Destutter filenames

graph/leveldb/all_iterator.go

@@ -0,0 +1,134 @@
+// Copyright 2014 The Cayley Authors. All rights reserved.
+//
+// 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 leveldb
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+
+	leveldb_it "github.com/syndtr/goleveldb/leveldb/iterator"
+	leveldb_opt "github.com/syndtr/goleveldb/leveldb/opt"
+
+	"github.com/google/cayley/graph"
+)
+
+type LevelDBAllIterator struct {
+	graph.BaseIterator
+	prefix []byte
+	dir    string
+	open   bool
+	it     leveldb_it.Iterator
+	ts     *LevelDBTripleStore
+	ro     *leveldb_opt.ReadOptions
+}
+
+func NewLevelDBAllIterator(prefix, dir string, ts *LevelDBTripleStore) *LevelDBAllIterator {
+	var it LevelDBAllIterator
+	graph.BaseIteratorInit(&it.BaseIterator)
+	it.ro = &leveldb_opt.ReadOptions{}
+	it.ro.DontFillCache = true
+	it.it = ts.db.NewIterator(nil, it.ro)
+	it.prefix = []byte(prefix)
+	it.dir = dir
+	it.open = true
+	it.ts = ts
+	it.it.Seek(it.prefix)
+	if !it.it.Valid() {
+		it.open = false
+		it.it.Release()
+	}
+	return &it
+}
+
+func (a *LevelDBAllIterator) Reset() {
+	if !a.open {
+		a.it = a.ts.db.NewIterator(nil, a.ro)
+		a.open = true
+	}
+	a.it.Seek(a.prefix)
+	if !a.it.Valid() {
+		a.open = false
+		a.it.Release()
+	}
+}
+
+func (a *LevelDBAllIterator) Clone() graph.Iterator {
+	out := NewLevelDBAllIterator(string(a.prefix), a.dir, a.ts)
+	out.CopyTagsFrom(a)
+	return out
+}
+
+func (a *LevelDBAllIterator) Next() (graph.TSVal, bool) {
+	if !a.open {
+		a.Last = nil
+		return nil, false
+	}
+	var out []byte
+	out = make([]byte, len(a.it.Key()))
+	copy(out, a.it.Key())
+	a.it.Next()
+	if !a.it.Valid() {
+		a.Close()
+	}
+	if !bytes.HasPrefix(out, a.prefix) {
+		a.Close()
+		return nil, false
+	}
+	a.Last = out
+	return out, true
+}
+
+func (a *LevelDBAllIterator) Check(v graph.TSVal) bool {
+	a.Last = v
+	return true
+}
+
+func (lit *LevelDBAllIterator) Close() {
+	if lit.open {
+		lit.it.Release()
+		lit.open = false
+	}
+}
+
+func (a *LevelDBAllIterator) Size() (int64, bool) {
+	size, err := a.ts.GetApproximateSizeForPrefix(a.prefix)
+	if err == nil {
+		return size, false
+	}
+	// INT64_MAX
+	return int64(^uint64(0) >> 1), false
+}
+
+func (lit *LevelDBAllIterator) DebugString(indent int) string {
+	size, _ := lit.Size()
+	return fmt.Sprintf("%s(%s tags: %v leveldb size:%d %s %p)", strings.Repeat(" ", indent), lit.Type(), lit.Tags(), size, lit.dir, lit)
+}
+
+func (lit *LevelDBAllIterator) Type() string { return "all" }
+func (lit *LevelDBAllIterator) Sorted() bool { return false }
+
+func (lit *LevelDBAllIterator) Optimize() (graph.Iterator, bool) {
+	return lit, false
+}
+
+func (lit *LevelDBAllIterator) GetStats() *graph.IteratorStats {
+	s, _ := lit.Size()
+	return &graph.IteratorStats{
+		CheckCost: 1,
+		NextCost:  2,
+		Size:      s,
+	}
+}