michael@0: // Copyright (c) 2011 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef BASE_ENVIRONMENT_H_
michael@0: #define BASE_ENVIRONMENT_H_
michael@0: 
michael@0: #include <map>
michael@0: #include <string>
michael@0: 
michael@0: #include "base/base_export.h"
michael@0: #include "base/memory/scoped_ptr.h"
michael@0: #include "base/strings/string16.h"
michael@0: #include "build/build_config.h"
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: namespace env_vars {
michael@0: 
michael@0: #if defined(OS_POSIX)
michael@0: BASE_EXPORT extern const char kHome[];
michael@0: #endif
michael@0: 
michael@0: }  // namespace env_vars
michael@0: 
michael@0: class BASE_EXPORT Environment {
michael@0:  public:
michael@0:   virtual ~Environment();
michael@0: 
michael@0:   // Static factory method that returns the implementation that provide the
michael@0:   // appropriate platform-specific instance.
michael@0:   static Environment* Create();
michael@0: 
michael@0:   // Gets an environment variable's value and stores it in |result|.
michael@0:   // Returns false if the key is unset.
michael@0:   virtual bool GetVar(const char* variable_name, std::string* result) = 0;
michael@0: 
michael@0:   // Syntactic sugar for GetVar(variable_name, NULL);
michael@0:   virtual bool HasVar(const char* variable_name);
michael@0: 
michael@0:   // Returns true on success, otherwise returns false.
michael@0:   virtual bool SetVar(const char* variable_name,
michael@0:                       const std::string& new_value) = 0;
michael@0: 
michael@0:   // Returns true on success, otherwise returns false.
michael@0:   virtual bool UnSetVar(const char* variable_name) = 0;
michael@0: };
michael@0: 
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0: 
michael@0: typedef string16 NativeEnvironmentString;
michael@0: typedef std::map<NativeEnvironmentString, NativeEnvironmentString>
michael@0:     EnvironmentMap;
michael@0: 
michael@0: // Returns a modified environment vector constructed from the given environment
michael@0: // and the list of changes given in |changes|. Each key in the environment is
michael@0: // matched against the first element of the pairs. In the event of a match, the
michael@0: // value is replaced by the second of the pair, unless the second is empty, in
michael@0: // which case the key-value is removed.
michael@0: //
michael@0: // This Windows version takes and returns a Windows-style environment block
michael@0: // which is a concatenated list of null-terminated 16-bit strings. The end is
michael@0: // marked by a double-null terminator. The size of the returned string will
michael@0: // include the terminators.
michael@0: BASE_EXPORT string16 AlterEnvironment(const wchar_t* env,
michael@0:                                       const EnvironmentMap& changes);
michael@0: 
michael@0: #elif defined(OS_POSIX)
michael@0: 
michael@0: typedef std::string NativeEnvironmentString;
michael@0: typedef std::map<NativeEnvironmentString, NativeEnvironmentString>
michael@0:     EnvironmentMap;
michael@0: 
michael@0: // See general comments for the Windows version above.
michael@0: //
michael@0: // This Posix version takes and returns a Posix-style environment block, which
michael@0: // is a null-terminated list of pointers to null-terminated strings. The
michael@0: // returned array will have appended to it the storage for the array itself so
michael@0: // there is only one pointer to manage, but this means that you can't copy the
michael@0: // array without keeping the original around.
michael@0: BASE_EXPORT scoped_ptr<char*[]> AlterEnvironment(
michael@0:     const char* const* env,
michael@0:     const EnvironmentMap& changes);
michael@0: 
michael@0: #endif
michael@0: 
michael@0: }  // namespace base
michael@0: 
michael@0: #endif  // BASE_ENVIRONMENT_H_