1 // Copyright (c) 2012 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 #include "base/memory/ptr_util.h"
8 #include "base/strings/string_piece.h"
9 #include "base/strings/string_util.h"
10 #include "base/strings/utf_string_conversions.h"
11 #include "build/build_config.h"
12
13 #if defined(OS_WIN)
14 #include <windows.h>
15 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
16 #include <stdlib.h>
17 #endif
18
19 namespace base {
20
21 namespace {
22
23 class EnvironmentImpl : public Environment {
24 public:
GetVar(StringPiece variable_name,std::string * result)25 bool GetVar(StringPiece variable_name, std::string* result) override {
26 if (GetVarImpl(variable_name, result))
27 return true;
28
29 // Some commonly used variable names are uppercase while others
30 // are lowercase, which is inconsistent. Let's try to be helpful
31 // and look for a variable name with the reverse case.
32 // I.e. HTTP_PROXY may be http_proxy for some users/systems.
33 char first_char = variable_name[0];
34 std::string alternate_case_var;
35 if (IsAsciiLower(first_char))
36 alternate_case_var = ToUpperASCII(variable_name);
37 else if (IsAsciiUpper(first_char))
38 alternate_case_var = ToLowerASCII(variable_name);
39 else
40 return false;
41 return GetVarImpl(alternate_case_var, result);
42 }
43
SetVar(StringPiece variable_name,const std::string & new_value)44 bool SetVar(StringPiece variable_name,
45 const std::string& new_value) override {
46 return SetVarImpl(variable_name, new_value);
47 }
48
UnSetVar(StringPiece variable_name)49 bool UnSetVar(StringPiece variable_name) override {
50 return UnSetVarImpl(variable_name);
51 }
52
53 private:
GetVarImpl(StringPiece variable_name,std::string * result)54 bool GetVarImpl(StringPiece variable_name, std::string* result) {
55 #if defined(OS_WIN)
56 DWORD value_length =
57 ::GetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), nullptr, 0);
58 if (value_length == 0)
59 return false;
60 if (result) {
61 std::unique_ptr<wchar_t[]> value(new wchar_t[value_length]);
62 ::GetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), value.get(),
63 value_length);
64 *result = WideToUTF8(value.get());
65 }
66 return true;
67 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
68 const char* env_value = getenv(variable_name.data());
69 if (!env_value)
70 return false;
71 // Note that the variable may be defined but empty.
72 if (result)
73 *result = env_value;
74 return true;
75 #endif
76 }
77
SetVarImpl(StringPiece variable_name,const std::string & new_value)78 bool SetVarImpl(StringPiece variable_name, const std::string& new_value) {
79 #if defined(OS_WIN)
80 // On success, a nonzero value is returned.
81 return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(),
82 UTF8ToWide(new_value).c_str());
83 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
84 // On success, zero is returned.
85 return !setenv(variable_name.data(), new_value.c_str(), 1);
86 #endif
87 }
88
UnSetVarImpl(StringPiece variable_name)89 bool UnSetVarImpl(StringPiece variable_name) {
90 #if defined(OS_WIN)
91 // On success, a nonzero value is returned.
92 return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), nullptr);
93 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
94 // On success, zero is returned.
95 return !unsetenv(variable_name.data());
96 #endif
97 }
98 };
99
100 } // namespace
101
102 namespace env_vars {
103
104 #if defined(OS_POSIX) || defined(OS_FUCHSIA)
105 // On Posix systems, this variable contains the location of the user's home
106 // directory. (e.g, /home/username/).
107 const char kHome[] = "HOME";
108 #endif
109
110 } // namespace env_vars
111
112 Environment::~Environment() = default;
113
114 // static
Create()115 std::unique_ptr<Environment> Environment::Create() {
116 return std::make_unique<EnvironmentImpl>();
117 }
118
HasVar(StringPiece variable_name)119 bool Environment::HasVar(StringPiece variable_name) {
120 return GetVar(variable_name, nullptr);
121 }
122
123 } // namespace base
124