Simplify parse representation of savepoint commands

Instead of embedding the savepoint name in a list and then requiring
complex code to unpack it, just add another struct field to store it
directly.
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>

src/backend/access/transam/xact.c

@@ -3908,13 +3908,11 @@ DefineSavepoint(const char *name)
  * As above, we don't actually do anything here except change blockState.
  */
 void
-ReleaseSavepoint(List *options)
+ReleaseSavepoint(const char *name)
 {
 	TransactionState s = CurrentTransactionState;
 	TransactionState target,
 				xact;
-	ListCell   *cell;
-	char	   *name = NULL;
 
 	/*
 	 * Workers synchronize transaction state at the beginning of each parallel
@@ -3978,16 +3976,6 @@ ReleaseSavepoint(List *options)
 			break;
 	}
 
-	foreach(cell, options)
-	{
-		DefElem    *elem = lfirst(cell);
-
-		if (strcmp(elem->defname, "savepoint_name") == 0)
-			name = strVal(elem->arg);
-	}
-
-	Assert(PointerIsValid(name));
-
 	for (target = s; PointerIsValid(target); target = target->parent)
 	{
 		if (PointerIsValid(target->name) && strcmp(target->name, name) == 0)
@@ -4029,13 +4017,11 @@ ReleaseSavepoint(List *options)
  * As above, we don't actually do anything here except change blockState.
  */
 void
-RollbackToSavepoint(List *options)
+RollbackToSavepoint(const char *name)
 {
 	TransactionState s = CurrentTransactionState;
 	TransactionState target,
 				xact;
-	ListCell   *cell;
-	char	   *name = NULL;
 
 	/*
 	 * Workers synchronize transaction state at the beginning of each parallel
@@ -4099,16 +4085,6 @@ RollbackToSavepoint(List *options)
 			break;
 	}
 
-	foreach(cell, options)
-	{
-		DefElem    *elem = lfirst(cell);
-
-		if (strcmp(elem->defname, "savepoint_name") == 0)
-			name = strVal(elem->arg);
-	}
-
-	Assert(PointerIsValid(name));
-
 	for (target = s; PointerIsValid(target); target = target->parent)
 	{
 		if (PointerIsValid(target->name) && strcmp(target->name, name) == 0)

src/backend/nodes/copyfuncs.c

@@ -3602,6 +3602,7 @@ _copyTransactionStmt(const TransactionStmt *from)
 
 	COPY_SCALAR_FIELD(kind);
 	COPY_NODE_FIELD(options);
+	COPY_STRING_FIELD(savepoint_name);
 	COPY_STRING_FIELD(gid);
 
 	return newnode;

src/backend/nodes/equalfuncs.c

@@ -1513,6 +1513,7 @@ _equalTransactionStmt(const TransactionStmt *a, const TransactionStmt *b)
 {
 	COMPARE_SCALAR_FIELD(kind);
 	COMPARE_NODE_FIELD(options);
+	COMPARE_STRING_FIELD(savepoint_name);
 	COMPARE_STRING_FIELD(gid);
 
 	return true;

src/backend/parser/gram.y

@@ -9876,40 +9876,35 @@ TransactionStmt:
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_SAVEPOINT;
-					n->options = list_make1(makeDefElem("savepoint_name",
-														(Node *)makeString($2), @1));
+					n->savepoint_name = $2;
 					$$ = (Node *)n;
 				}
 			| RELEASE SAVEPOINT ColId
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_RELEASE;
-					n->options = list_make1(makeDefElem("savepoint_name",
-														(Node *)makeString($3), @1));
+					n->savepoint_name = $3;
 					$$ = (Node *)n;
 				}
 			| RELEASE ColId
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_RELEASE;
-					n->options = list_make1(makeDefElem("savepoint_name",
-														(Node *)makeString($2), @1));
+					n->savepoint_name = $2;
 					$$ = (Node *)n;
 				}
 			| ROLLBACK opt_transaction TO SAVEPOINT ColId
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_ROLLBACK_TO;
-					n->options = list_make1(makeDefElem("savepoint_name",
-														(Node *)makeString($5), @1));
+					n->savepoint_name = $5;
 					$$ = (Node *)n;
 				}
 			| ROLLBACK opt_transaction TO ColId
 				{
 					TransactionStmt *n = makeNode(TransactionStmt);
 					n->kind = TRANS_STMT_ROLLBACK_TO;
-					n->options = list_make1(makeDefElem("savepoint_name",
-														(Node *)makeString($4), @1));
+					n->savepoint_name = $4;
 					$$ = (Node *)n;
 				}
 			| PREPARE TRANSACTION Sconst

src/backend/tcop/utility.c

@@ -469,34 +469,18 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 						break;
 
 					case TRANS_STMT_SAVEPOINT:
-						{
-							ListCell   *cell;
-							char	   *name = NULL;
-
 						RequireTransactionBlock(isTopLevel, "SAVEPOINT");
-
-							foreach(cell, stmt->options)
-							{
-								DefElem    *elem = lfirst(cell);
-
-								if (strcmp(elem->defname, "savepoint_name") == 0)
-									name = strVal(elem->arg);
-							}
-
-							Assert(PointerIsValid(name));
-
-							DefineSavepoint(name);
-						}
+						DefineSavepoint(stmt->savepoint_name);
 						break;
 
 					case TRANS_STMT_RELEASE:
 						RequireTransactionBlock(isTopLevel, "RELEASE SAVEPOINT");
-						ReleaseSavepoint(stmt->options);
+						ReleaseSavepoint(stmt->savepoint_name);
 						break;
 
 					case TRANS_STMT_ROLLBACK_TO:
 						RequireTransactionBlock(isTopLevel, "ROLLBACK TO SAVEPOINT");
-						RollbackToSavepoint(stmt->options);
+						RollbackToSavepoint(stmt->savepoint_name);
 
 						/*
 						 * CommitTransactionCommand is in charge of

src/include/access/xact.h

@@ -354,9 +354,9 @@ extern bool PrepareTransactionBlock(const char *gid);
 extern void UserAbortTransactionBlock(void);
 extern void BeginImplicitTransactionBlock(void);
 extern void EndImplicitTransactionBlock(void);
-extern void ReleaseSavepoint(List *options);
+extern void ReleaseSavepoint(const char *name);
 extern void DefineSavepoint(const char *name);
-extern void RollbackToSavepoint(List *options);
+extern void RollbackToSavepoint(const char *name);
 extern void BeginInternalSubTransaction(const char *name);
 extern void ReleaseCurrentSubTransaction(void);
 extern void RollbackAndReleaseCurrentSubTransaction(void);

src/include/nodes/parsenodes.h

@@ -2966,7 +2966,8 @@ typedef struct TransactionStmt
 {
 	NodeTag		type;
 	TransactionStmtKind kind;	/* see above */
-	List	   *options;		/* for BEGIN/START and savepoint commands */
+	List	   *options;		/* for BEGIN/START commands */
+	char	   *savepoint_name;	/* for savepoint commands */
 	char	   *gid;			/* for two-phase-commit related commands */
 } TransactionStmt;