From 9e16820dd5d489444d1f7412923e3377e921416f Mon Sep 17 00:00:00 2001
From: INADA Naoki <inada-n@klab.com>
Date: Sat, 23 Aug 2014 03:34:14 +0900
Subject: [PATCH] Simplify MysqlPacket

---
 pymysql/connections.py | 97 +++++++++++++++++-------------------------
 1 file changed, 39 insertions(+), 58 deletions(-)

diff --git a/pymysql/connections.py b/pymysql/connections.py
index 3aa3a14..177fc03 100644
--- a/pymysql/connections.py
+++ b/pymysql/connections.py
@@ -232,37 +232,15 @@ def unpack_int64(n):
 
 
 class MysqlPacket(object):
-    """Representation of a MySQL response packet.  Reads in the packet
-    from the network socket, removes packet header and provides an interface
-    for reading/parsing the packet results."""
-    __slots__ = ('_position', '_data', '_packet_number')
+    """Representation of a MySQL response packet.
 
-    def __init__(self, connection):
+    Provides an interface for reading/parsing the packet results.
+    """
+    __slots__ = ('_position', '_data')
+
+    def __init__(self, data, encoding):
         self._position = 0
-        self._recv_packet(connection)
-
-    def _recv_packet(self, connection):
-        """Parse the packet header and read entire packet payload into buffer."""
-        buff = b''
-        while True:
-            packet_header = connection._read_bytes(4)
-            if DEBUG: dump_packet(packet_header)
-            packet_length_bin = packet_header[:3]
-
-            #TODO: check sequence id
-            self._packet_number = byte2int(packet_header[3])
-
-            bin_length = packet_length_bin + b'\0'  # pad little-endian number
-            bytes_to_read = struct.unpack('<I', bin_length)[0]
-            recv_data = connection._read_bytes(bytes_to_read)
-            if DEBUG: dump_packet(recv_data)
-            buff += recv_data
-            if bytes_to_read < MAX_PACKET_LEN:
-                break
-        self._data = buff
-
-    def packet_number(self):
-        return self._packet_number
+        self._data = data
 
     def get_all_data(self):
         return self._data
@@ -380,9 +358,9 @@ class FieldDescriptorPacket(MysqlPacket):
     attributes on the class such as: db, table_name, name, length, type_code.
     """
 
-    def __init__(self, connection):
-        MysqlPacket.__init__(self, connection)
-        self.__parse_field_descriptor(connection.encoding)
+    def __init__(self, data, encoding):
+        MysqlPacket.__init__(self, data, encoding)
+        self.__parse_field_descriptor(encoding)
 
     def __parse_field_descriptor(self, encoding):
         """Parse the 'Field Descriptor' (Metadata) packet.
@@ -402,27 +380,19 @@ class FieldDescriptorPacket(MysqlPacket):
         self.flags = struct.unpack('<H', self.read(2))[0]
         self.scale = byte2int(self.read(1))  # "decimals"
         self.advance(2)  # filler (always 0x00)
-
         # 'default' is a length coded binary and is still in the buffer?
         # not used for normal result sets...
 
     def description(self):
         """Provides a 7-item tuple compatible with the Python PEP249 DB Spec."""
-        desc = []
-        desc.append(self.name)
-        desc.append(self.type_code)
-        desc.append(None) # TODO: display_length; should this be self.length?
-        desc.append(self.get_column_length()) # 'internal_size'
-        desc.append(self.get_column_length()) # 'precision'  # TODO: why!?!?
-        desc.append(self.scale)
-
-        # 'null_ok' -- can this be True/False rather than 1/0?
-        #              if so just do:  desc.append(bool(self.flags % 2 == 0))
-        if self.flags % 2 == 0:
-            desc.append(1)
-        else:
-            desc.append(0)
-        return tuple(desc)
+        return (
+            self.name,
+            self.type_code,
+            None,  # TODO: display_length; should this be self.length?
+            self.get_column_length(),  # 'internal_size'
+            self.get_column_length(),  # 'precision'  # TODO: why!?!?
+            self.scale,
+            self.flags % 2 == 0)
 
     def get_column_length(self):
         if self.type_code == FIELD_TYPE.VAR_STRING:
@@ -840,7 +810,24 @@ class Connection(object):
         """Read an entire "mysql packet" in its entirety from the network
         and return a MysqlPacket type that represents the results.
         """
-        packet = packet_type(self)
+        buff = b''
+        while True:
+            packet_header = self._read_bytes(4)
+            if DEBUG: dump_packet(packet_header)
+            packet_length_bin = packet_header[:3]
+
+            #TODO: check sequence id
+            #  packet_number
+            byte2int(packet_header[3])
+
+            bin_length = packet_length_bin + b'\0'  # pad little-endian number
+            bytes_to_read = struct.unpack('<I', bin_length)[0]
+            recv_data = self._read_bytes(bytes_to_read)
+            if DEBUG: dump_packet(recv_data)
+            buff += recv_data
+            if bytes_to_read < MAX_PACKET_LEN:
+                break
+        packet = packet_type(buff, self.encoding)
         packet.check_error()
         return packet
 
@@ -968,9 +955,7 @@ class Connection(object):
 
         self._write_bytes(data)
 
-        auth_packet = MysqlPacket(self)
-        auth_packet.check_error()
-        if DEBUG: auth_packet.dump()
+        auth_packet = self._read_packet()
 
         # if old_passwords is enabled the packet will be 1 byte long and
         # have the octet 254
@@ -979,11 +964,8 @@ class Connection(object):
             # send legacy handshake
             data = _scramble_323(self.password.encode('latin1'), self.salt) + b'\0'
             data = pack_int24(len(data)) + int2byte(next_packet) + data
-
             self._write_bytes(data)
-            auth_packet = MysqlPacket(self)
-            auth_packet.check_error()
-            if DEBUG: auth_packet.dump()
+            auth_packet = self._read_packet()
 
     # _mysql support
     def thread_id(self):
@@ -1000,8 +982,7 @@ class Connection(object):
 
     def _get_server_information(self):
         i = 0
-        packet = MysqlPacket(self)
-        packet.check_error()
+        packet = self._read_packet()
         data = packet.get_all_data()
 
         if DEBUG: dump_packet(data)