pretty: expand tabs in indented logs to make things line up properly
A commit log message sometimes tries to line things up using tabs,
assuming fixed-width font with the standard 8-place tab settings.
Viewing such a commit however does not work well in "git log", as
we indent the lines by prefixing 4 spaces in front of them.
This should all line up:
Column 1 Column 2
-------- --------
A B
ABCD EFGH
SPACES Instead of Tabs
Even with multi-byte UTF8 characters:
Column 1 Column 2
-------- --------
Ä B
åäö 100
A Møøse once bit my sister..
Tab-expand the lines in "git log --expand-tabs" output before
prefixing 4 spaces.
This is based on the patch by Linus Torvalds, but at this step, we
require an explicit command line option to enable the behaviour.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/pretty.c b/pretty.c
index 92b2870..c8b075d 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1629,6 +1629,72 @@
strbuf_release(&title);
}
+static int pp_utf8_width(const char *start, const char *end)
+{
+ int width = 0;
+ size_t remain = end - start;
+
+ while (remain) {
+ int n = utf8_width(&start, &remain);
+ if (n < 0 || !start)
+ return -1;
+ width += n;
+ }
+ return width;
+}
+
+static void strbuf_add_tabexpand(struct strbuf *sb,
+ const char *line, int linelen)
+{
+ const char *tab;
+
+ while ((tab = memchr(line, '\t', linelen)) != NULL) {
+ int width = pp_utf8_width(line, tab);
+
+ /*
+ * If it wasn't well-formed utf8, or it
+ * had characters with badly defined
+ * width (control characters etc), just
+ * give up on trying to align things.
+ */
+ if (width < 0)
+ break;
+
+ /* Output the data .. */
+ strbuf_add(sb, line, tab - line);
+
+ /* .. and the de-tabified tab */
+ strbuf_addchars(sb, ' ', 8 - (width % 8));
+
+ /* Skip over the printed part .. */
+ linelen -= tab + 1 - line;
+ line = tab + 1;
+ }
+
+ /*
+ * Print out everything after the last tab without
+ * worrying about width - there's nothing more to
+ * align.
+ */
+ strbuf_add(sb, line, linelen);
+}
+
+/*
+ * pp_handle_indent() prints out the intendation, and
+ * the whole line (without the final newline), after
+ * de-tabifying.
+ */
+static void pp_handle_indent(struct pretty_print_context *pp,
+ struct strbuf *sb, int indent,
+ const char *line, int linelen)
+{
+ strbuf_addchars(sb, ' ', indent);
+ if (pp->expand_tabs_in_log)
+ strbuf_add_tabexpand(sb, line, linelen);
+ else
+ strbuf_add(sb, line, linelen);
+}
+
void pp_remainder(struct pretty_print_context *pp,
const char **msg_p,
struct strbuf *sb,
@@ -1653,8 +1719,9 @@
strbuf_grow(sb, linelen + indent + 20);
if (indent)
- strbuf_addchars(sb, ' ', indent);
- strbuf_add(sb, line, linelen);
+ pp_handle_indent(pp, sb, indent, line, linelen);
+ else
+ strbuf_add(sb, line, linelen);
strbuf_addch(sb, '\n');
}
}
