1// Copyright (c) 2011 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_ENVIRONMENT_H_ 6#define BASE_ENVIRONMENT_H_ 7 8#include <map> 9#include <string> 10 11#include "base/base_export.h" 12#include "base/memory/scoped_ptr.h" 13#include "base/strings/string16.h" 14#include "build/build_config.h" 15 16namespace base { 17 18namespace env_vars { 19 20#if defined(OS_POSIX) 21BASE_EXPORT extern const char kHome[]; 22#endif 23 24} // namespace env_vars 25 26class BASE_EXPORT Environment { 27 public: 28 virtual ~Environment(); 29 30 // Static factory method that returns the implementation that provide the 31 // appropriate platform-specific instance. 32 static Environment* Create(); 33 34 // Gets an environment variable's value and stores it in |result|. 35 // Returns false if the key is unset. 36 virtual bool GetVar(const char* variable_name, std::string* result) = 0; 37 38 // Syntactic sugar for GetVar(variable_name, NULL); 39 virtual bool HasVar(const char* variable_name); 40 41 // Returns true on success, otherwise returns false. 42 virtual bool SetVar(const char* variable_name, 43 const std::string& new_value) = 0; 44 45 // Returns true on success, otherwise returns false. 46 virtual bool UnSetVar(const char* variable_name) = 0; 47}; 48 49 50#if defined(OS_WIN) 51 52typedef string16 NativeEnvironmentString; 53typedef std::map<NativeEnvironmentString, NativeEnvironmentString> 54 EnvironmentMap; 55 56// Returns a modified environment vector constructed from the given environment 57// and the list of changes given in |changes|. Each key in the environment is 58// matched against the first element of the pairs. In the event of a match, the 59// value is replaced by the second of the pair, unless the second is empty, in 60// which case the key-value is removed. 61// 62// This Windows version takes and returns a Windows-style environment block 63// which is a concatenated list of null-terminated 16-bit strings. The end is 64// marked by a double-null terminator. The size of the returned string will 65// include the terminators. 66BASE_EXPORT string16 AlterEnvironment(const wchar_t* env, 67 const EnvironmentMap& changes); 68 69#elif defined(OS_POSIX) 70 71typedef std::string NativeEnvironmentString; 72typedef std::map<NativeEnvironmentString, NativeEnvironmentString> 73 EnvironmentMap; 74 75// See general comments for the Windows version above. 76// 77// This Posix version takes and returns a Posix-style environment block, which 78// is a null-terminated list of pointers to null-terminated strings. The 79// returned array will have appended to it the storage for the array itself so 80// there is only one pointer to manage, but this means that you can't copy the 81// array without keeping the original around. 82BASE_EXPORT scoped_ptr<char*[]> AlterEnvironment( 83 const char* const* env, 84 const EnvironmentMap& changes); 85 86#endif 87 88} // namespace base 89 90#endif // BASE_ENVIRONMENT_H_ 91