46068 (tweaked) (was: github #57): region_highlight: Add memo= support.

This is useful when multiple plugins add region_highlight entries and
subsequently want to remove only their own entries.  Without this
functionality, recognizing one's region_highlight entries is not trivial
because the 'start' and 'end' offsets are modified by editing of $BUFFER
and the highlight specification may not be unique or distinctive.

The tweaks are as follows:

- Change zfree() to zsfree() per workers/46070.

- Remove the mem.c hunk, as it changed the signature of only one out of
  two alternative definitions of zsfree().  (The definition that hunk
  touched is the one that's not used by default.)

1 files changed, 56 insertions, 6 deletions

diff --git a/Src/Zle/zle_refresh.c b/Src/Zle/zle_refresh.c
index 7b8593dec..d9d9503e2 100644
--- a/Src/Zle/zle_refresh.c
+++ b/Src/Zle/zle_refresh.c
@@ -212,9 +212,9 @@ static zattr default_atr_on, special_atr_on;
 
 /*
  * Array of region highlights, no special termination.
- * The first element (0) always describes the region between
- * point and mark.  Any other elements are set by the user
- * via the parameter region_highlight.
+ * The first N_SPECIAL_HIGHLIGHTS elements describe special uses of
+ * highlighting, documented under N_SPECIAL_HIGHLIGHTS.
+ * Any other elements are set by the user via the parameter region_highlight.
  */
 
 /**/
@@ -414,16 +414,19 @@ get_region_highlight(UNUSED(Param pm))
 	 arrsize--;
 	 rhp++, arrp++) {
 	char digbuf1[DIGBUFSIZE], digbuf2[DIGBUFSIZE];
-	int atrlen = 0, alloclen;
+	int atrlen, alloclen;
+	const char memo_equals[] = "memo=";
 
 	sprintf(digbuf1, "%d", rhp->start);
 	sprintf(digbuf2, "%d", rhp->end);
 
 	atrlen = output_highlight(rhp->atr, NULL);
 	alloclen = atrlen + strlen(digbuf1) + strlen(digbuf2) +
-	    3; /* 2 spaces, 1 0 */
+	    3; /* 2 spaces, 1 terminating NUL */
 	if (rhp->flags & ZRH_PREDISPLAY)
 	    alloclen += 2; /* "P " */
+	if (rhp->memo)
+	    alloclen += 1 /* space */ + strlen(memo_equals) + strlen(rhp->memo);
 	*arrp = (char *)zhalloc(alloclen * sizeof(char));
 	/*
 	 * On input we allow a space after the flags.
@@ -436,6 +439,12 @@ get_region_highlight(UNUSED(Param pm))
 		(rhp->flags & ZRH_PREDISPLAY) ? "P" : "",
 		digbuf1, digbuf2);
 	(void)output_highlight(rhp->atr, *arrp + strlen(*arrp));
+
+	if (rhp->memo) {
+	    strcat(*arrp, " ");
+	    strcat(*arrp, memo_equals);
+	    strcat(*arrp, rhp->memo);
+	}
     }
     *arrp = NULL;
     return retarr;
@@ -460,6 +469,8 @@ set_region_highlight(UNUSED(Param pm), char **aval)
 	/* no null termination, but include special highlighting at start */
 	int newsize = len + N_SPECIAL_HIGHLIGHTS;
 	int diffsize = newsize - n_region_highlights;
+
+	free_region_highlights_memos();
 	region_highlights = (struct region_highlight *)
 	    zrealloc(region_highlights,
 		     sizeof(struct region_highlight) * newsize);
@@ -476,6 +487,7 @@ set_region_highlight(UNUSED(Param pm), char **aval)
 	 *aval;
 	 rhp++, aval++) {
 	char *strp, *oldstrp;
+	const char memo_equals[] = "memo=";
 
 	oldstrp = *aval;
 	if (*oldstrp == 'P') {
@@ -502,7 +514,44 @@ set_region_highlight(UNUSED(Param pm), char **aval)
 	while (inblank(*strp))
 	    strp++;
 
-	match_highlight(strp, &rhp->atr);
+	strp = (char*) match_highlight(strp, &rhp->atr);
+
+	while (inblank(*strp))
+	    strp++;
+
+	if (strpfx(memo_equals, strp)) {
+	    const char *memo_start = strp + strlen(memo_equals);
+	    const char *i, *memo_end;
+
+	    /* 
+	     * Forward compatibility: end parsing at a comma or whitespace to
+	     * allow the following extensions:
+	     *
+	     * - A fifth field: "0 20 bold memo=foo bar".
+	     *
+	     * - Additional attributes in the fourth field: "0 20 bold memo=foo,bar"
+	     *   and "0 20 bold memo=foo\0bar".
+	     *
+	     * For similar reasons, we don't flag an error if the fourth field
+	     * doesn't start with "memo=" as we expect.
+	     */
+	    i = memo_start;
+
+	    /* ### TODO: Consider optimizing the common case that memo_start to
+	     *           end-of-string is entirely ASCII */
+	    while (1) {
+		int nbytes;
+		convchar_t c = unmeta_one(i, &nbytes);
+
+		if (c == '\0' || c == ',' || inblank(c)) {
+		    memo_end = i;
+		    break;
+		} else
+		    i += nbytes;
+	    }
+	    rhp->memo = ztrduppfx(memo_start, memo_end - memo_start);
+	} else
+	    rhp->memo = NULL;
     }
 
     freearray(av);
@@ -2797,6 +2846,7 @@ zle_refresh_finish(void)
 
     if (region_highlights)
     {
+	free_region_highlights_memos();
 	zfree(region_highlights,
 	      sizeof(struct region_highlight) * n_region_highlights);
 	region_highlights = NULL;