This uses the strbuf_nested_expand() mechanism introduced earlier
to demonstrate how to implement a nested string function. It does
not "wrap" using the line-wrap code, but lifting the change by Dscho
and plugging it in should be a trivial exercise.
The overall idea is to parse something like "%[w(72,4,8)%an %ae %s%]" in
these steps:
#1 "%[" introduces the nested string function.
#2 After that, a name identifies what function to call.
#3 The function parses its parameters ("(72,4,8)" in the above example),
and makes a nested expansion on the remainder of the format string.
#4 The nested expansion is terminated at "%]" and returned to the
function.
#5 The function massages the string returned from #4, and the result
becomes the expansion of the whole thing.
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
pretty.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 84 insertions(+), 0 deletions(-)
diff --git a/pretty.c b/pretty.c
index 587101f..a8a38c3 100644
--- a/pretty.c
+++ b/pretty.c
@@ -595,6 +595,80 @@ static void format_decoration(struct strbuf *sb, const struct commit *commit)
strbuf_addch(sb, ')');
}
+typedef int (*string_fmt_fn)(struct strbuf *sb, const char *placeholder, void *context);
+static size_t format_commit_item(struct strbuf *, const char *, void *);
+
+static int wrap_fn(struct strbuf *sb, const char *placeholder, void *context)
+{
+ const char *template = placeholder;
+ char *endptr;
+ long width = 0, indent1 = 0, indent2 = 0;
+
+ width = strtol(template, &endptr, 10);
+ if (*endptr == ',') {
+ template = endptr + 1;
+ indent1 = strtol(template, &endptr, 10);
+ if (*endptr == ',') {
+ template = endptr + 1;
+ indent2 = strtol(template, &endptr, 10);
+ }
+ }
+ if (*endptr++ != ')')
+ return 0;
+
+ template = endptr;
+ strbuf_nested_expand(sb, &template, format_commit_item, context);
+ if (*template++ != ']')
+ return 0;
+
+ /*
+ * NEEDSWORK: here you wrap the contents of substr with
+ * strbuf_wrap(&substr, width, indent1, indent2);
+ *
+ * ... but I am too lazy to do that here, and I just demonstrate
+ * how it should work by just upcasing the result ;-)
+ */
+ {
+ int i;
+ for (i = 0; i < sb->len; i++)
+ sb->buf[i] = toupper(sb->buf[i]);
+ }
+ return template - placeholder;
+}
+
+static struct {
+ const char *name;
+ string_fmt_fn fn;
+} format_fn_list[] = {
+ { "w(", wrap_fn }
+};
+
+static size_t format_fn(struct strbuf *sb, const char *placeholder,
+ void *context)
+{
+ const char *template = placeholder;
+ size_t consumed;
+ struct strbuf substr = STRBUF_INIT;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(format_fn_list); i++)
+ if (!prefixcmp(template, format_fn_list[i].name))
+ break;
+ if (ARRAY_SIZE(format_fn_list) <= i)
+ return 0;
+ template += strlen(format_fn_list[i].name);
+ consumed = format_fn_list[i].fn(&substr, template, context);
+ if (!consumed) {
+ strbuf_release(&substr);
+ return 0;
+ }
+
+ strbuf_add(sb, substr.buf, substr.len);
+ template += consumed;
+ strbuf_release(&substr);
+ return template - placeholder;
+}
+
static size_t format_commit_item(struct strbuf *sb, const char *placeholder,
void *context)
{
@@ -603,9 +677,19 @@ static size_t format_commit_item(struct strbuf *sb, const char *placeholder,
const char *msg = commit->buffer;
struct commit_list *p;
int h1, h2;
+ size_t nested;
/* these are independent of the commit */
switch (placeholder[0]) {
+ case ']':
+ return -1;
+ case '[':
+ /*
+ * %[func(arg...) string %]: we consumed the opening '['
+ * and the callee consumed up to the closing '%]'.
+ */
+ nested = format_fn(sb, placeholder + 1, context);
+ return nested ? 1 + nested : 0;
case 'C':
if (placeholder[1] == '(') {
const char *end = strchr(placeholder + 2, ')');
--
1.6.5.99.g9ed7e
--
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