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filters.go
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filters.go
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/*
Package filters is a piece of thievery as the LDAP filter parsing code was
lifted serepticiously from
https://github.com/tonnerre/go-ldap/blob/master/ldap.go. The code was reused
this way as opposed to imports in order to modify it heavily for the needs of
the project.
*/
package filters
import (
"bytes"
"net/url"
"github.com/akutz/goof"
"github.com/codedellemc/rexray/libstorage/api/types"
)
const (
filterAnd = types.FilterAnd
filterOr = types.FilterOr
filterNot = types.FilterNot
filterPresent = types.FilterPresent
filterEqualityMatch = types.FilterEqualityMatch
filterSubstrings = types.FilterSubstrings
filterSubstringsPrefix = types.FilterSubstringsPrefix
filterSubstringsPostfix = types.FilterSubstringsPostfix
filterGreaterOrEqual = types.FilterGreaterOrEqual
filterLessOrEqual = types.FilterLessOrEqual
filterApproxMatch = types.FilterApproxMatch
)
var filterMap = map[types.FilterOperator]string{
filterAnd: "And",
filterOr: "Or",
filterNot: "Not",
filterEqualityMatch: "Equality Match",
filterSubstrings: "Substrings",
filterGreaterOrEqual: "Greater Or Equal",
filterLessOrEqual: "Less Or Equal",
filterPresent: "Present",
filterApproxMatch: "Approx Match",
}
var (
errCharZeroNotLParen = goof.New("filter does not start with an '()'")
errUnexpectedEOF = goof.New("unexpected end of filter")
errCompile = goof.New("error compiling filter")
errParse = goof.New("error parsing filter")
)
// CompileFilter compiles a filter string.
func CompileFilter(s string) (*types.Filter, error) {
es, err := url.QueryUnescape(s)
if err != nil {
return nil, err
}
s = es
if len(s) == 0 || s[0] != '(' {
return nil, errCharZeroNotLParen
}
f, pos, err := compileFilter(s, 1)
if err != nil {
return nil, err
}
if pos != len(s) {
return nil, goof.WithField(
"extra", s[pos:],
"finished compiling filter with extra at end")
}
return f, nil
}
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
}
}