From 0d602e73988f63eb39e3699ba9d11adca3fcfa6b Mon Sep 17 00:00:00 2001
From: Sven Gehring <cbrxde@gmail.com>
Date: Fri, 1 Mar 2024 13:31:41 +0100
Subject: [PATCH] feat: add support for frameTimeout option

This adds a frameTimeout option that can be passed a Duration.
The option is expected to be used with streams where isLive=true,
so that there is a timeout between receiving frames.
If no new frame is received for the given timeout duration,
the stream is automatically reloaded.
---
 README.md          |  1 +
 lib/src/mjpeg.dart | 43 +++++++++++++++++++++++++++++++++++++++----
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index d8fe6d4..9734024 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,7 @@ Parameter | Description
 --- | ---
 `isLive` | Whether or not the stream should be loaded continuously
 `timeout` | HTTP Timeout when fetching the MJPEG stream
+`frameTimeout` | If no frame is received for this duration, the stream will be reloaded. This should only be used together with `isLive` as there's no point in waiting for new frames in a stream that's not live.
 `width` | Force width
 `height` | Force height
 `error` | Error builder used when an error occurred
diff --git a/lib/src/mjpeg.dart b/lib/src/mjpeg.dart
index a0c6c22..594ace4 100644
--- a/lib/src/mjpeg.dart
+++ b/lib/src/mjpeg.dart
@@ -43,6 +43,7 @@ class Mjpeg extends HookWidget {
   final double? height;
   final bool isLive;
   final Duration timeout;
+  final Duration? frameTimeout;
   final WidgetBuilder? loading;
   final Client? httpClient;
   final Widget Function(BuildContext contet, dynamic error, dynamic stack)?
@@ -55,6 +56,7 @@ class Mjpeg extends HookWidget {
     this.isLive = false,
     this.width,
     this.timeout = const Duration(seconds: 5),
+    this.frameTimeout,
     this.height,
     this.fit,
     required this.stream,
@@ -78,6 +80,7 @@ class Mjpeg extends HookWidget {
               isLive && visible.visible,
               headers,
               timeout,
+              frameTimeout,
               httpClient ?? Client(),
               preprocessor ?? MjpegPreprocessor(),
               isMounted,
@@ -87,9 +90,10 @@ class Mjpeg extends HookWidget {
           isLive,
           visible.visible,
           timeout,
+          frameTimeout,
           httpClient,
           preprocessor,
-          isMounted
+          isMounted,
         ]);
     final key = useMemoized(() => UniqueKey(), [manager]);
 
@@ -153,26 +157,55 @@ class _StreamManager {
   final String stream;
   final bool isLive;
   final Duration _timeout;
+  final Duration? _frameTimeout;
   final Map<String, String> headers;
   final Client _httpClient;
   final MjpegPreprocessor _preprocessor;
   final bool Function() _mounted;
   // ignore: cancel_subscriptions
   StreamSubscription? _subscription;
+  Timer? _frameTimeoutTimer;
 
-  _StreamManager(this.stream, this.isLive, this.headers, this._timeout,
-      this._httpClient, this._preprocessor, this._mounted);
+  _StreamManager(
+    this.stream,
+    this.isLive,
+    this.headers,
+    this._timeout,
+    this._frameTimeout,
+    this._httpClient,
+    this._preprocessor,
+    this._mounted,
+  );
 
   Future<void> dispose() async {
     if (_subscription != null) {
       await _subscription!.cancel();
       _subscription = null;
     }
+    _frameTimeoutTimer?.cancel();
     _httpClient.close();
   }
 
+  void _resetFrameTimeoutTimer(
+    BuildContext context,
+    ValueNotifier<MemoryImage?> image,
+    ValueNotifier<List<dynamic>?> errorState,
+  ) {
+    if (_frameTimeout == null) return;
+
+    _frameTimeoutTimer?.cancel();
+    _frameTimeoutTimer = Timer(_frameTimeout!, () {
+      errorState.value = null;
+      updateStream(context, image, errorState);
+    });
+  }
+
   void _sendImage(BuildContext context, ValueNotifier<MemoryImage?> image,
-      ValueNotifier<dynamic> errorState, List<int> chunks) async {
+      ValueNotifier<List<dynamic>?> errorState, List<int> chunks) async {
+    // If frame timeout timer is active and we are expecting new frames,
+    // reset the timer on each frame received.
+    _resetFrameTimeoutTimer(context, image, errorState);
+
     // pass image through preprocessor sending to [Image] for rendering
     final List<int>? imageData = _preprocessor.process(chunks);
     if (imageData == null) return;
@@ -258,6 +291,8 @@ class _StreamManager {
           image.value = null;
         }
       }
+    } finally {
+      _resetFrameTimeoutTimer(context, image, errorState);
     }
   }
 }