Make base::Environment::Create() return unique_ptrs.

base/environment.cc

 // Copyright (c) 2012 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/environment.h"
 
 #include <stddef.h>
 
 #include <vector>
 
+#include "base/memory/ptr_util.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 
 #if defined(OS_POSIX)
 #include <stdlib.h>
 #elif defined(OS_WIN)
 #include <windows.h>
 #endif
 
 namespace base {
 
 namespace {
 
 class EnvironmentImpl : public Environment {
  public:
-  bool GetVar(const char* variable_name, std::string* result) override {
+  bool GetVar(StringPiece variable_name, std::string* result) override {
     if (GetVarImpl(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 (IsAsciiLower(first_char))
       alternate_case_var = ToUpperASCII(variable_name);
     else if (IsAsciiUpper(first_char))
       alternate_case_var = ToLowerASCII(variable_name);
     else
       return false;
     return GetVarImpl(alternate_case_var.c_str(), result);
   }
 
-  bool SetVar(const char* variable_name,
+  bool SetVar(StringPiece variable_name,
               const std::string& new_value) override {
     return SetVarImpl(variable_name, new_value);
   }
 
-  bool UnSetVar(const char* variable_name) override {
+  bool UnSetVar(StringPiece variable_name) override {
     return UnSetVarImpl(variable_name);
   }
 
  private:
-  bool GetVarImpl(const char* variable_name, std::string* result) {
+  bool GetVarImpl(StringPiece variable_name, std::string* result) {
 #if defined(OS_POSIX)
-    const char* env_value = getenv(variable_name);
+    const char* env_value = getenv(variable_name.data());
     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);
+    DWORD value_length =
+        ::GetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), nullptr, 0);
     if (value_length == 0)
       return false;
     if (result) {
       std::unique_ptr<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
   }
 
-  bool SetVarImpl(const char* variable_name, const std::string& new_value) {
+  bool SetVarImpl(StringPiece 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);
+    return !setenv(variable_name.data(), new_value.c_str(), 1);
 #elif defined(OS_WIN)
     // On success, a nonzero value is returned.
     return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(),
                                     UTF8ToWide(new_value).c_str());
 #endif
   }
 
-  bool UnSetVarImpl(const char* variable_name) {
+  bool UnSetVarImpl(StringPiece variable_name) {
 #if defined(OS_POSIX)
     // On success, zero is returned.
-    return !unsetenv(variable_name);
+    return !unsetenv(variable_name.data());
 #elif defined(OS_WIN)
     // On success, a nonzero value is returned.
-    return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), NULL);
+    return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), nullptr);
 #endif
   }
 };
 
 // Parses a null-terminated input string of an environment block. The key is
 // placed into the given string, and the total length of the line, including
 // the terminating null, is returned.
 size_t ParseEnvLine(const NativeEnvironmentString::value_type* input,
                     NativeEnvironmentString* key) {
   // Skip to the equals or end of the string, this is the key.
@@ skipping 16 matching lines @@
 // 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
 
 Environment::~Environment() {}
 
 // static
-Environment* Environment::Create() {
-  return new EnvironmentImpl();
+std::unique_ptr<Environment> Environment::Create() {
+  return MakeUnique<EnvironmentImpl>();
 }
 
-bool Environment::HasVar(const char* variable_name) {
-  return GetVar(variable_name, NULL);
+bool Environment::HasVar(StringPiece variable_name) {
+  return GetVar(variable_name, nullptr);
 }
 
 #if defined(OS_WIN)
 
 string16 AlterEnvironment(const wchar_t* env,
                           const EnvironmentMap& changes) {
   string16 result;
 
   // First copy all unmodified values to the output.
   size_t cur_env = 0;
@@ skipping 77 matching lines @@
   for (size_t i = 0; i < result_indices.size(); i++)
     result[i] = &storage_data[result_indices[i]];
   result[result_indices.size()] = 0;  // Null terminator.
 
   return result;
 }
 
 #endif  // OS_POSIX
 
 }  // namespace base