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authorAlex Auvolat <alex@adnab.me>2022-06-29 15:52:09 +0200
committerAlex Auvolat <alex@adnab.me>2022-06-29 15:52:09 +0200
commitd737e33b5ac4a09ada10de70b78b866481d69cba (patch)
tree35570d745b126d5b29d7ebccba1204e0811da735 /src/mail/unique_ident.rs
parentb95028f89e4db7c3158fab3b71ea56a742daba21 (diff)
downloadaerogramme-d737e33b5ac4a09ada10de70b78b866481d69cba.tar.gz
aerogramme-d737e33b5ac4a09ada10de70b78b866481d69cba.zip
Rename MailIdent to UniqueIdent and use those to identify mailboxes
Diffstat (limited to 'src/mail/unique_ident.rs')
-rw-r--r--src/mail/unique_ident.rs95
1 files changed, 95 insertions, 0 deletions
diff --git a/src/mail/unique_ident.rs b/src/mail/unique_ident.rs
new file mode 100644
index 0000000..6046281
--- /dev/null
+++ b/src/mail/unique_ident.rs
@@ -0,0 +1,95 @@
+use std::str::FromStr;
+use std::sync::atomic::{AtomicU64, Ordering};
+
+use lazy_static::lazy_static;
+use rand::prelude::*;
+use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
+
+use crate::time::now_msec;
+
+/// An internal Mail Identifier is composed of two components:
+/// - a process identifier, 128 bits, itself composed of:
+/// - the timestamp of when the process started, 64 bits
+/// - a 64-bit random number
+/// - a sequence number, 64 bits
+/// They are not part of the protocol but an internal representation
+/// required by Mailrage/Aerogramme.
+/// Their main property is to be unique without having to rely
+/// on synchronization between IMAP processes.
+#[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug)]
+pub struct UniqueIdent(pub [u8; 24]);
+
+struct IdentGenerator {
+ pid: u128,
+ sn: AtomicU64,
+}
+
+impl IdentGenerator {
+ fn new() -> Self {
+ let time = now_msec() as u128;
+ let rand = thread_rng().gen::<u64>() as u128;
+ Self {
+ pid: (time << 64) | rand,
+ sn: AtomicU64::new(0),
+ }
+ }
+
+ fn gen(&self) -> UniqueIdent {
+ let sn = self.sn.fetch_add(1, Ordering::Relaxed);
+ let mut res = [0u8; 24];
+ res[0..16].copy_from_slice(&u128::to_be_bytes(self.pid));
+ res[16..24].copy_from_slice(&u64::to_be_bytes(sn));
+ UniqueIdent(res)
+ }
+}
+
+lazy_static! {
+ static ref GENERATOR: IdentGenerator = IdentGenerator::new();
+}
+
+pub fn gen_ident() -> UniqueIdent {
+ GENERATOR.gen()
+}
+
+// -- serde --
+
+impl<'de> Deserialize<'de> for UniqueIdent {
+ fn deserialize<D>(d: D) -> Result<Self, D::Error>
+ where
+ D: Deserializer<'de>,
+ {
+ let v = String::deserialize(d)?;
+ UniqueIdent::from_str(&v).map_err(D::Error::custom)
+ }
+}
+
+impl Serialize for UniqueIdent {
+ fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+ where
+ S: Serializer,
+ {
+ serializer.serialize_str(&self.to_string())
+ }
+}
+
+impl std::fmt::Display for UniqueIdent {
+ fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ write!(f, "{}", hex::encode(self.0))
+ }
+}
+
+impl FromStr for UniqueIdent {
+ type Err = &'static str;
+
+ fn from_str(s: &str) -> Result<UniqueIdent, &'static str> {
+ let bytes = hex::decode(s).map_err(|_| "invalid hex")?;
+
+ if bytes.len() != 24 {
+ return Err("bad length");
+ }
+
+ let mut tmp = [0u8; 24];
+ tmp[..].copy_from_slice(&bytes);
+ Ok(UniqueIdent(tmp))
+ }
+}