1 // Copyright (c) 2006-2008 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 "build/build_config.h" 9 10 #include <string> 11 12 #include "base/base_paths.h" 13 14 class FilePath; 15 16 // The path service is a global table mapping keys to file system paths. It is 17 // OK to use this service from multiple threads. 18 // 19 class PathService { 20 public: 21 // Retrieves a path to a special directory or file and places it into the 22 // string pointed to by 'path'. If you ask for a directory it is guaranteed 23 // to NOT have a path separator at the end. For example, "c:\windows\temp" 24 // Directories are also guaranteed to exist when this function succeeds. 25 // 26 // Returns true if the directory or file was successfully retrieved. On 27 // failure, 'path' will not be changed. 28 static bool Get(int key, FilePath* path); 29 #if defined(OS_WIN) 30 // This version, producing a wstring, is deprecated and only kept around 31 // until we can fix all callers. 32 static bool Get(int key, std::wstring* path); 33 #endif 34 35 // Overrides the path to a special directory or file. This cannot be used to 36 // change the value of DIR_CURRENT, but that should be obvious. Also, if the 37 // path specifies a directory that does not exist, the directory will be 38 // created by this method. This method returns true if successful. 39 // 40 // If the given path is relative, then it will be resolved against 41 // DIR_CURRENT. 42 // 43 // WARNING: Consumers of PathService::Get may expect paths to be constant 44 // over the lifetime of the app, so this method should be used with caution. 45 static bool Override(int key, const FilePath& path); 46 47 // Return whether a path was overridden. 48 static bool IsOverridden(int key); 49 50 // To extend the set of supported keys, you can register a path provider, 51 // which is just a function mirroring PathService::Get. The ProviderFunc 52 // returns false if it cannot provide a non-empty path for the given key. 53 // Otherwise, true is returned. 54 // 55 // WARNING: This function could be called on any thread from which the 56 // PathService is used, so a the ProviderFunc MUST BE THREADSAFE. 57 // 58 typedef bool (*ProviderFunc)(int, FilePath*); 59 60 // Call to register a path provider. You must specify the range "[key_start, 61 // key_end)" of supported path keys. 62 static void RegisterProvider(ProviderFunc provider, 63 int key_start, 64 int key_end); 65 private: 66 static bool GetFromCache(int key, FilePath* path); 67 static void AddToCache(int key, const FilePath& path); 68 }; 69 70 #endif // BASE_PATH_SERVICE_H_ 71
