base/command_line.h

   1 // Copyright (c) 2012 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 // Arguments with prefixes ('--', '-', and on Windows, '/') are switches.
   7 // Switches will precede all other arguments without switch prefixes.
   8 // Switches can optionally have values, delimited by '=', e.g., "-switch=value".
   9 // An argument of "--" will terminate switch parsing during initialization,
  10 // interpreting subsequent tokens as non-switch arguments, regardless of prefix.
  11
  12 // There is a singleton read-only CommandLine that represents the command line
  13 // that the current process was started with.  It must be initialized in main().
  14
  15 #ifndef BASE_COMMAND_LINE_H_
  16 #define BASE_COMMAND_LINE_H_
  17
  18 #include <stddef.h>
  19 #include <map>
  20 #include <string>
  21 #include <vector>
  22
  23 #include "base/base_export.h"
  24 #include "build/build_config.h"
  25
  26 namespace base {
  27 class FilePath;
  28 }
  29
  30 class BASE_EXPORT CommandLine {
  31  public:
  32 #if defined(OS_WIN)
  33   // The native command line string type.
  34   typedef std::wstring StringType;
  35 #elif defined(OS_POSIX)
  36   typedef std::string StringType;
  37 #endif
  38
  39   typedef StringType::value_type CharType;
  40   typedef std::vector<StringType> StringVector;
  41   typedef std::map<std::string, StringType> SwitchMap;
  42
  43   // A constructor for CommandLines that only carry switches and arguments.
  44   enum NoProgram { NO_PROGRAM };
  45   explicit CommandLine(NoProgram no_program);
  46
  47   // Construct a new command line with |program| as argv[0].
  48   explicit CommandLine(const base::FilePath& program);
  49
  50   // Construct a new command line from an argument list.
  51   CommandLine(int argc, const CharType* const* argv);
  52   explicit CommandLine(const StringVector& argv);
  53
  54   ~CommandLine();
  55
  56   // Initialize the current process CommandLine singleton. On Windows, ignores
  57   // its arguments (we instead parse GetCommandLineW() directly) because we
  58   // don't trust the CRT's parsing of the command line, but it still must be
  59   // called to set up the command line. Returns false if initialization has
  60   // already occurred, and true otherwise. Only the caller receiving a 'true'
  61   // return value should take responsibility for calling Reset.
  62   static bool Init(int argc, const char* const* argv);
  63
  64   // Destroys the current process CommandLine singleton. This is necessary if
  65   // you want to reset the base library to its initial state (for example, in an
  66   // outer library that needs to be able to terminate, and be re-initialized).
  67   // If Init is called only once, as in main(), Reset() is not necessary.
  68   static void Reset();
  69
  70   // Get the singleton CommandLine representing the current process's
  71   // command line. Note: returned value is mutable, but not thread safe;
  72   // only mutate if you know what you're doing!
  73   static CommandLine* ForCurrentProcess();
  74
  75 #if defined(OS_WIN)
  76   static CommandLine FromString(const std::wstring& command_line);
  77 #endif
  78
  79   // Initialize from an argv vector.
  80   void InitFromArgv(int argc, const CharType* const* argv);
  81   void InitFromArgv(const StringVector& argv);
  82
  83   // Constructs and returns the represented command line string.
  84   // CAUTION! This should be avoided on POSIX because quoting behavior is
  85   // unclear.
  86   StringType GetCommandLineString() const;
  87
  88   // Constructs and returns the represented arguments string.
  89   // CAUTION! This should be avoided on POSIX because quoting behavior is
  90   // unclear.
  91   StringType GetArgumentsString() const;
  92
  93   // Returns the original command line string as a vector of strings.
  94   const StringVector& argv() const { return argv_; }
  95
  96   // Get and Set the program part of the command line string (the first item).
  97   base::FilePath GetProgram() const;
  98   void SetProgram(const base::FilePath& program);
  99
 100   // Returns true if this command line contains the given switch.
 101   // (Switch names are case-insensitive).
 102   bool HasSwitch(const std::string& switch_string) const;
 103
 104   // Returns the value associated with the given switch. If the switch has no
 105   // value or isn't present, this method returns the empty string.
 106   std::string GetSwitchValueASCII(const std::string& switch_string) const;
 107   base::FilePath GetSwitchValuePath(const std::string& switch_string) const;
 108   StringType GetSwitchValueNative(const std::string& switch_string) const;
 109
 110   // Get a copy of all switches, along with their values.
 111   const SwitchMap& GetSwitches() const { return switches_; }
 112
 113   // Append a switch [with optional value] to the command line.
 114   // Note: Switches will precede arguments regardless of appending order.
 115   void AppendSwitch(const std::string& switch_string);
 116   void AppendSwitchPath(const std::string& switch_string,
 117                         const base::FilePath& path);
 118   void AppendSwitchNative(const std::string& switch_string,
 119                           const StringType& value);
 120   void AppendSwitchASCII(const std::string& switch_string,
 121                          const std::string& value);
 122
 123   // Copy a set of switches (and any values) from another command line.
 124   // Commonly used when launching a subprocess.
 125   void CopySwitchesFrom(const CommandLine& source,
 126                         const char* const switches[],
 127                         size_t count);
 128
 129   // Get the remaining arguments to the command.
 130   StringVector GetArgs() const;
 131
 132   // Append an argument to the command line. Note that the argument is quoted
 133   // properly such that it is interpreted as one argument to the target command.
 134   // AppendArg is primarily for ASCII; non-ASCII input is interpreted as UTF-8.
 135   // Note: Switches will precede arguments regardless of appending order.
 136   void AppendArg(const std::string& value);
 137   void AppendArgPath(const base::FilePath& value);
 138   void AppendArgNative(const StringType& value);
 139
 140   // Append the switches and arguments from another command line to this one.
 141   // If |include_program| is true, include |other|'s program as well.
 142   void AppendArguments(const CommandLine& other, bool include_program);
 143
 144   // Insert a command before the current command.
 145   // Common for debuggers, like "valgrind" or "gdb --args".
 146   void PrependWrapper(const StringType& wrapper);
 147
 148 #if defined(OS_WIN)
 149   // Initialize by parsing the given command line string.
 150   // The program name is assumed to be the first item in the string.
 151   void ParseFromString(const std::wstring& command_line);
 152 #endif
 153
 154  private:
 155   // Disallow default constructor; a program name must be explicitly specified.
 156   CommandLine();
 157   // Allow the copy constructor. A common pattern is to copy of the current
 158   // process's command line and then add some flags to it. For example:
 159   //   CommandLine cl(*CommandLine::ForCurrentProcess());
 160   //   cl.AppendSwitch(...);
 161
 162   // The singleton CommandLine representing the current process's command line.
 163   static CommandLine* current_process_commandline_;
 164
 165   // The argv array: { program, [(--|-|/)switch[=value]]*, [--], [argument]* }
 166   StringVector argv_;
 167
 168   // Parsed-out switch keys and values.
 169   SwitchMap switches_;
 170
 171   // The index after the program and switches, any arguments start here.
 172   size_t begin_args_;
 173 };
 174
 175 #endif  // BASE_COMMAND_LINE_H_