syncthing/files/set.go

329 lines
6.5 KiB
Go

// Package files provides a set type to track local/remote files with newness checks.
package files
import (
"crypto/md5"
"sync"
"github.com/calmh/syncthing/cid"
"github.com/calmh/syncthing/lamport"
"github.com/calmh/syncthing/protocol"
"github.com/calmh/syncthing/scanner"
)
type key struct {
Name string
Version uint64
Modified int64
Hash [md5.Size]byte
}
type fileRecord struct {
Usage int
File scanner.File
}
type bitset uint64
func keyFor(f scanner.File) key {
h := md5.New()
for _, b := range f.Blocks {
h.Write(b.Hash)
}
return key{
Name: f.Name,
Version: f.Version,
Modified: f.Modified,
Hash: md5.Sum(nil),
}
}
func (a key) newerThan(b key) bool {
if a.Version != b.Version {
return a.Version > b.Version
}
if a.Modified != b.Modified {
return a.Modified > b.Modified
}
for i := 0; i < md5.Size; i++ {
if a.Hash[i] != b.Hash[i] {
return a.Hash[i] > b.Hash[i]
}
}
return false
}
type Set struct {
sync.Mutex
files map[key]fileRecord
remoteKey [64]map[string]key
changes [64]uint64
globalAvailability map[string]bitset
globalKey map[string]key
}
func NewSet() *Set {
var m = Set{
files: make(map[key]fileRecord),
globalAvailability: make(map[string]bitset),
globalKey: make(map[string]key),
}
return &m
}
func (m *Set) Replace(id uint, fs []scanner.File) {
if debug {
dlog.Printf("Replace(%d, [%d])", id, len(fs))
}
if id > 63 {
panic("Connection ID must be in the range 0 - 63 inclusive")
}
m.Lock()
if len(fs) == 0 || !m.equals(id, fs) {
m.changes[id]++
m.replace(id, fs)
}
m.Unlock()
}
func (m *Set) ReplaceWithDelete(id uint, fs []scanner.File) {
if debug {
dlog.Printf("ReplaceWithDelete(%d, [%d])", id, len(fs))
}
if id > 63 {
panic("Connection ID must be in the range 0 - 63 inclusive")
}
m.Lock()
if len(fs) == 0 || !m.equals(id, fs) {
m.changes[id]++
var nf = make(map[string]key, len(fs))
for _, f := range fs {
nf[f.Name] = keyFor(f)
}
// For previously existing files not in the list, add them to the list
// with the relevant delete flags etc set. Previously existing files
// with the delete bit already set are not modified.
for _, ck := range m.remoteKey[cid.LocalID] {
if _, ok := nf[ck.Name]; !ok {
cf := m.files[ck].File
if cf.Flags&protocol.FlagDeleted != protocol.FlagDeleted {
cf.Flags |= protocol.FlagDeleted
cf.Blocks = nil
cf.Size = 0
cf.Version = lamport.Default.Tick(cf.Version)
}
fs = append(fs, cf)
if debug {
dlog.Println("deleted:", ck.Name)
}
}
}
m.replace(id, fs)
}
m.Unlock()
}
func (m *Set) Update(id uint, fs []scanner.File) {
if debug {
dlog.Printf("Update(%d, [%d])", id, len(fs))
}
m.Lock()
m.update(id, fs)
m.changes[id]++
m.Unlock()
}
func (m *Set) Need(id uint) []scanner.File {
if debug {
dlog.Printf("Need(%d)", id)
}
var fs []scanner.File
m.Lock()
rkID := m.remoteKey[id]
for name, gk := range m.globalKey {
if gk.newerThan(rkID[name]) {
if m.files[gk].File.Flags&protocol.FlagDirectory == 0 || // Regular file
m.files[gk].File.Flags&(protocol.FlagDirectory|protocol.FlagDeleted) == protocol.FlagDirectory { // Non-deleted directory
fs = append(fs, m.files[gk].File)
}
}
}
m.Unlock()
return fs
}
func (m *Set) Have(id uint) []scanner.File {
if debug {
dlog.Printf("Have(%d)", id)
}
var fs []scanner.File
m.Lock()
for _, rk := range m.remoteKey[id] {
fs = append(fs, m.files[rk].File)
}
m.Unlock()
return fs
}
func (m *Set) Global() []scanner.File {
if debug {
dlog.Printf("Global()")
}
var fs []scanner.File
m.Lock()
for _, rk := range m.globalKey {
fs = append(fs, m.files[rk].File)
}
m.Unlock()
return fs
}
func (m *Set) Get(id uint, file string) scanner.File {
m.Lock()
defer m.Unlock()
if debug {
dlog.Printf("Get(%d, %q)", id, file)
}
return m.files[m.remoteKey[id][file]].File
}
func (m *Set) GetGlobal(file string) scanner.File {
m.Lock()
defer m.Unlock()
if debug {
dlog.Printf("GetGlobal(%q)", file)
}
return m.files[m.globalKey[file]].File
}
func (m *Set) Availability(name string) bitset {
m.Lock()
defer m.Unlock()
av := m.globalAvailability[name]
if debug {
dlog.Printf("Availability(%q) = %0x", name, av)
}
return av
}
func (m *Set) Changes(id uint) uint64 {
m.Lock()
defer m.Unlock()
if debug {
dlog.Printf("Changes(%d)", id)
}
return m.changes[id]
}
func (m *Set) equals(id uint, fs []scanner.File) bool {
curWithoutDeleted := make(map[string]key)
for _, k := range m.remoteKey[id] {
f := m.files[k].File
if f.Flags&protocol.FlagDeleted == 0 {
curWithoutDeleted[f.Name] = k
}
}
if len(curWithoutDeleted) != len(fs) {
return false
}
for _, f := range fs {
if curWithoutDeleted[f.Name] != keyFor(f) {
return false
}
}
return true
}
func (m *Set) update(cid uint, fs []scanner.File) {
remFiles := m.remoteKey[cid]
for _, f := range fs {
n := f.Name
fk := keyFor(f)
if ck, ok := remFiles[n]; ok && ck == fk {
// The remote already has exactly this file, skip it
continue
}
remFiles[n] = fk
// Keep the block list or increment the usage
if br, ok := m.files[fk]; !ok {
m.files[fk] = fileRecord{
Usage: 1,
File: f,
}
} else {
br.Usage++
m.files[fk] = br
}
// Update global view
gk, ok := m.globalKey[n]
switch {
case ok && fk == gk:
av := m.globalAvailability[n]
av |= 1 << cid
m.globalAvailability[n] = av
case fk.newerThan(gk):
m.globalKey[n] = fk
m.globalAvailability[n] = 1 << cid
}
}
}
func (m *Set) replace(cid uint, fs []scanner.File) {
// Decrement usage for all files belonging to this remote, and remove
// those that are no longer needed.
for _, fk := range m.remoteKey[cid] {
br, ok := m.files[fk]
switch {
case ok && br.Usage == 1:
delete(m.files, fk)
case ok && br.Usage > 1:
br.Usage--
m.files[fk] = br
}
}
// Clear existing remote remoteKey
m.remoteKey[cid] = make(map[string]key)
// Recalculate global based on all remaining remoteKey
for n := range m.globalKey {
var nk key // newest key
var na bitset // newest availability
for i, rem := range m.remoteKey {
if rk, ok := rem[n]; ok {
switch {
case rk == nk:
na |= 1 << uint(i)
case rk.newerThan(nk):
nk = rk
na = 1 << uint(i)
}
}
}
if na != 0 {
// Someone had the file
m.globalKey[n] = nk
m.globalAvailability[n] = na
} else {
// Noone had the file
delete(m.globalKey, n)
delete(m.globalAvailability, n)
}
}
// Add new remote remoteKey to the mix
m.update(cid, fs)
}