pgtclid.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 863 行 · 第 1/2 页

/*-------------------------------------------------------------------------
 *
 * pgtclId.c
 *
 *	Contains Tcl "channel" interface routines, plus useful routines
 *	to convert between strings and pointers.  These are needed because
 *	everything in Tcl is a string, but in C, pointers to data structures
 *	are needed.
 *
 *	ASSUMPTION:  sizeof(long) >= sizeof(void*)
 *
 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/interfaces/libpgtcl/Attic/pgtclId.c,v 1.43 2003/08/04 02:40:16 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres_fe.h"

#include <errno.h>

#include "pgtclCmds.h"
#include "pgtclId.h"


static int
PgEndCopy(Pg_ConnectionId * connid, int *errorCodePtr)
{
	connid->res_copyStatus = RES_COPY_NONE;
	if (PQendcopy(connid->conn))
	{
		PQclear(connid->results[connid->res_copy]);
		connid->results[connid->res_copy] =
			PQmakeEmptyPGresult(connid->conn, PGRES_BAD_RESPONSE);
		connid->res_copy = -1;
		*errorCodePtr = EIO;
		return -1;
	}
	else
	{
		PQclear(connid->results[connid->res_copy]);
		connid->results[connid->res_copy] =
			PQmakeEmptyPGresult(connid->conn, PGRES_COMMAND_OK);
		connid->res_copy = -1;
		return 0;
	}
}

/*
 *	Called when reading data (via gets) for a copy <rel> to stdout.
 */
int
PgInputProc(DRIVER_INPUT_PROTO)
{
	Pg_ConnectionId *connid;
	PGconn	   *conn;
	int			avail;

	connid = (Pg_ConnectionId *) cData;
	conn = connid->conn;

	if (connid->res_copy < 0 ||
	 PQresultStatus(connid->results[connid->res_copy]) != PGRES_COPY_OUT)
	{
		*errorCodePtr = EBUSY;
		return -1;
	}

	/*
	 * Read any newly arrived data into libpq's buffer, thereby clearing
	 * the socket's read-ready condition.
	 */
	if (!PQconsumeInput(conn))
	{
		*errorCodePtr = EIO;
		return -1;
	}

	/* Move data from libpq's buffer to Tcl's. */

	avail = PQgetlineAsync(conn, buf, bufSize);

	if (avail < 0)
	{
		/* Endmarker detected, change state and return 0 */
		return PgEndCopy(connid, errorCodePtr);
	}

	return avail;
}

/*
 *	Called when writing data (via puts) for a copy <rel> from stdin
 */
int
PgOutputProc(DRIVER_OUTPUT_PROTO)
{
	Pg_ConnectionId *connid;
	PGconn	   *conn;

	connid = (Pg_ConnectionId *) cData;
	conn = connid->conn;

	if (connid->res_copy < 0 ||
	  PQresultStatus(connid->results[connid->res_copy]) != PGRES_COPY_IN)
	{
		*errorCodePtr = EBUSY;
		return -1;
	}

	if (PQputnbytes(conn, buf, bufSize))
	{
		*errorCodePtr = EIO;
		return -1;
	}

	/*
	 * This assumes Tcl script will write the terminator line in a single
	 * operation; maybe not such a good assumption?
	 */
	if (bufSize >= 3 && strncmp(&buf[bufSize - 3], "\\.\n", 3) == 0)
	{
		if (PgEndCopy(connid, errorCodePtr) == -1)
			return -1;
	}
	return bufSize;
}

#if HAVE_TCL_GETFILEPROC

Tcl_File
PgGetFileProc(ClientData cData, int direction)
{
	return (Tcl_File) NULL;
}
#endif

/*
 * The WatchProc and GetHandleProc are no-ops but must be present.
 */
static void
PgWatchProc(ClientData instanceData, int mask)
{
}

static int
PgGetHandleProc(ClientData instanceData, int direction,
				ClientData *handlePtr)
{
	return TCL_ERROR;
}

Tcl_ChannelType Pg_ConnType = {
	"pgsql",					/* channel type */
	NULL,						/* blockmodeproc */
	PgDelConnectionId,			/* closeproc */
	PgInputProc,				/* inputproc */
	PgOutputProc,				/* outputproc */
	NULL,						/* SeekProc, Not used */
	NULL,						/* SetOptionProc, Not used */
	NULL,						/* GetOptionProc, Not used */
	PgWatchProc,				/* WatchProc, must be defined */
	PgGetHandleProc,			/* GetHandleProc, must be defined */
	NULL						/* Close2Proc, Not used */
};

/*
 * Create and register a new channel for the connection
 */
void
PgSetConnectionId(Tcl_Interp *interp, PGconn *conn)
{
	Tcl_Channel conn_chan;
	Pg_ConnectionId *connid;
	int			i;

	connid = (Pg_ConnectionId *) ckalloc(sizeof(Pg_ConnectionId));
	connid->conn = conn;
	connid->res_count = 0;
	connid->res_last = -1;
	connid->res_max = RES_START;
	connid->res_hardmax = RES_HARD_MAX;
	connid->res_copy = -1;
	connid->res_copyStatus = RES_COPY_NONE;
	connid->results = (PGresult **) ckalloc(sizeof(PGresult *) * RES_START);
	for (i = 0; i < RES_START; i++)
		connid->results[i] = NULL;
	connid->notify_list = NULL;
	connid->notifier_running = 0;

	sprintf(connid->id, "pgsql%d", PQsocket(conn));

#if TCL_MAJOR_VERSION >= 8
	connid->notifier_channel = Tcl_MakeTcpClientChannel((ClientData) PQsocket(conn));
	Tcl_RegisterChannel(NULL, connid->notifier_channel);
#else
	connid->notifier_socket = -1;
#endif

#if TCL_MAJOR_VERSION == 7 && TCL_MINOR_VERSION == 5
	/* Original signature (only seen in Tcl 7.5) */
	conn_chan = Tcl_CreateChannel(&Pg_ConnType, connid->id, NULL, NULL, (ClientData) connid);
#else
	/* Tcl 7.6 and later use this */
	conn_chan = Tcl_CreateChannel(&Pg_ConnType, connid->id, (ClientData) connid,
								  TCL_READABLE | TCL_WRITABLE);
#endif

	Tcl_SetChannelOption(interp, conn_chan, "-buffering", "line");
	Tcl_SetResult(interp, connid->id, TCL_VOLATILE);
	Tcl_RegisterChannel(interp, conn_chan);
}


/*
 * Get back the connection from the Id
 */
PGconn *
PgGetConnectionId(Tcl_Interp *interp, CONST84 char *id,
				  Pg_ConnectionId ** connid_p)
{
	Tcl_Channel conn_chan;
	Pg_ConnectionId *connid;

	conn_chan = Tcl_GetChannel(interp, id, 0);
	if (conn_chan == NULL || Tcl_GetChannelType(conn_chan) != &Pg_ConnType)
	{
		Tcl_ResetResult(interp);
		Tcl_AppendResult(interp, id, " is not a valid postgresql connection", 0);
		if (connid_p)
			*connid_p = NULL;
		return (PGconn *) NULL;
	}

	connid = (Pg_ConnectionId *) Tcl_GetChannelInstanceData(conn_chan);
	if (connid_p)
		*connid_p = connid;
	return connid->conn;
}


/*
 * Remove a connection Id from the hash table and
 * close all portals the user forgot.
 */
int
PgDelConnectionId(DRIVER_DEL_PROTO)
{
	Tcl_HashEntry *entry;
	Tcl_HashSearch hsearch;
	Pg_ConnectionId *connid;
	Pg_TclNotifies *notifies;
	int			i;

	connid = (Pg_ConnectionId *) cData;

	for (i = 0; i < connid->res_max; i++)
	{
		if (connid->results[i])
			PQclear(connid->results[i]);
	}
	ckfree((void *) connid->results);

	/* Release associated notify info */
	while ((notifies = connid->notify_list) != NULL)
	{
		connid->notify_list = notifies->next;
		for (entry = Tcl_FirstHashEntry(&notifies->notify_hash, &hsearch);
			 entry != NULL;
			 entry = Tcl_NextHashEntry(&hsearch))
			ckfree((char *) Tcl_GetHashValue(entry));
		Tcl_DeleteHashTable(&notifies->notify_hash);
		if (notifies->conn_loss_cmd)
			ckfree((void *) notifies->conn_loss_cmd);
		if (notifies->interp)
			Tcl_DontCallWhenDeleted(notifies->interp, PgNotifyInterpDelete,
									(ClientData) notifies);
		ckfree((void *) notifies);
	}

	/*
	 * Turn off the Tcl event source for this connection, and delete any
	 * pending notify and connection-loss events.
	 */
	PgStopNotifyEventSource(connid, true);

	/* Close the libpq connection too */
	PQfinish(connid->conn);
	connid->conn = NULL;

	/*
	 * Kill the notifier channel, too.	We must not do this until after
	 * we've closed the libpq connection, because Tcl will try to close
	 * the socket itself!
	 *
	 * XXX Unfortunately, while this works fine if we are closing due to
	 * explicit pg_disconnect, all Tcl versions through 8.4.1 dump core if
	 * we try to do it during interpreter shutdown.  Not clear why. For
	 * now, we kill the channel during pg_disconnect, but during interp
	 * shutdown we just accept leakage of the (fairly small) amount of
	 * memory taken for the channel state representation. (Note we are not
	 * leaking a socket, since libpq closed that already.) We tell the
	 * difference between pg_disconnect and interpreter shutdown by
	 * testing for interp != NULL, which is an undocumented but apparently
	 * safe way to tell.
	 */
#if TCL_MAJOR_VERSION >= 8
	if (connid->notifier_channel != NULL && interp != NULL)
		Tcl_UnregisterChannel(NULL, connid->notifier_channel);
#endif

	/*
	 * We must use Tcl_EventuallyFree because we don't want the connid
	 * struct to vanish instantly if Pg_Notify_EventProc is active for it.
	 * (Otherwise, closing the connection from inside a pg_listen callback
	 * could lead to coredump.)  Pg_Notify_EventProc can detect that the
	 * connection has been deleted from under it by checking connid->conn.
	 */
	Tcl_EventuallyFree((ClientData) connid, TCL_DYNAMIC);

	return 0;
}


/*
 * Find a slot for a new result id.  If the table is full, expand it by
 * a factor of 2.  However, do not expand past the hard max, as the client
 * is probably just not clearing result handles like they should.
 */
int
PgSetResultId(Tcl_Interp *interp, CONST84 char *connid_c, PGresult *res)
{
	Tcl_Channel conn_chan;
	Pg_ConnectionId *connid;
	int			resid,
				i;
	char		buf[32];


	conn_chan = Tcl_GetChannel(interp, connid_c, 0);
	if (conn_chan == NULL)
		return TCL_ERROR;
	connid = (Pg_ConnectionId *) Tcl_GetChannelInstanceData(conn_chan);

	/* search, starting at slot after the last one used */
	resid = connid->res_last;
	for (;;)
	{
		/* advance, with wraparound */
		if (++resid >= connid->res_max)
			resid = 0;
		/* this slot empty? */
		if (!connid->results[resid])
		{
			connid->res_last = resid;
			break;				/* success exit */
		}
		/* checked all slots? */
		if (resid == connid->res_last)
			break;				/* failure exit */
	}

	if (connid->results[resid])
	{
		/* no free slot found, so try to enlarge array */
		if (connid->res_max >= connid->res_hardmax)
		{
			Tcl_SetResult(interp, "hard limit on result handles reached",
						  TCL_STATIC);
			return TCL_ERROR;
		}
		connid->res_last = resid = connid->res_max;
		connid->res_max *= 2;
		if (connid->res_max > connid->res_hardmax)
			connid->res_max = connid->res_hardmax;
		connid->results = (PGresult **) ckrealloc((void *) connid->results,
								   sizeof(PGresult *) * connid->res_max);
		for (i = connid->res_last; i < connid->res_max; i++)
			connid->results[i] = NULL;
	}

	connid->results[resid] = res;
	sprintf(buf, "%s.%d", connid_c, resid);
	Tcl_SetResult(interp, buf, TCL_VOLATILE);
	return resid;
}

static int
getresid(Tcl_Interp *interp, CONST84 char *id, Pg_ConnectionId ** connid_p)
{
	Tcl_Channel conn_chan;
	char	   *mark;
	int			resid;
	Pg_ConnectionId *connid;

	if (!(mark = strchr(id, '.')))
		return -1;
	*mark = '\0';
	conn_chan = Tcl_GetChannel(interp, id, 0);
	*mark = '.';
	if (conn_chan == NULL || Tcl_GetChannelType(conn_chan) != &Pg_ConnType)
	{
		Tcl_SetResult(interp, "Invalid connection handle", TCL_STATIC);
		return -1;
	}

	if (Tcl_GetInt(interp, mark + 1, &resid) == TCL_ERROR)
	{
		Tcl_SetResult(interp, "Poorly formated result handle", TCL_STATIC);
		return -1;
	}

	connid = (Pg_ConnectionId *) Tcl_GetChannelInstanceData(conn_chan);

	if (resid < 0 || resid >= connid->res_max || connid->results[resid] == NULL)
	{
		Tcl_SetResult(interp, "Invalid result handle", TCL_STATIC);
		return -1;
	}

	*connid_p = connid;

	return resid;
}


/*
 * Get back the result pointer from the Id
 */
PGresult *