f8d3d9f0cf
Some checks failed
Coverage / coverage (push) Failing after 6s
Tests / test (1.24.x, ubuntu-latest) (push) Failing after 42s
Tests / test (1.26.x, ubuntu-latest) (push) Failing after 38s
Tests / test (1.25.x, ubuntu-latest) (push) Failing after 35s
Tests / test (1.25.x, windows-latest) (push) Has been cancelled
Tests / test (1.26.x, macos-latest) (push) Has been cancelled
Tests / test (1.26.x, windows-latest) (push) Has been cancelled
Tests / test (1.24.x, macos-latest) (push) Has been cancelled
Tests / test (1.24.x, windows-latest) (push) Has been cancelled
Tests / test (1.25.x, macos-latest) (push) Has been cancelled
64 lines
1.7 KiB
Go
64 lines
1.7 KiB
Go
// Copyright (c) 2020 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 scorch
|
|
|
|
import (
|
|
"regexp/syntax"
|
|
|
|
"github.com/blevesearch/vellum/regexp"
|
|
)
|
|
|
|
func parseRegexp(pattern string) (a *regexp.Regexp, prefixBeg, prefixEnd []byte, err error) {
|
|
// TODO: potential optimization where syntax.Regexp supports a Simplify() API?
|
|
|
|
parsed, err := syntax.Parse(pattern, syntax.Perl)
|
|
if err != nil {
|
|
return nil, nil, nil, err
|
|
}
|
|
|
|
re, err := regexp.NewParsedWithLimit(pattern, parsed, regexp.DefaultLimit)
|
|
if err != nil {
|
|
return nil, nil, nil, err
|
|
}
|
|
|
|
prefix := literalPrefix(parsed)
|
|
if prefix != "" {
|
|
prefixBeg := []byte(prefix)
|
|
prefixEnd := calculateExclusiveEndFromPrefix(prefixBeg)
|
|
return re, prefixBeg, prefixEnd, nil
|
|
}
|
|
|
|
return re, nil, nil, nil
|
|
}
|
|
|
|
// Returns the literal prefix given the parse tree for a regexp
|
|
func literalPrefix(s *syntax.Regexp) string {
|
|
// traverse the left-most branch in the parse tree as long as the
|
|
// node represents a concatenation
|
|
for s != nil && s.Op == syntax.OpConcat {
|
|
if len(s.Sub) < 1 {
|
|
return ""
|
|
}
|
|
|
|
s = s.Sub[0]
|
|
}
|
|
|
|
if s.Op == syntax.OpLiteral && (s.Flags&syntax.FoldCase == 0) {
|
|
return string(s.Rune)
|
|
}
|
|
|
|
return "" // no literal prefix
|
|
}
|