Introduce new Promise API methods

The new API methods make it possible to get a Promise object's
result and it's state.

JerryScript-DCO-1.0-Signed-off-by: Peter Gal pgal.u-szeged@partner.samsung.com

Author: galpeter

jerry-core/api/jerry.c

@@ -71,6 +71,14 @@ JERRY_STATIC_ASSERT ((int) RE_FLAG_GLOBAL == (int) JERRY_REGEXP_FLAG_GLOBAL
                      re_flags_t_must_be_equal_to_jerry_regexp_flags_t);
 #endif /* ENABLED (JERRY_BUILTIN_REGEXP) */
 
+#if ENABLED (JERRY_ES2015_BUILTIN_PROMISE)
+/* The internal ECMA_PROMISE_STATE_* values are "one byte away" from the API values */
+JERRY_STATIC_ASSERT (((ECMA_PROMISE_STATE_PENDING + 1) == JERRY_PROMISE_STATE_PENDING)
+                     && ((ECMA_PROMISE_STATE_FULFILLED + 1) == JERRY_PROMISE_STATE_FULFILLED)
+                     && ((ECMA_PROMISE_STATE_REJECTED + 1) == JERRY_PROMISE_STATE_REJECTED),
+                     promise_internal_state_matches_external);
+#endif /* ENABLED (JERRY_ES2015_BUILTIN_PROMISE) */
+
 #if !ENABLED (JERRY_PARSER) && !ENABLED (JERRY_SNAPSHOT_EXEC)
 #error "JERRY_SNAPSHOT_EXEC must be enabled if JERRY_PARSER is disabled!"
 #endif /* !ENABLED (JERRY_PARSER) && !ENABLED (JERRY_SNAPSHOT_EXEC) */
@@ -2845,6 +2853,57 @@ jerry_resolve_or_reject_promise (jerry_value_t promise, /**< the promise value *
 #endif /* ENABLED (JERRY_ES2015_BUILTIN_PROMISE) */
 } /* jerry_resolve_or_reject_promise */
 
+/**
+ * Get the result of a promise.
+ *
+ * @return - Promise result
+ *         - Type error if the promise support was not enabled or the input was not a promise object
+ */
+jerry_value_t
+jerry_get_promise_result (const jerry_value_t promise) /**< promise object to get the result from */
+{
+#if ENABLED (JERRY_ES2015_BUILTIN_PROMISE)
+  if (!jerry_value_is_promise (promise))
+  {
+    return jerry_throw (ecma_raise_type_error (ECMA_ERR_MSG (wrong_args_msg_p)));
+  }
+
+  ecma_value_t result = ecma_promise_get_result (ecma_get_object_from_value (promise));
+  return result;
+#else /* !ENABLED (JERRY_ES2015_BUILTIN_PROMISE) */
+  JERRY_UNUSED (promise);
+  return jerry_throw (ecma_raise_type_error (ECMA_ERR_MSG ("Promise not supported.")));
+#endif /* ENABLED (JERRY_ES2015_BUILTIN_PROMISE) */
+} /* jerry_get_promise_result */
+
+/**
+ * Get the state of a promise object.
+ *
+ * @return - the state of the promise (one of the jerry_promise_state_t enum values)
+ *         - JERRY_PROMISE_STATE_NONE is only returned if the input is not a promise object
+ *           or the promise support was not enabled.
+ */
+jerry_promise_state_t
+jerry_get_promise_state (const jerry_value_t promise) /**< promise object to get the state from */
+{
+#if ENABLED (JERRY_ES2015_BUILTIN_PROMISE)
+  if (!jerry_value_is_promise (promise))
+  {
+    return JERRY_PROMISE_STATE_NONE;
+  }
+
+  uint8_t state = ecma_promise_get_state (ecma_get_object_from_value (promise));
+
+  JERRY_ASSERT (state < ECMA_PROMISE_STATE__COUNT);
+
+  /* Static assert above guarantees the mapping from internal type to external type. */
+  return (jerry_promise_state_t) (state + 1);
+#else /* !ENABLED (JERRY_ES2015_BUILTIN_PROMISE) */
+  JERRY_UNUSED (promise);
+  return JERRY_PROMISE_STATE_NONE;
+#endif /* ENABLED (JERRY_ES2015_BUILTIN_PROMISE) */
+} /* jerry_get_promise_state */
+
 /**
  * Call the SymbolDescriptiveString ecma builtin operation on the symbol value.
  *

jerry-core/ecma/operations/ecma-promise-object.c

@@ -53,7 +53,7 @@ ecma_is_promise (ecma_object_t *obj_p) /**< points to object */
  * @return ecma value of the promise result.
  *         Returned value must be freed with ecma_free_value
  */
-static inline ecma_value_t
+ecma_value_t
 ecma_promise_get_result (ecma_object_t *obj_p) /**< points to promise object */
 {
   JERRY_ASSERT (ecma_is_promise (obj_p));
@@ -84,7 +84,7 @@ ecma_promise_set_result (ecma_object_t *obj_p, /**< points to promise object */
  *
  * @return the state's enum value
  */
-static inline uint8_t JERRY_ATTR_ALWAYS_INLINE
+uint8_t JERRY_ATTR_ALWAYS_INLINE
 ecma_promise_get_state (ecma_object_t *obj_p) /**< points to promise object */
 {
   JERRY_ASSERT (ecma_is_promise (obj_p));

jerry-core/ecma/operations/ecma-promise-object.h

@@ -71,6 +71,8 @@ typedef struct
 bool ecma_is_promise (ecma_object_t *obj_p);
 ecma_value_t
 ecma_op_create_promise_object (ecma_value_t executor, ecma_promise_executor_type_t type);
+uint8_t ecma_promise_get_state (ecma_object_t *promise_p);
+ecma_value_t ecma_promise_get_result (ecma_object_t *promise_p);
 ecma_value_t ecma_promise_new_capability (void);
 ecma_value_t
 ecma_promise_then (ecma_value_t promise,

jerry-core/include/jerryscript-core.h

@@ -545,10 +545,21 @@ bool jerry_foreach_object_property (const jerry_value_t obj_val, jerry_object_pr
                                     void *user_data_p);
 
 /**
- * Promise resolve/reject functions.
+ * Promise functions.
  */
 jerry_value_t jerry_resolve_or_reject_promise (jerry_value_t promise, jerry_value_t argument, bool is_resolve);
 
+typedef enum
+{
+  JERRY_PROMISE_STATE_NONE = 0u,
+  JERRY_PROMISE_STATE_PENDING,
+  JERRY_PROMISE_STATE_FULFILLED,
+  JERRY_PROMISE_STATE_REJECTED,
+} jerry_promise_state_t;
+
+jerry_value_t jerry_get_promise_result (const jerry_value_t promise);
+jerry_promise_state_t jerry_get_promise_state (const jerry_value_t promise);
+
 /**
  * Symbol functions.
  */

tests/unit-core/test-api-promise.c

@@ -0,0 +1,178 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "jerryscript.h"
+#include "jerryscript-port.h"
+#include "jerryscript-port-default.h"
+#include "test-common.h"
+
+static void
+test_promise_resolve_success (void)
+{
+  jerry_value_t my_promise = jerry_create_promise ();
+
+  // A created promise has an undefined promise result by default and a pending state
+  {
+    jerry_value_t promise_result = jerry_get_promise_result (my_promise);
+    TEST_ASSERT (jerry_value_is_undefined (promise_result));
+
+    jerry_promise_state_t promise_state = jerry_get_promise_state (my_promise);
+    TEST_ASSERT (promise_state == JERRY_PROMISE_STATE_PENDING);
+
+    jerry_release_value (promise_result);
+  }
+
+  // A resolved promise should have the result of from the resolve call and a fulfilled state
+  {
+    jerry_value_t resolve_result = jerry_resolve_or_reject_promise (my_promise, jerry_create_number (3), true);
+
+    jerry_value_t promise_result = jerry_get_promise_result (my_promise);
+    TEST_ASSERT (jerry_value_is_number (promise_result));
+    TEST_ASSERT (jerry_get_number_value (promise_result) == 3.0);
+
+    jerry_promise_state_t promise_state = jerry_get_promise_state (my_promise);
+    TEST_ASSERT (promise_state == JERRY_PROMISE_STATE_FULFILLED);
+
+    jerry_release_value (promise_result);
+
+    jerry_release_value (resolve_result);
+  }
+
+  // Resolvind a promise again does not change the result/state
+  {
+    jerry_value_t resolve_result = jerry_resolve_or_reject_promise (my_promise, jerry_create_number (50), false);
+
+    jerry_value_t promise_result = jerry_get_promise_result (my_promise);
+    TEST_ASSERT (jerry_value_is_number (promise_result));
+    TEST_ASSERT (jerry_get_number_value (promise_result) == 3.0);
+
+    jerry_promise_state_t promise_state = jerry_get_promise_state (my_promise);
+    TEST_ASSERT (promise_state == JERRY_PROMISE_STATE_FULFILLED);
+
+    jerry_release_value (promise_result);
+
+    jerry_release_value (resolve_result);
+  }
+
+  jerry_release_value (my_promise);
+} /* test_promise_resolve_success */
+
+static void
+test_promise_resolve_fail (void)
+{
+  jerry_value_t my_promise = jerry_create_promise ();
+
+  // A created promise has an undefined promise result by default and a pending state
+  {
+    jerry_value_t promise_result = jerry_get_promise_result (my_promise);
+    TEST_ASSERT (jerry_value_is_undefined (promise_result));
+
+    jerry_promise_state_t promise_state = jerry_get_promise_state (my_promise);
+    TEST_ASSERT (promise_state == JERRY_PROMISE_STATE_PENDING);
+
+    jerry_release_value (promise_result);
+  }
+
+  // A resolved promise should have the result of from the resolve call and a fulfilled state
+  {
+    jerry_value_t error_value = jerry_create_error (JERRY_ERROR_TYPE, (const jerry_char_t *) "resolve_fail");
+    jerry_value_t error_obj = jerry_get_value_from_error (error_value, true);
+    jerry_value_t resolve_result = jerry_resolve_or_reject_promise (my_promise, error_obj, false);
+    jerry_release_value (error_obj);
+
+    jerry_value_t promise_result = jerry_get_promise_result (my_promise);
+    // The error is not throw that's why it is only an error object.
+    TEST_ASSERT (jerry_value_is_object (promise_result));
+    TEST_ASSERT (jerry_get_error_type (promise_result) == JERRY_ERROR_TYPE);
+
+    jerry_promise_state_t promise_state = jerry_get_promise_state (my_promise);
+    TEST_ASSERT (promise_state == JERRY_PROMISE_STATE_REJECTED);
+
+    jerry_release_value (promise_result);
+
+    jerry_release_value (resolve_result);
+  }
+
+  // Resolvind a promise again does not change the result/state
+  {
+    jerry_value_t resolve_result = jerry_resolve_or_reject_promise (my_promise, jerry_create_number (50), true);
+
+    jerry_value_t promise_result = jerry_get_promise_result (my_promise);
+    TEST_ASSERT (jerry_value_is_object (promise_result));
+    TEST_ASSERT (jerry_get_error_type (promise_result) == JERRY_ERROR_TYPE);
+
+    jerry_promise_state_t promise_state = jerry_get_promise_state (my_promise);
+    TEST_ASSERT (promise_state == JERRY_PROMISE_STATE_REJECTED);
+
+    jerry_release_value (promise_result);
+
+    jerry_release_value (resolve_result);
+  }
+
+  jerry_release_value (my_promise);
+} /* test_promise_resolve_fail */
+
+static void
+test_promise_from_js (void)
+{
+  const jerry_char_t test_source[] =
+    "(new Promise(function(rs ,rj) { rs(30); })).then(function(v) { return v + 1; })";
+
+  jerry_value_t parsed_code_val = jerry_parse (NULL,
+                                               0,
+                                               test_source,
+                                               sizeof (test_source) - 1,
+                                               JERRY_PARSE_NO_OPTS);
+  TEST_ASSERT (!jerry_value_is_error (parsed_code_val));
+
+  jerry_value_t res = jerry_run (parsed_code_val);
+  TEST_ASSERT (jerry_value_is_promise (res));
+
+  TEST_ASSERT (jerry_get_promise_state (res) == JERRY_PROMISE_STATE_PENDING);
+
+  jerry_value_t run_result = jerry_run_all_enqueued_jobs ();
+  TEST_ASSERT (jerry_value_is_undefined (run_result));
+  jerry_release_value (run_result);
+
+  TEST_ASSERT (jerry_get_promise_state (res) == JERRY_PROMISE_STATE_FULFILLED);
+  jerry_value_t promise_result = jerry_get_promise_result (res);
+  TEST_ASSERT (jerry_value_is_number (promise_result));
+  TEST_ASSERT (jerry_get_number_value (promise_result) == 31.0);
+
+  jerry_release_value (promise_result);
+  jerry_release_value (res);
+  jerry_release_value (parsed_code_val);
+} /* test_promise_from_js */
+
+int
+main (void)
+{
+  if (!jerry_is_feature_enabled (JERRY_FEATURE_PROMISE))
+  {
+    jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Promise is disabled!\n");
+    return 0;
+  }
+
+  jerry_init (JERRY_INIT_EMPTY);
+
+  test_promise_resolve_fail ();
+  test_promise_resolve_success ();
+
+  test_promise_from_js ();
+
+  jerry_cleanup ();
+
+  return 0;
+} /* main */