spi.c

关系型数据库 Postgresql 6.5.2

/*-------------------------------------------------------------------------
 *
 * spi.c
 *				Server Programming Interface
 *
 * $Id: spi.c,v 1.39 1999/05/25 22:41:02 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "executor/spi.h"
#include "executor/spi_priv.h"
#include "catalog/pg_type.h"
#include "access/printtup.h"
#include "fmgr.h"

static Portal _SPI_portal = (Portal) NULL;
static _SPI_connection *_SPI_stack = NULL;
static _SPI_connection *_SPI_current = NULL;
static int	_SPI_connected = -1;
static int	_SPI_curid = -1;

DLLIMPORT uint32 SPI_processed = 0;
DLLIMPORT SPITupleTable *SPI_tuptable;
DLLIMPORT int SPI_result;

static int	_SPI_execute(char *src, int tcount, _SPI_plan *plan);
static int	_SPI_pquery(QueryDesc *queryDesc, EState *state, int tcount);

static int _SPI_execute_plan(_SPI_plan *plan,
				  Datum *Values, char *Nulls, int tcount);

static _SPI_plan *_SPI_copy_plan(_SPI_plan *plan, int location);

static int	_SPI_begin_call(bool execmem);
static int	_SPI_end_call(bool procmem);
static MemoryContext _SPI_execmem(void);
static MemoryContext _SPI_procmem(void);
static bool _SPI_checktuples(void);

#ifdef SPI_EXECUTOR_STATS
extern int	ShowExecutorStats;
extern void ResetUsage(void);
extern void ShowUsage(void);

#endif

/* =================== interface functions =================== */

int
SPI_connect()
{
	char		pname[64];
	PortalVariableMemory pvmem;

	/*
	 * It's possible on startup and after commit/abort. In future we'll
	 * catch commit/abort in some way...
	 */
	strcpy(pname, "<SPI manager>");
	_SPI_portal = GetPortalByName(pname);
	if (!PortalIsValid(_SPI_portal))
	{
		if (_SPI_stack != NULL) /* there was abort */
			free(_SPI_stack);
		_SPI_current = _SPI_stack = NULL;
		_SPI_connected = _SPI_curid = -1;
		SPI_processed = 0;
		SPI_tuptable = NULL;
		_SPI_portal = CreatePortal(pname);
		if (!PortalIsValid(_SPI_portal))
			elog(FATAL, "SPI_connect: global initialization failed");
	}

	/*
	 * When procedure called by Executor _SPI_curid expected to be equal
	 * to _SPI_connected
	 */
	if (_SPI_curid != _SPI_connected)
		return SPI_ERROR_CONNECT;

	if (_SPI_stack == NULL)
	{
		if (_SPI_connected != -1)
			elog(FATAL, "SPI_connect: no connection(s) expected");
		_SPI_stack = (_SPI_connection *) malloc(sizeof(_SPI_connection));
	}
	else
	{
		if (_SPI_connected <= -1)
			elog(FATAL, "SPI_connect: some connection(s) expected");
		_SPI_stack = (_SPI_connection *) realloc(_SPI_stack,
						 (_SPI_connected + 2) * sizeof(_SPI_connection));
	}

	/*
	 * We' returning to procedure where _SPI_curid == _SPI_connected - 1
	 */
	_SPI_connected++;

	_SPI_current = &(_SPI_stack[_SPI_connected]);
	_SPI_current->qtlist = NULL;
	_SPI_current->processed = 0;
	_SPI_current->tuptable = NULL;

	/* Create Portal for this procedure ... */
	snprintf(pname, 64, "<SPI %d>", _SPI_connected);
	_SPI_current->portal = CreatePortal(pname);
	if (!PortalIsValid(_SPI_current->portal))
		elog(FATAL, "SPI_connect: initialization failed");

	/* ... and switch to Portal' Variable memory - procedure' context */
	pvmem = PortalGetVariableMemory(_SPI_current->portal);
	_SPI_current->savedcxt = MemoryContextSwitchTo((MemoryContext) pvmem);

	_SPI_current->savedId = GetScanCommandId();
	SetScanCommandId(GetCurrentCommandId());

	return SPI_OK_CONNECT;

}

int
SPI_finish()
{
	int			res;

	res = _SPI_begin_call(false);		/* live in procedure memory */
	if (res < 0)
		return res;

	/* Restore memory context as it was before procedure call */
	MemoryContextSwitchTo(_SPI_current->savedcxt);
	PortalDestroy(&(_SPI_current->portal));

	SetScanCommandId(_SPI_current->savedId);

	/*
	 * After _SPI_begin_call _SPI_connected == _SPI_curid. Now we are
	 * closing connection to SPI and returning to upper Executor and so
	 * _SPI_connected must be equal to _SPI_curid.
	 */
	_SPI_connected--;
	_SPI_curid--;
	if (_SPI_connected == -1)
	{
		free(_SPI_stack);
		_SPI_stack = NULL;
	}
	else
	{
		_SPI_stack = (_SPI_connection *) realloc(_SPI_stack,
						 (_SPI_connected + 1) * sizeof(_SPI_connection));
		_SPI_current = &(_SPI_stack[_SPI_connected]);
	}

	return SPI_OK_FINISH;

}

void
SPI_push(void)
{
	_SPI_curid++;
}

void
SPI_pop(void)
{
	_SPI_curid--;
}

int
SPI_exec(char *src, int tcount)
{
	int			res;

	if (src == NULL || tcount < 0)
		return SPI_ERROR_ARGUMENT;

	res = _SPI_begin_call(true);
	if (res < 0)
		return res;

	res = _SPI_execute(src, tcount, NULL);

	_SPI_end_call(true);
	return res;
}

int
SPI_execp(void *plan, Datum *Values, char *Nulls, int tcount)
{
	int			res;

	if (plan == NULL || tcount < 0)
		return SPI_ERROR_ARGUMENT;

	if (((_SPI_plan *) plan)->nargs > 0 && Values == NULL)
		return SPI_ERROR_PARAM;

	res = _SPI_begin_call(true);
	if (res < 0)
		return res;

	/* copy plan to current (executor) context */
	plan = (void *) _SPI_copy_plan(plan, _SPI_CPLAN_CURCXT);

	res = _SPI_execute_plan((_SPI_plan *) plan, Values, Nulls, tcount);

	_SPI_end_call(true);
	return res;
}

void *
SPI_prepare(char *src, int nargs, Oid *argtypes)
{
	_SPI_plan  *plan;

	if (src == NULL || nargs < 0 || (nargs > 0 && argtypes == NULL))
	{
		SPI_result = SPI_ERROR_ARGUMENT;
		return NULL;
	}

	SPI_result = _SPI_begin_call(true);
	if (SPI_result < 0)
		return NULL;

	plan = (_SPI_plan *) palloc(sizeof(_SPI_plan));		/* Executor context */
	plan->argtypes = argtypes;
	plan->nargs = nargs;

	SPI_result = _SPI_execute(src, 0, plan);

	if (SPI_result >= 0)		/* copy plan to procedure context */
		plan = _SPI_copy_plan(plan, _SPI_CPLAN_PROCXT);
	else
		plan = NULL;

	_SPI_end_call(true);

	return (void *) plan;

}

void *
SPI_saveplan(void *plan)
{
	_SPI_plan  *newplan;

	if (plan == NULL)
	{
		SPI_result = SPI_ERROR_ARGUMENT;
		return NULL;
	}

	SPI_result = _SPI_begin_call(false);		/* don't change context */
	if (SPI_result < 0)
		return NULL;

	newplan = _SPI_copy_plan((_SPI_plan *) plan, _SPI_CPLAN_TOPCXT);

	_SPI_curid--;
	SPI_result = 0;

	return (void *) newplan;

}

HeapTuple
SPI_copytuple(HeapTuple tuple)
{
	MemoryContext oldcxt = NULL;
	HeapTuple	ctuple;

	if (tuple == NULL)
	{
		SPI_result = SPI_ERROR_ARGUMENT;
		return NULL;
	}

	if (_SPI_curid + 1 == _SPI_connected)		/* connected */
	{
		if (_SPI_current != &(_SPI_stack[_SPI_curid + 1]))
			elog(FATAL, "SPI: stack corrupted");
		oldcxt = MemoryContextSwitchTo(_SPI_current->savedcxt);
	}

	ctuple = heap_copytuple(tuple);

	if (oldcxt)
		MemoryContextSwitchTo(oldcxt);

	return ctuple;
}

HeapTuple
SPI_modifytuple(Relation rel, HeapTuple tuple, int natts, int *attnum,
				Datum *Values, char *Nulls)
{
	MemoryContext oldcxt = NULL;
	HeapTuple	mtuple;
	int			numberOfAttributes;
	uint8		infomask;
	Datum	   *v;
	char	   *n;
	bool		isnull;
	int			i;

	if (rel == NULL || tuple == NULL || natts <= 0 || attnum == NULL || Values == NULL)
	{
		SPI_result = SPI_ERROR_ARGUMENT;
		return NULL;
	}

	if (_SPI_curid + 1 == _SPI_connected)		/* connected */
	{
		if (_SPI_current != &(_SPI_stack[_SPI_curid + 1]))
			elog(FATAL, "SPI: stack corrupted");
		oldcxt = MemoryContextSwitchTo(_SPI_current->savedcxt);
	}
	SPI_result = 0;
	numberOfAttributes = rel->rd_att->natts;
	v = (Datum *) palloc(numberOfAttributes * sizeof(Datum));
	n = (char *) palloc(numberOfAttributes * sizeof(char));

	/* fetch old values and nulls */
	for (i = 0; i < numberOfAttributes; i++)
	{
		v[i] = heap_getattr(tuple, i + 1, rel->rd_att, &isnull);
		n[i] = (isnull) ? 'n' : ' ';
	}

	/* replace values and nulls */
	for (i = 0; i < natts; i++)
	{
		if (attnum[i] <= 0 || attnum[i] > numberOfAttributes)
			break;
		v[attnum[i] - 1] = Values[i];
		n[attnum[i] - 1] = (Nulls && Nulls[i] == 'n') ? 'n' : ' ';
	}

	if (i == natts)				/* no errors in *attnum */
	{
		mtuple = heap_formtuple(rel->rd_att, v, n);
		infomask = mtuple->t_data->t_infomask;
		memmove(&(mtuple->t_data->t_oid), &(tuple->t_data->t_oid),
				((char *) &(tuple->t_data->t_hoff) -
				 (char *) &(tuple->t_data->t_oid)));
		mtuple->t_data->t_infomask = infomask;
		mtuple->t_data->t_natts = numberOfAttributes;
	}
	else
	{
		mtuple = NULL;
		SPI_result = SPI_ERROR_NOATTRIBUTE;
	}

	pfree(v);
	pfree(n);

	if (oldcxt)
		MemoryContextSwitchTo(oldcxt);

	return mtuple;
}

int
SPI_fnumber(TupleDesc tupdesc, char *fname)
{
	int			res;

	for (res = 0; res < tupdesc->natts; res++)
	{
		if (strcasecmp(tupdesc->attrs[res]->attname.data, fname) == 0)
			return res + 1;
	}

	return SPI_ERROR_NOATTRIBUTE;
}

char *
SPI_fname(TupleDesc tupdesc, int fnumber)
{

	SPI_result = 0;
	if (tupdesc->natts < fnumber || fnumber <= 0)
	{
		SPI_result = SPI_ERROR_NOATTRIBUTE;
		return NULL;
	}

	return nameout(&(tupdesc->attrs[fnumber - 1]->attname));
}

char *
SPI_getvalue(HeapTuple tuple, TupleDesc tupdesc, int fnumber)
{
	Datum		val;
	bool		isnull;
	Oid			foutoid,
				typelem;

	SPI_result = 0;
	if (tuple->t_data->t_natts < fnumber || fnumber <= 0)
	{
		SPI_result = SPI_ERROR_NOATTRIBUTE;
		return NULL;
	}

	val = heap_getattr(tuple, fnumber, tupdesc, &isnull);
	if (isnull)
		return NULL;
	if (!getTypeOutAndElem((Oid) tupdesc->attrs[fnumber - 1]->atttypid,
						   &foutoid, &typelem))
	{
		SPI_result = SPI_ERROR_NOOUTFUNC;
		return NULL;
	}

	return (fmgr(foutoid, val, typelem,
				 tupdesc->attrs[fnumber - 1]->atttypmod));
}

Datum
SPI_getbinval(HeapTuple tuple, TupleDesc tupdesc, int fnumber, bool *isnull)
{
	Datum		val;

	*isnull = true;
	SPI_result = 0;
	if (tuple->t_data->t_natts < fnumber || fnumber <= 0)
	{
		SPI_result = SPI_ERROR_NOATTRIBUTE;
		return (Datum) NULL;
	}

	val = heap_getattr(tuple, fnumber, tupdesc, isnull);

	return val;
}

char *
SPI_gettype(TupleDesc tupdesc, int fnumber)
{
	HeapTuple	typeTuple;

	SPI_result = 0;
	if (tupdesc->natts < fnumber || fnumber <= 0)
	{
		SPI_result = SPI_ERROR_NOATTRIBUTE;
		return NULL;
	}

	typeTuple = SearchSysCacheTuple(TYPOID,
				 ObjectIdGetDatum(tupdesc->attrs[fnumber - 1]->atttypid),
									0, 0, 0);

	if (!HeapTupleIsValid(typeTuple))
	{
		SPI_result = SPI_ERROR_TYPUNKNOWN;
		return NULL;
	}

	return pstrdup(((Form_pg_type) GETSTRUCT(typeTuple))->typname.data);
}

Oid
SPI_gettypeid(TupleDesc tupdesc, int fnumber)
{

	SPI_result = 0;
	if (tupdesc->natts < fnumber || fnumber <= 0)
	{
		SPI_result = SPI_ERROR_NOATTRIBUTE;
		return InvalidOid;
	}

	return tupdesc->attrs[fnumber - 1]->atttypid;
}

char *
SPI_getrelname(Relation rel)
{
	return pstrdup(rel->rd_rel->relname.data);
}

void *
SPI_palloc(Size size)
{
	MemoryContext oldcxt = NULL;
	void	   *pointer;

	if (_SPI_curid + 1 == _SPI_connected)		/* connected */
	{
		if (_SPI_current != &(_SPI_stack[_SPI_curid + 1]))
			elog(FATAL, "SPI: stack corrupted");
		oldcxt = MemoryContextSwitchTo(_SPI_current->savedcxt);
	}

	pointer = palloc(size);

	if (oldcxt)
		MemoryContextSwitchTo(oldcxt);

	return pointer;
}

void *
SPI_repalloc(void *pointer, Size size)
{