Implement the DO statement to support execution of PL code without having

to create a function for it.

Procedural languages now have an additional entry point, namely a function
to execute an inline code block.  This seemed a better design than trying
to hide the transient-ness of the code from the PL.  As of this patch, only
plpgsql has an inline handler, but probably people will soon write handlers
for the other standard PLs.

In passing, remove the long-dead LANCOMPILER option of CREATE LANGUAGE.

Petr Jelinek

1 files changed, 75 insertions, 8 deletions

diff --git a/src/backend/commands/proclang.c b/src/backend/commands/proclang.c
index 27af379d7e1..2a5bcd6363d 100644
--- a/src/backend/commands/proclang.c
+++ b/src/backend/commands/proclang.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/proclang.c,v 1.86 2009/07/12 17:12:33 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/proclang.c,v 1.87 2009/09/22 23:43:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -44,12 +44,14 @@ typedef struct
 	bool		tmpltrusted;	/* trusted? */
 	bool		tmpldbacreate;	/* db owner allowed to create? */
 	char	   *tmplhandler;	/* name of handler function */
+	char	   *tmplinline;		/* name of anonymous-block handler, or NULL */
 	char	   *tmplvalidator;	/* name of validator function, or NULL */
 	char	   *tmpllibrary;	/* path of shared library */
 } PLTemplate;
 
 static void create_proc_lang(const char *languageName,
-				 Oid languageOwner, Oid handlerOid, Oid valOid, bool trusted);
+				 Oid languageOwner, Oid handlerOid, Oid inlineOid,
+				 Oid valOid, bool trusted);
 static PLTemplate *find_language_template(const char *languageName);
 static void AlterLanguageOwner_internal(HeapTuple tup, Relation rel,
 							Oid newOwnerId);
@@ -65,6 +67,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 	char	   *languageName;
 	PLTemplate *pltemplate;
 	Oid			handlerOid,
+				inlineOid,
 				valOid;
 	Oid			funcrettype;
 	Oid			funcargtypes[1];
@@ -155,6 +158,44 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 		}
 
 		/*
+		 * Likewise for the anonymous block handler, if required;
+		 * but we don't care about its return type.
+		 */
+		if (pltemplate->tmplinline)
+		{
+			funcname = SystemFuncName(pltemplate->tmplinline);
+			funcargtypes[0] = INTERNALOID;
+			inlineOid = LookupFuncName(funcname, 1, funcargtypes, true);
+			if (!OidIsValid(inlineOid))
+			{
+				inlineOid = ProcedureCreate(pltemplate->tmplinline,
+											PG_CATALOG_NAMESPACE,
+											false, /* replace */
+											false, /* returnsSet */
+											VOIDOID,
+											ClanguageId,
+											F_FMGR_C_VALIDATOR,
+											pltemplate->tmplinline,
+											pltemplate->tmpllibrary,
+											false, /* isAgg */
+											false, /* isWindowFunc */
+											false, /* security_definer */
+											true, /* isStrict */
+											PROVOLATILE_VOLATILE,
+											buildoidvector(funcargtypes, 1),
+											PointerGetDatum(NULL),
+											PointerGetDatum(NULL),
+											PointerGetDatum(NULL),
+											NIL,
+											PointerGetDatum(NULL),
+											1,
+											0);
+			}
+		}
+		else
+			inlineOid = InvalidOid;
+
+		/*
 		 * Likewise for the validator, if required; but we don't care about
 		 * its return type.
 		 */
@@ -177,7 +218,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 										 false, /* isAgg */
 										 false, /* isWindowFunc */
 										 false, /* security_definer */
-										 false, /* isStrict */
+										 true, /* isStrict */
 										 PROVOLATILE_VOLATILE,
 										 buildoidvector(funcargtypes, 1),
 										 PointerGetDatum(NULL),
@@ -193,8 +234,8 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 			valOid = InvalidOid;
 
 		/* ok, create it */
-		create_proc_lang(languageName, GetUserId(), handlerOid, valOid,
-						 pltemplate->tmpltrusted);
+		create_proc_lang(languageName, GetUserId(), handlerOid, inlineOid,
+						 valOid, pltemplate->tmpltrusted);
 	}
 	else
 	{
@@ -246,6 +287,16 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 						 NameListToString(stmt->plhandler))));
 		}
 
+		/* validate the inline function */
+		if (stmt->plinline)
+		{
+			funcargtypes[0] = INTERNALOID;
+			inlineOid = LookupFuncName(stmt->plinline, 1, funcargtypes, false);
+			/* return value is ignored, so we don't check the type */
+		}
+		else
+			inlineOid = InvalidOid;
+
 		/* validate the validator function */
 		if (stmt->plvalidator)
 		{
@@ -257,8 +308,8 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 			valOid = InvalidOid;
 
 		/* ok, create it */
-		create_proc_lang(languageName, GetUserId(), handlerOid, valOid,
-						 stmt->pltrusted);
+		create_proc_lang(languageName, GetUserId(), handlerOid, inlineOid,
+						 valOid, stmt->pltrusted);
 	}
 }
 
@@ -267,7 +318,8 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
  */
 static void
 create_proc_lang(const char *languageName,
-				 Oid languageOwner, Oid handlerOid, Oid valOid, bool trusted)
+				 Oid languageOwner, Oid handlerOid, Oid inlineOid,
+				 Oid valOid, bool trusted)
 {
 	Relation	rel;
 	TupleDesc	tupDesc;
@@ -293,6 +345,7 @@ create_proc_lang(const char *languageName,
 	values[Anum_pg_language_lanispl - 1] = BoolGetDatum(true);
 	values[Anum_pg_language_lanpltrusted - 1] = BoolGetDatum(trusted);
 	values[Anum_pg_language_lanplcallfoid - 1] = ObjectIdGetDatum(handlerOid);
+	values[Anum_pg_language_laninline - 1] = ObjectIdGetDatum(inlineOid);
 	values[Anum_pg_language_lanvalidator - 1] = ObjectIdGetDatum(valOid);
 	nulls[Anum_pg_language_lanacl - 1] = true;
 
@@ -321,6 +374,15 @@ create_proc_lang(const char *languageName,
 	referenced.objectSubId = 0;
 	recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
 
+	/* dependency on the inline handler function, if any */
+	if (OidIsValid(inlineOid))
+	{
+		referenced.classId = ProcedureRelationId;
+		referenced.objectId = inlineOid;
+		referenced.objectSubId = 0;
+		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+	}
+
 	/* dependency on the validator function, if any */
 	if (OidIsValid(valOid))
 	{
@@ -371,6 +433,11 @@ find_language_template(const char *languageName)
 		if (!isnull)
 			result->tmplhandler = TextDatumGetCString(datum);
 
+		datum = heap_getattr(tup, Anum_pg_pltemplate_tmplinline,
+							 RelationGetDescr(rel), &isnull);
+		if (!isnull)
+			result->tmplinline = TextDatumGetCString(datum);
+
 		datum = heap_getattr(tup, Anum_pg_pltemplate_tmplvalidator,
 							 RelationGetDescr(rel), &isnull);
 		if (!isnull)