The cstring datatype can now be copied, passed around, etc. The typlen

value '-2' is used to indicate a variable-width type whose width is
computed as strlen(datum)+1.  Everything that looks at typlen is updated
except for array support, which Joe Conway is working on; at the moment
it wouldn't work to try to create an array of cstring.

Author: tglsfdc

doc/src/sgml/catalogs.sgml

@@ -1,6 +1,6 @@
 <!--
  Documentation of the system catalogs, directed toward PostgreSQL developers
- $Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.53 2002/08/13 17:22:08 petere Exp $
+ $Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.54 2002/08/24 15:00:45 tgl Exp $
  -->
 
 <chapter id="catalogs">
@@ -3173,7 +3173,13 @@
       <entry>typlen</entry>
       <entry><type>int2</type></entry>
       <entry></entry>
-      <entry>Length of the storage representation of the type, -1 if variable length</entry>
+      <entry>
+       For a fixed-size type, <structfield>typlen</structfield> is the number
+       of bytes in the internal representation of the type.  But for a
+       variable-length type, <structfield>typlen</structfield> is negative.
+       -1 indicates a <quote>varlena</> type (one that has a length word),
+       -2 indicates a null-terminated C string.
+      </entry>
      </row>
 
      <row>
@@ -3325,7 +3331,7 @@
       <entry><type>char</type></entry>
       <entry></entry>
       <entry><para>
-       <structfield>typstorage</structfield> tells for variable-length
+       <structfield>typstorage</structfield> tells for varlena
        types (those with <structfield>typlen</structfield> = -1) if
        the type is prepared for toasting and what the default strategy
        for attributes of this type should be.

src/backend/access/common/heaptuple.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.78 2002/07/20 05:16:56 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/common/heaptuple.c,v 1.79 2002/08/24 15:00:45 tgl Exp $
  *
  * NOTES
  *	  The old interface functions have been converted to macros
@@ -48,7 +48,7 @@ ComputeDataSize(TupleDesc tupleDesc,
 		if (nulls[i] != ' ')
 			continue;
 
-		data_length = att_align(data_length, att[i]->attlen, att[i]->attalign);
+		data_length = att_align(data_length, att[i]->attalign);
 		data_length = att_addlength(data_length, att[i]->attlen, value[i]);
 	}
 
@@ -69,7 +69,7 @@ DataFill(char *data,
 {
 	bits8	   *bitP = 0;
 	int			bitmask = 0;
-	uint32		data_length;
+	Size		data_length;
 	int			i;
 	int			numberOfAttributes = tupleDesc->natts;
 	Form_pg_attribute *att = tupleDesc->attrs;
@@ -105,12 +105,13 @@ DataFill(char *data,
 		}
 
 		/* XXX we are aligning the pointer itself, not the offset */
-		data = (char *) att_align((long) data, att[i]->attlen, att[i]->attalign);
+		data = (char *) att_align((long) data, att[i]->attalign);
 
 		if (att[i]->attbyval)
 		{
 			/* pass-by-value */
 			store_att_byval(data, value[i], att[i]->attlen);
+			data_length = att[i]->attlen;
 		}
 		else if (att[i]->attlen == -1)
 		{
@@ -123,15 +124,22 @@ DataFill(char *data,
 			data_length = VARATT_SIZE(DatumGetPointer(value[i]));
 			memcpy(data, DatumGetPointer(value[i]), data_length);
 		}
+		else if (att[i]->attlen == -2)
+		{
+			/* cstring */
+			*infomask |= HEAP_HASVARLENA;
+			data_length = strlen(DatumGetCString(value[i])) + 1;
+			memcpy(data, DatumGetPointer(value[i]), data_length);
+		}
 		else
 		{
 			/* fixed-length pass-by-reference */
-			Assert(att[i]->attlen >= 0);
-			memcpy(data, DatumGetPointer(value[i]),
-				   (size_t) (att[i]->attlen));
+			Assert(att[i]->attlen > 0);
+			data_length = att[i]->attlen;
+			memcpy(data, DatumGetPointer(value[i]), data_length);
 		}
 
-		data = (char *) att_addlength((long) data, att[i]->attlen, value[i]);
+		data += data_length;
 	}
 }
 
@@ -235,17 +243,16 @@ nocachegetattr(HeapTuple tuple,
 		if (att[attnum]->attcacheoff != -1)
 		{
 			return fetchatt(att[attnum],
-				  (char *) tup + tup->t_hoff + att[attnum]->attcacheoff);
+							(char *) tup + tup->t_hoff +
+							att[attnum]->attcacheoff);
 		}
 #endif
 	}
 	else
 	{
 		/*
 		 * there's a null somewhere in the tuple
-		 */
-
-		/*
+		 *
 		 * check to see if desired att is null
 		 */
 
@@ -346,11 +353,7 @@ nocachegetattr(HeapTuple tuple,
 			  (HeapTupleNoNulls(tuple) || !att_isnull(j, bp)) &&
 			  (HeapTupleAllFixed(tuple) || att[j]->attlen > 0)); j++)
 		{
-			/*
-			 * Fix me when going to a machine with more than a four-byte
-			 * word!
-			 */
-			off = att_align(off, att[j]->attlen, att[j]->attalign);
+			off = att_align(off, att[j]->attalign);
 
 			att[j]->attcacheoff = off;
 
@@ -391,19 +394,19 @@ nocachegetattr(HeapTuple tuple,
 				off = att[i]->attcacheoff;
 			else
 			{
-				off = att_align(off, att[i]->attlen, att[i]->attalign);
+				off = att_align(off, att[i]->attalign);
 
 				if (usecache)
 					att[i]->attcacheoff = off;
 			}
 
 			off = att_addlength(off, att[i]->attlen, tp + off);
 
-			if (usecache && att[i]->attlen == -1)
+			if (usecache && att[i]->attlen <= 0)
 				usecache = false;
 		}
 
-		off = att_align(off, att[attnum]->attlen, att[attnum]->attalign);
+		off = att_align(off, att[attnum]->attalign);
 
 		return fetchatt(att[attnum], tp + off);
 	}

src/backend/access/common/indextuple.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/common/indextuple.c,v 1.57 2002/06/20 20:29:24 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/common/indextuple.c,v 1.58 2002/08/24 15:00:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -64,7 +64,7 @@ index_formtuple(TupleDesc tupleDescriptor,
 		untoasted_free[i] = false;
 
 		/* Do nothing if value is NULL or not of varlena type */
-		if (null[i] != ' ' || att->attlen >= 0)
+		if (null[i] != ' ' || att->attlen != -1)
 			continue;
 
 		/*
@@ -243,9 +243,10 @@ nocache_index_getattr(IndexTuple tup,
 #endif
 	}
 	else
-	{							/* there's a null somewhere in the tuple */
-
+	{
 		/*
+		 * there's a null somewhere in the tuple
+		 *
 		 * check to see if desired att is null
 		 */
 
@@ -291,8 +292,9 @@ nocache_index_getattr(IndexTuple tup,
 
 	tp = (char *) tup + data_off;
 
-	/* now check for any non-fixed length attrs before our attribute */
-
+	/*
+	 * now check for any non-fixed length attrs before our attribute
+	 */
 	if (!slow)
 	{
 		if (att[attnum]->attcacheoff != -1)
@@ -305,11 +307,13 @@ nocache_index_getattr(IndexTuple tup,
 			int			j;
 
 			for (j = 0; j < attnum; j++)
+			{
 				if (att[j]->attlen <= 0)
 				{
 					slow = true;
 					break;
 				}
+			}
 		}
 	}
 
@@ -337,12 +341,7 @@ nocache_index_getattr(IndexTuple tup,
 
 		for (; j <= attnum; j++)
 		{
-			/*
-			 * Fix me when going to a machine with more than a four-byte
-			 * word!
-			 */
-
-			off = att_align(off, att[j]->attlen, att[j]->attalign);
+			off = att_align(off, att[j]->attalign);
 
 			att[j]->attcacheoff = off;
 
@@ -377,22 +376,19 @@ nocache_index_getattr(IndexTuple tup,
 				off = att[i]->attcacheoff;
 			else
 			{
-				off = att_align(off, att[i]->attlen, att[i]->attalign);
+				off = att_align(off, att[i]->attalign);
 
 				if (usecache)
 					att[i]->attcacheoff = off;
 			}
 
-			if (att[i]->attlen == -1)
-			{
-				off += VARSIZE(tp + off);
+			off = att_addlength(off, att[i]->attlen, tp + off);
+
+			if (usecache && att[i]->attlen <= 0)
 				usecache = false;
-			}
-			else
-				off += att[i]->attlen;
 		}
 
-		off = att_align(off, att[attnum]->attlen, att[attnum]->attalign);
+		off = att_align(off, att[attnum]->attalign);
 
 		return fetchatt(att[attnum], tp + off);
 	}

src/backend/access/common/printtup.c

@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/common/printtup.c,v 1.63 2002/08/22 00:01:41 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/common/printtup.c,v 1.64 2002/08/24 15:00:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -457,9 +457,15 @@ printtup_internal(HeapTuple tuple, TupleDesc typeinfo, DestReceiver *self)
 		}
 		else
 		{
-			/* fixed size */
+			/* fixed size or cstring */
 			attr = origattr;
 			len = typeinfo->attrs[i]->attlen;
+			if (len <= 0)
+			{
+				/* it's a cstring */
+				Assert(len == -2 && !typeinfo->attrs[i]->attbyval);
+				len = strlen(DatumGetCString(attr)) + 1;
+			}
 			pq_sendint(&buf, len, sizeof(int32));
 			if (typeinfo->attrs[i]->attbyval)
 			{

src/backend/catalog/pg_type.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_type.c,v 1.78 2002/08/15 16:36:01 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_type.c,v 1.79 2002/08/24 15:00:46 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -157,14 +157,25 @@ TypeCreate(const char *typeName,
 	int			i;
 
 	/*
-	 * validate size specifications: either positive (fixed-length) or -1
-	 * (variable-length).
+	 * We assume that the caller validated the arguments individually,
+	 * but did not check for bad combinations.
+	 *
+	 * Validate size specifications: either positive (fixed-length) or -1
+	 * (varlena) or -2 (cstring).  Pass-by-value types must have a fixed
+	 * length not more than sizeof(Datum).
 	 */
-	if (!(internalSize > 0 || internalSize == -1))
+	if (!(internalSize > 0 ||
+		  internalSize == -1 ||
+		  internalSize == -2))
+		elog(ERROR, "TypeCreate: invalid type internal size %d",
+			 internalSize);
+	if (passedByValue &&
+		(internalSize <= 0 || internalSize > (int16) sizeof(Datum)))
 		elog(ERROR, "TypeCreate: invalid type internal size %d",
 			 internalSize);
 
-	if (internalSize != -1 && storage != 'p')
+	/* Only varlena types can be toasted */
+	if (storage != 'p' && internalSize != -1)
 		elog(ERROR, "TypeCreate: fixed size types must have storage PLAIN");
 
 	/*