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md_id_journal.go
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/
md_id_journal.go
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// Copyright 2016 Keybase Inc. All rights reserved.
// Use of this source code is governed by a BSD
// license that can be found in the LICENSE file.
package libkbfs
import (
"reflect"
"github.com/keybase/client/go/kbfs/ioutil"
"github.com/keybase/client/go/kbfs/kbfscodec"
"github.com/keybase/client/go/kbfs/kbfsmd"
"github.com/keybase/go-codec/codec"
"github.com/pkg/errors"
)
// An mdIDJournal wraps a diskJournal to provide a persistent list of
// MdIDs (with possible other fields in the future) with sequential
// Revisions for a single branch.
//
// Like diskJournal, this type assumes that the directory passed into
// makeMdIDJournal isn't used by anything else, and that all
// synchronization is done at a higher level.
//
// TODO: Write unit tests for this. For now, we're relying on
// md_journal.go's unit tests.
type mdIDJournal struct {
j *diskJournal
}
// An mdIDJournalEntry is an MdID and a boolean describing whether
// this entry was the result of a local squash. Make sure that new
// fields don't depend on the ID or `isLocalSquash`, as the mdJournal
// may change these when converting to a branch. Note that
// `isLocalSquash` may only be true for entries in a continuous prefix
// of the id journal; once there is one entry with `isLocalSquash =
// false`, it will be the same in all the remaining entries.
type mdIDJournalEntry struct {
ID kbfsmd.ID
// IsLocalSquash is true when this MD is the result of
// squashing some other local MDs.
IsLocalSquash bool `codec:",omitempty"`
// WKBNew is true when the writer key bundle for this MD is
// new and has to be pushed to the server. This is always
// false for MDv2.
WKBNew bool `codec:",omitempty"`
// RKBNew is true when the reader key bundle for this MD is
// new and has to be pushed to the server. This is always
// false for MDv2.
RKBNew bool `codec:",omitempty"`
codec.UnknownFieldSetHandler
}
func makeMdIDJournal(codec kbfscodec.Codec, dir string) (mdIDJournal, error) {
j, err :=
makeDiskJournal(codec, dir, reflect.TypeOf(mdIDJournalEntry{}))
if err != nil {
return mdIDJournal{}, err
}
return mdIDJournal{j}, nil
}
func ordinalToRevision(o journalOrdinal) (kbfsmd.Revision, error) {
r := kbfsmd.Revision(o)
if r < kbfsmd.RevisionInitial {
return kbfsmd.RevisionUninitialized, errors.Errorf(
"Cannot convert ordinal %s to a kbfsmd.Revision", o)
}
return r, nil
}
func revisionToOrdinal(r kbfsmd.Revision) (journalOrdinal, error) {
if r < kbfsmd.RevisionInitial {
return journalOrdinal(0), errors.Errorf(
"Cannot convert revision %s to an ordinal", r)
}
return journalOrdinal(r), nil
}
// TODO: Consider caching the values returned by the read functions
// below in memory.
func (j mdIDJournal) readEarliestRevision() (kbfsmd.Revision, error) {
o, err := j.j.readEarliestOrdinal()
if ioutil.IsNotExist(err) {
return kbfsmd.RevisionUninitialized, nil
} else if err != nil {
return kbfsmd.RevisionUninitialized, err
}
return ordinalToRevision(o)
}
func (j mdIDJournal) readLatestRevision() (kbfsmd.Revision, error) {
o, err := j.j.readLatestOrdinal()
if ioutil.IsNotExist(err) {
return kbfsmd.RevisionUninitialized, nil
} else if err != nil {
return kbfsmd.RevisionUninitialized, err
}
return ordinalToRevision(o)
}
func (j mdIDJournal) writeLatestRevision(r kbfsmd.Revision) error {
o, err := revisionToOrdinal(r)
if err != nil {
return err
}
return j.j.writeLatestOrdinal(o)
}
func (j mdIDJournal) readJournalEntry(r kbfsmd.Revision) (
mdIDJournalEntry, error) {
o, err := revisionToOrdinal(r)
if err != nil {
return mdIDJournalEntry{}, err
}
e, err := j.j.readJournalEntry(o)
if err != nil {
return mdIDJournalEntry{}, err
}
return e.(mdIDJournalEntry), nil
}
// All functions below are public functions.
func (j mdIDJournal) length() uint64 {
return j.j.length()
}
func (j mdIDJournal) end() (kbfsmd.Revision, error) {
last, err := j.readLatestRevision()
if err != nil {
return kbfsmd.RevisionUninitialized, err
}
if last == kbfsmd.RevisionUninitialized {
return kbfsmd.RevisionUninitialized, nil
}
return last + 1, nil
}
func (j mdIDJournal) getEarliestEntry() (
entry mdIDJournalEntry, exists bool, err error) {
earliestRevision, err := j.readEarliestRevision()
if err != nil {
return mdIDJournalEntry{}, false, err
} else if earliestRevision == kbfsmd.RevisionUninitialized {
return mdIDJournalEntry{}, false, nil
}
entry, err = j.readJournalEntry(earliestRevision)
if err != nil {
return mdIDJournalEntry{}, false, err
}
return entry, true, err
}
func (j mdIDJournal) getLatestEntry() (
entry mdIDJournalEntry, exists bool, err error) {
latestRevision, err := j.readLatestRevision()
if err != nil {
return mdIDJournalEntry{}, false, err
} else if latestRevision == kbfsmd.RevisionUninitialized {
return mdIDJournalEntry{}, false, nil
}
entry, err = j.readJournalEntry(latestRevision)
if err != nil {
return mdIDJournalEntry{}, false, err
}
return entry, true, err
}
func (j mdIDJournal) getEntryRange(start, stop kbfsmd.Revision) (
kbfsmd.Revision, []mdIDJournalEntry, error) {
earliestRevision, err := j.readEarliestRevision()
if err != nil {
return kbfsmd.RevisionUninitialized, nil, err
} else if earliestRevision == kbfsmd.RevisionUninitialized {
return kbfsmd.RevisionUninitialized, nil, nil
}
latestRevision, err := j.readLatestRevision()
if err != nil {
return kbfsmd.RevisionUninitialized, nil, err
} else if latestRevision == kbfsmd.RevisionUninitialized {
return kbfsmd.RevisionUninitialized, nil, nil
}
if start < earliestRevision {
start = earliestRevision
}
if stop > latestRevision {
stop = latestRevision
}
if stop < start {
return kbfsmd.RevisionUninitialized, nil, nil
}
var entries []mdIDJournalEntry
for i := start; i <= stop; i++ {
entry, err := j.readJournalEntry(i)
if err != nil {
return kbfsmd.RevisionUninitialized, nil, err
}
entries = append(entries, entry)
}
return start, entries, nil
}
func (j mdIDJournal) replaceHead(entry mdIDJournalEntry) error {
o, err := j.j.readLatestOrdinal()
if err != nil {
return err
}
return j.j.writeJournalEntry(o, entry)
}
func (j mdIDJournal) append(r kbfsmd.Revision, entry mdIDJournalEntry) error {
o, err := revisionToOrdinal(r)
if err != nil {
return err
}
_, err = j.j.appendJournalEntry(&o, entry)
return err
}
func (j mdIDJournal) removeEarliest() (empty bool, err error) {
return j.j.removeEarliest()
}
func (j mdIDJournal) clear() error {
return j.j.clear()
}
func (j mdIDJournal) clearFrom(revision kbfsmd.Revision) error {
earliestRevision, err := j.readEarliestRevision()
if err != nil {
return err
}
if revision < earliestRevision {
return errors.Errorf("Cannot call clearFrom with revision %s < %s",
revision, earliestRevision)
}
if revision == earliestRevision {
return j.clear()
}
latestRevision, err := j.readLatestRevision()
if err != nil {
return err
}
err = j.writeLatestRevision(revision - 1)
if err != nil {
return err
}
o, err := revisionToOrdinal(revision)
if err != nil {
return err
}
latestOrdinal, err := revisionToOrdinal(latestRevision)
if err != nil {
return err
}
for ; o <= latestOrdinal; o++ {
p := j.j.journalEntryPath(o)
err = ioutil.Remove(p)
if err != nil {
return err
}
}
return nil
}
// Note that since diskJournal.move takes a pointer receiver, so must
// this.
func (j *mdIDJournal) move(newDir string) (oldDir string, err error) {
return j.j.move(newDir)
}