git/combine-diff.c

831 строка
20 KiB
C

#include "cache.h"
#include "commit.h"
#include "diff.h"
#include "diffcore.h"
#include "quote.h"
static int uninteresting(struct diff_filepair *p)
{
if (diff_unmodified_pair(p))
return 1;
return 0;
}
static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
{
struct diff_queue_struct *q = &diff_queued_diff;
struct combine_diff_path *p;
int i;
if (!n) {
struct combine_diff_path *list = NULL, **tail = &list;
for (i = 0; i < q->nr; i++) {
int len;
const char *path;
if (uninteresting(q->queue[i]))
continue;
path = q->queue[i]->two->path;
len = strlen(path);
p = xmalloc(combine_diff_path_size(num_parent, len));
p->path = (char*) &(p->parent[num_parent]);
memcpy(p->path, path, len);
p->path[len] = 0;
p->len = len;
p->next = NULL;
memset(p->parent, 0,
sizeof(p->parent[0]) * num_parent);
memcpy(p->sha1, q->queue[i]->two->sha1, 20);
p->mode = q->queue[i]->two->mode;
memcpy(p->parent[n].sha1, q->queue[i]->one->sha1, 20);
p->parent[n].mode = q->queue[i]->one->mode;
*tail = p;
tail = &p->next;
}
return list;
}
for (p = curr; p; p = p->next) {
int found = 0;
if (!p->len)
continue;
for (i = 0; i < q->nr; i++) {
const char *path;
int len;
if (uninteresting(q->queue[i]))
continue;
path = q->queue[i]->two->path;
len = strlen(path);
if (len == p->len && !memcmp(path, p->path, len)) {
found = 1;
memcpy(p->parent[n].sha1,
q->queue[i]->one->sha1, 20);
p->parent[n].mode = q->queue[i]->one->mode;
break;
}
}
if (!found)
p->len = 0;
}
return curr;
}
/* Lines lost from parent */
struct lline {
struct lline *next;
int len;
unsigned long parent_map;
char line[FLEX_ARRAY];
};
/* Lines surviving in the merge result */
struct sline {
struct lline *lost_head, **lost_tail;
char *bol;
int len;
/* bit 0 up to (N-1) are on if the parent has this line (i.e.
* we did not change it).
* bit N is used for "interesting" lines, including context.
*/
unsigned long flag;
unsigned long *p_lno;
};
static char *grab_blob(const unsigned char *sha1, unsigned long *size)
{
char *blob;
char type[20];
if (!memcmp(sha1, null_sha1, 20)) {
/* deleted blob */
*size = 0;
return xcalloc(1, 1);
}
blob = read_sha1_file(sha1, type, size);
if (strcmp(type, "blob"))
die("object '%s' is not a blob!", sha1_to_hex(sha1));
return blob;
}
#define TMPPATHLEN 50
#define MAXLINELEN 10240
static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
{
int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
if (fd < 0)
die("unable to create temp-file");
if (write(fd, blob, size) != size)
die("unable to write temp-file");
close(fd);
}
static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
{
unsigned long size;
void *blob;
blob = grab_blob(sha1, &size);
write_to_temp_file(tmpfile, blob, size);
free(blob);
}
static int parse_num(char **cp_p, unsigned int *num_p)
{
char *cp = *cp_p;
unsigned int num = 0;
int read_some;
while ('0' <= *cp && *cp <= '9')
num = num * 10 + *cp++ - '0';
if (!(read_some = cp - *cp_p))
return -1;
*cp_p = cp;
*num_p = num;
return 0;
}
static int parse_hunk_header(char *line, int len,
unsigned int *ob, unsigned int *on,
unsigned int *nb, unsigned int *nn)
{
char *cp;
cp = line + 4;
if (parse_num(&cp, ob)) {
bad_line:
return error("malformed diff output: %s", line);
}
if (*cp == ',') {
cp++;
if (parse_num(&cp, on))
goto bad_line;
}
else
*on = 1;
if (*cp++ != ' ' || *cp++ != '+')
goto bad_line;
if (parse_num(&cp, nb))
goto bad_line;
if (*cp == ',') {
cp++;
if (parse_num(&cp, nn))
goto bad_line;
}
else
*nn = 1;
return -!!memcmp(cp, " @@", 3);
}
static void append_lost(struct sline *sline, int n, const char *line)
{
struct lline *lline;
int len = strlen(line);
unsigned long this_mask = (1UL<<n);
if (line[len-1] == '\n')
len--;
/* Check to see if we can squash things */
if (sline->lost_head) {
struct lline *last_one = NULL;
/* We cannot squash it with earlier one */
for (lline = sline->lost_head;
lline;
lline = lline->next)
if (lline->parent_map & this_mask)
last_one = lline;
lline = last_one ? last_one->next : sline->lost_head;
while (lline) {
if (lline->len == len &&
!memcmp(lline->line, line, len)) {
lline->parent_map |= this_mask;
return;
}
lline = lline->next;
}
}
lline = xmalloc(sizeof(*lline) + len + 1);
lline->len = len;
lline->next = NULL;
lline->parent_map = this_mask;
memcpy(lline->line, line, len);
lline->line[len] = 0;
*sline->lost_tail = lline;
sline->lost_tail = &lline->next;
}
static void combine_diff(const unsigned char *parent, const char *ourtmp,
struct sline *sline, int cnt, int n, int num_parent)
{
FILE *in;
char parent_tmp[TMPPATHLEN];
char cmd[TMPPATHLEN * 2 + 1024];
char line[MAXLINELEN];
unsigned int lno, ob, on, nb, nn, p_lno;
unsigned long nmask = (1UL << n);
struct sline *lost_bucket = NULL;
if (!cnt)
return; /* result deleted */
write_temp_blob(parent_tmp, parent);
sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
parent_tmp, ourtmp);
in = popen(cmd, "r");
if (!in)
die("cannot spawn %s", cmd);
lno = 1;
while (fgets(line, sizeof(line), in) != NULL) {
int len = strlen(line);
if (5 < len && !memcmp("@@ -", line, 4)) {
if (parse_hunk_header(line, len,
&ob, &on, &nb, &nn))
break;
lno = nb;
if (!nb)
/* @@ -1,2 +0,0 @@ to remove the
* first two lines...
*/
nb = 1;
if (nn == 0)
/* @@ -X,Y +N,0 @@ removed Y lines
* that would have come *after* line N
* in the result. Our lost buckets hang
* to the line after the removed lines,
*/
lost_bucket = &sline[nb];
else
lost_bucket = &sline[nb-1];
if (!sline[nb-1].p_lno)
sline[nb-1].p_lno =
xcalloc(num_parent,
sizeof(unsigned long));
sline[nb-1].p_lno[n] = ob;
continue;
}
if (!lost_bucket)
continue; /* not in any hunk yet */
switch (line[0]) {
case '-':
append_lost(lost_bucket, n, line+1);
break;
case '+':
sline[lno-1].flag |= nmask;
lno++;
break;
}
}
fclose(in);
unlink(parent_tmp);
/* Assign line numbers for this parent.
*
* sline[lno].p_lno[n] records the first line number
* (counting from 1) for parent N if the final hunk display
* started by showing sline[lno] (possibly showing the lost
* lines attached to it first).
*/
for (lno = 0, p_lno = 1; lno < cnt; lno++) {
struct lline *ll;
sline[lno].p_lno[n] = p_lno;
/* How many lines would this sline advance the p_lno? */
ll = sline[lno].lost_head;
while (ll) {
if (ll->parent_map & nmask)
p_lno++; /* '-' means parent had it */
ll = ll->next;
}
if (!(sline[lno].flag & nmask))
p_lno++; /* no '+' means parent had it */
}
sline[lno].p_lno[n] = p_lno; /* trailer */
}
static unsigned long context = 3;
static char combine_marker = '@';
static int interesting(struct sline *sline, unsigned long all_mask)
{
/* If some parents lost lines here, or if we have added to
* some parent, it is interesting.
*/
return ((sline->flag & all_mask) || sline->lost_head);
}
static unsigned long adjust_hunk_tail(struct sline *sline,
unsigned long all_mask,
unsigned long hunk_begin,
unsigned long i)
{
/* i points at the first uninteresting line. If the last line
* of the hunk was interesting only because it has some
* deletion, then it is not all that interesting for the
* purpose of giving trailing context lines. This is because
* we output '-' line and then unmodified sline[i-1] itself in
* that case which gives us one extra context line.
*/
if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
i--;
return i;
}
static unsigned long find_next(struct sline *sline,
unsigned long mark,
unsigned long i,
unsigned long cnt,
int uninteresting)
{
/* We have examined up to i-1 and are about to look at i.
* Find next interesting or uninteresting line. Here,
* "interesting" does not mean interesting(), but marked by
* the give_context() function below (i.e. it includes context
* lines that are not interesting to interesting() function
* that are surrounded by interesting() ones.
*/
while (i < cnt)
if (uninteresting
? !(sline[i].flag & mark)
: (sline[i].flag & mark))
return i;
else
i++;
return cnt;
}
static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
{
unsigned long all_mask = (1UL<<num_parent) - 1;
unsigned long mark = (1UL<<num_parent);
unsigned long i;
/* Two groups of interesting lines may have a short gap of
* unintersting lines. Connect such groups to give them a
* bit of context.
*
* We first start from what the interesting() function says,
* and mark them with "mark", and paint context lines with the
* mark. So interesting() would still say false for such context
* lines but they are treated as "interesting" in the end.
*/
i = find_next(sline, mark, 0, cnt, 0);
if (cnt <= i)
return 0;
while (i < cnt) {
unsigned long j = (context < i) ? (i - context) : 0;
unsigned long k;
/* Paint a few lines before the first interesting line. */
while (j < i)
sline[j++].flag |= mark;
again:
/* we know up to i is to be included. where does the
* next uninteresting one start?
*/
j = find_next(sline, mark, i, cnt, 1);
if (cnt <= j)
break; /* the rest are all interesting */
/* lookahead context lines */
k = find_next(sline, mark, j, cnt, 0);
j = adjust_hunk_tail(sline, all_mask, i, j);
if (k < j + context) {
/* k is interesting and [j,k) are not, but
* paint them interesting because the gap is small.
*/
while (j < k)
sline[j++].flag |= mark;
i = k;
goto again;
}
/* j is the first uninteresting line and there is
* no overlap beyond it within context lines. Paint
* the trailing edge a bit.
*/
i = k;
k = (j + context < cnt) ? j + context : cnt;
while (j < k)
sline[j++].flag |= mark;
}
return 1;
}
static int make_hunks(struct sline *sline, unsigned long cnt,
int num_parent, int dense)
{
unsigned long all_mask = (1UL<<num_parent) - 1;
unsigned long mark = (1UL<<num_parent);
unsigned long i;
int has_interesting = 0;
for (i = 0; i < cnt; i++) {
if (interesting(&sline[i], all_mask))
sline[i].flag |= mark;
else
sline[i].flag &= ~mark;
}
if (!dense)
return give_context(sline, cnt, num_parent);
/* Look at each hunk, and if we have changes from only one
* parent, or the changes are the same from all but one
* parent, mark that uninteresting.
*/
i = 0;
while (i < cnt) {
unsigned long j, hunk_begin, hunk_end;
unsigned long same_diff;
while (i < cnt && !(sline[i].flag & mark))
i++;
if (cnt <= i)
break; /* No more interesting hunks */
hunk_begin = i;
for (j = i + 1; j < cnt; j++) {
if (!(sline[j].flag & mark)) {
/* Look beyond the end to see if there
* is an interesting line after this
* hunk within context span.
*/
unsigned long la; /* lookahead */
int contin = 0;
la = adjust_hunk_tail(sline, all_mask,
hunk_begin, j);
la = (la + context < cnt) ?
(la + context) : cnt;
while (j <= --la) {
if (sline[la].flag & mark) {
contin = 1;
break;
}
}
if (!contin)
break;
j = la;
}
}
hunk_end = j;
/* [i..hunk_end) are interesting. Now is it really
* interesting? We check if there are only two versions
* and the result matches one of them. That is, we look
* at:
* (+) line, which records lines added to which parents;
* this line appears in the result.
* (-) line, which records from what parents the line
* was removed; this line does not appear in the result.
* then check the set of parents the result has difference
* from, from all lines. If there are lines that has
* different set of parents that the result has differences
* from, that means we have more than two versions.
*
* Even when we have only two versions, if the result does
* not match any of the parents, the it should be considered
* interesting. In such a case, we would have all '+' line.
* After passing the above "two versions" test, that would
* appear as "the same set of parents" to be "all parents".
*/
same_diff = 0;
has_interesting = 0;
for (j = i; j < hunk_end && !has_interesting; j++) {
unsigned long this_diff = sline[j].flag & all_mask;
struct lline *ll = sline[j].lost_head;
if (this_diff) {
/* This has some changes. Is it the
* same as others?
*/
if (!same_diff)
same_diff = this_diff;
else if (same_diff != this_diff) {
has_interesting = 1;
break;
}
}
while (ll && !has_interesting) {
/* Lost this line from these parents;
* who are they? Are they the same?
*/
this_diff = ll->parent_map;
if (!same_diff)
same_diff = this_diff;
else if (same_diff != this_diff) {
has_interesting = 1;
}
ll = ll->next;
}
}
if (!has_interesting && same_diff != all_mask) {
/* This hunk is not that interesting after all */
for (j = hunk_begin; j < hunk_end; j++)
sline[j].flag &= ~mark;
}
i = hunk_end;
}
has_interesting = give_context(sline, cnt, num_parent);
return has_interesting;
}
static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, unsigned long cnt, int n)
{
l0 = sline[l0].p_lno[n];
l1 = sline[l1].p_lno[n];
printf(" -%lu,%lu", l0, l1-l0);
}
static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent)
{
unsigned long mark = (1UL<<num_parent);
int i;
unsigned long lno = 0;
if (!cnt)
return; /* result deleted */
while (1) {
struct sline *sl = &sline[lno];
int hunk_end;
while (lno < cnt && !(sline[lno].flag & mark))
lno++;
if (cnt <= lno)
break;
for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
if (!(sline[hunk_end].flag & mark))
break;
for (i = 0; i <= num_parent; i++) putchar(combine_marker);
for (i = 0; i < num_parent; i++)
show_parent_lno(sline, lno, hunk_end, cnt, i);
printf(" +%lu,%lu ", lno+1, hunk_end-lno);
for (i = 0; i <= num_parent; i++) putchar(combine_marker);
putchar('\n');
while (lno < hunk_end) {
struct lline *ll;
int j;
unsigned long p_mask;
sl = &sline[lno++];
ll = sl->lost_head;
while (ll) {
for (j = 0; j < num_parent; j++) {
if (ll->parent_map & (1UL<<j))
putchar('-');
else
putchar(' ');
}
puts(ll->line);
ll = ll->next;
}
p_mask = 1;
for (j = 0; j < num_parent; j++) {
if (p_mask & sl->flag)
putchar('+');
else
putchar(' ');
p_mask <<= 1;
}
printf("%.*s\n", sl->len, sl->bol);
}
}
}
static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
int i, int j)
{
/* We have already examined parent j and we know parent i
* and parent j are the same, so reuse the combined result
* of parent j for parent i.
*/
unsigned long lno, imask, jmask;
imask = (1UL<<i);
jmask = (1UL<<j);
for (lno = 0; lno < cnt; lno++) {
struct lline *ll = sline->lost_head;
sline->p_lno[i] = sline->p_lno[j];
while (ll) {
if (ll->parent_map & jmask)
ll->parent_map |= imask;
ll = ll->next;
}
if (sline->flag & jmask)
sline->flag |= imask;
sline++;
}
/* the overall size of the file (sline[cnt]) */
sline->p_lno[i] = sline->p_lno[j];
}
int show_combined_diff(struct combine_diff_path *elem, int num_parent,
int dense, const char *header)
{
unsigned long size, cnt, lno;
char *result, *cp, *ep;
struct sline *sline; /* survived lines */
int mode_differs = 0;
int i, show_hunks, shown_header = 0;
char ourtmp_buf[TMPPATHLEN];
char *ourtmp = ourtmp_buf;
/* Read the result of merge first */
if (memcmp(elem->sha1, null_sha1, 20)) {
result = grab_blob(elem->sha1, &size);
write_to_temp_file(ourtmp, result, size);
}
else {
/* Used by diff-tree to read from the working tree */
struct stat st;
int fd;
ourtmp = elem->path;
if (0 <= (fd = open(ourtmp, O_RDONLY)) &&
!fstat(fd, &st)) {
int len = st.st_size;
int cnt = 0;
size = len;
result = xmalloc(len + 1);
while (cnt < len) {
int done = xread(fd, result+cnt, len-cnt);
if (done == 0)
break;
if (done < 0)
die("read error '%s'", ourtmp);
cnt += done;
}
result[len] = 0;
}
else {
/* deleted file */
size = 0;
result = xmalloc(1);
result[0] = 0;
ourtmp = "/dev/null";
}
if (0 <= fd)
close(fd);
}
for (cnt = 0, cp = result; cp - result < size; cp++) {
if (*cp == '\n')
cnt++;
}
if (size && result[size-1] != '\n')
cnt++; /* incomplete line */
sline = xcalloc(cnt+1, sizeof(*sline));
ep = result;
sline[0].bol = result;
for (lno = 0; lno <= cnt; lno++) {
sline[lno].lost_tail = &sline[lno].lost_head;
sline[lno].flag = 0;
}
for (lno = 0, cp = result; cp - result < size; cp++) {
if (*cp == '\n') {
sline[lno].len = cp - sline[lno].bol;
lno++;
if (lno < cnt)
sline[lno].bol = cp + 1;
}
}
if (size && result[size-1] != '\n')
sline[cnt-1].len = size - (sline[cnt-1].bol - result);
sline[0].p_lno = xcalloc((cnt+1) * num_parent, sizeof(unsigned long));
for (lno = 0; lno < cnt; lno++)
sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
for (i = 0; i < num_parent; i++) {
int j;
for (j = 0; j < i; j++) {
if (!memcmp(elem->parent[i].sha1,
elem->parent[j].sha1, 20)) {
reuse_combine_diff(sline, cnt, i, j);
break;
}
}
if (i <= j)
combine_diff(elem->parent[i].sha1, ourtmp, sline,
cnt, i, num_parent);
if (elem->parent[i].mode != elem->mode)
mode_differs = 1;
}
show_hunks = make_hunks(sline, cnt, num_parent, dense);
if (show_hunks || mode_differs) {
const char *abb;
char null_abb[DEFAULT_ABBREV + 1];
memset(null_abb, '0', DEFAULT_ABBREV);
null_abb[DEFAULT_ABBREV] = 0;
if (header) {
shown_header++;
puts(header);
}
printf("diff --%s ", dense ? "cc" : "combined");
if (quote_c_style(elem->path, NULL, NULL, 0))
quote_c_style(elem->path, NULL, stdout, 0);
else
printf("%s", elem->path);
putchar('\n');
printf("index ");
for (i = 0; i < num_parent; i++) {
if (elem->parent[i].mode != elem->mode)
mode_differs = 1;
if (memcmp(elem->parent[i].sha1, null_sha1, 20))
abb = find_unique_abbrev(elem->parent[i].sha1,
DEFAULT_ABBREV);
else
abb = null_abb;
printf("%s%s", i ? "," : "", abb);
}
if (memcmp(elem->sha1, null_sha1, 20))
abb = find_unique_abbrev(elem->sha1, DEFAULT_ABBREV);
else
abb = null_abb;
printf("..%s\n", abb);
if (mode_differs) {
printf("mode ");
for (i = 0; i < num_parent; i++) {
printf("%s%06o", i ? "," : "",
elem->parent[i].mode);
}
printf("..%06o\n", elem->mode);
}
dump_sline(sline, cnt, num_parent);
}
if (ourtmp == ourtmp_buf)
unlink(ourtmp);
free(result);
for (i = 0; i < cnt; i++) {
if (sline[i].lost_head) {
struct lline *ll = sline[i].lost_head;
while (ll) {
struct lline *tmp = ll;
ll = ll->next;
free(tmp);
}
}
}
free(sline[0].p_lno);
free(sline);
return shown_header;
}
int diff_tree_combined_merge(const unsigned char *sha1,
const char *header, int dense)
{
struct commit *commit = lookup_commit(sha1);
struct diff_options diffopts;
struct commit_list *parents;
struct combine_diff_path *p, *paths = NULL;
int num_parent, i, num_paths;
diff_setup(&diffopts);
diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
diffopts.recursive = 1;
/* count parents */
for (parents = commit->parents, num_parent = 0;
parents;
parents = parents->next, num_parent++)
; /* nothing */
/* find set of paths that everybody touches */
for (parents = commit->parents, i = 0;
parents;
parents = parents->next, i++) {
struct commit *parent = parents->item;
diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
&diffopts);
paths = intersect_paths(paths, i, num_parent);
diff_flush(&diffopts);
}
/* find out surviving paths */
for (num_paths = 0, p = paths; p; p = p->next) {
if (p->len)
num_paths++;
}
if (num_paths) {
for (p = paths; p; p = p->next) {
if (!p->len)
continue;
if (show_combined_diff(p, num_parent, dense, header))
header = NULL;
}
}
/* Clean things up */
while (paths) {
struct combine_diff_path *tmp = paths;
paths = paths->next;
free(tmp);
}
return 0;
}