Make the underlying buffer of the ArrayBuffer accessible. (#2836)

JerryScript-DCO-1.0-Signed-off-by: László Langó llango.u-szeged@partner.samsung.com

docs/02.API-REFERENCE.md

@@ -6426,16 +6426,13 @@ jerry_arraybuffer_write (const jerry_value_t value,
 **Summary**
 
 The function allows access to the contents of the Array Buffer directly.
-Only allowed for Array Buffers which were created with
-[jerry_create_arraybuffer_external](#jerry_create_arraybuffer_external)
-function calls. In any other case this function will return `NULL`.
-
-After using the pointer the [jerry_release_value](#jerry_release_value)
-function must be called.
 
 **WARNING!** This operation is for expert use only! The programmer must
 ensure that the returned memory area is used correctly. That is
-there is no out of bounds reads or writes.
+there is no out of bounds reads or writes. The lifetime of the underlying
+data buffer is managed by the ArrayBuffer value. Make sure to acquire the
+value with [`jerry_acquire_value`](#jerry_acquire_value) if the data
+buffer is needed later.
 
 **Prototype**
 
@@ -6447,26 +6444,22 @@ jerry_get_arraybuffer_pointer (const jerry_value_t value);
 - `value` - Array Buffer object.
 - return value
   - pointer to the Array Buffer's data area.
-  - NULL if the `value` is not an Array Buffer object with external memory.
+  - NULL if the `value` is not an Array Buffer object.
 
 **Example**
 
 ```c
 {
-  jerry_value_t buffer;
+  // create the ArrayBuffer
-
+  jerry_value_t buffer = jerry_create_arraybuffer (16);
-  // acquire buffer somewhere which was created by a jerry_create_array_buffer_external call.
 
   uint8_t *const data = jerry_get_arraybuffer_pointer (buffer);
 
-  for (int i = 0; i < 22; i++)
+  for (int i = 0; i < 16; i++)
   {
     data[i] = (uint8_t) (i + 4);
   }
 
-  // required after jerry_get_arraybuffer_pointer call.
-  jerry_release_value (buffer);
-
   // use the Array Buffer
 
   // release buffer as it is not needed after this point

jerry-core/api/jerry.c

@@ -3198,34 +3198,29 @@ jerry_get_arraybuffer_byte_length (const jerry_value_t value) /**< ArrayBuffer *
  * Get a pointer for the start of the ArrayBuffer.
  *
  * Note:
- *    * Only valid for ArrayBuffers created with jerry_create_arraybuffer_external.
  *    * This is a high-risk operation as the bounds are not checked
  *      when accessing the pointer elements.
- *    * jerry_release_value must be called on the ArrayBuffer when the pointer is no longer needed.
  *
  * @return pointer to the back-buffer of the ArrayBuffer.
- *         pointer is NULL if the parameter is not an ArrayBuffer with external memory
+ *         pointer is NULL if the parameter is not an ArrayBuffer
-             or it is not an ArrayBuffer at all.
  */
 uint8_t *
-jerry_get_arraybuffer_pointer (const jerry_value_t value) /**< Array Buffer to use */
+jerry_get_arraybuffer_pointer (const jerry_value_t array_buffer) /**< Array Buffer to use */
 {
   jerry_assert_api_available ();
+
 #if ENABLED (JERRY_ES2015_BUILTIN_TYPEDARRAY)
-  if (!ecma_is_arraybuffer (value))
+  if (ecma_is_value_error_reference (array_buffer)
+      || !ecma_is_arraybuffer (array_buffer))
   {
     return NULL;
   }
 
-  ecma_object_t *buffer_p = ecma_get_object_from_value (value);
+  ecma_object_t *buffer_p = ecma_get_object_from_value (array_buffer);
-  if (ECMA_ARRAYBUFFER_HAS_EXTERNAL_MEMORY (buffer_p))
+  lit_utf8_byte_t *mem_buffer_p = ecma_arraybuffer_get_buffer (buffer_p);
-  {
+  return (uint8_t *const) mem_buffer_p;
-    jerry_acquire_value (value);
-    lit_utf8_byte_t *mem_buffer_p = ecma_arraybuffer_get_buffer (buffer_p);
-    return (uint8_t *const) mem_buffer_p;
-  }
 #else /* !ENABLED (JERRY_ES2015_BUILTIN_TYPEDARRAY) */
-  JERRY_UNUSED (value);
+  JERRY_UNUSED (array_buffer);
 #endif /* ENABLED (JERRY_ES2015_BUILTIN_TYPEDARRAY) */
 
   return NULL;

tests/unit-core/test-arraybuffer.c

@@ -326,8 +326,6 @@ main (void)
       sum += data[i];
     }
 
-    jerry_release_value (buffer);
-
     const jerry_char_t eval_test_arraybuffer[] = TEST_STRING_LITERAL (
       "var sum = 0;"
       "for (var i = 0; i < array.length; i++)"