LibGUI+WindowServer: Add app-global keyboard shortcuts.

This patch adds a GShortcut class. Each GAction can have a GShortcut which
will cause the event loop to listen for that key combination app-globally
and activate the event in case it's pressed.

The shortcut will also be displayed when the action is added to a menu.

Use this to hook up Alt+Up with the "open parent directory" action in the
FileManager app. :^)

WindowServer/WSAPITypes.h

@@ -166,6 +166,8 @@ struct WSAPI_ClientMessage {
             int menubar_id;
             int menu_id;
             unsigned identifier;
+            char shortcut_text[32];
+            int shortcut_text_length;
         } menu;
         struct {
             WSAPI_Rect rect;

WindowServer/WSClientConnection.cpp

@@ -210,14 +210,13 @@ void WSClientConnection::handle_request(WSAPIAddMenuItemRequest& request)
 {
     int menu_id = request.menu_id();
     unsigned identifier = request.identifier();
-    String text = request.text();
     auto it = m_menus.find(menu_id);
     if (it == m_menus.end()) {
         post_error("Bad menu ID");
         return;
     }
     auto& menu = *(*it).value;
-    menu.add_item(make<WSMenuItem>(identifier, move(text)));
+    menu.add_item(make<WSMenuItem>(identifier, request.text(), request.shortcut_text()));
     WSAPI_ServerMessage response;
     response.type = WSAPI_ServerMessage::Type::DidAddMenuItem;
     response.menu.menu_id = menu_id;

WindowServer/WSMenu.cpp

@@ -29,8 +29,13 @@ int WSMenu::width() const
 {
     int longest = 0;
     for (auto& item : m_items) {
-        if (item->type() == WSMenuItem::Text)
-            longest = max(longest, font().width(item->text()));
+        if (item->type() == WSMenuItem::Text) {
+            int item_width = font().width(item->text());
+            if (!item->shortcut_text().is_empty())
+                item_width += padding_between_text_and_shortcut() + font().width(item->shortcut_text());
+
+            longest = max(longest, item_width);
+        }
     }
 
     return max(longest, rect_in_menubar().width()) + horizontal_padding();
@@ -91,6 +96,9 @@ void WSMenu::draw()
                 text_color = Color::White;
             }
             painter.draw_text(item->rect().translated(left_padding(), 0), item->text(), TextAlignment::CenterLeft, text_color);
+            if (!item->shortcut_text().is_empty()) {
+                painter.draw_text(item->rect().translated(-right_padding(), 0), item->shortcut_text(), TextAlignment::CenterRight, text_color);
+            }
         } else if (item->type() == WSMenuItem::Separator) {
             Point p1(1, item->rect().center().y());
             Point p2(width() - 2, item->rect().center().y());

WindowServer/WSMenu.h

@@ -73,6 +73,7 @@ public:
     void close();
 
 private:
+    int padding_between_text_and_shortcut() const { return 50; }
     void did_activate(WSMenuItem&);
     WSClientConnection* m_client { nullptr };
     int m_menu_id { 0 };

WindowServer/WSMenuItem.cpp

@@ -1,9 +1,10 @@
 #include "WSMenuItem.h"
 
-WSMenuItem::WSMenuItem(unsigned identifier, const String& text)
+WSMenuItem::WSMenuItem(unsigned identifier, const String& text, const String& shortcut_text)
     : m_type(Text)
     , m_identifier(identifier)
     , m_text(text)
+    , m_shortcut_text(shortcut_text)
 {
 }
 

WindowServer/WSMenuItem.h

@@ -12,7 +12,7 @@ public:
         Separator,
     };
 
-    explicit WSMenuItem(unsigned identifier, const String& text);
+    explicit WSMenuItem(unsigned identifier, const String& text, const String& shortcut_text = { });
     explicit WSMenuItem(Type);
     ~WSMenuItem();
 
@@ -20,6 +20,7 @@ public:
     bool enabled() const { return m_enabled; }
 
     String text() const { return m_text; }
+    String shortcut_text() const { return m_shortcut_text; }
 
     void set_rect(const Rect& rect) { m_rect = rect; }
     Rect rect() const { return m_rect; }
@@ -31,6 +32,7 @@ private:
     bool m_enabled { true };
     unsigned m_identifier { 0 };
     String m_text;
+    String m_shortcut_text;
     Rect m_rect;
 };
 

WindowServer/WSMessage.h

@@ -189,22 +189,25 @@ private:
 
 class WSAPIAddMenuItemRequest : public WSAPIClientRequest {
 public:
-    WSAPIAddMenuItemRequest(int client_id, int menu_id, unsigned identifier, const String& text)
+    WSAPIAddMenuItemRequest(int client_id, int menu_id, unsigned identifier, const String& text, const String& shortcut_text)
         : WSAPIClientRequest(WSMessage::APIAddMenuItemRequest, client_id)
         , m_menu_id(menu_id)
         , m_identifier(identifier)
         , m_text(text)
+        , m_shortcut_text(shortcut_text)
     {
     }
 
     int menu_id() const { return m_menu_id; }
     unsigned identifier() const { return m_identifier; }
     String text() const { return m_text; }
+    String shortcut_text() const { return m_shortcut_text; }
 
 private:
     int m_menu_id { 0 };
     unsigned m_identifier { 0 };
     String m_text;
+    String m_shortcut_text;
 };
 
 class WSAPIAddMenuSeparatorRequest : public WSAPIClientRequest {

WindowServer/WSMessageLoop.cpp

@@ -294,7 +294,8 @@ void WSMessageLoop::on_receive_from_client(int client_id, const WSAPI_ClientMess
         break;
     case WSAPI_ClientMessage::Type::AddMenuItem:
         ASSERT(message.text_length < (ssize_t)sizeof(message.text));
-        post_message(client, make<WSAPIAddMenuItemRequest>(client_id, message.menu.menu_id, message.menu.identifier, String(message.text, message.text_length)));
+        ASSERT(message.menu.shortcut_text_length < (ssize_t)sizeof(message.menu.shortcut_text));
+        post_message(client, make<WSAPIAddMenuItemRequest>(client_id, message.menu.menu_id, message.menu.identifier, String(message.text, message.text_length), String(message.menu.shortcut_text, message.menu.shortcut_text_length)));
         break;
     case WSAPI_ClientMessage::Type::CreateWindow:
         ASSERT(message.text_length < (ssize_t)sizeof(message.text));