Am 20.12.2013 08:04, schrieb Jeff King:
> On Fri, Dec 20, 2013 at 07:51:00AM +0100, Johannes Sixt wrote:
>
>>> for (i = 1; i < argc && *argv[i] == '-'; i++) {
>>> const char *arg = argv[i];
>>> + const char *optarg;
>>>
>>> - if (starts_with(arg, "--upload-pack=")) {
>>> - args.uploadpack = arg + 14;
>>> + if ((optarg = skip_prefix(arg, "--upload-pack=")) != NULL) {
>>> + args.uploadpack = optarg;
>>
>> Quite frankly, I do not think this is an improvement. The old code is
>> *MUCH* easier to understand because "starts_with" is clearly a predicate
>> that is either true or false, but the code with "skip_prefix" is much
>> heavier on the eye with its extra level of parenthesis. That it removes a
>> hard-coded constant does not count much IMHO because it is very clear
>> where the value comes from.
>
> Yeah, I agree that is unfortunate. Maybe we could have the best of both
> worlds, like:
>
> if (starts_with(arg, "--upload-pack=", &optarg))
> ... use optarg ...
>
> Probably we do not want to call it just "starts_with", as quite a few
> callers to do not care about what comes next, and would just pass NULL.
>
> I cannot seem to think of a good name, though, as the "with" means that
> obvious things like "starts_with_value" naturally parse as a single
> (nonsensical) sentence. Something like "parse_prefix" would work, but
> it is not as clearly a predicate as "starts_with" (but we have at least
> gotten rid of the extra parentheses).
>
> Elsewhere in the thread, the concept was discussed of returning the full
> string to mean "did not match", which makes some other idioms simpler
> (but IMHO makes the simple cases like this even harder to read). My
> proposal splits the "start of string" out parameter from the boolean
> return, so it handles both cases naturally:
>
> /* here we care if we saw the prefix, as above */
> if (parse_prefix(foo, prefix, &the_rest))
> ...
>
> /*
> * and here we do not care, and just want to optionally strip the
> * prefix, and take the full value otherwise; we just have to ignore
> * the return value in this case.
> */
> parse_prefix(foo, prefix, &foo);
It adds a bit of redundancy, but overall I like it. It fits the common
case very well and looks nice. The patch below converts all calls of
skip_prefix as well as the usage of starts_with and a magic number in
builtin/fetch-pack.c.
I wonder how many of the 400+ uses of starts_with remain after a
parse_prefix crusade. If only a few remain then it may make sense
to unite the two functions under a common name.
---
advice.c | 5 ++++-
builtin/branch.c | 6 +++---
builtin/clone.c | 13 ++++++++-----
builtin/commit.c | 6 ++----
builtin/fetch-pack.c | 14 +++++++-------
builtin/fmt-merge-msg.c | 4 ++--
builtin/push.c | 7 +++----
builtin/remote.c | 4 +---
column.c | 5 +++--
config.c | 3 +--
credential-cache--daemon.c | 6 ++----
credential.c | 3 +--
git-compat-util.h | 1 +
parse-options.c | 11 ++++++-----
strbuf.c | 12 +++++++++---
transport.c | 6 +++++-
urlmatch.c | 3 +--
17 files changed, 59 insertions(+), 50 deletions(-)
diff --git a/advice.c b/advice.c
index 3eca9f5..75fae9c 100644
--- a/advice.c
+++ b/advice.c
@@ -63,9 +63,12 @@ void advise(const char *advice, ...)
int git_default_advice_config(const char *var, const char *value)
{
- const char *k = skip_prefix(var, "advice.");
+ const char *k;
int i;
+ if (!parse_prefix(var, "advice.", &k))
+ return 0;
+
for (i = 0; i < ARRAY_SIZE(advice_config); i++) {
if (strcmp(k, advice_config[i].name))
continue;
diff --git a/builtin/branch.c b/builtin/branch.c
index b4d7716..dae0d82 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -294,13 +294,13 @@ static char *resolve_symref(const char *src, const char
*prefix)
{
unsigned char sha1[20];
int flag;
- const char *dst, *cp;
+ const char *dst;
dst = resolve_ref_unsafe(src, sha1, 0, &flag);
if (!(dst && (flag & REF_ISSYMREF)))
return NULL;
- if (prefix && (cp = skip_prefix(dst, prefix)))
- dst = cp;
+ if (prefix)
+ parse_prefix(dst, prefix, &dst);
return xstrdup(dst);
}
diff --git a/builtin/clone.c b/builtin/clone.c
index f98f529..e62fa26 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -578,11 +578,12 @@ static void update_remote_refs(const struct ref *refs,
static void update_head(const struct ref *our, const struct ref *remote,
const char *msg)
{
- if (our && starts_with(our->name, "refs/heads/")) {
+ const char *head;
+
+ if (our && parse_prefix(our->name, "refs/heads/", &head)) {
/* Local default branch link */
create_symref("HEAD", our->name, NULL);
if (!option_bare) {
- const char *head = skip_prefix(our->name,
"refs/heads/");
update_ref(msg, "HEAD", our->old_sha1, NULL, 0,
DIE_ON_ERR);
install_branch_config(0, head, option_origin,
our->name);
}
@@ -696,9 +697,11 @@ static void write_refspec_config(const char*
src_ref_prefix,
strbuf_addf(&value, "+%s:%s%s",
our_head_points_at->name,
branch_top->buf, option_branch);
} else if (remote_head_points_at) {
- strbuf_addf(&value, "+%s:%s%s",
remote_head_points_at->name,
- branch_top->buf,
-
skip_prefix(remote_head_points_at->name, "refs/heads/"));
+ const char *name = remote_head_points_at->name;
+ const char *head = NULL;
+ parse_prefix(name, "refs/heads/", &head);
+ strbuf_addf(&value, "+%s:%s%s",
+ name, branch_top->buf, head);
}
/*
* otherwise, the next "git fetch" will
diff --git a/builtin/commit.c b/builtin/commit.c
index 3767478..e9bff59 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -934,7 +934,7 @@ static int message_is_empty(struct strbuf *sb)
static int template_untouched(struct strbuf *sb)
{
struct strbuf tmpl = STRBUF_INIT;
- char *start;
+ const char *start = sb->buf;
if (cleanup_mode == CLEANUP_NONE && sb->len)
return 0;
@@ -943,9 +943,7 @@ static int template_untouched(struct strbuf *sb)
return 0;
stripspace(&tmpl, cleanup_mode == CLEANUP_ALL);
- start = (char *)skip_prefix(sb->buf, tmpl.buf);
- if (!start)
- start = sb->buf;
+ parse_prefix(start, tmpl.buf, &start);
strbuf_release(&tmpl);
return rest_is_empty(sb, start - sb->buf);
}
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index 8b8978a2..d673986 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -46,14 +46,14 @@ int cmd_fetch_pack(int argc, const char **argv, const char
*prefix)
args.uploadpack = "git-upload-pack";
for (i = 1; i < argc && *argv[i] == '-'; i++) {
- const char *arg = argv[i];
+ const char *optarg, *arg = argv[i];
- if (starts_with(arg, "--upload-pack=")) {
- args.uploadpack = arg + 14;
+ if (parse_prefix(arg, "--upload-pack=", &optarg)) {
+ args.uploadpack = optarg;
continue;
}
- if (starts_with(arg, "--exec=")) {
- args.uploadpack = arg + 7;
+ if (parse_prefix(arg, "--exec=", &optarg)) {
+ args.uploadpack = optarg;
continue;
}
if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
@@ -89,8 +89,8 @@ int cmd_fetch_pack(int argc, const char **argv, const char
*prefix)
args.verbose = 1;
continue;
}
- if (starts_with(arg, "--depth=")) {
- args.depth = strtol(arg + 8, NULL, 0);
+ if (parse_prefix(arg, "--depth=", &optarg)) {
+ args.depth = strtol(optarg, NULL, 0);
continue;
}
if (!strcmp("--no-progress", arg)) {
diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index 3906eda..ce889e3 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -297,8 +297,8 @@ static void credit_people(struct strbuf *out,
if (!them->nr ||
(them->nr == 1 &&
me &&
- (me = skip_prefix(me, them->items->string)) != NULL &&
- skip_prefix(me, " <")))
+ parse_prefix(me, them->items->string, &me) &&
+ starts_with(me, " <")))
return;
strbuf_addf(out, "\n%c %s ", comment_line_char, label);
add_people_count(out, them);
diff --git a/builtin/push.c b/builtin/push.c
index a73982a..f040e82 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -88,11 +88,10 @@ static NORETURN int die_push_simple(struct branch *branch,
struct remote *remote
* them the big ugly fully qualified ref.
*/
const char *advice_maybe = "";
- const char *short_upstream =
- skip_prefix(branch->merge[0]->src, "refs/heads/");
+ const char *short_upstream = branch->merge[0]->src;
+
+ parse_prefix(short_upstream, "refs/heads/", &short_upstream);
- if (!short_upstream)
- short_upstream = branch->merge[0]->src;
/*
* Don't show advice for people who explicitly set
* push.default.
diff --git a/builtin/remote.c b/builtin/remote.c
index b3ab4cf..30d1987 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -250,9 +250,7 @@ static struct string_list branch_list;
static const char *abbrev_ref(const char *name, const char *prefix)
{
- const char *abbrev = skip_prefix(name, prefix);
- if (abbrev)
- return abbrev;
+ parse_prefix(name, prefix, &name);
return name;
}
#define abbrev_branch(name) abbrev_ref((name), "refs/heads/")
diff --git a/column.c b/column.c
index 9367ba5..dfb2392 100644
--- a/column.c
+++ b/column.c
@@ -336,8 +336,9 @@ static int column_config(const char *var, const char *value,
int git_column_config(const char *var, const char *value,
const char *command, unsigned int *colopts)
{
- const char *it = skip_prefix(var, "column.");
- if (!it)
+ const char *it;
+
+ if (!parse_prefix(var, "column.", &it))
return 0;
if (!strcmp(it, "ui"))
diff --git a/config.c b/config.c
index d969a5a..ee42010 100644
--- a/config.c
+++ b/config.c
@@ -133,8 +133,7 @@ int git_config_include(const char *var, const char *value,
void *data)
if (ret < 0)
return ret;
- type = skip_prefix(var, "include.");
- if (!type)
+ if (!parse_prefix(var, "include.", &type))
return ret;
if (!strcmp(type, "path"))
diff --git a/credential-cache--daemon.c b/credential-cache--daemon.c
index 390f194..3823a38 100644
--- a/credential-cache--daemon.c
+++ b/credential-cache--daemon.c
@@ -109,14 +109,12 @@ static int read_request(FILE *fh, struct credential *c,
const char *p;
strbuf_getline(&item, fh, '\n');
- p = skip_prefix(item.buf, "action=");
- if (!p)
+ if (!parse_prefix(item.buf, "action=", &p))
return error("client sent bogus action line: %s", item.buf);
strbuf_addstr(action, p);
strbuf_getline(&item, fh, '\n');
- p = skip_prefix(item.buf, "timeout=");
- if (!p)
+ if (!parse_prefix(item.buf, "timeout=", &p))
return error("client sent bogus timeout line: %s", item.buf);
*timeout = atoi(p);
diff --git a/credential.c b/credential.c
index e54753c..fd148a0 100644
--- a/credential.c
+++ b/credential.c
@@ -40,8 +40,7 @@ static int credential_config_callback(const char *var, const
char *value,
struct credential *c = data;
const char *key, *dot;
- key = skip_prefix(var, "credential.");
- if (!key)
+ if (!parse_prefix(var, "credential.", &key))
return 0;
if (!value)
diff --git a/git-compat-util.h b/git-compat-util.h
index b73916b..0a8354a 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -350,6 +350,7 @@ extern void set_die_routine(NORETURN_PTR void
(*routine)(const char *err, va_lis
extern void set_error_routine(void (*routine)(const char *err, va_list
params));
extern void set_die_is_recursing_routine(int (*routine)(void));
+extern int parse_prefix(const char *str, const char *prefix, const char
**rest);
extern int starts_with(const char *str, const char *prefix);
extern int prefixcmp(const char *str, const char *prefix);
extern int ends_with(const char *str, const char *suffix);
diff --git a/parse-options.c b/parse-options.c
index 7b8d3fa..1e25203 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -238,7 +238,8 @@ static int parse_long_opt(struct parse_opt_ctx_t *p, const
char *arg,
continue;
again:
- rest = skip_prefix(arg, long_name);
+ rest = NULL;
+ parse_prefix(arg, long_name, &rest);
if (options->type == OPTION_ARGUMENT) {
if (!rest)
continue;
@@ -287,12 +288,12 @@ is_abbreviated:
continue;
}
flags |= OPT_UNSET;
- rest = skip_prefix(arg + 3, long_name);
/* abbreviated and negated? */
- if (!rest && starts_with(long_name, arg + 3))
- goto is_abbreviated;
- if (!rest)
+ if (!parse_prefix(arg + 3, long_name, &rest)) {
+ if (starts_with(long_name, arg + 3))
+ goto is_abbreviated;
continue;
+ }
}
if (*rest) {
if (*rest != '=')
diff --git a/strbuf.c b/strbuf.c
index 83caf4a..b78bc44 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -1,15 +1,21 @@
#include "cache.h"
#include "refs.h"
-int starts_with(const char *str, const char *prefix)
+int parse_prefix(const char *str, const char *prefix, const char **rest)
{
for (; ; str++, prefix++)
- if (!*prefix)
+ if (!*prefix) {
+ *rest = str;
return 1;
- else if (*str != *prefix)
+ } else if (*str != *prefix)
return 0;
}
+int starts_with(const char *str, const char *prefix)
+{
+ return parse_prefix(str, prefix, &str);
+}
+
int prefixcmp(const char *str, const char *prefix)
{
for (; ; str++, prefix++)
diff --git a/transport.c b/transport.c
index 824c5b9..775f2b1 100644
--- a/transport.c
+++ b/transport.c
@@ -191,7 +191,11 @@ static void set_upstreams(struct transport *transport,
struct ref *refs,
static const char *rsync_url(const char *url)
{
- return !starts_with(url, "rsync://") ? skip_prefix(url, "rsync:") : url;
+ const char *rest = NULL;
+ if (starts_with(url, "rsync://"))
+ return url;
+ parse_prefix(url, "rsync:", &rest);
+ return rest;
}
static struct ref *get_refs_via_rsync(struct transport *transport, int
for_push)
diff --git a/urlmatch.c b/urlmatch.c
index ec87cba..dfd1fa7 100644
--- a/urlmatch.c
+++ b/urlmatch.c
@@ -483,8 +483,7 @@ int urlmatch_config_entry(const char *var, const char
*value, void *cb)
int user_matched = 0;
int retval;
- key = skip_prefix(var, collect->section);
- if (!key || *(key++) != '.') {
+ if (!parse_prefix(var, collect->section, &key) || *(key++) != '.') {
if (collect->cascade_fn)
return collect->cascade_fn(var, value, cb);
return 0; /* not interested */
--
1.8.5.2
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