Merge branch 'maint'
[gitweb.git] / combine-diff.c
index 3b219a01a1003e5ef3cbb61d10c88f176bcd8825..7693884fdb7e43d0aecd77ad1c71531181d7ceee 100644 (file)
@@ -1,35 +1,25 @@
 #include "cache.h"
 #include "commit.h"
+#include "blob.h"
 #include "diff.h"
 #include "diffcore.h"
 #include "quote.h"
 
-struct path_list {
-       struct path_list *next;
-       int len;
-       char *path;
-       unsigned char sha1[20];
-       unsigned char parent_sha1[FLEX_ARRAY][20];
-};
-
 static int uninteresting(struct diff_filepair *p)
 {
        if (diff_unmodified_pair(p))
                return 1;
-       if (!S_ISREG(p->one->mode) || !S_ISREG(p->two->mode))
-               return 1;
        return 0;
 }
 
-static struct path_list *intersect_paths(struct path_list *curr,
-                                        int n, int num_parent)
+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 path_list *p;
+       struct combine_diff_path *p;
        int i;
 
        if (!n) {
-               struct path_list *list = NULL, **tail = &list;
+               struct combine_diff_path *list = NULL, **tail = &list;
                for (i = 0; i < q->nr; i++) {
                        int len;
                        const char *path;
@@ -37,15 +27,20 @@ static struct path_list *intersect_paths(struct path_list *curr,
                                continue;
                        path = q->queue[i]->two->path;
                        len = strlen(path);
-
-                       p = xmalloc(sizeof(*p) + len + 1 + num_parent * 20);
-                       p->path = (char*) &(p->parent_sha1[num_parent][0]);
+                       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);
-                       memcpy(p->parent_sha1[n], q->queue[i]->one->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;
+                       p->parent[n].status = q->queue[i]->status;
                        *tail = p;
                        tail = &p->next;
                }
@@ -66,8 +61,10 @@ static struct path_list *intersect_paths(struct path_list *curr,
                        len = strlen(path);
                        if (len == p->len && !memcmp(path, p->path, len)) {
                                found = 1;
-                               memcpy(p->parent_sha1[n],
+                               memcpy(p->parent[n].sha1,
                                       q->queue[i]->one->sha1, 20);
+                               p->parent[n].mode = q->queue[i]->one->mode;
+                               p->parent[n].status = q->queue[i]->status;
                                break;
                        }
                }
@@ -77,6 +74,7 @@ static struct path_list *intersect_paths(struct path_list *curr,
        return curr;
 }
 
+/* Lines lost from parent */
 struct lline {
        struct lline *next;
        int len;
@@ -84,11 +82,17 @@ struct lline {
        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)
@@ -101,7 +105,7 @@ static char *grab_blob(const unsigned char *sha1, unsigned long *size)
                return xcalloc(1, 1);
        }
        blob = read_sha1_file(sha1, type, size);
-       if (strcmp(type, "blob"))
+       if (strcmp(type, blob_type))
                die("object '%s' is not a blob!", sha1_to_hex(sha1));
        return blob;
 }
@@ -213,22 +217,25 @@ static void append_lost(struct sline *sline, int n, const char *line)
 }
 
 static void combine_diff(const unsigned char *parent, const char *ourtmp,
-                        struct sline *sline, int cnt, int n)
+                        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;
-       unsigned long pmask = ~(1UL << n);
+       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)
-               return;
+               die("cannot spawn %s", cmd);
 
        lno = 1;
        while (fgets(line, sizeof(line), in) != NULL) {
@@ -238,29 +245,64 @@ static void combine_diff(const unsigned char *parent, const char *ourtmp,
                                              &ob, &on, &nb, &nn))
                                break;
                        lno = nb;
-                       if (!nb) {
+                       if (!nb)
                                /* @@ -1,2 +0,0 @@ to remove the
                                 * first two lines...
                                 */
                                nb = 1;
-                       }
-                       lost_bucket = &sline[nb-1]; /* sline is 0 based */
+                       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;
+                       continue; /* not in any hunk yet */
                switch (line[0]) {
                case '-':
                        append_lost(lost_bucket, n, line+1);
                        break;
                case '+':
-                       sline[lno-1].flag &= pmask;
+                       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;
@@ -268,59 +310,111 @@ static char combine_marker = '@';
 
 static int interesting(struct sline *sline, unsigned long all_mask)
 {
-       return ((sline->flag & all_mask) != all_mask || sline->lost_head);
+       /* 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 line_common_diff(struct sline *sline, unsigned long all_mask)
+static unsigned long adjust_hunk_tail(struct sline *sline,
+                                     unsigned long all_mask,
+                                     unsigned long hunk_begin,
+                                     unsigned long i)
 {
-       /*
-        * Look at the line and see from which parents we have the
-        * same difference.
+       /* 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;
+}
 
-       /* Lower bits of sline->flag records if the parent had this
-        * line, so XOR with all_mask gives us on-bits for parents we
-        * have differences with.
+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.
         */
-       unsigned long common_adds = (sline->flag ^ all_mask) & all_mask;
-       unsigned long common_removes = all_mask;
+       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;
 
-       /* If all the parents have this line, that also counts as
-        * having the same difference.
+       /* 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.
         */
-       if (!common_adds)
-               common_adds = all_mask;
+       i = find_next(sline, mark, 0, cnt, 0);
+       if (cnt <= i)
+               return 0;
 
-       if (sline->lost_head) {
-               /* Lost head list records the lines removed from
-                * the parents, and parent_map records from which
-                * parent the line was removed.
+       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?
                 */
-               struct lline *ll;
-               for (ll = sline->lost_head; ll; ll = ll->next) {
-                       common_removes &= ll->parent_map;
+               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;
                }
-       }
-       return common_adds & common_removes;
-}
 
-static unsigned long line_all_diff(struct sline *sline, unsigned long all_mask)
-{
-       /*
-        * Look at the line and see from which parents we have some difference.
-        */
-       unsigned long different = (sline->flag ^ all_mask) & all_mask;
-       if (sline->lost_head) {
-               /* Lost head list records the lines removed from
-                * the parents, and parent_map records from which
-                * parent the line was removed.
+               /* j is the first uninteresting line and there is
+                * no overlap beyond it within context lines.  Paint
+                * the trailing edge a bit.
                 */
-               struct lline *ll;
-               for (ll = sline->lost_head; ll; ll = ll->next) {
-                       different |= ll->parent_map;
-               }
+               i = k;
+               k = (j + context < cnt) ? j + context : cnt;
+               while (j < k)
+                       sline[j++].flag |= mark;
        }
-       return different;
+       return 1;
 }
 
 static int make_hunks(struct sline *sline, unsigned long cnt,
@@ -331,77 +425,129 @@ static int make_hunks(struct sline *sline, unsigned long cnt,
        unsigned long i;
        int has_interesting = 0;
 
-       i = 0;
-       while (i < cnt) {
-               if (interesting(&sline[i], all_mask)) {
-                       unsigned long j = (context < i) ? i - context : 0;
-                       while (j <= i)
-                               sline[j++].flag |= mark;
-                       while (++i < cnt) {
-                               if (!interesting(&sline[i], all_mask))
-                                       break;
-                               sline[i].flag |= mark;
-                       }
-                       j = (i + context < cnt) ? i + context : cnt;
-                       while (i < j)
-                               sline[i++].flag |= mark;
-                       has_interesting = 1;
-                       continue;
-               }
-               i++;
+       for (i = 0; i < cnt; i++) {
+               if (interesting(&sline[i], all_mask))
+                       sline[i].flag |= mark;
+               else
+                       sline[i].flag &= ~mark;
        }
        if (!dense)
-               return has_interesting;
+               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.
         */
-       has_interesting = 0;
        i = 0;
        while (i < cnt) {
-               int j, hunk_end, same, diff;
-               unsigned long same_diff, all_diff;
+               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 */
-               for (hunk_end = i + 1; hunk_end < cnt; hunk_end++)
-                       if (!(sline[hunk_end].flag & mark))
-                               break;
-               /* [i..hunk_end) are interesting.  Now does it have
-                * the same change with all but one parent?
-                */
-               same_diff = all_mask;
-               all_diff = 0;
-               for (j = i; j < hunk_end; j++) {
-                       same_diff &= line_common_diff(sline + j, all_mask);
-                       all_diff |= line_all_diff(sline + j, all_mask);
+               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;
+                       }
                }
-               diff = same = 0;
-               for (j = 0; j < num_parent; j++) {
-                       if (same_diff & (1UL<<j))
-                               same++;
-                       if (all_diff & (1UL<<j))
-                               diff++;
+               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 ((num_parent - 1 <= same) || (diff == 1)) {
+
+               if (!has_interesting && same_diff != all_mask) {
                        /* This hunk is not that interesting after all */
-                       for (j = i; j < hunk_end; j++)
+                       for (j = hunk_begin; j < hunk_end; j++)
                                sline[j].flag &= ~mark;
                }
-               else
-                       has_interesting = 1;
                i = hunk_end;
        }
+
+       has_interesting = give_context(sline, cnt, num_parent);
        return has_interesting;
 }
 
-static void dump_sline(struct sline *sline, int cnt, int num_parent)
+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;
-       int lno = 0;
+       unsigned long lno = 0;
+
+       if (!cnt)
+               return; /* result deleted */
 
        while (1) {
                struct sline *sl = &sline[lno];
@@ -414,12 +560,15 @@ static void dump_sline(struct sline *sline, int cnt, int num_parent)
                        if (!(sline[hunk_end].flag & mark))
                                break;
                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
-               printf(" +%d,%d ", lno+1, hunk_end-lno);
+               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) {
@@ -432,75 +581,194 @@ static void dump_sline(struct sline *sline, int cnt, int num_parent)
                                puts(ll->line);
                                ll = ll->next;
                        }
+                       p_mask = 1;
                        for (j = 0; j < num_parent; j++) {
-                               if ((1UL<<j) & sl->flag)
-                                       putchar(' ');
-                               else
+                               if (p_mask & sl->flag)
                                        putchar('+');
+                               else
+                                       putchar(' ');
+                               p_mask <<= 1;
                        }
                        printf("%.*s\n", sl->len, sl->bol);
                }
        }
 }
 
-static int show_combined_diff(struct path_list *elem, int num_parent,
-                             int dense, const char *header, int show_empty)
+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];
+}
+
+static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
+                          int dense, const char *header,
+                          struct diff_options *opt)
 {
        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[TMPPATHLEN];
+       char ourtmp_buf[TMPPATHLEN];
+       char *ourtmp = ourtmp_buf;
+       int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
+       int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
 
        /* Read the result of merge first */
-       result = grab_blob(elem->sha1, &size);
-       write_to_temp_file(ourtmp, result, size);
+       if (!working_tree_file) {
+               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;
+
+                       elem->mode = canon_mode(st.st_mode);
+                       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;
+                       elem->mode = 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 (result[size-1] != '\n')
+       if (size && result[size-1] != '\n')
                cnt++; /* incomplete line */
 
-       sline = xcalloc(cnt, sizeof(*sline));
+       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].lost_tail = &sline[lno].lost_head;
                        sline[lno].len = cp - sline[lno].bol;
-                       sline[lno].flag = (1UL<<num_parent) - 1;
                        lno++;
                        if (lno < cnt)
                                sline[lno].bol = cp + 1;
                }
        }
-       if (result[size-1] != '\n') {
-               sline[cnt-1].lost_tail = &sline[cnt-1].lost_head;
+       if (size && result[size-1] != '\n')
                sline[cnt-1].len = size - (sline[cnt-1].bol - result);
-               sline[cnt-1].flag = (1UL<<num_parent) - 1;
-       }
 
-       for (i = 0; i < num_parent; i++)
-               combine_diff(elem->parent_sha1[i], ourtmp, sline, cnt, i);
+       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 (header && (show_hunks || show_empty)) {
-               shown_header++;
-               puts(header);
-       }
-       if (show_hunks) {
+       if (show_hunks || mode_differs || working_tree_file) {
+               const char *abb;
+
+               if (header) {
+                       shown_header++;
+                       printf("%s%c", header, opt->line_termination);
+               }
                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++) {
+                       abb = find_unique_abbrev(elem->parent[i].sha1,
+                                                abbrev);
+                       printf("%s%s", i ? "," : "", abb);
+               }
+               abb = find_unique_abbrev(elem->sha1, abbrev);
+               printf("..%s\n", abb);
+
+               if (mode_differs) {
+                       int added = !!elem->mode;
+                       for (i = 0; added && i < num_parent; i++)
+                               if (elem->parent[i].status !=
+                                   DIFF_STATUS_ADDED)
+                                       added = 0;
+                       if (added)
+                               printf("new file mode %06o", elem->mode);
+                       else {
+                               if (!elem->mode)
+                                       printf("deleted file ");
+                               printf("mode ");
+                               for (i = 0; i < num_parent; i++) {
+                                       printf("%s%06o", i ? "," : "",
+                                              elem->parent[i].mode);
+                               }
+                               if (elem->mode)
+                                       printf("..%06o", elem->mode);
+                       }
+                       putchar('\n');
+               }
                dump_sline(sline, cnt, num_parent);
        }
-       unlink(ourtmp);
+       if (ourtmp == ourtmp_buf)
+               unlink(ourtmp);
        free(result);
 
        for (i = 0; i < cnt; i++) {
@@ -513,21 +781,105 @@ static int show_combined_diff(struct path_list *elem, int num_parent,
                        }
                }
        }
+       free(sline[0].p_lno);
        free(sline);
        return shown_header;
 }
 
-int diff_tree_combined_merge(const unsigned char *sha1,
-                            const char *header,
-                            int show_empty_merge, int dense)
+#define COLONS "::::::::::::::::::::::::::::::::"
+
+static void show_raw_diff(struct combine_diff_path *p, int num_parent, const char *header, struct diff_options *opt)
+{
+       int i, offset, mod_type = 'A';
+       const char *prefix;
+       int line_termination, inter_name_termination;
+
+       line_termination = opt->line_termination;
+       inter_name_termination = '\t';
+       if (!line_termination)
+               inter_name_termination = 0;
+
+       if (header)
+               printf("%s%c", header, line_termination);
+
+       for (i = 0; i < num_parent; i++) {
+               if (p->parent[i].mode)
+                       mod_type = 'M';
+       }
+       if (!p->mode)
+               mod_type = 'D';
+
+       if (opt->output_format == DIFF_FORMAT_RAW) {
+               offset = strlen(COLONS) - num_parent;
+               if (offset < 0)
+                       offset = 0;
+               prefix = COLONS + offset;
+
+               /* Show the modes */
+               for (i = 0; i < num_parent; i++) {
+                       printf("%s%06o", prefix, p->parent[i].mode);
+                       prefix = " ";
+               }
+               printf("%s%06o", prefix, p->mode);
+
+               /* Show sha1's */
+               for (i = 0; i < num_parent; i++)
+                       printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
+                                                        opt->abbrev));
+               printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
+       }
+
+       if (opt->output_format == DIFF_FORMAT_RAW ||
+           opt->output_format == DIFF_FORMAT_NAME_STATUS) {
+               for (i = 0; i < num_parent; i++)
+                       putchar(p->parent[i].status);
+               putchar(inter_name_termination);
+       }
+
+       if (line_termination) {
+               if (quote_c_style(p->path, NULL, NULL, 0))
+                       quote_c_style(p->path, NULL, stdout, 0);
+               else
+                       printf("%s", p->path);
+               putchar(line_termination);
+       }
+       else {
+               printf("%s%c", p->path, line_termination);
+       }
+}
+
+int show_combined_diff(struct combine_diff_path *p,
+                      int num_parent,
+                      int dense,
+                      const char *header,
+                      struct diff_options *opt)
+{
+       if (!p->len)
+               return 0;
+       switch (opt->output_format) {
+       case DIFF_FORMAT_RAW:
+       case DIFF_FORMAT_NAME_STATUS:
+       case DIFF_FORMAT_NAME:
+               show_raw_diff(p, num_parent, header, opt);
+               return 1;
+
+       default:
+       case DIFF_FORMAT_PATCH:
+               return show_patch_diff(p, num_parent, dense, header, opt);
+       }
+}
+
+const char *diff_tree_combined_merge(const unsigned char *sha1,
+                            const char *header, int dense,
+                            struct diff_options *opt)
 {
        struct commit *commit = lookup_commit(sha1);
        struct diff_options diffopts;
        struct commit_list *parents;
-       struct path_list *p, *paths = NULL;
+       struct combine_diff_path *p, *paths = NULL;
        int num_parent, i, num_paths;
 
-       diff_setup(&diffopts);
+       diffopts = *opt;
        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
        diffopts.recursive = 1;
 
@@ -544,6 +896,7 @@ int diff_tree_combined_merge(const unsigned char *sha1,
                struct commit *parent = parents->item;
                diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
                               &diffopts);
+               diffcore_std(&diffopts);
                paths = intersect_paths(paths, i, num_parent);
                diff_flush(&diffopts);
        }
@@ -553,21 +906,19 @@ int diff_tree_combined_merge(const unsigned char *sha1,
                if (p->len)
                        num_paths++;
        }
-       if (num_paths || show_empty_merge) {
+       if (num_paths) {
                for (p = paths; p; p = p->next) {
-                       if (!p->len)
-                               continue;
-                       if (show_combined_diff(p, num_parent, dense, header,
-                                              show_empty_merge))
+                       if (show_combined_diff(p, num_parent, dense,
+                                              header, opt))
                                header = NULL;
                }
        }
 
        /* Clean things up */
        while (paths) {
-               struct path_list *tmp = paths;
+               struct combine_diff_path *tmp = paths;
                paths = paths->next;
                free(tmp);
        }
-       return 0;
+       return header;
 }