Luis Hector Chavez | 645501c | 2016-12-28 10:56:26 -0800 | [diff] [blame] | 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" |
Luis Hector Chavez | 645501c | 2016-12-28 10:56:26 -0800 | [diff] [blame] | 16 | #include "base/logging.h" |
| 17 | #include "base/synchronization/lock.h" |
| 18 | #include "build/build_config.h" |
| 19 | |
| 20 | namespace base { |
| 21 | |
| 22 | bool PathProvider(int key, FilePath* result); |
| 23 | |
| 24 | #if defined(OS_WIN) |
| 25 | bool PathProviderWin(int key, FilePath* result); |
| 26 | #elif defined(OS_MACOSX) |
| 27 | bool PathProviderMac(int key, FilePath* result); |
| 28 | #elif defined(OS_ANDROID) |
| 29 | bool PathProviderAndroid(int key, FilePath* result); |
| 30 | #elif defined(OS_POSIX) |
| 31 | // PathProviderPosix is the default path provider on POSIX OSes other than |
| 32 | // Mac and Android. |
| 33 | bool PathProviderPosix(int key, FilePath* result); |
| 34 | #endif |
| 35 | |
| 36 | namespace { |
| 37 | |
| 38 | typedef hash_map<int, FilePath> PathMap; |
| 39 | |
| 40 | // We keep a linked list of providers. In a debug build we ensure that no two |
| 41 | // providers claim overlapping keys. |
| 42 | struct Provider { |
| 43 | PathService::ProviderFunc func; |
| 44 | struct Provider* next; |
| 45 | #ifndef NDEBUG |
| 46 | int key_start; |
| 47 | int key_end; |
| 48 | #endif |
| 49 | bool is_static; |
| 50 | }; |
| 51 | |
| 52 | Provider base_provider = { |
| 53 | PathProvider, |
| 54 | NULL, |
| 55 | #ifndef NDEBUG |
| 56 | PATH_START, |
| 57 | PATH_END, |
| 58 | #endif |
| 59 | true |
| 60 | }; |
| 61 | |
| 62 | #if defined(OS_WIN) |
| 63 | Provider base_provider_win = { |
| 64 | PathProviderWin, |
| 65 | &base_provider, |
| 66 | #ifndef NDEBUG |
| 67 | PATH_WIN_START, |
| 68 | PATH_WIN_END, |
| 69 | #endif |
| 70 | true |
| 71 | }; |
| 72 | #endif |
| 73 | |
| 74 | #if defined(OS_MACOSX) |
| 75 | Provider base_provider_mac = { |
| 76 | PathProviderMac, |
| 77 | &base_provider, |
| 78 | #ifndef NDEBUG |
| 79 | PATH_MAC_START, |
| 80 | PATH_MAC_END, |
| 81 | #endif |
| 82 | true |
| 83 | }; |
| 84 | #endif |
| 85 | |
| 86 | #if defined(OS_ANDROID) |
| 87 | Provider base_provider_android = { |
| 88 | PathProviderAndroid, |
| 89 | &base_provider, |
| 90 | #ifndef NDEBUG |
| 91 | PATH_ANDROID_START, |
| 92 | PATH_ANDROID_END, |
| 93 | #endif |
| 94 | true |
| 95 | }; |
| 96 | #endif |
| 97 | |
| 98 | #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID) |
| 99 | Provider base_provider_posix = { |
| 100 | PathProviderPosix, |
| 101 | &base_provider, |
| 102 | #ifndef NDEBUG |
| 103 | PATH_POSIX_START, |
| 104 | PATH_POSIX_END, |
| 105 | #endif |
| 106 | true |
| 107 | }; |
| 108 | #endif |
| 109 | |
| 110 | |
| 111 | struct PathData { |
| 112 | Lock lock; |
| 113 | PathMap cache; // Cache mappings from path key to path value. |
| 114 | PathMap overrides; // Track path overrides. |
| 115 | Provider* providers; // Linked list of path service providers. |
| 116 | bool cache_disabled; // Don't use cache if true; |
| 117 | |
| 118 | PathData() : cache_disabled(false) { |
| 119 | #if defined(OS_WIN) |
| 120 | providers = &base_provider_win; |
| 121 | #elif defined(OS_MACOSX) |
| 122 | providers = &base_provider_mac; |
| 123 | #elif defined(OS_ANDROID) |
| 124 | providers = &base_provider_android; |
| 125 | #elif defined(OS_POSIX) |
| 126 | providers = &base_provider_posix; |
| 127 | #endif |
| 128 | } |
| 129 | }; |
| 130 | |
Luis Hector Chavez | 645501c | 2016-12-28 10:56:26 -0800 | [diff] [blame] | 131 | static PathData* GetPathData() { |
Jay Civelli | cfc1eaa | 2017-08-21 17:18:10 -0700 | [diff] [blame] | 132 | static auto* path_data = new PathData(); |
| 133 | return path_data; |
Luis Hector Chavez | 645501c | 2016-12-28 10:56:26 -0800 | [diff] [blame] | 134 | } |
| 135 | |
| 136 | // Tries to find |key| in the cache. |path_data| should be locked by the caller! |
| 137 | bool LockedGetFromCache(int key, const PathData* path_data, FilePath* result) { |
| 138 | if (path_data->cache_disabled) |
| 139 | return false; |
| 140 | // check for a cached version |
| 141 | PathMap::const_iterator it = path_data->cache.find(key); |
| 142 | if (it != path_data->cache.end()) { |
| 143 | *result = it->second; |
| 144 | return true; |
| 145 | } |
| 146 | return false; |
| 147 | } |
| 148 | |
| 149 | // Tries to find |key| in the overrides map. |path_data| should be locked by the |
| 150 | // caller! |
| 151 | bool LockedGetFromOverrides(int key, PathData* path_data, FilePath* result) { |
| 152 | // check for an overridden version. |
| 153 | PathMap::const_iterator it = path_data->overrides.find(key); |
| 154 | if (it != path_data->overrides.end()) { |
| 155 | if (!path_data->cache_disabled) |
| 156 | path_data->cache[key] = it->second; |
| 157 | *result = it->second; |
| 158 | return true; |
| 159 | } |
| 160 | return false; |
| 161 | } |
| 162 | |
| 163 | } // namespace |
| 164 | |
| 165 | // TODO(brettw): this function does not handle long paths (filename > MAX_PATH) |
| 166 | // characters). This isn't supported very well by Windows right now, so it is |
| 167 | // moot, but we should keep this in mind for the future. |
| 168 | // static |
| 169 | bool PathService::Get(int key, FilePath* result) { |
| 170 | PathData* path_data = GetPathData(); |
| 171 | DCHECK(path_data); |
| 172 | DCHECK(result); |
| 173 | DCHECK_GE(key, DIR_CURRENT); |
| 174 | |
| 175 | // special case the current directory because it can never be cached |
| 176 | if (key == DIR_CURRENT) |
| 177 | return GetCurrentDirectory(result); |
| 178 | |
| 179 | Provider* provider = NULL; |
| 180 | { |
| 181 | AutoLock scoped_lock(path_data->lock); |
| 182 | if (LockedGetFromCache(key, path_data, result)) |
| 183 | return true; |
| 184 | |
| 185 | if (LockedGetFromOverrides(key, path_data, result)) |
| 186 | return true; |
| 187 | |
| 188 | // Get the beginning of the list while it is still locked. |
| 189 | provider = path_data->providers; |
| 190 | } |
| 191 | |
| 192 | FilePath path; |
| 193 | |
| 194 | // Iterating does not need the lock because only the list head might be |
| 195 | // modified on another thread. |
| 196 | while (provider) { |
| 197 | if (provider->func(key, &path)) |
| 198 | break; |
| 199 | DCHECK(path.empty()) << "provider should not have modified path"; |
| 200 | provider = provider->next; |
| 201 | } |
| 202 | |
| 203 | if (path.empty()) |
| 204 | return false; |
| 205 | |
| 206 | if (path.ReferencesParent()) { |
| 207 | // Make sure path service never returns a path with ".." in it. |
| 208 | path = MakeAbsoluteFilePath(path); |
| 209 | if (path.empty()) |
| 210 | return false; |
| 211 | } |
| 212 | *result = path; |
| 213 | |
| 214 | AutoLock scoped_lock(path_data->lock); |
| 215 | if (!path_data->cache_disabled) |
| 216 | path_data->cache[key] = path; |
| 217 | |
| 218 | return true; |
| 219 | } |
| 220 | |
| 221 | // static |
| 222 | bool PathService::Override(int key, const FilePath& path) { |
| 223 | // Just call the full function with true for the value of |create|, and |
| 224 | // assume that |path| may not be absolute yet. |
| 225 | return OverrideAndCreateIfNeeded(key, path, false, true); |
| 226 | } |
| 227 | |
| 228 | // static |
| 229 | bool PathService::OverrideAndCreateIfNeeded(int key, |
| 230 | const FilePath& path, |
| 231 | bool is_absolute, |
| 232 | bool create) { |
| 233 | PathData* path_data = GetPathData(); |
| 234 | DCHECK(path_data); |
| 235 | DCHECK_GT(key, DIR_CURRENT) << "invalid path key"; |
| 236 | |
| 237 | FilePath file_path = path; |
| 238 | |
| 239 | // For some locations this will fail if called from inside the sandbox there- |
| 240 | // fore we protect this call with a flag. |
| 241 | if (create) { |
| 242 | // Make sure the directory exists. We need to do this before we translate |
| 243 | // this to the absolute path because on POSIX, MakeAbsoluteFilePath fails |
| 244 | // if called on a non-existent path. |
| 245 | if (!PathExists(file_path) && !CreateDirectory(file_path)) |
| 246 | return false; |
| 247 | } |
| 248 | |
| 249 | // We need to have an absolute path. |
| 250 | if (!is_absolute) { |
| 251 | file_path = MakeAbsoluteFilePath(file_path); |
| 252 | if (file_path.empty()) |
| 253 | return false; |
| 254 | } |
| 255 | DCHECK(file_path.IsAbsolute()); |
| 256 | |
| 257 | AutoLock scoped_lock(path_data->lock); |
| 258 | |
| 259 | // Clear the cache now. Some of its entries could have depended |
| 260 | // on the value we are overriding, and are now out of sync with reality. |
| 261 | path_data->cache.clear(); |
| 262 | |
| 263 | path_data->overrides[key] = file_path; |
| 264 | |
| 265 | return true; |
| 266 | } |
| 267 | |
| 268 | // static |
| 269 | bool PathService::RemoveOverride(int key) { |
| 270 | PathData* path_data = GetPathData(); |
| 271 | DCHECK(path_data); |
| 272 | |
| 273 | AutoLock scoped_lock(path_data->lock); |
| 274 | |
| 275 | if (path_data->overrides.find(key) == path_data->overrides.end()) |
| 276 | return false; |
| 277 | |
| 278 | // Clear the cache now. Some of its entries could have depended on the value |
| 279 | // we are going to remove, and are now out of sync. |
| 280 | path_data->cache.clear(); |
| 281 | |
| 282 | path_data->overrides.erase(key); |
| 283 | |
| 284 | return true; |
| 285 | } |
| 286 | |
| 287 | // static |
| 288 | void PathService::RegisterProvider(ProviderFunc func, int key_start, |
| 289 | int key_end) { |
| 290 | PathData* path_data = GetPathData(); |
| 291 | DCHECK(path_data); |
| 292 | DCHECK_GT(key_end, key_start); |
| 293 | |
| 294 | Provider* p; |
| 295 | |
| 296 | p = new Provider; |
| 297 | p->is_static = false; |
| 298 | p->func = func; |
| 299 | #ifndef NDEBUG |
| 300 | p->key_start = key_start; |
| 301 | p->key_end = key_end; |
| 302 | #endif |
| 303 | |
| 304 | AutoLock scoped_lock(path_data->lock); |
| 305 | |
| 306 | #ifndef NDEBUG |
| 307 | Provider *iter = path_data->providers; |
| 308 | while (iter) { |
| 309 | DCHECK(key_start >= iter->key_end || key_end <= iter->key_start) << |
| 310 | "path provider collision"; |
| 311 | iter = iter->next; |
| 312 | } |
| 313 | #endif |
| 314 | |
| 315 | p->next = path_data->providers; |
| 316 | path_data->providers = p; |
| 317 | } |
| 318 | |
| 319 | // static |
| 320 | void PathService::DisableCache() { |
| 321 | PathData* path_data = GetPathData(); |
| 322 | DCHECK(path_data); |
| 323 | |
| 324 | AutoLock scoped_lock(path_data->lock); |
| 325 | path_data->cache.clear(); |
| 326 | path_data->cache_disabled = true; |
| 327 | } |
| 328 | |
| 329 | } // namespace base |