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AK/Userland: Add single value to ArgsParser usage, and port tail to use ArgsParser

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This commit is contained in:
Robin Burchell 2019-05-17 12:59:37 +02:00 • committed by Andreas Kling
parent c478503581
commit 6dd7ee53ea
3 changed files with 61 additions and 30 deletions
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55
Userland/tail.cpp
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@ -2,17 +2,11 @@
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <getopt.h>
#include <unistd.h>
#include <AK/Assertions.h>
#include <AK/ArgsParser.h>
#include <LibCore/CFile.h>
static void print_usage_and_exit()
{
printf("usage: tail [-f, -n <linecount>] <filename>\n");
exit(1);
}
int tail_from_pos(CFile& file, off_t startline, bool want_follow)
{
if (!file.seek(startline + 1))
@ -81,37 +75,38 @@ static void exit_because_we_wanted_lines()
int main(int argc, char *argv[])
{
AK::ArgsParser args_parser("tail");
args_parser.add_arg("f", "follow -- appended data is output as it is written to the file");
args_parser.add_arg("n", "lines", "fetch the specified number of lines");
args_parser.set_required_single_value("file");
AK::ArgsParserResult args = args_parser.parse(argc, (const char**)argv);
Vector<String> values = args.get_single_values();
if (values.size() != 1) {
args_parser.print_usage();
return -1;
}
int line_count = 0;
bool flag_follow = false;
int opt;
while ((opt = getopt(argc, argv, "fn:")) != -1) {
switch (opt) {
case 'f':
flag_follow = true;
break;
case 'n':
line_count = strtol(optarg, NULL, 10);
if (errno == EINVAL) {
exit_because_we_wanted_lines();
}
break;
default:
print_usage_and_exit();
if (args.is_present("n")) {
line_count = strtol(args.get("n").characters(), NULL, 10);
if (errno == EINVAL) {
args_parser.print_usage();
return -1;
}
}
const char *path = nullptr;
if (optind >= argc) {
print_usage_and_exit();
}
path = argv[optind];
CFile f(path);
CFile f(values[0]);
if (!f.open(CIODevice::ReadOnly)) {
fprintf(stderr, "Error opening file %s: %s\n", path, strerror(errno));
fprintf(stderr, "Error opening file %s: %s\n", f.filename().characters(), strerror(errno));
exit(-1);
}
bool flag_follow = args.is_present("f");
bool o_arg = args.is_present("o");
auto pos = find_seek_pos(f, line_count);
return tail_from_pos(f, pos, flag_follow);
}