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 # 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         commit()
69
70         for oldsha, sha, ref in refs:
71             if ref == "0" * 40:
72                 self.repo.remove_ref(ref)
73             else:
74                 self.repo.set_ref(ref, sha)
75
76         print "pack applied"
77
78
79 class Handler(object):
80
81     def __init__(self, backend, read, write):
82         self.backend = backend
83         self.proto = Protocol(read, write)
84
85     def capabilities(self):
86         return " ".join(self.default_capabilities())
87
88
89 class UploadPackHandler(Handler):
90
91     def default_capabilities(self):
92         return ("multi_ack", "side-band-64k", "thin-pack", "ofs-delta")
93
94     def handle(self):
95         def determine_wants(heads):
96             keys = heads.keys()
97             if keys:
98                 self.proto.write_pkt_line("%s %s\x00%s\n" % ( heads[keys[0]], keys[0], self.capabilities()))
99                 for k in keys[1:]:
100                     self.proto.write_pkt_line("%s %s\n" % (heads[k], k))
101
102             # i'm done..
103             self.proto.write("0000")
104
105             # Now client will either send "0000", meaning that it doesnt want to pull.
106             # or it will start sending want want want commands
107             want = self.proto.read_pkt_line()
108             if want == None:
109                 return []
110
111             want, self.client_capabilities = extract_capabilities(want)
112
113             want_revs = []
114             while want and want[:4] == 'want':
115                 want_revs.append(want[5:45])
116                 want = self.proto.read_pkt_line()
117             return want_revs
118
119         progress = lambda x: self.proto.write_sideband(2, x)
120         write = lambda x: self.proto.write_sideband(1, x)
121
122         class ProtocolGraphWalker(object):
123
124             def __init__(self, proto):
125                 self.proto = proto
126                 self._last_sha = None
127
128             def ack(self, have_ref):
129                 self.proto.write_pkt_line("ACK %s continue\n" % have_ref)
130
131             def next(self):
132                 have = self.proto.read_pkt_line()
133                 if have[:4] == 'have':
134                     return have[5:45]
135
136                 #if have[:4] == 'done':
137                 #    return None
138
139                 if self._last_sha:
140                     # Oddness: Git seems to resend the last ACK, without the "continue" statement
141                     self.proto.write_pkt_line("ACK %s\n" % self._last_sha)
142
143                 # The exchange finishes with a NAK
144                 self.proto.write_pkt_line("NAK\n")
145
146         graph_walker = ProtocolGraphWalker(self.proto)
147         objects = list(self.backend.fetch_objects(determine_wants, graph_walker, progress))
148         progress("dul-daemon says what\n")
149         progress("counting objects: %d, done.\n" % len(objects))
150         write_pack_data(ProtocolFile(None, write), objects, len(objects))
151         progress("how was that, then?\n")
152         # we are done
153         self.proto.write("0000")
154
155
156 class ReceivePackHandler(Handler):
157
158     def default_capabilities(self):
159         return ("report-status", "delete-refs")
160
161     def handle(self):
162         refs = self.backend.get_refs().items()
163
164         if refs:
165             self.proto.write_pkt_line("%s %s\x00%s\n" % (refs[0][1], refs[0][0], self.capabilities()))
166             for i in range(1, len(refs)):
167                 ref = refs[i]
168                 self.proto.write_pkt_line("%s %s\n" % (ref[1], ref[0]))
169         else:
170             self.proto.write_pkt_line("0000000000000000000000000000000000000000 capabilities^{} %s" % self.capabilities())
171
172         self.proto.write("0000")
173
174         client_refs = []
175         ref = self.proto.read_pkt_line()
176
177         # if ref is none then client doesnt want to send us anything..
178         if ref is None:
179             return
180
181         ref, client_capabilities = extract_capabilities(ref)
182
183         # client will now send us a list of (oldsha, newsha, ref)
184         while ref:
185             client_refs.append(ref.split())
186             ref = self.proto.read_pkt_line()
187
188         # backend can now deal with this refs and read a pack using self.read
189         self.backend.apply_pack(client_refs, self.proto.read)
190
191         # when we have read all the pack from the client, it assumes everything worked OK
192         # there is NO ack from the server before it reports victory.
193
194
195 class TCPGitRequestHandler(SocketServer.StreamRequestHandler):
196
197     def handle(self):
198         proto = Protocol(self.rfile.read, self.wfile.write)
199         command, args = proto.read_cmd()
200
201         # switch case to handle the specific git command
202         if command == 'git-upload-pack':
203             cls = UploadPackHandler
204         elif command == 'git-receive-pack':
205             cls = ReceivePackHandler
206         else:
207             return
208
209         h = cls(self.server.backend, self.rfile.read, self.wfile.write)
210         h.handle()
211
212
213 class TCPGitServer(SocketServer.TCPServer):
214
215     allow_reuse_address = True
216     serve = SocketServer.TCPServer.serve_forever
217
218     def __init__(self, backend, listen_addr, port=TCP_GIT_PORT):
219         self.backend = backend
220         SocketServer.TCPServer.__init__(self, (listen_addr, port), TCPGitRequestHandler)
221
222