mirror of
https://github.com/ProtonMail/proton-bridge.git
synced 2025-12-18 08:06:59 +00:00
142 lines
3.4 KiB
Go
142 lines
3.4 KiB
Go
// Copyright (c) 2022 Proton Technologies AG
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//
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// This file is part of ProtonMail Bridge.
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//
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// ProtonMail Bridge is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// ProtonMail Bridge is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with ProtonMail Bridge. If not, see <https://www.gnu.org/licenses/>.
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package cache
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import (
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"errors"
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"sync"
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)
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type inMemoryCache struct {
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lock sync.RWMutex
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data map[string]map[string][]byte
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size, limit int
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}
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// NewInMemoryCache creates a new in memory cache which stores up to the given
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// number of bytes of cached data.
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// NOTE(GODT-1158): Make this threadsafe.
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func NewInMemoryCache(limit int) Cache {
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return &inMemoryCache{
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data: make(map[string]map[string][]byte),
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limit: limit,
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}
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}
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func (c *inMemoryCache) Unlock(userID string, passphrase []byte) error {
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c.data[userID] = make(map[string][]byte)
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return nil
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}
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func (c *inMemoryCache) Lock(userID string) {
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c.lock.Lock()
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defer c.lock.Unlock()
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for _, message := range c.data[userID] {
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c.size -= len(message)
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}
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delete(c.data, userID)
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}
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func (c *inMemoryCache) Delete(userID string) error {
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c.Lock(userID)
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return nil
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}
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// Has returns whether the given message exists in the cache.
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func (c *inMemoryCache) Has(userID, messageID string) bool {
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c.lock.RLock()
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defer c.lock.RUnlock()
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if !c.isUserUnlocked(userID) {
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// This might look counter intuitive but in order to be able to test
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// "re-unlocking" mechanism we need to return true here.
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//
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// The situation is the same as it would happen for onDiskCache with
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// locked user. Later during `Get` cache would return proper error
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// `ErrCacheNeedsUnlock`. It is expected that store would then try to
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// re-unlock.
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//
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// In order to do proper behaviour we should implement
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// encryption for inMemoryCache.
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return true
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}
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_, ok := c.data[userID][messageID]
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return ok
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}
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func (c *inMemoryCache) Get(userID, messageID string) ([]byte, error) {
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c.lock.RLock()
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defer c.lock.RUnlock()
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if !c.isUserUnlocked(userID) {
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return nil, ErrCacheNeedsUnlock
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}
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literal, ok := c.data[userID][messageID]
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if !ok {
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return nil, errors.New("no such message in cache")
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}
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return literal, nil
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}
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func (c *inMemoryCache) isUserUnlocked(userID string) bool {
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_, ok := c.data[userID]
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return ok
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}
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// Set saves the message literal to memory for further usage.
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//
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// NOTE(GODT-1158, GODT-1488): Once memory limit is reached we should do proper
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// rotation based on usage frequency.
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func (c *inMemoryCache) Set(userID, messageID string, literal []byte) error {
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c.lock.Lock()
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defer c.lock.Unlock()
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if !c.isUserUnlocked(userID) {
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return ErrCacheNeedsUnlock
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}
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if c.size+len(literal) > c.limit {
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return nil
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}
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c.size += len(literal)
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c.data[userID][messageID] = literal
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return nil
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}
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func (c *inMemoryCache) Rem(userID, messageID string) error {
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c.lock.Lock()
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defer c.lock.Unlock()
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if !c.isUserUnlocked(userID) {
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return nil
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}
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c.size -= len(c.data[userID][messageID])
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delete(c.data[userID], messageID)
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return nil
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}
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