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d9a9f23d0b
This adds support for two new diff algorithms, Myers diff and Patience diff. These algorithms perform a different form of search compared to the classic Stone algorithm and support escapes when worst case scenarios are encountered. Add the -A flag to allow selection of the algorithm, but default to using the new Myers diff implementation. The libdiff implementation currently only supports a subset of input and output options supported by diff. When these options are used, but the algorithm is not selected, automatically fallback to the classic Stone algorithm until support for these modes can be added. Based on work originally done by thj@ with contributions from kevans@. Sponsored by: Klara, Inc. Reviewed by: thj Differential Revision: https://reviews.freebsd.org/D44302
123 lines
3.2 KiB
C
123 lines
3.2 KiB
C
/*-
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* Copyright (c) 2017 Baptiste Daroussin <bapt@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/procdesc.h>
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#include <sys/wait.h>
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#include <err.h>
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#include <paths.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "pr.h"
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#include "diff.h"
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#include "xmalloc.h"
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#define _PATH_PR "/usr/bin/pr"
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struct pr *
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start_pr(char *file1, char *file2)
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{
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int pfd[2];
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int pr_pd;
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pid_t pid;
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char *header;
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struct pr *pr;
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pr = xcalloc(1, sizeof(*pr));
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xasprintf(&header, "%s %s %s", diffargs, file1, file2);
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signal(SIGPIPE, SIG_IGN);
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fflush(stdout);
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rewind(stdout);
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if (pipe(pfd) == -1)
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err(2, "pipe");
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switch ((pid = pdfork(&pr_pd, PD_CLOEXEC))) {
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case -1:
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status |= 2;
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free(header);
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err(2, "No more processes");
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case 0:
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/* child */
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if (pfd[0] != STDIN_FILENO) {
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dup2(pfd[0], STDIN_FILENO);
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close(pfd[0]);
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}
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close(pfd[1]);
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execl(_PATH_PR, _PATH_PR, "-h", header, (char *)0);
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_exit(127);
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default:
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/* parent */
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if (pfd[1] != STDOUT_FILENO) {
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pr->ostdout = dup(STDOUT_FILENO);
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dup2(pfd[1], STDOUT_FILENO);
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close(pfd[1]);
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}
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close(pfd[0]);
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rewind(stdout);
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free(header);
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pr->kq = kqueue();
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if (pr->kq == -1)
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err(2, "kqueue");
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pr->e = xmalloc(sizeof(struct kevent));
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EV_SET(pr->e, pr_pd, EVFILT_PROCDESC, EV_ADD, NOTE_EXIT, 0,
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NULL);
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if (kevent(pr->kq, pr->e, 1, NULL, 0, NULL) == -1)
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err(2, "kevent");
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}
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return (pr);
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}
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/* close the pipe to pr and restore stdout */
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void
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stop_pr(struct pr *pr)
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{
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int wstatus;
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if (pr == NULL)
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return;
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fflush(stdout);
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if (pr->ostdout != STDOUT_FILENO) {
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close(STDOUT_FILENO);
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dup2(pr->ostdout, STDOUT_FILENO);
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close(pr->ostdout);
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}
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if (kevent(pr->kq, NULL, 0, pr->e, 1, NULL) == -1)
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err(2, "kevent");
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wstatus = pr->e[0].data;
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close(pr->kq);
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free(pr);
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if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus) != 0)
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errx(2, "pr exited abnormally");
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else if (WIFSIGNALED(wstatus))
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errx(2, "pr killed by signal %d",
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WTERMSIG(wstatus));
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}
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