thodg/libgit2/src/cli/cmd_help.c

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• Hash : f8e7d8fd
  Author :
  Date : 2021-11-26T17:33:38
  

  cli: support `help <command>` Support `help <command>` by re-invoking the command itself with the `--help` argument. This allows us to keep the help logic with the commands itself.

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• src/cli/cmd_help.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include <stdio.h>
  #include <git2.h>
  #include "cli.h"
  #include "cmd.h"
  
  #define COMMAND_NAME "help"
  
  static char *command;
  static int show_help;
  
  static const cli_opt_spec opts[] = {
  	{ CLI_OPT_TYPE_SWITCH,   "help",     0, &show_help, 1,
  	  CLI_OPT_USAGE_HIDDEN,   NULL,     "display help about the help command" },
  	{ CLI_OPT_TYPE_ARG,      "command",  0, &command,   0,
  	  CLI_OPT_USAGE_DEFAULT, "command", "the command to show help for" },
  	{ 0 },
  };
  
  static int print_help(void)
  {
  	cli_opt_usage_fprint(stdout, PROGRAM_NAME, COMMAND_NAME, opts);
  	printf("\n");
  
  	printf("Display help information about %s.  If a command is specified, help\n", PROGRAM_NAME);
  	printf("about that command will be shown.  Otherwise, general information about\n");
  	printf("%s will be shown, including the commands available.\n", PROGRAM_NAME);
  
  	return 0;
  }
  
  static int print_commands(void)
  {
  	const cli_cmd_spec *cmd;
  
  	cli_opt_usage_fprint(stdout, PROGRAM_NAME, NULL, cli_common_opts);
  	printf("\n");
  
  	printf("These are the %s commands available:\n\n", PROGRAM_NAME);
  
  	for (cmd = cli_cmds; cmd->name; cmd++)
  		printf("   %-11s  %s\n", cmd->name, cmd->desc);
  
  	printf("\nSee '%s help <command>' for more information on a specific command.\n", PROGRAM_NAME);
  
  	return 0;
  }
  
  int cmd_help(int argc, char **argv)
  {
  	char *fake_args[2];
  	const cli_cmd_spec *cmd;
  	cli_opt invalid_opt;
  
  	if (cli_opt_parse(&invalid_opt, opts, argv + 1, argc - 1, CLI_OPT_PARSE_GNU))
  		return cli_opt_usage_error(COMMAND_NAME, opts, &invalid_opt);
  
  	/* Show the meta-help */
  	if (show_help)
  		return print_help();
  
  	/* We were not asked to show help for a specific command. */
  	if (!command)
  		return print_commands();
  
  	/*
  	 * If we were asked for help for a command (eg, `help <command>`),
  	 * delegate back to that command's `--help` option.  This lets
  	 * commands own their help.  Emulate the command-line arguments
  	 * that would invoke `<command> --help` and invoke that command.
  	 */
  	fake_args[0] = command;
  	fake_args[1] = "--help";
  
  	if ((cmd = cli_cmd_spec_byname(command)) == NULL)
  		return cli_error("'%s' is not a %s command. See '%s help'.",
  		                command, PROGRAM_NAME, PROGRAM_NAME);
  
  	return cmd->fn(2, fake_args);
  }
  

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