forked from ProtonMail/proton-bridge
/
cache.go
116 lines (93 loc) · 2.63 KB
/
cache.go
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// Copyright (c) 2021 Proton Technologies AG
//
// This file is part of ProtonMail Bridge.
//
// ProtonMail Bridge is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// ProtonMail Bridge 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with ProtonMail Bridge. If not, see <https://www.gnu.org/licenses/>.
package store
import (
"encoding/json"
"os"
"sync"
"github.com/pkg/errors"
)
// Cache caches the last event IDs for all accounts (there should be only one instance).
type Cache struct {
// cache is map from userID => key (such as last event) => value (such as event ID).
cache map[string]map[string]string
path string
lock *sync.RWMutex
}
// NewCache constructs a new cache at the given path.
func NewCache(path string) *Cache {
return &Cache{
path: path,
lock: &sync.RWMutex{},
}
}
func (c *Cache) getEventID(userID string) string {
c.lock.Lock()
defer c.lock.Unlock()
if err := c.loadCache(); err != nil {
log.WithError(err).Warn("Problem to load store cache")
}
if c.cache == nil {
c.cache = map[string]map[string]string{}
}
if c.cache[userID] == nil {
c.cache[userID] = map[string]string{}
}
return c.cache[userID]["events"]
}
func (c *Cache) setEventID(userID, eventID string) error {
c.lock.Lock()
defer c.lock.Unlock()
if c.cache[userID] == nil {
c.cache[userID] = map[string]string{}
}
c.cache[userID]["events"] = eventID
return c.saveCache()
}
func (c *Cache) loadCache() error {
if c.cache != nil {
return nil
}
f, err := os.Open(c.path)
if err != nil {
return err
}
defer f.Close() //nolint[errcheck]
return json.NewDecoder(f).Decode(&c.cache)
}
func (c *Cache) saveCache() error {
if c.cache == nil {
return errors.New("events: cannot save cache: cache is nil")
}
f, err := os.Create(c.path)
if err != nil {
return err
}
defer f.Close() //nolint[errcheck]
return json.NewEncoder(f).Encode(c.cache)
}
func (c *Cache) clearCacheUser(userID string) error {
c.lock.Lock()
defer c.lock.Unlock()
if c.cache == nil {
log.WithField("user", userID).Warning("Cannot clear user from cache: cache is nil")
return nil
}
log.WithField("user", userID).Trace("Removing user from event loop cache")
delete(c.cache, userID)
return c.saveCache()
}