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+/*-------------------------------------------------------------------------
+ *
+ * be-dumpdata.c--
+ * support for collection of returned tuples from an internal
+ * PQ call into a backend buffer.
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * $Header: /cvsroot/pgsql/src/backend/libpq/Attic/be-dumpdata.c,v 1.1.1.1 1996/07/09 06:21:30 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+/*
+ * INTERFACE ROUTINES
+ * be_portalinit - initialize backend portal administration
+ * be_portalpush - add a portal to the top of the portal stack
+ * be_portalpop - remove portal on the top of the stack & return it
+ * be_currentportal - return the top portal on the portal stack
+ * be_newportal - return a new portal.
+ * be_portalinit - initialize backend portal expected to hold results.
+ * be_printtup - add a tuple to a backend portal
+ *
+ * NOTES
+ * Since backend user-defined operators can call queries
+ * which in turn call user-defined operators can call queries...
+ * we have to keep track of portals on a stack. BeginCommand()
+ * puts portals on the stack and the PQ functions remove them.
+ *
+ */
+#include "postgres.h"
+
+#include "lib/dllist.h"
+#include "libpq/libpq-be.h"
+
+#include "access/heapam.h"
+#include "access/htup.h"
+#include "storage/buf.h"
+#include "utils/memutils.h"
+#include "utils/palloc.h"
+#include "fmgr.h"
+#include "utils/mcxt.h"
+#include "utils/elog.h"
+#include "utils/exc.h"
+
+#include "utils/syscache.h"
+#include "catalog/pg_type.h"
+#include "catalog/catalog.h"
+#include "access/printtup.h"
+
+/* ----------------
+ * backend portal stack for recursive PQexec calls
+ * ----------------
+ */
+static Dllist *be_portalstack;
+
+/* ----------------
+ * be_portalinit - initialize backend portal administration
+ *
+ * This is called once from InitPostgres() to initialize
+ * the portal stack.
+ * ----------------
+ */
+void
+be_portalinit()
+{
+ be_portalstack = DLNewList();
+}
+
+/* ----------------
+ * be_portalpush - add a portal to the top of the portal stack
+ *
+ * used by BeginCommand()
+ * ----------------
+ */
+void
+be_portalpush(PortalEntry *entry)
+{
+ DLAddTail(be_portalstack, DLNewElem(entry));
+}
+
+/* ----------------
+ * be_portalpop - remove the portal on the top of the stack & return it
+ *
+ * used by PQexec()
+ * ----------------
+ */
+PortalEntry *
+be_portalpop()
+{
+ PortalEntry *p;
+ Dlelem* elt;
+ elt = DLRemTail(be_portalstack);
+
+ p = (elt ? (PortalEntry*)DLE_VAL(elt) : NULL);
+ DLFreeElem(elt);
+ return p;
+
+
+}
+
+/* ----------------
+ * be_currentportal - return the top portal on the portal stack
+ *
+ * used by be_printtup()
+ * ----------------
+ */
+PortalEntry *
+be_currentportal()
+{
+ Dlelem* elt;
+ elt = DLGetTail(be_portalstack);
+ return (elt ? (PortalEntry*)DLE_VAL(elt) : NULL);
+}
+
+/* ----------------
+ * be_newportal - return a new portal.
+ *
+ * If the user-defined function does not specify a portal name,
+ * we generate a unique one. Names are generated from a combination
+ * of a postgres oid and an integer counter which is incremented
+ * every time we ask for a local portal.
+ *
+ * used by BeginCommand()
+ * ----------------
+ */
+
+static Oid be_portaloid;
+static u_int be_portalcnt = 0;
+
+PortalEntry *
+be_newportal()
+{
+ PortalEntry *entry;
+ char buf[PortalNameLength];
+
+ /* ----------------
+ * generate a new name
+ * ----------------
+ */
+ if (be_portalcnt == 0)
+ be_portaloid = newoid();
+ be_portalcnt++;
+ sprintf(buf, "be_%d_%d", be_portaloid, be_portalcnt);
+
+ /* ----------------
+ * initialize the new portal entry and keep track
+ * of the current memory context for be_printtup().
+ * This is important - otherwise whatever we allocate
+ * will go away and the contents of the portal after
+ * PQexec() returns will be meaningless.
+ * ----------------
+ */
+ entry = pbuf_setup(buf);
+ entry->portalcxt = (Pointer) CurrentMemoryContext;
+
+ return entry;
+}
+
+/* ----------------
+ * be_typeinit - initialize backend portal expected to hold
+ * query results.
+ *
+ * used by BeginCommand()
+ * ----------------
+ */
+void
+be_typeinit(PortalEntry *entry,
+ TupleDesc tupDesc,
+ int natts)
+{
+ PortalBuffer *portal;
+ GroupBuffer *group;
+ int i;
+ AttributeTupleForm *attrs = tupDesc->attrs;
+
+ /* ----------------
+ * add a new portal group to the portal
+ * ----------------
+ */
+ portal = entry->portal;
+ portal->no_groups++;
+ portal->groups = group = pbuf_addGroup(portal);
+ group->no_fields = natts;
+
+ /* ----------------
+ * initialize portal group type info
+ * ----------------
+ */
+ if (natts > 0) {
+ group->types = pbuf_addTypes(natts);
+ for (i = 0; i < natts; ++i) {
+ strncpy(group->types[i].name, attrs[i]->attname.data, NAMEDATALEN);
+ group->types[i].adtid = attrs[i]->atttypid;
+ group->types[i].adtsize = attrs[i]->attlen;
+ }
+ }
+}
+
+/* ----------------
+ * be_printtup - add a tuple to a backend portal
+ *
+ * used indirectly by ExecRetrieve()
+ *
+ * This code is pretty much copied from printtup(), dump_type()
+ * and dump_data(). -cim 2/12/91
+ * ----------------
+ */
+void
+be_printtup(HeapTuple tuple, TupleDesc typeinfo)
+{
+ int i;
+ char *attr;
+ bool isnull;
+ Oid typoutput;
+
+ PortalEntry *entry = NULL;
+ PortalBuffer *portal = NULL;
+ GroupBuffer *group = NULL ;
+ TupleBlock *tuples = NULL;
+ char **values;
+ int *lengths;
+
+ MemoryContext savecxt;
+
+ /* ----------------
+ * get the current portal and group
+ * ----------------
+ */
+ entry = be_currentportal();
+ portal = entry->portal;
+ group = portal->groups;
+
+ /* ----------------
+ * switch to the portal's memory context so that
+ * the tuples we allocate are returned to the user.
+ * ----------------
+ */
+ savecxt = MemoryContextSwitchTo((MemoryContext)entry->portalcxt);
+
+ /* ----------------
+ * If no tuple block yet, allocate one.
+ * If the current block is full, allocate another one.
+ * ----------------
+ */
+ if (group->tuples == NULL) {
+ tuples = group->tuples = pbuf_addTuples();
+ tuples->tuple_index = 0;
+ } else {
+ tuples = group->tuples;
+ /* walk to the end of the linked list of TupleBlocks */
+ while (tuples->next)
+ tuples = tuples->next;
+ /* now, tuples is the last TupleBlock, check to see if it is full.
+ If so, allocate a new TupleBlock and add it to the end of
+ the chain */
+
+ if (tuples->tuple_index == TupleBlockSize) {
+ tuples->next = pbuf_addTuples();
+ tuples = tuples->next;
+ tuples->tuple_index = 0;
+ }
+ }
+
+ /* ----------------
+ * Allocate space for a tuple.
+ * ----------------
+ */
+ tuples->values[tuples->tuple_index] = pbuf_addTuple(tuple->t_natts);
+ tuples->lengths[tuples->tuple_index] = pbuf_addTupleValueLengths(tuple->t_natts);
+ /* ----------------
+ * copy printable representations of the tuple's attributes
+ * to the portal.
+ *
+ * This seems silly, because the user's function which is calling
+ * PQexec() or PQfn() will probably just convert this back into the
+ * internal form anyways, but the point here is to provide a uniform
+ * libpq interface and this is how the fe libpq interface currently
+ * works. Pretty soon we'll have to add code to let the fe or be
+ * select the desired data representation and then deal with that.
+ * This should not be too hard, as there already exist typrecieve()
+ * and typsend() procedures for user-defined types (see pg_type.h)
+ * -cim 2/11/91
+ * ----------------
+ */
+
+ values = tuples->values[tuples->tuple_index];
+ lengths = tuples->lengths[tuples->tuple_index];
+
+ for (i = 0; i < tuple->t_natts; i++) {
+ attr = heap_getattr(tuple, InvalidBuffer, i+1, typeinfo, &isnull);
+ typoutput = typtoout((Oid) typeinfo->attrs[i]->atttypid);
+
+ lengths[i] = typeinfo->attrs[i]->attlen;
+
+ if (lengths[i] == -1) /* variable length attribute */
+ if (!isnull)
+ lengths[i] = VARSIZE(attr)-VARHDRSZ;
+ else
+ lengths[i] = 0;
+
+ if (!isnull && OidIsValid(typoutput)) {
+ values[i] = fmgr(typoutput, attr, gettypelem(typeinfo->attrs[i]->atttypid));
+ } else
+ values[i] = NULL;
+
+ }
+
+ /* ----------------
+ * increment tuple group counters
+ * ----------------
+ */
+ portal->no_tuples++;
+ group->no_tuples++;
+ tuples->tuple_index++;
+
+ /* ----------------
+ * return to the original memory context
+ * ----------------
+ */
+ MemoryContextSwitchTo(savecxt);
+}
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