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filters: supporting alternative characters for quote

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The regexp syntax can have some nasty characters to handle quoting
correctly, in practice. In certain scenarios a double quote works well,
but it can affect readability for certain regexps. This introduces a
quoting mode that treats `/` and `|` as a double quote to make the
quoting in regular expressions more familiar and readable.

This change is introduced in a backwards compatible manner, so existing
regexp quoting is not affected.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
This commit is contained in:
Stephen J Day
2017-12-04 17:12:41 -08:00
parent 617c63de06
commit 4dfcf60bec
5 changed files with 343 additions and 11 deletions
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22
filters/parser.go
View File

@@ -3,7 +3,6 @@ package filters
import (
"fmt"
"io"
"strconv"
"github.com/containerd/containerd/errdefs"
"github.com/pkg/errors"
@@ -134,7 +133,12 @@ func (p *parser) selector() (selector, error) {
return selector{}, err
}
value, err := p.value()
var allowAltQuotes bool
if op == operatorMatches {
allowAltQuotes = true
}
value, err := p.value(allowAltQuotes)
if err != nil {
if err == io.EOF {
return selector{}, io.ErrUnexpectedEOF
@@ -188,7 +192,7 @@ func (p *parser) field() (string, error) {
case tokenField:
return s, nil
case tokenQuoted:
return p.unquote(pos, s)
return p.unquote(pos, s, false)
}
return "", p.mkerr(pos, "expected field or quoted")
@@ -213,21 +217,25 @@ func (p *parser) operator() (operator, error) {
return 0, p.mkerr(pos, `expected an operator ("=="|"!="|"~=")`)
}
func (p *parser) value() (string, error) {
func (p *parser) value(allowAltQuotes bool) (string, error) {
pos, tok, s := p.scanner.scan()
switch tok {
case tokenValue, tokenField:
return s, nil
case tokenQuoted:
return p.unquote(pos, s)
return p.unquote(pos, s, allowAltQuotes)
}
return "", p.mkerr(pos, "expected value or quoted")
}
func (p *parser) unquote(pos int, s string) (string, error) {
uq, err := strconv.Unquote(s)
func (p *parser) unquote(pos int, s string, allowAlts bool) (string, error) {
if !allowAlts && s[0] != '\'' && s[0] != '"' {
return "", p.mkerr(pos, "invalid quote encountered")
}
uq, err := unquote(s)
if err != nil {
return "", p.mkerr(pos, "unquoting failed: %v", err)
}