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Attached patch gets rid of the global timezone in the following steps:

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* Changes the APIs to the timezone functions to take a pg_tz pointer as
an argument, representing the timezone to use for the selected
operation.

* Adds a global_timezone variable that represents the current timezone
in the backend as set by SET TIMEZONE (or guc, or env, etc).

* Implements a hash-table cache of loaded tables, so we don't have to
read and parse the TZ file everytime we change a timezone. While not
necesasry now (we don't change timezones very often), I beleive this
will be necessary (or at least good) when "multiple timezones in the
same query" is eventually implemented. And code-wise, this was the time
to do it.


There are no user-visible changes at this time. Implementing the
"multiple zones in one query" is a later step...

This also gets rid of some of the cruft needed to "back out a timezone
change", since we previously couldn't check a timezone unless it was
activated first.

Passes regression tests on win32, linux (slackware 10) and solaris x86.

Magnus Hagander
This commit is contained in:
Bruce Momjian
2005-04-19 03:13:59 +00:00
parent dd39dd232f
commit aa8bdab272
11 changed files with 234 additions and 192 deletions
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99
src/timezone/localtime.c
View File

@@ -3,7 +3,7 @@
* 1996-06-05 by Arthur David Olson (arthur_david_olson@nih.gov).
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/timezone/localtime.c,v 1.9 2004/11/01 21:34:44 tgl Exp $
* $PostgreSQL: pgsql/src/timezone/localtime.c,v 1.10 2005/04/19 03:13:59 momjian Exp $
*/
/*
@@ -16,8 +16,8 @@
#include <fcntl.h>
#include "pgtz.h"
#include "private.h"
#include "pgtz.h"
#include "tzfile.h"
@@ -58,37 +58,6 @@ static const char gmt[] = "GMT";
*/
#define TZDEFRULESTRING ",M4.1.0,M10.5.0"
struct ttinfo
{ /* time type information */
long tt_gmtoff; /* UTC offset in seconds */
int tt_isdst; /* used to set tm_isdst */
int tt_abbrind; /* abbreviation list index */
int tt_ttisstd; /* TRUE if transition is std time */
int tt_ttisgmt; /* TRUE if transition is UTC */
};
struct lsinfo
{ /* leap second information */
pg_time_t ls_trans; /* transition time */
long ls_corr; /* correction to apply */
};
#define BIGGEST(a, b) (((a) > (b)) ? (a) : (b))
struct state
{
int leapcnt;
int timecnt;
int typecnt;
int charcnt;
pg_time_t ats[TZ_MAX_TIMES];
unsigned char types[TZ_MAX_TIMES];
struct ttinfo ttis[TZ_MAX_TYPES];
char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
(2 * (TZ_STRLEN_MAX + 1)))];
struct lsinfo lsis[TZ_MAX_LEAPS];
};
struct rule
{
int r_type; /* type of rule--see below */
@@ -115,22 +84,19 @@ static const char *getoffset(const char *strp, long *offsetp);
static const char *getrule(const char *strp, struct rule * rulep);
static void gmtload(struct state * sp);
static void gmtsub(const pg_time_t *timep, long offset, struct pg_tm * tmp);
static void localsub(const pg_time_t *timep, long offset, struct pg_tm * tmp);
static void localsub(const pg_time_t *timep, long offset, struct pg_tm * tmp, const pg_tz *tz);
static void timesub(const pg_time_t *timep, long offset,
const struct state * sp, struct pg_tm * tmp);
static pg_time_t transtime(pg_time_t janfirst, int year,
const struct rule * rulep, long offset);
static int tzload(const char *name, struct state * sp);
static int tzparse(const char *name, struct state * sp, int lastditch);
const struct rule * rulep, long offset);
int tzparse(const char *name, struct state * sp, int lastditch);
static struct state lclmem;
/* GMT timezone */
static struct state gmtmem;
#define lclptr (&lclmem)
#define gmtptr (&gmtmem)
static char lcl_TZname[TZ_STRLEN_MAX + 1];
static int lcl_is_set = 0;
static int gmt_is_set = 0;
/*
@@ -156,7 +122,7 @@ detzcode(const char *codep)
return result;
}
static int
int
tzload(register const char *name, register struct state * sp)
{
register const char *p;
@@ -589,7 +555,7 @@ transtime(const pg_time_t janfirst, const int year,
* appropriate.
*/
static int
int
tzparse(const char *name, register struct state * sp, const int lastditch)
{
const char *stdname;
@@ -839,30 +805,6 @@ gmtload(struct state * sp)
}
bool
pg_tzset(const char *name)
{
if (lcl_is_set && strcmp(lcl_TZname, name) == 0)
return true; /* no change */
if (strlen(name) >= sizeof(lcl_TZname))
return false; /* not gonna fit */
if (tzload(name, lclptr) != 0)
{
if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
{
/* Unknown timezone. Fail our call instead of loading GMT! */
return false;
}
}
strcpy(lcl_TZname, name);
lcl_is_set = true;
return true;
}
/*
* The easy way to behave "as if no library function calls" localtime
* is to not call it--so we drop its guts into "localsub", which can be
@@ -872,14 +814,14 @@ pg_tzset(const char *name)
* The unused offset argument is for the benefit of mktime variants.
*/
static void
localsub(const pg_time_t *timep, const long offset, struct pg_tm * tmp)
localsub(const pg_time_t *timep, const long offset, struct pg_tm * tmp, const pg_tz *tz)
{
register struct state *sp;
register const struct state *sp;
register const struct ttinfo *ttisp;
register int i;
const pg_time_t t = *timep;
sp = lclptr;
sp = &tz->state;
if (sp->timecnt == 0 || t < sp->ats[0])
{
i = 0;
@@ -906,9 +848,9 @@ localsub(const pg_time_t *timep, const long offset, struct pg_tm * tmp)
struct pg_tm *
pg_localtime(const pg_time_t *timep)
pg_localtime(const pg_time_t *timep, const pg_tz *tz)
{
localsub(timep, 0L, &tm);
localsub(timep, 0L, &tm, tz);
return &tm;
}
@@ -1084,15 +1026,16 @@ pg_next_dst_boundary(const pg_time_t *timep,
int *before_isdst,
pg_time_t *boundary,
long int *after_gmtoff,
int *after_isdst)
int *after_isdst,
const pg_tz *tz)
{
register struct state *sp;
register const struct state *sp;
register const struct ttinfo *ttisp;
int i;
int j;
const pg_time_t t = *timep;
sp = lclptr;
sp = &tz->state;
if (sp->timecnt == 0)
{
/* non-DST zone, use lowest-numbered standard type */
@@ -1158,9 +1101,9 @@ pg_next_dst_boundary(const pg_time_t *timep,
* Return the name of the current timezone
*/
const char *
pg_get_current_timezone(void)
pg_get_timezone_name(pg_tz *tz)
{
if (lcl_is_set)
return lcl_TZname;
if (tz)
return tz->TZname;
return NULL;
}