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// 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 "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_WIN)
#include <windows.h>
#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
#include <stdlib.h>
#endif
namespace base {
namespace {
class EnvironmentImpl : public Environment {
public:
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, result);
}
bool SetVar(StringPiece variable_name,
const std::string& new_value) override {
return SetVarImpl(variable_name, new_value);
}
bool UnSetVar(StringPiece variable_name) override {
return UnSetVarImpl(variable_name);
}
private:
bool GetVarImpl(StringPiece variable_name, std::string* result) {
#if defined(OS_WIN)
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;
#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
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;
#endif
}
bool SetVarImpl(StringPiece variable_name, const std::string& new_value) {
#if defined(OS_WIN)
// On success, a nonzero value is returned.
return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(),
UTF8ToWide(new_value).c_str());
#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
// On success, zero is returned.
return !setenv(variable_name.data(), new_value.c_str(), 1);
#endif
}
bool UnSetVarImpl(StringPiece variable_name) {
#if defined(OS_WIN)
// On success, a nonzero value is returned.
return !!SetEnvironmentVariable(UTF8ToWide(variable_name).c_str(), nullptr);
#elif defined(OS_POSIX) || defined(OS_FUCHSIA)
// On success, zero is returned.
return !unsetenv(variable_name.data());
#endif
}
};
} // namespace
namespace env_vars {
#if defined(OS_POSIX) || defined(OS_FUCHSIA)
// 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() = default;
// static
std::unique_ptr<Environment> Environment::Create() {
return std::make_unique<EnvironmentImpl>();
}
bool Environment::HasVar(StringPiece variable_name) {
return GetVar(variable_name, nullptr);
}
} // namespace base
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