Re: [PATCH] Add a new lstat and fstat implementation based on Win32 API

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Sep 4, 2007, 12:46 UTC
Message-ID: <Pine.LNX.4.64.0709041324420.28586@racer.site>
In-Reply-To: <46DD433A.5040604@eudaptics.com>

Hi,

On Tue, 4 Sep 2007, Johannes Sixt wrote:

Show 12 quoted lines

> Johannes Schindelin schrieb:
> > On Tue, 4 Sep 2007, Johannes Sixt wrote:
> > > Therefore, I've pushed out a fixup patch at the top of mingw.git's devel
> > > branch that converts mtime to local time
> > 
> > On Linux, we compare to UTC to begin with, right?  We should do that here,
> > too...  So if time(NULL) does not return UTC on MinGW, we have to wrap that
> > function, too.
> 
> According to MSDN, time(NULL) returns "the number of seconds elapsed since
> [epoch] according to the system clock". Please don't ask me what "the system
> clock" is.

I think I know. From my QEmu adventures I know that DOS/Windows expects the system clock to be set to local time, in contrast to _all_ other operating systems.

Show 6 quoted lines

> Reading the implementation of time(), it starts with GetLocalTime(), 
> determines whether daylight saving is in effect, and continues with 
> another round of timezone adjustment - mind you: _not_ a timezone 
> reversal (!!). Doesn't this look extremely bogus?
> 
> It seems we really need a wrapper for time().

I absolutely concur. Something like this (most of it is blatantly copied from Marius' patch)?

-- snip --

diff --git a/git-compat-util.h b/git-compat-util.h
index 172e828..2984319 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -470,6 +470,17 @@ static inline int git_unlink(const char *pathname) 
{
 #include <time.h>
 struct tm *gmtime_r(const time_t *timep, struct tm *result);
 struct tm *localtime_r(const time_t *timep, struct tm *result);
+static inline time_t mingw_time(void *dummy)
+{
+	FILETIME ft;
+	GetSystemTimeAsFileTime(&ft);
+	long long winTime = ((long long)ft.dwHighDateTime << 32) + 
ft.dwLowDateTime;
+	winTime -= 116444736000000000LL; /* Windows to Unix Epoch 
conversion */
+	winTime /= 10000000;		 /* Nano to seconds resolution 
*/
+	return (time_t)winTime;
+
+}
+#define time mingw_time
 #define hstrerror strerror
 
 char *mingw_getcwd(char *pointer, int len);
-- snap --

Ciao,
Dscho