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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_PATH_SERVICE_H_
#define BASE_PATH_SERVICE_H_
#pragma once
#include <string>
#include "base/base_export.h"
#include "base/base_paths.h"
#include "build/build_config.h"
class FilePath;
// The path service is a global table mapping keys to file system paths. It is
// OK to use this service from multiple threads.
//
class BASE_EXPORT PathService {
public:
// Retrieves a path to a special directory or file and places it into the
// string pointed to by 'path'. If you ask for a directory it is guaranteed
// to NOT have a path separator at the end. For example, "c:\windows\temp"
// Directories are also guaranteed to exist when this function succeeds.
//
// Returns true if the directory or file was successfully retrieved. On
// failure, 'path' will not be changed.
static bool Get(int key, FilePath* path);
// Overrides the path to a special directory or file. This cannot be used to
// change the value of DIR_CURRENT, but that should be obvious. Also, if the
// path specifies a directory that does not exist, the directory will be
// created by this method. This method returns true if successful.
//
// If the given path is relative, then it will be resolved against
// DIR_CURRENT.
//
// WARNING: Consumers of PathService::Get may expect paths to be constant
// over the lifetime of the app, so this method should be used with caution.
static bool Override(int key, const FilePath& path);
// This function does the same as PathService::Override but it takes an extra
// parameter |create| which guides whether the directory to be overriden must
// be created in case it doesn't exist already.
static bool OverrideAndCreateIfNeeded(int key,
const FilePath& path,
bool create);
// To extend the set of supported keys, you can register a path provider,
// which is just a function mirroring PathService::Get. The ProviderFunc
// returns false if it cannot provide a non-empty path for the given key.
// Otherwise, true is returned.
//
// WARNING: This function could be called on any thread from which the
// PathService is used, so a the ProviderFunc MUST BE THREADSAFE.
//
typedef bool (*ProviderFunc)(int, FilePath*);
// Call to register a path provider. You must specify the range "[key_start,
// key_end)" of supported path keys.
static void RegisterProvider(ProviderFunc provider,
int key_start,
int key_end);
private:
static bool GetFromCache(int key, FilePath* path);
static bool GetFromOverrides(int key, FilePath* path);
static void AddToCache(int key, const FilePath& path);
};
#endif // BASE_PATH_SERVICE_H_
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