+;;; Prepared statements
+
+(defvar *next-prepared-id-num* 0)
+(defun next-prepared-id ()
+ (let ((num (incf *next-prepared-id-num*)))
+ (format nil "CLSQL_PS_~D" num)))
+
+(defclass postgresql-stmt ()
+ ((database :initarg :database :reader database)
+ (id :initarg :id :reader id)
+ (bindings :initarg :bindings :reader bindings)
+ (field-names :initarg :field-names :accessor stmt-field-names)
+ (result-types :initarg :result-types :reader result-types)))
+
+(defun clsql-type->postgresql-type (type)
+ (cond
+ ((in type :int :integer) "INT4")
+ ((in type :short) "INT2")
+ ((in type :bigint) "INT8")
+ ((in type :float :double :number) "NUMERIC")
+ ((and (consp type) (in (car type) :char :varchar)) "VARCHAR")
+ (t
+ (error 'sql-user-error
+ :message
+ (format nil "Unknown clsql type ~A." type)))))
+
+(defun prepared-sql-to-postgresql-sql (sql)
+ ;; FIXME: Convert #\? to "$n". Don't convert within strings
+ (declare (simple-string sql))
+ (with-output-to-string (out)
+ (do ((len (length sql))
+ (param 0)
+ (in-str nil)
+ (pos 0 (1+ pos)))
+ ((= len pos))
+ (declare (fixnum len param pos))
+ (let ((c (schar sql pos)))
+ (declare (character c))
+ (cond
+ ((or (char= c #\") (char= c #\'))
+ (setq in-str (not in-str))
+ (write-char c out))
+ ((and (char= c #\?) (not in-str))
+ (write-char #\$ out)
+ (write-string (write-to-string (incf param)) out))
+ (t
+ (write-char c out)))))))
+
+(defmethod database-prepare (sql-stmt types (database generic-postgresql-database) result-types field-names)
+ (let ((id (next-prepared-id)))
+ (database-execute-command
+ (format nil "PREPARE ~A (~{~A~^,~}) AS ~A"
+ id
+ (mapcar #'clsql-type->postgresql-type types)
+ (prepared-sql-to-postgresql-sql sql-stmt))
+ database)
+ (make-instance 'postgresql-stmt
+ :id id
+ :database database
+ :result-types result-types
+ :field-names field-names
+ :bindings (make-list (length types)))))
+
+(defmethod database-bind-parameter ((stmt postgresql-stmt) position value)
+ (setf (nth (1- position) (bindings stmt)) value))
+
+(defun binding-to-param (binding)
+ (typecase binding
+ (string
+ (concatenate 'string "'" (sql-escape-quotes binding) "'"))
+ (t
+ binding)))
+
+(defmethod database-run-prepared ((stmt postgresql-stmt))
+ (with-slots (database id bindings field-names result-types) stmt
+ (let ((query (format nil "EXECUTE ~A (~{~A~^,~})"
+ id (mapcar #'binding-to-param bindings))))
+ (cond
+ ((and field-names (not (consp field-names)))
+ (multiple-value-bind (res names)
+ (database-query query database result-types field-names)
+ (setf field-names names)
+ (values res names)))
+ (field-names
+ (values (nth-value 0 (database-query query database result-types nil))
+ field-names))
+ (t
+ (database-query query database result-types field-names))))))
+
+;;; Capabilities