notmuch: avoid stale DBs
Opening a notmuch DB gives you a snapshot of the stage at that specific time. Prior to this, we only reopened the DB upon writing. However, if say a mail sync program like offlineimap is fetching new mail, we would never pick it up. This commit caches a db for a while, so that we don't generate too much overhead and does a reconnect cycle after that. I hardcoded a value as I don't think that having an option would be beneficial. Any write operation (meaning reading mail) anyhow flushes the DB by necessity. (we need to close to commit tag changes, which changing the read state is)
This commit is contained in:
Reto Brunner
Drew DeVault
parent
72f55b857b
commit
3e7e236f50
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@ -5,15 +5,19 @@ package lib
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import (
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"fmt"
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"log"
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"time"
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notmuch "github.com/zenhack/go.notmuch"
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)
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const MAX_DB_AGE time.Duration = 10 * time.Second
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type DB struct {
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path string
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excludedTags []string
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ro *notmuch.DB
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logger *log.Logger
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lastOpenTime time.Time
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db *notmuch.DB
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}
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func NewDB(path string, excludedTags []string,
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@ -27,58 +31,79 @@ func NewDB(path string, excludedTags []string,
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}
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func (db *DB) Connect() error {
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return db.connectRO()
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// used as sanity check upon initial connect
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err := db.connect(false)
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return err
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}
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// connectRW returns a writable notmuch DB, which needs to be closed to commit
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// the changes and to release the DB lock
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func (db *DB) connectRW() (*notmuch.DB, error) {
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rw, err := notmuch.Open(db.path, notmuch.DBReadWrite)
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if err != nil {
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return nil, fmt.Errorf("could not connect to notmuch db: %v", err)
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func (db *DB) close() error {
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if db.db == nil {
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return nil
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}
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return rw, err
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err := db.db.Close()
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db.db = nil
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return err
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}
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// connectRO connects a RO db to the worker
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func (db *DB) connectRO() error {
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if db.ro != nil {
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if err := db.ro.Close(); err != nil {
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db.logger.Printf("connectRO: could not close the old db: %v", err)
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}
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func (db *DB) connect(writable bool) error {
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var mode notmuch.DBMode = notmuch.DBReadOnly
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if writable {
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mode = notmuch.DBReadWrite
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}
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var err error
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db.ro, err = notmuch.Open(db.path, notmuch.DBReadOnly)
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db.db, err = notmuch.Open(db.path, mode)
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if err != nil {
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return fmt.Errorf("could not connect to notmuch db: %v", err)
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}
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db.lastOpenTime = time.Now()
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return nil
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}
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//withConnection calls callback on the DB object, cleaning up upon return.
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//the error returned is from the connection attempt, if not successful,
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//or from the callback otherwise.
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func (db *DB) withConnection(writable bool, cb func(*notmuch.DB) error) error {
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too_old := time.Now().After(db.lastOpenTime.Add(MAX_DB_AGE))
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if db.db == nil || writable || too_old {
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if cerr := db.close(); cerr != nil {
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db.logger.Printf("failed to close the notmuch db: %v", cerr)
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}
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err := db.connect(writable)
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if err != nil {
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return err
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}
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}
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err := cb(db.db)
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if writable {
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// we need to close to commit the changes, else we block others
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if cerr := db.close(); cerr != nil {
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db.logger.Printf("failed to close the notmuch db: %v", cerr)
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}
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}
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return err
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}
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// ListTags lists all known tags
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func (db *DB) ListTags() ([]string, error) {
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if db.ro == nil {
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return nil, fmt.Errorf("not connected to the notmuch db")
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}
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tags, err := db.ro.Tags()
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if err != nil {
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return nil, err
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}
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var result []string
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err := db.withConnection(false, func(ndb *notmuch.DB) error {
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tags, err := ndb.Tags()
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if err != nil {
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return err
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}
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var tag *notmuch.Tag
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for tags.Next(&tag) {
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result = append(result, tag.Value)
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}
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return result, nil
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return nil
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})
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return result, err
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}
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//getQuery returns a query based on the provided query string.
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//It also configures the query as specified on the worker
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func (db *DB) newQuery(query string) (*notmuch.Query, error) {
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if db.ro == nil {
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return nil, fmt.Errorf("not connected to the notmuch db")
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}
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q := db.ro.NewQuery(query)
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func (db *DB) newQuery(ndb *notmuch.DB, query string) (*notmuch.Query, error) {
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q := ndb.NewQuery(query)
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q.SetExcludeScheme(notmuch.EXCLUDE_TRUE)
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q.SetSortScheme(notmuch.SORT_OLDEST_FIRST)
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for _, t := range db.excludedTags {
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@ -91,23 +116,23 @@ func (db *DB) newQuery(query string) (*notmuch.Query, error) {
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}
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func (db *DB) MsgIDsFromQuery(q string) ([]string, error) {
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if db.ro == nil {
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return nil, fmt.Errorf("not connected to the notmuch db")
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}
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query, err := db.newQuery(q)
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var msgIDs []string
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err := db.withConnection(false, func(ndb *notmuch.DB) error {
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query, err := db.newQuery(ndb, q)
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if err != nil {
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return nil, err
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return err
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}
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msgs, err := query.Messages()
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if err != nil {
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return nil, err
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return err
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}
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var msg *notmuch.Message
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var msgIDs []string
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for msgs.Next(&msg) {
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msgIDs = append(msgIDs, msg.ID())
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}
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return msgIDs, nil
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return nil
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})
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return msgIDs, err
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}
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type MessageCount struct {
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@ -116,60 +141,67 @@ type MessageCount struct {
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}
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func (db *DB) QueryCountMessages(q string) (MessageCount, error) {
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query, err := db.newQuery(q)
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var (
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exists int
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unread int
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)
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err := db.withConnection(false, func(ndb *notmuch.DB) error {
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query, err := db.newQuery(ndb, q)
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if err != nil {
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return MessageCount{}, err
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return err
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}
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exists := query.CountMessages()
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exists = query.CountMessages()
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query.Close()
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uq, err := db.newQuery(fmt.Sprintf("(%v) and (tag:unread)", q))
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uq, err := db.newQuery(ndb, fmt.Sprintf("(%v) and (tag:unread)", q))
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if err != nil {
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return MessageCount{}, err
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return err
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}
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defer uq.Close()
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unread := uq.CountMessages()
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unread = uq.CountMessages()
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return nil
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})
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return MessageCount{
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Exists: exists,
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Unread: unread,
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}, nil
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}, err
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}
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func (db *DB) MsgFilename(key string) (string, error) {
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msg, err := db.ro.FindMessage(key)
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var filename string
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err := db.withConnection(false, func(ndb *notmuch.DB) error {
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msg, err := ndb.FindMessage(key)
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if err != nil {
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return "", err
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return err
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}
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defer msg.Close()
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return msg.Filename(), nil
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filename = msg.Filename()
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return nil
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})
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return filename, err
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}
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func (db *DB) MsgTags(key string) ([]string, error) {
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msg, err := db.ro.FindMessage(key)
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var tags []string
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err := db.withConnection(false, func(ndb *notmuch.DB) error {
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msg, err := ndb.FindMessage(key)
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if err != nil {
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return nil, err
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return err
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}
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defer msg.Close()
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ts := msg.Tags()
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var tags []string
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var tag *notmuch.Tag
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for ts.Next(&tag) {
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tags = append(tags, tag.Value)
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}
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return tags, nil
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return nil
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})
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return tags, err
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}
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func (db *DB) msgModify(key string,
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cb func(*notmuch.Message) error) error {
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defer db.connectRO()
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db.ro.Close()
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rw, err := db.connectRW()
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if err != nil {
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return err
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}
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defer rw.Close()
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msg, err := rw.FindMessage(key)
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err := db.withConnection(true, func(ndb *notmuch.DB) error {
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msg, err := ndb.FindMessage(key)
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if err != nil {
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return err
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}
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@ -181,6 +213,8 @@ func (db *DB) msgModify(key string,
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db.logger.Printf("could not sync maildir flags: %v", err)
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}
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return nil
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})
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return err
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}
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func (db *DB) MsgModifyTags(key string, add, remove []string) error {
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