summaryrefslogtreecommitdiff
path: root/worker/imap/cache.go
blob: ecbedd8936c4995ba418272fc149448341f33eca (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
package imap

import (
	"bufio"
	"bytes"
	"encoding/gob"
	"fmt"
	"os"
	"path"
	"time"

	"git.sr.ht/~rjarry/aerc/models"
	"git.sr.ht/~rjarry/aerc/worker/types"
	"github.com/emersion/go-message"
	"github.com/emersion/go-message/mail"
	"github.com/emersion/go-message/textproto"
	"github.com/mitchellh/go-homedir"
	"github.com/syndtr/goleveldb/leveldb"
)

type CachedHeader struct {
	BodyStructure models.BodyStructure
	Envelope      models.Envelope
	InternalDate  time.Time
	Uid           uint32
	Header        []byte
	Created       time.Time
}

// initCacheDb opens (or creates) the database for the cache. One database is
// created per account
func (w *IMAPWorker) initCacheDb(acct string) {
	cd, err := cacheDir()
	if err != nil {
		w.cache = nil
		w.worker.Logger.Panicf("cache: unable to find cache directory: %v", err)
		return
	}
	p := path.Join(cd, acct)
	db, err := leveldb.OpenFile(p, nil)
	if err != nil {
		w.cache = nil
		w.worker.Logger.Printf("cache: error opening cache db: %v", err)
		return
	}
	w.cache = db
	w.worker.Logger.Printf("cache: cache db opened: %s", p)
	if w.config.cacheMaxAge.Hours() > 0 {
		go w.cleanCache()
	}
}

func (w *IMAPWorker) cacheHeader(mi *models.MessageInfo) {
	uv := fmt.Sprintf("%d", w.selected.UidValidity)
	uid := fmt.Sprintf("%d", mi.Uid)
	w.worker.Logger.Printf("cache: caching header for message %s.%s", uv, uid)
	hdr := bytes.NewBuffer(nil)
	err := textproto.WriteHeader(hdr, mi.RFC822Headers.Header.Header)
	if err != nil {
		w.worker.Logger.Printf("cache: error writing header %s.%s: %v", uv, uid, err)
		return
	}
	h := &CachedHeader{
		BodyStructure: *mi.BodyStructure,
		Envelope:      *mi.Envelope,
		InternalDate:  mi.InternalDate,
		Uid:           mi.Uid,
		Header:        hdr.Bytes(),
		Created:       time.Now(),
	}
	data := bytes.NewBuffer(nil)
	enc := gob.NewEncoder(data)
	err = enc.Encode(h)
	if err != nil {
		w.worker.Logger.Printf("cache: error encoding message %s.%s: %v", uv, uid, err)
		return
	}
	err = w.cache.Put([]byte("header."+uv+"."+uid), data.Bytes(), nil)
	if err != nil {
		w.worker.Logger.Printf("cache: error writing header to database for message %s.%s: %v", uv, uid, err)
		return
	}
}

func (w *IMAPWorker) getCachedHeaders(msg *types.FetchMessageHeaders) []uint32 {
	w.worker.Logger.Println("Retrieving headers from cache")
	var need, found []uint32
	uv := fmt.Sprintf("%d", w.selected.UidValidity)
	for _, uid := range msg.Uids {
		u := fmt.Sprintf("%d", uid)
		data, err := w.cache.Get([]byte("header."+uv+"."+u), nil)
		if err != nil {
			need = append(need, uid)
			continue
		}
		ch := &CachedHeader{}
		dec := gob.NewDecoder(bytes.NewReader(data))
		err = dec.Decode(ch)
		if err != nil {
			w.worker.Logger.Printf("cache: error decoding cached header %s.%s: %v", uv, u, err)
			need = append(need, uid)
			continue
		}
		hr := bytes.NewReader(ch.Header)
		textprotoHeader, err := textproto.ReadHeader(bufio.NewReader(hr))
		if err != nil {
			w.worker.Logger.Printf("cache: error reading cached header %s.%s: %v", uv, u, err)
			need = append(need, uid)
			continue
		}

		hdr := &mail.Header{Header: message.Header{Header: textprotoHeader}}
		mi := &models.MessageInfo{
			BodyStructure: &ch.BodyStructure,
			Envelope:      &ch.Envelope,
			Flags:         []models.Flag{models.SeenFlag}, // Always return a SEEN flag
			Uid:           ch.Uid,
			RFC822Headers: hdr,
		}
		found = append(found, uid)
		w.worker.Logger.Printf("cache: located cached header %s.%s", uv, u)
		w.worker.PostMessage(&types.MessageInfo{
			Message: types.RespondTo(msg),
			Info:    mi,
		}, nil)
	}
	if len(found) > 0 {
		w.worker.PostAction(&types.FetchMessageFlags{
			Uids: found,
		}, nil)
	}
	return need
}

func cacheDir() (string, error) {
	dir, err := os.UserCacheDir()
	if err != nil {
		dir, err = homedir.Expand("~/.cache")
		if err != nil {
			return "", err
		}
	}
	return path.Join(dir, "aerc"), nil
}

// cleanCache removes stale entries from the selected mailbox cachedb
func (w *IMAPWorker) cleanCache() {
	start := time.Now()
	var scanned, removed int
	iter := w.cache.NewIterator(nil, nil)
	for iter.Next() {
		data := iter.Value()
		ch := &CachedHeader{}
		dec := gob.NewDecoder(bytes.NewReader(data))
		err := dec.Decode(ch)
		if err != nil {
			w.worker.Logger.Printf("cache: error cleaning database %d: %v", w.selected.UidValidity, err)
			continue
		}
		exp := ch.Created.Add(w.config.cacheMaxAge)
		if exp.Before(time.Now()) {
			err = w.cache.Delete(iter.Key(), nil)
			if err != nil {
				w.worker.Logger.Printf("cache: error cleaning database %d: %v", w.selected.UidValidity, err)
				continue
			}
			removed = removed + 1
		}
		scanned = scanned + 1
	}
	iter.Release()
	elapsed := time.Since(start)
	w.worker.Logger.Printf("cache: cleaned cache, removed %d of %d entries in %f seconds", removed, scanned, elapsed.Seconds())
}