macOS: Fix Command-A in password fields

Install a macOS-specific secure text field hotkey handler so Command-A selects the full contents of password controls when Cocoa does not route the shortcut through wxWidgets accelerators. Keep the existing wxWidgets accelerator handler for Command-V and Command-A, and recognize the standard paste/select-all IDs when they do reach the C++ event path.

Add Objective-C++ compilation support for the macOS helper and include it in the GUI target only on macOS.

Fixes https://github.com/veracrypt/VeraCrypt/issues/1567

src/Main/MacOSXSecureTextFieldHotkeys.mm

@@ -0,0 +1,114 @@
+/*
+ Copyright (c) 2013-2025 AM Crypto. All rights reserved.
+
+ Governed by the Apache License 2.0 the full text of which is
+ contained in the file License.txt included in VeraCrypt binary and source
+ code distribution packages.
+*/
+
+#include "System.h"
+#include "MacOSXSecureTextFieldHotkeys.h"
+
+#ifdef TC_MACOSX
+#import <Cocoa/Cocoa.h>
+
+#ifndef __has_feature
+#define __has_feature(x) 0
+#endif
+
+#if defined(MAC_OS_X_VERSION_10_12) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_12
+#define VC_NSEVENT_MASK_KEY_DOWN NSEventMaskKeyDown
+#define VC_NSEVENT_MODIFIER_FLAG_COMMAND NSEventModifierFlagCommand
+#define VC_NSEVENT_MODIFIER_FLAG_CONTROL NSEventModifierFlagControl
+#define VC_NSEVENT_MODIFIER_FLAG_OPTION NSEventModifierFlagOption
+#define VC_NSEVENT_MODIFIER_FLAG_SHIFT NSEventModifierFlagShift
+#define VC_NSEVENT_TYPE_KEY_DOWN NSEventTypeKeyDown
+#else
+#define VC_NSEVENT_MASK_KEY_DOWN NSKeyDownMask
+#define VC_NSEVENT_MODIFIER_FLAG_COMMAND NSCommandKeyMask
+#define VC_NSEVENT_MODIFIER_FLAG_CONTROL NSControlKeyMask
+#define VC_NSEVENT_MODIFIER_FLAG_OPTION NSAlternateKeyMask
+#define VC_NSEVENT_MODIFIER_FLAG_SHIFT NSShiftKeyMask
+#define VC_NSEVENT_TYPE_KEY_DOWN NSKeyDown
+#endif
+
+namespace
+{
+	id SecureTextFieldHotkeyMonitor = nil;
+
+	bool IsCommandA (NSEvent *event)
+	{
+		if ([event type] != VC_NSEVENT_TYPE_KEY_DOWN)
+			return false;
+
+		const NSEventModifierFlags shortcutModifiers =
+			VC_NSEVENT_MODIFIER_FLAG_COMMAND | VC_NSEVENT_MODIFIER_FLAG_CONTROL | VC_NSEVENT_MODIFIER_FLAG_OPTION | VC_NSEVENT_MODIFIER_FLAG_SHIFT;
+
+		if (([event modifierFlags] & shortcutModifiers) != VC_NSEVENT_MODIFIER_FLAG_COMMAND)
+			return false;
+
+		NSString *characters = [event charactersIgnoringModifiers];
+		if ([characters length] != 1)
+			return false;
+
+		unichar character = [characters characterAtIndex:0];
+		return character == 'a' || character == 'A';
+	}
+
+	wxTextCtrl *GetFocusedSecureTextCtrl ()
+	{
+		wxWindow *focusedCtrl = wxWindow::FindFocus();
+		if (!focusedCtrl
+			|| !focusedCtrl->IsKindOf (wxCLASSINFO (wxTextCtrl))
+			|| !(focusedCtrl->GetWindowStyle() & wxTE_PASSWORD))
+		{
+			return nullptr;
+		}
+
+		return static_cast <wxTextCtrl *> (focusedCtrl);
+	}
+
+	NSEvent *HandleSecureTextFieldHotkey (NSEvent *event)
+	{
+		if (!IsCommandA (event))
+			return event;
+
+		wxTextCtrl *secureTextCtrl = GetFocusedSecureTextCtrl();
+		if (!secureTextCtrl)
+			return event;
+
+		secureTextCtrl->SelectAll();
+		return nil;
+	}
+}
+
+namespace VeraCrypt
+{
+	void InstallMacOSXSecureTextFieldHotkeys ()
+	{
+		if (SecureTextFieldHotkeyMonitor)
+			return;
+
+		SecureTextFieldHotkeyMonitor = [NSEvent addLocalMonitorForEventsMatchingMask:VC_NSEVENT_MASK_KEY_DOWN handler:^NSEvent *(NSEvent *event) {
+			return HandleSecureTextFieldHotkey (event);
+		}];
+#if !__has_feature(objc_arc)
+		[SecureTextFieldHotkeyMonitor retain];
+#endif
+	}
+
+	void UninstallMacOSXSecureTextFieldHotkeys ()
+	{
+		if (!SecureTextFieldHotkeyMonitor)
+			return;
+
+		id monitor = SecureTextFieldHotkeyMonitor;
+		SecureTextFieldHotkeyMonitor = nil;
+
+		[NSEvent removeMonitor:monitor];
+#if !__has_feature(objc_arc)
+		[monitor release];
+#endif
+	}
+}
+#endif