Add support for language in Exact Tokenizer

posting/index.go

@@ -439,13 +439,18 @@ func (l *List) AddMutationWithIndex(ctx context.Context, edge *pb.DirectedEdge,
 }
 
 // deleteTokensFor deletes the index for the given attribute and token.
-func deleteTokensFor(attr, tokenizerName string) error {
+func deleteTokensFor(attr, tokenizerName string, hasLang bool) error {
 	pk := x.ParsedKey{Attr: attr}
 	prefix := pk.IndexPrefix()
 	tokenizer, ok := tok.GetTokenizer(tokenizerName)
 	if !ok {
 		return errors.Errorf("Could not find valid tokenizer for %s", tokenizerName)
 	}
+	if hasLang {
+		// We just need the tokenizer identifier for ExactTokenizer having language.
+		// It will be same for all the language.
+		tokenizer = tok.GetLangTokenizer(tokenizer, "en")
+	}
 	prefix = append(prefix, tokenizer.Identifier())
 	if err := pstore.DropPrefix(prefix); err != nil {
 		return err
@@ -785,7 +790,13 @@ func rebuildIndex(ctx context.Context, rb *IndexRebuild) error {
 	glog.Infof("Deleting index for attr %s and tokenizers %s", rb.Attr,
 		rebuildInfo.tokenizersToDelete)
 	for _, tokenizer := range rebuildInfo.tokenizersToDelete {
-		if err := deleteTokensFor(rb.Attr, tokenizer); err != nil {
+		if err := deleteTokensFor(rb.Attr, tokenizer, false); err != nil {
+			return err
+		}
+		if tokenizer != "exact" {
+			continue
+		}
+		if err := deleteTokensFor(rb.Attr, tokenizer, true); err != nil {
 			return err
 		}
 	}
@@ -804,7 +815,13 @@ func rebuildIndex(ctx context.Context, rb *IndexRebuild) error {
 		rebuildInfo.tokenizersToRebuild)
 	// Before rebuilding, the existing index needs to be deleted.
 	for _, tokenizer := range rebuildInfo.tokenizersToRebuild {
-		if err := deleteTokensFor(rb.Attr, tokenizer); err != nil {
+		if err := deleteTokensFor(rb.Attr, tokenizer, false); err != nil {
+			return err
+		}
+		if tokenizer != "exact" {
+			continue
+		}
+		if err := deleteTokensFor(rb.Attr, tokenizer, true); err != nil {
 			return err
 		}
 	}
@@ -824,6 +841,7 @@ func rebuildIndex(ctx context.Context, rb *IndexRebuild) error {
 				Value: p.Value,
 				Tid:   types.TypeID(p.ValType),
 			}
+			edge.Lang = string(p.LangTag)
 
 			for {
 				err := txn.addIndexMutations(ctx, &indexMutationInfo{

query/common_test.go

@@ -294,9 +294,7 @@ noindex_age                    : int .
 noindex_dob                    : datetime .
 noindex_alive                  : bool .
 noindex_salary                 : float .
-language                       : [string] .\
-name_lang_index                : string @index(exact) @lang .
-name_index                	   : string @index(exact) .
+language                       : [string] .
 `
 
 func populateCluster() {
@@ -309,19 +307,6 @@ func populateCluster() {
 	testutil.AssignUids(100000)
 
 	err = addTriplesToCluster(`
-
-	<10101> <name_lang_index> "zon"@sv .
-	<10101> <name_lang_index> "öffnen"@de .
-	<10102> <name_lang_index> "öppna"@sv .
-	<10102> <name_lang_index> "zumachen"@de .
-
-
-	<10103> <name_index> "zon" .
-	<10104> <name_index> "öffnen" .
-	<10105> <name_index> "öppna" .
-	<10106> <name_index> "zumachen" .
-
-
 		<1> <name> "Michonne" .
 		<2> <name> "King Lear" .
 		<3> <name> "Margaret" .

testutil/client.go

@@ -67,7 +67,7 @@ func init() {
 		return port
 	}
 
-	grpcPort = getPort("TEST_PORT_ALPHA", 8180)
+	grpcPort = getPort("TEST_PORT_ALPHA", 9180)
 	SockAddr = fmt.Sprintf("localhost:%d", grpcPort)
 	SockAddrHttp = fmt.Sprintf("localhost:%d", grpcPort-1000)
 

tok/tok.go

@@ -93,7 +93,6 @@ func init() {
 	registerTokenizer(MonthTokenizer{})
 	registerTokenizer(DayTokenizer{})
 	registerTokenizer(ExactTokenizer{})
-	registerTokenizer(LangTokenizer{})
 	registerTokenizer(BoolTokenizer{})
 	registerTokenizer(TrigramTokenizer{})
 	registerTokenizer(HashTokenizer{})
@@ -292,34 +291,24 @@ func (t TermTokenizer) Identifier() byte { return IdentTerm }
 func (t TermTokenizer) IsSortable() bool { return false }
 func (t TermTokenizer) IsLossy() bool    { return true }
 
-// ExactTokenizer returns the exact string as a token.
-type ExactTokenizer struct{}
-
-func (t ExactTokenizer) Name() string { return "exact" }
-func (t ExactTokenizer) Type() string { return "string" }
-func (t ExactTokenizer) Tokens(v interface{}) ([]string, error) {
-	if term, ok := v.(string); ok {
-		return []string{term}, nil
-	}
-	return nil, errors.Errorf("Exact indices only supported for string types")
-}
-func (t ExactTokenizer) Identifier() byte { return IdentExact }
-func (t ExactTokenizer) IsSortable() bool { return true }
-func (t ExactTokenizer) IsLossy() bool    { return false }
-
-// LangTokenizer returns the exact string along with language prefix as a token.
-type LangTokenizer struct {
+// ExactTokenizer returns the exact string as a token. If collator is provided for
+// any language then it also adds the language in the prefix .
+type ExactTokenizer struct {
 	langBase string
 	cl       *collate.Collator
 	buffer   *collate.Buffer
 }
 
-func (t LangTokenizer) Name() string { return "lang" }
-func (t LangTokenizer) Type() string { return "string" }
-func (t LangTokenizer) Tokens(v interface{}) ([]string, error) {
+func (t ExactTokenizer) Name() string { return "exact" }
+func (t ExactTokenizer) Type() string { return "string" }
+func (t ExactTokenizer) Tokens(v interface{}) ([]string, error) {
 	val, ok := v.(string)
 	if !ok {
-		return nil, errors.Errorf("Lang indices only supported for string types")
+		return nil, errors.Errorf("Exact indices only supported for string types")
+	}
+
+	if t.cl == nil {
+		return []string{val}, nil
 	}
 
 	encodedTerm := t.cl.KeyFromString(t.buffer, val)
@@ -332,10 +321,19 @@ func (t LangTokenizer) Tokens(v interface{}) ([]string, error) {
 	t.buffer.Reset()
 	return []string{string(term)}, nil
 }
-func (t LangTokenizer) Identifier() byte { return IdentExactLang }
-func (t LangTokenizer) IsSortable() bool { return true }
-func (t LangTokenizer) IsLossy() bool    { return false }
-func (t LangTokenizer) Prefix() []byte {
+
+func (t ExactTokenizer) Identifier() byte {
+	if t.cl == nil {
+		return IdentExact
+	}
+	return IdentExactLang
+}
+func (t ExactTokenizer) IsSortable() bool { return true }
+func (t ExactTokenizer) IsLossy() bool    { return false }
+func (t ExactTokenizer) Prefix() []byte {
+	if t.cl == nil {
+		return []byte{IdentExact}
+	}
 	prefix := []byte{IdentExactLang}
 	prefix = append(prefix, []byte(t.langBase)...)
 	prefix = append(prefix, IdentDelimiter)

tok/tokens.go

@@ -42,7 +42,7 @@ func GetLangTokenizer(t Tokenizer, lang string) Tokenizer {
 		if err != nil {
 			langTag = enLangTag
 		}
-		return LangTokenizer{langBase: LangBase(lang), cl: collate.New(langTag),
+		return ExactTokenizer{langBase: LangBase(lang), cl: collate.New(langTag),
 			buffer: &collate.Buffer{}}
 	}
 	return t

worker/sort.go

@@ -225,13 +225,13 @@ func sortWithIndex(ctx context.Context, ts *pb.SortMessage) *sortresult {
 
 	var prefix []byte
 	if len(order.Langs) > 0 {
-		// Only one language is allowed.
+		// Only one languge is allowed.
 		lang := order.Langs[0]
 		tokenizer = tok.GetLangTokenizer(tokenizer, lang)
-		langTokenizer, ok := tokenizer.(tok.LangTokenizer)
+		langTokenizer, ok := tokenizer.(*tok.ExactTokenizer)
 		if !ok {
 			return resultWithError(errors.Errorf(
-				"Invalid tokenizer for language %s.", lang))
+				"Failed to get tokenizer for Attribute %s for language %s.", order.Attr, lang))
 		}
 		prefix = langTokenizer.Prefix()
 	} else {