From d44fdc92ca95ecf15ce2d3f6c235e4218ce36e77 Mon Sep 17 00:00:00 2001
From: Jordan Rose <jrose@signal.org>
Date: Fri, 9 Aug 2024 16:37:08 -0700
Subject: [PATCH] backup: Canonicalize Timestamps and Durations as milliseconds

This is closer to the raw value used for most protobuf fields, and
avoids printing as an object containing secs+nsecs.
---
 rust/message-backup/src/backup/time.rs        | 31 +++++++++++++++++--
 .../tests/res/canonical-backup.expected.json  |  5 +--
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/rust/message-backup/src/backup/time.rs b/rust/message-backup/src/backup/time.rs
index 9482ec77..c16f6f5f 100644
--- a/rust/message-backup/src/backup/time.rs
+++ b/rust/message-backup/src/backup/time.rs
@@ -6,10 +6,10 @@
 use std::ops::Add;
 use std::time::{SystemTime, UNIX_EPOCH};
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, serde::Serialize)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Timestamp(SystemTime);
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, serde::Serialize)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Duration(std::time::Duration);
 
 impl Timestamp {
@@ -34,6 +34,19 @@ impl Timestamp {
     }
 }
 
+impl serde::Serialize for Timestamp {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        let offset = self
+            .0
+            .duration_since(UNIX_EPOCH)
+            .expect("should not be possible to construct a Timestamp older than UNIX_EPOCH");
+        serde::Serialize::serialize(&Duration(offset), serializer)
+    }
+}
+
 impl Duration {
     pub(super) const ZERO: Self = Self(std::time::Duration::ZERO);
     pub(super) const TWELVE_HOURS: Self = Self(std::time::Duration::from_secs(60 * 60 * 12));
@@ -43,6 +56,20 @@ impl Duration {
     }
 }
 
+impl serde::Serialize for Duration {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        assert!(
+            self.0.as_millis() * 1_000_000 == self.0.as_nanos(),
+            "should not be possible to construct a Duration with sub-millisecond precision ({:?})",
+            self.0
+        );
+        self.0.as_millis().serialize(serializer)
+    }
+}
+
 impl Add<Duration> for Timestamp {
     type Output = Timestamp;
 
diff --git a/rust/message-backup/tests/res/canonical-backup.expected.json b/rust/message-backup/tests/res/canonical-backup.expected.json
index a40ddddb..8988decf 100644
--- a/rust/message-backup/tests/res/canonical-backup.expected.json
+++ b/rust/message-backup/tests/res/canonical-backup.expected.json
@@ -31,10 +31,7 @@
       "story_view_receipts_enabled": true,
       "has_seen_group_story_education_sheet": true,
       "has_completed_username_onboarding": true,
-      "universal_expire_timer": {
-        "secs": 3600,
-        "nanos": 0
-      },
+      "universal_expire_timer": 3600000,
       "preferred_reaction_emoji": [
         "🏎️"
       ],