Add ServiceFlags type

src/network/constants.rs

@@ -37,6 +37,10 @@
 //! assert_eq!(&bytes[..], &[0xF9, 0xBE, 0xB4, 0xD9]);
 //! ```
 
+use std::{io, ops};
+
+use consensus::encode::{self, Encodable, Decodable};
+
 /// Version of the protocol as appearing in network message headers
 pub const PROTOCOL_VERSION: u32 = 70001;
 /// Bitfield of services provided by this node
@@ -99,9 +103,125 @@ impl Network {
     }
 }
 
+/// Flags to indicate which network services a node supports.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ServiceFlags(u64);
+
+impl ServiceFlags {
+    /// NONE means no services supported.
+    pub const NONE: ServiceFlags = ServiceFlags(0);
+
+    /// NETWORK means that the node is capable of serving the complete block chain. It is currently
+    /// set by all Bitcoin Core non pruned nodes, and is unset by SPV clients or other light
+    /// clients.
+    pub const NETWORK: ServiceFlags = ServiceFlags(1 << 0);
+
+    /// GETUTXO means the node is capable of responding to the getutxo protocol request.  Bitcoin
+    /// Core does not support this but a patch set called Bitcoin XT does.
+    /// See BIP 64 for details on how this is implemented.
+    pub const GETUTXO: ServiceFlags = ServiceFlags(1 << 1);
+
+    /// BLOOM means the node is capable and willing to handle bloom-filtered connections.  Bitcoin
+    /// Core nodes used to support this by default, without advertising this bit, but no longer do
+    /// as of protocol version 70011 (= NO_BLOOM_VERSION)
+    pub const BLOOM: ServiceFlags = ServiceFlags(1 << 2);
+
+    /// WITNESS indicates that a node can be asked for blocks and transactions including witness
+    /// data.
+    pub const WITNESS: ServiceFlags = ServiceFlags(1 << 3);
+
+    /// NETWORK_LIMITED means the same as NODE_NETWORK with the limitation of only serving the last
+    /// 288 (2 day) blocks.
+    /// See BIP159 for details on how this is implemented.
+    pub const NETWORK_LIMITED: ServiceFlags = ServiceFlags(1 << 10);
+
+    /// Add [ServiceFlags] together.
+    ///
+    /// Returns itself.
+    pub fn add(&mut self, other: ServiceFlags) -> ServiceFlags {
+        self.0 |= other.0;
+        *self
+    }
+
+    /// Remove [ServiceFlags] from this.
+    ///
+    /// Returns itself.
+    pub fn remove(&mut self, other: ServiceFlags) -> ServiceFlags {
+        self.0 ^= other.0;
+        *self
+    }
+
+    /// Check whether [ServiceFlags] are included in this one.
+    pub fn has(&self, flags: ServiceFlags) -> bool {
+        (self.0 | flags.0) == self.0
+    }
+
+    /// Get the integer representation of this [ServiceFlags].
+    pub fn as_u64(&self) -> u64 {
+        self.0
+    }
+}
+
+impl From<u64> for ServiceFlags {
+    fn from(f: u64) -> Self {
+        ServiceFlags(f)
+    }
+}
+
+impl Into<u64> for ServiceFlags {
+    fn into(self) -> u64 {
+        self.0
+    }
+}
+
+impl ops::BitOr for ServiceFlags {
+    type Output = Self;
+
+    fn bitor(mut self, rhs: Self) -> Self {
+        self.add(rhs)
+    }
+}
+
+impl ops::BitOrAssign for ServiceFlags {
+    fn bitor_assign(&mut self, rhs: Self) {
+        self.add(rhs);
+    }
+}
+
+impl ops::BitXor for ServiceFlags {
+    type Output = Self;
+
+    fn bitxor(mut self, rhs: Self) -> Self {
+        self.remove(rhs)
+    }
+}
+
+impl ops::BitXorAssign for ServiceFlags {
+    fn bitxor_assign(&mut self, rhs: Self) {
+        self.remove(rhs);
+    }
+}
+
+impl Encodable for ServiceFlags {
+    #[inline]
+    fn consensus_encode<S: io::Write>(
+        &self,
+        mut s: S,
+    ) -> Result<usize, encode::Error> {
+        self.0.consensus_encode(&mut s)
+    }
+}
+
+impl Decodable for ServiceFlags {
+    #[inline]
+    fn consensus_decode<D: io::Read>(mut d: D) -> Result<Self, encode::Error> {
+        Ok(ServiceFlags(Decodable::consensus_decode(&mut d)?))
+    }
+}
+
 #[cfg(test)]
 mod tests {
-    use super::Network;
+    use super::{Network, ServiceFlags};
     use consensus::encode::{deserialize, serialize};
 
     #[test]
@@ -144,5 +264,32 @@ mod tests {
         assert_eq!("regtest".parse::<Network>().unwrap(), Network::Regtest);
         assert!("fakenet".parse::<Network>().is_err());
     }
+
+    #[test]
+    fn service_flags_test() {
+        let all = [
+            ServiceFlags::NETWORK,
+            ServiceFlags::GETUTXO,
+            ServiceFlags::BLOOM,
+            ServiceFlags::WITNESS,
+            ServiceFlags::NETWORK_LIMITED,
+        ];
+
+        let mut flags = ServiceFlags::NONE;
+        for f in all.iter() {
+            assert!(!flags.has(*f));
+        }
+
+        flags |= ServiceFlags::WITNESS;
+        assert_eq!(flags, ServiceFlags::WITNESS);
+
+        let mut flags2 = flags | ServiceFlags::GETUTXO;
+        for f in all.iter() {
+            assert_eq!(flags2.has(*f), *f == ServiceFlags::WITNESS || *f == ServiceFlags::GETUTXO);
+        }
+
+        flags2 ^= ServiceFlags::WITNESS;
+        assert_eq!(flags2, ServiceFlags::GETUTXO);
+    }
 }