aboutsummaryrefslogtreecommitdiff
path: root/matrix/history.go
blob: 1b99125bbd7a0fa541d528b4f23fc75b4da1a9bf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2019 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package matrix

import (
	"bytes"
	"encoding/binary"
	"encoding/gob"
	"sync"

	bolt "go.etcd.io/bbolt"

	"maunium.net/go/gomuks/matrix/rooms"
	"maunium.net/go/mautrix"
)

type HistoryManager struct {
	sync.Mutex

	db *bolt.DB

	historyEndPtr  map[*rooms.Room]uint64
	historyLoadPtr map[*rooms.Room]uint64
}

var bucketRoomStreams = []byte("room_streams")
var bucketRoomEventIDs = []byte("room_event_ids")
var bucketStreamPointers = []byte("room_stream_pointers")

const halfUint64 = ^uint64(0) >> 1

func NewHistoryManager(dbPath string) (*HistoryManager, error) {
	hm := &HistoryManager{
		historyEndPtr:  make(map[*rooms.Room]uint64),
		historyLoadPtr: make(map[*rooms.Room]uint64),
	}
	db, err := bolt.Open(dbPath, 0600, nil)
	if err != nil {
		return nil, err
	}
	err = db.Update(func(tx *bolt.Tx) error {
		_, err = tx.CreateBucketIfNotExists(bucketRoomStreams)
		if err != nil {
			return err
		}
		_, err = tx.CreateBucketIfNotExists(bucketRoomEventIDs)
		if err != nil {
			return err
		}
		_, err = tx.CreateBucketIfNotExists(bucketStreamPointers)
		if err != nil {
			return err
		}
		return nil
	})
	if err != nil {
		return nil, err
	}
	hm.db = db
	return hm, nil
}

func (hm *HistoryManager) Close() error {
	return hm.db.Close()
}

func (hm *HistoryManager) Get(room *rooms.Room, eventID string) (event *mautrix.Event, err error) {
	err = hm.db.View(func(tx *bolt.Tx) error {
		rid := []byte(room.ID)
		eventIDs := tx.Bucket(bucketRoomEventIDs).Bucket(rid)
		if eventIDs == nil {
			return nil
		}
		streamIndex := eventIDs.Get([]byte(eventID))
		if streamIndex == nil {
			return nil
		}
		stream := tx.Bucket(bucketRoomStreams).Bucket(rid)
		eventData := stream.Get(streamIndex)
		var umErr error
		event, umErr = unmarshalEvent(eventData)
		return umErr
	})
	return
}

func (hm *HistoryManager) Append(room *rooms.Room, events []*mautrix.Event) error {
	return hm.store(room, events, true)
}

func (hm *HistoryManager) Prepend(room *rooms.Room, events []*mautrix.Event) error {
	return hm.store(room, events, false)
}

func (hm *HistoryManager) store(room *rooms.Room, events []*mautrix.Event, append bool) error {
	hm.Lock()
	defer hm.Unlock()
	err := hm.db.Update(func(tx *bolt.Tx) error {
		streamPointers := tx.Bucket(bucketStreamPointers)
		rid := []byte(room.ID)
		stream, err := tx.Bucket(bucketRoomStreams).CreateBucketIfNotExists(rid)
		if err != nil {
			return err
		}
		eventIDs, err := tx.Bucket(bucketRoomEventIDs).CreateBucketIfNotExists(rid)
		if err != nil {
			return err
		}
		if stream.Sequence() < halfUint64 {
			// The sequence counter (i.e. the future) the part after 2^63, i.e. the second half of uint64
			// We set it to -1 because NextSequence will increment it by one.
			err = stream.SetSequence(halfUint64 - 1)
			if err != nil {
				return err
			}
		}
		if append {
			ptrStart, err := stream.NextSequence()
			if err != nil {
				return err
			}
			for i, event := range events {
				if err := put(stream, eventIDs, event, ptrStart+uint64(i)); err != nil {
					return err
				}
			}
			err = stream.SetSequence(ptrStart + uint64(len(events)) - 1)
			if err != nil {
				return err
			}
		} else {
			ptrStart, ok := hm.historyEndPtr[room]
			if !ok {
				ptrStartRaw := streamPointers.Get(rid)
				if ptrStartRaw != nil {
					ptrStart = btoi(ptrStartRaw)
				} else {
					ptrStart = halfUint64 - 1
				}
			}
			eventCount := uint64(len(events))
			for i, event := range events {
				if err := put(stream, eventIDs, event, -ptrStart-uint64(i)); err != nil {
					return err
				}
			}
			hm.historyEndPtr[room] = ptrStart + eventCount
			err := streamPointers.Put(rid, itob(ptrStart+eventCount))
			if err != nil {
				return err
			}
		}

		return nil
	})
	return err
}

func (hm *HistoryManager) Load(room *rooms.Room, num int) (events []*mautrix.Event, err error) {
	hm.Lock()
	defer hm.Unlock()
	err = hm.db.View(func(tx *bolt.Tx) error {
		rid := []byte(room.ID)
		stream := tx.Bucket(bucketRoomStreams).Bucket(rid)
		if stream == nil {
			return nil
		}
		ptrStart, ok := hm.historyLoadPtr[room]
		if !ok {
			ptrStart = stream.Sequence()
		}
		c := stream.Cursor()
		k, v := c.Seek(itob(ptrStart - uint64(num)))
		ptrStartFound := btoi(k)
		if k == nil || ptrStartFound >= ptrStart {
			return nil
		}
		hm.historyLoadPtr[room] = ptrStartFound - 1
		for ; k != nil && btoi(k) < ptrStart; k, v = c.Next() {
			event, parseError := unmarshalEvent(v)
			if parseError != nil {
				return parseError
			}
			events = append(events, event)
		}
		return nil
	})
	// Reverse array because we read/append the history in reverse order.
	i := 0
	j := len(events) - 1
	for i < j {
		events[i], events[j] = events[j], events[i]
		i++
		j--
	}
	return
}

func itob(v uint64) []byte {
	b := make([]byte, 8)
	binary.BigEndian.PutUint64(b, v)
	return b
}

func btoi(b []byte) uint64 {
	return binary.BigEndian.Uint64(b)
}

func marshalEvent(event *mautrix.Event) ([]byte, error) {
	var buf bytes.Buffer
	err := gob.NewEncoder(&buf).Encode(event)
	return buf.Bytes(), err
}

func unmarshalEvent(data []byte) (*mautrix.Event, error) {
	event := &mautrix.Event{}
	return event, gob.NewDecoder(bytes.NewReader(data)).Decode(event)
}

func put(streams, eventIDs *bolt.Bucket, event *mautrix.Event, key uint64) error {
	data, err := marshalEvent(event)
	if err != nil {
		return err
	}
	keyBytes := itob(key)
	if err = streams.Put(keyBytes, data); err != nil {
		return err
	}
	if err = eventIDs.Put([]byte(event.ID), keyBytes); err != nil {
		return err
	}
	return nil
}