diff --color: color blank-at-eof

Since the coloring logic processed the patch output one line at a time, we
couldn't easily color code the new blank lines at the end of file.

Reuse the adds_blank_at_eof() function to find where the runs of such
blank lines start, keep track of the line number in the preimage while
processing the patch output one line at a time, and paint the new blank
lines that appear after that line to implement this.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff.c b/diff.c
index c19c4760fe90a6ead26bbd240b0b9f64e2d60397..2b285b8ce90faed3218d5af1524283fc65c9540d 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -491,6 +491,8 @@ struct emit_callback {
        struct xdiff_emit_state xm;
        int color_diff;
        unsigned ws_rule;
+       int blank_at_eof;
+       int lno_in_preimage;
        sane_truncate_fn truncate;
        const char **label_path;
        struct diff_words_data *diff_words;
@@ -547,6 +549,12 @@ static void emit_add_line(const char *reset, struct emit_callback *ecbdata, cons
 
        if (!*ws)
                emit_line(ecbdata->file, set, reset, line, len);
+       else if ((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
+                ecbdata->blank_at_eof &&
+                (ecbdata->blank_at_eof <= ecbdata->lno_in_preimage) &&
+                ws_blank_line(line + 1, len - 1, ecbdata->ws_rule))
+               /* Blank line at EOF */
+               emit_line(ecbdata->file, ws, reset, line, len);
        else {
                /* Emit just the prefix, then the rest. */
                emit_line(ecbdata->file, set, reset, line, 1);
@@ -573,9 +581,16 @@ static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, u
        return allot - l;
 }
 
+static int find_preimage_lno(const char *line)
+{
+       char *p = strchr(line, '-');
+       if (!p)
+               return 0; /* should not happen */
+       return strtol(p+1, NULL, 10);
+}
+
 static void fn_out_consume(void *priv, char *line, unsigned long len)
 {
-       int color;
        struct emit_callback *ecbdata = priv;
        const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
        const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
@@ -598,6 +613,7 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
 
        if (line[0] == '@') {
                len = sane_truncate_line(ecbdata, line, len);
+               ecbdata->lno_in_preimage = find_preimage_lno(line);
                emit_line(ecbdata->file,
                          diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
                          reset, line, len);
@@ -611,7 +627,6 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
                return;
        }
 
-       color = DIFF_PLAIN;
        if (ecbdata->diff_words) {
                if (line[0] == '-') {
                        diff_words_append(line, len,
@@ -630,14 +645,13 @@ static void fn_out_consume(void *priv, char *line, unsigned long len)
                emit_line(ecbdata->file, plain, reset, line, len);
                return;
        }
-       if (line[0] == '-')
-               color = DIFF_FILE_OLD;
-       else if (line[0] == '+')
-               color = DIFF_FILE_NEW;
-       if (color != DIFF_FILE_NEW) {
-               emit_line(ecbdata->file,
-                         diff_get_color(ecbdata->color_diff, color),
-                         reset, line, len);
+
+       if (line[0] != '+') {
+               const char *color =
+                       diff_get_color(ecbdata->color_diff,
+                                      line[0] == '-' ? DIFF_FILE_OLD : DIFF_PLAIN);
+               ecbdata->lno_in_preimage++;
+               emit_line(ecbdata->file, color, reset, line, len);
                return;
        }
        emit_add_line(reset, ecbdata, line, len);
@@ -1557,6 +1571,9 @@ static void builtin_diff(const char *name_a,
                ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
                ecbdata.found_changesp = &o->found_changes;
                ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
+               if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
+                       ecbdata.blank_at_eof =
+                               adds_blank_at_eof(&mf1, &mf2, ecbdata.ws_rule);
                ecbdata.file = o->file;
                xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
                xecfg.ctxlen = o->context;

diff --git a/t/t4019-diff-wserror.sh b/t/t4019-diff-wserror.sh
index 1517fff9c64f711a6fd3dda6361a338d0e1fdfe0..1e75f1a1108f1d82e65511c9cfc19fee70866205 100755 (executable)
--- a/t/t4019-diff-wserror.sh
+++ b/t/t4019-diff-wserror.sh
@@ -190,4 +190,13 @@ test_expect_success 'do not color trailing cr in context' '
 
 '
 
+test_expect_success 'color new trailing blank lines' '
+       { echo a; echo b; echo; echo; } >x &&
+       git add x &&
+       { echo a; echo; echo; echo; echo; } >x &&
+       git diff --color x >output &&
+       cnt=$(grep "${blue_grep}" output | wc -l) &&
+       test $cnt = 2
+'
+
 test_done