base/command_line.h

   1 // Copyright (c) 2011 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 // This class works with command lines: building and parsing.
   6 // Switches can optionally have a value attached using an equals sign, as in
   7 // "-switch=value". Arguments that aren't prefixed with a switch prefix are
   8 // saved as extra arguments. An argument of "--" will terminate switch parsing,
   9 // causing everything after to be considered as extra arguments.
  10
  11 // There is a singleton read-only CommandLine that represents the command line
  12 // that the current process was started with.  It must be initialized in main().
  13
  14 #ifndef BASE_COMMAND_LINE_H_
  15 #define BASE_COMMAND_LINE_H_
  16 #pragma once
  17
  18 #include <stddef.h>
  19 #include <map>
  20 #include <string>
  21 #include <vector>
  22
  23 #include "base/base_api.h"
  24 #include "build/build_config.h"
  25
  26 class FilePath;
  27
  28 class BASE_API CommandLine {
  29  public:
  30 #if defined(OS_WIN)
  31   // The native command line string type.
  32   typedef std::wstring StringType;
  33 #elif defined(OS_POSIX)
  34   typedef std::string StringType;
  35 #endif
  36
  37   typedef std::vector<StringType> StringVector;
  38   // The type of map for parsed-out switch key and values.
  39   typedef std::map<std::string, StringType> SwitchMap;
  40
  41   // A constructor for CommandLines that only carry switches and arguments.
  42   enum NoProgram { NO_PROGRAM };
  43   explicit CommandLine(NoProgram no_program);
  44
  45   // Construct a new command line with |program| as argv[0].
  46   explicit CommandLine(const FilePath& program);
  47
  48 #if defined(OS_POSIX)
  49   CommandLine(int argc, const char* const* argv);
  50   explicit CommandLine(const StringVector& argv);
  51 #endif
  52
  53   ~CommandLine();
  54
  55   // Initialize the current process CommandLine singleton. On Windows, ignores
  56   // its arguments (we instead parse GetCommandLineW() directly) because we
  57   // don't trust the CRT's parsing of the command line, but it still must be
  58   // called to set up the command line.
  59   static void Init(int argc, const char* const* argv);
  60
  61   // Destroys the current process CommandLine singleton. This is necessary if
  62   // you want to reset the base library to its initial state (for example, in an
  63   // outer library that needs to be able to terminate, and be re-initialized).
  64   // If Init is called only once, as in main(), Reset() is not necessary.
  65   static void Reset();
  66
  67   // Get the singleton CommandLine representing the current process's
  68   // command line. Note: returned value is mutable, but not thread safe;
  69   // only mutate if you know what you're doing!
  70   static CommandLine* ForCurrentProcess();
  71
  72 #if defined(OS_WIN)
  73   static CommandLine FromString(const std::wstring& command_line);
  74 #endif
  75
  76 #if defined(OS_POSIX)
  77   // Initialize from an argv vector.
  78   void InitFromArgv(int argc, const char* const* argv);
  79   void InitFromArgv(const StringVector& argv);
  80 #endif
  81
  82   // Returns the represented command line string.
  83   // CAUTION! This should be avoided because quoting behavior is unclear.
  84   StringType command_line_string() const;
  85
  86 #if defined(OS_POSIX)
  87   // Returns the original command line string as a vector of strings.
  88   const StringVector& argv() const { return argv_; }
  89 #endif
  90
  91   // Returns the program part of the command line string (the first item).
  92   FilePath GetProgram() const;
  93
  94   // Returns true if this command line contains the given switch.
  95   // (Switch names are case-insensitive).
  96   bool HasSwitch(const std::string& switch_string) const;
  97
  98   // Returns the value associated with the given switch. If the switch has no
  99   // value or isn't present, this method returns the empty string.
 100   std::string GetSwitchValueASCII(const std::string& switch_string) const;
 101   FilePath GetSwitchValuePath(const std::string& switch_string) const;
 102   StringType GetSwitchValueNative(const std::string& switch_string) const;
 103
 104   // Get the number of switches in this process.
 105   // TODO(msw): Remove unnecessary API.
 106   size_t GetSwitchCount() const;
 107
 108   // Get a copy of all switches, along with their values.
 109   const SwitchMap& GetSwitches() const { return switches_; }
 110
 111   // Append a switch [with optional value] to the command line.
 112   // CAUTION! Appending a switch after the "--" switch terminator is futile!
 113   void AppendSwitch(const std::string& switch_string);
 114   void AppendSwitchPath(const std::string& switch_string, const FilePath& path);
 115   void AppendSwitchNative(const std::string& switch_string,
 116                           const StringType& value);
 117   void AppendSwitchASCII(const std::string& switch_string,
 118                          const std::string& value);
 119   void AppendSwitches(const CommandLine& other);
 120
 121   // Copy a set of switches (and any values) from another command line.
 122   // Commonly used when launching a subprocess.
 123   void CopySwitchesFrom(const CommandLine& source, const char* const switches[],
 124                         size_t count);
 125
 126   // Get the remaining arguments to the command.
 127   const StringVector& args() const { return args_; }
 128
 129   // Append an argument to the command line. Note that the argument is quoted
 130   // properly such that it is interpreted as one argument to the target command.
 131   // AppendArg is primarily for ASCII; non-ASCII input is interpreted as UTF-8.
 132   void AppendArg(const std::string& value);
 133   void AppendArgPath(const FilePath& value);
 134   void AppendArgNative(const StringType& value);
 135   void AppendArgs(const CommandLine& other);
 136
 137   // Append the arguments from another command line to this one.
 138   // If |include_program| is true, include |other|'s program as well.
 139   void AppendArguments(const CommandLine& other,
 140                        bool include_program);
 141
 142   // Insert a command before the current command.
 143   // Common for debuggers, like "valgrind" or "gdb --args".
 144   void PrependWrapper(const StringType& wrapper);
 145
 146 #if defined(OS_WIN)
 147   // Initialize by parsing the given command line string.
 148   // The program name is assumed to be the first item in the string.
 149   void ParseFromString(const std::wstring& command_line);
 150 #endif
 151
 152  private:
 153   // Disallow public default construction; a program name must be specified.
 154   CommandLine();
 155
 156   // The singleton CommandLine representing the current process's command line.
 157   static CommandLine* current_process_commandline_;
 158
 159   // We store a platform-native version of the command line, used when building
 160   // up a new command line to be executed. This ifdef delimits that code.
 161 #if defined(OS_WIN)
 162   // The quoted, space-separated command line string.
 163   StringType command_line_string_;
 164   // The name of the program.
 165   StringType program_;
 166 #elif defined(OS_POSIX)
 167   // The argv array, with the program name in argv_[0].
 168   StringVector argv_;
 169 #endif
 170
 171   // Parsed-out switch keys and values.
 172   SwitchMap switches_;
 173
 174   // Non-switch command line arguments.
 175   StringVector args_;
 176
 177   // Allow the copy constructor. A common pattern is to copy the current
 178   // process's command line and then add some flags to it. For example:
 179   //   CommandLine cl(*CommandLine::ForCurrentProcess());
 180   //   cl.AppendSwitch(...);
 181 };
 182
 183 #endif  // BASE_COMMAND_LINE_H_