base/command_line.h - chromium/src - Git at Google

 // 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.

 // This class works with command lines: building and parsing.
 // Arguments with prefixes ('--', '-', and on Windows, '/') are switches.
 // Switches will precede all other arguments without switch prefixes.
 // Switches can optionally have values, delimited by '=', e.g., "-switch=value".
 // An argument of "--" will terminate switch parsing during initialization,
 // interpreting subsequent tokens as non-switch arguments, regardless of prefix.

 // There is a singleton read-only CommandLine that represents the command line
 // that the current process was started with.  It must be initialized in main().

 #ifndef BASE_COMMAND_LINE_H_
 #define BASE_COMMAND_LINE_H_

 #include <stddef.h>
 #include <map>
 #include <string>
 #include <vector>

 #include "base/base_export.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_piece.h"
 #include "build/build_config.h"

 namespace base {

 class FilePath;

 class BASE_EXPORT CommandLine {
  public:
 #if defined(OS_WIN)
   // The native command line string type.
   typedef base::string16 StringType;
 #elif defined(OS_POSIX)
   typedef std::string StringType;
 #endif

   typedef StringType::value_type CharType;
   typedef std::vector<StringType> StringVector;
   typedef std::map<std::string, StringType> SwitchMap;
   typedef std::map<base::StringPiece, const StringType*> StringPieceSwitchMap;

   // A constructor for CommandLines that only carry switches and arguments.
   enum NoProgram { NO_PROGRAM };
   explicit CommandLine(NoProgram no_program);

   // Construct a new command line with |program| as argv[0].
   explicit CommandLine(const FilePath& program);

   // Construct a new command line from an argument list.
   CommandLine(int argc, const CharType* const* argv);
   explicit CommandLine(const StringVector& argv);

   // Override copy and assign to ensure |switches_by_stringpiece_| is valid.
   CommandLine(const CommandLine& other);
   CommandLine& operator=(const CommandLine& other);

   ~CommandLine();

 #if defined(OS_WIN)
   // By default this class will treat command-line arguments beginning with
   // slashes as switches on Windows, but not other platforms.
   //
   // If this behavior is inappropriate for your application, you can call this
   // function BEFORE initializing the current process' global command line
   // object and the behavior will be the same as Posix systems (only hyphens
   // begin switches, everything else will be an arg).
   static void set_slash_is_not_a_switch();
 #endif

   // Initialize the current process CommandLine singleton. On Windows, ignores
   // its arguments (we instead parse GetCommandLineW() directly) because we
   // don't trust the CRT's parsing of the command line, but it still must be
   // called to set up the command line. Returns false if initialization has
   // already occurred, and true otherwise. Only the caller receiving a 'true'
   // return value should take responsibility for calling Reset.
   static bool Init(int argc, const char* const* argv);

   // Destroys the current process CommandLine singleton. This is necessary if
   // you want to reset the base library to its initial state (for example, in an
   // outer library that needs to be able to terminate, and be re-initialized).
   // If Init is called only once, as in main(), Reset() is not necessary.
   static void Reset();

   // Get the singleton CommandLine representing the current process's
   // command line. Note: returned value is mutable, but not thread safe;
   // only mutate if you know what you're doing!
   static CommandLine* ForCurrentProcess();

   // Returns true if the CommandLine has been initialized for the given process.
   static bool InitializedForCurrentProcess();

 #if defined(OS_WIN)
   static CommandLine FromString(const base::string16& command_line);
 #endif

   // Initialize from an argv vector.
   void InitFromArgv(int argc, const CharType* const* argv);
   void InitFromArgv(const StringVector& argv);

   // Constructs and returns the represented command line string.
   // CAUTION! This should be avoided on POSIX because quoting behavior is
   // unclear.
   StringType GetCommandLineString() const {
     return GetCommandLineStringInternal(false);
   }

 #if defined(OS_WIN)
   // Constructs and returns the represented command line string. Assumes the
   // command line contains placeholders (eg, %1) and quotes any program or
   // argument with a '%' in it. This should be avoided unless the placeholder is
   // required by an external interface (eg, the Windows registry), because it is
   // not generally safe to replace it with an arbitrary string. If possible,
   // placeholders should be replaced *before* converting the command line to a
   // string.
   StringType GetCommandLineStringWithPlaceholders() const {
     return GetCommandLineStringInternal(true);
   }
 #endif

   // Constructs and returns the represented arguments string.
   // CAUTION! This should be avoided on POSIX because quoting behavior is
   // unclear.
   StringType GetArgumentsString() const {
     return GetArgumentsStringInternal(false);
   }

 #if defined(OS_WIN)
   // Constructs and returns the represented arguments string. Assumes the
   // command line contains placeholders (eg, %1) and quotes any argument with a
   // '%' in it. This should be avoided unless the placeholder is required by an
   // external interface (eg, the Windows registry), because it is not generally
   // safe to replace it with an arbitrary string. If possible, placeholders
   // should be replaced *before* converting the arguments to a string.
   StringType GetArgumentsStringWithPlaceholders() const {
     return GetArgumentsStringInternal(true);
   }
 #endif

   // Returns the original command line string as a vector of strings.
   const StringVector& argv() const { return argv_; }

   // Get and Set the program part of the command line string (the first item).
   FilePath GetProgram() const;
   void SetProgram(const FilePath& program);

   // Returns true if this command line contains the given switch.
   // Switch names must be lowercase.
   // The second override provides an optimized version to avoid inlining codegen
   // at every callsite to find the length of the constant and construct a
   // StringPiece.
   bool HasSwitch(const base::StringPiece& switch_string) const;
   bool HasSwitch(const char switch_constant[]) 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.
   // Switch names must be lowercase.
   std::string GetSwitchValueASCII(const base::StringPiece& switch_string) const;
   FilePath GetSwitchValuePath(const base::StringPiece& switch_string) const;
   StringType GetSwitchValueNative(const base::StringPiece& switch_string) const;

   // Get a copy of all switches, along with their values.
   const SwitchMap& GetSwitches() const { return switches_; }

   // Append a switch [with optional value] to the command line.
   // Note: Switches will precede arguments regardless of appending order.
   void AppendSwitch(const std::string& switch_string);
   void AppendSwitchPath(const std::string& switch_string,
                         const FilePath& path);
   void AppendSwitchNative(const std::string& switch_string,
                           const StringType& value);
   void AppendSwitchASCII(const std::string& switch_string,
                          const std::string& value);

   // Copy a set of switches (and any values) from another command line.
   // Commonly used when launching a subprocess.
   void CopySwitchesFrom(const CommandLine& source,
                         const char* const switches[],
                         size_t count);

   // Get the remaining arguments to the command.
   StringVector GetArgs() const;

   // Append an argument to the command line. Note that the argument is quoted
   // properly such that it is interpreted as one argument to the target command.
   // AppendArg is primarily for ASCII; non-ASCII input is interpreted as UTF-8.
   // Note: Switches will precede arguments regardless of appending order.
   void AppendArg(const std::string& value);
   void AppendArgPath(const FilePath& value);
   void AppendArgNative(const StringType& value);

   // Append the switches and arguments from another command line to this one.
   // If |include_program| is true, include |other|'s program as well.
   void AppendArguments(const CommandLine& other, bool include_program);

   // Insert a command before the current command.
   // Common for debuggers, like "valgrind" or "gdb --args".
   void PrependWrapper(const StringType& wrapper);

 #if defined(OS_WIN)
   // Initialize by parsing the given command line string.
   // The program name is assumed to be the first item in the string.
   void ParseFromString(const base::string16& command_line);
 #endif

  private:
   // Disallow default constructor; a program name must be explicitly specified.
   CommandLine();
   // Allow the copy constructor. A common pattern is to copy of the current
   // process's command line and then add some flags to it. For example:
   //   CommandLine cl(*CommandLine::ForCurrentProcess());
   //   cl.AppendSwitch(...);

   // Internal version of GetCommandLineString. If |quote_placeholders| is true,
   // also quotes parts with '%' in them.
   StringType GetCommandLineStringInternal(bool quote_placeholders) const;

   // Internal version of GetArgumentsString. If |quote_placeholders| is true,
   // also quotes parts with '%' in them.
   StringType GetArgumentsStringInternal(bool quote_placeholders) const;

   // Reconstruct |switches_by_stringpiece| to be a mirror of |switches|.
   // |switches_by_stringpiece| only contains pointers to objects owned by
   // |switches|.
   void ResetStringPieces();

   // The singleton CommandLine representing the current process's command line.
   static CommandLine* current_process_commandline_;

   // The argv array: { program, [(--|-|/)switch[=value]]*, [--], [argument]* }
   StringVector argv_;

   // Parsed-out switch keys and values.
   SwitchMap switches_;

   // A mirror of |switches_| with only references to the actual strings.
   // The StringPiece internally holds a pointer to a key in |switches_| while
   // the mapped_type points to a value in |switches_|.
   // Used for allocation-free lookups.
   StringPieceSwitchMap switches_by_stringpiece_;

   // The index after the program and switches, any arguments start here.
   size_t begin_args_;
 };

 }  // namespace base

 #endif  // BASE_COMMAND_LINE_H_
	// 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.

	// This class works with command lines: building and parsing.
	// Arguments with prefixes ('--', '-', and on Windows, '/') are switches.
	// Switches will precede all other arguments without switch prefixes.
	// Switches can optionally have values, delimited by '=', e.g., "-switch=value".
	// An argument of "--" will terminate switch parsing during initialization,
	// interpreting subsequent tokens as non-switch arguments, regardless of prefix.

	// There is a singleton read-only CommandLine that represents the command line
	// that the current process was started with. It must be initialized in main().

	#ifndef BASE_COMMAND_LINE_H_
	#define BASE_COMMAND_LINE_H_

	#include <stddef.h>
	#include <map>
	#include <string>
	#include <vector>

	#include "base/base_export.h"
	#include "base/strings/string16.h"
	#include "base/strings/string_piece.h"
	#include "build/build_config.h"

	namespace base {

	class FilePath;

	class BASE_EXPORT CommandLine {
	public:
	#if defined(OS_WIN)
	// The native command line string type.
	typedef base::string16 StringType;
	#elif defined(OS_POSIX)
	typedef std::string StringType;
	#endif

	typedef StringType::value_type CharType;
	typedef std::vector<StringType> StringVector;
	typedef std::map<std::string, StringType> SwitchMap;
	typedef std::map<base::StringPiece, const StringType*> StringPieceSwitchMap;

	// A constructor for CommandLines that only carry switches and arguments.
	enum NoProgram { NO_PROGRAM };
	explicit CommandLine(NoProgram no_program);

	// Construct a new command line with \|program\| as argv[0].
	explicit CommandLine(const FilePath& program);

	// Construct a new command line from an argument list.
	CommandLine(int argc, const CharType* const* argv);
	explicit CommandLine(const StringVector& argv);

	// Override copy and assign to ensure \|switches_by_stringpiece_\| is valid.
	CommandLine(const CommandLine& other);
	CommandLine& operator=(const CommandLine& other);

	~CommandLine();

	#if defined(OS_WIN)
	// By default this class will treat command-line arguments beginning with
	// slashes as switches on Windows, but not other platforms.
	//
	// If this behavior is inappropriate for your application, you can call this
	// function BEFORE initializing the current process' global command line
	// object and the behavior will be the same as Posix systems (only hyphens
	// begin switches, everything else will be an arg).
	static void set_slash_is_not_a_switch();
	#endif

	// Initialize the current process CommandLine singleton. On Windows, ignores
	// its arguments (we instead parse GetCommandLineW() directly) because we
	// don't trust the CRT's parsing of the command line, but it still must be
	// called to set up the command line. Returns false if initialization has
	// already occurred, and true otherwise. Only the caller receiving a 'true'
	// return value should take responsibility for calling Reset.
	static bool Init(int argc, const char* const* argv);

	// Destroys the current process CommandLine singleton. This is necessary if
	// you want to reset the base library to its initial state (for example, in an
	// outer library that needs to be able to terminate, and be re-initialized).
	// If Init is called only once, as in main(), Reset() is not necessary.
	static void Reset();

	// Get the singleton CommandLine representing the current process's
	// command line. Note: returned value is mutable, but not thread safe;
	// only mutate if you know what you're doing!
	static CommandLine* ForCurrentProcess();

	// Returns true if the CommandLine has been initialized for the given process.
	static bool InitializedForCurrentProcess();

	#if defined(OS_WIN)
	static CommandLine FromString(const base::string16& command_line);
	#endif

	// Initialize from an argv vector.
	void InitFromArgv(int argc, const CharType* const* argv);
	void InitFromArgv(const StringVector& argv);

	// Constructs and returns the represented command line string.
	// CAUTION! This should be avoided on POSIX because quoting behavior is
	// unclear.
	StringType GetCommandLineString() const {
	return GetCommandLineStringInternal(false);
	}

	#if defined(OS_WIN)
	// Constructs and returns the represented command line string. Assumes the
	// command line contains placeholders (eg, %1) and quotes any program or
	// argument with a '%' in it. This should be avoided unless the placeholder is
	// required by an external interface (eg, the Windows registry), because it is
	// not generally safe to replace it with an arbitrary string. If possible,
	// placeholders should be replaced before converting the command line to a
	// string.
	StringType GetCommandLineStringWithPlaceholders() const {
	return GetCommandLineStringInternal(true);
	}
	#endif

	// Constructs and returns the represented arguments string.
	// CAUTION! This should be avoided on POSIX because quoting behavior is
	// unclear.
	StringType GetArgumentsString() const {
	return GetArgumentsStringInternal(false);
	}

	#if defined(OS_WIN)
	// Constructs and returns the represented arguments string. Assumes the
	// command line contains placeholders (eg, %1) and quotes any argument with a
	// '%' in it. This should be avoided unless the placeholder is required by an
	// external interface (eg, the Windows registry), because it is not generally
	// safe to replace it with an arbitrary string. If possible, placeholders
	// should be replaced before converting the arguments to a string.
	StringType GetArgumentsStringWithPlaceholders() const {
	return GetArgumentsStringInternal(true);
	}
	#endif

	// Returns the original command line string as a vector of strings.
	const StringVector& argv() const { return argv_; }

	// Get and Set the program part of the command line string (the first item).
	FilePath GetProgram() const;
	void SetProgram(const FilePath& program);

	// Returns true if this command line contains the given switch.
	// Switch names must be lowercase.
	// The second override provides an optimized version to avoid inlining codegen
	// at every callsite to find the length of the constant and construct a
	// StringPiece.
	bool HasSwitch(const base::StringPiece& switch_string) const;
	bool HasSwitch(const char switch_constant[]) 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.
	// Switch names must be lowercase.
	std::string GetSwitchValueASCII(const base::StringPiece& switch_string) const;
	FilePath GetSwitchValuePath(const base::StringPiece& switch_string) const;
	StringType GetSwitchValueNative(const base::StringPiece& switch_string) const;

	// Get a copy of all switches, along with their values.
	const SwitchMap& GetSwitches() const { return switches_; }

	// Append a switch [with optional value] to the command line.
	// Note: Switches will precede arguments regardless of appending order.
	void AppendSwitch(const std::string& switch_string);
	void AppendSwitchPath(const std::string& switch_string,
	const FilePath& path);
	void AppendSwitchNative(const std::string& switch_string,
	const StringType& value);
	void AppendSwitchASCII(const std::string& switch_string,
	const std::string& value);

	// Copy a set of switches (and any values) from another command line.
	// Commonly used when launching a subprocess.
	void CopySwitchesFrom(const CommandLine& source,
	const char* const switches[],
	size_t count);

	// Get the remaining arguments to the command.
	StringVector GetArgs() const;

	// Append an argument to the command line. Note that the argument is quoted
	// properly such that it is interpreted as one argument to the target command.
	// AppendArg is primarily for ASCII; non-ASCII input is interpreted as UTF-8.
	// Note: Switches will precede arguments regardless of appending order.
	void AppendArg(const std::string& value);
	void AppendArgPath(const FilePath& value);
	void AppendArgNative(const StringType& value);

	// Append the switches and arguments from another command line to this one.
	// If \|include_program\| is true, include \|other\|'s program as well.
	void AppendArguments(const CommandLine& other, bool include_program);

	// Insert a command before the current command.
	// Common for debuggers, like "valgrind" or "gdb --args".
	void PrependWrapper(const StringType& wrapper);

	#if defined(OS_WIN)
	// Initialize by parsing the given command line string.
	// The program name is assumed to be the first item in the string.
	void ParseFromString(const base::string16& command_line);
	#endif

	private:
	// Disallow default constructor; a program name must be explicitly specified.
	CommandLine();
	// Allow the copy constructor. A common pattern is to copy of the current
	// process's command line and then add some flags to it. For example:
	// CommandLine cl(*CommandLine::ForCurrentProcess());
	// cl.AppendSwitch(...);

	// Internal version of GetCommandLineString. If \|quote_placeholders\| is true,
	// also quotes parts with '%' in them.
	StringType GetCommandLineStringInternal(bool quote_placeholders) const;

	// Internal version of GetArgumentsString. If \|quote_placeholders\| is true,
	// also quotes parts with '%' in them.
	StringType GetArgumentsStringInternal(bool quote_placeholders) const;

	// Reconstruct \|switches_by_stringpiece\| to be a mirror of \|switches\|.
	// \|switches_by_stringpiece\| only contains pointers to objects owned by
	// \|switches\|.
	void ResetStringPieces();

	// The singleton CommandLine representing the current process's command line.
	static CommandLine* current_process_commandline_;

	// The argv array: { program, [(--\|-\|/)switch[=value]], [--], [argument] }
	StringVector argv_;

	// Parsed-out switch keys and values.
	SwitchMap switches_;

	// A mirror of \|switches_\| with only references to the actual strings.
	// The StringPiece internally holds a pointer to a key in \|switches_\| while
	// the mapped_type points to a value in \|switches_\|.
	// Used for allocation-free lookups.
	StringPieceSwitchMap switches_by_stringpiece_;

	// The index after the program and switches, any arguments start here.
	size_t begin_args_;
	};

	} // namespace base

	#endif // BASE_COMMAND_LINE_H_