On 8/8/2019 6:49 PM, René Scharfe wrote:
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:
Um, yeah, I must say that I didn't expect the conversation to turn to
map-style functions and a change in design styles. I think it would be
better to have that conversation in a different patch series and not mix
it with my trace2 janitoring.
I'm going to push a V3 that does just the minimum to have a sq_ function
that joins the args with a space delimiter (and without the leading
space) and re-write the existing function to call it after adding the
legacy leading space. This will let existing callers continue to work
as is. And they can be converted if/when anyone wants to dig into them.
---
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, ' ');
If I'm reading this correctly, this has slightly different behavior
than the original version. Perhaps:
if (argv[0])
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
