db: share one now_f64() instead of four private copies

handlers, queue, send and link_cache each carried the same SystemTime
helper; a single crate::db::now_f64() removes the drift risk.

crates/xmedia-bot/src/db.rs

@@ -19,6 +19,15 @@ pub fn open_db(path: &str) -> rusqlite::Result<Connection> {
     Ok(conn)
 }
 
+/// Unix timestamp in fractional seconds. Shared by the queue, chat store and
+/// link cache (previously four private copies).
+pub fn now_f64() -> f64 {
+    std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .map(|d| d.as_secs_f64())
+        .unwrap_or(0.0)
+}
+
 /// Runs `f` against a fresh connection on a blocking thread, returning the
 /// closure's result. Owns the `spawn_blocking` + `expect` ceremony shared by
 /// every table access; the caller maps errors to its own log line.

crates/xmedia-bot/src/handlers.rs

@@ -1,4 +1,5 @@
 use crate::config::Config;
+use crate::db::now_f64;
 use crate::link_cache::{CachedMediaKind, CachedPost, LinkCache};
 use crate::queue::PersistentTaskQueue;
 use crate::send::{self, MediaItemPayload, Task};
@@ -111,13 +112,6 @@ where
         .await
 }
 
-fn now_f64() -> f64 {
-    std::time::SystemTime::now()
-        .duration_since(std::time::UNIX_EPOCH)
-        .map(|d| d.as_secs_f64())
-        .unwrap_or(0.0)
-}
-
 /// Extracts URL and text-link entities (text + caption), deduped in order.
 pub fn extract_urls(message: &Message) -> Vec<String> {
     let mut urls = Vec::new();

crates/xmedia-bot/src/link_cache.rs

@@ -8,6 +8,7 @@
 //! [`Config::link_cache_ttl`]; a stale entry is dropped lazily on read and
 //! by the periodic prune in `main`.
 
+use crate::db::now_f64;
 use rusqlite::{Connection, params};
 use serde::{Deserialize, Serialize};
 use std::time::Duration;
@@ -163,13 +164,6 @@ impl LinkCache {
     }
 }
 
-fn now_f64() -> f64 {
-    std::time::SystemTime::now()
-        .duration_since(std::time::UNIX_EPOCH)
-        .map(|d| d.as_secs_f64())
-        .unwrap_or(0.0)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

crates/xmedia-bot/src/queue.rs

@@ -5,13 +5,14 @@
 //! flow. The Python dict-mutation hack (attempts inside the payload) is
 //! replaced by dedicated columns.
 
+use crate::db::now_f64;
 use parking_lot::Mutex;
 use rusqlite::{Connection, TransactionBehavior, params};
 use serde_json::Value;
 use std::pin::Pin;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
-use std::time::{Duration, SystemTime, UNIX_EPOCH};
+use std::time::Duration;
 use tokio::sync::Notify;
 use tokio::task::JoinHandle;
 
@@ -62,13 +63,6 @@ struct QueueWorker {
     dead_letter: Arc<DeadLetter>,
 }
 
-fn now_f64() -> f64 {
-    SystemTime::now()
-        .duration_since(UNIX_EPOCH)
-        .map(|d| d.as_secs_f64())
-        .unwrap_or(0.0)
-}
-
 /// Resets rows left `in_progress` with an expired lock TTL back to `pending`
 /// so they can be leased again (crash/panic recovery).
 fn recover_update(conn: &rusqlite::Connection) -> rusqlite::Result<()> {