Add bundle reading functions.

dulwich/bundle.py

@@ -0,0 +1,78 @@
+# bundle.py -- Bundle format support
+# Copyright (C) 2020 Jelmer Vernooij <jelmer@jelmer.uk>
+#
+# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
+# General Public License as public by the Free Software Foundation; version 2.0
+# or (at your option) any later version. You can redistribute it and/or
+# modify it under the terms of either of these two licenses.
+#
+# 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.
+#
+# You should have received a copy of the licenses; if not, see
+# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
+# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
+# License, Version 2.0.
+#
+
+"""Bundle format support.
+"""
+
+from .pack import PackData
+from typing import Dict, List, Tuple
+
+
+class Bundle(object):
+
+    version: int
+
+    capabilities: Dict[str, str]
+    prerequisites: List[Tuple[bytes, str]]
+    references: Dict[str, bytes]
+    pack_data: PackData
+
+
+def _read_bundle(f, version):
+    capabilities = {}
+    prerequisites = []
+    references = {}
+    line = f.readline()
+    if version >= 3:
+        while line.startswith(b'@'):
+            line = line[1:].rstrip(b'\n')
+            try:
+                key, value = line.split(b'=', 1)
+            except IndexError:
+                key = line
+                value = None
+            capabilities[key] = value
+            line = f.readline()
+    while line.startswith(b'-'):
+        (obj_id, comment) = line[1:].split(b' ', 1)
+        prerequisites.append((obj_id, comment.decode('utf-8')))
+        line = f.readline()
+    while line != b'\n':
+        (obj_id, ref) = line.rstrip(b'\n').split(b' ', 1)
+        references[ref] = obj_id
+        line = f.readline()
+    pack_data = PackData.from_file(f)
+    ret = Bundle()
+    ret.references = references
+    ret.capabilities = capabilities
+    ret.prerequisites = prerequisites
+    ret.pack_data = pack_data
+    return ret
+
+
+def read_bundle(f):
+    """Read a bundle file."""
+    firstline = f.readline()
+    if firstline == b'# v2 git bundle\n':
+        return _read_bundle(f, 2)
+    if firstline == b'# v3 git bundle\n':
+        return _read_bundle(f, 3)
+    raise AssertionError(
+        'unsupported bundle format header: %r' % firstline)

dulwich/pack.py

@@ -1056,7 +1056,7 @@ class PackData(object):
         return self._filename
 
     @classmethod
-    def from_file(cls, file, size):
+    def from_file(cls, file, size=None):
         return cls(str(file), file=file, size=size)
 
     @classmethod