make proper SessionId type

src/protocol.rs

@@ -29,7 +29,7 @@ pub struct AudioPacket {
 
     // stream id - set to the start time of a stream, used by receivers to
     // detect new stream starts, used by senders to detect stream takeovers
-    pub sid: TimestampMicros,
+    pub sid: SessionId,
 
     // packet sequence number - monotonic + gapless, arbitrary start point
     pub seq: u64,
@@ -50,7 +50,7 @@ pub struct AudioPacket {
 pub struct TimePacket {
     pub magic: u32,
     pub flags: u32,
-    pub sid: TimestampMicros,
+    pub sid: SessionId,
 
     pub stream_1: TimestampMicros,
     pub receive_2: TimestampMicros,
@@ -139,3 +139,16 @@ impl TimestampMicros {
         TimestampMicros(micros)
     }
 }
+
+#[derive(Debug, Clone, Copy, Zeroable, Pod, PartialEq, PartialOrd)]
+#[repr(transparent)]
+pub struct SessionId(i64);
+
+impl SessionId {
+    pub fn generate() -> Self {
+        let timespec = nix::time::clock_gettime(ClockId::CLOCK_REALTIME)
+            .expect("clock_gettime(CLOCK_REALTIME)");
+
+        SessionId(timespec.num_microseconds())
+    }
+}

src/receive.rs

@@ -8,7 +8,7 @@ use cpal::{SampleRate, OutputCallbackInfo};
 use cpal::traits::{HostTrait, DeviceTrait};
 use structopt::StructOpt;
 
-use crate::protocol::{AudioPacket, self, TimePacket, TimestampMicros, Packet};
+use crate::protocol::{AudioPacket, self, TimePacket, TimestampMicros, Packet, SessionId};
 use crate::resample::Resampler;
 use crate::status::{Status, StreamStatus};
 use crate::time::{Timestamp, SampleDuration, TimestampDelta, ClockDelta};
@@ -38,7 +38,7 @@ impl QueueEntry {
 }
 
 struct Stream {
-    sid: TimestampMicros,
+    sid: SessionId,
     start_seq: u64,
     sync: bool,
     resampler: Resampler,
@@ -97,7 +97,7 @@ impl Receiver {
             return;
         };
 
-        if stream.sid.0 != packet.sid.0 {
+        if stream.sid != packet.sid {
             // not relevant to our stream, ignore
             return;
         }
@@ -127,12 +127,12 @@ impl Receiver {
 
     fn prepare_stream(&mut self, packet: &AudioPacket) -> bool {
         if let Some(stream) = self.stream.as_mut() {
-            if packet.sid.0 < stream.sid.0 {
+            if packet.sid < stream.sid {
                 // packet belongs to a previous stream, ignore
                 return false;
             }
 
-            if packet.sid.0 > stream.sid.0 {
+            if packet.sid > stream.sid {
                 // new stream is taking over! switch over to it
                 println!("\nnew stream beginning");
                 self.stream = Some(Stream::start_from_packet(packet));

src/stream.rs

@@ -7,7 +7,7 @@ use cpal::traits::{HostTrait, DeviceTrait, StreamTrait};
 use cpal::InputCallbackInfo;
 use structopt::StructOpt;
 
-use crate::protocol::{self, Packet, TimestampMicros, AudioPacket, PacketBuffer, TimePacket, MAX_PACKET_SIZE, TimePacketPadding};
+use crate::protocol::{self, Packet, TimestampMicros, AudioPacket, PacketBuffer, TimePacket, MAX_PACKET_SIZE, TimePacketPadding, SessionId};
 use crate::time::{SampleDuration, Timestamp};
 use crate::util;
 use crate::RunError;
@@ -52,7 +52,7 @@ pub fn run(opt: StreamOpt) -> Result<(), RunError> {
     let delay = Duration::from_millis(opt.delay_ms);
     let delay = SampleDuration::from_std_duration_lossy(delay);
 
-    let sid = TimestampMicros::now();
+    let sid = SessionId::generate();
 
     let mut packet = AudioPacket {
         magic: protocol::MAGIC_AUDIO,
@@ -164,14 +164,14 @@ pub fn run(opt: StreamOpt) -> Result<(), RunError> {
             Some(Packet::Audio(packet)) => {
                 // we should only ever receive an audio packet if another
                 // stream is present. check if it should take over
-                if packet.sid.0 > sid.0 {
+                if packet.sid > sid {
                     eprintln!("Another stream has taken over from {addr}, exiting");
                     break;
                 }
             }
             Some(Packet::Time(packet)) => {
                 // only handle packet if it belongs to our stream:
-                if packet.sid.0 == sid.0 {
+                if packet.sid == sid {
                     packet.stream_3 = TimestampMicros::now();
                     socket.send_to(bytemuck::bytes_of(packet), addr)
                         .expect("socket.send responding to time packet");