iterator: replace Describe method with a helper

graph/bolt/all_iterator.go

@@ -26,6 +26,8 @@ import (
 	"github.com/cayleygraph/cayley/quad"
 )
 
+var _ graph.Iterator = &AllIterator{}
+
 type AllIterator struct {
 	nodes  bool
 	uid    uint64
@@ -176,15 +178,8 @@ func (it *AllIterator) Size() (int64, bool) {
 	return it.qs.Size(), true
 }
 
-func (it *AllIterator) Describe() graph.Description {
-	size, _ := it.Size()
-	return graph.Description{
-		UID:       it.UID(),
-		Type:      it.Type(),
-		Tags:      it.tags.Tags(),
-		Size:      size,
-		Direction: it.dir,
-	}
+func (it *AllIterator) String() string {
+	return fmt.Sprintf("BoltAll(%q)", it.bucket)
 }
 
 func (it *AllIterator) Type() graph.Type { return graph.All }
@@ -203,5 +198,3 @@ func (it *AllIterator) Stats() graph.IteratorStats {
 		ExactSize:    exact,
 	}
 }
-
-var _ graph.Iterator = &AllIterator{}

graph/bolt/iterator.go

@@ -27,6 +27,8 @@ import (
 	"github.com/cayleygraph/cayley/quad"
 )
 
+var _ graph.Iterator = &Iterator{}
+
 var (
 	bufferSize  = 50
 	errNotExist = errors.New("quad does not exist")
@@ -269,20 +271,8 @@ func (it *Iterator) Size() (int64, bool) {
 	return it.size, true
 }
 
-func (it *Iterator) Describe() graph.Description {
-	nameOf := it.qs.NameOf(&Token{
-		nodes:  true,
-		bucket: it.bucket,
-		key:    it.checkID,
-	})
-	return graph.Description{
-		UID:       it.UID(),
-		Name:      quad.StringOf(nameOf),
-		Type:      it.Type(),
-		Tags:      it.tags.Tags(),
-		Size:      it.size,
-		Direction: it.dir,
-	}
+func (it *Iterator) String() string {
+	return fmt.Sprintf("BoltIter(%q)", it.bucket)
 }
 
 func (it *Iterator) Type() graph.Type { return "bolt" }
@@ -301,5 +291,3 @@ func (it *Iterator) Stats() graph.IteratorStats {
 		ExactSize:    exact,
 	}
 }
-
-var _ graph.Iterator = &Iterator{}

graph/elastic/iterator.go

@@ -16,11 +16,12 @@ package elastic
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/cayleygraph/cayley/graph"
 	"github.com/cayleygraph/cayley/graph/iterator"
 	"github.com/cayleygraph/cayley/quad"
-	elastic "gopkg.in/olivere/elastic.v5"
+	"gopkg.in/olivere/elastic.v5"
 )
 
 // Iterator struct used for elastic backend
@@ -232,15 +233,8 @@ func (it *Iterator) SubIterators() []graph.Iterator {
 	return nil
 }
 
-// Describe gives the graph description
-func (it *Iterator) Describe() graph.Description {
-	size, _ := it.Size()
-	return graph.Description{
-		UID:  it.UID(),
-		Name: string(it.hash),
-		Type: it.Type(),
-		Size: size,
-	}
+func (it *Iterator) String() string {
+	return fmt.Sprintf("Elastic(%v)", it.resultType)
 }
 
 // Close closes the iterator

graph/gaedatastore/iterator.go

@@ -297,16 +297,8 @@ func (it *Iterator) Type() graph.Type {
 }
 func (it *Iterator) Sorted() bool                     { return false }
 func (it *Iterator) Optimize() (graph.Iterator, bool) { return it, false }
-func (it *Iterator) Describe() graph.Description {
-	size, _ := it.Size()
-	return graph.Description{
-		UID:       it.UID(),
-		Name:      fmt.Sprintf("%s/%s", it.name, it.hash),
-		Type:      it.Type(),
-		Size:      size,
-		Tags:      it.tags.Tags(),
-		Direction: it.dir,
-	}
+func (it *Iterator) String() string {
+	return fmt.Sprintf("GAE(%s/%s)", it.name, it.hash)
 }
 
 // TODO (panamafrancis) calculate costs

graph/gaedatastore/quadstore_test.go

@@ -125,8 +125,8 @@ func TestIterators(t *testing.T) {
 	// Test cloning an iterator
 	var it2 graph.Iterator
 	it2 = it.Clone()
-	x := it2.Describe()
-	y := it.Describe()
+	x := graph.DescribeIterator(it2)
+	y := graph.DescribeIterator(it)
 
 	require.Equal(t, y.Name, x.Name, "Iterator Clone was not successful")
 }

graph/iterate.go

@@ -70,7 +70,7 @@ func (c *IterateChain) start() {
 	if !clog.V(2) {
 		return
 	}
-	if b, err := json.MarshalIndent(c.it.Describe(), "", "  "); err != nil {
+	if b, err := json.MarshalIndent(DescribeIterator(c.it), "", "  "); err != nil {
 		clog.Infof("failed to format description: %v", err)
 	} else {
 		clog.Infof("%s", b)

graph/iterator.go

@@ -90,6 +90,9 @@ func (t *Tagger) CopyFromTagger(st *Tagger) {
 }
 
 type Iterator interface {
+	// String returns a short textual representation of an iterator.
+	String() string
+
 	Tagger() *Tagger
 
 	// Fills a tag-to-result-value map.
@@ -162,25 +165,39 @@ type Iterator interface {
 	// Return a slice of the subiterators for this iterator.
 	SubIterators() []Iterator
 
-	// Return a string representation of the iterator.
-	Describe() Description
-
 	// Close the iterator and do internal cleanup.
 	Close() error
 
 	// UID returns the unique identifier of the iterator.
 	UID() uint64
 }
 
+// DescribeIterator returns a description of the iterator tree.
+func DescribeIterator(it Iterator) Description {
+	sz, _ := it.Size()
+	d := Description{
+		UID:  it.UID(),
+		Name: it.String(),
+		Type: it.Type(),
+		Tags: it.Tagger().Tags(),
+		Size: sz,
+	}
+	if sub := it.SubIterators(); len(sub) != 0 {
+		d.Iterators = make([]Description, 0, len(sub))
+		for _, sit := range sub {
+			d.Iterators = append(d.Iterators, DescribeIterator(sit))
+		}
+	}
+	return d
+}
+
 type Description struct {
-	UID       uint64         `json:",omitempty"`
-	Name      string         `json:",omitempty"`
-	Type      Type           `json:",omitempty"`
-	Tags      []string       `json:",omitempty"`
-	Size      int64          `json:",omitempty"`
-	Direction quad.Direction `json:",omitempty"`
-	Iterator  *Description   `json:",omitempty"`
-	Iterators []Description  `json:",omitempty"`
+	UID       uint64        `json:",omitempty"`
+	Name      string        `json:",omitempty"`
+	Type      Type          `json:",omitempty"`
+	Tags      []string      `json:",omitempty"`
+	Size      int64         `json:",omitempty"`
+	Iterators []Description `json:",omitempty"`
 }
 
 // ApplyMorphism is a curried function that can generates a new iterator based on some prior iterator.

graph/iterator/all.go

@@ -23,9 +23,12 @@ package iterator
 // the base iterators, and it helps just to see it here.
 
 import (
+	"fmt"
 	"github.com/cayleygraph/cayley/graph"
 )
 
+var _ graph.Iterator = &Int64{}
+
 // An All iterator across a range of int64 values, from `max` to `min`.
 type Int64 struct {
 	node     bool
@@ -88,12 +91,8 @@ func (it *Int64) TagResults(dst map[string]graph.Value) {
 	it.tags.TagResult(dst, it.Result())
 }
 
-func (it *Int64) Describe() graph.Description {
-	return graph.Description{
-		UID:  it.UID(),
-		Type: it.Type(),
-		Tags: it.tags.Tags(),
-	}
+func (it *Int64) String() string {
+	return fmt.Sprintf("Int64(%d-%d)", it.min, it.max)
 }
 
 // Next() on an Int64 all iterator is a simple incrementing counter.
@@ -140,8 +139,8 @@ func (it *Int64) SubIterators() []graph.Iterator {
 // The number of elements in an Int64 is the size of the range.
 // The size is exact.
 func (it *Int64) Size() (int64, bool) {
-	Size := ((it.max - it.min) + 1)
-	return Size, true
+	sz := (it.max - it.min) + 1
+	return sz, true
 }
 
 func valToInt64(v graph.Value) int64 {
@@ -184,5 +183,3 @@ func (it *Int64) Stats() graph.IteratorStats {
 		Contains:     it.runstats.Contains,
 	}
 }
-
-var _ graph.Iterator = &Int64{}

graph/iterator/and.go

@@ -19,6 +19,8 @@ import (
 	"github.com/cayleygraph/cayley/graph"
 )
 
+var _ graph.Iterator = &And{}
+
 // The And iterator. Consists of a number of subiterators, the primary of which will
 // be Next()ed if next is called.
 type And struct {
@@ -100,19 +102,8 @@ func (it *And) SubIterators() []graph.Iterator {
 	return iters
 }
 
-func (it *And) Describe() graph.Description {
-	subIts := make([]graph.Description, len(it.internalIterators))
-	for i, sub := range it.internalIterators {
-		subIts[i] = sub.Describe()
-	}
-	primary := it.primaryIt.Describe()
-	return graph.Description{
-		UID:       it.UID(),
-		Type:      it.Type(),
-		Tags:      it.tags.Tags(),
-		Iterator:  &primary,
-		Iterators: subIts,
-	}
+func (it *And) String() string {
+	return "And"
 }
 
 // Add a subiterator to this And iterator.
@@ -306,5 +297,3 @@ func (it *And) Close() error {
 
 // Register this as an "and" iterator.
 func (it *And) Type() graph.Type { return graph.And }
-
-var _ graph.Iterator = &And{}

graph/iterator/count.go

@@ -5,6 +5,8 @@ import (
 	"github.com/cayleygraph/cayley/quad"
 )
 
+var _ graph.Iterator = &Count{}
+
 // Count iterator returns one element with size of underlying iterator.
 type Count struct {
 	uid    uint64
@@ -128,16 +130,4 @@ func (it *Count) Size() (int64, bool) {
 	return 1, true
 }
 
-func (it *Count) Describe() graph.Description {
-	subIts := []graph.Description{
-		it.it.Describe(),
-	}
-	return graph.Description{
-		UID:       it.UID(),
-		Type:      it.Type(),
-		Tags:      it.Tagger().Tags(),
-		Iterators: subIts,
-	}
-}
-
-var _ graph.Iterator = &Count{}
+func (it *Count) String() string { return "Count" }

graph/iterator/fixed.go

@@ -22,11 +22,12 @@ package iterator
 
 import (
 	"fmt"
-	"sort"
 
 	"github.com/cayleygraph/cayley/graph"
 )
 
+var _ graph.Iterator = &Fixed{}
+
 // A Fixed iterator consists of it's values, an index (where it is in the process of Next()ing) and
 // an equality function.
 type Fixed struct {
@@ -93,23 +94,8 @@ func (it *Fixed) Add(v graph.Value) {
 	it.values = append(it.values, v)
 }
 
-func (it *Fixed) Describe() graph.Description {
-	var value string
-	if len(it.values) > 0 {
-		value = fmt.Sprint(it.values[0])
-	}
-	fixed := make([]string, 0, len(it.tags.Fixed()))
-	for k := range it.tags.Fixed() {
-		fixed = append(fixed, k)
-	}
-	sort.Strings(fixed)
-	return graph.Description{
-		UID:  it.UID(),
-		Name: value,
-		Type: it.Type(),
-		Tags: fixed,
-		Size: int64(len(it.values)),
-	}
+func (it *Fixed) String() string {
+	return fmt.Sprintf("Fixed(%v)", it.values)
 }
 
 // Register this iterator as a Fixed iterator.
@@ -186,5 +172,3 @@ func (it *Fixed) Stats() graph.IteratorStats {
 		ExactSize:    exact,
 	}
 }
-
-var _ graph.Iterator = &Fixed{}

graph/iterator/hasa.go

@@ -36,10 +36,13 @@ package iterator
 import (
 	"github.com/cayleygraph/cayley/clog"
 
+	"fmt"
 	"github.com/cayleygraph/cayley/graph"
 	"github.com/cayleygraph/cayley/quad"
 )
 
+var _ graph.Iterator = &HasA{}
+
 // A HasA consists of a reference back to the graph.QuadStore that it references,
 // a primary subiterator, a direction in which the quads for that subiterator point,
 // and a temporary holder for the iterator generated on Contains().
@@ -123,15 +126,8 @@ func (it *HasA) TagResults(dst map[string]graph.Value) {
 	it.primaryIt.TagResults(dst)
 }
 
-func (it *HasA) Describe() graph.Description {
-	primary := it.primaryIt.Describe()
-	return graph.Description{
-		UID:       it.UID(),
-		Type:      it.Type(),
-		Tags:      it.tags.Tags(),
-		Direction: it.dir,
-		Iterator:  &primary,
-	}
+func (it *HasA) String() string {
+	return fmt.Sprintf("HasA(%v)", it.dir)
 }
 
 // Check a value against our internal iterator. In order to do this, we must first open a new
@@ -281,5 +277,3 @@ func (it *HasA) Size() (int64, bool) {
 	st := it.Stats()
 	return st.Size, st.ExactSize
 }
-
-var _ graph.Iterator = &HasA{}