Adding upstream version 2.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

analysis/tokenizer/exception/exception.go

@@ -0,0 +1,144 @@
+//  Copyright (c) 2015 Couchbase, Inc.
+//
+// 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 exception implements a Tokenizer which extracts pieces matched by a
+// regular expression from the input data, delegates the rest to another
+// tokenizer, then insert back extracted parts in the token stream. Use it to
+// preserve sequences which a regular tokenizer would alter or remove.
+//
+// Its constructor takes the following arguments:
+//
+// "exceptions" ([]string): one or more Go regular expressions matching the
+// sequence to preserve. Multiple expressions are combined with "|".
+//
+// "tokenizer" (string): the name of the tokenizer processing the data not
+// matched by "exceptions".
+package exception
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const Name = "exception"
+
+type ExceptionsTokenizer struct {
+	exception *regexp.Regexp
+	remaining analysis.Tokenizer
+}
+
+func NewExceptionsTokenizer(exception *regexp.Regexp, remaining analysis.Tokenizer) *ExceptionsTokenizer {
+	return &ExceptionsTokenizer{
+		exception: exception,
+		remaining: remaining,
+	}
+}
+
+func (t *ExceptionsTokenizer) Tokenize(input []byte) analysis.TokenStream {
+	rv := make(analysis.TokenStream, 0)
+	matches := t.exception.FindAllIndex(input, -1)
+	currInput := 0
+	lastPos := 0
+	for _, match := range matches {
+		start := match[0]
+		end := match[1]
+		if start > currInput {
+			// need to defer to remaining for unprocessed section
+			intermediate := t.remaining.Tokenize(input[currInput:start])
+			// add intermediate tokens to our result stream
+			for _, token := range intermediate {
+				// adjust token offsets
+				token.Position += lastPos
+				token.Start += currInput
+				token.End += currInput
+				rv = append(rv, token)
+			}
+			lastPos += len(intermediate)
+			currInput = start
+		}
+
+		// create single token with this regexp match
+		token := &analysis.Token{
+			Term:     input[start:end],
+			Start:    start,
+			End:      end,
+			Position: lastPos + 1,
+		}
+		rv = append(rv, token)
+		lastPos++
+		currInput = end
+
+	}
+
+	if currInput < len(input) {
+		// need to defer to remaining for unprocessed section
+		intermediate := t.remaining.Tokenize(input[currInput:])
+		// add intermediate tokens to our result stream
+		for _, token := range intermediate {
+			// adjust token offsets
+			token.Position += lastPos
+			token.Start += currInput
+			token.End += currInput
+			rv = append(rv, token)
+		}
+	}
+
+	return rv
+}
+
+func ExceptionsTokenizerConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.Tokenizer, error) {
+	exceptions := []string{}
+	iexceptions, ok := config["exceptions"].([]interface{})
+	if ok {
+		for _, exception := range iexceptions {
+			exception, ok := exception.(string)
+			if ok {
+				exceptions = append(exceptions, exception)
+			}
+		}
+	}
+	aexceptions, ok := config["exceptions"].([]string)
+	if ok {
+		exceptions = append(exceptions, aexceptions...)
+	}
+	if len(exceptions) == 0 {
+		return nil, fmt.Errorf("no pattern found in 'exception' property")
+	}
+	exceptionPattern := strings.Join(exceptions, "|")
+	r, err := regexp.Compile(exceptionPattern)
+	if err != nil {
+		return nil, fmt.Errorf("unable to build regexp tokenizer: %v", err)
+	}
+
+	remainingName, ok := config["tokenizer"].(string)
+	if !ok {
+		return nil, fmt.Errorf("must specify tokenizer for remaining input")
+	}
+	remaining, err := cache.TokenizerNamed(remainingName)
+	if err != nil {
+		return nil, err
+	}
+	return NewExceptionsTokenizer(r, remaining), nil
+}
+
+func init() {
+	err := registry.RegisterTokenizer(Name, ExceptionsTokenizerConstructor)
+	if err != nil {
+		panic(err)
+	}
+}