base/environment.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/environment.h"
   6
   7 #if defined(OS_POSIX)
   8 #include <stdlib.h>
   9 #elif defined(OS_WIN)
  10 #include <windows.h>
  11 #endif
  12
  13 #include "base/string_util.h"
  14
  15 #if defined(OS_WIN)
  16 #include "base/memory/scoped_ptr.h"
  17 #include "base/utf_string_conversions.h"
  18 #endif
  19
  20 namespace {
  21
  22 class EnvironmentImpl : public base::Environment {
  23  public:
  24   virtual bool GetVar(const char* variable_name, std::string* result) {
  25     if (GetVarImpl(variable_name, result))
  26       return true;
  27
  28     // Some commonly used variable names are uppercase while others
  29     // are lowercase, which is inconsistent. Let's try to be helpful
  30     // and look for a variable name with the reverse case.
  31     // I.e. HTTP_PROXY may be http_proxy for some users/systems.
  32     char first_char = variable_name[0];
  33     std::string alternate_case_var;
  34     if (first_char >= 'a' && first_char <= 'z')
  35       alternate_case_var = StringToUpperASCII(std::string(variable_name));
  36     else if (first_char >= 'A' && first_char <= 'Z')
  37       alternate_case_var = StringToLowerASCII(std::string(variable_name));
  38     else
  39       return false;
  40     return GetVarImpl(alternate_case_var.c_str(), result);
  41   }
  42
  43   virtual bool SetVar(const char* variable_name, const std::string& new_value) {
  44     return SetVarImpl(variable_name, new_value);
  45   }
  46
  47   virtual bool UnSetVar(const char* variable_name) {
  48     return UnSetVarImpl(variable_name);
  49   }
  50
  51  private:
  52   bool GetVarImpl(const char* variable_name, std::string* result) {
  53 #if defined(OS_POSIX)
  54     const char* env_value = getenv(variable_name);
  55     if (!env_value)
  56       return false;
  57     // Note that the variable may be defined but empty.
  58     if (result)
  59       *result = env_value;
  60     return true;
  61 #elif defined(OS_WIN)
  62     DWORD value_length = ::GetEnvironmentVariable(
  63         UTF8ToWide(variable_name).c_str(), NULL, 0);
  64     if (value_length == 0)
  65       return false;
  66     if (result) {
  67       scoped_array<wchar_t> value(new wchar_t[value_length]);
  68       ::GetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), value.get(),
  69                                value_length);
  70       *result = WideToUTF8(value.get());
  71     }
  72     return true;
  73 #else
  74 #error need to port
  75 #endif
  76   }
  77
  78   bool SetVarImpl(const char* variable_name, const std::string& new_value) {
  79 #if defined(OS_POSIX)
  80     // On success, zero is returned.
  81     return !setenv(variable_name, new_value.c_str(), 1);
  82 #elif defined(OS_WIN)
  83     // On success, a nonzero value is returned.
  84     return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(),
  85                                     UTF8ToWide(new_value).c_str());
  86 #endif
  87   }
  88
  89   bool UnSetVarImpl(const char* variable_name) {
  90 #if defined(OS_POSIX)
  91     // On success, zero is returned.
  92     return !unsetenv(variable_name);
  93 #elif defined(OS_WIN)
  94     // On success, a nonzero value is returned.
  95     return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), NULL);
  96 #endif
  97   }
  98 };
  99
 100 }  // namespace
 101
 102 namespace base {
 103
 104 namespace env_vars {
 105
 106 #if defined(OS_POSIX)
 107 // On Posix systems, this variable contains the location of the user's home
 108 // directory. (e.g, /home/username/).
 109 const char kHome[] = "HOME";
 110 #endif
 111
 112 }  // namespace env_vars
 113
 114 Environment::~Environment() {}
 115
 116 // static
 117 Environment* Environment::Create() {
 118   return new EnvironmentImpl();
 119 }
 120
 121 bool Environment::HasVar(const char* variable_name) {
 122   return GetVar(variable_name, NULL);
 123 }
 124
 125 }  // namespace base