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

 // Copyright 2012 The Chromium Authors
 // 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".
 // If a switch is specified multiple times, only the last value is used.
 // 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 <functional>
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>

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

 namespace base {

 class DuplicateSwitchHandler;
 class FilePath;

 class BASE_EXPORT CommandLine {
  public:
 #if BUILDFLAG(IS_WIN)
   // The native command line string type.
   using StringType = std::wstring;
 #elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
   using StringType = std::string;
 #endif

   using CharType = StringType::value_type;
   using StringPieceType = base::BasicStringPiece<CharType>;
   using StringVector = std::vector<StringType>;
   using SwitchMap = std::map<std::string, StringType, std::less<>>;

   // 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);

   CommandLine(const CommandLine& other);
   CommandLine& operator=(const CommandLine& other);

   ~CommandLine();

 #if BUILDFLAG(IS_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();

   // Normally when the CommandLine singleton is initialized it gets the command
   // line via the GetCommandLineW API and then uses the shell32 API
   // CommandLineToArgvW to parse the command line and convert it back to
   // argc and argv. Tests who don't want this dependency on shell32 and need
   // to honor the arguments passed in should use this function.
   static void InitUsingArgvForTesting(int argc, const char* const* argv);
 #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.
   // Do not call this in tests. Use base::test::ScopedCommandLine instead.
   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 BUILDFLAG(IS_WIN)
   static CommandLine FromString(StringPieceType 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.
   // CAUTION! If writing a command line to the Windows registry, use
   // GetCommandLineStringForShell() instead.
   StringType GetCommandLineString() const;

 #if BUILDFLAG(IS_WIN)
   // Quotes and escapes `arg` if necessary so that it will be interpreted as a
   // single command-line parameter according to the following rules in line with
   // `::CommandLineToArgvW` and C++ `main`:
   // * Returns `arg` unchanged if `arg` does not include any characters that may
   // need encoding, which is spaces, tabs, backslashes, and double-quotes.
   // * Otherwise, double-quotes `arg` and in addition:
   //   * Escapes any double-quotes in `arg` with backslashes.
   //   * Escapes backslashes in `arg` if:
   //     * `arg` ends with backslashes , or
   //     * the backslashes end in a pre-existing double quote.
   //
   // https://learn.microsoft.com/en-us/search/?terms=CommandLineToArgvW and
   // http://msdn.microsoft.com/en-us/library/17w5ykft.aspx#parsing-c-command-line-arguments.
   static std::wstring QuoteForCommandLineToArgvW(const std::wstring& arg);

   // Returns the command-line string in the proper format for the Windows shell,
   // ending with the argument placeholder "--single-argument %1". The single-
   // argument switch prevents unexpected parsing of arguments from other
   // software that cannot be trusted to escape double quotes when substituting
   // into a placeholder (e.g., "%1" insert sequences populated by the Windows
   // shell).
   // NOTE: this must be used to generate the command-line string for the shell
   // even if this command line was parsed from a string with the proper syntax,
   // because the --single-argument switch is not preserved during parsing.
   StringType GetCommandLineStringForShell() const;

   // Returns the represented command-line string. Allows the use of unsafe
   // Windows insert sequences like "%1". Only use this method if
   // GetCommandLineStringForShell() is not adequate AND the processor inserting
   // the arguments is known to do so securely (i.e., is not the Windows shell).
   // If in doubt, do not use.
   StringType GetCommandLineStringWithUnsafeInsertSequences() const;
 #endif

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

   // 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(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(StringPiece switch_string) const;
   FilePath GetSwitchValuePath(StringPiece switch_string) const;
   StringType GetSwitchValueNative(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(StringPiece switch_string);
   void AppendSwitchPath(StringPiece switch_string, const FilePath& path);
   void AppendSwitchNative(StringPiece switch_string, StringPieceType value);
   void AppendSwitchASCII(StringPiece switch_string, StringPiece value);

   // Removes the switch that matches |switch_key_without_prefix|, regardless of
   // prefix and value. If no such switch is present, this has no effect.
   void RemoveSwitch(const base::StringPiece switch_key_without_prefix);

   // 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(StringPiece value);
   void AppendArgPath(const FilePath& value);
   void AppendArgNative(StringPieceType 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 "gdb --args".
   void PrependWrapper(StringPieceType wrapper);

 #if BUILDFLAG(IS_WIN)
   // Initialize by parsing the given command line string.
   // The program name is assumed to be the first item in the string.
   void ParseFromString(StringPieceType command_line);

   // Returns true if the command line had the --single-argument switch, and
   // thus likely came from a Windows shell registration. This is only set if the
   // command line is parsed, and is not changed after it is parsed.
   bool HasSingleArgumentSwitch() const { return has_single_argument_switch_; }
 #endif

   // Sets a delegate that's called when we encounter a duplicate switch
   static void SetDuplicateSwitchHandler(
       std::unique_ptr<DuplicateSwitchHandler>);

  private:
   // Disallow default constructor; a program name must be explicitly specified.
   CommandLine() = delete;
   // 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(...);

   // Append switches and arguments, keeping switches before arguments.
   void AppendSwitchesAndArguments(const StringVector& argv);

   // Internal version of GetArgumentsString to support allowing unsafe insert
   // sequences in rare cases (see
   // GetCommandLineStringWithUnsafeInsertSequences).
   StringType GetArgumentsStringInternal(
       bool allow_unsafe_insert_sequences) const;

 #if BUILDFLAG(IS_WIN)
   // Initializes by parsing |raw_command_line_string_|, treating everything
   // after |single_arg_switch_string| + <a single character> as the command
   // line's single argument, and dropping any arguments previously parsed. The
   // command line must contain |single_arg_switch_string|, and the argument, if
   // present, must be separated from |single_arg_switch_string| by one
   // character.
   // NOTE: the single-argument switch is not preserved after parsing;
   // GetCommandLineStringForShell() must be used to reproduce the original
   // command-line string with single-argument switch.
   void ParseAsSingleArgument(const StringType& single_arg_switch_string);

   // The string returned by GetCommandLineW(), to be parsed via
   // ParseFromString(). Empty if this command line was not parsed from a string,
   // or if ParseFromString() has finished executing.
   StringPieceType raw_command_line_string_;

   // Set to true if the command line had --single-argument when initially
   // parsed. It does not change if the command line mutates after initial
   // parsing.
   bool has_single_argument_switch_ = false;
 #endif

   // 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_;

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

 class BASE_EXPORT DuplicateSwitchHandler {
  public:
   // out_value contains the existing value of the switch
   virtual void ResolveDuplicate(base::StringPiece key,
                                 CommandLine::StringPieceType new_value,
                                 CommandLine::StringType& out_value) = 0;
   virtual ~DuplicateSwitchHandler() = default;
 };

 }  // namespace base

 #endif  // BASE_COMMAND_LINE_H_
	// Copyright 2012 The Chromium Authors
	// 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".
	// If a switch is specified multiple times, only the last value is used.
	// 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 <functional>
	#include <map>
	#include <memory>
	#include <string>
	#include <vector>

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

	namespace base {

	class DuplicateSwitchHandler;
	class FilePath;

	class BASE_EXPORT CommandLine {
	public:
	#if BUILDFLAG(IS_WIN)
	// The native command line string type.
	using StringType = std::wstring;
	#elif BUILDFLAG(IS_POSIX) \|\| BUILDFLAG(IS_FUCHSIA)
	using StringType = std::string;
	#endif

	using CharType = StringType::value_type;
	using StringPieceType = base::BasicStringPiece<CharType>;
	using StringVector = std::vector<StringType>;
	using SwitchMap = std::map<std::string, StringType, std::less<>>;

	// 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);

	CommandLine(const CommandLine& other);
	CommandLine& operator=(const CommandLine& other);

	~CommandLine();

	#if BUILDFLAG(IS_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();

	// Normally when the CommandLine singleton is initialized it gets the command
	// line via the GetCommandLineW API and then uses the shell32 API
	// CommandLineToArgvW to parse the command line and convert it back to
	// argc and argv. Tests who don't want this dependency on shell32 and need
	// to honor the arguments passed in should use this function.
	static void InitUsingArgvForTesting(int argc, const char* const* argv);
	#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.
	// Do not call this in tests. Use base::test::ScopedCommandLine instead.
	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 BUILDFLAG(IS_WIN)
	static CommandLine FromString(StringPieceType 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.
	// CAUTION! If writing a command line to the Windows registry, use
	// GetCommandLineStringForShell() instead.
	StringType GetCommandLineString() const;

	#if BUILDFLAG(IS_WIN)
	// Quotes and escapes `arg` if necessary so that it will be interpreted as a
	// single command-line parameter according to the following rules in line with
	// `::CommandLineToArgvW` and C++ `main`:
	// * Returns `arg` unchanged if `arg` does not include any characters that may
	// need encoding, which is spaces, tabs, backslashes, and double-quotes.
	// * Otherwise, double-quotes `arg` and in addition:
	// * Escapes any double-quotes in `arg` with backslashes.
	// * Escapes backslashes in `arg` if:
	// * `arg` ends with backslashes , or
	// * the backslashes end in a pre-existing double quote.
	//
	// https://learn.microsoft.com/en-us/search/?terms=CommandLineToArgvW and
	// http://msdn.microsoft.com/en-us/library/17w5ykft.aspx#parsing-c-command-line-arguments.
	static std::wstring QuoteForCommandLineToArgvW(const std::wstring& arg);

	// Returns the command-line string in the proper format for the Windows shell,
	// ending with the argument placeholder "--single-argument %1". The single-
	// argument switch prevents unexpected parsing of arguments from other
	// software that cannot be trusted to escape double quotes when substituting
	// into a placeholder (e.g., "%1" insert sequences populated by the Windows
	// shell).
	// NOTE: this must be used to generate the command-line string for the shell
	// even if this command line was parsed from a string with the proper syntax,
	// because the --single-argument switch is not preserved during parsing.
	StringType GetCommandLineStringForShell() const;

	// Returns the represented command-line string. Allows the use of unsafe
	// Windows insert sequences like "%1". Only use this method if
	// GetCommandLineStringForShell() is not adequate AND the processor inserting
	// the arguments is known to do so securely (i.e., is not the Windows shell).
	// If in doubt, do not use.
	StringType GetCommandLineStringWithUnsafeInsertSequences() const;
	#endif

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

	// 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(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(StringPiece switch_string) const;
	FilePath GetSwitchValuePath(StringPiece switch_string) const;
	StringType GetSwitchValueNative(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(StringPiece switch_string);
	void AppendSwitchPath(StringPiece switch_string, const FilePath& path);
	void AppendSwitchNative(StringPiece switch_string, StringPieceType value);
	void AppendSwitchASCII(StringPiece switch_string, StringPiece value);

	// Removes the switch that matches \|switch_key_without_prefix\|, regardless of
	// prefix and value. If no such switch is present, this has no effect.
	void RemoveSwitch(const base::StringPiece switch_key_without_prefix);

	// 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(StringPiece value);
	void AppendArgPath(const FilePath& value);
	void AppendArgNative(StringPieceType 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 "gdb --args".
	void PrependWrapper(StringPieceType wrapper);

	#if BUILDFLAG(IS_WIN)
	// Initialize by parsing the given command line string.
	// The program name is assumed to be the first item in the string.
	void ParseFromString(StringPieceType command_line);

	// Returns true if the command line had the --single-argument switch, and
	// thus likely came from a Windows shell registration. This is only set if the
	// command line is parsed, and is not changed after it is parsed.
	bool HasSingleArgumentSwitch() const { return has_single_argument_switch_; }
	#endif

	// Sets a delegate that's called when we encounter a duplicate switch
	static void SetDuplicateSwitchHandler(
	std::unique_ptr<DuplicateSwitchHandler>);

	private:
	// Disallow default constructor; a program name must be explicitly specified.
	CommandLine() = delete;
	// 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(...);

	// Append switches and arguments, keeping switches before arguments.
	void AppendSwitchesAndArguments(const StringVector& argv);

	// Internal version of GetArgumentsString to support allowing unsafe insert
	// sequences in rare cases (see
	// GetCommandLineStringWithUnsafeInsertSequences).
	StringType GetArgumentsStringInternal(
	bool allow_unsafe_insert_sequences) const;

	#if BUILDFLAG(IS_WIN)
	// Initializes by parsing \|raw_command_line_string_\|, treating everything
	// after \|single_arg_switch_string\| + <a single character> as the command
	// line's single argument, and dropping any arguments previously parsed. The
	// command line must contain \|single_arg_switch_string\|, and the argument, if
	// present, must be separated from \|single_arg_switch_string\| by one
	// character.
	// NOTE: the single-argument switch is not preserved after parsing;
	// GetCommandLineStringForShell() must be used to reproduce the original
	// command-line string with single-argument switch.
	void ParseAsSingleArgument(const StringType& single_arg_switch_string);

	// The string returned by GetCommandLineW(), to be parsed via
	// ParseFromString(). Empty if this command line was not parsed from a string,
	// or if ParseFromString() has finished executing.
	StringPieceType raw_command_line_string_;

	// Set to true if the command line had --single-argument when initially
	// parsed. It does not change if the command line mutates after initial
	// parsing.
	bool has_single_argument_switch_ = false;
	#endif

	// 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_;

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

	class BASE_EXPORT DuplicateSwitchHandler {
	public:
	// out_value contains the existing value of the switch
	virtual void ResolveDuplicate(base::StringPiece key,
	CommandLine::StringPieceType new_value,
	CommandLine::StringType& out_value) = 0;
	virtual ~DuplicateSwitchHandler() = default;
	};

	} // namespace base

	#endif // BASE_COMMAND_LINE_H_