Official cwtch.im peer and server implementations. https://cwtch.im
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package v1
import (
"cwtch.im/cwtch/model"
"encoding/json"
"fmt"
"git.openprivacy.ca/openprivacy/log"
"io/ioutil"
"math"
"os"
"path"
"sync"
)
// This number is larger that the recommend chunk size of libsodium secretbox by an order of magnitude.
// Since this code is not performance-sensitive (and is unlikely to gain any significant performance benefit from
// cache-efficient chunking) this size isn’t currently a concern.
// TODO: revise and evaluate better storage options after beta”
const (
fileStorePartitions = 128
bytesPerFile = 128 * 1024
)
// streamStore is a file-backed implementation of StreamStore using an in memory buffer of ~16KB and a rotating set of files
type streamStore struct {
key [32]byte
storeDirectory string
filenameBase string
// Buffer is used just for current file to write to
messages []model.Message
bufferByteCount int
lock sync.Mutex
}
// StreamStore provides a stream like interface to encrypted storage
type StreamStore interface {
Write(message model.Message)
WriteN(messages []model.Message)
Read() []model.Message
Delete()
}
// NewStreamStore returns an initialized StreamStore ready for reading and writing
func NewStreamStore(directory string, filenameBase string, key [32]byte) (store StreamStore) {
ss := &streamStore{storeDirectory: directory, filenameBase: filenameBase, key: key}
os.Mkdir(ss.storeDirectory, 0700)
ss.initBuffer()
ss.initBufferFromStorage()
return ss
}
func (ss *streamStore) initBuffer() {
ss.messages = []model.Message{}
ss.bufferByteCount = 0
}
func (ss *streamStore) initBufferFromStorage() error {
filename := fmt.Sprintf("%s.%d", ss.filenameBase, 0)
bytes, _ := ReadEncryptedFile(ss.storeDirectory, filename, ss.key)
msgs := []model.Message{}
err := json.Unmarshal([]byte(bytes), &msgs)
if err != nil {
return err
}
for _, message := range msgs {
ss.updateBuffer(message)
}
return nil
}
func (ss *streamStore) updateBuffer(m model.Message) {
ss.messages = append(ss.messages, m)
ss.bufferByteCount += int(math.Ceil(model.MessageBaseSize*1.5)) + len(m.Message)
}
func (ss *streamStore) updateFile() error {
msgs, err := json.Marshal(ss.messages)
if err != nil {
log.Errorf("Failed to marshal group messages %v\n", err)
}
// ENCRYPT
encryptedMsgs, err := EncryptFileData(msgs, ss.key)
if err != nil {
log.Errorf("Failed to encrypt messages: %v\n", err)
return err
}
ioutil.WriteFile(path.Join(ss.storeDirectory, fmt.Sprintf("%s.%d", ss.filenameBase, 0)), encryptedMsgs, 0600)
return nil
}
func (ss *streamStore) rotateFileStore() {
os.Remove(path.Join(ss.storeDirectory, fmt.Sprintf("%s.%d", ss.filenameBase, fileStorePartitions-1)))
for i := fileStorePartitions - 2; i >= 0; i-- {
os.Rename(path.Join(ss.storeDirectory, fmt.Sprintf("%s.%d", ss.filenameBase, i)), path.Join(ss.storeDirectory, fmt.Sprintf("%s.%d", ss.filenameBase, i+1)))
}
}
// Delete deletes all the files associated with this streamStore
func (ss *streamStore) Delete() {
for i := fileStorePartitions - 1; i >= 0; i-- {
os.Remove(path.Join(ss.storeDirectory, fmt.Sprintf("%s.%d", ss.filenameBase, i)))
}
}
// Read returns all messages from the backing file (not the buffer, for writing to the current file)
func (ss *streamStore) Read() (messages []model.Message) {
ss.lock.Lock()
defer ss.lock.Unlock()
resp := []model.Message{}
for i := fileStorePartitions - 1; i >= 0; i-- {
filename := fmt.Sprintf("%s.%d", ss.filenameBase, i)
bytes, err := ReadEncryptedFile(ss.storeDirectory, filename, ss.key)
if err != nil {
continue
}
msgs := []model.Message{}
json.Unmarshal([]byte(bytes), &msgs)
resp = append(resp, msgs...)
}
return resp
}
// Write adds a GroupMessage to the store
func (ss *streamStore) Write(m model.Message) {
ss.lock.Lock()
defer ss.lock.Unlock()
ss.updateBuffer(m)
ss.updateFile()
if ss.bufferByteCount > bytesPerFile {
log.Debugf("rotating log file")
ss.rotateFileStore()
ss.initBuffer()
}
}
func (ss *streamStore) WriteN(messages []model.Message) {
ss.lock.Lock()
defer ss.lock.Unlock()
log.Infof("WriteN %v messages\n", len(messages))
i := 0
for _, m := range messages {
ss.updateBuffer(m)
i++
if ss.bufferByteCount > bytesPerFile {
ss.updateFile()
ss.rotateFileStore()
ss.initBuffer()
}
}
ss.updateFile()
}