feat(types,blahd): allow using mock clock for testing

blahd/src/feed.rs

@@ -1,7 +1,7 @@
 //! Room feed generation.
 use std::fmt;
 use std::num::NonZero;
-use std::time::{Duration, SystemTime};
+use std::time::Duration;
 
 use axum::http::header;
 use axum::response::{IntoResponse, Response};
@@ -43,7 +43,8 @@ pub trait FeedType {
 }
 
 fn timestamp_to_rfc3339(timestamp: u64) -> impl fmt::Display {
-    humantime::format_rfc3339(SystemTime::UNIX_EPOCH + Duration::from_secs(timestamp))
+    // This only for formatting, thus always use the non-mock `SystemTime`.
+    humantime::format_rfc3339(std::time::SystemTime::UNIX_EPOCH + Duration::from_secs(timestamp))
 }
 
 /// See:

blahd/src/id.rs

@@ -1,10 +1,12 @@
+use std::cell::Cell;
+
 /// Id generation.
 /// Ref: https://en.wikipedia.org/wiki/Snowflake_ID
-/// FIXME: Currently we assume no more than one request in a single millisecond.
-use std::time::SystemTime;
-
+/// FIXME: Handle multi-threaded runtime.
 use blah_types::Id;
 
+use crate::utils::SystemTime;
+
 pub fn timestamp_of_id(id: Id) -> u64 {
     (id.0 as u64 >> 16) / 1000
 }
@@ -16,17 +18,32 @@ pub trait IdExt {
     fn is_peer_chat(&self) -> bool;
 }
 
+thread_local! {
+    static LAST_ID: Cell<i64> = const { Cell::new(0) };
+}
+
 impl IdExt for Id {
     fn gen() -> Self {
         let timestamp = SystemTime::now()
             .duration_since(SystemTime::UNIX_EPOCH)
             .expect("after UNIX epoch");
         let timestamp_ms = timestamp.as_millis();
-        assert!(
-            0 < timestamp_ms && timestamp_ms < (1 << 48),
-            "invalid timestamp",
-        );
-        Id((timestamp_ms as i64) << 16)
+        assert!(timestamp_ms < (1 << 48), "invalid timestamp");
+        let timestamp_ms = timestamp_ms as i64;
+        let id = timestamp_ms << 16;
+        LAST_ID.with(|last_id| {
+            let prev = last_id.get();
+            if prev >> 16 != timestamp_ms {
+                // If not in the same millisecond, use the new timestamp as id.
+                last_id.set(id);
+                Id(id)
+            } else {
+                // Otherwise, try to increse the trailing counter.
+                assert!(prev < (1 << 16), "id counter overflow");
+                last_id.set(prev + 1);
+                Id(prev + 1)
+            }
+        })
     }
 
     fn gen_peer_chat_rid() -> Self {

blahd/src/register.rs

@@ -1,5 +1,5 @@
 use std::num::NonZero;
-use std::time::{Duration, Instant};
+use std::time::Duration;
 
 use anyhow::{anyhow, ensure};
 use axum::http::{HeaderMap, HeaderName, StatusCode};
@@ -15,6 +15,7 @@ use serde::Deserialize;
 use sha2::{Digest, Sha256};
 
 use crate::database::TransactionOps;
+use crate::utils::Instant;
 use crate::{ApiError, AppState, SERVER_AND_VERSION};
 
 #[derive(Debug, Clone, PartialEq, Eq, Deserialize)]

blahd/src/utils.rs

@@ -1,6 +1,12 @@
 use std::collections::{HashSet, VecDeque};
 use std::hash::Hash;
-use std::time::{Duration, Instant};
+use std::time::Duration;
+
+#[cfg(not(feature = "unsafe_use_mock_instant_for_testing"))]
+pub use std::time::{Instant, SystemTime};
+
+#[cfg(feature = "unsafe_use_mock_instant_for_testing")]
+pub use mock_instant::thread_local::{Instant, SystemTime};
 
 #[derive(Debug)]
 pub struct ExpiringSet<T> {