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Postgres95 1.01 Distribution - Virgin Sources
This commit is contained in:
Marc G. Fournier
269
src/backend/utils/fmgr/dfmgr.c
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269
src/backend/utils/fmgr/dfmgr.c
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/*-------------------------------------------------------------------------
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*
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* dfmgr.c--
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* Dynamic function manager code.
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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/backend/utils/fmgr/dfmgr.c,v 1.1.1.1 1996/07/09 06:22:07 scrappy Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <stdio.h>
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#include <string.h>
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#include "postgres.h"
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#include "fmgr.h" /* generated by Gen_fmgrtab.sh */
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#include "utils/dynamic_loader.h"
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#include "utils/elog.h"
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#include "utils/builtins.h"
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#include "access/heapam.h"
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#include "nodes/pg_list.h"
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#include "port-protos.h" /* system specific function prototypes */
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#include "catalog/catname.h"
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#include "utils/syscache.h"
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#include "catalog/pg_proc.h"
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static DynamicFileList *file_list = (DynamicFileList *) NULL;
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static DynamicFileList *file_tail = (DynamicFileList *) NULL;
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#define NOT_EQUAL(A, B) (((A).st_ino != (B).inode) \
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|| ((A).st_dev != (B).device))
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static Oid procedureId_save = -1;
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static int pronargs_save;
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static func_ptr user_fn_save = (func_ptr) NULL;
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static func_ptr handle_load(char *filename, char *funcname);
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func_ptr
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fmgr_dynamic(Oid procedureId, int *pronargs)
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{
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HeapTuple procedureTuple;
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Form_pg_proc procedureStruct;
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char *proname;
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char *probinattr, *probinstring;
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func_ptr user_fn, handle_load();
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Relation rdesc;
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bool isnull;
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if (procedureId == procedureId_save) {
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*pronargs = pronargs_save;
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return(user_fn_save);
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}
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/*
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* The procedure isn't a builtin, so we'll have to do a catalog
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* lookup to find its pg_proc entry.
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*/
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procedureTuple = SearchSysCacheTuple(PROOID, ObjectIdGetDatum(procedureId),
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0,0,0);
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if (!HeapTupleIsValid(procedureTuple)) {
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elog(WARN, "fmgr: Cache lookup failed for procedure %d\n",
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procedureId);
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return((func_ptr) NULL);
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}
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procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
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proname = procedureStruct->proname.data;
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pronargs_save = *pronargs = procedureStruct->pronargs;
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/*
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* Extract the procedure info from the pg_proc tuple.
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* Since probin is varlena, do a amgetattr() on the procedure
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* tuple. To do that, we need the rdesc for the procedure
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* relation, so...
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*/
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/* open pg_procedure */
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rdesc = heap_openr(ProcedureRelationName);
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if (!RelationIsValid(rdesc)) {
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elog(WARN, "fmgr: Could not open relation %s",
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ProcedureRelationName);
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return((func_ptr) NULL);
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}
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probinattr = heap_getattr(procedureTuple, (Buffer) 0,
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Anum_pg_proc_probin,
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RelationGetTupleDescriptor(rdesc), &isnull);
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if (!PointerIsValid(probinattr) /*|| isnull*/) {
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heap_close(rdesc);
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elog(WARN, "fmgr: Could not extract probin for %d from %s",
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procedureId, ProcedureRelationName);
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return((func_ptr) NULL);
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}
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probinstring = textout((struct varlena *) probinattr);
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user_fn = handle_load(probinstring, proname);
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procedureId_save = procedureId;
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user_fn_save = user_fn;
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return(user_fn);
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}
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static func_ptr
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handle_load(char *filename, char *funcname)
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{
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DynamicFileList *file_scanner = (DynamicFileList *) NULL;
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func_ptr retval = (func_ptr) NULL;
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char *load_error;
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#ifdef WIN32
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struct _stat stat_buf;
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#else
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struct stat stat_buf;
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#endif /* WIN32 */
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/*
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* Do this because loading files may screw up the dynamic function
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* manager otherwise.
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*/
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procedureId_save = -1;
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/*
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* Scan the list of loaded FILES to see if the function
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* has been loaded.
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*/
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if (filename != (char *) NULL) {
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for (file_scanner = file_list;
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file_scanner != (DynamicFileList *) NULL
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&& file_scanner->filename != (char *) NULL
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&& strcmp(filename, file_scanner->filename) != 0;
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file_scanner = file_scanner->next)
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;
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if (file_scanner == (DynamicFileList *) NULL) {
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if (stat(filename, &stat_buf) == -1) {
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elog(WARN, "stat failed on file %s", filename);
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}
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for (file_scanner = file_list;
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file_scanner != (DynamicFileList *) NULL
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&& (NOT_EQUAL(stat_buf, *file_scanner));
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file_scanner = file_scanner->next)
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;
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/*
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* Same files - different paths (ie, symlink or link)
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*/
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if (file_scanner != (DynamicFileList *) NULL)
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(void) strcpy(file_scanner->filename, filename);
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}
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} else {
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file_scanner = (DynamicFileList *) NULL;
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}
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/*
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* File not loaded yet.
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*/
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if (file_scanner == (DynamicFileList *) NULL) {
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if (file_list == (DynamicFileList *) NULL) {
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file_list = (DynamicFileList *)
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malloc(sizeof(DynamicFileList));
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file_scanner = file_list;
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} else {
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file_tail->next = (DynamicFileList *)
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malloc(sizeof(DynamicFileList));
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file_scanner = file_tail->next;
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}
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memset((char *) file_scanner, 0, sizeof(DynamicFileList));
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(void) strcpy(file_scanner->filename, filename);
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#ifndef WIN32
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file_scanner->device = stat_buf.st_dev;
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file_scanner->inode = stat_buf.st_ino;
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#endif /* WIN32 */
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file_scanner->next = (DynamicFileList *) NULL;
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file_scanner->handle = pg_dlopen(filename);
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if (file_scanner->handle == (void *)NULL) {
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load_error = pg_dlerror();
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if (file_scanner == file_list) {
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file_list = (DynamicFileList *) NULL;
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} else {
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file_tail->next = (DynamicFileList *) NULL;
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}
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free((char *) file_scanner);
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elog(WARN, "Load of file %s failed: %s", filename, load_error);
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}
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/*
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* Just load the file - we are done with that so return.
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*/
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file_tail = file_scanner;
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if (funcname == (char *) NULL)
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return((func_ptr) NULL);
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}
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retval = pg_dlsym(file_scanner->handle, funcname);
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if (retval == (func_ptr) NULL) {
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elog(WARN, "Can't find function %s in file %s", funcname, filename);
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}
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return(retval);
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}
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/*
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* This function loads files by the following:
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*
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* If the file is already loaded:
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* o Zero out that file's loaded space (so it doesn't screw up linking)
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* o Free all space associated with that file
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* o Free that file's descriptor.
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*
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* Now load the file by calling handle_load with a NULL argument as the
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* function.
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*/
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void
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load_file(char *filename)
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{
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DynamicFileList *file_scanner, *p;
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#ifdef WIN32
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struct _stat stat_buf;
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#else
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struct stat stat_buf;
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#endif /* WIN32 */
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int done = 0;
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if (stat(filename, &stat_buf) == -1) {
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elog(WARN, "stat failed on file %s", filename);
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}
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if (file_list != (DynamicFileList *) NULL
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&& !NOT_EQUAL(stat_buf, *file_list)) {
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file_scanner = file_list;
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file_list = file_list->next;
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pg_dlclose(file_scanner->handle);
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free((char *) file_scanner);
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} else if (file_list != (DynamicFileList *) NULL) {
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file_scanner = file_list;
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while (!done) {
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if (file_scanner->next == (DynamicFileList *) NULL) {
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done = 1;
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} else if (!NOT_EQUAL(stat_buf, *(file_scanner->next))) {
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done = 1;
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} else {
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file_scanner = file_scanner->next;
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}
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}
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if (file_scanner->next != (DynamicFileList *) NULL) {
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p = file_scanner->next;
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file_scanner->next = file_scanner->next->next;
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pg_dlclose(file_scanner->handle);
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free((char *)p);
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}
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}
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handle_load(filename, (char *) NULL);
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}
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