Refactor StdoutEventHandler buffering logic and null handling

Author: rishika0212

packages/devtools_app/lib/src/screens/logging/logging_controller.dart

@@ -1,3 +1,5 @@
+
+
 // Copyright 2019 The Flutter Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file or at https://developers.google.com/open-source/licenses/bsd.
@@ -849,55 +851,13 @@ class StdoutEventHandler {
   final String name;
   final bool isError;
 
-  LogData? buffer;
-  Timer? timer;
+  LogData? _buffer;
+  Timer? _timer;
 
   void handle(Event e) {
     final message = decodeBase64(e.bytes!);
 
-    if (buffer != null) {
-      timer?.cancel();
-
-      if (message == '\n') {
-        loggingController.log(
-          LogData(
-            buffer!.kind,
-            buffer!.details! + message,
-            buffer!.timestamp,
-            summary: buffer!.summary! + message,
-            isError: buffer!.isError,
-            isolateRef: e.isolateRef,
-          ),
-        );
-        buffer = null;
-        return;
-      }
-
-      // If the buffered message ends with a newline, the next message is a
-      // continuation of the same print statement (e.g. debugPrint('line1\nline2')
-      // is sent by the VM as two events: 'line1\n' and 'line2'). Combine them
-      // into a single log entry.
-      // See: https://github.com/flutter/devtools/issues/9557
-      if (buffer!.details!.endsWith('\n')) {
-        final combined = LogData(
-          buffer!.kind,
-          buffer!.details! + message,
-          buffer!.timestamp,
-          summary: buffer!.summary,
-          isError: buffer!.isError,
-          isolateRef: e.isolateRef,
-        );
-        buffer = combined;
-        timer = Timer(const Duration(milliseconds: 1), () {
-          loggingController.log(buffer!);
-          buffer = null;
-        });
-        return;
-      }
-
-      loggingController.log(buffer!);
-      buffer = null;
-    }
+    if (_handleBufferedMessage(message, e)) return;
 
     const maxLength = 200;
 
@@ -918,13 +878,70 @@ class StdoutEventHandler {
     if (message == '\n') {
       loggingController.log(data);
     } else {
-      buffer = data;
-      timer = Timer(const Duration(milliseconds: 1), () {
-        loggingController.log(buffer!);
-        buffer = null;
-      });
+      _setBuffer(data);
     }
   }
+
+  bool _handleBufferedMessage(String message, Event e) {
+    if (_buffer case final currentBuffer?) {
+      _timer?.cancel();
+
+      if (message == '\n') {
+        loggingController.log(
+          LogData(
+            currentBuffer.kind,
+            currentBuffer.details! + message,
+            currentBuffer.timestamp,
+            summary: currentBuffer.summary! + message,
+            isError: currentBuffer.isError,
+            isolateRef: e.isolateRef,
+          ),
+        );
+        _buffer = null;
+        return true;
+      }
+
+      // If the buffered message ends with a newline, the next message is a
+      // continuation of the same print statement (e.g. debugPrint('line1\nline2')
+      // is sent by the VM as two events: 'line1\n' and 'line2'). Combine them
+      // into a single log entry.
+      // See: https://github.com/flutter/devtools/issues/9557
+      if (currentBuffer.details!.endsWith('\n')) {
+        _setBuffer(
+          LogData(
+            currentBuffer.kind,
+            currentBuffer.details! + message,
+            currentBuffer.timestamp,
+            summary: currentBuffer.summary,
+            isError: currentBuffer.isError,
+            isolateRef: e.isolateRef,
+          ),
+        );
+        return true;
+      }
+
+      loggingController.log(currentBuffer);
+      _buffer = null;
+    }
+    return false;
+  }
+
+  void _setBuffer(LogData data) {
+    _buffer = data;
+    _timer?.cancel();
+    _timer = Timer(const Duration(milliseconds: 1), () {
+      if (_buffer case final currentBuffer?) {
+        loggingController.log(currentBuffer);
+        _buffer = null;
+      }
+    });
+  }
+
+  @visibleForTesting
+  LogData? get buffer => _buffer;
+
+  @visibleForTesting
+  Timer? get timer => _timer;
 }
 
 bool _isNotNull(InstanceRef? serviceRef) {