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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 "base/path_service.h" | |
| 6 | |
| 7 #if defined(OS_WIN) | |
| 8 #include <windows.h> | |
| 9 #include <shellapi.h> | |
| 10 #include <shlobj.h> | |
| 11 #endif | |
| 12 | |
| 13 #include "base/containers/hash_tables.h" | |
| 14 #include "base/files/file_path.h" | |
| 15 #include "base/files/file_util.h" | |
| 16 #include "base/lazy_instance.h" | |
| 17 #include "base/logging.h" | |
| 18 #include "base/synchronization/lock.h" | |
| 19 | |
| 20 using base::FilePath; | |
| 21 using base::MakeAbsoluteFilePath; | |
| 22 | |
| 23 namespace base { | |
| 24 bool PathProvider(int key, FilePath* result); | |
| 25 #if defined(OS_WIN) | |
| 26 bool PathProviderWin(int key, FilePath* result); | |
| 27 #elif defined(OS_MACOSX) | |
| 28 bool PathProviderMac(int key, FilePath* result); | |
| 29 #elif defined(OS_ANDROID) | |
| 30 bool PathProviderAndroid(int key, FilePath* result); | |
| 31 #elif defined(OS_POSIX) | |
| 32 // PathProviderPosix is the default path provider on POSIX OSes other than | |
| 33 // Mac and Android. | |
| 34 bool PathProviderPosix(int key, FilePath* result); | |
| 35 #endif | |
| 36 } // namespace base | |
| 37 | |
| 38 namespace { | |
| 39 | |
| 40 typedef base::hash_map<int, FilePath> PathMap; | |
| 41 | |
| 42 // We keep a linked list of providers. In a debug build we ensure that no two | |
| 43 // providers claim overlapping keys. | |
| 44 struct Provider { | |
| 45 PathService::ProviderFunc func; | |
| 46 struct Provider* next; | |
| 47 #ifndef NDEBUG | |
| 48 int key_start; | |
| 49 int key_end; | |
| 50 #endif | |
| 51 bool is_static; | |
| 52 }; | |
| 53 | |
| 54 Provider base_provider = { | |
| 55 base::PathProvider, | |
| 56 NULL, | |
| 57 #ifndef NDEBUG | |
| 58 base::PATH_START, | |
| 59 base::PATH_END, | |
| 60 #endif | |
| 61 true | |
| 62 }; | |
| 63 | |
| 64 #if defined(OS_WIN) | |
| 65 Provider base_provider_win = { | |
| 66 base::PathProviderWin, | |
| 67 &base_provider, | |
| 68 #ifndef NDEBUG | |
| 69 base::PATH_WIN_START, | |
| 70 base::PATH_WIN_END, | |
| 71 #endif | |
| 72 true | |
| 73 }; | |
| 74 #endif | |
| 75 | |
| 76 #if defined(OS_MACOSX) | |
| 77 Provider base_provider_mac = { | |
| 78 base::PathProviderMac, | |
| 79 &base_provider, | |
| 80 #ifndef NDEBUG | |
| 81 base::PATH_MAC_START, | |
| 82 base::PATH_MAC_END, | |
| 83 #endif | |
| 84 true | |
| 85 }; | |
| 86 #endif | |
| 87 | |
| 88 #if defined(OS_ANDROID) | |
| 89 Provider base_provider_android = { | |
| 90 base::PathProviderAndroid, | |
| 91 &base_provider, | |
| 92 #ifndef NDEBUG | |
| 93 base::PATH_ANDROID_START, | |
| 94 base::PATH_ANDROID_END, | |
| 95 #endif | |
| 96 true | |
| 97 }; | |
| 98 #endif | |
| 99 | |
| 100 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID) | |
| 101 Provider base_provider_posix = { | |
| 102 base::PathProviderPosix, | |
| 103 &base_provider, | |
| 104 #ifndef NDEBUG | |
| 105 base::PATH_POSIX_START, | |
| 106 base::PATH_POSIX_END, | |
| 107 #endif | |
| 108 true | |
| 109 }; | |
| 110 #endif | |
| 111 | |
| 112 | |
| 113 struct PathData { | |
| 114 base::Lock lock; | |
| 115 PathMap cache; // Cache mappings from path key to path value. | |
| 116 PathMap overrides; // Track path overrides. | |
| 117 Provider* providers; // Linked list of path service providers. | |
| 118 bool cache_disabled; // Don't use cache if true; | |
| 119 | |
| 120 PathData() : cache_disabled(false) { | |
| 121 #if defined(OS_WIN) | |
| 122 providers = &base_provider_win; | |
| 123 #elif defined(OS_MACOSX) | |
| 124 providers = &base_provider_mac; | |
| 125 #elif defined(OS_ANDROID) | |
| 126 providers = &base_provider_android; | |
| 127 #elif defined(OS_POSIX) | |
| 128 providers = &base_provider_posix; | |
| 129 #endif | |
| 130 } | |
| 131 | |
| 132 ~PathData() { | |
| 133 Provider* p = providers; | |
| 134 while (p) { | |
| 135 Provider* next = p->next; | |
| 136 if (!p->is_static) | |
| 137 delete p; | |
| 138 p = next; | |
| 139 } | |
| 140 } | |
| 141 }; | |
| 142 | |
| 143 static base::LazyInstance<PathData> g_path_data = LAZY_INSTANCE_INITIALIZER; | |
| 144 | |
| 145 static PathData* GetPathData() { | |
| 146 return g_path_data.Pointer(); | |
| 147 } | |
| 148 | |
| 149 // Tries to find |key| in the cache. |path_data| should be locked by the caller! | |
| 150 bool LockedGetFromCache(int key, const PathData* path_data, FilePath* result) { | |
| 151 if (path_data->cache_disabled) | |
| 152 return false; | |
| 153 // check for a cached version | |
| 154 PathMap::const_iterator it = path_data->cache.find(key); | |
| 155 if (it != path_data->cache.end()) { | |
| 156 *result = it->second; | |
| 157 return true; | |
| 158 } | |
| 159 return false; | |
| 160 } | |
| 161 | |
| 162 // Tries to find |key| in the overrides map. |path_data| should be locked by the | |
| 163 // caller! | |
| 164 bool LockedGetFromOverrides(int key, PathData* path_data, FilePath* result) { | |
| 165 // check for an overridden version. | |
| 166 PathMap::const_iterator it = path_data->overrides.find(key); | |
| 167 if (it != path_data->overrides.end()) { | |
| 168 if (!path_data->cache_disabled) | |
| 169 path_data->cache[key] = it->second; | |
| 170 *result = it->second; | |
| 171 return true; | |
| 172 } | |
| 173 return false; | |
| 174 } | |
| 175 | |
| 176 } // namespace | |
| 177 | |
| 178 // TODO(brettw): this function does not handle long paths (filename > MAX_PATH) | |
| 179 // characters). This isn't supported very well by Windows right now, so it is | |
| 180 // moot, but we should keep this in mind for the future. | |
| 181 // static | |
| 182 bool PathService::Get(int key, FilePath* result) { | |
| 183 PathData* path_data = GetPathData(); | |
| 184 DCHECK(path_data); | |
| 185 DCHECK(result); | |
| 186 DCHECK_GE(key, base::DIR_CURRENT); | |
| 187 | |
| 188 // special case the current directory because it can never be cached | |
| 189 if (key == base::DIR_CURRENT) | |
| 190 return base::GetCurrentDirectory(result); | |
| 191 | |
| 192 Provider* provider = NULL; | |
| 193 { | |
| 194 base::AutoLock scoped_lock(path_data->lock); | |
| 195 if (LockedGetFromCache(key, path_data, result)) | |
| 196 return true; | |
| 197 | |
| 198 if (LockedGetFromOverrides(key, path_data, result)) | |
| 199 return true; | |
| 200 | |
| 201 // Get the beginning of the list while it is still locked. | |
| 202 provider = path_data->providers; | |
| 203 } | |
| 204 | |
| 205 FilePath path; | |
| 206 | |
| 207 // Iterating does not need the lock because only the list head might be | |
| 208 // modified on another thread. | |
| 209 while (provider) { | |
| 210 if (provider->func(key, &path)) | |
| 211 break; | |
| 212 DCHECK(path.empty()) << "provider should not have modified path"; | |
| 213 provider = provider->next; | |
| 214 } | |
| 215 | |
| 216 if (path.empty()) | |
| 217 return false; | |
| 218 | |
| 219 if (path.ReferencesParent()) { | |
| 220 // Make sure path service never returns a path with ".." in it. | |
| 221 path = MakeAbsoluteFilePath(path); | |
| 222 if (path.empty()) | |
| 223 return false; | |
| 224 } | |
| 225 *result = path; | |
| 226 | |
| 227 base::AutoLock scoped_lock(path_data->lock); | |
| 228 if (!path_data->cache_disabled) | |
| 229 path_data->cache[key] = path; | |
| 230 | |
| 231 return true; | |
| 232 } | |
| 233 | |
| 234 // static | |
| 235 bool PathService::Override(int key, const FilePath& path) { | |
| 236 // Just call the full function with true for the value of |create|, and | |
| 237 // assume that |path| may not be absolute yet. | |
| 238 return OverrideAndCreateIfNeeded(key, path, false, true); | |
| 239 } | |
| 240 | |
| 241 // static | |
| 242 bool PathService::OverrideAndCreateIfNeeded(int key, | |
| 243 const FilePath& path, | |
| 244 bool is_absolute, | |
| 245 bool create) { | |
| 246 PathData* path_data = GetPathData(); | |
| 247 DCHECK(path_data); | |
| 248 DCHECK_GT(key, base::DIR_CURRENT) << "invalid path key"; | |
| 249 | |
| 250 FilePath file_path = path; | |
| 251 | |
| 252 // For some locations this will fail if called from inside the sandbox there- | |
| 253 // fore we protect this call with a flag. | |
| 254 if (create) { | |
| 255 // Make sure the directory exists. We need to do this before we translate | |
| 256 // this to the absolute path because on POSIX, MakeAbsoluteFilePath fails | |
| 257 // if called on a non-existent path. | |
| 258 if (!base::PathExists(file_path) && | |
| 259 !base::CreateDirectory(file_path)) | |
| 260 return false; | |
| 261 } | |
| 262 | |
| 263 // We need to have an absolute path. | |
| 264 if (!is_absolute) { | |
| 265 file_path = MakeAbsoluteFilePath(file_path); | |
| 266 if (file_path.empty()) | |
| 267 return false; | |
| 268 } | |
| 269 DCHECK(file_path.IsAbsolute()); | |
| 270 | |
| 271 base::AutoLock scoped_lock(path_data->lock); | |
| 272 | |
| 273 // Clear the cache now. Some of its entries could have depended | |
| 274 // on the value we are overriding, and are now out of sync with reality. | |
| 275 path_data->cache.clear(); | |
| 276 | |
| 277 path_data->overrides[key] = file_path; | |
| 278 | |
| 279 return true; | |
| 280 } | |
| 281 | |
| 282 // static | |
| 283 bool PathService::RemoveOverride(int key) { | |
| 284 PathData* path_data = GetPathData(); | |
| 285 DCHECK(path_data); | |
| 286 | |
| 287 base::AutoLock scoped_lock(path_data->lock); | |
| 288 | |
| 289 if (path_data->overrides.find(key) == path_data->overrides.end()) | |
| 290 return false; | |
| 291 | |
| 292 // Clear the cache now. Some of its entries could have depended on the value | |
| 293 // we are going to remove, and are now out of sync. | |
| 294 path_data->cache.clear(); | |
| 295 | |
| 296 path_data->overrides.erase(key); | |
| 297 | |
| 298 return true; | |
| 299 } | |
| 300 | |
| 301 // static | |
| 302 void PathService::RegisterProvider(ProviderFunc func, int key_start, | |
| 303 int key_end) { | |
| 304 PathData* path_data = GetPathData(); | |
| 305 DCHECK(path_data); | |
| 306 DCHECK_GT(key_end, key_start); | |
| 307 | |
| 308 Provider* p; | |
| 309 | |
| 310 p = new Provider; | |
| 311 p->is_static = false; | |
| 312 p->func = func; | |
| 313 #ifndef NDEBUG | |
| 314 p->key_start = key_start; | |
| 315 p->key_end = key_end; | |
| 316 #endif | |
| 317 | |
| 318 base::AutoLock scoped_lock(path_data->lock); | |
| 319 | |
| 320 #ifndef NDEBUG | |
| 321 Provider *iter = path_data->providers; | |
| 322 while (iter) { | |
| 323 DCHECK(key_start >= iter->key_end || key_end <= iter->key_start) << | |
| 324 "path provider collision"; | |
| 325 iter = iter->next; | |
| 326 } | |
| 327 #endif | |
| 328 | |
| 329 p->next = path_data->providers; | |
| 330 path_data->providers = p; | |
| 331 } | |
| 332 | |
| 333 // static | |
| 334 void PathService::DisableCache() { | |
| 335 PathData* path_data = GetPathData(); | |
| 336 DCHECK(path_data); | |
| 337 | |
| 338 base::AutoLock scoped_lock(path_data->lock); | |
| 339 path_data->cache.clear(); | |
| 340 path_data->cache_disabled = true; | |
| 341 } | |
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