feat: introduce KotlinInstant type for Kotlin bindings

crypto-ffi/bindings/android/build.gradle.kts

@@ -20,6 +20,7 @@ dependencies {
     implementation(kotlin("stdlib-jdk7"))
     implementation("${libs.jna.get()}@aar")
     implementation(libs.coroutines.core)
+    implementation(libs.kotlinx.datetime)
     implementation("androidx.annotation:annotation:1.9.1")
 
     androidTestImplementation(kotlin("test"))

crypto-ffi/bindings/gradle/libs.versions.toml

@@ -1,6 +1,7 @@
 [versions]
 kotlin = "1.9.25"
 coroutines = "1.7.3"
+kotlinx-datetime = "0.6.1"
 jna = "5.17.0"
 assertj = "3.24.2"
 espresso = "3.6.1"
@@ -29,3 +30,4 @@ espresso = { module = "androidx.test.espresso:espresso-core", version.ref = "esp
 android-junit = { module = "androidx.test.ext:junit", version.ref = "android-junit" }
 android-tools = { module = "com.android.tools.build:gradle", version.ref = "android-tools" }
 kotlin-gradle = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin", version.ref = "kotlin-gradle" }
+kotlinx-datetime = { module = "org.jetbrains.kotlinx:kotlinx-datetime", version.ref = "kotlinx-datetime" }

crypto-ffi/bindings/jvm/build.gradle.kts

@@ -20,6 +20,7 @@ dependencies {
     implementation(kotlin("stdlib-jdk7"))
     implementation(libs.jna)
     implementation(libs.coroutines.core)
+    implementation(libs.kotlinx.datetime)
     testImplementation(kotlin("test"))
     testImplementation(libs.coroutines.test)
     testImplementation(libs.assertj.core)

crypto-ffi/src/identity/x509.rs

@@ -2,7 +2,7 @@
 use wasm_bindgen::prelude::*;
 
 #[cfg(not(target_family = "wasm"))]
-use std::time::{Duration, SystemTime};
+use crate::Timestamp;
 
 /// Represents the parts of [WireIdentity][crate::WireIdentity] that are specific to a X509 certificate (and not a Basic one).
 ///
@@ -39,7 +39,7 @@ pub struct X509Identity {
 
     /// X509 certificate not before
     #[cfg(not(target_family = "wasm"))]
-    pub not_before: SystemTime,
+    pub not_before: Timestamp,
 
     /// X509 certificate not after as Unix timestamp
     #[cfg(target_family = "wasm")]
@@ -48,7 +48,7 @@ pub struct X509Identity {
 
     /// X509 certificate not after
     #[cfg(not(target_family = "wasm"))]
-    pub not_after: SystemTime,
+    pub not_after: Timestamp,
 }
 
 impl From<core_crypto::prelude::X509Identity> for X509Identity {
@@ -60,10 +60,10 @@ impl From<core_crypto::prelude::X509Identity> for X509Identity {
         let not_after = i.not_after;
 
         #[cfg(not(target_family = "wasm"))]
-        let not_before = SystemTime::UNIX_EPOCH + Duration::from_secs(i.not_before);
+        let not_before = Timestamp::from_epoch_secs(i.not_before);
 
         #[cfg(not(target_family = "wasm"))]
-        let not_after = SystemTime::UNIX_EPOCH + Duration::from_secs(i.not_after);
+        let not_after = Timestamp::from_epoch_secs(i.not_after);
 
         Self {
             handle: i.handle,

crypto-ffi/src/lib.rs

@@ -26,6 +26,8 @@ mod error;
 mod identity;
 mod metadata;
 mod proteus;
+#[cfg(not(target_family = "wasm"))]
+mod timestamp;
 
 pub use bundles::{
     commit::CommitBundle, group_info::GroupInfoBundle, proteus_auto_prekey::ProteusAutoPrekeyBundle,
@@ -70,3 +72,5 @@ pub use identity::{
     x509::X509Identity,
 };
 pub use metadata::{BuildMetadata, build_metadata, version};
+#[cfg(not(target_family = "wasm"))]
+pub use timestamp::Timestamp;

crypto-ffi/src/timestamp.rs

@@ -0,0 +1,47 @@
+//! Custom timestamp type for UniFFI bindings.
+//!
+//! This wrapper allows custom type mapping per target language:
+//! - Kotlin: maps to `kotlinx.datetime.Instant`
+//! - Swift: maps to `Date`
+//! - WASM: not changed
+//!
+//! This unifies timestamp handling across JVM/Android and KMP bindings.
+//! This can be removed once we fully migrate to Kotlin Multiplatform and
+//! stop generating JVM/Android bindings.
+
+use std::time::{Duration, SystemTime};
+
+/// A wrapper around `SystemTime` for FFI bindings with custom type mapping per language.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Timestamp(pub SystemTime);
+
+impl Timestamp {
+    /// Creates a new `Timestamp` from a `SystemTime`.
+    pub fn new(time: SystemTime) -> Self {
+        Self(time)
+    }
+
+    /// Creates a new `Timestamp` from seconds since the Unix epoch.
+    pub fn from_epoch_secs(secs: u64) -> Self {
+        Self(SystemTime::UNIX_EPOCH + Duration::from_secs(secs))
+    }
+
+    /// Returns the inner `SystemTime`.
+    pub fn into_inner(self) -> SystemTime {
+        self.0
+    }
+}
+
+impl From<SystemTime> for Timestamp {
+    fn from(time: SystemTime) -> Self {
+        Self(time)
+    }
+}
+
+impl From<Timestamp> for SystemTime {
+    fn from(timestamp: Timestamp) -> Self {
+        timestamp.0
+    }
+}
+
+uniffi::custom_type!(Timestamp, SystemTime);

crypto-ffi/uniffi-android.toml

@@ -1,3 +1,13 @@
 [bindings.kotlin]
 android = true
 android_cleaner = true
+
+[bindings.kotlin.custom_types.KotlinInstant]
+imports = [
+  "kotlinx.datetime.Instant",
+  "kotlinx.datetime.toKotlinInstant",
+  "kotlinx.datetime.toJavaInstant",
+]
+type_name = "Instant"
+lift = "{}.toKotlinInstant()"
+lower = "{}.toJavaInstant()"

crypto-ffi/uniffi.toml

@@ -2,6 +2,16 @@
 package_name = "com.wire.crypto"
 cdylib_name = "core_crypto_ffi"
 
+[bindings.kotlin.custom_types.Timestamp]
+imports = [
+  "kotlinx.datetime.Instant",
+  "kotlinx.datetime.toKotlinInstant",
+  "kotlinx.datetime.toJavaInstant",
+]
+type_name = "Instant"
+lift = "{}.toKotlinInstant()"
+lower = "{}.toJavaInstant()"
+
 [bindings.swift]
 cdylib_name = "core_crypto_ffi"
 ffi_module_name = "LibCoreCrypto"