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 #ifndef BASE_PATH_SERVICE_H_ 6 #define BASE_PATH_SERVICE_H_ 7 8 #include <string> 9 10 #include "base/base_export.h" 11 #include "base/base_paths.h" 12 #include "base/gtest_prod_util.h" 13 #include "build/build_config.h" 14 15 namespace base { 16 class FilePath; 17 class ScopedPathOverride; 18 } // namespace 19 20 // The path service is a global table mapping keys to file system paths. It is 21 // OK to use this service from multiple threads. 22 // 23 class BASE_EXPORT PathService { 24 public: 25 // Retrieves a path to a special directory or file and places it into the 26 // string pointed to by 'path'. If you ask for a directory it is guaranteed 27 // to NOT have a path separator at the end. For example, "c:\windows\temp" 28 // Directories are also guaranteed to exist when this function succeeds. 29 // 30 // Returns true if the directory or file was successfully retrieved. On 31 // failure, 'path' will not be changed. 32 static bool Get(int key, base::FilePath* path); 33 34 // Overrides the path to a special directory or file. This cannot be used to 35 // change the value of DIR_CURRENT, but that should be obvious. Also, if the 36 // path specifies a directory that does not exist, the directory will be 37 // created by this method. This method returns true if successful. 38 // 39 // If the given path is relative, then it will be resolved against 40 // DIR_CURRENT. 41 // 42 // WARNING: Consumers of PathService::Get may expect paths to be constant 43 // over the lifetime of the app, so this method should be used with caution. 44 static bool Override(int key, const base::FilePath& path); 45 46 // This function does the same as PathService::Override but it takes an extra 47 // parameter |create| which guides whether the directory to be overriden must 48 // be created in case it doesn't exist already. 49 static bool OverrideAndCreateIfNeeded(int key, 50 const base::FilePath& path, 51 bool create); 52 53 // To extend the set of supported keys, you can register a path provider, 54 // which is just a function mirroring PathService::Get. The ProviderFunc 55 // returns false if it cannot provide a non-empty path for the given key. 56 // Otherwise, true is returned. 57 // 58 // WARNING: This function could be called on any thread from which the 59 // PathService is used, so a the ProviderFunc MUST BE THREADSAFE. 60 // 61 typedef bool (*ProviderFunc)(int, base::FilePath*); 62 63 // Call to register a path provider. You must specify the range "[key_start, 64 // key_end)" of supported path keys. 65 static void RegisterProvider(ProviderFunc provider, 66 int key_start, 67 int key_end); 68 69 // Disable internal cache. 70 static void DisableCache(); 71 72 private: 73 friend class base::ScopedPathOverride; 74 FRIEND_TEST_ALL_PREFIXES(PathServiceTest, RemoveOverride); 75 76 // Removes an override for a special directory or file. Returns true if there 77 // was an override to remove or false if none was present. 78 // NOTE: This function is intended to be used by tests only! 79 static bool RemoveOverride(int key); 80 }; 81 82 #endif // BASE_PATH_SERVICE_H_ 83
