Add new ChannelId type; unused

diff --git a/lightning/src/ln/channel_id.rs b/lightning/src/ln/channel_id.rs
new file mode 100644 (file)
index 0000000..332fc35
--- /dev/null
+++ b/lightning/src/ln/channel_id.rs
@@ -0,0 +1,141 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+//! ChannelId definition.
+
+use crate::ln::msgs::DecodeError;
+use crate::sign::EntropySource;
+use crate::util::ser::{Readable, Writeable, Writer};
+
+use bitcoin::hashes::hex::ToHex;
+
+use crate::io;
+use crate::prelude::*;
+use core::fmt;
+use core::ops::Deref;
+
+/// A unique 32-byte identifier for a channel.
+/// Depending on how the ID is generated, several varieties are distinguished (but all are stored as 32 bytes): _v1_ and _temporary_.
+/// A _v1_ channel ID is generated based on funding tx outpoint (txid & index).
+/// A _temporary_ ID is generated randomly.
+/// (Later revocation-point-based _v2_ is a possibility.)
+/// The variety (context) is not stored, it is relevant only at creation.
+///
+/// This is not exported to bindings users as we just use [u8; 32] directly.
+#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+pub struct ChannelId (pub [u8; 32]);
+
+impl ChannelId {
+       /// Create _v1_ channel ID based on a funding TX ID and output index
+       pub fn v1_from_funding_txid(txid: &[u8; 32], output_index: u16) -> Self {
+               let mut res = [0; 32];
+               res[..].copy_from_slice(&txid[..]);
+               res[30] ^= ((output_index >> 8) & 0xff) as u8;
+               res[31] ^= ((output_index >> 0) & 0xff) as u8;
+               Self(res)
+       }
+
+       /// Create a _temporary_ channel ID randomly, based on an entropy source.
+       pub fn temporary_from_entropy_source<ES: Deref>(entropy_source: &ES) -> Self
+       where ES::Target: EntropySource {
+               Self(entropy_source.get_secure_random_bytes())
+       }
+
+       /// Generic constructor; create a new channel ID from the provided data.
+       /// Use a more specific `*_from_*` constructor when possible.
+       pub fn from_bytes(data: [u8; 32]) -> Self {
+               Self(data)
+       }
+
+       /// Create a channel ID consisting of all-zeros data (e.g. when uninitialized or a placeholder).
+       pub fn new_zero() -> Self {
+               Self([0; 32])
+       }
+
+       /// Check whether ID is consisting of all zeros (uninitialized)
+       pub fn is_zero(&self) -> bool {
+               self.0[..] == [0; 32]
+       }
+}
+
+impl Writeable for ChannelId {
+       fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
+               self.0.write(w)
+       }
+}
+
+impl Readable for ChannelId {
+       fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+               let buf: [u8; 32] = Readable::read(r)?;
+               Ok(ChannelId(buf))
+       }
+}
+
+impl ToHex for ChannelId {
+       fn to_hex(&self) -> String {
+               self.0.to_hex()
+       }
+}
+
+impl fmt::Display for ChannelId {
+       fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+               crate::util::logger::DebugBytes(&self.0).fmt(f)
+       }
+}
+
+#[cfg(test)]
+mod tests {
+       use crate::ln::ChannelId;
+       use crate::util::ser::{Readable, Writeable};
+       use crate::util::test_utils;
+       use bitcoin::hashes::hex::ToHex;
+       use crate::prelude::*;
+       use crate::io;
+
+       #[test]
+       fn test_channel_id_v1_from_funding_txid() {
+               let channel_id = ChannelId::v1_from_funding_txid(&[2; 32], 1);
+               assert_eq!(channel_id.to_hex(), "0202020202020202020202020202020202020202020202020202020202020203");
+       }
+
+       #[test]
+       fn test_channel_id_new_from_data() {
+               let data: [u8; 32] = [2; 32];
+               let channel_id = ChannelId::from_bytes(data.clone());
+               assert_eq!(channel_id.0, data);
+       }
+
+       #[test]
+       fn test_channel_id_equals() {
+               let channel_id11 = ChannelId::v1_from_funding_txid(&[2; 32], 2);
+               let channel_id12 = ChannelId::v1_from_funding_txid(&[2; 32], 2);
+               let channel_id21 = ChannelId::v1_from_funding_txid(&[2; 32], 42);
+               assert_eq!(channel_id11, channel_id12);
+               assert_ne!(channel_id11, channel_id21);
+       }
+
+       #[test]
+       fn test_channel_id_write_read() {
+               let data: [u8; 32] = [2; 32];
+               let channel_id = ChannelId::from_bytes(data.clone());
+
+               let mut w = test_utils::TestVecWriter(Vec::new());
+               channel_id.write(&mut w).unwrap();
+
+               let channel_id_2 = ChannelId::read(&mut io::Cursor::new(&w.0)).unwrap();
+               assert_eq!(channel_id_2, channel_id);
+               assert_eq!(channel_id_2.0, data);
+       }
+
+       #[test]
+       fn test_channel_id_display() {
+               let channel_id = ChannelId::v1_from_funding_txid(&[2; 32], 1);
+               assert_eq!(format!("{}", &channel_id), "0202020202020202020202020202020202020202020202020202020202020203");
+       }
+}

diff --git a/lightning/src/ln/mod.rs b/lightning/src/ln/mod.rs
index a5de0d4c2f5d77a70d254cca647808c77563ac50..bacb9e86c791bf61dee44246751c4f85c0e0f366 100644 (file)
--- a/lightning/src/ln/mod.rs
+++ b/lightning/src/ln/mod.rs
@@ -13,6 +13,7 @@
 #[macro_use]
 pub mod functional_test_utils;
 
+pub mod channel_id;
 pub mod channelmanager;
 pub mod inbound_payment;
 pub mod msgs;
@@ -31,6 +32,9 @@ pub mod channel;
 #[cfg(not(fuzzing))]
 pub(crate) mod channel;
 
+// Re-export ChannelId
+pub use self::channel_id::ChannelId;
+
 pub(crate) mod onion_utils;
 mod outbound_payment;
 pub mod wire;