The Tor Browser / file revision

 // Copyright (c) 2011 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_ENVIRONMENT_H_

 #define BASE_ENVIRONMENT_H_

 #include <map>

 #include <string>

 #include "base/base_export.h"

 #include "base/memory/scoped_ptr.h"

 #include "base/strings/string16.h"

 #include "build/build_config.h"

 namespace base {

 namespace env_vars {

 #if defined(OS_POSIX)

 BASE_EXPORT extern const char kHome[];

 #endif

 }  // namespace env_vars

 class BASE_EXPORT Environment {

  public:

   virtual ~Environment();

   // Static factory method that returns the implementation that provide the

   // appropriate platform-specific instance.

   static Environment* Create();

   // Gets an environment variable's value and stores it in |result|.

   // Returns false if the key is unset.

   virtual bool GetVar(const char* variable_name, std::string* result) = 0;

   // Syntactic sugar for GetVar(variable_name, NULL);

   virtual bool HasVar(const char* variable_name);

   // Returns true on success, otherwise returns false.

   virtual bool SetVar(const char* variable_name,

                       const std::string& new_value) = 0;

   // Returns true on success, otherwise returns false.

   virtual bool UnSetVar(const char* variable_name) = 0;

 };

 #if defined(OS_WIN)

 typedef string16 NativeEnvironmentString;

 typedef std::map<NativeEnvironmentString, NativeEnvironmentString>

     EnvironmentMap;

 // Returns a modified environment vector constructed from the given environment

 // and the list of changes given in |changes|. Each key in the environment is

 // matched against the first element of the pairs. In the event of a match, the

 // value is replaced by the second of the pair, unless the second is empty, in

 // which case the key-value is removed.

 //

 // This Windows version takes and returns a Windows-style environment block

 // which is a concatenated list of null-terminated 16-bit strings. The end is

 // marked by a double-null terminator. The size of the returned string will

 // include the terminators.

 BASE_EXPORT string16 AlterEnvironment(const wchar_t* env,

                                       const EnvironmentMap& changes);

 #elif defined(OS_POSIX)

 typedef std::string NativeEnvironmentString;

 typedef std::map<NativeEnvironmentString, NativeEnvironmentString>

     EnvironmentMap;

 // See general comments for the Windows version above.

 //

 // This Posix version takes and returns a Posix-style environment block, which

 // is a null-terminated list of pointers to null-terminated strings. The

 // returned array will have appended to it the storage for the array itself so

 // there is only one pointer to manage, but this means that you can't copy the

 // array without keeping the original around.

 BASE_EXPORT scoped_ptr<char*[]> AlterEnvironment(

     const char* const* env,

     const EnvironmentMap& changes);

 #endif

 }  // namespace base

 #endif  // BASE_ENVIRONMENT_H_