diff options
| -rw-r--r-- | .gitignore | 15 | ||||
| -rw-r--r-- | LICENSE | 15 | ||||
| -rw-r--r-- | Makefile | 37 | ||||
| -rw-r--r-- | config.mk | 8 | ||||
| -rw-r--r-- | git-rediff.c | 659 |
5 files changed, 734 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..0ec616b --- /dev/null +++ b/.gitignore @@ -0,0 +1,15 @@ +*\#* +*~ +*.o +*.a +*.lo +*.su +*.so +*.so.* +*.dll +*.dylib +*.gch +*.gcov +*.gcno +*.gcda +/git-rediff @@ -0,0 +1,15 @@ +ISC License + +© 2024 Mattias Andrée <maandree@kth.se> + +Permission to use, copy, modify, and/or distribute this software for any +purpose with or without fee is hereby granted, provided that the above +copyright notice and this permission notice appear in all copies. + +THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..803a6e7 --- /dev/null +++ b/Makefile @@ -0,0 +1,37 @@ +.POSIX: + +CONFIGFILE = config.mk +include $(CONFIGFILE) + +OBJ =\ + git-rediff.o + +HDR = + +all: git-rediff +$(OBJ): $(HDR) + +.c.o: + $(CC) -c -o $@ $< $(CFLAGS) $(CPPFLAGS) + +git-rediff: $(OBJ) + $(CC) -o $@ $(OBJ) $(LDFLAGS) + +install: git-rediff + mkdir -p -- "$(DESTDIR)$(PREFIX)/bin" + mkdir -p -- "$(DESTDIR)$(MANPREFIX)/man1/" + cp -- git-rediff "$(DESTDIR)$(PREFIX)/bin/" + cp -- git-rediff.1 "$(DESTDIR)$(MANPREFIX)/man1/" + +uninstall: + -rm -f -- "$(DESTDIR)$(PREFIX)/bin/git-rediff" + -rm -f -- "$(DESTDIR)$(MANPREFIX)/man1/git-rediff.1" + +clean: + -rm -f -- *.o *.a *.lo *.su *.so *.so.* *.gch *.gcov *.gcno *.gcda + -rm -f -- git-rediff + +.SUFFIXES: +.SUFFIXES: .o .c + +.PHONY: all install uninstall clean diff --git a/config.mk b/config.mk new file mode 100644 index 0000000..aeb8cec --- /dev/null +++ b/config.mk @@ -0,0 +1,8 @@ +PREFIX = /usr +MANPREFIX = $(PREFIX)/share/man + +CC = c99 + +CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_GNU_SOURCE +CFLAGS = +LDFLAGS = -lsimple diff --git a/git-rediff.c b/git-rediff.c new file mode 100644 index 0000000..07629ef --- /dev/null +++ b/git-rediff.c @@ -0,0 +1,659 @@ +/* See LICENSE file for copyright and license details. */ +#ifdef __linux__ +# include <linux/prctl.h> +# include <sys/prctl.h> +#endif +#include <libsimple.h> +#include <libsimple-arg.h> + +USAGE("[file] ..."); + +#if defined(__clang__) +# pragma clang diagnostic ignored "-Wunsafe-buffer-usage" +#endif + +enum successfulness { + MERGED = 0, + CONFLICT = 1, + ERROR = 2 +}; + +struct line { + union { + size_t in_off; + const unsigned char *in; + }; + const char *text; + size_t len; +}; + +struct text { + struct line *lines; + size_t nlines; + size_t lines_size; +}; + +struct subhunk { + union { + struct line *head; + unsigned char *in; + }; + struct text text; +}; + +struct hunk { + struct subhunk *subs; + size_t nsubs; +}; + +static int +send_line(int fd, const char *fname, const struct line *line) +{ + size_t off = 0; + ssize_t r; + while (off < line->len) { + r = write(fd, &line->text[off], line->len - off); + if (r < 0) { + if (errno == EINTR) + continue; + weprintf("write %s:", fname); + return -1; + } + off += (size_t)r; + } + return 0; +} + +static int +send_text(int fd, const char *fname, const struct text *text) +{ + size_t i; + for (i = 0; i < text->nlines; i++) + if (send_line(fd, fname, &text->lines[i])) + return -1; + return 0; +} + +static void +ensure_nonstandard(int *fdp) +{ + int r; + if (*fdp > 2) + return; + r = fcntl(*fdp, F_DUPFD, 3); + if (r < 3) + eprintf("fcntl <pipe> F_DUPFD 3:"); + *fdp = r; +} + +#if defined(__GNUC__) +__attribute__((__pure__)) +#endif +static int +in_all(const unsigned char *in, size_t full_bytes, unsigned char last_byte) +{ + while (full_bytes--) + if (!(~*in++ & ((1U << CHAR_BIT) - 1U))) + return 0; + return *in == last_byte; +} + +static int +line_startswith(struct line *line, const char *head) +{ + size_t len = strlen(head); + return line->len >= len && !strncmp(line->text, head, len); +} + +static void +append_lines(struct text *textp, const struct line *lines, size_t n) +{ + if (n > textp->lines_size - textp->nlines) { + textp->lines_size = textp->nlines + n; + textp->lines = ereallocarray(textp->lines, textp->lines_size, sizeof(*textp->lines)); + } + memcpy(&textp->lines[textp->nlines], lines, n * sizeof(*lines)); + textp->nlines += n; +} + +static void +append_line(struct text *textp, const struct line *line) +{ + append_lines(textp, line, 1U); +} + +static void +append_text(struct text *textp, const struct text *text) +{ + append_lines(textp, text->lines, text->nlines); +} + +static char * +diff_subhunks(const struct subhunk *f1, const struct subhunk *f2) +{ + size_t context = MAX(f1->text.nlines, f2->text.nlines); + pid_t pid1, pid2, piddiff; + int pipe1[2], pipe2[2], pipediff[2]; + char *ret = NULL; + size_t ret_size = 0; + size_t ret_off = 0; + int status; + size_t i, n; + int rem, ret_next = 0; + ssize_t r; + union { + struct { + char context[sizeof("-U") + 3 * sizeof(context)]; + char pipe1[sizeof("/dev/fd/-") + 3 * sizeof(pipe1[0])]; + char pipe2[sizeof("/dev/fd/-") + 3 * sizeof(pipe2[0])]; + }; + char text[8096]; + } buf; + + if (pipe(pipediff)) + eprintf("pipe:"); + if (pipe(pipe1)) + eprintf("pipe:"); + if (pipe(pipe2)) + eprintf("pipe:"); + + ensure_nonstandard(&pipe2[0]); + ensure_nonstandard(&pipe1[0]); + + pid1 = fork(); + if (pid1 < 0) + eprintf("fork:"); + if (pid1 == 0) { + close(pipediff[0]); + close(pipediff[1]); + close(pipe1[0]); + close(pipe2[0]); + close(pipe2[1]); + if (send_text(pipe1[1], "<pipe>", &f1->text)) + _exit(1); + close(pipe1[1]); + _exit(0); + } + + pid2 = fork(); + if (pid2 < 0) + eprintf("fork:"); + if (pid2 == 0) { + close(pipediff[0]); + close(pipediff[1]); + close(pipe2[0]); + close(pipe1[0]); + close(pipe1[1]); + if (send_text(pipe2[1], "<pipe>", &f2->text)) + _exit(1); + close(pipe2[1]); + _exit(0); + } + + close(pipe1[1]); + close(pipe2[1]); + + piddiff = fork(); + if (piddiff < 0) + eprintf("fork:"); + if (piddiff == 0) { + close(pipediff[0]); + if (pipediff[1] != STDOUT_FILENO) { + if (dup2(pipediff[1], STDOUT_FILENO) != STDOUT_FILENO) + eprintf("dup2 <pipe> <stdout>:"); + close(pipediff[1]); + } + sprintf(buf.context, "-U%zu", context); + sprintf(buf.pipe1, "/dev/fd/%i", pipe1[0]); + sprintf(buf.pipe2, "/dev/fd/%i", pipe2[0]); +#ifdef PR_SET_PDEATHSIG + prctl(PR_SET_PDEATHSIG, SIGKILL); +#endif + execlp("diff", "diff", buf.context, "--", buf.pipe1, buf.pipe2, NULL); + _exit(125); + } + + close(pipediff[1]); + close(pipe1[0]); + close(pipe2[0]); + + rem = 3; + for (;;) { + r = read(pipediff[0], buf.text, sizeof(buf.text)); + if (r <= 0) { + if (!r) + break; + if (errno == EINTR) + continue; + eprintf("read <diff(1) subprocess stdout pipe>:"); + } + n = (size_t)r; + for (i = 0; i < n; i++) { + if (ret_next) { + ret_next = 0; + if (ret_off == ret_size) { + if (ret_size > SIZE_MAX - 512) { + errno = ENOMEM; + eprintf("realloc:"); + } + ret = erealloc(ret, ret_size += 512); + } + ret[ret_off++] = buf.text[i]; + } else if (buf.text[i] == '\n') { + if (rem) { + if (!--rem) + ret_next = 1; + continue; + } + ret_next = 1; + } + } + } + + if (waitpid(pid1, &status, 0) != pid1) + eprintf("waitpid <file sender subprocess> 0:"); + if (status) + eprintf("waitpid <file sender subprocess> 0: process exited abnormally"); + + if (waitpid(pid2, &status, 0) != pid2) + eprintf("waitpid <file sender subprocess> 0:"); + if (status) + eprintf("waitpid <file sender subprocess> 0: process exited abnormally"); + + if (waitpid(piddiff, &status, 0) != piddiff) + eprintf("waitpid <diff(1) subprocess> 0:"); + if (status == 0) { + ret = erealloc(ret, f1->text.nlines + 1U); + memset(ret, ' ', f1->text.nlines); + } else if (WIFEXITED(status) && WEXITSTATUS(status) == 1) { + ret = erealloc(ret, ret_off + 1U); + } else { + eprintf("waitpid <diff(1) subprocess> 0: process exited abnormally"); + } + ret[ret_off] = '\0'; + return ret; +} + +static void +diff_hunk(struct subhunk *ret, const struct hunk *hunk) +{ + char *diff, *p; + size_t k, i, j, in_size = 0, in_off = 0; + size_t in_step, bit_off; + unsigned char bit; + struct subhunk ret_buf, ret_tmp; + + in_step = hunk->nsubs / CHAR_BIT; + in_step += (size_t)!!(hunk->nsubs % CHAR_BIT); + + bit = (unsigned char)1; + bit_off = 0; + ret->text.lines_size = ret->text.nlines = hunk->subs[0].text.nlines; + in_size = ret->text.nlines * in_step; + ret->in = emalloc(in_size); + ret->text.lines = ecalloc(ret->text.lines_size, sizeof(*ret->text.lines)); + memcpy(ret->text.lines, hunk->subs[0].text.lines, ret->text.nlines * sizeof(*hunk->subs[0].text.lines)); + memset(ret->in, 0, in_size); + for (i = 0; i < ret->text.nlines; i++) { + ret->text.lines[i].in_off = in_off; + ret->in[in_off + bit_off] = bit; + in_off += in_step; + } + + ret_buf.in = ret->in; + ret_buf.text.lines = NULL; + ret_buf.text.lines_size = 0; + + for (k = 1; k < hunk->nsubs; k++) { + bit <<= 1; + if (!bit) { + bit = (unsigned char)1; + bit_off += 1; + } + diff = diff_subhunks(ret, &hunk->subs[k]); + i = j = 0; + ret_buf.text.nlines = 0; + for (p = diff; *p; p++) { + if (*p == '-') { + append_line(&ret_buf.text, &ret->text.lines[i]); + i++; + } else if (*p == '+') { + append_line(&ret_buf.text, &hunk->subs[k].text.lines[j]); + if (in_off == in_size) { + if (in_step > (SIZE_MAX - in_size) / 16U) { + errno = ENOMEM; + eprintf("realloc:"); + } + in_size += 16U * in_step; + ret_buf.in = ret->in = erealloc(ret->in, in_size); + memset(&ret->in[in_off], 0, in_size - in_off); + } + ret_buf.text.lines[ret_buf.text.nlines - 1U].in_off = in_off; + ret_buf.in[ret_buf.text.lines[ret_buf.text.nlines - 1U].in_off + bit_off] = bit; + in_off += in_step; + j++; + } else if (*p == ' ') { + append_line(&ret_buf.text, &ret->text.lines[i]); + ret_buf.in[ret_buf.text.lines[ret_buf.text.nlines - 1U].in_off + bit_off] |= bit; + i++; + j++; + } else { + eprintf("output of diff(1) was corrupted"); + } + } + ret->text.nlines = ret_buf.text.nlines; + ret_tmp.text = ret->text; + ret->text = ret_buf.text; + ret_buf.text = ret_tmp.text; + free(diff); + } + + for (i = 0; i < ret->text.nlines; i++) + ret->text.lines[i].in = &ret->in[ret->text.lines[i].in_off]; + + free(ret_buf.text.lines); +} + +static enum successfulness +rediff_hunk(struct text *resp, const struct hunk *hunk, const struct line *tail) +{ + struct subhunk diff; + size_t i, j, full_bytes; + unsigned char last_byte; + struct hunk uncommon; + int in_uncommon = 0; + enum successfulness ret = MERGED; + + full_bytes = hunk->nsubs / CHAR_BIT; + last_byte = 0; + if (hunk->nsubs % CHAR_BIT) { + last_byte = (unsigned char)(1U << ((hunk->nsubs % CHAR_BIT) - 1U)); + last_byte |= (unsigned char)(last_byte - 1U); + } + + uncommon.nsubs = hunk->nsubs; + uncommon.subs = ecalloc(uncommon.nsubs, sizeof(*uncommon.subs)); + for (i = 0; i < uncommon.nsubs; i++) { + uncommon.subs[i].head = hunk->subs[i].head; + uncommon.subs[i].text.lines = NULL; + uncommon.subs[i].text.nlines = 0; + uncommon.subs[i].text.lines_size = 0; + } + + diff_hunk(&diff, hunk); + for (i = 0; i < diff.text.nlines; i++) { + if (in_all(diff.text.lines[i].in, full_bytes, last_byte)) { + if (in_uncommon) { + for (j = 0; j < uncommon.nsubs; j++) { + append_line(resp, uncommon.subs[j].head); + append_text(resp, &uncommon.subs[j].text); + } + append_line(resp, tail); + in_uncommon = 0; + } + append_line(resp, &diff.text.lines[i]); + } else { + if (!in_uncommon) { + in_uncommon = 1; + for (j = 0; j < uncommon.nsubs; j++) + uncommon.subs[j].text.nlines = 0; + } + ret = CONFLICT; + for (j = 0; j < uncommon.nsubs; j++) + if ((diff.text.lines[i].in[j / CHAR_BIT] >> (j % CHAR_BIT)) & 1U) + append_line(&uncommon.subs[j].text, &diff.text.lines[i]); + } + } + + if (in_uncommon) { + for (j = 0; j < uncommon.nsubs; j++) { + append_line(resp, uncommon.subs[j].head); + append_text(resp, &uncommon.subs[j].text); + } + append_line(resp, tail); + } + + free(diff.in); + free(diff.text.lines); + for (i = 0; i < uncommon.nsubs; i++) + free(uncommon.subs[i].text.lines); + free(uncommon.subs); + + return ret; +} + +static enum successfulness +rediff_file(struct text *text_out, const struct text *text_in, const char *fname) +{ + size_t i, t; + struct hunk hunk = {0}; + ssize_t subhunk = -1; + enum successfulness ret = MERGED, r; + + *text_out = (struct text){0}; + + for (i = 0; i < text_in->nlines; i++) { + if (line_startswith(&text_in->lines[i], "<<<<<<<")) { + if (subhunk >= 0) + goto syntax_error; + goto new_subhunk; + } else if (line_startswith(&text_in->lines[i], "|||||||") || line_startswith(&text_in->lines[i], "=======")) { + if (subhunk < 0) + goto syntax_error; + if (!line_startswith(hunk.subs[subhunk].head, "<<<<<<<") && + !line_startswith(hunk.subs[subhunk].head, "|||||||")) + goto syntax_error; + new_subhunk: + subhunk++; + if ((size_t)subhunk == hunk.nsubs) + hunk.subs = ereallocarray(hunk.subs, ++hunk.nsubs, sizeof(*hunk.subs)); + hunk.subs[subhunk].text.nlines = 0; + hunk.subs[subhunk].head = &text_in->lines[i]; + } else if (line_startswith(&text_in->lines[i], ">>>>>>>")) { + if (subhunk < 0) + goto syntax_error; + if (!line_startswith(hunk.subs[subhunk].head, "=======")) + goto syntax_error; + t = hunk.nsubs; + hunk.nsubs = (size_t)subhunk + 1U; + r = rediff_hunk(text_out, &hunk, &text_in->lines[i]); + ret = MAX(ret, r); + hunk.nsubs = t; + subhunk = -1; + } else { + if (subhunk < 0) + append_line(text_out, &text_in->lines[i]); + else + append_line(&hunk.subs[subhunk].text, &text_in->lines[i]); + } + } + + if (subhunk >= 0) { + weprintf("file %s is truncated", fname); + error: + ret = ERROR; + } + + for (i = 0; i < hunk.nsubs; i++) + free(hunk.subs[i].text.lines); + free(hunk.subs); + + return ret; + +syntax_error: + weprintf("syntax error at %s:%zu", fname, i + 1U); + goto error; +} + +static int +read_lines(struct text *lines_out, char **text_out, int fd, const char *fname) +{ + struct line *lines; + size_t text_len = 0; + size_t text_size = 0; + ssize_t r; + void *new; + size_t i; + + *lines_out = (struct text){0}; + *text_out = NULL; + + for (;;) { + if (text_len == text_size) { + if (text_size > SIZE_MAX - 8096U) { + errno = ENOMEM; + weprintf("realloc:"); + goto fail; + } + text_size += 8096U; + new = realloc(*text_out, text_size); + if (!new) + goto fail; + *text_out = new; + } + r = read(fd, &(*text_out)[text_len], text_size - text_len); + if (r <= 0) { + if (!r) + break; + if (errno == EINTR) + continue; + weprintf("read %s:", fname); + goto fail; + } + text_len += (size_t)r; + } + + lines_out->nlines = (text_len ? 1U : 0U); + for (i = 0; i + 1U < text_len; i++) + if ((*text_out)[i] == '\n') + lines_out->nlines += 1U; + + if (!lines_out->nlines) + return 0; + + lines = lines_out->lines = ecalloc(lines_out->nlines, sizeof(*lines_out->lines)); + + for (i = 0; i < lines_out->nlines; i++) + lines[i].in = NULL; + + lines->text = *text_out; + lines++; + for (i = 0; i + 1U < text_len;) { + if ((*text_out)[i++] == '\n') { + lines->text = &(*text_out)[i]; + lines[-1].len = (size_t)(lines->text - lines[-1].text); + lines++; + } + } + lines[-1].len = (size_t)(&(*text_out)[text_len] - lines[-1].text); + + return 0; + +fail: + free(*text_out); + *text_out = NULL; + return -1; +} + +static enum successfulness +rediff(const char *fname) +{ + struct text text_in, text_out; + char *text; + int fd, close_fd; + enum successfulness ret; + + if (!strcmp(fname, "-")) { + fname = "<stdout>"; + close_fd = 0; + fd = STDOUT_FILENO; + if (read_lines(&text_in, &text, STDIN_FILENO, "<stdin>")) + return ERROR; + } else { + close_fd = 1; + fd = open(fname, O_RDWR); + if (fd < 0) { + weprintf("open %s O_RDWR:", fname); + return ERROR; + } + if (read_lines(&text_in, &text, fd, "<stdin>")) { + close(fd); + return ERROR; + } + if (lseek(fd, 0, SEEK_SET) != 0) { + weprintf("lseek %s 0 SEEK_SET:", fname); + return ERROR; + } + } + + ret = rediff_file(&text_out, &text_in, fname); + if (ret == ERROR) { + ret = ERROR; + goto out; + } + + if (send_text(fd, fname, &text_out)) { + ret = ERROR; + goto out; + } + + if (close_fd) { + off_t length = lseek(fd, 0, SEEK_CUR); + if (length < 0) { + weprintf("lseek %s 0 SEEK_CUR:", fname); + ret = ERROR; + goto out; + } + if (ftruncate(fd, length)) { + weprintf("ftruncate %s <current position>:", fname); + ret = ERROR; + goto out; + } + } + +out: + if (close_fd) + close(fd); + free(text_out.lines); + free(text_in.lines); + free(text); + return ret; +} + +int +main(int argc, char *argv[]) +{ + enum successfulness ret = 0, r; + + libsimple_default_failure_exit = 2; + + ARGBEGIN { + default: + usage(); + } ARGEND; + + if (fstat(STDERR_FILENO, &(struct stat){0})) { + int fd; + if (errno != EBADF) + eprintf("fstat <stderr>:"); + fd = open("/dev/null", O_WRONLY); + if (fd < 0) + eprintf("open /dev/null O_WRONLY:"); + if (fd != STDERR_FILENO) { + if (dup2(fd, STDERR_FILENO) != STDERR_FILENO) + eprintf("dup2 /dev/null <stderr>:"); + close(fd); + } + } + + if (argc) { + for (; *argv; argv++) { + r = rediff(*argv); + ret = MAX(ret, r); + } + } else { + ret = rediff("-"); + } + + return (int)ret; +} |