Allow to create ArrayBuffer with empty external user data (#3373)

JerryScript-DCO-1.0-Signed-off-by: Roland Takacs r.takacs2@partner.samsung.com

docs/02.API-REFERENCE.md

@@ -3707,7 +3707,7 @@ jerry_create_arraybuffer_external (const jerry_length_t size
 - `free_cb` - the callback function called when the object is released
 - return value
   - the new ArrayBuffer as a `jerry_value_t`
-  - if the `size` is zero or `buffer_p` is a null pointer will return RangeError
+  - if the `size` is zero or `buffer_p` is a null pointer this will return an empty ArrayBuffer.
 
 *New in version 2.0*.
 

jerry-core/api/jerry.c

@@ -3446,7 +3446,7 @@ jerry_create_arraybuffer (const jerry_length_t size) /**< size of the ArrayBuffe
  *     * the size is specified in bytes.
  *     * the buffer passed should be at least the specified bytes big.
  *     * if the typed arrays are disabled this will return a TypeError.
- *     * if the size is zero or the buffer_p is a null pointer this will return a RangeError.
+ *     * if the size is zero or buffer_p is a null pointer this will return an empty ArrayBuffer.
  *
  * @return value of the construced ArrayBuffer object
  */
@@ -3458,14 +3458,19 @@ jerry_create_arraybuffer_external (const jerry_length_t size, /**< size of the b
   jerry_assert_api_available ();
 
 #if ENABLED (JERRY_ES2015_BUILTIN_TYPEDARRAY)
-  if (size == 0 || buffer_p == NULL)
-  {
-    return jerry_throw (ecma_raise_range_error (ECMA_ERR_MSG ("invalid buffer size or storage reference")));
-  }
+  ecma_object_t *arraybuffer;
 
-  ecma_object_t *arraybuffer = ecma_arraybuffer_new_object_external (size,
+  if (JERRY_UNLIKELY (size == 0 || buffer_p == NULL))
+  {
+    arraybuffer = ecma_arraybuffer_new_object_external (0, NULL, (ecma_object_native_free_callback_t) free_cb);
+  }
+  else
+  {
+    arraybuffer = ecma_arraybuffer_new_object_external (size,
                                                         buffer_p,
                                                         (ecma_object_native_free_callback_t) free_cb);
+  }
+
   return jerry_return (ecma_make_object_value (arraybuffer));
 #else /* !ENABLED (JERRY_ES2015_BUILTIN_TYPEDARRAY) */
   JERRY_UNUSED (size);

tests/unit-core/test-arraybuffer.c

@@ -250,6 +250,23 @@ main (void)
     jerry_release_value (arraybuffer);
   }
 
+  /* Test zero length external ArrayBuffer */
+  {
+    const uint32_t length = 0;
+    jerry_value_t arraybuffer = jerry_create_arraybuffer_external (length, NULL, NULL);
+    TEST_ASSERT (!jerry_value_is_error (arraybuffer));
+    TEST_ASSERT (jerry_value_is_arraybuffer (arraybuffer));
+    TEST_ASSERT (jerry_get_arraybuffer_byte_length (arraybuffer) == length);
+
+    uint8_t data[20];
+    memset (data, 11, 20);
+
+    jerry_length_t bytes_written = jerry_arraybuffer_write (arraybuffer, 0, data, 20);
+    TEST_ASSERT (bytes_written == 0);
+
+    jerry_release_value (arraybuffer);
+  }
+
   /* Test ArrayBuffer with buffer allocated externally */
   {
     const uint32_t buffer_size = 15;
@@ -346,14 +363,6 @@ main (void)
     jerry_release_value (buffer);
   }
 
-  /* Test ArrayBuffer external with invalid arguments */
-  {
-    jerry_value_t input_buffer = jerry_create_arraybuffer_external (0, NULL, NULL);
-    TEST_ASSERT (jerry_value_is_error (input_buffer));
-    TEST_ASSERT (jerry_get_error_type (input_buffer) == JERRY_ERROR_RANGE);
-    jerry_release_value (input_buffer);
-  }
-
   /* Test ArrayBuffer detach */
   {
     const uint32_t length = 1;