Add a simple Job queue in default port. (#1685)

Job queue (event loop) is the basis of Promise. Each port should implement their own job queue.

JerryScript-DCO-1.0-Signed-off-by: Zidong Jiang zidong.jiang@intel.com

targets/default/jerry-port-default-jobqueue.c

@@ -0,0 +1,141 @@
+/* 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 "jerry-port.h"
+#include "jerry-port-default.h"
+#include "jmem.h"
+#include "jrt.h"
+
+#ifndef CONFIG_DISABLE_ES2015_PROMISE_BUILTIN
+
+typedef struct jerry_port_queueitem_t jerry_port_queueitem_t;
+
+/**
+ * Description of the queue item.
+ */
+struct jerry_port_queueitem_t
+{
+  jerry_port_queueitem_t *next_p; /**< points to next item */
+  jerry_job_handler_t handler; /**< the handler for the job*/
+  void *job_p; /**< points to the job */
+};
+
+/**
+ * Description of a job queue (FIFO)
+ */
+typedef struct
+{
+  jerry_port_queueitem_t *head_p; /**< points to the head item of the queue */
+  jerry_port_queueitem_t *tail_p; /**< points to the tail item of the queue*/
+} jerry_port_jobqueue_t;
+
+static jerry_port_jobqueue_t queue;
+
+/**
+ * Initialize the job queue
+ */
+void jerry_port_jobqueue_init (void)
+{
+  queue.head_p = NULL;
+  queue.tail_p = NULL;
+} /* jerry_port_jobqueue_init */
+
+/**
+ * Enqueue a job
+ */
+void jerry_port_jobqueue_enqueue (jerry_job_handler_t handler, /**< the handler for the job */
+                                  void *job_p) /**< the job */
+{
+  jerry_port_queueitem_t *item_p = jmem_heap_alloc_block (sizeof (jerry_port_queueitem_t));
+  item_p->job_p = job_p;
+  item_p->handler = handler;
+
+  if (queue.head_p == NULL)
+  {
+    JERRY_ASSERT (queue.tail_p == NULL);
+
+    queue.head_p = item_p;
+    item_p->next_p = NULL;
+    queue.tail_p = item_p;
+
+    return;
+  }
+
+  JERRY_ASSERT (queue.tail_p != NULL);
+
+  queue.tail_p->next_p = item_p;
+  queue.tail_p = item_p;
+} /* jerry_port_jobqueue_enqueue */
+
+/**
+ * Dequeue and get the job.
+ * @return pointer to jerry_port_queueitem_t
+ *         It should be freed with jmem_heap_free_block
+ */
+static jerry_port_queueitem_t *
+jerry_port_jobqueue_dequeue (void)
+{
+  if (queue.head_p == NULL)
+  {
+    JERRY_ASSERT (queue.tail_p == NULL);
+
+    return NULL;
+  }
+
+  JERRY_ASSERT (queue.tail_p != NULL);
+
+  jerry_port_queueitem_t *item_p = queue.head_p;
+  queue.head_p = queue.head_p->next_p;
+
+  return item_p;
+} /* jerry_port_jobqueue_dequeue */
+
+/**
+ * Start the jobqueue.
+ * @return jerry value
+ *         If exception happens in the handler, stop the queue
+ *         and return the exception.
+ *         Otherwise, return undefined
+ */
+jerry_value_t
+jerry_port_jobqueue_run (void)
+{
+  jerry_value_t ret;
+
+  while (true)
+  {
+    jerry_port_queueitem_t *item_p = jerry_port_jobqueue_dequeue ();
+
+    if (item_p == NULL)
+    {
+      return jerry_create_undefined ();
+    }
+
+    void *job_p = item_p->job_p;
+    jerry_job_handler_t handler = item_p->handler;
+    jmem_heap_free_block (item_p, sizeof (jerry_port_queueitem_t));
+    ret = handler (job_p);
+
+    if (jerry_value_has_error_flag (ret))
+    {
+      return ret;
+    }
+
+    jerry_release_value (ret);
+  }
+} /* jerry_port_jobqueue_run */
+
+#endif /* !CONFIG_DISABLE_ES2015_PROMISE_BUILTIN */

targets/default/jerry-port-default.h

@@ -16,6 +16,7 @@
 #ifndef JERRY_PORT_DEFAULT_H
 #define JERRY_PORT_DEFAULT_H
 
+#include "jerryscript.h"
 #include "jerry-port.h"
 
 #include <stdbool.h>
@@ -36,6 +37,11 @@ bool jerry_port_default_is_abort_on_fail (void);
 jerry_log_level_t jerry_port_default_get_log_level (void);
 void jerry_port_default_set_log_level (jerry_log_level_t level);
 
+#ifndef CONFIG_DISABLE_ES2015_PROMISE_BUILTIN
+void jerry_port_jobqueue_init (void);
+jerry_value_t jerry_port_jobqueue_run (void);
+#endif /* !CONFIG_DISABLE_ES2015_PROMISE_BUILTIN */
+
 /**
  * @}
  */