Rework the public API (#4829)

Related to #4186.

Some notable changes:
  - The term 'Error' now strictly refers to native Error objects defined in
    the ECMA standard, which are ordinary objects. All other uses of
    'error' or 'error reference' where the term refers to a thrown value is
    now called 'exception'.

  - Simplified the naming scheme of many String API functions. These functions
    will now also take an 'encoding' argument to specify the desired
    encoding in which to operate.

  - Removed the substring-copy-to-buffer functions. These functions
    behaved awkwardly, as they use character index to specify the
    start/end positions, and were mostly used incorrectly with byte
    offsets instead. The functionality can still be replicated with
    other functions if necessary.

  - String-to-buffer functions will no longer fail if the buffer is not
    sufficiently large, the string will instead be cropped.

  - Fixed the usage of the '_sz' prefix in many API functions. The term
    'sz' means zero-terminated string in hungarian notation, this was
    used incorrectly in many cases.

  - Renamed most of the public API functions to have shorter, more on-point
    names, rather than the often too long descriptive names. Functions are now
    also grouped by the type of value they operate on, where this makes
    sense.

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu

jerry-ext/handler/handler-assert.c

@@ -38,52 +38,41 @@ jerryx_handler_assert_fatal (const jerry_call_info_t *call_info_p, /**< call inf
 
   if (args_cnt == 1 && jerry_value_is_true (args_p[0]))
   {
-    return jerry_create_boolean (true);
+    return jerry_boolean (true);
   }
 
   /* Assert failed, print a bit of JS backtrace */
   jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Script Error: assertion failed\n");
 
-  if (jerry_is_feature_enabled (JERRY_FEATURE_LINE_INFO))
+  if (jerry_feature_enabled (JERRY_FEATURE_LINE_INFO))
   {
     jerry_port_log (JERRY_LOG_LEVEL_ERROR, "Script backtrace (top 5):\n");
 
     /* If the line info feature is disabled an empty array will be returned. */
-    jerry_value_t backtrace_array = jerry_get_backtrace (5);
-    uint32_t array_length = jerry_get_array_length (backtrace_array);
+    jerry_value_t backtrace_array = jerry_backtrace (5);
+    uint32_t array_length = jerry_array_length (backtrace_array);
 
     for (uint32_t idx = 0; idx < array_length; idx++)
     {
-      jerry_value_t property = jerry_get_property_by_index (backtrace_array, idx);
-
-      jerry_length_t total_size = jerry_get_utf8_string_size (property);
-      jerry_length_t current_size = 0;
-      jerry_char_t string_buffer[64];
-      const jerry_length_t copy_size = (jerry_length_t) (sizeof (string_buffer) - 1);
+      jerry_value_t property = jerry_object_get_index (backtrace_array, idx);
 
       /* On some systems the uint32_t values can't be printed with "%u" and
        * on some systems it can be printed. To avoid differences in the uint32_t typdef
        * The "PRIu32" macro is used to correctly add the formatter.
        */
       jerry_port_log (JERRY_LOG_LEVEL_ERROR, " %" PRIu32 ": ", idx);
-      do
-      {
-        jerry_size_t copied_bytes = jerry_substring_to_utf8_char_buffer (property,
-                                                                         current_size,
-                                                                         current_size + copy_size,
-                                                                         string_buffer,
-                                                                         copy_size);
-        string_buffer[copied_bytes] = '\0';
-        jerry_port_log (JERRY_LOG_LEVEL_ERROR, "%s", string_buffer);
 
-        current_size += copied_bytes;
-      } while (total_size != current_size);
-      jerry_port_log (JERRY_LOG_LEVEL_ERROR, "\n");
+      jerry_char_t string_buffer[256];
+      const jerry_length_t buffer_size = (jerry_length_t) (sizeof (string_buffer) - 1);
 
-      jerry_release_value (property);
+      jerry_size_t copied_bytes = jerry_string_to_buffer (property, JERRY_ENCODING_UTF8, string_buffer, buffer_size);
+      string_buffer[copied_bytes] = '\0';
+
+      jerry_port_log (JERRY_LOG_LEVEL_ERROR, "%s\n", string_buffer);
+      jerry_value_free (property);
     }
 
-    jerry_release_value (backtrace_array);
+    jerry_value_free (backtrace_array);
   }
 
   jerry_port_fatal (ERR_FAILED_INTERNAL_ASSERTION);
@@ -104,10 +93,10 @@ jerryx_handler_assert_throw (const jerry_call_info_t *call_info_p, /**< call inf
 
   if (args_cnt == 1 && jerry_value_is_true (args_p[0]))
   {
-    return jerry_create_boolean (true);
+    return jerry_boolean (true);
   }
 
-  return jerry_create_error (JERRY_ERROR_COMMON, (jerry_char_t *) "assertion failed");
+  return jerry_throw_sz (JERRY_ERROR_COMMON, "assertion failed");
 } /* jerryx_handler_assert_throw */
 
 /**