1 files changed, 256 insertions, 0 deletions
diff --git a/src/backend/access/gin/ginscan.c b/src/backend/access/gin/ginscan.c
new file mode 100644
index 00000000000..b641b82e662
--- /dev/null
+++ b/src/backend/access/gin/ginscan.c
@@ -0,0 +1,256 @@
+/*-------------------------------------------------------------------------
+ *
+ * ginscan.c
+ *    routines to manage scans inverted index relations
+ *
+ *
+ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *          $PostgreSQL: pgsql/src/backend/access/gin/ginscan.c,v 1.1 2006/05/02 11:28:54 teodor Exp $
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+#include "access/genam.h"
+#include "access/gin.h"
+#include "access/heapam.h"
+#include "catalog/index.h"
+#include "miscadmin.h"
+#include "storage/freespace.h"
+#include "utils/memutils.h"
+
+
+Datum 
+ginbeginscan(PG_FUNCTION_ARGS) {
+	Relation    rel = (Relation) PG_GETARG_POINTER(0);
+	int         keysz = PG_GETARG_INT32(1);
+	ScanKey     scankey = (ScanKey) PG_GETARG_POINTER(2);
+	IndexScanDesc scan;
+
+	scan = RelationGetIndexScan(rel, keysz, scankey);
+
+	PG_RETURN_POINTER(scan);
+}
+
+static void
+fillScanKey( GinState *ginstate, GinScanKey key, Datum query, 
+				Datum *entryValues, uint32 nEntryValues, StrategyNumber strategy ) {
+	uint32 i,j;
+
+	key->nentries = nEntryValues;
+	key->entryRes = (bool*)palloc0( sizeof(bool) * nEntryValues ); 
+	key->scanEntry = (GinScanEntry) palloc( sizeof(GinScanEntryData) * nEntryValues );
+	key->strategy = strategy;
+	key->query = query;
+	key->firstCall= TRUE;
+	ItemPointerSet( &(key->curItem), InvalidBlockNumber, InvalidOffsetNumber );
+
+	for(i=0; i<nEntryValues; i++) {
+		key->scanEntry[i].pval = key->entryRes + i;
+		key->scanEntry[i].entry = entryValues[i];
+		ItemPointerSet( &(key->scanEntry[i].curItem), InvalidBlockNumber, InvalidOffsetNumber );
+		key->scanEntry[i].offset = InvalidOffsetNumber;
+		key->scanEntry[i].buffer = InvalidBuffer;
+		key->scanEntry[i].list = NULL;
+		key->scanEntry[i].nlist = 0;
+
+		/* link to the equals entry in current scan key */
+		key->scanEntry[i].master = NULL;
+		for( j=0; j<i; j++)
+			if ( compareEntries( ginstate, entryValues[i], entryValues[j] ) == 0 ) {
+				key->scanEntry[i].master = key->scanEntry + j;
+				break;
+			}
+	}
+}
+
+static void
+resetScanKeys(GinScanKey keys, uint32 nkeys) {
+	uint32	i, j;
+
+	if ( keys == NULL )
+		return;
+
+	for(i=0;i<nkeys;i++) {
+		GinScanKey key = keys + i;
+
+		key->firstCall = TRUE;
+		ItemPointerSet( &(key->curItem), InvalidBlockNumber, InvalidOffsetNumber );
+
+		for(j=0;j<key->nentries;j++) {
+			if ( key->scanEntry[j].buffer != InvalidBuffer )
+				ReleaseBuffer( key->scanEntry[i].buffer );
+
+			ItemPointerSet( &(key->scanEntry[j].curItem), InvalidBlockNumber, InvalidOffsetNumber );
+			key->scanEntry[j].offset = InvalidOffsetNumber;
+			key->scanEntry[j].buffer = InvalidBuffer;
+			key->scanEntry[j].list = NULL;
+			key->scanEntry[j].nlist = 0;
+		}
+	}
+}
+
+static void
+freeScanKeys(GinScanKey keys, uint32 nkeys, bool removeRes) {
+	uint32	i, j;
+
+	if ( keys == NULL )
+		return;
+
+	for(i=0;i<nkeys;i++) {
+		GinScanKey key = keys + i;
+
+		for(j=0;j<key->nentries;j++) {
+			if ( key->scanEntry[j].buffer != InvalidBuffer )
+				ReleaseBuffer( key->scanEntry[j].buffer );
+			if ( removeRes && key->scanEntry[j].list ) 
+				pfree(key->scanEntry[j].list);
+		}
+
+		if ( removeRes )
+			pfree(key->entryRes);
+		pfree(key->scanEntry);
+	}
+	
+	pfree(keys);
+}
+
+void
+newScanKey( IndexScanDesc scan ) {
+	ScanKey     scankey = scan->keyData;
+	GinScanOpaque so = (GinScanOpaque) scan->opaque;
+	int i;
+	uint32 nkeys = 0;
+
+	so->keys = (GinScanKey) palloc( scan->numberOfKeys * sizeof(GinScanKeyData) );
+
+	for(i=0; i<scan->numberOfKeys; i++) {
+		Datum*	entryValues;
+		uint32	nEntryValues;
+
+		if ( scankey[i].sk_flags & SK_ISNULL )
+			elog(ERROR, "Gin doesn't support NULL as scan key");
+		Assert( scankey[i].sk_attno == 1 );
+
+		entryValues = (Datum*)DatumGetPointer(
+							FunctionCall3(
+								&so->ginstate.extractQueryFn,
+								scankey[i].sk_argument,
+								PointerGetDatum( &nEntryValues ),
+								UInt16GetDatum(scankey[i].sk_strategy)
+							)
+						);
+		if ( entryValues==NULL || nEntryValues == 0 )
+			/* full scan... */
+			continue;
+
+		fillScanKey( &so->ginstate, &(so->keys[nkeys]), scankey[i].sk_argument,
+				entryValues, nEntryValues, scankey[i].sk_strategy );
+		nkeys++;
+	}
+
+	so->nkeys = nkeys;
+
+	if ( so->nkeys == 0 )
+		elog(ERROR, "Gin doesn't support full scan due to it's awful inefficiency");
+}
+
+Datum
+ginrescan(PG_FUNCTION_ARGS) {
+	IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
+	ScanKey     scankey = (ScanKey) PG_GETARG_POINTER(1);
+	GinScanOpaque	so;
+
+	so = (GinScanOpaque) scan->opaque;
+
+	if ( so == NULL ) {
+		/* if called from ginbeginscan */
+		so = (GinScanOpaque)palloc( sizeof(GinScanOpaqueData) );
+		so->tempCtx = AllocSetContextCreate(CurrentMemoryContext,
+								"Gin scan temporary context",
+								ALLOCSET_DEFAULT_MINSIZE,
+								ALLOCSET_DEFAULT_INITSIZE,
+								ALLOCSET_DEFAULT_MAXSIZE);
+		initGinState(&so->ginstate, scan->indexRelation);
+		scan->opaque = so;
+	} else {
+		freeScanKeys(so->keys, so->nkeys, TRUE);
+		freeScanKeys(so->markPos, so->nkeys, FALSE);
+	}
+
+	so->markPos=so->keys=NULL;
+
+	if ( scankey && scan->numberOfKeys > 0 ) {
+		memmove(scan->keyData, scankey,
+			scan->numberOfKeys * sizeof(ScanKeyData));
+	}
+
+	PG_RETURN_VOID();
+}
+
+
+Datum
+ginendscan(PG_FUNCTION_ARGS) {
+	IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
+    GinScanOpaque   so = (GinScanOpaque) scan->opaque;
+
+	if ( so != NULL ) {
+		freeScanKeys(so->keys, so->nkeys, TRUE); 
+		freeScanKeys(so->markPos, so->nkeys, FALSE); 
+
+		MemoryContextDelete(so->tempCtx);
+
+		pfree(so);
+	}
+
+	PG_RETURN_VOID();
+}
+
+static GinScanKey
+copyScanKeys( GinScanKey keys, uint32 nkeys ) {
+	GinScanKey	newkeys;
+	uint32 i, j;
+
+	newkeys = (GinScanKey)palloc( sizeof(GinScanKeyData) * nkeys );
+	memcpy( newkeys, keys, sizeof(GinScanKeyData) * nkeys );
+
+	for(i=0;i<nkeys;i++) {
+		newkeys[i].scanEntry = (GinScanEntry)palloc(sizeof(GinScanEntryData) * keys[i].nentries );
+		memcpy( newkeys[i].scanEntry, keys[i].scanEntry, sizeof(GinScanEntryData) * keys[i].nentries );
+
+		for(j=0;j<keys[i].nentries; j++) { 
+			if ( keys[i].scanEntry[j].buffer != InvalidBuffer )
+				IncrBufferRefCount( keys[i].scanEntry[j].buffer );
+			if ( keys[i].scanEntry[j].master ) {
+				int masterN = keys[i].scanEntry[j].master - keys[i].scanEntry;
+				newkeys[i].scanEntry[j].master = newkeys[i].scanEntry + masterN;
+			}
+		}
+	}
+
+	return newkeys;
+}
+
+Datum 
+ginmarkpos(PG_FUNCTION_ARGS) {
+	IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
+	GinScanOpaque   so = (GinScanOpaque) scan->opaque;
+
+	freeScanKeys(so->markPos, so->nkeys, FALSE);
+	so->markPos = copyScanKeys( so->keys, so->nkeys );
+
+	PG_RETURN_VOID();
+}
+
+Datum 
+ginrestrpos(PG_FUNCTION_ARGS) {
+	IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0);
+	GinScanOpaque   so = (GinScanOpaque) scan->opaque;
+
+	freeScanKeys(so->keys, so->nkeys, FALSE);
+	so->keys = copyScanKeys( so->markPos, so->nkeys );
+
+	PG_RETURN_VOID();
+}