1 // Copyright 2012 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef BASE_PATH_SERVICE_H_
6 #define BASE_PATH_SERVICE_H_
8 #include "base/base_export.h"
9 #include "base/base_paths.h"
10 #include "base/gtest_prod_util.h"
11 #include "build/build_config.h"
16 class ScopedPathOverride;
18 // The path service is a global table mapping keys to file system paths. It is
19 // OK to use this service from multiple threads.
21 class BASE_EXPORT PathService {
23 // Populates |path| with a special directory or file. Returns true on success,
24 // in which case |path| is guaranteed to have a non-empty value. On failure,
25 // |path| will not be changed.
26 static bool Get(int key, FilePath* path);
28 // Returns the corresponding path; CHECKs that the operation succeeds.
29 static FilePath CheckedGet(int key);
31 // Overrides the path to a special directory or file. This cannot be used to
32 // change the value of DIR_CURRENT, but that should be obvious. Also, if the
33 // path specifies a directory that does not exist, the directory will be
34 // created by this method. This method returns true if successful.
36 // If the given path is relative, then it will be resolved against
39 // WARNING: Consumers of PathService::Get may expect paths to be constant
40 // over the lifetime of the app, so this method should be used with caution.
42 // Unit tests generally should use ScopedPathOverride instead. Overrides from
43 // one test should not carry over to another.
44 static bool Override(int key, const FilePath& path);
46 // This function does the same as PathService::Override but it takes extra
48 // - |is_absolute| indicates that |path| has already been expanded into an
49 // absolute path, otherwise MakeAbsoluteFilePath() will be used. This is
50 // useful to override paths that may not exist yet, since MakeAbsoluteFilePath
51 // fails for those. Note that MakeAbsoluteFilePath also expands symbolic
52 // links, even if path.IsAbsolute() is already true.
53 // - |create| guides whether the directory to be overriden must
54 // be created in case it doesn't exist already.
55 static bool OverrideAndCreateIfNeeded(int key,
60 // Returns whether an override is present for a special directory or file.
61 static bool IsOverriddenForTesting(int key);
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.
68 // WARNING: This function could be called on any thread from which the
69 // PathService is used, so a the ProviderFunc MUST BE THREADSAFE.
71 typedef bool (*ProviderFunc)(int, FilePath*);
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,
79 // Disable internal cache.
80 static void DisableCache();
83 friend class ScopedPathOverride;
84 FRIEND_TEST_ALL_PREFIXES(PathServiceTest, RemoveOverride);
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 static bool RemoveOverrideForTests(int key);
93 #endif // BASE_PATH_SERVICE_H_