Revive target: ESP8266

This patch updates ESP8266 build system and code base as well.
 - Removed unnecessary files.
 - Decreased code size.
 - Refactored jerry_{port, extapi, run}.c to make it more easy to handle.
 - Readme.md is updated as well which contains detailed step by step description about how to set up environment and use JerryScript.

Finally, it solves the related issue #1375.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

targets/esp8266/user/jerry_extapi.c

@@ -0,0 +1,177 @@
+/* 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 <stdlib.h>
+#include <stdio.h>
+
+#include "c_types.h"
+#include "gpio.h"
+
+#include "jerryscript.h"
+#include "jerry_extapi.h"
+
+#define __UNUSED__ __attribute__((unused))
+
+#define DELCARE_HANDLER(NAME) \
+static jerry_value_t \
+NAME ## _handler (const jerry_value_t  function_obj_val __UNUSED__, \
+                  const jerry_value_t  this_val __UNUSED__, \
+                  const jerry_value_t  args_p[], \
+                  const jerry_length_t  args_cnt)
+
+#define REGISTER_HANDLER(NAME) \
+  register_native_function ( # NAME, NAME ## _handler)
+
+DELCARE_HANDLER(assert) {
+  if (args_cnt == 1
+      && jerry_value_is_boolean (args_p[0])
+      && jerry_get_boolean_value (args_p[0]))
+  {
+    printf (">> Jerry assert true\r\n");
+    return jerry_create_boolean (true);
+  }
+  printf ("Script assertion failed\n");
+  exit (JERRY_STANDALONE_EXIT_CODE_FAIL);
+  return jerry_create_boolean (false);
+} /* assert */
+
+
+DELCARE_HANDLER(print) {
+  if (args_cnt)
+  {
+    for (jerry_length_t cc = 0; cc < args_cnt; cc++)
+    {
+      if (jerry_value_is_string (args_p[cc]))
+      {
+        jerry_size_t size = jerry_get_string_size (args_p[0]);
+        char *buffer;
+        buffer = (char *) malloc(size + 1);
+
+        if(!buffer)
+        {
+            // not enough memory for this string.
+            printf("[<too-long-string>]");
+            continue;
+        }
+
+        jerry_string_to_char_buffer (args_p[cc],
+                                     (jerry_char_t *) buffer,
+                                     size);
+        *(buffer + size) = 0;
+        printf("%s ", buffer);
+        free (buffer);
+      }
+      else
+      {
+        printf ("(%d) ", args_p[cc]);
+      }
+    }
+    printf ("\r\n");
+  }
+  return jerry_create_boolean (true);
+} /* print */
+
+DELCARE_HANDLER(gpio_dir) {
+  if (args_cnt < 2)
+  {
+    return jerry_create_boolean (false);
+  }
+
+  int port = (int) jerry_get_number_value (args_p[0]);
+  int value = (int) jerry_get_number_value (args_p[1]);
+
+  if (value)
+  {
+    GPIO_AS_OUTPUT(1 << port);
+  }
+  else
+  {
+    GPIO_AS_INPUT(1 << port);
+  }
+
+  return jerry_create_boolean (true);
+} /* gpio_dir */
+
+DELCARE_HANDLER(gpio_set) {
+  if (args_cnt < 2)
+  {
+    return jerry_create_boolean (false);
+  }
+
+  int port = (int) jerry_get_number_value (args_p[0]);
+  int value = (int) jerry_get_number_value (args_p[1]);
+
+  GPIO_OUTPUT_SET(port, value);
+
+  return jerry_create_boolean (true);
+} /* gpio_set */
+
+
+DELCARE_HANDLER(gpio_get) {
+  if (args_cnt < 1)
+  {
+    return jerry_create_boolean (false);
+  }
+
+  int port = (int) jerry_get_number_value (args_p[0]);
+  int value = GPIO_INPUT_GET(port) ? 1 : 0;
+
+  return jerry_create_number ((double) value);
+} /* gpio_get */
+
+static bool
+register_native_function (const char* name,
+                          jerry_external_handler_t handler)
+{
+  jerry_value_t global_obj_val = jerry_get_global_object ();
+  jerry_value_t reg_func_val = jerry_create_external_function (handler);
+  bool bok = true;
+
+  if (!(jerry_value_is_function (reg_func_val)
+        && jerry_value_is_constructor (reg_func_val)))
+  {
+    printf ("!!! create_external_function failed !!!\r\n");
+    jerry_release_value (reg_func_val);
+    jerry_release_value (global_obj_val);
+    return false;
+  }
+
+  jerry_value_t prop_name_val = jerry_create_string ((const jerry_char_t *) name);
+  jerry_value_t res = jerry_set_property (global_obj_val, prop_name_val, reg_func_val);
+
+  jerry_release_value (reg_func_val);
+  jerry_release_value (global_obj_val);
+  jerry_release_value (prop_name_val);
+
+  if (jerry_value_has_error_flag (res))
+  {
+    printf ("!!! register_native_function failed: [%s]\r\n", name);
+    jerry_release_value (res);
+    return false;
+  }
+
+  jerry_release_value (res);
+
+  return true;
+} /* register_native_function */
+
+void js_register_functions (void)
+{
+  REGISTER_HANDLER(assert);
+  REGISTER_HANDLER(print);
+  REGISTER_HANDLER(gpio_dir);
+  REGISTER_HANDLER(gpio_set);
+  REGISTER_HANDLER(gpio_get);
+} /* js_register_functions */