func compileFilterSet(
s string, pos int, parent *types.Filter) (int, error) {
for pos < len(s) && s[pos] == '(' {
child, newPos, err := compileFilter(s, pos+1)
if err != nil {
return pos, err
}
pos = newPos
parent.Children = append(parent.Children, child)
}
if pos == len(s) {
return pos, errUnexpectedEOF
}
return pos + 1, nil
}
func compileFilter(s string, pos int) (*types.Filter, int, error) {
switch s[pos] {
case '(':
f, newPos, err := compileFilter(s, pos+1)
newPos++
return f, newPos, err
case '&':
f := &types.Filter{Op: filterAnd}
newPos, err := compileFilterSet(s, pos+1, f)
return f, newPos, err
case '|':
f := &types.Filter{Op: filterOr}
newPos, err := compileFilterSet(s, pos+1, f)
return f, newPos, err
case '!':
f := &types.Filter{Op: filterNot}
child, newPos, err := compileFilter(s, pos+1)
f.Children = append(f.Children, child)
return f, newPos, err
default:
var (
f *types.Filter
abuf, cbuf bytes.Buffer
newPos = pos
)
for newPos < len(s) && s[newPos] != ')' {
switch {
case f != nil:
if err := cbuf.WriteByte(s[newPos]); err != nil {
return nil, 0, err
}
case s[newPos] == '=':
f = &types.Filter{Op: filterEqualityMatch}
case s[newPos] == '>' && s[newPos+1] == '=':
f = &types.Filter{Op: filterGreaterOrEqual}
newPos++
case s[newPos] == '<' && s[newPos+1] == '=':
f = &types.Filter{Op: filterLessOrEqual}
newPos++
case s[newPos] == '~' && s[newPos+1] == '=':
f = &types.Filter{Op: filterApproxMatch}
newPos++
case f == nil:
if err := abuf.WriteByte(s[newPos]); err != nil {
return nil, 0, err
}
}
newPos++
}
if newPos == len(s) {
return f, newPos, errUnexpectedEOF
}
if f == nil {
return nil, 0, errParse
}
f.Left = abuf.String()
var (
cbyt = cbuf.Bytes()
cstr = cbuf.String()
clen = len(cbyt)
cfch = cbyt[clen-1]
)
switch {
case f.Op == filterEqualityMatch && cstr == "*":
f.Op = filterPresent
case f.Op == filterEqualityMatch &&
cbyt[0] == '*' && cfch == '*' && clen > 2:
f.Op = filterSubstrings
f.Right = cstr[1 : clen-1]
case f.Op == filterEqualityMatch && cbyt[0] == '*' && clen > 1:
f.Op = filterSubstringsPrefix
f.Right = cstr[1:]
case f.Op == filterEqualityMatch && cfch == '*' && clen > 1:
f.Op = filterSubstringsPostfix
f.Right = cstr[:clen-1]
default:
f.Right = cstr
}
newPos++
return f, newPos, nil
}
}
