introduce bind buffer step

python/arrow_odbc/reader.py

@@ -76,7 +76,7 @@ def more_results(
         ptr_schema = _export_schema_to_c(schema)
 
         with ffi.new("bool *") as has_more_results_c:
-            error = lib.arrow_odbc_reader_next_result_set(
+            error = lib.arrow_odbc_reader_bind_buffers(
                 self.handle,
                 has_more_results_c,
                 batch_size,

src/reader.rs

@@ -166,6 +166,40 @@ pub unsafe extern "C" fn arrow_odbc_reader_next_result_set(
     null_mut()
 }
 
+/// # Safety
+///
+/// * `reader` must point to a valid non-null reader, allocated by [`arrow_odbc_reader_make`].
+/// * `has_more_results` must point to a valid boolean.
+/// * `schema`: Optional input arrow schema. NULL means no input schema is supplied. Should a
+///   schema be supplied `schema` Rust will take ownership of it an the `schema` will be
+///   overwritten with an empty one. This means the Python code, must only deallocate the memory
+///   directly pointed to by `schema`, but not freeing the resources of the passed schema.
+#[no_mangle]
+pub unsafe extern "C" fn arrow_odbc_reader_bind_buffers(
+    mut reader: NonNull<ArrowOdbcReader>,
+    has_more_results: *mut bool,
+    max_num_rows_per_batch: usize,
+    max_bytes_per_batch: usize,
+    max_text_size: usize,
+    max_binary_size: usize,
+    fallibale_allocations: bool,
+    schema: *mut c_void,
+) -> *mut ArrowOdbcError {
+    let schema = take_schema(schema);
+
+    let reader_builder = reader_builder_from_c_args(
+        max_text_size,
+        max_binary_size,
+        max_num_rows_per_batch,
+        max_bytes_per_batch,
+        fallibale_allocations,
+        schema,
+    );
+    // Move cursor to the next result set.
+    *has_more_results = try_!(reader.as_mut().next_result_set(reader_builder));
+    null_mut()
+}
+
 /// Retrieve the associated schema from a reader.
 #[no_mangle]
 pub unsafe extern "C" fn arrow_odbc_reader_schema(