base/command_line.h

// Copyright (c) 2006-2008 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.

// This file contains a class that can be used to extract the salient
// elements of a command line in a relatively lightweight manner.
// Switches can optionally have a value attached using an equals sign,
// as in "-switch=value".  Arguments that aren't prefixed with a
// switch prefix are considered "loose parameters".  Switch names
// are case-insensitive.  An argument of "--" will terminate switch parsing,
// causing everything after to be considered as loose parameters.

#ifndef BASE_COMMAND_LINE_H_
#define BASE_COMMAND_LINE_H_

#include <map>
#include <string>
#include <vector>

#include "base/basictypes.h"
#include "base/scoped_ptr.h"

class CommandLine {
 public:
  // Creates a parsed version of the command line used to launch
  // the current process.
  CommandLine();

#if defined(OS_WIN)
  // Creates a parsed version of the given command-line string.
  // The program name is assumed to be the first item in the string.  
  CommandLine(const std::wstring& command_line);
#elif defined(OS_POSIX)
  CommandLine(int argc, const char* const* argv);
  CommandLine(const std::vector<std::string>& argv);
#endif

  ~CommandLine();

  // On non-Windows platforms, main() must call SetArgcArgv() before accessing
  // any members of this class.
  // On Windows, this call is a no-op (we instead parse GetCommandLineW()
  // directly) because we don't trust the CRT's parsing of the command line.
  static void SetArgcArgv(int argc, const char* const* argv);

  // Returns true if this command line contains the given switch.
  // (Switch names are case-insensitive.)
  bool HasSwitch(const std::wstring& switch_string) const;

  // Returns the value associated with the given switch.  If the
  // switch has no value or isn't present, this method returns
  // the empty string.
  std::wstring GetSwitchValue(const std::wstring& switch_string) const;

  // Returns the number of "loose values" found in the command line.
  // Loose values are arguments that aren't switches.
  // (The program name is also excluded from the set of loose values.)
  size_t GetLooseValueCount() const;

  typedef std::vector<std::wstring>::const_iterator LooseValueIterator;

  // Returns a const_iterator to the list of loose values.
  LooseValueIterator GetLooseValuesBegin() const;

  // Returns the end const_iterator for the list of loose values.
  LooseValueIterator GetLooseValuesEnd() const;

  // Simply returns the original command line string.
  std::wstring command_line_string() const;

#if defined(OS_POSIX)
  // Returns the original command line string as a vector of strings.
  const std::vector<std::string>& argv() const;
#endif

  // Returns the program part of the command line string (the first item).
  std::wstring program() const;

  // An array containing the prefixes that identify an argument as
  // a switch.
  static const wchar_t* const kSwitchPrefixes[];

  // The string that's used to separate switches from their values.
  static const wchar_t kSwitchValueSeparator[];

  // Treat everything after this argument as loose parameters.
  static const wchar_t kSwitchTerminator[];

  // Return a copy of the string prefixed with a switch prefix.
  // Used internally.
  static std::wstring PrefixedSwitchString(const std::wstring& switch_string);

  // Return a copy of the string prefixed with a switch prefix,
  // and appended with the given value. Used internally.
  static std::wstring PrefixedSwitchStringWithValue(
                        const std::wstring& switch_string,
                        const std::wstring& value_string);

  // Appends the given switch string (preceded by a space and a switch
  // prefix) to the given string.
  static void AppendSwitch(std::wstring* command_line_string,
                           const std::wstring& switch_string);

  // Appends the given switch string (preceded by a space and a switch
  // prefix) to the given string, with the given value attached.
  static void AppendSwitchWithValue(std::wstring* command_line_string,
                                    const std::wstring& switch_string,
                                    const std::wstring& value_string);

 private:
  class Data;

  // True if we are responsible for deleting our |data_| pointer.  In some cases
  // we cache the result of parsing the command line and |data_|'s lifetime is
  // managed by someone else (e.g., the |Singleton| class).
  bool we_own_data_;

  // A pointer to the parsed version of the command line.
  Data* data_;
  
  DISALLOW_EVIL_CONSTRUCTORS(CommandLine);
};

#endif  // BASE_COMMAND_LINE_H_