Postgres95 1.01 Distribution - Virgin SourcesPG95-1_01

1 files changed, 236 insertions, 0 deletions

diff --git a/src/backend/executor/execFlatten.c b/src/backend/executor/execFlatten.c
new file mode 100644
index 00000000000..646c571506e
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+++ b/src/backend/executor/execFlatten.c
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+/*-------------------------------------------------------------------------
+ *
+ * execFlatten.c--
+ *    This file handles the nodes associated with flattening sets in the
+ *    target list of queries containing functions returning sets.
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *    $Header: /cvsroot/pgsql/src/backend/executor/Attic/execFlatten.c,v 1.1.1.1 1996/07/09 06:21:24 scrappy Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/*
+ * ExecEvalIter() -
+ *   Iterate through the all return tuples/base types from a function one
+ *   at time (i.e. one per ExecEvalIter call).  Not really needed for
+ *   postquel functions, but for reasons of orthogonality, these nodes
+ *   exist above pq functions as well as c functions.
+ *
+ * ExecEvalFjoin() -
+ *   Given N Iter nodes return a vector of all combinations of results
+ *   one at a time (i.e. one result vector per ExecEvalFjoin call).  This
+ *   node does the actual flattening work.
+ */
+#include "postgres.h"
+#include "nodes/primnodes.h"
+#include "nodes/relation.h"
+#include "nodes/execnodes.h"
+#include "executor/executor.h"
+#include "executor/execFlatten.h"
+
+Datum
+ExecEvalIter(Iter *iterNode,
+	     ExprContext *econtext,
+	     bool *resultIsNull,
+	     bool *iterIsDone)
+{
+    Node *expression;
+    
+    expression = iterNode->iterexpr;
+    
+    /*
+     * Really Iter nodes are only needed for C functions, postquel function
+     * by their nature return 1 result at a time.  For now we are only worrying
+     * about postquel functions, c functions will come later.
+     */
+    return ExecEvalExpr(expression, econtext, resultIsNull, iterIsDone);
+}
+
+void
+ExecEvalFjoin(TargetEntry *tlist,
+	      ExprContext *econtext,
+	      bool *isNullVect,
+	      bool *fj_isDone)
+{
+
+#ifdef SETS_FIXED
+    bool     isDone;
+    int      curNode;
+    List     *tlistP;
+
+    Fjoin    *fjNode     = tlist->fjoin;
+    DatumPtr resVect    = fjNode->fj_results;
+    BoolPtr  alwaysDone = fjNode->fj_alwaysDone;
+    
+    if (fj_isDone) *fj_isDone = false;
+    /*
+     * For the next tuple produced by the plan, we need to re-initialize
+     * the Fjoin node.
+     */
+    if (!fjNode->fj_initialized)
+	{
+	    /*
+	     * Initialize all of the Outer nodes
+	     */
+	    curNode = 1;
+	    foreach(tlistP, lnext(tlist))
+		{
+		    TargetEntry *tle = lfirst(tlistP);
+		    
+		    resVect[curNode] = ExecEvalIter((Iter*)tle->expr,
+						    econtext,
+						    &isNullVect[curNode],
+						    &isDone);
+		    if (isDone)
+			isNullVect[curNode] = alwaysDone[curNode] = true;
+		    else
+			alwaysDone[curNode] = false;
+		    
+		    curNode++;
+		}
+	    
+	    /*
+	     * Initialize the inner node
+	     */
+	    resVect[0] = ExecEvalIter((Iter*)fjNode->fj_innerNode->expr,
+				      econtext,
+				      &isNullVect[0],
+				      &isDone);
+	    if (isDone)
+		isNullVect[0] = alwaysDone[0] = true;
+	    else
+		alwaysDone[0] = false;
+	    
+	    /*
+	     * Mark the Fjoin as initialized now.
+	     */
+	    fjNode->fj_initialized = TRUE;
+	    
+	    /*
+	     * If the inner node is always done, then we are done for now
+	     */
+	    if (isDone)
+		return;
+	}
+    else
+	{
+	    /*
+	     * If we're already initialized, all we need to do is get the
+	     * next inner result and pair it up with the existing outer node
+	     * result vector.  Watch out for the degenerate case, where the
+	     * inner node never returns results.
+	     */
+	    
+	    /*
+	     * Fill in nulls for every function that is always done.
+	     */
+	    for (curNode=fjNode->fj_nNodes-1; curNode >= 0; curNode--)
+		isNullVect[curNode] = alwaysDone[curNode];
+	    
+	    if (alwaysDone[0] == true)
+		{
+		    *fj_isDone = FjoinBumpOuterNodes(tlist,
+						     econtext,
+						     resVect,
+						     isNullVect);
+		    return;
+		}
+	    else
+		resVect[0] = ExecEvalIter((Iter*)fjNode->fj_innerNode->expr,
+					  econtext,
+					  &isNullVect[0],
+					  &isDone);
+	}
+    
+    /*
+     * if the inner node is done
+     */
+    if (isDone)
+	{
+	    *fj_isDone = FjoinBumpOuterNodes(tlist,
+					     econtext,
+					     resVect,
+					     isNullVect);
+	    if (*fj_isDone)
+		return;
+	    
+	    resVect[0] = ExecEvalIter((Iter*)fjNode->fj_innerNode->expr,
+				      econtext,
+				      &isNullVect[0],
+				      &isDone);
+	    
+	}
+#endif
+    return;
+}
+
+bool
+FjoinBumpOuterNodes(TargetEntry *tlist,
+		    ExprContext *econtext,
+		    DatumPtr results,
+		    char *nulls)
+{
+#ifdef SETS_FIXED
+    bool   funcIsDone = true;
+    Fjoin  *fjNode    = tlist->fjoin;
+    char *alwaysDone = fjNode->fj_alwaysDone;
+    List   *outerList  = lnext(tlist);
+    List   *trailers   = lnext(tlist);
+    int    trailNode  = 1;
+    int    curNode    = 1;
+    
+    /*
+     * Run through list of functions until we get to one that isn't yet
+     * done returning values.  Watch out for funcs that are always done.
+     */
+    while ((funcIsDone == true) && (outerList != NIL))
+	{
+	    TargetEntry *tle = lfirst(outerList);
+	    
+	    if (alwaysDone[curNode] == true)
+		nulls[curNode] = 'n';
+	    else
+		results[curNode] = ExecEvalIter((Iter)tle->expr,
+						econtext,
+						&nulls[curNode],
+						&funcIsDone);
+	    curNode++;
+	    outerList = lnext(outerList);
+	}
+    
+    /*
+     * If every function is done, then we are done flattening.
+     * Mark the Fjoin node unitialized, it is time to get the
+     * next tuple from the plan and redo all of the flattening.
+     */
+    if (funcIsDone)
+	{
+	    set_fj_initialized(fjNode, false);
+	    return (true);
+	}
+    
+    /*
+     * We found a function that wasn't done.  Now re-run every function
+     * before it.  As usual watch out for functions that are always done.
+     */
+    trailNode = 1;
+    while (trailNode != curNode-1)
+	{
+	    TargetEntry *tle = lfirst(trailers);
+	    
+	    if (alwaysDone[trailNode] != true)
+		results[trailNode] = ExecEvalIter((Iter)tle->expr,
+						  econtext,
+						  &nulls[trailNode],
+						  &funcIsDone);
+	    trailNode++;
+	    trailers = lnext(trailers);
+	}
+    return false;
+#endif
+    return false;
+}