Am 08.08.19 um 21:04 schrieb Jeff Hostetler:
> On 8/8/2019 2:05 PM, Junio C Hamano wrote:
>> Having made the primary purpose of the helper clearer leads me to
>> wonder if "do not add SP before the first element, i.e. argv[0]", is
>> really what we want. If we always clear the *dst strbuf before
>> starting to serialize argv[] into it, then the behaviour would make
>> sense, but we do not---we are "appending".
>>
>> As long as we are appending, would we be better off doing something
>> sillily magical like this instead, I have to wonder?
>>
>> void sq_append_strings_quoted(struct strbuf *buf, const char **av)
>> {
>> int i;
>>
>> for (i = 0; av[i]; i++) {
>> if (buf->len)
>> strbuf_addch(buf, ' ');
>> sq_quote_buf_pretty(buf, argv[0]);
>> }
>> }
>>
>> That is, "if we are appending to an existing string, have SP to
>> separate the first element from that existing string; treat the
>> remaining elements the same way (if the buffer is empty, there is no
>> point adding SP at the beginning)".
>
> I don't think that would do what we want. We don't know what the
> caller's expectations are. In my uses in commits 6/7 and 7/7 I
> already added the leading chars I wanted in the strbuf before calling
> sq_quote_argv_pretty_ltrim() and assumed the output would be a true
> append. For example:
>
> + strbuf_addf(&buf_payload, "alias:%s argv:[", alias);
> + sq_quote_argv_pretty_ltrim(&buf_payload, argv);
> + strbuf_addch(&buf_payload, ']');
>
> I like your suggestion of putting my new function in the _append_
> category. I think I'll add the 3rd arg to this and then it will
> be completely specified and I can get rid of the _ltrim suffix.
Two observations:
If callers want to add something before a joined delimited list, they
already can with a strbuf_add* call. No need to add that feature to
a function that joins lists.
And repetitions of repetitions (loops) are boring.
Apologies in advance for any coffee stains on your monitor, but
here's how I would start, probably followed by attempts to inline the
functions that become trivial wrappers:
---
quote.c | 18 ++++--------------
strbuf.c | 20 +++++++++++++-------
strbuf.h | 8 ++++++++
3 files changed, 25 insertions(+), 21 deletions(-)
diff --git a/quote.c b/quote.c
index 7f2aa6faa4..f422188852 100644
--- a/quote.c
+++ b/quote.c
@@ -74,24 +74,14 @@ void sq_quotef(struct strbuf *dst, const char *fmt, ...)
void sq_quote_argv(struct strbuf *dst, const char **argv)
{
- int i;
-
- /* Copy into destination buffer. */
- strbuf_grow(dst, 255);
- for (i = 0; argv[i]; ++i) {
- strbuf_addch(dst, ' ');
- sq_quote_buf(dst, argv[i]);
- }
+ strbuf_addch(dst, ' ');
+ strbuf_map_join_argv(dst, argv, sq_quote_buf, " ");
}
void sq_quote_argv_pretty(struct strbuf *dst, const char **argv)
{
- int i;
-
- for (i = 0; argv[i]; i++) {
- strbuf_addch(dst, ' ');
- sq_quote_buf_pretty(dst, argv[i]);
- }
+ strbuf_addch(dst, ' ');
+ strbuf_map_join_argv(dst, argv, sq_quote_buf_pretty, " ");
}
static char *sq_dequote_step(char *arg, char **next)
diff --git a/strbuf.c b/strbuf.c
index d30f916858..d337853b53 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -304,17 +304,23 @@ void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
strbuf_setlen(sb, sb->len + sb2->len);
}
+void strbuf_map_join_argv(struct strbuf *sb, const char **argv,
+ void (*fn)(struct strbuf *, const char *),
+ const char *separator)
+{
+ while (*argv) {
+ fn(sb, *argv++);
+ if (*argv)
+ strbuf_addstr(sb, separator);
+ }
+}
+
const char *strbuf_join_argv(struct strbuf *buf,
int argc, const char **argv, char delim)
{
- if (!argc)
- return buf->buf;
+ char separator[] = { delim, '\0' };
- strbuf_addstr(buf, *argv);
- while (--argc) {
- strbuf_addch(buf, delim);
- strbuf_addstr(buf, *(++argv));
- }
+ strbuf_map_join_argv(buf, argv, strbuf_addstr, separator);
return buf->buf;
}
diff --git a/strbuf.h b/strbuf.h
index f62278a0be..7adeff94a7 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -297,6 +297,14 @@ static inline void strbuf_addstr(struct strbuf *sb, const char *s)
*/
void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2);
+/**
+ * Apply `fn` to `sb` and each element of the NULL-terminated array
+ * `argv`. Add `separator` between these invocations.
+ */
+void strbuf_map_join_argv(struct strbuf *sb, const char **argv,
+ void (*fn)(struct strbuf *, const char *),
+ const char *separator);
+
/**
* Join the arguments into a buffer. `delim` is put between every
* two arguments.
--
2.22.0
