transmission/libtransmission/tr-getopt.cc

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// This file Copyright © 2008-2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0), GPLv3 (SPDX: GPL-3.0),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <algorithm>
#include <cstdlib> /* exit() */
#include <cstring>
#include <string_view>
#include "transmission.h"
#include "tr-getopt.h"
#include "tr-macros.h"
#include "utils.h"
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int tr_optind = 1;
static char const* getArgName(tr_option const* opt)
{
if (!opt->has_arg)
{
return "";
}
if (opt->argName != nullptr)
{
return opt->argName;
}
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return "<args>";
}
static size_t get_next_line_len(std::string_view description, size_t maxlen)
{
auto len = std::size(description);
if (len > maxlen)
{
description.remove_suffix(len - maxlen);
auto const pos = description.rfind(' ');
len = pos != std::string_view::npos ? pos : maxlen;
}
return len;
}
static void getopts_usage_line(tr_option const* opt, int longWidth, int shortWidth, int argWidth)
{
char const* longName = opt->longName != nullptr ? opt->longName : "";
char const* shortName = opt->shortName != nullptr ? opt->shortName : "";
char const* arg = getArgName(opt);
int const d_indent = shortWidth + longWidth + argWidth + 7;
int const d_width = 80 - d_indent;
auto d = std::string_view{ opt->description };
printf(
" %s%-*s %s%-*s %-*s ",
tr_str_is_empty(shortName) ? " " : "-",
TR_ARG_TUPLE(shortWidth, shortName),
tr_str_is_empty(longName) ? " " : "--",
TR_ARG_TUPLE(longWidth, longName),
TR_ARG_TUPLE(argWidth, arg));
auto const strip_leading_whitespace = [](std::string_view text)
{
auto pos = text.find_first_not_of(' ');
if (pos != std::string_view::npos)
{
text.remove_prefix(pos);
}
return text;
};
int len = get_next_line_len(d, d_width);
printf("%*.*s\n", TR_ARG_TUPLE(len, len, std::data(d)));
d.remove_prefix(len);
d = strip_leading_whitespace(d);
while ((len = get_next_line_len(d, d_width)) != 0)
{
printf("%*.*s%*.*s\n", TR_ARG_TUPLE(d_indent, d_indent, ""), TR_ARG_TUPLE(len, len, std::data(d)));
d.remove_prefix(len);
d = strip_leading_whitespace(d);
}
}
static void maxWidth(struct tr_option const* o, size_t& longWidth, size_t& shortWidth, size_t& argWidth)
{
if (o->longName != nullptr)
{
longWidth = std::max(longWidth, strlen(o->longName));
}
if (o->shortName != nullptr)
{
shortWidth = std::max(shortWidth, strlen(o->shortName));
}
char const* const arg = getArgName(o);
if (arg != nullptr)
{
argWidth = std::max(argWidth, strlen(arg));
}
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}
void tr_getopt_usage(char const* progName, char const* description, struct tr_option const opts[])
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{
auto longWidth = size_t{ 0 };
auto shortWidth = size_t{ 0 };
auto argWidth = size_t{ 0 };
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for (tr_option const* o = opts; o->val != 0; ++o)
{
maxWidth(o, longWidth, shortWidth, argWidth);
}
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auto const help = tr_option{ -1, "help", "Display this help page and exit", "h", false, nullptr };
maxWidth(&help, longWidth, shortWidth, argWidth);
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if (description == nullptr)
{
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description = "Usage: %s [options]";
}
printf(description, progName);
printf("\n\nOptions:\n");
getopts_usage_line(&help, longWidth, shortWidth, argWidth);
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for (tr_option const* o = opts; o->val != 0; ++o)
{
getopts_usage_line(o, longWidth, shortWidth, argWidth);
}
}
static tr_option const* findOption(tr_option const* opts, char const* str, char const** setme_arg)
{
size_t matchlen = 0;
char const* arg = nullptr;
tr_option const* match = nullptr;
/* find the longest matching option */
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for (tr_option const* o = opts; o->val != 0; ++o)
{
size_t len = o->longName != nullptr ? strlen(o->longName) : 0;
if (matchlen < len && str[0] == '-' && str[1] == '-' && strncmp(str + 2, o->longName, len) == 0 &&
(str[len + 2] == '\0' || (o->has_arg && str[len + 2] == '=')))
{
matchlen = len;
match = o;
arg = str[len + 2] == '=' ? str + len + 3 : nullptr;
}
len = o->shortName != nullptr ? strlen(o->shortName) : 0;
if (matchlen < len && str[0] == '-' && strncmp(str + 1, o->shortName, len) == 0 && (str[len + 1] == '\0' || o->has_arg))
{
matchlen = len;
match = o;
switch (str[len + 1])
{
case '\0':
arg = nullptr;
break;
case '=':
arg = str + len + 2;
break;
default:
arg = str + len + 1;
break;
}
}
}
if (setme_arg != nullptr)
{
*setme_arg = arg;
}
return match;
}
int tr_getopt(char const* usage, int argc, char const* const* argv, tr_option const* opts, char const** setme_optarg)
{
char const* arg = nullptr;
tr_option const* o = nullptr;
*setme_optarg = nullptr;
/* handle the builtin 'help' option */
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for (int i = 1; i < argc; ++i)
{
if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0)
{
tr_getopt_usage(argv[0], usage, opts);
exit(0);
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}
}
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/* out of options? */
if (argc == 1 || tr_optind >= argc)
{
return TR_OPT_DONE;
}
o = findOption(opts, argv[tr_optind], &arg);
if (o == nullptr)
{
/* let the user know we got an unknown option... */
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*setme_optarg = argv[tr_optind++];
return TR_OPT_UNK;
}
if (!o->has_arg)
{
/* no argument needed for this option, so we're done */
if (arg != nullptr)
{
return TR_OPT_ERR;
}
*setme_optarg = nullptr;
++tr_optind;
return o->val;
}
/* option needed an argument, and it was embedded in this string */
if (arg != nullptr)
{
*setme_optarg = arg;
++tr_optind;
return o->val;
}
/* throw an error if the option needed an argument but didn't get one */
if (++tr_optind >= argc)
{
return TR_OPT_ERR;
}
if (findOption(opts, argv[tr_optind], nullptr) != nullptr)
{
return TR_OPT_ERR;
}
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*setme_optarg = argv[tr_optind++];
return o->val;
}