server: Hand-implement Serialize

[tattlekey] / server / src / main.rs

diff --git a/server/src/main.rs b/server/src/main.rs
index 573edc580a8a99fc1671e37cb9cb90f6df108c88..500c2f55f9fba7296c4eb17d68be5a7d75e86e8b 100644 (file)
--- a/server/src/main.rs
+++ b/server/src/main.rs
@@ -14,15 +14,15 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-use serde::Serialize;
+use serde::ser::{Serialize, SerializeStruct, Serializer};
 use std::collections::HashMap;
 use std::net::UdpSocket;
-use std::time::{Duration, SystemTime};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 const MESSAGE_SIZE: usize = 12;
 const LOGFILENAME: &str = "log.csv";
 
-#[derive(Eq, Debug, Hash, PartialEq, Serialize)]
+#[derive(Eq, Debug, Hash, PartialEq)]
 struct MessageKey {
     epoch: u32,
     device: u16,
@@ -32,19 +32,37 @@ struct MessageKey {
 #[derive(Debug)]
 struct Message {
     key: MessageKey,
-    t: SystemTime,
+    t: u64,
+}
+impl Serialize for Message {
+    // https://github.com/BurntSushi/rust-csv/issues/155
+    // https://github.com/BurntSushi/rust-csv/issues/98
+    // https://github.com/BurntSushi/rust-csv/pull/223
+    // csv doesn't support #[serde(flatten)], so we implement this directly.  :(
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let mut row = serializer.serialize_struct("Message", 4)?;
+        row.serialize_field("epoch", &self.key.epoch)?;
+        row.serialize_field("device", &self.key.device)?;
+        row.serialize_field("seq", &self.key.seq)?;
+        row.serialize_field("t", &self.t)?;
+        row.end()
+    }
 }
 
 impl From<&[u8; MESSAGE_SIZE]> for Message {
     fn from(value: &[u8; MESSAGE_SIZE]) -> Self {
         let ago = u32::from_be_bytes(value[8..=11].try_into().expect("I can't count"));
+        let press_time = SystemTime::now() - Duration::new(ago.into(), 0);
         Self {
             key: MessageKey {
                 epoch: u32::from_be_bytes(value[0..=3].try_into().expect("I can't count")),
                 device: u16::from_be_bytes(value[4..=5].try_into().expect("I can't count")),
                 seq: u16::from_be_bytes(value[6..=7].try_into().expect("I can't count")),
             },
-            t: SystemTime::now() - Duration::new(ago.into(), 0),
+            t: press_time
+                .duration_since(UNIX_EPOCH)
+                .expect("Bad time?")
+                .as_secs(),
         }
     }
 }
@@ -60,17 +78,17 @@ impl TryFrom<&[u8]> for Message {
 
 #[derive(Debug)]
 struct Range {
-    start: SystemTime,
-    end: SystemTime,
+    start: u64,
+    end: u64,
 }
 impl Range {
-    fn new(t: &SystemTime) -> Self {
+    fn new(t: &u64) -> Self {
         Self { start: *t, end: *t }
     }
-    fn contains(&self, t: &SystemTime) -> bool {
+    fn contains(&self, t: &u64) -> bool {
         t > &self.start && t < &self.end
     }
-    fn extend(&mut self, t: &SystemTime) {
+    fn extend(&mut self, t: &u64) {
         if t < &self.start {
             self.start = *t;
         }
@@ -80,18 +98,32 @@ impl Range {
     }
 }
 
-fn main() {
+fn merge_message(presses: &mut HashMap<MessageKey, Range>, message: Message) {
+    if let Some(r) = presses.get_mut(&message.key) {
+        if !r.contains(&message.t) {
+            r.extend(&message.t);
+        }
+    } else {
+        presses.insert(message.key, Range::new(&message.t));
+    }
+}
+
+fn open_log_for_writing() -> csv::Writer<std::fs::File> {
     let log_file_exists = std::path::Path::new(LOGFILENAME).exists();
     let logfile = std::fs::OpenOptions::new()
         .create_new(!log_file_exists)
         .append(true)
         .open(LOGFILENAME)
         .expect("Coudln't open log file");
-    let mut log = csv::WriterBuilder::new()
+    csv::WriterBuilder::new()
         .has_headers(!log_file_exists)
-        .from_writer(logfile);
-    let mut presses = HashMap::<MessageKey, Range>::new();
+        .from_writer(logfile)
+}
+
+fn main() {
     let socket = UdpSocket::bind("0.0.0.0:29803").expect("couldn't bind to address");
+    let mut presses = HashMap::<MessageKey, Range>::new();
+    let mut log = open_log_for_writing();
     loop {
         let mut buf = [0; MESSAGE_SIZE];
         match socket.recv_from(&mut buf) {
@@ -103,16 +135,9 @@ fn main() {
                     continue;
                 }
                 let message = Message::try_from(filled_buf).expect("I can't count");
-                log.serialize((&message.key, message.t))
-                    .expect("Couldn't write log");
+                log.serialize(&message).expect("Couldn't write log");
                 log.flush().expect("Couldn't flush log");
-                if let Some(r) = presses.get_mut(&message.key) {
-                    if !r.contains(&message.t) {
-                        r.extend(&message.t);
-                    }
-                } else {
-                    presses.insert(message.key, Range::new(&message.t));
-                }
+                merge_message(&mut presses, message);
             }
         }
     }