4 files changed, 239 insertions, 0 deletions
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 92593526725..1774c56ae31 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1008,6 +1008,79 @@ typedef struct DomainConstraintState
 	ExprState  *check_exprstate;	/* check_expr's eval state, or NULL */
 } DomainConstraintState;
 
+/*
+ * State for JsonExpr evaluation, too big to inline.
+ *
+ * This contains the information going into and coming out of the
+ * EEOP_JSONEXPR_PATH eval step.
+ */
+typedef struct JsonExprState
+{
+	/* original expression node */
+	JsonExpr   *jsexpr;
+
+	/* value/isnull for formatted_expr */
+	NullableDatum formatted_expr;
+
+	/* value/isnull for pathspec */
+	NullableDatum pathspec;
+
+	/* JsonPathVariable entries for passing_values */
+	List	   *args;
+
+	/*
+	 * Output variables that drive the EEOP_JUMP_IF_NOT_TRUE steps that are
+	 * added for ON ERROR and ON EMPTY expressions, if any.
+	 *
+	 * Reset for each evaluation of EEOP_JSONEXPR_PATH.
+	 */
+
+	/* Set to true if jsonpath evaluation cause an error.  */
+	NullableDatum error;
+
+	/* Set to true if the jsonpath evaluation returned 0 items. */
+	NullableDatum empty;
+
+	/*
+	 * Addresses of steps that implement the non-ERROR variant of ON EMPTY and
+	 * ON ERROR behaviors, respectively.
+	 */
+	int			jump_empty;
+	int			jump_error;
+
+	/*
+	 * Address of the step to coerce the result value of jsonpath evaluation
+	 * to the RETURNING type using JsonExpr.coercion_expr.  -1 if no coercion
+	 * is necessary or if either JsonExpr.use_io_coercion or
+	 * JsonExpr.use_json_coercion is true.
+	 */
+	int			jump_eval_coercion;
+
+	/*
+	 * Address to jump to when skipping all the steps after performing
+	 * ExecEvalJsonExprPath() so as to return whatever the JsonPath* function
+	 * returned as is, that is, in the cases where there's no error and no
+	 * coercion is necessary.
+	 */
+	int			jump_end;
+
+	/*
+	 * RETURNING type input function invocation info when
+	 * JsonExpr.use_io_coercion is true.
+	 */
+	FmgrInfo   *input_finfo;
+	FunctionCallInfo input_fcinfo;
+
+	/*
+	 * For error-safe evaluation of coercions.  When the ON ERROR behavior is
+	 * not ERROR, a pointer to this is passed to ExecInitExprRec() when
+	 * initializing the coercion expressions or to ExecInitJsonCoercion().
+	 *
+	 * Reset for each evaluation of EEOP_JSONEXPR_PATH.
+	 */
+	ErrorSaveContext escontext;
+} JsonExprState;
+
 
 /* ----------------------------------------------------------------
  *				 Executor State Trees
diff --git a/src/include/nodes/makefuncs.h b/src/include/nodes/makefuncs.h
index 2dc79648d2b..fdc78270e5b 100644
--- a/src/include/nodes/makefuncs.h
+++ b/src/include/nodes/makefuncs.h
@@ -116,5 +116,7 @@ extern Node *makeJsonKeyValue(Node *key, Node *value);
 extern Node *makeJsonIsPredicate(Node *expr, JsonFormat *format,
 								 JsonValueType item_type, bool unique_keys,
 								 int location);
+extern JsonBehavior *makeJsonBehavior(JsonBehaviorType btype, Node *expr,
+									  int location);
 
 #endif							/* MAKEFUNC_H */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 1e2e898851f..9b709f03908 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1716,6 +1716,48 @@ typedef struct JsonOutput
 } JsonOutput;
 
 /*
+ * JsonArgument -
+ *		representation of argument from JSON PASSING clause
+ */
+typedef struct JsonArgument
+{
+	NodeTag		type;
+	JsonValueExpr *val;			/* argument value expression */
+	char	   *name;			/* argument name */
+} JsonArgument;
+
+/*
+ * JsonQuotes -
+ *		representation of [KEEP|OMIT] QUOTES clause for JSON_QUERY()
+ */
+typedef enum JsonQuotes
+{
+	JS_QUOTES_UNSPEC,			/* unspecified */
+	JS_QUOTES_KEEP,				/* KEEP QUOTES */
+	JS_QUOTES_OMIT,				/* OMIT QUOTES */
+} JsonQuotes;
+
+/*
+ * JsonFuncExpr -
+ *		untransformed representation of function expressions for
+ *		SQL/JSON query functions
+ */
+typedef struct JsonFuncExpr
+{
+	NodeTag		type;
+	JsonExprOp	op;				/* expression type */
+	JsonValueExpr *context_item;	/* context item expression */
+	Node	   *pathspec;		/* JSON path specification expression */
+	List	   *passing;		/* list of PASSING clause arguments, if any */
+	JsonOutput *output;			/* output clause, if specified */
+	JsonBehavior *on_empty;		/* ON EMPTY behavior */
+	JsonBehavior *on_error;		/* ON ERROR behavior */
+	JsonWrapper wrapper;		/* array wrapper behavior (JSON_QUERY only) */
+	JsonQuotes	quotes;			/* omit or keep quotes? (JSON_QUERY only) */
+	int			location;		/* token location, or -1 if unknown */
+} JsonFuncExpr;
+
+/*
  * JsonKeyValue -
  *		untransformed representation of JSON object key-value pair for
  *		JSON_OBJECT() and JSON_OBJECTAGG()
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index e57d69f72e2..376f67e6a5f 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -1691,6 +1691,128 @@ typedef struct JsonIsPredicate
 	ParseLoc	location;		/* token location, or -1 if unknown */
 } JsonIsPredicate;
 
+/* Nodes used in SQL/JSON query functions */
+
+/*
+ * JsonWrapper -
+ *		representation of WRAPPER clause for JSON_QUERY()
+ */
+typedef enum JsonWrapper
+{
+	JSW_UNSPEC,
+	JSW_NONE,
+	JSW_CONDITIONAL,
+	JSW_UNCONDITIONAL,
+} JsonWrapper;
+
+/*
+ * JsonBehaviorType -
+ *		enumeration of behavior types used in SQL/JSON ON ERROR/EMPTY clauses
+ *
+ * 		If enum members are reordered, get_json_behavior() from ruleutils.c
+ * 		must be updated accordingly.
+ */
+typedef enum JsonBehaviorType
+{
+	JSON_BEHAVIOR_NULL = 0,
+	JSON_BEHAVIOR_ERROR,
+	JSON_BEHAVIOR_EMPTY,
+	JSON_BEHAVIOR_TRUE,
+	JSON_BEHAVIOR_FALSE,
+	JSON_BEHAVIOR_UNKNOWN,
+	JSON_BEHAVIOR_EMPTY_ARRAY,
+	JSON_BEHAVIOR_EMPTY_OBJECT,
+	JSON_BEHAVIOR_DEFAULT,
+} JsonBehaviorType;
+
+/*
+ * JsonBehavior
+ *		Specifications for ON ERROR / ON EMPTY behaviors of SQL/JSON
+ *		query functions specified by a JsonExpr
+ *
+ * 'expr' is the expression to emit when a given behavior (EMPTY or ERROR)
+ * occurs on evaluating the SQL/JSON query function.  'coerce' is set to true
+ * if 'expr' isn't already of the expected target type given by
+ * JsonExpr.returning.
+ */
+typedef struct JsonBehavior
+{
+	NodeTag		type;
+
+	JsonBehaviorType btype;
+	Node	   *expr;
+	bool		coerce;
+	int			location;		/* token location, or -1 if unknown */
+} JsonBehavior;
+
+/*
+ * JsonExprOp -
+ *		enumeration of SQL/JSON query function types
+ */
+typedef enum JsonExprOp
+{
+	JSON_EXISTS_OP,				/* JSON_EXISTS() */
+	JSON_QUERY_OP,				/* JSON_QUERY() */
+	JSON_VALUE_OP,				/* JSON_VALUE() */
+} JsonExprOp;
+
+/*
+ * JsonExpr -
+ *		Transformed representation of JSON_VALUE(), JSON_QUERY(), and
+ *		JSON_EXISTS()
+ */
+typedef struct JsonExpr
+{
+	Expr		xpr;
+
+	JsonExprOp	op;
+
+	/* jsonb-valued expression to query */
+	Node	   *formatted_expr;
+
+	/* Format of the above expression needed by ruleutils.c */
+	JsonFormat *format;
+
+	/* jsopath-valued expression containing the query pattern */
+	Node	   *path_spec;
+
+	/* Expected type/format of the output. */
+	JsonReturning *returning;
+
+	/* Information about the PASSING argument expressions */
+	List	   *passing_names;
+	List	   *passing_values;
+
+	/* User-specified or default ON EMPTY and ON ERROR behaviors */
+	JsonBehavior *on_empty;
+	JsonBehavior *on_error;
+
+	/*
+	 * Information about converting the result of jsonpath functions
+	 * JsonPathQuery() and JsonPathValue() to the RETURNING type.
+	 *
+	 * coercion_expr is a cast expression if the parser can find it for the
+	 * source and the target type.  If not, either use_io_coercion or
+	 * use_json_coercion is set to determine the coercion method to use at
+	 * runtime; see coerceJsonExprOutput() and ExecInitJsonExpr().
+	 */
+	Node	   *coercion_expr;
+	bool		use_io_coercion;
+	bool		use_json_coercion;
+
+	/* WRAPPER specification for JSON_QUERY */
+	JsonWrapper wrapper;
+
+	/* KEEP or OMIT QUOTES for singleton scalars returned by JSON_QUERY() */
+	bool		omit_quotes;
+
+	/* JsonExpr's collation, if coercion_expr is NULL. */
+	Oid			collation;
+
+	/* Original JsonFuncExpr's location */
+	int			location;
+} JsonExpr;
+
 /* ----------------
  * NullTest
  *