Convert connections attribute to list

docs/examples/edit_rosbags_edit_timestamps.py

@@ -23,7 +23,7 @@ def offset_timestamps(src: Path, dst: Path, offset: int) -> None:
     """
     with Reader(src) as reader, Writer(dst) as writer:
         conn_map = {}
-        for conn in reader.connections.values():
+        for conn in reader.connections:
             ext = cast(ConnectionExtRosbag2, conn.ext)
             conn_map[conn.id] = writer.add_connection(
                 conn.topic,

docs/examples/edit_rosbags_remove_topic.py

@@ -22,7 +22,7 @@ def remove_topic(src: Path, dst: Path, topic: str) -> None:
     """
     with Reader(src) as reader, Writer(dst) as writer:
         conn_map = {}
-        for conn in reader.connections.values():
+        for conn in reader.connections:
             if conn.topic == topic:
                 continue
             ext = cast(ConnectionExtRosbag2, conn.ext)

docs/examples/register_types_rosbag1.py

@@ -20,7 +20,7 @@ def process_bag(src: Path) -> None:
     """
     with Reader(src) as reader:
         typs = {}
-        for conn in reader.connections.values():
+        for conn in reader.connections:
             typs.update(get_types_from_msg(conn.msgdef, conn.msgtype))
         register_types(typs)
 

docs/topics/rosbag1.rst

@@ -37,8 +37,8 @@ Instances of the :py:class:`Reader <rosbags.rosbag2.Reader>` class are typically
 
    # create reader instance
    with Reader('/home/ros/rosbag_2020_03_24.bag') as reader:
-       # topic and msgtype information is available on .connections dictionary
+       # topic and msgtype information is available on .connections list
-       for connection in reader.connections.values():
+       for connection in reader.connections:
            print(connection.topic, connection.msgtype)
 
        # iterate over messages
@@ -48,7 +48,7 @@ Instances of the :py:class:`Reader <rosbags.rosbag2.Reader>` class are typically
                print(msg.header.frame_id)
 
        # messages() accepts connection filters
-       connections = [x for x in reader.connections.values() if x.topic == '/imu_raw/Imu']
+       connections = [x for x in reader.connections if x.topic == '/imu_raw/Imu']
        for connection, timestamp, rawdata in reader.messages(connections=connections):
            msg = deserialize_cdr(ros1_to_cdr(rawdata, connection.msgtype), connection.msgtype)
            print(msg.header.frame_id)

docs/topics/rosbag2.rst

@@ -52,8 +52,8 @@ Instances of the :py:class:`Reader <rosbags.rosbag2.Reader>` class are used to r
 
    # create reader instance and open for reading
    with Reader('/home/ros/rosbag_2020_03_24') as reader:
-       # topic and msgtype information is available on .connections dict
+       # topic and msgtype information is available on .connections list
-       for connection in reader.connections.values():
+       for connection in reader.connections:
            print(connection.topic, connection.msgtype)
 
        # iterate over messages
@@ -63,7 +63,7 @@ Instances of the :py:class:`Reader <rosbags.rosbag2.Reader>` class are used to r
                print(msg.header.frame_id)
 
        # messages() accepts connection filters
-       connections = [x for x in reader.connections.values() if x.topic == '/imu_raw/Imu']
+       connections = [x for x in reader.connections if x.topic == '/imu_raw/Imu']
        for connection, timestamp, rawdata in reader.messages(connections=connections):
            msg = deserialize_cdr(rawdata, connection.msgtype)
            print(msg.header.frame_id)

src/rosbags/convert/converter.py

@@ -111,10 +111,10 @@ def convert_1to2(src: Path, dst: Path) -> None:
         typs: dict[str, Any] = {}
         connmap: dict[int, Connection] = {}
 
-        for rconn in reader.connections.values():
+        for rconn in reader.connections:
             candidate = upgrade_connection(rconn)
             assert isinstance(candidate.ext, ConnectionExtRosbag2)
-            for conn in writer.connections.values():
+            for conn in writer.connections:
                 assert isinstance(conn.ext, ConnectionExtRosbag2)
                 if (
                     conn.topic == candidate.topic and conn.msgtype == candidate.msgtype and
@@ -147,10 +147,10 @@ def convert_2to1(src: Path, dst: Path) -> None:
     """
     with Reader2(src) as reader, Writer1(dst) as writer:
         connmap: dict[int, Connection] = {}
-        for rconn in reader.connections.values():
+        for rconn in reader.connections:
             candidate = downgrade_connection(rconn)
             assert isinstance(candidate.ext, ConnectionExtRosbag1)
-            for conn in writer.connections.values():
+            for conn in writer.connections:
                 assert isinstance(conn.ext, ConnectionExtRosbag1)
                 if (
                     conn.topic == candidate.topic and conn.md5sum == candidate.md5sum and

src/rosbags/highlevel/anyreader.py

@@ -143,11 +143,11 @@ class AnyReader:
             typs: dict[str, Any] = {}
             for reader in self.readers:
                 assert isinstance(reader, Reader1)
-                for connection in reader.connections.values():
+                for connection in reader.connections:
                     typs.update(get_types_from_msg(connection.msgdef, connection.msgtype))
             register_types(typs, self.typestore)
 
-        self.connections = [y for x in self.readers for y in x.connections.values()]
+        self.connections = [y for x in self.readers for y in x.connections]
         self.isopen = True
 
     def close(self) -> None:

src/rosbags/rosbag1/reader.py

@@ -342,7 +342,7 @@ class Reader:
             raise ReaderError(f'File {str(self.path)!r} does not exist.')
 
         self.bio: Optional[BinaryIO] = None
-        self.connections: dict[int, Connection] = {}
+        self.connections: list[Connection] = []
         self.indexes: dict[int, list[IndexData]]
         self.chunk_infos: list[ChunkInfo] = []
         self.chunks: dict[int, Chunk] = {}
@@ -384,7 +384,7 @@ class Reader:
 
             self.bio.seek(index_pos)
             try:
-                self.connections = dict(self.read_connection() for _ in range(conn_count))
+                self.connections = [self.read_connection() for _ in range(conn_count)]
                 self.chunk_infos = [self.read_chunk_info() for _ in range(chunk_count)]
             except ReaderError as err:
                 raise ReaderError(f'Bag index looks damaged: {err.args}') from None
@@ -402,14 +402,15 @@ class Reader:
             self.indexes = {
                 cid: list(heapq.merge(*x, key=lambda x: x.time)) for cid, x in indexes.items()
             }
-            assert all(self.indexes[x] for x in self.connections)
+            assert all(self.indexes[x.id] for x in self.connections)
 
-            for cid, connection in self.connections.items():
+            self.connections = [
-                self.connections[cid] = Connection(
+                Connection(
-                    *connection[0:5],
+                    *x[0:5],
-                    len(self.indexes[cid]),
+                    len(self.indexes[x.id]),
-                    *connection[6:],
+                    *x[6:],
-                )
+                ) for x in self.connections
+            ]
         except ReaderError:
             self.close()
             raise
@@ -445,7 +446,7 @@ class Reader:
         """Topic information."""
         topics = {}
         for topic, group in groupby(
-            sorted(self.connections.values(), key=lambda x: x.topic),
+            sorted(self.connections, key=lambda x: x.topic),
             key=lambda x: x.topic,
         ):
             connections = list(group)
@@ -462,7 +463,7 @@ class Reader:
             )
         return topics
 
-    def read_connection(self) -> tuple[int, Connection]:
+    def read_connection(self) -> Connection:
         """Read connection record from current position."""
         assert self.bio
         header = Header.read(self.bio, RecordType.CONNECTION)
@@ -477,7 +478,7 @@ class Reader:
         callerid = header.get_string('callerid') if 'callerid' in header else None
         latching = int(header.get_string('latching')) if 'latching' in header else None
 
-        return conn, Connection(
+        return Connection(
             conn,
             topic,
             normalize_msgtype(typ),
@@ -593,7 +594,9 @@ class Reader:
             raise ReaderError('Rosbag is not open.')
 
         if not connections:
-            connections = self.connections.values()
+            connections = self.connections
+
+        connmap = {x.id: x for x in self.connections}
 
         indexes = [self.indexes[x.id] for x in connections]
         for entry in heapq.merge(*indexes):
@@ -624,7 +627,7 @@ class Reader:
                 raise ReaderError('Expected to find message data.')
 
             data = read_bytes(chunk, read_uint32(chunk))
-            connection = self.connections[header.get_uint32('conn')]
+            connection = connmap[header.get_uint32('conn')]
             assert entry.time == header.get_time('time')
             yield connection, entry.time, data
 

src/rosbags/rosbag1/writer.py

@@ -159,7 +159,7 @@ class Writer:
         self.bio: Optional[BinaryIO] = None
         self.compressor: Callable[[bytes], bytes] = lambda x: x
         self.compression_format = 'none'
-        self.connections: dict[int, Connection] = {}
+        self.connections: list[Connection] = []
         self.chunks: list[WriteChunk] = [
             WriteChunk(BytesIO(), -1, 2**64, 0, defaultdict(list)),
         ]
@@ -258,7 +258,7 @@ class Writer:
             self,
         )
 
-        if any(x[1:] == connection[1:] for x in self.connections.values()):
+        if any(x[1:] == connection[1:] for x in self.connections):
             raise WriterError(
                 f'Connections can only be added once with same arguments: {connection!r}.',
             )
@@ -266,7 +266,7 @@ class Writer:
         bio = self.chunks[-1].data
         self.write_connection(connection, bio)
 
-        self.connections[connection.id] = connection
+        self.connections.append(connection)
         return connection
 
     def write(self, connection: Connection, timestamp: int, data: bytes) -> None:
@@ -284,7 +284,7 @@ class Writer:
         if not self.bio:
             raise WriterError('Bag was not opened.')
 
-        if connection not in self.connections.values():
+        if connection not in self.connections:
             raise WriterError(f'There is no connection {connection!r}.') from None
 
         chunk = self.chunks[-1]
@@ -367,7 +367,7 @@ class Writer:
 
         index_pos = self.bio.tell()
 
-        for connection in self.connections.values():
+        for connection in self.connections:
             self.write_connection(connection, self.bio)
 
         for chunk in self.chunks:

src/rosbags/rosbag2/reader.py

@@ -136,8 +136,8 @@ class Reader:
             if missing := [x for x in self.paths if not x.exists()]:
                 raise ReaderError(f'Some database files are missing: {[str(x) for x in missing]!r}')
 
-            self.connections = {
+            self.connections = [
-                idx + 1: Connection(
+                Connection(
                     id=idx + 1,
                     topic=x['topic_metadata']['name'],
                     msgtype=x['topic_metadata']['type'],
@@ -150,9 +150,9 @@ class Reader:
                     ),
                     owner=self,
                 ) for idx, x in enumerate(self.metadata['topics_with_message_count'])
-            }
+            ]
             noncdr = {
-                fmt for x in self.connections.values() if isinstance(x.ext, ConnectionExtRosbag2)
+                fmt for x in self.connections if isinstance(x.ext, ConnectionExtRosbag2)
                 if (fmt := x.ext.serialization_format) != 'cdr'
             }
             if noncdr:
@@ -209,10 +209,7 @@ class Reader:
     @property
     def topics(self) -> dict[str, TopicInfo]:
         """Topic information."""
-        return {
+        return {x.topic: TopicInfo(x.msgtype, x.msgdef, x.msgcount, [x]) for x in self.connections}
-            x.topic: TopicInfo(x.msgtype, x.msgdef, x.msgcount, [x])
-            for x in self.connections.values()
-        }
 
     def messages(  # pylint: disable=too-many-locals
         self,
@@ -278,7 +275,7 @@ class Reader:
 
                 cur.execute('SELECT name,id FROM topics')
                 connmap: dict[int, Connection] = {
-                    row[1]: next((x for x in self.connections.values() if x.topic == row[0]),
+                    row[1]: next((x for x in self.connections if x.topic == row[0]),
                                  None)  # type: ignore
                     for row in cur
                 }

src/rosbags/rosbag2/writer.py

@@ -81,7 +81,7 @@ class Writer:  # pylint: disable=too-many-instance-attributes
         self.compression_mode = ''
         self.compression_format = ''
         self.compressor: Optional[zstandard.ZstdCompressor] = None
-        self.connections: dict[int, Connection] = {}
+        self.connections: list[Connection] = []
         self.counts: dict[int, int] = {}
         self.conn: Optional[sqlite3.Connection] = None
         self.cursor: Optional[sqlite3.Cursor] = None
@@ -152,7 +152,7 @@ class Writer:  # pylint: disable=too-many-instance-attributes
             raise WriterError('Bag was not opened.')
 
         connection = Connection(
-            id=len(self.connections.values()) + 1,
+            id=len(self.connections) + 1,
             topic=topic,
             msgtype=msgtype,
             msgdef='',
@@ -164,14 +164,14 @@ class Writer:  # pylint: disable=too-many-instance-attributes
             ),
             owner=self,
         )
-        for conn in self.connections.values():
+        for conn in self.connections:
             if (
                 conn.topic == connection.topic and conn.msgtype == connection.msgtype and
                 conn.ext == connection.ext
             ):
                 raise WriterError(f'Connection can only be added once: {connection!r}.')
 
-        self.connections[connection.id] = connection
+        self.connections.append(connection)
         self.counts[connection.id] = 0
         meta = (connection.id, topic, msgtype, serialization_format, offered_qos_profiles)
         self.cursor.execute('INSERT INTO topics VALUES(?, ?, ?, ?, ?)', meta)
@@ -191,7 +191,7 @@ class Writer:  # pylint: disable=too-many-instance-attributes
         """
         if not self.cursor:
             raise WriterError('Bag was not opened.')
-        if connection not in self.connections.values():
+        if connection not in self.connections:
             raise WriterError(f'Tried to write to unknown connection {connection!r}.')
 
         if self.compression_mode == 'message':
@@ -252,7 +252,7 @@ class Writer:  # pylint: disable=too-many-instance-attributes
                             'offered_qos_profiles': x.ext.offered_qos_profiles,
                         },
                         'message_count': self.counts[x.id],
-                    } for x in self.connections.values() if isinstance(x.ext, ConnectionExtRosbag2)
+                    } for x in self.connections if isinstance(x.ext, ConnectionExtRosbag2)
                 ],
                 'compression_format': self.compression_format,
                 'compression_mode': self.compression_mode,

tests/test_convert.py

@@ -146,12 +146,12 @@ def test_convert_1to2(tmp_path: Path) -> None:
             Connection(3, '/other', 'typ', '', '', -1, ConnectionExtRosbag2('cdr', ''), None),
         ]
 
-        readerinst.connections = {
+        readerinst.connections = [
-            1: connections[0],
+            connections[0],
-            2: connections[1],
+            connections[1],
-            3: connections[2],
+            connections[2],
-            4: connections[3],
+            connections[3],
-        }
+        ]
 
         readerinst.messages.return_value = [
             (connections[0], 42, b'\x42'),
@@ -160,14 +160,13 @@ def test_convert_1to2(tmp_path: Path) -> None:
             (connections[3], 45, b'\x45'),
         ]
 
-        writerinst.connections = {}
+        writerinst.connections = []
 
         def add_connection(*_: Any) -> Connection:  # noqa: ANN401
             """Mock for Writer.add_connection."""
-            writerinst.connections = {
+            writerinst.connections = [
-                conn.id: conn
+                conn for _, conn in zip(range(len(writerinst.connections) + 1), wconnections)
-                for _, conn in zip(range(len(writerinst.connections) + 1), wconnections)
+            ]
-            }
             return wconnections[len(writerinst.connections) - 1]
 
         writerinst.add_connection.side_effect = add_connection
@@ -311,12 +310,12 @@ def test_convert_2to1(tmp_path: Path) -> None:
             ),
         ]
 
-        readerinst.connections = {
+        readerinst.connections = [
-            1: connections[0],
+            connections[0],
-            2: connections[1],
+            connections[1],
-            3: connections[2],
+            connections[2],
-            4: connections[3],
+            connections[3],
-        }
+        ]
 
         readerinst.messages.return_value = [
             (connections[0], 42, b'\x42'),
@@ -325,14 +324,13 @@ def test_convert_2to1(tmp_path: Path) -> None:
             (connections[3], 45, b'\x45'),
         ]
 
-        writerinst.connections = {}
+        writerinst.connections = []
 
         def add_connection(*_: Any) -> Connection:  # noqa: ANN401
             """Mock for Writer.add_connection."""
-            writerinst.connections = {
+            writerinst.connections = [
-                conn.id: conn
+                conn for _, conn in zip(range(len(writerinst.connections) + 1), wconnections)
-                for _, conn in zip(range(len(writerinst.connections) + 1), wconnections)
+            ]
-            }
             return wconnections[len(writerinst.connections) - 1]
 
         writerinst.add_connection.side_effect = add_connection

tests/test_reader.py

@@ -126,7 +126,7 @@ def test_reader(bag: Path) -> None:
         assert reader.message_count == 4
         if reader.compression_mode:
             assert reader.compression_format == 'zstd'
-        assert [*reader.connections.keys()] == [1, 2, 3]
+        assert [x.id for x in reader.connections] == [1, 2, 3]
         assert [*reader.topics.keys()] == ['/poly', '/magn', '/joint']
         gen = reader.messages()
 
@@ -154,7 +154,7 @@ def test_reader(bag: Path) -> None:
 def test_message_filters(bag: Path) -> None:
     """Test reader filters messages."""
     with Reader(bag) as reader:
-        magn_connections = [x for x in reader.connections.values() if x.topic == '/magn']
+        magn_connections = [x for x in reader.connections if x.topic == '/magn']
         gen = reader.messages(connections=magn_connections)
         connection, _, _ = next(gen)
         assert connection.topic == '/magn'

tests/test_reader1.py

@@ -274,7 +274,7 @@ def test_reader(tmp_path: Path) -> None:  # pylint: disable=too-many-statements
         assert msgs[0][2] == b'MSGCONTENT5'
         assert msgs[1][2] == b'MSGCONTENT10'
 
-        connections = [x for x in reader.connections.values() if x.topic == '/topic0']
+        connections = [x for x in reader.connections if x.topic == '/topic0']
         msgs = list(reader.messages(connections))
         assert len(msgs) == 1
         assert msgs[0][2] == b'MSGCONTENT10'