Golang Iterator.Next方法代碼示例

func checkIteratorContains(ts graph.TripleStore, it graph.Iterator, expected []string, t *testing.T) {
	var actual []string
	actual = nil
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		actual = append(actual, ts.GetNameFor(val))
	}
	actualSet := actual[:]
	for _, a := range expected {
		found := false
		for j, b := range actualSet {
			if a == b {
				actualSet = append(actualSet[:j], actualSet[j+1:]...)
				found = true
				break
			}
		}
		if !found {
			t.Error("Couldn't find", a, "in actual output.\nActual:", actual, "\nExpected: ", expected, "\nRemainder: ", actualSet)
			return
		}
	}
	if len(actualSet) != 0 {
		t.Error("Actual output has more than expected.\nActual:", actual, "\nExpected: ", expected, "\nRemainder: ", actualSet)
	}
}

func runIteratorWithCallback(it graph.Iterator, ses *Session, callback otto.Value, this otto.FunctionCall, limit int) {
	count := 0
	it, _ = it.Optimize()
	for {
		if ses.doHalt {
			return
		}
		_, ok := it.Next()
		if !ok {
			break
		}
		tags := make(map[string]graph.TSVal)
		it.TagResults(&tags)
		val, _ := this.Otto.ToValue(tagsToValueMap(tags, ses))
		val, _ = callback.Call(this.This, val)
		count++
		if limit >= 0 && count >= limit {
			break
		}
		for it.NextResult() == true {
			if ses.doHalt {
				return
			}
			tags := make(map[string]graph.TSVal)
			it.TagResults(&tags)
			val, _ := this.Otto.ToValue(tagsToValueMap(tags, ses))
			val, _ = callback.Call(this.This, val)
			count++
			if limit >= 0 && count >= limit {
				break
			}
		}
	}
	it.Close()
}

func runIteratorToArray(it graph.Iterator, ses *Session, limit int) []map[string]string {
	output := make([]map[string]string, 0)
	count := 0
	it, _ = it.Optimize()
	for {
		if ses.doHalt {
			return nil
		}
		_, ok := it.Next()
		if !ok {
			break
		}
		tags := make(map[string]graph.TSVal)
		it.TagResults(&tags)
		output = append(output, tagsToValueMap(tags, ses))
		count++
		if limit >= 0 && count >= limit {
			break
		}
		for it.NextResult() == true {
			if ses.doHalt {
				return nil
			}
			tags := make(map[string]graph.TSVal)
			it.TagResults(&tags)
			output = append(output, tagsToValueMap(tags, ses))
			count++
			if limit >= 0 && count >= limit {
				break
			}
		}
	}
	it.Close()
	return output
}

func extractValuesFromIterator(ts graph.TripleStore, it graph.Iterator) []string {
	var output []string
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		output = append(output, ts.GetNameFor(val))
	}
	return output
}

func extractTripleFromIterator(ts graph.TripleStore, it graph.Iterator) []string {
	var output []string
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		output = append(output, ts.GetTriple(val).ToString())
	}
	return output
}

func extractNumbersFromIterator(it graph.Iterator) []int {
	var outputNumbers []int
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		outputNumbers = append(outputNumbers, val.(int))
	}
	return outputNumbers
}

func iterated(it graph.Iterator) []int {
	var res []int
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		res = append(res, val.(int))
	}
	return res
}

func iteratedNames(ts graph.TripleStore, it graph.Iterator) []string {
	var res []string
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		res = append(res, ts.NameOf(val))
	}
	sort.Strings(res)
	return res
}

func iteratedTriples(ts graph.TripleStore, it graph.Iterator) []*graph.Triple {
	var res ordered
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		res = append(res, ts.Triple(val))
	}
	sort.Sort(res)
	return res
}

func runIteratorToArrayNoTags(it graph.Iterator, ses *Session, limit int) []string {
	output := make([]string, 0)
	count := 0
	it, _ = it.Optimize()
	for {
		if ses.doHalt {
			return nil
		}
		val, ok := it.Next()
		if !ok {
			break
		}
		output = append(output, ses.ts.GetNameFor(val))
		count++
		if limit >= 0 && count >= limit {
			break
		}
	}
	it.Close()
	return output
}

func runIteratorOnSession(it graph.Iterator, ses *Session) {
	if ses.lookingForQueryShape {
		iterator.OutputQueryShapeForIterator(it, ses.ts, &(ses.queryShape))
		return
	}
	it, _ = it.Optimize()
	glog.V(2).Infoln(it.DebugString(0))
	for {
		// TODO(barakmich): Better halting.
		if ses.doHalt {
			return
		}
		_, ok := it.Next()
		if !ok {
			break
		}
		tags := make(map[string]graph.TSVal)
		it.TagResults(&tags)
		cont := ses.SendResult(&GremlinResult{metaresult: false, err: "", val: nil, actualResults: &tags})
		if !cont {
			break
		}
		for it.NextResult() == true {
			if ses.doHalt {
				return
			}
			tags := make(map[string]graph.TSVal)
			it.TagResults(&tags)
			cont := ses.SendResult(&GremlinResult{metaresult: false, err: "", val: nil, actualResults: &tags})
			if !cont {
				break
			}
		}
	}
	it.Close()
}

func TestIterator(t *testing.T) {
	var ts *LevelDBTripleStore

	Convey("Given a prepared database", t, func() {
		tmpDir, _ := ioutil.TempDir(os.TempDir(), "cayley_test")
		t.Log(tmpDir)
		defer os.RemoveAll(tmpDir)
		ok := CreateNewLevelDB(tmpDir)
		So(ok, ShouldBeTrue)
		ts = NewDefaultLevelDBTripleStore(tmpDir, nil)
		ts.AddTripleSet(makeTripleSet())
		var it graph.Iterator

		Convey("Can create an all iterator for nodes", func() {
			it = ts.GetNodesAllIterator()
			So(it, ShouldNotBeNil)

			Convey("Has basics", func() {
				size, accurate := it.Size()
				So(size, ShouldBeBetween, 0, 20)
				So(accurate, ShouldBeFalse)
				So(it.Type(), ShouldEqual, "all")
				re_it, ok := it.Optimize()
				So(ok, ShouldBeFalse)
				So(re_it, ShouldPointTo, it)
			})

			Convey("Iterates all nodes", func() {
				expected := []string{
					"A",
					"B",
					"C",
					"D",
					"E",
					"F",
					"G",
					"follows",
					"status",
					"cool",
					"status_graph",
				}
				sort.Strings(expected)
				actual := extractValuesFromIterator(ts, it)
				sort.Strings(actual)
				So(actual, ShouldResemble, expected)
				it.Reset()
				actual = extractValuesFromIterator(ts, it)
				sort.Strings(actual)
				So(actual, ShouldResemble, expected)

			})

			Convey("Contains a couple nodes", func() {
				So(it.Check(ts.GetIdFor("A")), ShouldBeTrue)
				So(it.Check(ts.GetIdFor("cool")), ShouldBeTrue)
				//So(it.Check(ts.GetIdFor("baller")), ShouldBeFalse)
			})

			Reset(func() {
				it.Reset()
			})
		})

		Convey("Can create an all iterator for edges", func() {
			it := ts.GetTriplesAllIterator()
			So(it, ShouldNotBeNil)
			Convey("Has basics", func() {
				size, accurate := it.Size()
				So(size, ShouldBeBetween, 0, 20)
				So(accurate, ShouldBeFalse)
				So(it.Type(), ShouldEqual, "all")
				re_it, ok := it.Optimize()
				So(ok, ShouldBeFalse)
				So(re_it, ShouldPointTo, it)
			})

			Convey("Iterates an edge", func() {
				edge_val, _ := it.Next()
				triple := ts.GetTriple(edge_val)
				set := makeTripleSet()
				var string_set []string
				for _, t := range set {
					string_set = append(string_set, t.ToString())
				}
				So(triple.ToString(), ShouldBeIn, string_set)
			})

			Reset(func() {
				ts.Close()
			})
		})
	})

}

func TestIterator(t *testing.T) {
	tmpDir, err := ioutil.TempDir(os.TempDir(), "cayley_test")
	if err != nil {
		t.Fatalf("Could not create working directory: %v", err)
	}
	defer os.RemoveAll(tmpDir)
	t.Log(tmpDir)

	err = createNewLevelDB(tmpDir, nil)
	if err != nil {
		t.Fatal("Failed to create LevelDB database.")
	}

	ts, err := newTripleStore(tmpDir, nil)
	if ts == nil || err != nil {
		t.Error("Failed to create leveldb TripleStore.")
	}
	ts.AddTripleSet(makeTripleSet())
	var it graph.Iterator

	it = ts.NodesAllIterator()
	if it == nil {
		t.Fatal("Got nil iterator.")
	}

	size, exact := it.Size()
	if size <= 0 || size >= 20 {
		t.Errorf("Unexpected size, got:%d expect:(0, 20)", size)
	}
	if exact {
		t.Errorf("Got unexpected exact result.")
	}
	if typ := it.Type(); typ != graph.All {
		t.Errorf("Unexpected iterator type, got:%v expect:%v", typ, graph.All)
	}
	optIt, changed := it.Optimize()
	if changed || optIt != it {
		t.Errorf("Optimize unexpectedly changed iterator.")
	}

	expect := []string{
		"A",
		"B",
		"C",
		"D",
		"E",
		"F",
		"G",
		"follows",
		"status",
		"cool",
		"status_graph",
	}
	sort.Strings(expect)
	for i := 0; i < 2; i++ {
		got := iteratedNames(ts, it)
		sort.Strings(got)
		if !reflect.DeepEqual(got, expect) {
			t.Errorf("Unexpected iterated result on repeat %d, got:%v expect:%v", i, got, expect)
		}
		it.Reset()
	}

	for _, pq := range expect {
		if !it.Check(ts.ValueOf(pq)) {
			t.Errorf("Failed to find and check %q correctly", pq)
		}
	}
	// FIXME(kortschak) Why does this fail?
	/*
		for _, pq := range []string{"baller"} {
			if it.Check(ts.ValueOf(pq)) {
				t.Errorf("Failed to check %q correctly", pq)
			}
		}
	*/
	it.Reset()

	it = ts.TriplesAllIterator()
	edge, _ := it.Next()
	triple := ts.Triple(edge)
	set := makeTripleSet()
	var ok bool
	for _, t := range set {
		if t.String() == triple.String() {
			ok = true
			break
		}
	}
	if !ok {
		t.Errorf("Failed to find %q during iteration, got:%q", triple, set)
	}

	ts.Close()
}

func (qs *queryShape) MakeNode(it graph.Iterator) *Node {
	n := Node{Id: qs.nodeId}
	for _, tag := range it.Tags() {
		n.Tags = append(n.Tags, tag)
	}
	for k, _ := range it.FixedTags() {
		n.Tags = append(n.Tags, k)
	}

	switch it.Type() {
	case graph.And:
		for _, sub := range it.SubIterators() {
			qs.nodeId++
			newNode := qs.MakeNode(sub)
			if sub.Type() != graph.Or {
				qs.StealNode(&n, newNode)
			} else {
				qs.AddNode(newNode)
				qs.AddLink(&Link{n.Id, newNode.Id, 0, 0})
			}
		}
	case graph.Fixed:
		n.IsFixed = true
		for {
			val, more := it.Next()
			if !more {
				break
			}
			n.Values = append(n.Values, qs.ts.NameOf(val))
		}
	case graph.HasA:
		hasa := it.(*HasA)
		qs.PushHasa(n.Id, hasa.dir)
		qs.nodeId++
		newNode := qs.MakeNode(hasa.primaryIt)
		qs.AddNode(newNode)
		qs.RemoveHasa()
	case graph.Or:
		for _, sub := range it.SubIterators() {
			qs.nodeId++
			newNode := qs.MakeNode(sub)
			if sub.Type() == graph.Or {
				qs.StealNode(&n, newNode)
			} else {
				qs.AddNode(newNode)
				qs.AddLink(&Link{n.Id, newNode.Id, 0, 0})
			}
		}
	case graph.LinksTo:
		n.IsLinkNode = true
		lto := it.(*LinksTo)
		qs.nodeId++
		newNode := qs.MakeNode(lto.primaryIt)
		hasaID, hasaDir := qs.LastHasa()
		if (hasaDir == graph.Subject && lto.dir == graph.Object) ||
			(hasaDir == graph.Object && lto.dir == graph.Subject) {
			qs.AddNode(newNode)
			if hasaDir == graph.Subject {
				qs.AddLink(&Link{hasaID, newNode.Id, 0, n.Id})
			} else {
				qs.AddLink(&Link{newNode.Id, hasaID, 0, n.Id})
			}
		} else if lto.primaryIt.Type() == graph.Fixed {
			qs.StealNode(&n, newNode)
		} else {
			qs.AddNode(newNode)
		}
	case graph.Optional:
		// Unsupported, for the moment
		fallthrough
	case graph.All:
	}
	return &n
}