Re: [PATCH v2 4/5] Make boundary characters for --color-words configurable

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> I haven't tested this at all (this is a lunchtime hack) and have a mild
> suspicion that it may have corner case miscounting (e.g. I blindly
> subtracts 3 from len when dealing with a line that represents a single
> token from the internal diff output --- do I always have 3 there even when
> the original file ends with an incomplete line?  I didn't check), but
> other than that I think this is a lot easier to read and follow.

And this adds "--color-words -b" support as an example.

The second hunk, however, is a bugfix to the previous one.  The code wants
the LF at the end of the line always returned as a single token.

---
 diff.c |   30 +++++++++++++++++++++++++++---
 1 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/diff.c b/diff.c
index 344aaa6..bce0626 100644
--- a/diff.c
+++ b/diff.c
@@ -357,6 +357,7 @@ struct emit_callback {
 	struct xdiff_emit_state xm;
 	int nparents, color_diff;
 	unsigned ws_rule;
+	struct diff_options *diffopt;
 	sane_truncate_fn truncate;
 	const char **label_path;
 	struct diff_words_data *diff_words;
@@ -378,19 +379,36 @@ static size_t diff_words_tokenize(struct emit_callback *ecbdata,
 
 	if (!len)
 		return 0;
+	/*
+	 * Always return LF at the end as a single separate token.
+	 */
+	if ((len == 1) && *line == '\n')
+		return 1;
 
 	is_space = isspace(*line);
 	while (len && (isspace(*line) == is_space)) {
 		line++;
 		len--;
 	}
+	if (is_space && !len)
+		line--;
 	return line - line0;
 }
 
+static int token_is_ws_only(char *line, size_t len)
+{
+	while (len--)
+		if (!isspace(*line))
+			return 0;
+	return 1;
+}
+
 static void diff_words_append(struct emit_callback *ecbdata,
 			      char *line, unsigned long len,
 			      struct strbuf *text)
 {
+	struct diff_options *diffopt = ecbdata->diffopt;
+
 	/* Skip leading +/- first. */
 	line++;
 	len--;
@@ -407,9 +425,14 @@ static void diff_words_append(struct emit_callback *ecbdata,
 			 * so that we can recover the original
 			 * end-of-line easily.  Stupid, but works.
 			 */
-			strbuf_add(text, " ", 1);
-			strbuf_add(text, line, token_len);
-			strbuf_add(text, "\n", 1);
+			if ((diffopt->xdl_opts & XDF_IGNORE_WHITESPACE) &&
+			    token_is_ws_only(line, token_len)) {
+				strbuf_add(text, "  \n", 3);
+			} else {
+				strbuf_add(text, " ", 1);
+				strbuf_add(text, line, token_len);
+				strbuf_add(text, "\n", 1);
+			}
 			len -= token_len;
 			line += token_len;
 		} else {
@@ -1447,6 +1470,7 @@ static void builtin_diff(const char *name_a,
 		ecbdata.found_changesp = &o->found_changes;
 		ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
 		ecbdata.file = o->file;
+		ecbdata.diffopt = o;
 		xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 		xecfg.ctxlen = o->context;
 		xecfg.flags = XDL_EMIT_FUNCNAMES;