Re: [PATCH] Provide a dirname() function when NO_LIBGEN_H=YesPlease
- From
Ramsay Jones <ramsay@ramsayjones.plus.com>
- Date
- Sep 30, 2015, 18:57 UTC
- Message-ID
- <560C30B1.3010508@ramsayjones.plus.com>
- In-Reply-To
- <25a2598e756959f55f06ae6b4dc6f448e3b6b127.1443624188.git.johannes.schindelin@gmx.de>
Hi Johannes,
On 30/09/15 15:50, Johannes Schindelin wrote:
Show 6 quoted lines
> When there is no `libgen.h` to our disposal, we miss the `dirname()` > function. > > So far, we only had one user of that function: credential-cache--daemon > (which was only compiled when Unix sockets are available, anyway). But > now we also have `builtin/am.c` as user, so we need it.
Yes, many moons ago (on my old 32-bit laptop) when I was still 'working' with MinGW I noticed this same thing while looking into providing a win32 emulation of unix sockets. So, I had to look into this at the same time. Since this didn't progress, I didn't mention the libgen issue.
Anyway, I still have a 'test-libgen.c' file (attached) from back then that contains some tests. I don't quite recall what the final state of this code was, but it was intended to test _existing_ libgen implementations as well as provide a 'git' version which would work on MinGW, cygwin and linux. Note that some of the existing implementations didn't all agree on what the tests should report! I don't remember if I looked at the POSIX spec or not.
So, I don't know how useful it will be - if nothing else, there are some tests! :-D
HTH
Ramsay Jones
Show 69 quoted lines
>
> Since `dirname()` is a sibling of `basename()`, we simply put our very
> own `gitdirname()` implementation next to `gitbasename()` and use it
> if `NO_LIBGEN_H` has been set.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>
> I stumbled over the compile warning when upgrading Git for Windows
> to 2.6.0. There was a left-over NO_LIBGEN_H=YesPlease (which we
> no longer need in Git for Windows 2.x), but it did point to the
> fact that we use `dirname()` in builtin/am.c now, so we better
> have a fall-back implementation for platforms without libgen.h.
>
> I tested this implementation a bit, but I still would appreciate
> a few eye-balls to go over it.
>
> compat/basename.c | 26 ++++++++++++++++++++++++++
> git-compat-util.h | 2 ++
> 2 files changed, 28 insertions(+)
>
> diff --git a/compat/basename.c b/compat/basename.c
> index d8f8a3c..10dba38 100644
> --- a/compat/basename.c
> +++ b/compat/basename.c
> @@ -13,3 +13,29 @@ char *gitbasename (char *path)
> }
> return (char *)base;
> }
> +
> +char *gitdirname(char *path)
> +{
> + char *p = path, *slash, c;
> +
> + /* Skip over the disk name in MSDOS pathnames. */
> + if (has_dos_drive_prefix(p))
> + p += 2;
> + /* POSIX.1-2001 says dirname("/") should return "/" */
> + slash = is_dir_sep(*p) ? ++p : NULL;
> + while ((c = *(p++)))
> + if (is_dir_sep(c)) {
> + char *tentative = p - 1;
> +
> + /* POSIX.1-2001 says to ignore trailing slashes */
> + while (is_dir_sep(*p))
> + p++;
> + if (*p)
> + slash = tentative;
> + }
> +
> + if (!slash)
> + return ".";
> + *slash = '\0';
> + return path;
> +}
> diff --git a/git-compat-util.h b/git-compat-util.h
> index f649e81..8b01aa5 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -253,6 +253,8 @@ struct itimerval {
> #else
> #define basename gitbasename
> extern char *gitbasename(char *);
> +#define dirname gitdirname
> +extern char *gitdirname(char *);
> #endif
>
> #ifndef NO_ICONV
> #include <stdio.h> #include <string.h> #include <ctype.h> #ifndef NO_LIBGEN_H # include <libgen.h> #endif
struct test_data {
char *from; /* input: transform from this ... */
char *to; /* output: ... to this. */
};#ifdef NO_LIBGEN_H
#if defined(__MINGW32__) || defined(_MSC_VER) #define has_dos_drive_prefix(path) (isalpha(*(path)) && (path)[1] == ':') #define is_dir_sep(c) ((c) == '/' || (c) == '\\') #else #define has_dos_drive_prefix(path) 0 #define is_dir_sep(c) ((c) == '/') #endif
#define basename gitbasename #define dirname gitdirname
char *gitbasename (char *path)
{
char *p; if (!path || !*path)
return ".";
/* skip drive designator, if any */
if (has_dos_drive_prefix(path))
path += 2;
if (!*path)
return ".";
/* trim trailing directory separators */
p = path + strlen(path) - 1;
while (is_dir_sep(*p)) {
if (p == path)
return path;
*p-- = '\0';
}
/* find begining of last path component */
while (p >= path && !is_dir_sep(*p))
p--;
return p + 1;
}char *gitdirname(char *path)
{
char *p, *start; if (!path || !*path)
return ".";
start = path;
/* skip drive designator, if any */
if (has_dos_drive_prefix(path))
start += 2;
/* check for // */
if (strcmp(start, "//") == 0)
return path;
/* check for \\ */
if (is_dir_sep('\\') && strcmp(start, "\\\\") == 0)
return path;
/* trim trailing directory separators */
p = path + strlen(path) - 1;
while (is_dir_sep(*p)) {
if (p == start)
return path;
*p-- = '\0';
}
/* find begining of last path component */
while (p >= start && !is_dir_sep(*p))
p--;
/* terminate dirname */
if (p < start) {
p = start;
*p++ = '.';
} else if (p == start)
p++;
*p = '\0';
return path;
}#endif
static int test_basename(void)
{
static struct test_data t[] = { /* --- POSIX type paths --- */
{ NULL, "." },
{ "", "." },
{ ".", "." },
{ "..", ".." },
{ "/", "/" },
#if defined(__CYGWIN__) && !defined(NO_LIBGEN_H)
{ "//", "//" },
{ "///", "//" },
{ "////", "//" },
#else
{ "//", "/" },
{ "///", "/" },
{ "////", "/" },
#endif
{ "usr", "usr" },
{ "/usr", "usr" },
{ "/usr/", "usr" },
{ "/usr//", "usr" },
{ "/usr/lib", "lib" },
{ "usr/lib", "lib" },
{ "usr/lib///", "lib" },#if defined(__MINGW32__) || defined(_MSC_VER)
/* --- win32 type paths --- */
{ "\\usr", "usr" },
{ "\\usr\\", "usr" },
{ "\\usr\\\\", "usr" },
{ "\\usr\\lib", "lib" },
{ "usr\\lib", "lib" },
{ "usr\\lib\\\\\\", "lib" },
{ "C:/usr", "usr" },
{ "C:/usr", "usr" },
{ "C:/usr/", "usr" },
{ "C:/usr//", "usr" },
{ "C:/usr/lib", "lib" },
{ "C:usr/lib", "lib" },
{ "C:usr/lib///", "lib" },
{ "C:", "." },
{ "C:a", "a" },
{ "C:/", "/" },
{ "C:///", "/" },
#if defined(NO_LIBGEN_H)
{ "\\", "\\" },
{ "\\\\", "\\" },
{ "\\\\\\", "\\" },
#else /* win32 platform variations: */
#if defined(__MINGW32__)
{ "\\", "/" },
{ "\\\\", "/" },
{ "\\\\\\", "/" },
#endif#if defined(_MSC_VER)
{ "\\", "\\" },
{ "\\\\", "\\" },
{ "\\\\\\", "\\" },
#endif#endif
#endif
{ NULL, "." }
};
static char input[1024];
char *from, *to;
int i, failed = 0; for (i = 0; i < sizeof(t)/sizeof(t[0]); i++) {
from = NULL;
if (t[i].from) {
strcpy(input, t[i].from);
from = input;
}
to = basename(from);
if (strcmp(to, t[i].to) != 0) {
fprintf(stderr, "FAIL: basename(%s) => '%s' != '%s'\n",
t[i].from, to, t[i].to);
failed++;
}
}
return failed != 0;
}static int test_dirname(void)
{
static struct test_data t[] = { /* --- POSIX type paths --- */
{ NULL, "." },
{ "", "." },
{ ".", "." },
{ "..", "." },
{ "/", "/" },
{ "//", "//" },
#if defined(__CYGWIN__) && !defined(NO_LIBGEN_H)
{ "///", "//" },
{ "////", "//" },
#else
{ "///", "/" },
{ "////", "/" },
#endif
{ "usr", "." },
{ "/usr", "/" },
{ "/usr/", "/" },
{ "/usr//", "/" },
{ "/usr/lib", "/usr" },
{ "usr/lib", "usr" },
{ "usr/lib///", "usr" },#if defined(__MINGW32__) || defined(_MSC_VER)
/* --- win32 type paths --- */
{ "\\", "\\" },
{ "\\\\", "\\\\" },
{ "\\usr", "\\" },
{ "\\usr\\", "\\" },
{ "\\usr\\\\", "\\" },
{ "\\usr\\lib", "\\usr" },
{ "usr\\lib", "usr" },
{ "usr\\lib\\\\\\", "usr" },
{ "C:a", "C:." },
{ "C:/", "C:/" },
{ "C:///", "C:/" },
{ "C:/usr", "C:/" },
{ "C:/usr/", "C:/" },
{ "C:/usr//", "C:/" },
{ "C:/usr/lib", "C:/usr" },
{ "C:usr/lib", "C:usr" },
{ "C:usr/lib///", "C:usr" },
{ "\\\\\\", "\\" },
{ "\\\\\\\\", "\\" },
#if defined(NO_LIBGEN_H)
{ "C:", "C:." },
#else /* win32 platform variations: */
#if defined(__MINGW32__)
/* the following is clearly wrong ... */
{ "C:", "." },
#endif#if defined(_MSC_VER)
{ "C:", "C:." },
#endif#endif
#endif
{ NULL, "." }
};
static char input[1024];
char *from, *to;
int i, failed = 0; for (i = 0; i < sizeof(t)/sizeof(t[0]); i++) {
from = NULL;
if (t[i].from) {
strcpy(input, t[i].from);
from = input;
}
to = dirname(from);
if (strcmp(to, t[i].to) != 0) {
fprintf(stderr, "FAIL: dirname(%s) => '%s' != '%s'\n",
t[i].from, to, t[i].to);
failed++;
}
}
return failed != 0;
}int main(int argc, char **argv)
{
if (argc == 2 && !strcmp(argv[1], "basename"))
return test_basename();if (argc == 2 && !strcmp(argv[1], "dirname")) return test_dirname();
fprintf(stderr, "%s: unknown function name: %s\n", argv[0], argv[1] ? argv[1] : "(there was none)"); return 1; }