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 17 class FilePath; 18 class ScopedPathOverride; 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, 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 // 45 // Unit tests generally should use ScopedPathOverride instead. Overrides from 46 // one test should not carry over to another. 47 static bool Override(int key, const FilePath& path); 48 49 // This function does the same as PathService::Override but it takes extra 50 // parameters: 51 // - |is_absolute| indicates that |path| has already been expanded into an 52 // absolute path, otherwise MakeAbsoluteFilePath() will be used. This is 53 // useful to override paths that may not exist yet, since MakeAbsoluteFilePath 54 // fails for those. Note that MakeAbsoluteFilePath also expands symbolic 55 // links, even if path.IsAbsolute() is already true. 56 // - |create| guides whether the directory to be overriden must 57 // be created in case it doesn't exist already. 58 static bool OverrideAndCreateIfNeeded(int key, 59 const FilePath& path, 60 bool is_absolute, 61 bool create); 62 63 // To extend the set of supported keys, you can register a path provider, 64 // which is just a function mirroring PathService::Get. The ProviderFunc 65 // returns false if it cannot provide a non-empty path for the given key. 66 // Otherwise, true is returned. 67 // 68 // WARNING: This function could be called on any thread from which the 69 // PathService is used, so a the ProviderFunc MUST BE THREADSAFE. 70 // 71 typedef bool (*ProviderFunc)(int, FilePath*); 72 73 // Call to register a path provider. You must specify the range "[key_start, 74 // key_end)" of supported path keys. 75 static void RegisterProvider(ProviderFunc provider, 76 int key_start, 77 int key_end); 78 79 // Disable internal cache. 80 static void DisableCache(); 81 82 private: 83 friend class ScopedPathOverride; 84 FRIEND_TEST_ALL_PREFIXES(PathServiceTest, RemoveOverride); 85 86 // Removes an override for a special directory or file. Returns true if there 87 // was an override to remove or false if none was present. 88 // NOTE: This function is intended to be used by tests only! 89 static bool RemoveOverride(int key); 90 }; 91 92 } // namespace base 93 94 // TODO(brettw) Convert all callers to using the base namespace and remove this. 95 using base::PathService; 96 97 #endif // BASE_PATH_SERVICE_H_ 98
