/
asyncdb_iter.go
224 lines (194 loc) · 4.2 KB
/
asyncdb_iter.go
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package mpt
import (
"bytes"
"sort"
"strings"
"sync"
"sync/atomic"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/tendermint/go-amino"
)
var iterMapPool = &sync.Pool{
New: func() interface{} {
return make(map[string]int)
},
}
func (store *AsyncKeyValueStore) NewIterator(prefix []byte, start []byte) ethdb.Iterator {
atomic.AddInt64(&store.iterNum, 1)
if atomic.LoadInt64(&store.waitCommit) == 0 {
return store.KeyValueStore.NewIterator(prefix, start)
}
var (
pr = string(prefix)
st = string(append(prefix, start...))
count int
)
store.mtx.RLock()
defer store.mtx.RUnlock()
curPtr := store.getPreCommitPtr()
for curPtr.Next() != nil {
curPtr = curPtr.Next()
switch op := curPtr.Value.(*commitTask).op.(type) {
case *singleOp:
count++
case multiOp:
count += len(op)
}
}
var (
ops = make([]singleOp, 0, count)
)
if atomic.LoadInt64(&store.waitCommit) == 0 {
return store.KeyValueStore.NewIterator(prefix, start)
}
var m = iterMapPool.Get().(map[string]int)
defer iterMapPool.Put(m)
for k := range m {
delete(m, k)
}
var singleOpHandler = func(op *singleOp, pr, st string, m map[string]int, ops *[]singleOp) {
strKey := amino.BytesToStr(op.key)
if !strings.HasPrefix(strKey, pr) {
return
}
if strKey >= st {
if index, ok := m[strKey]; ok {
(*ops)[index] = *op
} else {
*ops = append(*ops, *op)
m[strKey] = len(*ops) - 1
}
}
}
// Collect the keys from the memory database corresponding to the given prefix
// and start
curPtr = store.getPreCommitPtr()
for curPtr.Next() != nil {
curPtr = curPtr.Next()
switch op := curPtr.Value.(*commitTask).op.(type) {
case *singleOp:
singleOpHandler(op, pr, st, m, &ops)
case multiOp:
for _, o := range op {
singleOpHandler(&o, pr, st, m, &ops)
if atomic.LoadInt64(&store.waitCommit) == 0 {
return store.KeyValueStore.NewIterator(prefix, start)
}
}
}
if atomic.LoadInt64(&store.waitCommit) == 0 {
return store.KeyValueStore.NewIterator(prefix, start)
}
}
dbIter := store.KeyValueStore.NewIterator(prefix, start)
if len(ops) == 0 {
return dbIter
}
// Sort the items and retrieve the associated values
sort.Slice(ops, func(i, j int) bool {
return bytes.Compare(ops[i].key, ops[j].key) == -1
})
return &asyncdbIterator{
dbIter: dbIter,
ops: ops,
memMoveNext: true,
dbMoveNext: dbIter.Next(),
dbKey: dbIter.Key(),
}
}
type asyncdbIterator struct {
dbIter ethdb.Iterator
ops []singleOp
dbKey []byte
key []byte
value []byte
dbMoveNext bool
memMoveNext bool
moveMemOrDb byte // 0 for mem, 1 for db, 2 for both
init bool
}
func (a *asyncdbIterator) Next() bool {
if len(a.ops) == 0 {
return a.dbIter.Next()
}
if !a.init {
a.init = true
} else {
if a.moveMemOrDb == 0 {
a.memMoveNext = a.memNext()
} else if a.moveMemOrDb == 1 {
a.dbMoveNext = a.dbIter.Next()
a.dbKey = a.dbIter.Key()
} else if a.moveMemOrDb == 2 {
a.memMoveNext = a.memNext()
a.dbMoveNext = a.dbIter.Next()
a.dbKey = a.dbIter.Key()
}
}
if !a.memMoveNext && !a.dbMoveNext {
a.key = nil
a.value = nil
return false
}
if !a.dbMoveNext {
a.moveMemOrDb = 0
if a.ops[0].delete {
return a.Next()
}
a.key = a.ops[0].key
a.value = a.ops[0].value
return true
}
if !a.memMoveNext {
a.key = a.dbKey
a.value = a.dbIter.Value()
return true
}
memkey := a.ops[0].key
switch bytes.Compare(memkey, a.dbKey) {
case -1:
a.moveMemOrDb = 0
if a.ops[0].delete {
return a.Next()
}
a.key = memkey
a.value = a.ops[0].value
return true
case 0:
a.moveMemOrDb = 2
if a.ops[0].delete {
return a.Next()
}
a.key = memkey
a.value = a.ops[0].value
return true
case 1:
a.moveMemOrDb = 1
a.key = a.dbKey
a.value = a.dbIter.Value()
return true
}
return false
}
func (a *asyncdbIterator) memNext() bool {
a.ops = a.ops[1:]
return len(a.ops) > 0
}
func (a *asyncdbIterator) Key() []byte {
if len(a.ops) == 0 {
return a.dbIter.Key()
}
return a.key
}
func (a *asyncdbIterator) Value() []byte {
if len(a.ops) == 0 {
return a.dbIter.Value()
}
return a.value
}
func (a *asyncdbIterator) Error() error {
return a.dbIter.Error()
}
func (a *asyncdbIterator) Release() {
a.dbIter.Release()
}