[PATCH 7/7] diff --highlight-words: actually highlight words

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 diff.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/diff.c b/diff.c
index 47d22e3..68a847d 100644
--- a/diff.c
+++ b/diff.c
@@ -457,6 +457,50 @@ struct tagged_pointer {
 	enum pointer_tag tag;
 };
 
+static void emit_tagged_line(struct diff_options *o, const char *set,
+			     const char *line, int len,
+			     struct tagged_pointer *begin,
+			     struct tagged_pointer *end)
+{
+	struct tagged_pointer *current;
+	FILE *file = o->file;
+	const char *last_color = set;
+
+	for (current = begin; current < end; current++) {
+		struct tagged_pointer *next = current + 1;
+		const char *start = current->str;
+		const char *end = next->str;
+		const char *color = NULL;
+
+		switch (current->tag) {
+		case TAG_END_WORD:
+			color = set;
+			break;
+
+		case TAG_BEGIN_OLD_WORD:
+			color = GIT_COLOR_BG_RED GIT_COLOR_YELLOW;
+			break;
+
+		case TAG_BEGIN_NEW_WORD:
+			color = GIT_COLOR_BG_GREEN GIT_COLOR_BLUE;
+			break;
+
+		default:
+			break;
+		}
+
+		if (color && color != last_color) {
+			if (color == set)
+				fputs(GIT_COLOR_RESET, file);
+			fputs(color, file);
+			last_color = color;
+		}
+		while (end > start && end[-1] == '\n')
+			end--;
+		fwrite(start, end - start, 1, file);
+	}
+}
+
 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 			int first, const char *line, int len,
 			struct tagged_pointer *begin,
@@ -487,7 +531,10 @@ static void emit_line_0(struct diff_options *o, const char *set, const char *res
 		fputs(set, file);
 		if (!nofirst)
 			fputc(first, file);
-		fwrite(line, len, 1, file);
+		if (begin)
+			emit_tagged_line(o, set, line, len, begin, end);
+		else
+			fwrite(line, len, 1, file);
 		fputs(reset, file);
 	}
 	if (has_trailing_carriage_return)
@@ -531,7 +578,7 @@ static void emit_line_checked(const char *reset,
 			ws = NULL;
 	}
 
-	if (!ws)
+	if (!ws || begin)
 		emit_line_0(ecbdata->opt, set, reset, sign,
 			    line, len, begin, end);
 	else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
@@ -1312,7 +1359,7 @@ static void diff_words_flush_unified(struct emit_callback *ecb,
 		emit_line_checked(reset, ecb, begin_line->str,
 				  end_line->str - begin_line->str,
 				  color, ws_error_highlight, sign,
-				  NULL, NULL);
+				  begin_line, end_line);
 	}
 	b->mark_nr = 0;
 }
-- 
2.3.0.rc1.137.g477eb31