[Debugger] Create a simplified transmission layer (#2781)

It supports the raw packet sending over a TCP/IP protocol

JerryScript-DCO-1.0-Signed-off-by: Robert Sipka rsipka.uszeged@partner.samsung.com

jerry-debugger/jerry_client_rawpacket.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python
+
+# 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.
+
+import struct
+
+MAX_BUFFER_SIZE = 256
+
+class RawPacket(object):
+    """ Simplified transmission layer. """
+    def __init__(self, address, protocol):
+        self.protocol = protocol
+        self.data_buffer = b""
+        self.address = address
+
+    def connect(self, config_size):
+        """  Create connection. """
+        self.protocol.connect(self.address)
+        self.data_buffer = b""
+
+        # It will return with the Network configurations, which has the following struct:
+        # header [1] - size[1]
+        # configuration [config_size]
+        len_expected = config_size + 1
+
+        while len(self.data_buffer) < len_expected:
+            self.data_buffer += self.protocol.receive_data()
+
+        expected = struct.pack("B", config_size)
+
+        if self.data_buffer[0:1] != expected:
+            raise Exception("Unexpected configuration")
+
+        result = self.data_buffer[1:len_expected]
+        self.data_buffer = self.data_buffer[len_expected:]
+
+        return result
+
+    def close(self):
+        """ Close connection. """
+        self.protocol.close()
+
+    def send_message(self, _, data):
+        """ Send message. """
+        msg_size = len(data)
+
+        while msg_size > 0:
+            bytes_send = self.protocol.send_data(data)
+            if bytes_send < msg_size:
+                data = data[bytes_send:]
+            msg_size -= bytes_send
+
+    def get_message(self, blocking):
+        """ Receive message. """
+
+        # Connection was closed
+        if self.data_buffer is None:
+            return None
+
+        while True:
+            if len(self.data_buffer) >= 1:
+                size = ord(self.data_buffer[0])
+                if size == 0:
+                    raise Exception("Unexpected data frame")
+
+                if len(self.data_buffer) >= size + 1:
+                    result = self.data_buffer[1:size + 1]
+                    self.data_buffer = self.data_buffer[size + 1:]
+                    return result
+
+            if not blocking and not self.protocol.ready():
+                return b''
+
+            received_data = self.protocol.receive_data(MAX_BUFFER_SIZE)
+
+            if not received_data:
+                return None
+
+            self.data_buffer += received_data