From 38af63d11e810ad574367a110d4b374d88a67f06 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E3=81=AA=E3=81=A4=E3=81=8D?= <i@ntk.me>
Date: Thu, 11 Jul 2024 11:43:49 -0700
Subject: [PATCH 1/2] Add force option to mailbox.put

---
 CHANGELOG.md           |  4 ++++
 lib/mailbox.dart       |  7 ++++---
 pubspec.yaml           |  2 +-
 test/mailbox_test.dart | 10 ++++++++++
 4 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9acca14..81b3933 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.3.0
+
+- Add `force` option to `Mailbox`'s `put` method.
+
 ## 0.2.0
 
 - Lower SDK lower bound to 3.0.0.
diff --git a/lib/mailbox.dart b/lib/mailbox.dart
index 0871a7c..e8096f0 100644
--- a/lib/mailbox.dart
+++ b/lib/mailbox.dart
@@ -67,11 +67,12 @@ class Mailbox {
 
   /// Place a message into the mailbox if has space for it.
   ///
-  /// If mailbox already contains a message then [put] will throw.
-  void put(Uint8List message) {
+  /// If mailbox already contains a message then [put] will throw, unless
+  /// [force] is set to `true`.
+  void put(Uint8List message, {bool force = false}) {
     final buffer = message.isEmpty ? nullptr : _toBuffer(message);
     _mutex.runLocked(() {
-      if (_mailbox.ref.state != _stateEmpty) {
+      if (!force && _mailbox.ref.state != _stateEmpty) {
         throw StateError('Mailbox is full');
       }
 
diff --git a/pubspec.yaml b/pubspec.yaml
index e16317f..bf93c3f 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: native_synchronization
 description: Low level synchronization primitives built on dart:ffi.
-version: 0.2.0
+version: 0.3.0
 repository: https://github.com/dart-lang/native_synchronization
 
 environment:
diff --git a/test/mailbox_test.dart b/test/mailbox_test.dart
index 2400d56..ad1526e 100644
--- a/test/mailbox_test.dart
+++ b/test/mailbox_test.dart
@@ -29,4 +29,14 @@ void main() {
     expect(value[41], equals(42));
     expect(await helperResult, equals('success'));
   });
+
+  test('mailbox throws', () {
+    final mailbox = Mailbox();
+    mailbox.put(Uint8List(42)..[41] = 42);
+    expect(() => mailbox.put(Uint8List(0)), throwsA(TypeMatcher<StateError>()));
+    mailbox.put(Uint8List(0), force: true);
+    final value = mailbox.take();
+    expect(value, isA<Uint8List>());
+    expect(value.length, equals(0));
+  });
 }

From 861cf748bf3168346d32d77eef2c1b956ca32dc2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E3=81=AA=E3=81=A4=E3=81=8D?= <i@ntk.me>
Date: Thu, 11 Jul 2024 16:28:22 -0700
Subject: [PATCH 2/2] Free buffer for dropped message

---
 lib/mailbox.dart | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/mailbox.dart b/lib/mailbox.dart
index e8096f0..05ce900 100644
--- a/lib/mailbox.dart
+++ b/lib/mailbox.dart
@@ -72,8 +72,14 @@ class Mailbox {
   void put(Uint8List message, {bool force = false}) {
     final buffer = message.isEmpty ? nullptr : _toBuffer(message);
     _mutex.runLocked(() {
-      if (!force && _mailbox.ref.state != _stateEmpty) {
-        throw StateError('Mailbox is full');
+      if (_mailbox.ref.state != _stateEmpty) {
+        if (!force) {
+          throw StateError('Mailbox is full');
+        }
+
+        if (_mailbox.ref.bufferLength > 0) {
+          malloc.free(_mailbox.ref.buffer);
+        }
       }
 
       _mailbox.ref.state = _stateFull;