Merge upstream
[jelmer/dulwich-libgit2.git] / dulwich / server.py
1 # server.py -- Implementation of the server side git protocols
2 # Copryight (C) 2008 John Carr <john.carr@unrouted.co.uk>
3 #
4 # This program is free software; you can redistribute it and/or
5 # modify it under the terms of the GNU General Public License
6 # as published by the Free Software Foundation; version 2
7 # or (at your option) any later version of the License.
8 #
9 # This program is distributed in the hope that it will be useful,
10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 # GNU General Public License for more details.
13 #
14 # You should have received a copy of the GNU General Public License
15 # along with this program; if not, write to the Free Software
16 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
17 # MA  02110-1301, USA.
18
19 import SocketServer
20 from dulwich.protocol import Protocol, ProtocolFile, TCP_GIT_PORT, extract_capabilities
21 from dulwich.repo import Repo
22 from dulwich.pack import write_pack_data
23 import tempfile
24
25 class Backend(object):
26
27     def get_refs(self):
28         """
29         Get all the refs in the repository
30
31         :return: dict of name -> sha
32         """
33         raise NotImplementedError
34
35     def apply_pack(self, refs, read):
36         """ Import a set of changes into a repository and update the refs
37
38         :param refs: list of tuple(name, sha)
39         :param read: callback to read from the incoming pack
40         """
41         raise NotImplementedError
42
43     def fetch_objects(self, determine_wants, graph_walker, progress):
44         """
45         Yield the objects required for a list of commits.
46
47         :param progress: is a callback to send progress messages to the client
48         """
49         raise NotImplementedError
50
51
52 class GitBackend(Backend):
53
54     def __init__(self, gitdir=None):
55         self.gitdir = gitdir
56
57         if not self.gitdir:
58             self.gitdir = tempfile.mkdtemp()
59             Repo.create(self.gitdir)
60
61         self.repo = Repo(self.gitdir)
62         self.fetch_objects = self.repo.fetch_objects
63         self.get_refs = self.repo.get_refs
64
65     def apply_pack(self, refs, read):
66         fd, commit = self.repo.object_store.add_pack()
67         fd.write(read())
68         fd.close()
69         commit()
70
71         for oldsha, sha, ref in refs:
72             if ref == "0" * 40:
73                 self.repo.remove_ref(ref)
74             else:
75                 self.repo.set_ref(ref, sha)
76
77         print "pack applied"
78
79
80 class Handler(object):
81
82     def __init__(self, backend, read, write):
83         self.backend = backend
84         self.proto = Protocol(read, write)
85
86     def capabilities(self):
87         return " ".join(self.default_capabilities())
88
89
90 class UploadPackHandler(Handler):
91
92     def default_capabilities(self):
93         return ("multi_ack", "side-band-64k", "thin-pack", "ofs-delta")
94
95     def handle(self):
96         def determine_wants(heads):
97             keys = heads.keys()
98             if keys:
99                 self.proto.write_pkt_line("%s %s\x00%s\n" % ( heads[keys[0]], keys[0], self.capabilities()))
100                 for k in keys[1:]:
101                     self.proto.write_pkt_line("%s %s\n" % (heads[k], k))
102
103             # i'm done..
104             self.proto.write("0000")
105
106             # Now client will either send "0000", meaning that it doesnt want to pull.
107             # or it will start sending want want want commands
108             want = self.proto.read_pkt_line()
109             if want == None:
110                 return []
111
112             want, self.client_capabilities = extract_capabilities(want)
113
114             want_revs = []
115             while want and want[:4] == 'want':
116                 want_revs.append(want[5:45])
117                 want = self.proto.read_pkt_line()
118             return want_revs
119
120         progress = lambda x: self.proto.write_sideband(2, x)
121         write = lambda x: self.proto.write_sideband(1, x)
122
123         class ProtocolGraphWalker(object):
124
125             def __init__(self, proto):
126                 self.proto = proto
127                 self._last_sha = None
128
129             def ack(self, have_ref):
130                 self.proto.write_pkt_line("ACK %s continue\n" % have_ref)
131
132             def next(self):
133                 have = self.proto.read_pkt_line()
134                 if have[:4] == 'have':
135                     return have[5:45]
136
137                 #if have[:4] == 'done':
138                 #    return None
139
140                 if self._last_sha:
141                     # Oddness: Git seems to resend the last ACK, without the "continue" statement
142                     self.proto.write_pkt_line("ACK %s\n" % self._last_sha)
143
144                 # The exchange finishes with a NAK
145                 self.proto.write_pkt_line("NAK\n")
146
147         graph_walker = ProtocolGraphWalker(self.proto)
148         objects = list(self.backend.fetch_objects(determine_wants, graph_walker, progress))
149         progress("dul-daemon says what\n")
150         progress("counting objects: %d, done.\n" % len(objects))
151         write_pack_data(ProtocolFile(None, write), objects, len(objects))
152         progress("how was that, then?\n")
153         # we are done
154         self.proto.write("0000")
155
156
157 class ReceivePackHandler(Handler):
158
159     def default_capabilities(self):
160         return ("report-status", "delete-refs")
161
162     def handle(self):
163         refs = self.backend.get_refs().items()
164
165         if refs:
166             self.proto.write_pkt_line("%s %s\x00%s\n" % (refs[0][1], refs[0][0], self.capabilities()))
167             for i in range(1, len(refs)):
168                 ref = refs[i]
169                 self.proto.write_pkt_line("%s %s\n" % (ref[1], ref[0]))
170         else:
171             self.proto.write_pkt_line("0000000000000000000000000000000000000000 capabilities^{} %s" % self.capabilities())
172
173         self.proto.write("0000")
174
175         client_refs = []
176         ref = self.proto.read_pkt_line()
177
178         # if ref is none then client doesnt want to send us anything..
179         if ref is None:
180             return
181
182         ref, client_capabilities = extract_capabilities(ref)
183
184         # client will now send us a list of (oldsha, newsha, ref)
185         while ref:
186             client_refs.append(ref.split())
187             ref = self.proto.read_pkt_line()
188
189         # backend can now deal with this refs and read a pack using self.read
190         self.backend.apply_pack(client_refs, self.proto.read)
191
192         # when we have read all the pack from the client, it assumes everything worked OK
193         # there is NO ack from the server before it reports victory.
194
195
196 class TCPGitRequestHandler(SocketServer.StreamRequestHandler):
197
198     def handle(self):
199         proto = Protocol(self.rfile.read, self.wfile.write)
200         command, args = proto.read_cmd()
201
202         # switch case to handle the specific git command
203         if command == 'git-upload-pack':
204             cls = UploadPackHandler
205         elif command == 'git-receive-pack':
206             cls = ReceivePackHandler
207         else:
208             return
209
210         h = cls(self.server.backend, self.rfile.read, self.wfile.write)
211         h.handle()
212
213
214 class TCPGitServer(SocketServer.TCPServer):
215
216     allow_reuse_address = True
217     serve = SocketServer.TCPServer.serve_forever
218
219     def __init__(self, backend, listen_addr, port=TCP_GIT_PORT):
220         self.backend = backend
221         SocketServer.TCPServer.__init__(self, (listen_addr, port), TCPGitRequestHandler)
222
223