Share some code between client and server

dulwich/protocol.py

@@ -0,0 +1,65 @@
+# protocol.py -- Shared parts of the git protocols
+# Copryight (C) 2008 John Carr <john.carr@unrouted.co.uk>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; version 2
+# of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+# MA  02110-1301, USA.
+
+
+class Protocol(object):
+
+    def __init__(self, read, write):
+        self.read = read
+        self.write = write
+
+    def read_pkt_line(self):
+        """
+        Reads a 'pkt line' from the remote git process
+
+        :return: The next string from the stream
+        """
+        sizestr = self.read(4)
+        if not sizestr:
+            return None
+        size = int(sizestr, 16)
+        if size == 0:
+            return None
+        return self.read(size-4)
+
+    def write_pkt_line(self, line):
+        """
+        Sends a 'pkt line' to the remote git process
+
+        :param line: A string containing the data to send
+        """
+        if line is None:
+            self.write("0000")
+        else:
+            self.write("%04x%s" % (len(line)+4, line))
+
+    def write_sideband(self, channel, blob):
+        """
+        Write data to the sideband (a git multiplexing method)
+
+        :param channel: int specifying which channel to write to
+        :param blob: a blob of data (as a string) to send on this channel
+        """
+        # a pktline can be a max of 65535. a sideband line can therefore be
+        # 65535-5 = 65530
+        # WTF: Why have the len in ASCII, but the channel in binary.
+        while blob:
+            self.write_pkt_line("%s%s" % (chr(channel), blob[:65530]))
+            blob = blob[65530:]
+
+