root/base/command_line.cc

DEFINITIONS

1. GetSwitchPrefixLength
2. IsSwitch
3. AppendSwitchesAndArguments
4. LowerASCIIOnWindows
5. QuoteForCommandLineToArgvW
6. begin_args_
7. begin_args_
8. begin_args_
9. begin_args_
10. set_slash_is_not_a_switch
11. Init
12. Reset
13. ForCurrentProcess
14. InitializedForCurrentProcess
15. FromString
16. InitFromArgv
17. InitFromArgv
18. GetCommandLineString
19. GetArgumentsString
20. GetProgram
21. SetProgram
22. HasSwitch
23. GetSwitchValueASCII
24. GetSwitchValuePath
25. GetSwitchValueNative
26. AppendSwitch
27. AppendSwitchPath
28. AppendSwitchNative
29. AppendSwitchASCII
30. CopySwitchesFrom
31. GetArgs
32. AppendArg
33. AppendArgPath
34. AppendArgNative
35. AppendArguments
36. PrependWrapper
37. ParseFromString

// 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/command_line.h"

#include <algorithm>
#include <ostream>

#include "base/basictypes.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/strings/string_split.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>
#include <shellapi.h>
#endif

namespace base {

CommandLine* CommandLine::current_process_commandline_ = NULL;

namespace {

const CommandLine::CharType kSwitchTerminator[] = FILE_PATH_LITERAL("--");
const CommandLine::CharType kSwitchValueSeparator[] = FILE_PATH_LITERAL("=");

// Since we use a lazy match, make sure that longer versions (like "--") are
// listed before shorter versions (like "-") of similar prefixes.
#if defined(OS_WIN)
// By putting slash last, we can control whether it is treaded as a switch
// value by changing the value of switch_prefix_count to be one less than
// the array size.
const CommandLine::CharType* const kSwitchPrefixes[] = {L"--", L"-", L"/"};
#elif defined(OS_POSIX)
// Unixes don't use slash as a switch.
const CommandLine::CharType* const kSwitchPrefixes[] = {"--", "-"};
#endif
size_t switch_prefix_count = arraysize(kSwitchPrefixes);

size_t GetSwitchPrefixLength(const CommandLine::StringType& string) {
  for (size_t i = 0; i < switch_prefix_count; ++i) {
    CommandLine::StringType prefix(kSwitchPrefixes[i]);
    if (string.compare(0, prefix.length(), prefix) == 0)
      return prefix.length();
  }
  return 0;
}

// Fills in |switch_string| and |switch_value| if |string| is a switch.
// This will preserve the input switch prefix in the output |switch_string|.
bool IsSwitch(const CommandLine::StringType& string,
              CommandLine::StringType* switch_string,
              CommandLine::StringType* switch_value) {
  switch_string->clear();
  switch_value->clear();
  size_t prefix_length = GetSwitchPrefixLength(string);
  if (prefix_length == 0 || prefix_length == string.length())
    return false;

  const size_t equals_position = string.find(kSwitchValueSeparator);
  *switch_string = string.substr(0, equals_position);
  if (equals_position != CommandLine::StringType::npos)
    *switch_value = string.substr(equals_position + 1);
  return true;
}

// Append switches and arguments, keeping switches before arguments.
void AppendSwitchesAndArguments(CommandLine& command_line,
                                const CommandLine::StringVector& argv) {
  bool parse_switches = true;
  for (size_t i = 1; i < argv.size(); ++i) {
    CommandLine::StringType arg = argv[i];
    TrimWhitespace(arg, TRIM_ALL, &arg);

    CommandLine::StringType switch_string;
    CommandLine::StringType switch_value;
    parse_switches &= (arg != kSwitchTerminator);
    if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
#if defined(OS_WIN)
      command_line.AppendSwitchNative(UTF16ToASCII(switch_string),
                                      switch_value);
#elif defined(OS_POSIX)
      command_line.AppendSwitchNative(switch_string, switch_value);
#endif
    } else {
      command_line.AppendArgNative(arg);
    }
  }
}

// Lowercase switches for backwards compatiblity *on Windows*.
std::string LowerASCIIOnWindows(const std::string& string) {
#if defined(OS_WIN)
  return StringToLowerASCII(string);
#elif defined(OS_POSIX)
  return string;
#endif
}


#if defined(OS_WIN)
// Quote a string as necessary for CommandLineToArgvW compatiblity *on Windows*.
std::wstring QuoteForCommandLineToArgvW(const std::wstring& arg) {
  // We follow the quoting rules of CommandLineToArgvW.
  // http://msdn.microsoft.com/en-us/library/17w5ykft.aspx
  if (arg.find_first_of(L" \\\"") == std::wstring::npos) {
    // No quoting necessary.
    return arg;
  }

  std::wstring out;
  out.push_back(L'"');
  for (size_t i = 0; i < arg.size(); ++i) {
    if (arg[i] == '\\') {
      // Find the extent of this run of backslashes.
      size_t start = i, end = start + 1;
      for (; end < arg.size() && arg[end] == '\\'; ++end)
        /* empty */;
      size_t backslash_count = end - start;

      // Backslashes are escapes only if the run is followed by a double quote.
      // Since we also will end the string with a double quote, we escape for
      // either a double quote or the end of the string.
      if (end == arg.size() || arg[end] == '"') {
        // To quote, we need to output 2x as many backslashes.
        backslash_count *= 2;
      }
      for (size_t j = 0; j < backslash_count; ++j)
        out.push_back('\\');

      // Advance i to one before the end to balance i++ in loop.
      i = end - 1;
    } else if (arg[i] == '"') {
      out.push_back('\\');
      out.push_back('"');
    } else {
      out.push_back(arg[i]);
    }
  }
  out.push_back('"');

  return out;
}
#endif

}  // namespace

CommandLine::CommandLine(NoProgram no_program)
    : argv_(1),
      begin_args_(1) {
}

CommandLine::CommandLine(const FilePath& program)
    : argv_(1),
      begin_args_(1) {
  SetProgram(program);
}

CommandLine::CommandLine(int argc, const CommandLine::CharType* const* argv)
    : argv_(1),
      begin_args_(1) {
  InitFromArgv(argc, argv);
}

CommandLine::CommandLine(const StringVector& argv)
    : argv_(1),
      begin_args_(1) {
  InitFromArgv(argv);
}

CommandLine::~CommandLine() {
}

#if defined(OS_WIN)
// static
void CommandLine::set_slash_is_not_a_switch() {
  // The last switch prefix should be slash, so adjust the size to skip it.
  DCHECK(wcscmp(kSwitchPrefixes[arraysize(kSwitchPrefixes) - 1], L"/") == 0);
  switch_prefix_count = arraysize(kSwitchPrefixes) - 1;
}
#endif

// static
bool CommandLine::Init(int argc, const char* const* argv) {
  if (current_process_commandline_) {
    // If this is intentional, Reset() must be called first. If we are using
    // the shared build mode, we have to share a single object across multiple
    // shared libraries.
    return false;
  }

  current_process_commandline_ = new CommandLine(NO_PROGRAM);
#if defined(OS_WIN)
  current_process_commandline_->ParseFromString(::GetCommandLineW());
#elif defined(OS_POSIX)
  current_process_commandline_->InitFromArgv(argc, argv);
#endif

  return true;
}

// static
void CommandLine::Reset() {
  DCHECK(current_process_commandline_);
  delete current_process_commandline_;
  current_process_commandline_ = NULL;
}

// static
CommandLine* CommandLine::ForCurrentProcess() {
  DCHECK(current_process_commandline_);
  return current_process_commandline_;
}

// static
bool CommandLine::InitializedForCurrentProcess() {
  return !!current_process_commandline_;
}

#if defined(OS_WIN)
// static
CommandLine CommandLine::FromString(const std::wstring& command_line) {
  CommandLine cmd(NO_PROGRAM);
  cmd.ParseFromString(command_line);
  return cmd;
}
#endif

void CommandLine::InitFromArgv(int argc,
                               const CommandLine::CharType* const* argv) {
  StringVector new_argv;
  for (int i = 0; i < argc; ++i)
    new_argv.push_back(argv[i]);
  InitFromArgv(new_argv);
}

void CommandLine::InitFromArgv(const StringVector& argv) {
  argv_ = StringVector(1);
  switches_.clear();
  begin_args_ = 1;
  SetProgram(argv.empty() ? FilePath() : FilePath(argv[0]));
  AppendSwitchesAndArguments(*this, argv);
}

CommandLine::StringType CommandLine::GetCommandLineString() const {
  StringType string(argv_[0]);
#if defined(OS_WIN)
  string = QuoteForCommandLineToArgvW(string);
#endif
  StringType params(GetArgumentsString());
  if (!params.empty()) {
    string.append(StringType(FILE_PATH_LITERAL(" ")));
    string.append(params);
  }
  return string;
}

CommandLine::StringType CommandLine::GetArgumentsString() const {
  StringType params;
  // Append switches and arguments.
  bool parse_switches = true;
  for (size_t i = 1; i < argv_.size(); ++i) {
    StringType arg = argv_[i];
    StringType switch_string;
    StringType switch_value;
    parse_switches &= arg != kSwitchTerminator;
    if (i > 1)
      params.append(StringType(FILE_PATH_LITERAL(" ")));
    if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
      params.append(switch_string);
      if (!switch_value.empty()) {
#if defined(OS_WIN)
        switch_value = QuoteForCommandLineToArgvW(switch_value);
#endif
        params.append(kSwitchValueSeparator + switch_value);
      }
    }
    else {
#if defined(OS_WIN)
      arg = QuoteForCommandLineToArgvW(arg);
#endif
      params.append(arg);
    }
  }
  return params;
}

FilePath CommandLine::GetProgram() const {
  return FilePath(argv_[0]);
}

void CommandLine::SetProgram(const FilePath& program) {
  TrimWhitespace(program.value(), TRIM_ALL, &argv_[0]);
}

bool CommandLine::HasSwitch(const std::string& switch_string) const {
  return switches_.find(LowerASCIIOnWindows(switch_string)) != switches_.end();
}

std::string CommandLine::GetSwitchValueASCII(
    const std::string& switch_string) const {
  StringType value = GetSwitchValueNative(switch_string);
  if (!IsStringASCII(value)) {
    DLOG(WARNING) << "Value of switch (" << switch_string << ") must be ASCII.";
    return std::string();
  }
#if defined(OS_WIN)
  return UTF16ToASCII(value);
#else
  return value;
#endif
}

FilePath CommandLine::GetSwitchValuePath(
    const std::string& switch_string) const {
  return FilePath(GetSwitchValueNative(switch_string));
}

CommandLine::StringType CommandLine::GetSwitchValueNative(
    const std::string& switch_string) const {
  SwitchMap::const_iterator result =
    switches_.find(LowerASCIIOnWindows(switch_string));
  return result == switches_.end() ? StringType() : result->second;
}

void CommandLine::AppendSwitch(const std::string& switch_string) {
  AppendSwitchNative(switch_string, StringType());
}

void CommandLine::AppendSwitchPath(const std::string& switch_string,
                                   const FilePath& path) {
  AppendSwitchNative(switch_string, path.value());
}

void CommandLine::AppendSwitchNative(const std::string& switch_string,
                                     const CommandLine::StringType& value) {
  std::string switch_key(LowerASCIIOnWindows(switch_string));
#if defined(OS_WIN)
  StringType combined_switch_string(ASCIIToWide(switch_key));
#elif defined(OS_POSIX)
  StringType combined_switch_string(switch_string);
#endif
  size_t prefix_length = GetSwitchPrefixLength(combined_switch_string);
  switches_[switch_key.substr(prefix_length)] = value;
  // Preserve existing switch prefixes in |argv_|; only append one if necessary.
  if (prefix_length == 0)
    combined_switch_string = kSwitchPrefixes[0] + combined_switch_string;
  if (!value.empty())
    combined_switch_string += kSwitchValueSeparator + value;
  // Append the switch and update the switches/arguments divider |begin_args_|.
  argv_.insert(argv_.begin() + begin_args_++, combined_switch_string);
}

void CommandLine::AppendSwitchASCII(const std::string& switch_string,
                                    const std::string& value_string) {
#if defined(OS_WIN)
  AppendSwitchNative(switch_string, ASCIIToWide(value_string));
#elif defined(OS_POSIX)
  AppendSwitchNative(switch_string, value_string);
#endif
}

void CommandLine::CopySwitchesFrom(const CommandLine& source,
                                   const char* const switches[],
                                   size_t count) {
  for (size_t i = 0; i < count; ++i) {
    if (source.HasSwitch(switches[i]))
      AppendSwitchNative(switches[i], source.GetSwitchValueNative(switches[i]));
  }
}

CommandLine::StringVector CommandLine::GetArgs() const {
  // Gather all arguments after the last switch (may include kSwitchTerminator).
  StringVector args(argv_.begin() + begin_args_, argv_.end());
  // Erase only the first kSwitchTerminator (maybe "--" is a legitimate page?)
  StringVector::iterator switch_terminator =
      std::find(args.begin(), args.end(), kSwitchTerminator);
  if (switch_terminator != args.end())
    args.erase(switch_terminator);
  return args;
}

void CommandLine::AppendArg(const std::string& value) {
#if defined(OS_WIN)
  DCHECK(IsStringUTF8(value));
  AppendArgNative(UTF8ToWide(value));
#elif defined(OS_POSIX)
  AppendArgNative(value);
#endif
}

void CommandLine::AppendArgPath(const FilePath& path) {
  AppendArgNative(path.value());
}

void CommandLine::AppendArgNative(const CommandLine::StringType& value) {
  argv_.push_back(value);
}

void CommandLine::AppendArguments(const CommandLine& other,
                                  bool include_program) {
  if (include_program)
    SetProgram(other.GetProgram());
  AppendSwitchesAndArguments(*this, other.argv());
}

void CommandLine::PrependWrapper(const CommandLine::StringType& wrapper) {
  if (wrapper.empty())
    return;
  // The wrapper may have embedded arguments (like "gdb --args"). In this case,
  // we don't pretend to do anything fancy, we just split on spaces.
  StringVector wrapper_argv;
  SplitString(wrapper, FILE_PATH_LITERAL(' '), &wrapper_argv);
  // Prepend the wrapper and update the switches/arguments |begin_args_|.
  argv_.insert(argv_.begin(), wrapper_argv.begin(), wrapper_argv.end());
  begin_args_ += wrapper_argv.size();
}

#if defined(OS_WIN)
void CommandLine::ParseFromString(const std::wstring& command_line) {
  std::wstring command_line_string;
  TrimWhitespace(command_line, TRIM_ALL, &command_line_string);
  if (command_line_string.empty())
    return;

  int num_args = 0;
  wchar_t** args = NULL;
  args = ::CommandLineToArgvW(command_line_string.c_str(), &num_args);

  DPLOG_IF(FATAL, !args) << "CommandLineToArgvW failed on command line: "
                         << UTF16ToUTF8(command_line);
  InitFromArgv(num_args, args);
  LocalFree(args);
}
#endif

}  // namespace base