git/xdiff/xmerge.c

687 строки
17 KiB
C
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/*
* LibXDiff by Davide Libenzi ( File Differential Library )
* Copyright (C) 2003-2006 Davide Libenzi, Johannes E. Schindelin
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see
* <http://www.gnu.org/licenses/>.
*
* Davide Libenzi <davidel@xmailserver.org>
*
*/
#include "xinclude.h"
typedef struct s_xdmerge {
struct s_xdmerge *next;
/*
* 0 = conflict,
* 1 = no conflict, take first,
* 2 = no conflict, take second.
* 3 = no conflict, take both.
*/
int mode;
/*
* These point at the respective postimages. E.g. <i1,chg1> is
* how side #1 wants to change the common ancestor; if there is no
* overlap, lines before i1 in the postimage of side #1 appear
* in the merge result as a region touched by neither side.
*/
long i1, i2;
long chg1, chg2;
/*
* These point at the preimage; of course there is just one
* preimage, that is from the shared common ancestor.
*/
long i0;
long chg0;
} xdmerge_t;
static int xdl_append_merge(xdmerge_t **merge, int mode,
long i0, long chg0,
long i1, long chg1,
long i2, long chg2)
{
xdmerge_t *m = *merge;
if (m && (i1 <= m->i1 + m->chg1 || i2 <= m->i2 + m->chg2)) {
if (mode != m->mode)
m->mode = 0;
m->chg0 = i0 + chg0 - m->i0;
m->chg1 = i1 + chg1 - m->i1;
m->chg2 = i2 + chg2 - m->i2;
} else {
m = xdl_malloc(sizeof(xdmerge_t));
if (!m)
return -1;
m->next = NULL;
m->mode = mode;
m->i0 = i0;
m->chg0 = chg0;
m->i1 = i1;
m->chg1 = chg1;
m->i2 = i2;
m->chg2 = chg2;
if (*merge)
(*merge)->next = m;
*merge = m;
}
return 0;
}
static int xdl_cleanup_merge(xdmerge_t *c)
{
int count = 0;
xdmerge_t *next_c;
/* were there conflicts? */
for (; c; c = next_c) {
if (c->mode == 0)
count++;
next_c = c->next;
free(c);
}
return count;
}
static int xdl_merge_cmp_lines(xdfenv_t *xe1, int i1, xdfenv_t *xe2, int i2,
int line_count, long flags)
{
int i;
xrecord_t **rec1 = xe1->xdf2.recs + i1;
xrecord_t **rec2 = xe2->xdf2.recs + i2;
for (i = 0; i < line_count; i++) {
int result = xdl_recmatch(rec1[i]->ptr, rec1[i]->size,
rec2[i]->ptr, rec2[i]->size, flags);
if (!result)
return -1;
}
return 0;
}
static int xdl_recs_copy_0(int use_orig, xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
{
xrecord_t **recs;
int size = 0;
recs = (use_orig ? xe->xdf1.recs : xe->xdf2.recs) + i;
if (count < 1)
return 0;
for (i = 0; i < count; size += recs[i++]->size)
if (dest)
memcpy(dest + size, recs[i]->ptr, recs[i]->size);
if (add_nl) {
i = recs[count - 1]->size;
if (i == 0 || recs[count - 1]->ptr[i - 1] != '\n') {
if (needs_cr) {
if (dest)
dest[size] = '\r';
size++;
}
if (dest)
dest[size] = '\n';
size++;
}
}
return size;
}
static int xdl_recs_copy(xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
{
return xdl_recs_copy_0(0, xe, i, count, needs_cr, add_nl, dest);
}
static int xdl_orig_copy(xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
{
return xdl_recs_copy_0(1, xe, i, count, needs_cr, add_nl, dest);
}
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
/*
* Returns 1 if the i'th line ends in CR/LF (if it is the last line and
* has no eol, the preceding line, if any), 0 if it ends in LF-only, and
* -1 if the line ending cannot be determined.
*/
static int is_eol_crlf(xdfile_t *file, int i)
{
long size;
if (i < file->nrec - 1)
/* All lines before the last *must* end in LF */
return (size = file->recs[i]->size) > 1 &&
file->recs[i]->ptr[size - 2] == '\r';
if (!file->nrec)
/* Cannot determine eol style from empty file */
return -1;
if ((size = file->recs[i]->size) &&
file->recs[i]->ptr[size - 1] == '\n')
/* Last line; ends in LF; Is it CR/LF? */
return size > 1 &&
file->recs[i]->ptr[size - 2] == '\r';
if (!i)
/* The only line has no eol */
return -1;
/* Determine eol from second-to-last line */
return (size = file->recs[i - 1]->size) > 1 &&
file->recs[i - 1]->ptr[size - 2] == '\r';
}
static int is_cr_needed(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m)
{
int needs_cr;
/* Match post-images' preceding, or first, lines' end-of-line style */
needs_cr = is_eol_crlf(&xe1->xdf2, m->i1 ? m->i1 - 1 : 0);
if (needs_cr)
needs_cr = is_eol_crlf(&xe2->xdf2, m->i2 ? m->i2 - 1 : 0);
/* Look at pre-image's first line, unless we already settled on LF */
if (needs_cr)
needs_cr = is_eol_crlf(&xe1->xdf1, 0);
/* If still undecided, use LF-only */
return needs_cr < 0 ? 0 : needs_cr;
}
static int fill_conflict_hunk(xdfenv_t *xe1, const char *name1,
xdfenv_t *xe2, const char *name2,
const char *name3,
int size, int i, int style,
xdmerge_t *m, char *dest, int marker_size)
{
int marker1_size = (name1 ? strlen(name1) + 1 : 0);
int marker2_size = (name2 ? strlen(name2) + 1 : 0);
int marker3_size = (name3 ? strlen(name3) + 1 : 0);
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
int needs_cr = is_cr_needed(xe1, xe2, m);
if (marker_size <= 0)
marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
/* Before conflicting part */
size += xdl_recs_copy(xe1, i, m->i1 - i, 0, 0,
dest ? dest + size : NULL);
if (!dest) {
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
size += marker_size + 1 + needs_cr + marker1_size;
} else {
memset(dest + size, '<', marker_size);
size += marker_size;
if (marker1_size) {
dest[size] = ' ';
memcpy(dest + size + 1, name1, marker1_size - 1);
size += marker1_size;
}
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
if (needs_cr)
dest[size++] = '\r';
dest[size++] = '\n';
}
/* Postimage from side #1 */
size += xdl_recs_copy(xe1, m->i1, m->chg1, needs_cr, 1,
dest ? dest + size : NULL);
if (style == XDL_MERGE_DIFF3) {
/* Shared preimage */
if (!dest) {
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
size += marker_size + 1 + needs_cr + marker3_size;
} else {
memset(dest + size, '|', marker_size);
size += marker_size;
if (marker3_size) {
dest[size] = ' ';
memcpy(dest + size + 1, name3, marker3_size - 1);
size += marker3_size;
}
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
if (needs_cr)
dest[size++] = '\r';
dest[size++] = '\n';
}
size += xdl_orig_copy(xe1, m->i0, m->chg0, needs_cr, 1,
dest ? dest + size : NULL);
}
if (!dest) {
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
size += marker_size + 1 + needs_cr;
} else {
memset(dest + size, '=', marker_size);
size += marker_size;
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
if (needs_cr)
dest[size++] = '\r';
dest[size++] = '\n';
}
/* Postimage from side #2 */
size += xdl_recs_copy(xe2, m->i2, m->chg2, needs_cr, 1,
dest ? dest + size : NULL);
if (!dest) {
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
size += marker_size + 1 + needs_cr + marker2_size;
} else {
memset(dest + size, '>', marker_size);
size += marker_size;
if (marker2_size) {
dest[size] = ' ';
memcpy(dest + size + 1, name2, marker2_size - 1);
size += marker2_size;
}
merge-file: let conflict markers match end-of-line style of the context When merging files with CR/LF line endings, the conflict markers should match those, lest the output file has mixed line endings. This is particularly of interest on Windows, where some editors get *really* confused by mixed line endings. The original version of this patch by Beat Bolli respected core.eol, and a subsequent improvement by this developer also respected gitattributes. This approach was suboptimal, though: `git merge-file` was invented as a drop-in replacement for GNU merge and as such has no problem operating outside of any repository at all! Another problem with the original approach was pointed out by Junio Hamano: legacy repositories might have their text files committed using CR/LF line endings (and core.eol and the gitattributes would give us a false impression there). Therefore, the much superior approach is to simply match the context's line endings, if any. We actually do not have to look at the *entire* context at all: if the files are all LF-only, or if they all have CR/LF line endings, it is sufficient to look at just a *single* line to match that style. And if the line endings are mixed anyway, it is *still* okay to imitate just a single line's eol: we will just add to the pile of mixed line endings, and there is nothing we can do about that. So what we do is: we look at the line preceding the conflict, falling back to the line preceding that in case it was the last line and had no line ending, falling back to the first line, first in the first post-image, then the second post-image, and finally the pre-image. If we find consistent CR/LF (or undecided) end-of-line style, we match that, otherwise we use LF-only line endings for the conflict markers. Note that while it is true that there have to be at least two lines we can look at (otherwise there would be no conflict), the same is not true for line *endings*: the three files in question could all consist of a single line without any line ending, each. In this case we fall back to using LF-only. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-01-27 19:37:36 +03:00
if (needs_cr)
dest[size++] = '\r';
dest[size++] = '\n';
}
return size;
}
static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
xdfenv_t *xe2, const char *name2,
const char *ancestor_name,
int favor,
xdmerge_t *m, char *dest, int style,
int marker_size)
{
int size, i;
for (size = i = 0; m; m = m->next) {
if (favor && !m->mode)
m->mode = favor;
if (m->mode == 0)
size = fill_conflict_hunk(xe1, name1, xe2, name2,
ancestor_name,
size, i, style, m, dest,
marker_size);
else if (m->mode & 3) {
/* Before conflicting part */
size += xdl_recs_copy(xe1, i, m->i1 - i, 0, 0,
dest ? dest + size : NULL);
/* Postimage from side #1 */
if (m->mode & 1) {
int needs_cr = is_cr_needed(xe1, xe2, m);
size += xdl_recs_copy(xe1, m->i1, m->chg1, needs_cr, (m->mode & 2),
dest ? dest + size : NULL);
}
/* Postimage from side #2 */
if (m->mode & 2)
size += xdl_recs_copy(xe2, m->i2, m->chg2, 0, 0,
dest ? dest + size : NULL);
} else
continue;
i = m->i1 + m->chg1;
}
size += xdl_recs_copy(xe1, i, xe1->xdf2.nrec - i, 0, 0,
dest ? dest + size : NULL);
return size;
}
/*
* Sometimes, changes are not quite identical, but differ in only a few
* lines. Try hard to show only these few lines as conflicting.
*/
static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
xpparam_t const *xpp)
{
for (; m; m = m->next) {
mmfile_t t1, t2;
xdfenv_t xe;
xdchange_t *xscr, *x;
int i1 = m->i1, i2 = m->i2;
/* let's handle just the conflicts */
if (m->mode)
continue;
/* no sense refining a conflict when one side is empty */
if (m->chg1 == 0 || m->chg2 == 0)
continue;
/*
* This probably does not work outside git, since
* we have a very simple mmfile structure.
*/
t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
+ xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
+ xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
return -1;
if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
xdl_build_script(&xe, &xscr) < 0) {
xdl_free_env(&xe);
return -1;
}
if (!xscr) {
/* If this happens, the changes are identical. */
xdl_free_env(&xe);
m->mode = 4;
continue;
}
x = xscr;
m->i1 = xscr->i1 + i1;
m->chg1 = xscr->chg1;
m->i2 = xscr->i2 + i2;
m->chg2 = xscr->chg2;
while (xscr->next) {
xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
if (!m2) {
xdl_free_env(&xe);
xdl_free_script(x);
return -1;
}
xscr = xscr->next;
m2->next = m->next;
m->next = m2;
m = m2;
m->mode = 0;
m->i1 = xscr->i1 + i1;
m->chg1 = xscr->chg1;
m->i2 = xscr->i2 + i2;
m->chg2 = xscr->chg2;
}
xdl_free_env(&xe);
xdl_free_script(x);
}
return 0;
}
static int line_contains_alnum(const char *ptr, long size)
{
while (size--)
if (isalnum((unsigned char)*(ptr++)))
return 1;
return 0;
}
static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
{
for (; chg; chg--, i++)
if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
xe->xdf2.recs[i]->size))
return 1;
return 0;
}
/*
* This function merges m and m->next, marking everything between those hunks
* as conflicting, too.
*/
static void xdl_merge_two_conflicts(xdmerge_t *m)
{
xdmerge_t *next_m = m->next;
m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
m->next = next_m->next;
free(next_m);
}
/*
* If there are less than 3 non-conflicting lines between conflicts,
* it appears simpler -- because it takes up less (or as many) lines --
* if the lines are moved into the conflicts.
*/
static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
int simplify_if_no_alnum)
{
int result = 0;
if (!m)
return result;
for (;;) {
xdmerge_t *next_m = m->next;
int begin, end;
if (!next_m)
return result;
begin = m->i1 + m->chg1;
end = next_m->i1;
if (m->mode != 0 || next_m->mode != 0 ||
(end - begin > 3 &&
(!simplify_if_no_alnum ||
lines_contain_alnum(xe1, begin, end - begin)))) {
m = next_m;
} else {
result++;
xdl_merge_two_conflicts(m);
}
}
}
/*
* level == 0: mark all overlapping changes as conflict
* level == 1: mark overlapping changes as conflict only if not identical
* level == 2: analyze non-identical changes for minimal conflict set
* level == 3: analyze non-identical changes for minimal conflict set, but
* treat hunks not containing any letter or number as conflicting
*
* returns < 0 on error, == 0 for no conflicts, else number of conflicts
*/
static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1,
xdfenv_t *xe2, xdchange_t *xscr2,
xmparam_t const *xmp, mmbuffer_t *result)
{
xdmerge_t *changes, *c;
xpparam_t const *xpp = &xmp->xpp;
const char *const ancestor_name = xmp->ancestor;
const char *const name1 = xmp->file1;
const char *const name2 = xmp->file2;
int i0, i1, i2, chg0, chg1, chg2;
int level = xmp->level;
int style = xmp->style;
int favor = xmp->favor;
xmerge.c: "diff3 -m" style clips merge reduction level to EAGER or less When showing a conflicting merge result, and "--diff3 -m" style is asked for, this patch makes sure that the merge reduction level does not exceed XDL_MERGE_EAGER. This is because "diff3 -m" style output would not make sense for anything more aggressive than XDL_MERGE_EAGER, because of the way how the merge reduction works. "git merge-file" no longer has to force MERGE_EAGER when "--diff3" is asked for because of this change. Suppose a common ancestor (shared preimage) is modified to postimage #1 and #2 (each letter represents one line): ##### postimage#1: 1234ABCDE789 | / | / preimage: 123456789 | \ postimage#2: 1234AXYE789 #### XDL_MERGE_MINIMAL and XDL_MERGE_EAGER would: (1) find the s/56/ABCDE/ done on one side and s/56/AXYE/ done on the other side, (2) notice that they touch an overlapping area, and (3) mark it as a conflict, "ABCDE vs AXYE". The difference between the two algorithms is that EAGER drops the hunk altogether if the postimages match (i.e. both sides modified the same way), while MINIMAL keeps it. There is no other operation performed to the hunk. As the result, lines marked with "#" in the above picure will be in the RCS merge style output like this (letters <, = and > represent conflict marker lines): output: 1234<ABCDE=AXYE>789 ; with MINIMAL/EAGER The part from the preimage that corresponds to these conflicting changes is "56", which is what "diff3 -m" style output adds to it: output: 1234<ABCDE|56=AXYE>789 ; in "diff3 -m" style Now, XDL_MERGE_ZEALOUS looks at the differences between the changes two postimages made in order to reduce the number of lines in the conflicting regions. It notices that both sides start their new contents with "A", and excludes it from the output (it also excludes "E" for the same reason). The conflict that used to be "ABCDE vs AXYE" is now "BCD vs XY": output: 1234A<BCD=XY>E789 ; with ZEALOUS There could even be matching parts between two postimages in the middle. Instead of one side rewriting the shared "56" to "ABCDE" and the other side to "AXYE", imagine the case where the postimages are "ABCDE" and "AXCYE", in which case instead of having one conflicted hunk "BCD vs XY", you would have two conflicting hunks "B vs X" and "D vs Y". In either case, once you reduce "ABCDE vs AXYE" to "BCD vs XY" (or "ABCDE vs AXCYE" to "B vs X" and "D vs Y"), there is no part from the preimage that corresponds to the conflicting change made in both postimages anymore. In other words, conflict reduced by ZEALOUS algorithm cannot be expressed in "diff3 -m" style. Representing the last illustration like this is misleading to say the least: output: 1234A<BCD|56=XY>E789 ; broken "diff3 -m" style because the preimage was not ...4A56E... to begin with. "A" and "E" are common only between the postimages. Even worse, once a single conflicting hunk is split into multiple ones (recall the example of breaking "ABCDE vs AXCYE" to "B vs X" and "D vs Y"), there is no sane way to distribute the preimage text across split conflicting hunks. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-08-29 19:22:55 +04:00
if (style == XDL_MERGE_DIFF3) {
/*
* "diff3 -m" output does not make sense for anything
* more aggressive than XDL_MERGE_EAGER.
*/
if (XDL_MERGE_EAGER < level)
level = XDL_MERGE_EAGER;
}
c = changes = NULL;
while (xscr1 && xscr2) {
if (!changes)
changes = c;
if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
i0 = xscr1->i1;
i1 = xscr1->i2;
i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
chg0 = xscr1->chg1;
chg1 = xscr1->chg2;
chg2 = xscr1->chg1;
if (xdl_append_merge(&c, 1,
i0, chg0, i1, chg1, i2, chg2)) {
xdl_cleanup_merge(changes);
return -1;
}
xscr1 = xscr1->next;
continue;
}
if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
i0 = xscr2->i1;
i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
i2 = xscr2->i2;
chg0 = xscr2->chg1;
chg1 = xscr2->chg1;
chg2 = xscr2->chg2;
if (xdl_append_merge(&c, 2,
i0, chg0, i1, chg1, i2, chg2)) {
xdl_cleanup_merge(changes);
return -1;
}
xscr2 = xscr2->next;
continue;
}
if (level == XDL_MERGE_MINIMAL || xscr1->i1 != xscr2->i1 ||
xscr1->chg1 != xscr2->chg1 ||
xscr1->chg2 != xscr2->chg2 ||
xdl_merge_cmp_lines(xe1, xscr1->i2,
xe2, xscr2->i2,
xscr1->chg2, xpp->flags)) {
/* conflict */
int off = xscr1->i1 - xscr2->i1;
int ffo = off + xscr1->chg1 - xscr2->chg1;
i0 = xscr1->i1;
i1 = xscr1->i2;
i2 = xscr2->i2;
if (off > 0) {
i0 -= off;
i1 -= off;
}
else
i2 += off;
chg0 = xscr1->i1 + xscr1->chg1 - i0;
chg1 = xscr1->i2 + xscr1->chg2 - i1;
chg2 = xscr2->i2 + xscr2->chg2 - i2;
if (ffo < 0) {
chg0 -= ffo;
chg1 -= ffo;
} else
chg2 += ffo;
if (xdl_append_merge(&c, 0,
i0, chg0, i1, chg1, i2, chg2)) {
xdl_cleanup_merge(changes);
return -1;
}
}
i1 = xscr1->i1 + xscr1->chg1;
i2 = xscr2->i1 + xscr2->chg1;
if (i1 >= i2)
xscr2 = xscr2->next;
if (i2 >= i1)
xscr1 = xscr1->next;
}
while (xscr1) {
if (!changes)
changes = c;
i0 = xscr1->i1;
i1 = xscr1->i2;
i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
chg0 = xscr1->chg1;
chg1 = xscr1->chg2;
chg2 = xscr1->chg1;
if (xdl_append_merge(&c, 1,
i0, chg0, i1, chg1, i2, chg2)) {
xdl_cleanup_merge(changes);
return -1;
}
xscr1 = xscr1->next;
}
while (xscr2) {
if (!changes)
changes = c;
i0 = xscr2->i1;
i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
i2 = xscr2->i2;
chg0 = xscr2->chg1;
chg1 = xscr2->chg1;
chg2 = xscr2->chg2;
if (xdl_append_merge(&c, 2,
i0, chg0, i1, chg1, i2, chg2)) {
xdl_cleanup_merge(changes);
return -1;
}
xscr2 = xscr2->next;
}
if (!changes)
changes = c;
/* refine conflicts */
if (XDL_MERGE_ZEALOUS <= level &&
(xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
xdl_simplify_non_conflicts(xe1, changes,
XDL_MERGE_ZEALOUS < level) < 0)) {
xdl_cleanup_merge(changes);
return -1;
}
/* output */
if (result) {
int marker_size = xmp->marker_size;
int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2,
ancestor_name,
favor, changes, NULL, style,
marker_size);
result->ptr = xdl_malloc(size);
if (!result->ptr) {
xdl_cleanup_merge(changes);
return -1;
}
result->size = size;
xdl_fill_merge_buffer(xe1, name1, xe2, name2,
ancestor_name, favor, changes,
result->ptr, style, marker_size);
}
return xdl_cleanup_merge(changes);
}
int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
xmparam_t const *xmp, mmbuffer_t *result)
{
xdchange_t *xscr1, *xscr2;
xdfenv_t xe1, xe2;
int status;
xpparam_t const *xpp = &xmp->xpp;
result->ptr = NULL;
result->size = 0;
if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0) {
return -1;
}
if (xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
xdl_free_env(&xe1);
return -1;
}
if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
xdl_build_script(&xe1, &xscr1) < 0) {
xdl_free_env(&xe1);
return -1;
}
if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
xdl_build_script(&xe2, &xscr2) < 0) {
xdl_free_script(xscr1);
xdl_free_env(&xe1);
xdl_free_env(&xe2);
return -1;
}
status = 0;
if (!xscr1) {
result->ptr = xdl_malloc(mf2->size);
memcpy(result->ptr, mf2->ptr, mf2->size);
result->size = mf2->size;
} else if (!xscr2) {
result->ptr = xdl_malloc(mf1->size);
memcpy(result->ptr, mf1->ptr, mf1->size);
result->size = mf1->size;
} else {
status = xdl_do_merge(&xe1, xscr1,
&xe2, xscr2,
xmp, result);
}
xdl_free_script(xscr1);
xdl_free_script(xscr2);
xdl_free_env(&xe1);
xdl_free_env(&xe2);
return status;
}