diff options
Diffstat (limited to 'vendor/github.com/godbus/dbus/v5/decoder.go')
-rw-r--r-- | vendor/github.com/godbus/dbus/v5/decoder.go | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/vendor/github.com/godbus/dbus/v5/decoder.go b/vendor/github.com/godbus/dbus/v5/decoder.go new file mode 100644 index 000000000..ede91575b --- /dev/null +++ b/vendor/github.com/godbus/dbus/v5/decoder.go @@ -0,0 +1,286 @@ +package dbus + +import ( + "encoding/binary" + "io" + "reflect" +) + +type decoder struct { + in io.Reader + order binary.ByteOrder + pos int +} + +// newDecoder returns a new decoder that reads values from in. The input is +// expected to be in the given byte order. +func newDecoder(in io.Reader, order binary.ByteOrder) *decoder { + dec := new(decoder) + dec.in = in + dec.order = order + return dec +} + +// align aligns the input to the given boundary and panics on error. +func (dec *decoder) align(n int) { + if dec.pos%n != 0 { + newpos := (dec.pos + n - 1) & ^(n - 1) + empty := make([]byte, newpos-dec.pos) + if _, err := io.ReadFull(dec.in, empty); err != nil { + panic(err) + } + dec.pos = newpos + } +} + +// Calls binary.Read(dec.in, dec.order, v) and panics on read errors. +func (dec *decoder) binread(v interface{}) { + if err := binary.Read(dec.in, dec.order, v); err != nil { + panic(err) + } +} + +func (dec *decoder) Decode(sig Signature) (vs []interface{}, err error) { + defer func() { + var ok bool + v := recover() + if err, ok = v.(error); ok { + if err == io.EOF || err == io.ErrUnexpectedEOF { + err = FormatError("unexpected EOF") + } + } + }() + vs = make([]interface{}, 0) + s := sig.str + for s != "" { + err, rem := validSingle(s, 0) + if err != nil { + return nil, err + } + v := dec.decode(s[:len(s)-len(rem)], 0) + vs = append(vs, v) + s = rem + } + return vs, nil +} + +func (dec *decoder) decode(s string, depth int) interface{} { + dec.align(alignment(typeFor(s))) + switch s[0] { + case 'y': + var b [1]byte + if _, err := dec.in.Read(b[:]); err != nil { + panic(err) + } + dec.pos++ + return b[0] + case 'b': + i := dec.decode("u", depth).(uint32) + switch { + case i == 0: + return false + case i == 1: + return true + default: + panic(FormatError("invalid value for boolean")) + } + case 'n': + var i int16 + dec.binread(&i) + dec.pos += 2 + return i + case 'i': + var i int32 + dec.binread(&i) + dec.pos += 4 + return i + case 'x': + var i int64 + dec.binread(&i) + dec.pos += 8 + return i + case 'q': + var i uint16 + dec.binread(&i) + dec.pos += 2 + return i + case 'u': + var i uint32 + dec.binread(&i) + dec.pos += 4 + return i + case 't': + var i uint64 + dec.binread(&i) + dec.pos += 8 + return i + case 'd': + var f float64 + dec.binread(&f) + dec.pos += 8 + return f + case 's': + length := dec.decode("u", depth).(uint32) + b := make([]byte, int(length)+1) + if _, err := io.ReadFull(dec.in, b); err != nil { + panic(err) + } + dec.pos += int(length) + 1 + return string(b[:len(b)-1]) + case 'o': + return ObjectPath(dec.decode("s", depth).(string)) + case 'g': + length := dec.decode("y", depth).(byte) + b := make([]byte, int(length)+1) + if _, err := io.ReadFull(dec.in, b); err != nil { + panic(err) + } + dec.pos += int(length) + 1 + sig, err := ParseSignature(string(b[:len(b)-1])) + if err != nil { + panic(err) + } + return sig + case 'v': + if depth >= 64 { + panic(FormatError("input exceeds container depth limit")) + } + var variant Variant + sig := dec.decode("g", depth).(Signature) + if len(sig.str) == 0 { + panic(FormatError("variant signature is empty")) + } + err, rem := validSingle(sig.str, 0) + if err != nil { + panic(err) + } + if rem != "" { + panic(FormatError("variant signature has multiple types")) + } + variant.sig = sig + variant.value = dec.decode(sig.str, depth+1) + return variant + case 'h': + return UnixFDIndex(dec.decode("u", depth).(uint32)) + case 'a': + if len(s) > 1 && s[1] == '{' { + ksig := s[2:3] + vsig := s[3 : len(s)-1] + v := reflect.MakeMap(reflect.MapOf(typeFor(ksig), typeFor(vsig))) + if depth >= 63 { + panic(FormatError("input exceeds container depth limit")) + } + length := dec.decode("u", depth).(uint32) + // Even for empty maps, the correct padding must be included + dec.align(8) + spos := dec.pos + for dec.pos < spos+int(length) { + dec.align(8) + if !isKeyType(v.Type().Key()) { + panic(InvalidTypeError{v.Type()}) + } + kv := dec.decode(ksig, depth+2) + vv := dec.decode(vsig, depth+2) + v.SetMapIndex(reflect.ValueOf(kv), reflect.ValueOf(vv)) + } + return v.Interface() + } + if depth >= 64 { + panic(FormatError("input exceeds container depth limit")) + } + sig := s[1:] + length := dec.decode("u", depth).(uint32) + // capacity can be determined only for fixed-size element types + var capacity int + if s := sigByteSize(sig); s != 0 { + capacity = int(length) / s + } + v := reflect.MakeSlice(reflect.SliceOf(typeFor(sig)), 0, capacity) + // Even for empty arrays, the correct padding must be included + align := alignment(typeFor(s[1:])) + if len(s) > 1 && s[1] == '(' { + //Special case for arrays of structs + //structs decode as a slice of interface{} values + //but the dbus alignment does not match this + align = 8 + } + dec.align(align) + spos := dec.pos + for dec.pos < spos+int(length) { + ev := dec.decode(s[1:], depth+1) + v = reflect.Append(v, reflect.ValueOf(ev)) + } + return v.Interface() + case '(': + if depth >= 64 { + panic(FormatError("input exceeds container depth limit")) + } + dec.align(8) + v := make([]interface{}, 0) + s = s[1 : len(s)-1] + for s != "" { + err, rem := validSingle(s, 0) + if err != nil { + panic(err) + } + ev := dec.decode(s[:len(s)-len(rem)], depth+1) + v = append(v, ev) + s = rem + } + return v + default: + panic(SignatureError{Sig: s}) + } +} + +// sigByteSize tries to calculates size of the given signature in bytes. +// +// It returns zero when it can't, for example when it contains non-fixed size +// types such as strings, maps and arrays that require reading of the transmitted +// data, for that we would need to implement the unread method for Decoder first. +func sigByteSize(sig string) int { + var total int + for offset := 0; offset < len(sig); { + switch sig[offset] { + case 'y': + total += 1 + offset += 1 + case 'n', 'q': + total += 2 + offset += 1 + case 'b', 'i', 'u', 'h': + total += 4 + offset += 1 + case 'x', 't', 'd': + total += 8 + offset += 1 + case '(': + i := 1 + depth := 1 + for i < len(sig[offset:]) && depth != 0 { + if sig[offset+i] == '(' { + depth++ + } else if sig[offset+i] == ')' { + depth-- + } + i++ + } + s := sigByteSize(sig[offset+1 : offset+i-1]) + if s == 0 { + return 0 + } + total += s + offset += i + default: + return 0 + } + } + return total +} + +// A FormatError is an error in the wire format. +type FormatError string + +func (e FormatError) Error() string { + return "dbus: wire format error: " + string(e) +} |