Port Clock functions to use Duration class (#19229)

This changes the arguments in clock functions to be `Duration` and
converts call sites and constants into `Duration`. There are still some
more functions around that should be converted (e.g.
`timeout_deferred`), but we leave that to another PR.

We also changes `.as_secs()` to return a float, as the rounding broke
things subtly. The only reason to keep it (its the same as
`timedelta.total_seconds()`) is for symmetry with `as_millis()`.

Follows on from https://github.com/element-hq/synapse/pull/19223

rust/src/duration.rs

@@ -0,0 +1,56 @@
+/*
+ * This file is licensed under the Affero General Public License (AGPL) version 3.
+ *
+ * Copyright (C) 2025 Element Creations, Ltd
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * See the GNU Affero General Public License for more details:
+ * <https://www.gnu.org/licenses/agpl-3.0.html>.
+ */
+
+use once_cell::sync::OnceCell;
+use pyo3::{
+    types::{IntoPyDict, PyAnyMethods},
+    Bound, BoundObject, IntoPyObject, Py, PyAny, PyErr, PyResult, Python,
+};
+
+/// A reference to the `synapse.util.duration` module.
+static DURATION: OnceCell<Py<PyAny>> = OnceCell::new();
+
+/// Access to the `synapse.util.duration` module.
+fn duration_module(py: Python<'_>) -> PyResult<&Bound<'_, PyAny>> {
+    Ok(DURATION
+        .get_or_try_init(|| py.import("synapse.util.duration").map(Into::into))?
+        .bind(py))
+}
+
+/// Mirrors the `synapse.util.duration.Duration` Python class.
+pub struct SynapseDuration {
+    microseconds: u64,
+}
+
+impl SynapseDuration {
+    /// For now we only need to create durations from milliseconds.
+    pub fn from_milliseconds(milliseconds: u64) -> Self {
+        Self {
+            microseconds: milliseconds * 1_000,
+        }
+    }
+}
+
+impl<'py> IntoPyObject<'py> for &SynapseDuration {
+    type Target = PyAny;
+    type Output = Bound<'py, Self::Target>;
+    type Error = PyErr;
+
+    fn into_pyobject(self, py: Python<'py>) -> Result<Self::Output, Self::Error> {
+        let duration_module = duration_module(py)?;
+        let kwargs = [("microseconds", self.microseconds)].into_py_dict(py)?;
+        let duration_instance = duration_module.call_method("Duration", (), Some(&kwargs))?;
+        Ok(duration_instance.into_bound())
+    }
+}

rust/src/lib.rs

@@ -5,6 +5,7 @@ use pyo3::prelude::*;
 use pyo3_log::ResetHandle;
 
 pub mod acl;
+pub mod duration;
 pub mod errors;
 pub mod events;
 pub mod http;

rust/src/rendezvous/mod.rs

@@ -35,6 +35,7 @@ use ulid::Ulid;
 
 use self::session::Session;
 use crate::{
+    duration::SynapseDuration,
     errors::{NotFoundError, SynapseError},
     http::{http_request_from_twisted, http_response_to_twisted, HeaderMapPyExt},
     UnwrapInfallible,
@@ -132,6 +133,8 @@ impl RendezvousHandler {
             .unwrap_infallible()
             .unbind();
 
+        let eviction_duration = SynapseDuration::from_milliseconds(eviction_interval);
+
         // Construct a Python object so that we can get a reference to the
         // evict method and schedule it to run.
         let self_ = Py::new(
@@ -149,7 +152,7 @@ impl RendezvousHandler {
         let evict = self_.getattr(py, "_evict")?;
         homeserver.call_method0("get_clock")?.call_method(
             "looping_call",
-            (evict, eviction_interval),
+            (evict, &eviction_duration),
             None,
         )?;