Postgres95 1.01 Distribution - Virgin Sources

src/interfaces/libpq/fe-lobj.c

@@ -0,0 +1,381 @@
+/*-------------------------------------------------------------------------
+ *
+ * fe-lobj.c--
+ *    Front-end large object interface
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *    $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-lobj.c,v 1.1.1.1 1996/07/09 06:22:17 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include "postgres.h"
+#include "libpq-fe.h"
+#include "obj/fmgr.h" 
+#include "libpq/libpq-fs.h"
+
+#ifndef MAXPATHLEN
+#define MAXPATHLEN 1024
+#endif
+
+#define LO_BUFSIZE        1024
+
+/*
+ * lo_open
+ *    opens an existing large object
+ *
+ * returns the file descriptor for use in later lo_* calls
+ * return -1 upon failure.
+ */
+int
+lo_open(PGconn* conn, Oid lobjId, int mode)
+{
+    int fd;
+    int result_len;
+    PQArgBlock argv[2];
+    PGresult *res;
+
+    argv[0].isint = 1;
+    argv[0].len = 4;
+    argv[0].u.integer = lobjId;
+
+    argv[1].isint = 1;
+    argv[1].len = 4;
+    argv[1].u.integer = mode;
+    
+    res = PQfn(conn, F_LO_OPEN,&fd,&result_len,1,argv,2); 
+    if (PQresultStatus(res) == PGRES_COMMAND_OK) {
+	PQclear(res);
+
+	/* have to do this to reset offset in shared fd cache */
+	/* but only if fd is valid */
+	if (fd >= 0 && lo_lseek(conn, fd, 0L, SEEK_SET) < 0)
+	    return -1;
+	return fd;
+    } else
+	return -1;
+}
+
+/*
+ * lo_close
+ *    closes an existing large object
+ *
+ * returns 0 upon success
+ * returns -1 upon failure.
+ */
+int
+lo_close(PGconn *conn, int fd)
+{
+    PQArgBlock argv[1];
+    PGresult *res;
+    int retval;
+    int result_len;
+
+    argv[0].isint = 1;
+    argv[0].len = 4;
+    argv[0].u.integer = fd;
+    res = PQfn(conn, F_LO_CLOSE,&retval,&result_len,1,argv,1);
+    if (PQresultStatus(res) == PGRES_COMMAND_OK) {
+	PQclear(res);
+	return retval;
+    } else
+	return -1;
+}
+
+/*
+ * lo_read
+ *    read len bytes of the large object into buf
+ *
+ * returns the length of bytes read.
+ * the CALLER must have allocated enough space to hold the result returned
+ */
+
+int
+lo_read(PGconn *conn, int fd, char *buf, int len)
+{
+    PQArgBlock argv[2];
+    PGresult *res;
+    int result_len;
+
+    argv[0].isint = 1;
+    argv[0].len = 4;
+    argv[0].u.integer = fd;
+
+    argv[1].isint = 1;
+    argv[1].len = 4;
+    argv[1].u.integer = len;
+
+    res = PQfn(conn, F_LOREAD,(int*)buf,&result_len,0,argv,2);
+    if (PQresultStatus(res) == PGRES_COMMAND_OK) {
+	PQclear(res);
+	return result_len;
+    } else
+	return -1;
+}
+
+/*
+ * lo_write
+ *    write len bytes of buf into the large object fd
+ *
+ */
+int
+lo_write(PGconn *conn, int fd, char *buf, int len)
+{
+    PQArgBlock argv[2];
+    PGresult *res;
+    int result_len;
+    int retval;
+
+    if (len <= 0)
+	return 0;
+
+    argv[0].isint = 1;
+    argv[0].len = 4;
+    argv[0].u.integer = fd;
+
+    argv[1].isint = 0;
+    argv[1].len = len;
+    argv[1].u.ptr = (int*)buf;
+
+    res = PQfn(conn, F_LOWRITE,&retval,&result_len,1,argv,2);
+    if (PQresultStatus(res) == PGRES_COMMAND_OK) {
+	PQclear(res);
+	return retval;
+    } else
+	return -1;
+}
+
+/*
+ * lo_lseek
+ *    change the current read or write location on a large object
+ * currently, only L_SET is a legal value for whence
+ *
+ */
+
+int
+lo_lseek(PGconn *conn, int fd, int offset, int whence)
+{
+    PQArgBlock argv[3];
+    PGresult *res;
+    int retval; 
+    int result_len;
+    
+    argv[0].isint = 1;
+    argv[0].len = 4;
+    argv[0].u.integer = fd;
+    
+    argv[1].isint = 1;
+    argv[1].len = 4;
+    argv[1].u.integer = offset;
+
+    argv[2].isint = 1;
+    argv[2].len = 4;
+    argv[2].u.integer = whence;
+
+    res = PQfn(conn, F_LO_LSEEK,&retval,&result_len,1,argv,3);
+    if (PQresultStatus(res) == PGRES_COMMAND_OK) {
+	PQclear(res);
+	return retval;
+    } else
+	return -1;
+}
+
+/*
+ * lo_creat
+ *    create a new large object
+ * the mode is a bitmask describing different attributes of the new object
+ *
+ * returns the oid of the large object created or
+ * InvalidOid upon failure
+ */
+
+Oid
+lo_creat(PGconn *conn, int mode)
+{
+    PQArgBlock argv[1];
+    PGresult *res;
+    int retval;
+    int result_len;
+
+    argv[0].isint = 1;
+    argv[0].len = 4;
+    argv[0].u.integer = mode;
+    res  = PQfn(conn, F_LO_CREAT,&retval,&result_len,1,argv,1);
+    if (PQresultStatus(res) == PGRES_COMMAND_OK) {
+	PQclear(res);
+	return (Oid)retval;
+    } else
+	return InvalidOid;
+}
+
+
+/*
+ * lo_tell
+ *    returns the current seek location of the large object
+ *
+ */
+
+int
+lo_tell(PGconn *conn, int fd)
+{
+    int retval;
+    PQArgBlock argv[1];
+    PGresult *res;
+    int result_len;
+
+    argv[0].isint = 1;
+    argv[0].len = 4;
+    argv[0].u.integer = fd;
+
+    res = PQfn(conn, F_LO_TELL,&retval,&result_len,1,argv,1);
+    if (PQresultStatus(res) == PGRES_COMMAND_OK) {
+	PQclear(res);
+	return retval;
+    } else
+	return -1;
+}
+
+/*
+ * lo_unlink
+ *    delete a file
+ *
+ */
+
+int
+lo_unlink(PGconn *conn, Oid lobjId)
+{
+    PQArgBlock argv[1];
+    PGresult *res;
+    int result_len;
+    int retval;
+
+    argv[0].isint = 1;
+    argv[0].len = 4;
+    argv[0].u.integer = lobjId;
+
+    res = PQfn(conn, F_LO_UNLINK,&retval,&result_len,1,argv,1);
+    if (PQresultStatus(res) == PGRES_COMMAND_OK) {
+	PQclear(res);
+	return retval;
+    } else
+	return -1;
+}
+
+/*
+ * lo_import -
+ *    imports a file as an (inversion) large object.
+ *      returns the oid of that object upon success,
+ * returns InvalidOid upon failure
+ *
+ */
+
+Oid
+lo_import(PGconn *conn, char* filename)
+{
+    int fd;
+    int nbytes, tmp;
+    char buf[LO_BUFSIZE];
+    Oid lobjOid;
+    int lobj;
+    
+    /*
+     * open the file to be read in
+     */
+    fd = open(filename, O_RDONLY, 0666);
+    if (fd < 0)  {   /* error */
+	sprintf(conn->errorMessage,
+		"lo_import: can't open unix file\"%s\"\n", filename);
+	return InvalidOid;
+    }
+
+    /*
+     * create an inversion "object"
+     */
+    lobjOid = lo_creat(conn, INV_READ|INV_WRITE);
+    if (lobjOid == InvalidOid) {
+	sprintf(conn->errorMessage,
+	        "lo_import: can't create inv object for \"%s\"", filename);
+	return InvalidOid;
+    }
+
+    lobj = lo_open(conn, lobjOid, INV_WRITE);
+    if (lobj == -1) {
+	sprintf(conn->errorMessage,
+		"lo_import: could not open inv object oid %d",lobjOid);
+	return InvalidOid;
+    }
+    /*
+     * read in from the Unix file and write to the inversion file
+     */
+    while ((nbytes = read(fd, buf, LO_BUFSIZE)) > 0) {
+	tmp = lo_write(conn,lobj, buf, nbytes);
+        if (tmp < nbytes) {
+	    sprintf(conn->errorMessage,
+		    "lo_import: error while reading \"%s\"",filename);
+	    return InvalidOid;
+	}
+    }
+
+    (void) close(fd);
+    (void) lo_close(conn, lobj);
+
+    return lobjOid;
+}
+
+/*
+ * lo_export -
+ *    exports an (inversion) large object.
+ * returns -1 upon failure, 1 otherwise
+ */
+int
+lo_export(PGconn *conn, Oid lobjId, char *filename)
+{
+    int fd;
+    int nbytes, tmp;
+    char buf[LO_BUFSIZE];
+    int lobj;
+
+    /*
+     * create an inversion "object"
+     */
+    lobj = lo_open(conn, lobjId, INV_READ);
+    if (lobj == -1) {
+	sprintf(conn->errorMessage,
+		"lo_export: can't open inv object %d",lobjId);
+	return -1;
+    }
+
+    /*
+     * open the file to be written to
+     */
+    fd = open(filename, O_CREAT|O_WRONLY, 0666);
+    if (fd < 0)  {   /* error */
+	sprintf(conn->errorMessage,
+		"lo_export: can't open unix file\"%s\"",filename);
+	return 0;
+    }
+
+    /*
+     * read in from the Unix file and write to the inversion file
+     */
+    while ((nbytes = lo_read(conn, lobj, buf, LO_BUFSIZE)) > 0) {
+	tmp = write(fd, buf, nbytes);
+        if (tmp < nbytes) {
+	    sprintf(conn->errorMessage,
+		    "lo_export: error while writing \"%s\"",
+		    filename);
+	    return -1;
+	}
+    }
+
+    (void) lo_close(conn,lobj);
+    (void) close(fd);
+
+    return 1;
+}