help: check early if we have a command, if not try a documentation topic

diff --git a/combine-diff.c b/combine-diff.c
index 588c58bc55dfe78998d40a4dcce2a7b6ea6f7f5a..9f80a1c5e3a461afd11966625589684d61187911 100644 (file)
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -84,6 +84,7 @@ struct sline {
        /* 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.
+        * bit (N+1) is used for "do not show deletion before this".
         */
        unsigned long flag;
        unsigned long *p_lno;
@@ -308,6 +309,7 @@ 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 no_pre_delete = (2UL<<num_parent);
        unsigned long i;
 
        /* Two groups of interesting lines may have a short gap of
@@ -329,7 +331,7 @@ static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 
                /* Paint a few lines before the first interesting line. */
                while (j < i)
-                       sline[j++].flag |= mark;
+                       sline[j++].flag |= mark | no_pre_delete;
 
        again:
                /* we know up to i is to be included.  where does the
@@ -502,6 +504,7 @@ static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
                       int use_color)
 {
        unsigned long mark = (1UL<<num_parent);
+       unsigned long no_pre_delete = (2UL<<num_parent);
        int i;
        unsigned long lno = 0;
        const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
@@ -581,7 +584,7 @@ static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
                        int j;
                        unsigned long p_mask;
                        sl = &sline[lno++];
-                       ll = sl->lost_head;
+                       ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
                        while (ll) {
                                fputs(c_old, stdout);
                                for (j = 0; j < num_parent; j++) {