 97 | |
| 98 | bool DiskCache::Purge() { |
| 99 | if (folder_.empty()) |
| 100 | return false; |
| 101 | |
| 102 | if (total_accessors_ > 0) { |
| 103 | LOG_F(LS_WARNING) << "Cache files open"; |
| 104 | return false; |
| 105 | } |
| 106 | |
| 107 | if (!PurgeFiles()) |
| 108 | return false; |
| 109 | |
| 110 | map_.clear(); |
| 111 | return true; |
| 112 | } |
| 113 | |
| 114 | bool DiskCache::LockResource(const std::string& id) { |
| 115 | Entry* entry = GetOrCreateEntry(id, true); |
| 116 | if (LS_LOCKED == entry->lock_state) |
| 117 | return false; |
| 118 | if ((LS_UNLOCKED == entry->lock_state) && (entry->accessors > 0)) |
| 119 | return false; |
| 120 | if ((total_size_ > max_cache_) && !CheckLimit()) { |
| 121 | LOG_F(LS_WARNING) << "Cache overfull"; |
| 122 | return false; |
| 123 | } |
| 124 | entry->lock_state = LS_LOCKED; |
| 125 | return true; |
| 126 | } |
| 127 | |
| 128 | StreamInterface* DiskCache::WriteResource(const std::string& id, size_t index) { |
| 129 | Entry* entry = GetOrCreateEntry(id, false); |
| 130 | if (LS_LOCKED != entry->lock_state) |
| 131 | return NULL; |
| 132 | |
| 133 | size_t previous_size = 0; |
| 134 | std::string filename(IdToFilename(id, index)); |
| 135 | FileStream::GetSize(filename, &previous_size); |
| 136 | ASSERT(previous_size <= entry->size); |
| 137 | if (previous_size > entry->size) { |
| 138 | previous_size = entry->size; |
| 139 | } |
| 140 | |
| 141 | scoped_ptr<FileStream> file(new FileStream); |
| 142 | if (!file->Open(filename, "wb", NULL)) { |
| 143 | LOG_F(LS_ERROR) << "Couldn't create cache file"; |
| 144 | return NULL; |
| 145 | } |
| 146 | |
| 147 | entry->streams = stdmax(entry->streams, index + 1); |
| 148 | entry->size -= previous_size; |
| 149 | total_size_ -= previous_size; |
| 150 | |
| 151 | entry->accessors += 1; |
| 152 | total_accessors_ += 1; |
| 153 | return new DiskCacheAdapter(this, id, index, file.release()); |
| 154 | } |
| 155 | |
| 156 | bool DiskCache::UnlockResource(const std::string& id) { |
| 157 | Entry* entry = GetOrCreateEntry(id, false); |
| 158 | if (LS_LOCKED != entry->lock_state) |
| 159 | return false; |
| 160 | |
| 161 | if (entry->accessors > 0) { |
| 162 | entry->lock_state = LS_UNLOCKING; |
| 163 | } else { |
| 164 | entry->lock_state = LS_UNLOCKED; |
| 165 | entry->last_modified = time(0); |
| 166 | CheckLimit(); |
| 167 | } |
| 168 | return true; |
| 169 | } |
| 170 | |
| 171 | StreamInterface* DiskCache::ReadResource(const std::string& id, |
| 172 | size_t index) const { |
| 173 | const Entry* entry = GetEntry(id); |
| 174 | if (LS_UNLOCKED != entry->lock_state) |
| 175 | return NULL; |
| 176 | if (index >= entry->streams) |
| 177 | return NULL; |
| 178 | |
| 179 | scoped_ptr<FileStream> file(new FileStream); |
| 180 | if (!file->Open(IdToFilename(id, index), "rb", NULL)) |
| 181 | return NULL; |
| 182 | |
| 183 | entry->accessors += 1; |
| 184 | total_accessors_ += 1; |
| 185 | return new DiskCacheAdapter(this, id, index, file.release()); |
| 186 | } |
| 187 | |
| 188 | bool DiskCache::HasResource(const std::string& id) const { |
| 189 | const Entry* entry = GetEntry(id); |
| 190 | return (NULL != entry) && (entry->streams > 0); |
| 191 | } |
| 192 | |
| 193 | bool DiskCache::HasResourceStream(const std::string& id, size_t index) const { |
| 194 | const Entry* entry = GetEntry(id); |
| 195 | if ((NULL == entry) || (index >= entry->streams)) |
| 196 | return false; |
| 197 | |
| 198 | std::string filename = IdToFilename(id, index); |
| 199 | |
| 200 | return FileExists(filename); |
| 201 | } |
| 202 | |
| 203 | bool DiskCache::DeleteResource(const std::string& id) { |
| 204 | Entry* entry = GetOrCreateEntry(id, false); |
| 205 | if (!entry) |
| 206 | return true; |
| 207 | |
| 208 | if ((LS_UNLOCKED != entry->lock_state) || (entry->accessors > 0)) |
| 209 | return false; |
| 210 | |
| 211 | bool success = true; |
| 212 | for (size_t index = 0; index < entry->streams; ++index) { |
| 213 | std::string filename = IdToFilename(id, index); |
| 214 | |
| 215 | if (!FileExists(filename)) |
| 216 | continue; |
| 217 | |
| 218 | if (!DeleteFile(filename)) { |
| 219 | LOG_F(LS_ERROR) << "Couldn't remove cache file: " << filename; |
| 220 | success = false; |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | total_size_ -= entry->size; |
| 225 | map_.erase(id); |
| 226 | return success; |
| 227 | } |
| 228 | |
| 229 | bool DiskCache::CheckLimit() { |
| 230 | #ifdef _DEBUG |
| 231 | // Temporary check to make sure everything is working correctly. |
| 232 | size_t cache_size = 0; |
| 233 | for (EntryMap::iterator it = map_.begin(); it != map_.end(); ++it) { |
| 234 | cache_size += it->second.size; |
| 235 | } |
| 236 | ASSERT(cache_size == total_size_); |
| 237 | #endif // _DEBUG |
| 238 | |
| 239 | // TODO: Replace this with a non-brain-dead algorithm for clearing out the |
| 240 | // oldest resources... something that isn't O(n^2) |
| 241 | while (total_size_ > max_cache_) { |
| 242 | EntryMap::iterator oldest = map_.end(); |
| 243 | for (EntryMap::iterator it = map_.begin(); it != map_.end(); ++it) { |
| 244 | if ((LS_UNLOCKED != it->second.lock_state) || (it->second.accessors > 0)) |
| 245 | continue; |
| 246 | oldest = it; |
| 247 | break; |
| 248 | } |
| 249 | if (oldest == map_.end()) { |
| 250 | LOG_F(LS_WARNING) << "All resources are locked!"; |
| 251 | return false; |
| 252 | } |
| 253 | for (EntryMap::iterator it = oldest++; it != map_.end(); ++it) { |
| 254 | if (it->second.last_modified < oldest->second.last_modified) { |
| 255 | oldest = it; |
| 256 | } |
| 257 | } |
| 258 | if (!DeleteResource(oldest->first)) { |
| 259 | LOG_F(LS_ERROR) << "Couldn't delete from cache!"; |
| 260 | return false; |
| 261 | } |
| 262 | } |
| 263 | return true; |
| 264 | } |
| 265 | |
| 266 | std::string DiskCache::IdToFilename(const std::string& id, size_t index) const { |
| 267 | #ifdef TRANSPARENT_CACHE_NAMES |
| 268 | // This escapes colons and other filesystem characters, so the user can't open |
| 269 | // special devices (like "COM1:"), or access other directories. |
| 270 | size_t buffer_size = id.length()*3 + 1; |
| 271 | char* buffer = new char[buffer_size]; |
| 272 | encode(buffer, buffer_size, id.data(), id.length(), |
| 273 | unsafe_filename_characters(), '%'); |
| 274 | // TODO: ASSERT(strlen(buffer) < FileSystem::MaxBasenameLength()); |
| 275 | #else // !TRANSPARENT_CACHE_NAMES |
| 276 | // We might want to just use a hash of the filename at some point, both for |
| 277 | // obfuscation, and to avoid both filename length and escaping issues. |
| 278 | ASSERT(false); |
| 279 | #endif // !TRANSPARENT_CACHE_NAMES |
| 280 | |
| 281 | char extension[32]; |
| 282 | sprintfn(extension, ARRAY_SIZE(extension), ".%u", index); |
| 283 | |
| 284 | Pathname pathname; |
| 285 | pathname.SetFolder(folder_); |
| 286 | pathname.SetBasename(buffer); |
| 287 | pathname.SetExtension(extension); |
| 288 | |
| 289 | #ifdef TRANSPARENT_CACHE_NAMES |
| 290 | delete [] buffer; |
| 291 | #endif // TRANSPARENT_CACHE_NAMES |
| 292 | |
| 293 | return pathname.pathname(); |
| 294 | } |
| 295 | |
| 296 | bool DiskCache::FilenameToId(const std::string& filename, std::string* id, |
| 297 | size_t* index) const { |
| 298 | Pathname pathname(filename); |
| 299 | unsigned tempdex; |
| 300 | if (1 != sscanf(pathname.extension().c_str(), ".%u", &tempdex)) |
| 301 | return false; |
| 302 | |
| 303 | *index = static_cast<size_t>(tempdex); |
| 304 | |
| 305 | size_t buffer_size = pathname.basename().length() + 1; |
| 306 | char* buffer = new char[buffer_size]; |
| 307 | decode(buffer, buffer_size, pathname.basename().data(), |
| 308 | pathname.basename().length(), '%'); |
| 309 | id->assign(buffer); |
| 310 | delete [] buffer; |
| 311 | return true; |
| 312 | } |
| 313 | |
| 314 | DiskCache::Entry* DiskCache::GetOrCreateEntry(const std::string& id, |
| 315 | bool create) { |
| 316 | EntryMap::iterator it = map_.find(id); |
| 317 | if (it != map_.end()) |
| 318 | return &it->second; |
| 319 | if (!create) |
| 320 | return NULL; |
| 321 | Entry e; |
| 322 | e.lock_state = LS_UNLOCKED; |
| 323 | e.accessors = 0; |
| 324 | e.size = 0; |
| 325 | e.streams = 0; |
| 326 | e.last_modified = time(0); |
| 327 | it = map_.insert(EntryMap::value_type(id, e)).first; |
| 328 | return &it->second; |
| 329 | } |
| 330 | |
| 331 | void DiskCache::ReleaseResource(const std::string& id, size_t index) const { |
| 332 | const Entry* entry = GetEntry(id); |
| 333 | if (!entry) { |
| 334 | LOG_F(LS_WARNING) << "Missing cache entry"; |
| 335 | ASSERT(false); |
| 336 | return; |
| 337 | } |
| 338 | |
| 339 | entry->accessors -= 1; |
| 340 | total_accessors_ -= 1; |
| 341 | |
| 342 | if (LS_UNLOCKED != entry->lock_state) { |
| 343 | // This is safe, because locked resources only issue WriteResource, which |
| 344 | // is non-const. Think about a better way to handle it. |
| 345 | DiskCache* this2 = const_cast<DiskCache*>(this); |
| 346 | Entry* entry2 = this2->GetOrCreateEntry(id, false); |
| 347 | |
| 348 | size_t new_size = 0; |
| 349 | std::string filename(IdToFilename(id, index)); |
| 350 | FileStream::GetSize(filename, &new_size); |
| 351 | entry2->size += new_size; |
| 352 | this2->total_size_ += new_size; |
| 353 | |
| 354 | if ((LS_UNLOCKING == entry->lock_state) && (0 == entry->accessors)) { |
| 355 | entry2->last_modified = time(0); |
| 356 | entry2->lock_state = LS_UNLOCKED; |
| 357 | this2->CheckLimit(); |
| 358 | } |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | /////////////////////////////////////////////////////////////////////////////// |
| 363 | |
| 364 | } // namespace talk_base |