653 lines
12 KiB
C
653 lines
12 KiB
C
/*-------------------------------------------------------------------------
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*
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* fe-lobj.c--
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* Front-end large object interface
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-lobj.c,v 1.11 1997/09/18 20:22:49 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include "postgres.h"
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#include "libpq-fe.h"
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#include "libpq/libpq-fs.h"
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#define LO_BUFSIZE 1024
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static int lo_initialize(PGconn *conn);
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/*
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* lo_open
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* opens an existing large object
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*
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* returns the file descriptor for use in later lo_* calls
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* return -1 upon failure.
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*/
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int
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lo_open(PGconn *conn, Oid lobjId, int mode)
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{
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int fd;
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int result_len;
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PQArgBlock argv[2];
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PGresult *res;
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argv[0].isint = 1;
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argv[0].len = 4;
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argv[0].u.integer = lobjId;
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argv[1].isint = 1;
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argv[1].len = 4;
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argv[1].u.integer = mode;
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if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
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{
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if (lo_initialize(conn) < 0)
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{
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return -1;
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}
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}
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res = PQfn(conn, conn->lobjfuncs->fn_lo_open, &fd, &result_len, 1, argv, 2);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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/* have to do this to reset offset in shared fd cache */
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/* but only if fd is valid */
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if (fd >= 0 && lo_lseek(conn, fd, 0L, SEEK_SET) < 0)
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return -1;
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return fd;
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}
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else
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return -1;
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}
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/*
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* lo_close
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* closes an existing large object
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*
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* returns 0 upon success
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* returns -1 upon failure.
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*/
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int
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lo_close(PGconn *conn, int fd)
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{
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PQArgBlock argv[1];
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PGresult *res;
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int retval;
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int result_len;
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if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
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{
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if (lo_initialize(conn) < 0)
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{
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return -1;
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}
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}
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argv[0].isint = 1;
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argv[0].len = 4;
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argv[0].u.integer = fd;
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res = PQfn(conn, conn->lobjfuncs->fn_lo_close,
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&retval, &result_len, 1, argv, 1);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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return retval;
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}
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else
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return -1;
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}
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/*
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* lo_read
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* read len bytes of the large object into buf
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*
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* returns the length of bytes read.
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* the CALLER must have allocated enough space to hold the result returned
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*/
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int
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lo_read(PGconn *conn, int fd, char *buf, int len)
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{
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PQArgBlock argv[2];
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PGresult *res;
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int result_len;
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if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
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{
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if (lo_initialize(conn) < 0)
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{
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return -1;
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}
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}
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argv[0].isint = 1;
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argv[0].len = 4;
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argv[0].u.integer = fd;
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argv[1].isint = 1;
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argv[1].len = 4;
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argv[1].u.integer = len;
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res = PQfn(conn, conn->lobjfuncs->fn_lo_read,
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(int *) buf, &result_len, 0, argv, 2);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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return result_len;
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}
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else
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return -1;
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}
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/*
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* lo_write
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* write len bytes of buf into the large object fd
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*
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*/
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int
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lo_write(PGconn *conn, int fd, char *buf, int len)
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{
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PQArgBlock argv[2];
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PGresult *res;
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int result_len;
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int retval;
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if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
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{
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if (lo_initialize(conn) < 0)
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{
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return -1;
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}
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}
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if (len <= 0)
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return 0;
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argv[0].isint = 1;
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argv[0].len = 4;
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argv[0].u.integer = fd;
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argv[1].isint = 0;
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argv[1].len = len;
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argv[1].u.ptr = (int *) buf;
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res = PQfn(conn, conn->lobjfuncs->fn_lo_write,
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&retval, &result_len, 1, argv, 2);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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return retval;
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}
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else
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return -1;
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}
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/*
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* lo_lseek
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* change the current read or write location on a large object
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* currently, only L_SET is a legal value for whence
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*
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*/
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int
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lo_lseek(PGconn *conn, int fd, int offset, int whence)
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{
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PQArgBlock argv[3];
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PGresult *res;
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int retval;
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int result_len;
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if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
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{
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if (lo_initialize(conn) < 0)
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{
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return -1;
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}
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}
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argv[0].isint = 1;
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argv[0].len = 4;
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argv[0].u.integer = fd;
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argv[1].isint = 1;
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argv[1].len = 4;
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argv[1].u.integer = offset;
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argv[2].isint = 1;
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argv[2].len = 4;
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argv[2].u.integer = whence;
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res = PQfn(conn, conn->lobjfuncs->fn_lo_lseek,
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&retval, &result_len, 1, argv, 3);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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return retval;
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}
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else
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return -1;
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}
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/*
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* lo_creat
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* create a new large object
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* the mode is a bitmask describing different attributes of the new object
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*
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* returns the oid of the large object created or
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* InvalidOid upon failure
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*/
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Oid
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lo_creat(PGconn *conn, int mode)
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{
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PQArgBlock argv[1];
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PGresult *res;
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int retval;
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int result_len;
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if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
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{
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if (lo_initialize(conn) < 0)
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{
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return -1;
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}
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}
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argv[0].isint = 1;
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argv[0].len = 4;
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argv[0].u.integer = mode;
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res = PQfn(conn, conn->lobjfuncs->fn_lo_creat,
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&retval, &result_len, 1, argv, 1);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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return (Oid) retval;
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}
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else
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return InvalidOid;
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}
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/*
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* lo_tell
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* returns the current seek location of the large object
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*
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*/
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int
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lo_tell(PGconn *conn, int fd)
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{
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int retval;
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PQArgBlock argv[1];
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PGresult *res;
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int result_len;
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if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
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{
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if (lo_initialize(conn) < 0)
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{
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return -1;
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}
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}
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argv[0].isint = 1;
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argv[0].len = 4;
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argv[0].u.integer = fd;
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res = PQfn(conn, conn->lobjfuncs->fn_lo_tell,
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&retval, &result_len, 1, argv, 1);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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return retval;
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}
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else
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return -1;
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}
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/*
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* lo_unlink
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* delete a file
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*
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*/
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int
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lo_unlink(PGconn *conn, Oid lobjId)
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{
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PQArgBlock argv[1];
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PGresult *res;
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int result_len;
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int retval;
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if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
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{
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if (lo_initialize(conn) < 0)
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{
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return -1;
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}
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}
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argv[0].isint = 1;
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argv[0].len = 4;
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argv[0].u.integer = lobjId;
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res = PQfn(conn, conn->lobjfuncs->fn_lo_unlink,
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&retval, &result_len, 1, argv, 1);
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if (PQresultStatus(res) == PGRES_COMMAND_OK)
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{
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PQclear(res);
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return retval;
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}
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else
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return -1;
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}
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/*
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* lo_import -
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* imports a file as an (inversion) large object.
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* returns the oid of that object upon success,
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* returns InvalidOid upon failure
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*
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*/
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Oid
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lo_import(PGconn *conn, char *filename)
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{
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int fd;
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int nbytes,
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tmp;
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char buf[LO_BUFSIZE];
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Oid lobjOid;
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int lobj;
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/*
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* open the file to be read in
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*/
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fd = open(filename, O_RDONLY, 0666);
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if (fd < 0)
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{ /* error */
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sprintf(conn->errorMessage,
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"lo_import: can't open unix file\"%s\"\n", filename);
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return InvalidOid;
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}
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/*
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* create an inversion "object"
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*/
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lobjOid = lo_creat(conn, INV_READ | INV_WRITE);
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if (lobjOid == InvalidOid)
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{
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sprintf(conn->errorMessage,
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"lo_import: can't create inv object for \"%s\"", filename);
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return InvalidOid;
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}
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lobj = lo_open(conn, lobjOid, INV_WRITE);
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if (lobj == -1)
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{
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sprintf(conn->errorMessage,
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"lo_import: could not open inv object oid %d", lobjOid);
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return InvalidOid;
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}
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/*
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* read in from the Unix file and write to the inversion file
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*/
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while ((nbytes = read(fd, buf, LO_BUFSIZE)) > 0)
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{
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tmp = lo_write(conn, lobj, buf, nbytes);
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if (tmp < nbytes)
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{
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sprintf(conn->errorMessage,
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"lo_import: error while reading \"%s\"", filename);
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return InvalidOid;
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}
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}
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(void) close(fd);
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(void) lo_close(conn, lobj);
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return lobjOid;
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}
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/*
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* lo_export -
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* exports an (inversion) large object.
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* returns -1 upon failure, 1 otherwise
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*/
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int
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lo_export(PGconn *conn, Oid lobjId, char *filename)
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{
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int fd;
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int nbytes,
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tmp;
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char buf[LO_BUFSIZE];
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int lobj;
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/*
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* create an inversion "object"
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*/
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lobj = lo_open(conn, lobjId, INV_READ);
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if (lobj == -1)
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{
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sprintf(conn->errorMessage,
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"lo_export: can't open inv object %d", lobjId);
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return -1;
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}
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/*
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* open the file to be written to
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*/
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fd = open(filename, O_CREAT | O_WRONLY, 0666);
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if (fd < 0)
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{ /* error */
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sprintf(conn->errorMessage,
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"lo_export: can't open unix file\"%s\"", filename);
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return 0;
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}
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/*
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* read in from the Unix file and write to the inversion file
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*/
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while ((nbytes = lo_read(conn, lobj, buf, LO_BUFSIZE)) > 0)
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{
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tmp = write(fd, buf, nbytes);
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if (tmp < nbytes)
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{
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sprintf(conn->errorMessage,
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"lo_export: error while writing \"%s\"",
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filename);
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return -1;
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}
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}
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(void) lo_close(conn, lobj);
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(void) close(fd);
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return 1;
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}
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/* ----------------
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* lo_initialize
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*
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* Initialize the large object interface for an existing connection.
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* We ask the backend about the functions OID's in pg_proc for all
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* functions that are required for large object operations.
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* ----------------
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*/
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static int
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lo_initialize(PGconn *conn)
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{
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PGresult *res;
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PGlobjfuncs *lobjfuncs;
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int n;
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char *fname;
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Oid foid;
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/* ----------------
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* Allocate the structure to hold the functions OID's
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* ----------------
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*/
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lobjfuncs = (PGlobjfuncs *) malloc(sizeof(PGlobjfuncs));
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if (lobjfuncs == (PGlobjfuncs *) NULL)
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{
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strcpy(conn->errorMessage,
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"FATAL: malloc() failed in lo_initialize()\n");
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return -1;
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}
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MemSet((char *) lobjfuncs, 0, sizeof(PGlobjfuncs));
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/* ----------------
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* Execute the query to get all the functions at once
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* ----------------
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*/
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res = PQexec(conn, "select proname, oid from pg_proc \
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where proname = 'lo_open' \
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or proname = 'lo_close' \
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or proname = 'lo_creat' \
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or proname = 'lo_unlink' \
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or proname = 'lo_lseek' \
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or proname = 'lo_tell' \
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or proname = 'loread' \
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or proname = 'lowrite'");
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if (res == (PGresult *) NULL)
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{
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free(lobjfuncs);
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return -1;
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}
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if (res->resultStatus != PGRES_TUPLES_OK)
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{
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free(lobjfuncs);
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PQclear(res);
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strcpy(conn->errorMessage,
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"ERROR: SELECT didn't return data in lo_initialize()\n");
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return -1;
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}
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/* ----------------
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* Examine the result and put the OID's into the struct
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* ----------------
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*/
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for (n = 0; n < PQntuples(res); n++)
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{
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fname = PQgetvalue(res, n, 0);
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foid = (Oid) atoi(PQgetvalue(res, n, 1));
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if (!strcmp(fname, "lo_open"))
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{
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lobjfuncs->fn_lo_open = foid;
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}
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else if (!strcmp(fname, "lo_close"))
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{
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lobjfuncs->fn_lo_close = foid;
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}
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else if (!strcmp(fname, "lo_creat"))
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{
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lobjfuncs->fn_lo_creat = foid;
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}
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else if (!strcmp(fname, "lo_unlink"))
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{
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lobjfuncs->fn_lo_unlink = foid;
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}
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else if (!strcmp(fname, "lo_lseek"))
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{
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lobjfuncs->fn_lo_lseek = foid;
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}
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else if (!strcmp(fname, "lo_tell"))
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{
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lobjfuncs->fn_lo_tell = foid;
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}
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else if (!strcmp(fname, "loread"))
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{
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lobjfuncs->fn_lo_read = foid;
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}
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else if (!strcmp(fname, "lowrite"))
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{
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lobjfuncs->fn_lo_write = foid;
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}
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}
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PQclear(res);
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/* ----------------
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* Finally check that we really got all large object
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* interface functions.
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* ----------------
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*/
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if (lobjfuncs->fn_lo_open == 0)
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{
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strcpy(conn->errorMessage,
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"ERROR: Cannot determine OID for function lo_open\n");
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free(lobjfuncs);
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return -1;
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}
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if (lobjfuncs->fn_lo_close == 0)
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{
|
|
strcpy(conn->errorMessage,
|
|
"ERROR: Cannot determine OID for function lo_close\n");
|
|
free(lobjfuncs);
|
|
return -1;
|
|
}
|
|
if (lobjfuncs->fn_lo_creat == 0)
|
|
{
|
|
strcpy(conn->errorMessage,
|
|
"ERROR: Cannot determine OID for function lo_creat\n");
|
|
free(lobjfuncs);
|
|
return -1;
|
|
}
|
|
if (lobjfuncs->fn_lo_unlink == 0)
|
|
{
|
|
strcpy(conn->errorMessage,
|
|
"ERROR: Cannot determine OID for function lo_unlink\n");
|
|
free(lobjfuncs);
|
|
return -1;
|
|
}
|
|
if (lobjfuncs->fn_lo_lseek == 0)
|
|
{
|
|
strcpy(conn->errorMessage,
|
|
"ERROR: Cannot determine OID for function lo_lseek\n");
|
|
free(lobjfuncs);
|
|
return -1;
|
|
}
|
|
if (lobjfuncs->fn_lo_tell == 0)
|
|
{
|
|
strcpy(conn->errorMessage,
|
|
"ERROR: Cannot determine OID for function lo_tell\n");
|
|
free(lobjfuncs);
|
|
return -1;
|
|
}
|
|
if (lobjfuncs->fn_lo_read == 0)
|
|
{
|
|
strcpy(conn->errorMessage,
|
|
"ERROR: Cannot determine OID for function loread\n");
|
|
free(lobjfuncs);
|
|
return -1;
|
|
}
|
|
if (lobjfuncs->fn_lo_write == 0)
|
|
{
|
|
strcpy(conn->errorMessage,
|
|
"ERROR: Cannot determine OID for function lowrite\n");
|
|
free(lobjfuncs);
|
|
return -1;
|
|
}
|
|
|
|
/* ----------------
|
|
* Put the structure into the connection control
|
|
* ----------------
|
|
*/
|
|
conn->lobjfuncs = lobjfuncs;
|
|
return 0;
|
|
}
|