func New(path string) (s *Storage, err error) {
kyoto := cabinet.New()
if err = kyoto.Open(path, cabinet.KCOWRITER|cabinet.KCOCREATE); err != nil {
return
}
s = &Storage{
kyoto: kyoto,
counters: make(map[string]*counter),
}
s.loadState()
go s.keepStatePersisted()
return
}
func OpenKyotoDB(filename string, writemode bool) (KyotoDB, error) {
db := KyotoDB{}
db.kcdb = cabinet.New()
mode := cabinet.KCOREADER
if writemode {
mode = cabinet.KCOWRITER | cabinet.KCOCREATE
}
err := db.kcdb.Open(filename, mode)
if err != nil {
db.kcdb.Del()
db.kcdb = nil
// errors returned by KC are pretty sparse ;-(
return db, fmt.Errorf("could not open %s: %s", filename, err)
}
err = db.checkVersion(
filename, writemode, CURRENT_VERSION, MIN_VERSION, MAX_VERSION)
if err != nil {
db.Close()
return db, err
}
return db, nil
}
func Test_KyotoDB_checkVersion(t *testing.T) {
cleanup := testutils.Chtemp()
defer cleanup()
// brand-new empty DB with no version number in it
db := KyotoDB{}
db.kcdb = cabinet.New()
filename := "test.kch"
err := db.kcdb.Open(filename, cabinet.KCOWRITER|cabinet.KCOCREATE)
if err != nil {
t.Fatal(err)
}
// checkVersion() on an empty DB in read-only mode fails, because
// it can neither read nor write the version number
err = db.checkVersion(filename, false, 0, 0, 0)
expect := "database test.kch has no version number"
if err == nil || err.Error() != expect {
t.Errorf("expected error %s, but got %v", expect, err)
}
// in write mode it's OK, and sets the version number in the file
err = db.checkVersion(filename, true, 513, 513, 513)
assert.Nil(t, err)
versionkey := makekey(PREFIX_META, "version")
val, err := db.kcdb.Get(versionkey)
assert.Nil(t, err)
assert.Equal(t, "\x00\x00\x02\x01", string(val))
// once the version number is in the file, write mode doesn't
// matter -- now it's down to comparing with the supported range
// of versions
err = db.checkVersion(filename, false, 513, 134, 231)
expect = "database test.kch is from the future (database version = 513, but max supported version = 231)"
if err == nil || err.Error() != expect {
t.Errorf("expected error\n%s\nbut got\n%v", expect, err)
}
err = db.checkVersion(filename, false, 513, 534, 546)
expect = "database test.kch is too old (database version = 513, but min supported version = 534)"
if err == nil || err.Error() != expect {
t.Errorf("expected error\n%s\nbut got\n%v", expect, err)
}
err = db.checkVersion(filename, false, 513, 512, 514)
assert.Nil(t, err)
err = db.checkVersion(filename, false, 513, 513, 513)
assert.Nil(t, err)
err = db.checkVersion(filename, false, 513, 512, 513)
assert.Nil(t, err)
err = db.checkVersion(filename, false, 513, 513, 514)
assert.Nil(t, err)
// corrupt version number
err = db.kcdb.Set(versionkey, []byte{0, 0x43, 0})
assert.Nil(t, err)
err = db.checkVersion(filename, false, 513, 513, 513)
expect = "database test.kch: unable to decode version number (004300)"
if err == nil || err.Error() != expect {
t.Errorf("expected error\n%s\nbut got\n%v", expect, err)
}
}