environment_internal.cc | Explore in Territory

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40284755): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif

#include "base/process/environment_internal.h"

#include <stddef.h>

#include <vector>

#include "build/build_config.h"

#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
#include <string.h>
#endif

#if BUILDFLAG(IS_WIN)
#include "base/check_op.h"
#endif

namespace base {
namespace internal {

namespace {

#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA) || BUILDFLAG(IS_WIN)
// 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) { … }
#endif

}  // namespace

#if BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)

base::HeapArray<char*> AlterEnvironment(const char* const* const env,
                                        const EnvironmentMap& changes) { … }

#elif BUILDFLAG(IS_WIN)

NativeEnvironmentString AlterEnvironment(const wchar_t* env,
                                         const EnvironmentMap& changes) {
  NativeEnvironmentString result;

  // First build up all of the unchanged environment strings.
  const wchar_t* ptr = env;
  while (*ptr) {
    std::wstring key;
    size_t line_length = ParseEnvLine(ptr, &key);

    // Keep only values not specified in the change vector.
    if (changes.find(key) == changes.end()) {
      result.append(ptr, line_length);
    }
    ptr += line_length;
  }

  // Now append all modified and new values.
  for (const auto& i : changes) {
    // Windows environment blocks cannot handle keys or values with NULs.
    CHECK_EQ(std::wstring::npos, i.first.find(L'\0'));
    CHECK_EQ(std::wstring::npos, i.second.find(L'\0'));
    if (!i.second.empty()) {
      result += i.first;
      result.push_back('=');
      result += i.second;
      result.push_back('\0');
    }
  }

  // Add the terminating NUL.
  result.push_back('\0');
  return result;
}

#endif  // BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)

}  // namespace internal
}  // namespace base
chromium/base/process/environment_internal.cc
