| // Copyright 2015 The LUCI Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package memory |
| |
| import ( |
| "bytes" |
| |
| "go.chromium.org/luci/gae/service/datastore" |
| |
| "github.com/luci/gtreap" |
| "go.chromium.org/luci/common/data/treapstore" |
| ) |
| |
| type storeEntry struct { |
| key []byte |
| value []byte |
| } |
| |
| // storeEntryCompare is a gtreap.Compare function for *storeEntry. |
| func storeEntryCompare(a, b interface{}) int { |
| // TODO(dnj): Investigate optimizing this by removing the type assertions, |
| // either by explicitly tailoring gtreap / treapstore to use []byte or by |
| // optimizing via special-case interface. |
| return bytes.Compare(a.(*storeEntry).key, b.(*storeEntry).key) |
| } |
| |
| func memStoreCollide(o, n memCollection, f func(k, ov, nv []byte)) { |
| var oldIter, newIter memIterator |
| if o != nil { |
| if !o.IsReadOnly() { |
| panic("old collection is r/w") |
| } |
| oldIter = o.Iterator(nil) |
| } else { |
| oldIter = nilIterator{} |
| } |
| |
| if n != nil { |
| if !n.IsReadOnly() { |
| panic("new collection is r/w") |
| } |
| newIter = n.Iterator(nil) |
| } else { |
| newIter = nilIterator{} |
| } |
| |
| l, r := oldIter.Next(), newIter.Next() |
| for { |
| switch { |
| case l == nil: |
| // No more "old" items, use up the rest of "new" and finish. |
| for r != nil { |
| f(r.key, nil, r.value) |
| r = newIter.Next() |
| } |
| return |
| |
| case r == nil: |
| // No more "new" items, use up the rest of "old" and finish. |
| for l != nil { |
| f(l.key, l.value, nil) |
| l = oldIter.Next() |
| } |
| return |
| |
| default: |
| switch bytes.Compare(l.key, r.key) { |
| case -1: // l < r |
| f(l.key, l.value, nil) |
| l = oldIter.Next() |
| case 0: // l == r |
| f(l.key, l.value, r.value) |
| l, r = oldIter.Next(), newIter.Next() |
| case 1: // l > r |
| f(r.key, nil, r.value) |
| r = newIter.Next() |
| } |
| } |
| } |
| } |
| |
| // memStore is a generic interface modeled after treapstore.Store. |
| type memStore interface { |
| datastore.TestingSnapshot |
| |
| GetCollection(name string) memCollection |
| GetCollectionNames() []string |
| GetOrCreateCollection(name string) memCollection |
| Snapshot() memStore |
| |
| IsReadOnly() bool |
| } |
| |
| // memIterator is an iterator over a memStore's contents. |
| type memIterator interface { |
| Next() *storeEntry |
| } |
| |
| // memVisitor is a callback for ForEachItem. |
| type memVisitor func(k, v []byte) bool |
| |
| // memCollection is a generic interface modeled after treapstore.Collection. |
| type memCollection interface { |
| Name() string |
| Delete(k []byte) |
| Get(k []byte) []byte |
| MinItem() *storeEntry |
| Set(k, v []byte) |
| Iterator(pivot []byte) memIterator |
| ForEachItem(memVisitor) |
| |
| IsReadOnly() bool |
| } |
| |
| type memStoreImpl struct { |
| s *treapstore.Store |
| } |
| |
| var _ memStore = (*memStoreImpl)(nil) |
| |
| func (*memStoreImpl) ImATestingSnapshot() {} |
| |
| func (ms *memStoreImpl) IsReadOnly() bool { return ms.s.IsReadOnly() } |
| |
| func newMemStore() memStore { |
| ret := memStore(&memStoreImpl{treapstore.New()}) |
| if *logMemCollectionFolder != "" { |
| ret = wrapTracingMemStore(ret) |
| } |
| return ret |
| } |
| |
| func (ms *memStoreImpl) Snapshot() memStore { |
| if ms.s.IsReadOnly() { |
| return ms |
| } |
| return &memStoreImpl{ms.s.Snapshot()} |
| } |
| |
| func (ms *memStoreImpl) GetCollection(name string) memCollection { |
| coll := ms.s.GetCollection(name) |
| if coll == nil { |
| return nil |
| } |
| return &memCollectionImpl{coll} |
| } |
| |
| func (ms *memStoreImpl) GetOrCreateCollection(name string) memCollection { |
| coll := ms.s.GetCollection(name) |
| if coll == nil { |
| coll = ms.s.CreateCollection(name, storeEntryCompare) |
| } |
| return &memCollectionImpl{coll} |
| } |
| |
| func (ms *memStoreImpl) GetCollectionNames() []string { return ms.s.GetCollectionNames() } |
| |
| type memIteratorImpl struct { |
| base *gtreap.Iterator |
| } |
| |
| func (it *memIteratorImpl) Next() *storeEntry { |
| v, ok := it.base.Next() |
| if !ok { |
| return nil |
| } |
| return v.(*storeEntry) |
| } |
| |
| type memCollectionImpl struct { |
| c *treapstore.Collection |
| } |
| |
| var _ memCollection = (*memCollectionImpl)(nil) |
| |
| func (mc *memCollectionImpl) Name() string { return mc.c.Name() } |
| func (mc *memCollectionImpl) IsReadOnly() bool { return mc.c.IsReadOnly() } |
| |
| func (mc *memCollectionImpl) Get(k []byte) []byte { |
| if ent := mc.c.Get(storeKey(k)); ent != nil { |
| return ent.(*storeEntry).value |
| } |
| return nil |
| } |
| |
| func (mc *memCollectionImpl) MinItem() *storeEntry { |
| ent, _ := mc.c.Min().(*storeEntry) |
| return ent |
| } |
| |
| func (mc *memCollectionImpl) Set(k, v []byte) { mc.c.Put(&storeEntry{k, v}) } |
| func (mc *memCollectionImpl) Delete(k []byte) { mc.c.Delete(storeKey(k)) } |
| |
| func (mc *memCollectionImpl) Iterator(target []byte) memIterator { |
| if !mc.c.IsReadOnly() { |
| // We prevent this to ensure our internal logic, not because it's actually |
| // an invalid operation. |
| panic("attempting to get Iterator from r/w memCollection") |
| } |
| return &memIteratorImpl{mc.c.Iterator(storeKey(target))} |
| } |
| |
| func (mc *memCollectionImpl) ForEachItem(fn memVisitor) { |
| mc.c.VisitAscend(storeKey(nil), func(it gtreap.Item) bool { |
| ent := it.(*storeEntry) |
| return fn(ent.key, ent.value) |
| }) |
| } |
| |
| func storeKey(k []byte) *storeEntry { return &storeEntry{k, nil} } |
| |
| // nilIterator is a memIterator that begins in a depleted state. |
| type nilIterator struct{} |
| |
| func (it nilIterator) Next() *storeEntry { return nil } |