Re: [PATCHv2] submodule: Port resolve_relative_url from shell to C
- From
Johannes Sixt <j6t@kdbg.org>
- Date
- Dec 17, 2015, 18:55 UTC
- Message-ID
- <5673052F.7050000@kdbg.org>
- In-Reply-To
- <1450311999-3992-2-git-send-email-sbeller@google.com>
Am 17.12.2015 um 01:26 schrieb Stefan Beller:
Show 22 quoted lines
> This reimplements the helper function `resolve_relative_url` in shell > in C. This functionality is needed in C for introducing the groups > feature later on. When using groups, the user should not need to run > `git submodule init`, but it should be implicit at all appropriate places, > which are all in C code. As the we would not just call out to `git > submodule init`, but do a more fine grained structure there, we actually > need all the init functionality in C before attempting the groups > feature. To get the init functionality in C, rewriting the > resolve_relative_url subfunction is a major step. > > This also improves the performance: > (Best out of 3) time ./t7400-submodule-basic.sh > Before: > real 0m9.575s > user 0m2.683s > sys 0m6.773s > After: > real 0m9.293s > user 0m2.691s > sys 0m6.549s > > That's about 3%.
I appreciate this effort as it should help us on Windows. Although the numbers (and my own timings) suggest that this is only a small step forward. That's not surprising as the patch removes only two forks.
As to the implementation, find a patch below that removes the ifdefs and a few other suggestions. It is a mechanical conversion without understanding what relative_url() does. I have the gut feeling that the two strbuf_addf towards the end of the function can be contracted and the temporarily allocate copy in 'out' can be removed.
If there were a few examples in the comment above the function, it would be much simpler to understand.
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c index b925bed..8ec0975 100644 --- a/builtin/submodule--helper.c +++ b/builtin/submodule--helper.c @@ -11,6 +11,7 @@ #include "run-command.h" #include "remote.h" #include "refs.h" +#include "connect.h" static const char *get_default_remote(void) { @@ -31,34 +32,23 @@ static const char *get_default_remote(void) return xstrdup(dest); } -static int has_same_dir_prefix(const char *str, const char **out) +static int starts_with_dot_slash(const char *str) { -#ifdef GIT_WINDOWS_NATIVE - return skip_prefix(str, "./", out) - || skip_prefix(str, ".\\", out); -#else - return skip_prefix(str, "./", out); -#endif + return str[0] == '.' && is_dir_sep(str[1]); } -static int has_upper_dir_prefix(const char *str, const char **out) +static int starts_with_dot_dot_slash(const char *str) { -#ifdef GIT_WINDOWS_NATIVE - return skip_prefix(str, "../", out) - || skip_prefix(str, "..\\", out); -#else - return skip_prefix(str, "../", out); -#endif + return str[0] == '.' && str[1] == '.' && is_dir_sep(str[2]); } -static char *last_dir_separator(const char *str) +static char *last_dir_separator(char *str) { -#ifdef GIT_WINDOWS_NATIVE - return strrchr(str, "/") - || strrchr(str, "\\"); -#else - return strrchr(str, '/'); -#endif + char* p = str + strlen(str); + while (p-- != str) + if (is_dir_sep(*p)) + return p; + return NULL; } /* @@ -85,9 +75,10 @@ static const char *relative_url(const char *url, const char *up_path) size_t len; char *remoteurl = NULL; char *sep = "/"; - const char *out; + char *out; struct strbuf sb = STRBUF_INIT; const char *remote = get_default_remote(); + strbuf_addf(&sb, "remote.%s.url", remote); if (git_config_get_string(sb.buf, &remoteurl)) @@ -98,22 +89,23 @@ static const char *relative_url(const char *url, const char *up_path) if (is_dir_sep(remoteurl[len])) remoteurl[len] = '\0'; - if (strchr(remoteurl, ':') || is_dir_sep(*remoteurl)) + if (!url_is_local_not_ssh(remoteurl) || is_absolute_path(remoteurl)) is_relative = 0; - else if (has_same_dir_prefix(remoteurl, &out) || - has_upper_dir_prefix(remoteurl, &out)) + else if (starts_with_dot_slash(remoteurl) || + starts_with_dot_dot_slash(remoteurl)) is_relative = 1; else { is_relative = 1; strbuf_reset(&sb); strbuf_addf(&sb, "./%s", remoteurl); + free(remoteurl); remoteurl = strbuf_detach(&sb, NULL); } while (url) { - if (has_upper_dir_prefix(url, &out)) { + if (starts_with_dot_dot_slash(url)) { char *rfind; - url = out; + url += 3; rfind = last_dir_separator(remoteurl); if (rfind) @@ -130,22 +122,23 @@ static const char *relative_url(const char *url, const char *up_path) remoteurl = "."; } } - } else if (has_same_dir_prefix(url, &out)) - url = out; - else + } else if (starts_with_dot_slash(url)) { + url += 2; + } else break; } strbuf_reset(&sb); strbuf_addf(&sb, "%s%s%s", remoteurl, sep, url); - if (!has_same_dir_prefix(sb.buf, &out)) - out = sb.buf; - out = xstrdup(out); + if (starts_with_dot_slash(sb.buf)) + out = strdup(sb.buf + 2); + else + out = xstrdup(sb.buf); strbuf_reset(&sb); strbuf_addf(&sb, "%s%s", is_relative && up_path ? up_path : "", out); - free((char*)out); + free(out); return strbuf_detach(&sb, NULL); }