base: Add UnSetEnv function to EnvVarGetter API.

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>
@@ skipping 26 matching lines @@
       alternate_case_var = StringToLowerASCII(std::string(variable_name));
     else
       return false;
     return GetEnvImpl(alternate_case_var.c_str(), result);
   }
 
   virtual bool SetEnv(const char* variable_name, const std::string& new_value) {
     return SetEnvImpl(variable_name, new_value);
   }
 
+  virtual bool UnSetEnv(const char* variable_name) {
+    return UnSetEnvImpl(variable_name);
+  }
+
  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;
@@ skipping 17 matching lines @@
   bool SetEnvImpl(const char* variable_name, const std::string& new_value) {
 #if defined(OS_POSIX)
     // On success, zero is returned.
     return setenv(variable_name, new_value.c_str(), 1) == 0;
 #elif defined(OS_WIN)
     // On success, a nonzero is returned.
     return ::SetEnvironmentVariable(ASCIIToWide(variable_name).c_str(),
                                     ASCIIToWide(new_value).c_str()) != 0;
 #endif
   }
+
+  bool UnSetEnvImpl(const char* variable_name) {
+#if defined(OS_POSIX)
+    // On success, zero is returned.
+    return unsetenv(variable_name) == 0;
+#elif defined(OS_WIN)
+    // On success, a nonzero is returned.
+    return ::SetEnvironmentVariable(ASCIIToWide(variable_name).c_str(),
+                                    NULL) != 0;
+#endif
+  }
 };
 
 }  // namespace
 
 namespace base {
 
 namespace env_vars {
 
 #if defined(OS_POSIX)
 // On Posix systems, this variable contains the location of the user's home
 // directory. (e.g, /home/username/).
 const char kHome[] = "HOME";
 #endif
 
 }  // namespace env_vars
 
 EnvVarGetter::~EnvVarGetter() {}
 
-bool EnvVarGetter::HasEnv(const char* variable_name) {
-  return GetEnv(variable_name, NULL);
-}
-
 // static
 EnvVarGetter* EnvVarGetter::Create() {
   return new EnvVarGetterImpl();
 }
 
+bool EnvVarGetter::HasEnv(const char* variable_name) {
+  return GetEnv(variable_name, NULL);
+}
+
 }  // namespace base