feat(terminal): add opt-in OSC 52 clipboard writes (#16072)

* feat(terminal): add opt-in OSC 52 clipboard writes

* Remove dup tr

Signed-off-by: fufesou <linlong1266@gmail.com>

---------

Signed-off-by: fufesou <linlong1266@gmail.com>

flutter/lib/models/terminal_mouse_handler_input.dart

@@ -0,0 +1,162 @@
+part of 'terminal_mouse_handler.dart';
+
+/// xterm 4.0.0 encodes wheel buttons as 68..71; the extra bit reads as a Shift
+/// modifier, so strict full-screen apps ignore the report and never scroll.
+/// Upstream fix: TerminalStudio/xterm.dart#238.
+class WheelButtonFixMouseHandler implements TerminalMouseHandler {
+  const WheelButtonFixMouseHandler({
+    this.positionProvider,
+    this.suppressLeftButton,
+  });
+
+  final CellOffset? Function()? positionProvider;
+  final bool Function(TerminalMouseButtonState)? suppressLeftButton;
+
+  @override
+  String? call(TerminalMouseEvent event) {
+    if (!event.button.isWheel) {
+      if (event.button == TerminalMouseButton.left &&
+          suppressLeftButton?.call(event.buttonState) == true) {
+        return null;
+      }
+      return defaultMouseHandler(event);
+    }
+    // Same gate as UpDownMouseHandler: only the scroll modes report a wheel,
+    // and a wheel release is never reported, so the report is always a press.
+    if (!event.state.mouseMode.reportScroll ||
+        event.buttonState == TerminalMouseButtonState.up) {
+      return null;
+    }
+    return _reportWheel(event);
+  }
+
+  String _reportWheel(TerminalMouseEvent event) {
+    // Wheel buttons 4..7 go on the wire as 64..67, but `id` is 64 + 4..7.
+    final button = event.button.id - 4;
+    final position = positionProvider?.call() ?? event.position;
+    return encodeTerminalMouseReport(
+      event.state.mouseReportMode,
+      button,
+      position,
+    );
+  }
+}
+
+extension _TerminalMouseInput on _TerminalMouseInteractionState {
+  CellOffset? _cellAtPointer() {
+    final terminalView = _terminalView;
+    final pointerPosition = _pointerPosition;
+    if (terminalView == null || pointerPosition == null) return null;
+    final renderTerminal = terminalView.renderTerminal;
+    return renderTerminal.getCellOffset(
+      renderTerminal.globalToLocal(pointerPosition),
+    );
+  }
+
+  void _updatePointerPosition(PointerEvent event) =>
+      _pointerPosition = event.position;
+
+  void _handlePointerDown(PointerDownEvent event) {
+    _updatePointerPosition(event);
+    _suppressXtermLeftButton = false;
+    if (_startPendingTouchMouseDrag(event)) return;
+    if (_mouseDrag.handleDown(event, widget.terminal, _terminalView)) {
+      _prepareTerminalClipboardWrite();
+      if (kIsWeb) _suppressXtermLeftButton = true;
+      _clearSelectionDrag();
+      return;
+    }
+    if (event.kind != PointerDeviceKind.mouse ||
+        (event.buttons & kPrimaryMouseButton) != kPrimaryMouseButton) {
+      return;
+    }
+    _clearSelectionDrag();
+    final terminalView = _terminalView;
+    if (terminalView == null) return;
+    final renderTerminal = terminalView.renderTerminal;
+    final localPosition = renderTerminal.globalToLocal(event.position);
+    final selectionBuffer = widget.terminal.buffer;
+    _selectionPointerId = event.pointer;
+    _selectionBase = selectionBuffer.createAnchorFromOffset(
+      renderTerminal.getCellOffset(localPosition),
+    );
+    _selectionBuffer = selectionBuffer;
+    _selectionPointer = localPosition;
+  }
+
+  bool _startPendingTouchMouseDrag(PointerDownEvent event) {
+    if (!widget.reportTouchInput ||
+        event.kind != PointerDeviceKind.touch ||
+        !_mouseDrag.handleDown(
+          event,
+          widget.terminal,
+          _terminalView,
+          reportTouchInput: true,
+          deferReport: true,
+        )) {
+      return false;
+    }
+    _pendingTouchMouseDown = event;
+    _pendingTouchMouseTimer = Timer(
+      kLongPressTimeout,
+      _activatePendingTouchMouseDrag,
+    );
+    return true;
+  }
+
+  bool _activatePendingTouchMouseDrag({
+    bool cancelOnFailure = true,
+  }) {
+    if (_takePendingTouchMouseDrag() == null) return false;
+    if (_mouseDrag.activateDeferredDown(widget.terminal)) {
+      _prepareTerminalClipboardWrite();
+      _clearSelectionDrag();
+      return true;
+    }
+    if (cancelOnFailure) _mouseDrag.cancel();
+    return false;
+  }
+
+  PointerDownEvent? _takePendingTouchMouseDrag({int? pointer}) {
+    final pending = _pendingTouchMouseDown;
+    if (pending == null || pointer != null && pointer != pending.pointer) {
+      return null;
+    }
+    _pendingTouchMouseTimer?.cancel();
+    _pendingTouchMouseTimer = null;
+    _pendingTouchMouseDown = null;
+    return pending;
+  }
+
+  void _cancelPendingTouchMouseDrag({
+    int? pointer,
+    bool deferCancel = false,
+  }) {
+    if (_takePendingTouchMouseDrag(pointer: pointer) == null) return;
+    if (deferCancel) {
+      scheduleMicrotask(_mouseDrag.cancel);
+    } else {
+      _mouseDrag.cancel();
+    }
+  }
+
+  bool _handlePendingTouchMove(PointerMoveEvent event) {
+    final pending = _pendingTouchMouseDown;
+    if (pending == null || pending.pointer != event.pointer) return false;
+    if ((event.position - pending.position).distance > kTouchSlop) {
+      _cancelPendingTouchMouseDrag(
+        pointer: event.pointer,
+        deferCancel: true,
+      );
+    }
+    return true;
+  }
+
+  bool _consumeXtermLeftButtonSuppression(TerminalMouseButtonState state) {
+    final suppress = _suppressXtermLeftButton;
+    if (state == TerminalMouseButtonState.up) {
+      _suppressXtermLeftButton = false;
+    }
+    return suppress;
+  }
+}