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use crate::{DecodeError, Value, BUS_NAMES, INTERFACE_REGEX, MEMBER_REGEX, OBJECT_PATH_REGEX};
use std::convert::TryFrom;
/// An enum representing a [header field].
///
/// [header field]: https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-header-fields
#[derive(Debug, Clone, PartialOrd, PartialEq, Ord, Eq)]
pub enum Header {
Path(String),
Interface(String),
Member(String),
ErrorName(String),
ReplySerial(u32),
Destination(String),
Sender(String),
Signature(String),
}
impl TryFrom<Value> for Header {
type Error = DecodeError;
fn try_from(v: Value) -> Result<Self, Self::Error> {
// The outer `Value` has to be a struct.
if let Value::Struct(mut values) = v {
// The length of the struct have to be 2
if values.len() == 2 {
// Check if the second is a Variant and unwrap the value.
let v = if let Value::Variant(mut v) = values.pop().unwrap() {
// The Variant should only contain one element.
if v.len() != 1 {
return Err(DecodeError::Header);
}
v.pop().unwrap()
} else {
return Err(DecodeError::Header);
};
// Check if the first is a byte
if let Value::Byte(b) = values.pop().unwrap() {
match b {
1 => {
// The header field is a Path.
if let Value::ObjectPath(s) = v {
if OBJECT_PATH_REGEX.is_match(&s) {
Ok(Header::Path(s))
} else {
Err(DecodeError::ObjectPathRegex)
}
} else {
Err(DecodeError::Header)
}
}
2 => {
// The header field is an Interface.
if let Value::String(s) = v {
if INTERFACE_REGEX.is_match(&s) {
Ok(Header::Interface(s))
} else {
Err(DecodeError::InterfaceRegex)
}
} else {
Err(DecodeError::Header)
}
}
3 => {
// The header field is an Member.
if let Value::String(s) = v {
if MEMBER_REGEX.is_match(&s) {
Ok(Header::Member(s))
} else {
Err(DecodeError::MemberRegex)
}
} else {
Err(DecodeError::Header)
}
}
4 => {
// The header field is an ErrorName.
if let Value::String(s) = v {
Ok(Header::ErrorName(s))
} else {
Err(DecodeError::Header)
}
}
5 => {
// The header field is a ReplySerial.
if let Value::Uint32(u) = v {
Ok(Header::ReplySerial(u))
} else {
Err(DecodeError::Header)
}
}
6 => {
// The header field is a Destination.
if let Value::String(s) = v {
if BUS_NAMES.is_match(&s) {
Ok(Header::Destination(s))
} else {
Err(DecodeError::BusNamesRegex)
}
} else {
Err(DecodeError::Header)
}
}
7 => {
// The header field is a Sender.
if let Value::String(s) = v {
if BUS_NAMES.is_match(&s) {
Ok(Header::Sender(s))
} else {
Err(DecodeError::BusNamesRegex)
}
} else {
Err(DecodeError::Header)
}
}
8 => {
// The header field is a Signature.
if let Value::Signature(s) = v {
Ok(Header::Signature(s))
} else {
Err(DecodeError::Header)
}
}
_ => {
// Invalid number.
Err(DecodeError::Header)
}
}
} else {
Err(DecodeError::Header)
}
} else {
Err(DecodeError::Header)
}
} else {
Err(DecodeError::Header)
}
}
}