Use newer API for fetching data chunks

duckdb-api.lisp

@@ -331,28 +331,21 @@
   (result p-duckdb-result)
   (col idx))
 
-(defcfun duckdb-result-chunk-count idx
+(defcfun duckdb-fetch-chunk (duckdb-data-chunk)
   (result (:struct duckdb-result)))
 
-(defun result-chunk-count (p-result)
-  (duckdb-result-chunk-count (mem-ref p-result '(:struct duckdb-result))))
-
-(defcfun duckdb-result-get-chunk (duckdb-data-chunk)
-  (result (:struct duckdb-result))
-  (chunk-index idx))
-
 (defcfun duckdb-destroy-data-chunk :void
   (chunk (:pointer duckdb-data-chunk)))
 
-(defmacro with-data-chunk ((chunk-var result chunk-index) &body body)
-  `(let ((,chunk-var (duckdb-result-get-chunk
-                      (mem-ref ,result '(:struct duckdb-result))
-                      ,chunk-index)))
-     (unwind-protect
-          (progn ,@body)
-       (with-foreign-object (p-chunk '(:pointer duckdb-data-chunk))
-         (setf (mem-ref p-chunk 'duckdb-data-chunk) ,chunk-var)
-         (duckdb-destroy-data-chunk p-chunk)))))
+(defmacro with-data-chunk ((chunk-var result) &body body)
+  `(let ((,chunk-var (duckdb-fetch-chunk
+                      (mem-ref ,result '(:struct duckdb-result)))))
+     (if (null-pointer-p ,chunk-var)
+         (let ((,chunk-var nil)) (progn ,@body))
+         (unwind-protect (progn ,@body)
+           (with-foreign-object (p-chunk '(:pointer duckdb-data-chunk))
+             (setf (mem-ref p-chunk 'duckdb-data-chunk) ,chunk-var)
+             (duckdb-destroy-data-chunk p-chunk))))))
 
 (defun result-get-chunk (p-result i)
   (duckdb-result-get-chunk (mem-ref p-result '(:struct duckdb-result)) i))

duckdb.lisp

@@ -425,22 +425,22 @@ cleanup."
 
 (defun translate-result (result &optional sql-null-return-value)
   (let* ((p-result (handle result))
-         (chunk-count (duckdb-api:result-chunk-count p-result))
          (column-count (duckdb-api:duckdb-column-count p-result))
          (result-alist
            (loop :for column-index :below column-count
                  :collect (cons (duckdb-api:duckdb-column-name p-result column-index)
                                 (make-array '(0) :adjustable t :fill-pointer 0))))
          column-types
          (row-count
-           (loop :for chunk-index :below chunk-count
-                 :sum (duckdb-api:with-data-chunk (chunk p-result chunk-index)
-                        (multiple-value-bind (types chunk-size)
-                            (translate-chunk result-alist
-                                             chunk
-                                             sql-null-return-value)
-                          (setf column-types types)
-                          chunk-size)))))
+           (loop :for n := (duckdb-api:with-data-chunk (chunk p-result)
+                             (when chunk
+                               (multiple-value-bind (types chunk-size)
+                                   (translate-chunk result-alist
+                                                    chunk
+                                                    sql-null-return-value)
+                                 (setf column-types types)
+                                 chunk-size)))
+                 :while n :sum n)))
     (values result-alist column-types row-count)))
 
 (defun assert-parameter-count (statement values)