base: Add SetEnv() to EnvVarGetter class and get rid of the some ifdefs.

base/env_var.cc

 // Copyright (c) 2010 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.
 
 #include "base/env_var.h"
 
 #if defined(OS_POSIX)
 #include <stdlib.h>
 #elif defined(OS_WIN)
 #include <windows.h>
 #endif
 
 #include "base/string_util.h"
 
 #if defined(OS_WIN)
 #include "base/scoped_ptr.h"
 #include "base/utf_string_conversions.h"
 #endif
 
 namespace {
 
-class EnvVarGetterImpl
-    : public base::EnvVarGetter {
+class EnvVarGetterImpl : public base::EnvVarGetter {
  public:
   virtual bool GetEnv(const char* variable_name, std::string* result) {
     if (GetEnvImpl(variable_name, result))
       return true;
 
     // Some commonly used variable names are uppercase while others
     // are lowercase, which is inconsistent. Let's try to be helpful
     // and look for a variable name with the reverse case.
     // I.e. HTTP_PROXY may be http_proxy for some users/systems.
     char first_char = variable_name[0];
     std::string alternate_case_var;
     if (first_char >= 'a' && first_char <= 'z')
       alternate_case_var = StringToUpperASCII(std::string(variable_name));
     else if (first_char >= 'A' && first_char <= 'Z')
       alternate_case_var = StringToLowerASCII(std::string(variable_name));
     else
       return false;
     return GetEnvImpl(alternate_case_var.c_str(), result);
   }
+
+  virtual void SetEnv(const char* variable_name, const std::string& new_value) {
+    SetEnvImpl(variable_name, new_value);
+  }
+
  private:
   bool GetEnvImpl(const char* variable_name, std::string* result) {
 #if defined(OS_POSIX)
     const char* env_value = getenv(variable_name);
     if (!env_value)
       return false;
     // Note that the variable may be defined but empty.
     if (result)
       *result = env_value;
     return true;
 #elif defined(OS_WIN)
     DWORD value_length = ::GetEnvironmentVariable(
         UTF8ToWide(variable_name).c_str(), NULL, 0);
     if (value_length == 0)
       return false;
     if (result) {
       scoped_array<wchar_t> value(new wchar_t[value_length]);
       ::GetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), value.get(),
                                value_length);
       *result = WideToUTF8(value.get());
     }
     return true;
 #else
 #error need to port
 #endif
   }
+
+  void SetEnvImpl(const char* variable_name, const std::string& new_value) {
+#if defined(OS_POSIX)
+    setenv(variable_name, new_value.c_str(), 1);
+#elif defined(OS_WIN)
+    ::SetEnvironmentVariable(ASCIIToWide(variable_name).c_str(),
+                             ASCIIToWide(new_value).c_str());
+#endif
+  }
 };
 
 }  // namespace
 
 namespace base {
 
 // static
 EnvVarGetter* EnvVarGetter::Create() {
   return new EnvVarGetterImpl();
 }
 
 }  // namespace base