WindowServer+LibGUI: Allow arbitrary number of rects in messages.

To get truly atomic updates, add a mechanism for passing arbitrary amounts
of extra data along with WindowServer messages. This allows us to pass all
the rects in a single message.

Servers/WindowServer/WSAPITypes.h

@@ -109,12 +109,14 @@ struct WSAPI_ServerMessage {
     };
     Type type { Invalid };
     int window_id { -1 };
+    unsigned extra_size { 0 };
 
     union {
         int text_length { 0 };
         int rect_count;
     };
 
+    static const int max_inline_rect_count = 1;
     union {
         char text[512];
         WSAPI_Rect rects[32];
@@ -214,13 +216,16 @@ struct WSAPI_ClientMessage {
     };
     Type type { Invalid };
     int window_id { -1 };
+    unsigned extra_size { 0 };
     union {
         int text_length { 0 };
         int rect_count;
     };
+
+    static const int max_inline_rect_count = 1;
     union {
         char text[512];
-        WSAPI_Rect rects[32];
+        WSAPI_Rect rects[max_inline_rect_count];
     };
     int value { 0 };
 

Servers/WindowServer/WSClientConnection.cpp

@@ -70,8 +70,11 @@ void WSClientConnection::post_error(const String& error_message)
     post_message(message);
 }
 
-void WSClientConnection::post_message(const WSAPI_ServerMessage& message)
+void WSClientConnection::post_message(const WSAPI_ServerMessage& message, const ByteBuffer& extra_data)
 {
+    if (!extra_data.is_empty())
+        const_cast<WSAPI_ServerMessage&>(message).extra_size = extra_data.size();
+
     int nwritten = write(m_fd, &message, sizeof(message));
     if (nwritten < 0) {
         if (errno == EPIPE) {
@@ -83,6 +86,20 @@ void WSClientConnection::post_message(const WSAPI_ServerMessage& message)
     }
 
     ASSERT(nwritten == sizeof(message));
+
+    if (!extra_data.is_empty()) {
+        nwritten = write(m_fd, extra_data.data(), extra_data.size());
+        if (nwritten < 0) {
+            if (errno == EPIPE) {
+                dbgprintf("WSClientConnection::post_message: Disconnected from peer during extra_data write.\n");
+                return;
+            }
+            perror("WSClientConnection::post_message write (extra_data)");
+            ASSERT_NOT_REACHED();
+        }
+
+        ASSERT(nwritten == extra_data.size());
+    }
 }
 
 void WSClientConnection::notify_about_new_screen_rect(const Rect& rect)
@@ -93,19 +110,28 @@ void WSClientConnection::notify_about_new_screen_rect(const Rect& rect)
     post_message(message);
 }
 
-void WSClientConnection::event(CEvent& message)
+void WSClientConnection::event(CEvent& event)
 {
-    if (static_cast<WSEvent&>(message).is_client_request()) {
-        on_request(static_cast<const WSAPIClientRequest&>(message));
+    if (static_cast<WSEvent&>(event).is_client_request()) {
+        on_request(static_cast<const WSAPIClientRequest&>(event));
         return;
     }
 
-    if (message.type() == WSEvent::WM_ClientDisconnected) {
-        int client_id = static_cast<const WSClientDisconnectedNotification&>(message).client_id();
+    if (event.type() == WSEvent::WM_ClientDisconnected) {
+        int client_id = static_cast<const WSClientDisconnectedNotification&>(event).client_id();
         dbgprintf("WSClientConnection: Client disconnected: %d\n", client_id);
         delete this;
         return;
     }
+
+    CObject::event(event);
+}
+
+void WSClientConnection::did_misbehave()
+{
+    dbgprintf("WSClientConnection{%p} (id=%d, pid=%d) misbehaved, disconnecting.\n", this, m_client_id, m_pid);
+    // FIXME: We should make sure we avoid processing any further messages from this client.
+    delete_later();
 }
 
 void WSClientConnection::handle_request(const WSAPICreateMenubarRequest&)
@@ -484,13 +510,14 @@ void WSClientConnection::post_paint_message(WSWindow& window)
     message.window_id = window.window_id();
     auto rect_set = window.take_pending_paint_rects();
     auto& rects = rect_set.rects();
-    // FIXME: Break it into multiple batches if needed.
-    ASSERT(rects.size() <= 32);
     message.rect_count = rects.size();
-    for (int i = 0; i < rects.size(); ++i)
+    for (int i = 0; i < min(WSAPI_ServerMessage::max_inline_rect_count, rects.size()); ++i)
         message.rects[i] = rects[i];
     message.paint.window_size = window.size();
-    post_message(message);
+    ByteBuffer extra_data;
+    if (rects.size() > WSAPI_ServerMessage::max_inline_rect_count)
+        extra_data = ByteBuffer::wrap((void*)&rects[WSAPI_ServerMessage::max_inline_rect_count], (rects.size() - WSAPI_ServerMessage::max_inline_rect_count) * sizeof(WSAPI_Rect));
+    post_message(message, extra_data);
 }
 
 void WSClientConnection::handle_request(const WSAPIInvalidateRectRequest& request)

Servers/WindowServer/WSClientConnection.h

@@ -21,7 +21,7 @@ public:
     static WSClientConnection* from_client_id(int client_id);
     static void for_each_client(Function<void(WSClientConnection&)>);
 
-    void post_message(const WSAPI_ServerMessage&);
+    void post_message(const WSAPI_ServerMessage&, const ByteBuffer& = { });
 
     int client_id() const { return m_client_id; }
     WSMenuBar* app_menubar() { return m_app_menubar.ptr(); }
@@ -39,6 +39,8 @@ public:
     void notify_about_new_screen_rect(const Rect&);
     void post_paint_message(WSWindow&);
 
+    void did_misbehave();
+
 private:
     virtual void event(CEvent&) override;
 

Servers/WindowServer/WSEventLoop.cpp

@@ -115,7 +115,23 @@ static WSWindowType from_api(WSAPI_WindowType api_type)
     }
 }
 
-void WSEventLoop::on_receive_from_client(int client_id, const WSAPI_ClientMessage& message)
+static Vector<Rect, 32> get_rects(const WSAPI_ClientMessage& message, const ByteBuffer& extra_data)
+{
+    Vector<Rect, 32> rects;
+    if (message.rect_count > (WSAPI_ClientMessage::max_inline_rect_count + extra_data.size() / sizeof(WSAPI_Rect))) {
+        return { };
+    }
+    for (int i = 0; i < min(WSAPI_ClientMessage::max_inline_rect_count, message.rect_count); ++i)
+        rects.append(message.rects[i]);
+    if (!extra_data.is_empty()) {
+        auto* extra_rects = reinterpret_cast<const WSAPI_Rect*>(extra_data.data());
+        for (int i = 0; i < (extra_data.size() / sizeof(WSAPI_Rect)); ++i)
+            rects.append(extra_rects[i]);
+    }
+    return rects;
+}
+
+bool WSEventLoop::on_receive_from_client(int client_id, const WSAPI_ClientMessage& message, ByteBuffer&& extra_data)
 {
     WSClientConnection& client = *WSClientConnection::from_client_id(client_id);
     switch (message.type) {
@@ -192,18 +208,20 @@ void WSEventLoop::on_receive_from_client(int client_id, const WSAPI_ClientMessag
         post_event(client, make<WSAPIGetClipboardContentsRequest>(client_id));
         break;
     case WSAPI_ClientMessage::Type::InvalidateRect: {
-        Vector<Rect, 32> rects;
-        ASSERT(message.rect_count <= 32);
-        for (int i = 0; i < message.rect_count; ++i)
-            rects.append(message.rects[i]);
+        auto rects = get_rects(message, extra_data);
+        if (rects.is_empty()) {
+            client.did_misbehave();
+            return false;
+        }
         post_event(client, make<WSAPIInvalidateRectRequest>(client_id, message.window_id, rects));
         break;
     }
     case WSAPI_ClientMessage::Type::DidFinishPainting: {
-        Vector<Rect, 32> rects;
-        ASSERT(message.rect_count <= 32);
-        for (int i = 0; i < message.rect_count; ++i)
-            rects.append(message.rects[i]);
+        auto rects = get_rects(message, extra_data);
+        if (rects.is_empty()) {
+            client.did_misbehave();
+            return false;
+        }
         post_event(client, make<WSAPIDidFinishPaintingNotification>(client_id, message.window_id, rects));
         break;
     }
@@ -232,6 +250,7 @@ void WSEventLoop::on_receive_from_client(int client_id, const WSAPI_ClientMessag
     default:
         break;
     }
+    return true;
 }
 
 void WSEventLoop::add_file_descriptors_for_select(fd_set& fds, int& max_fd_added)
@@ -279,7 +298,22 @@ void WSEventLoop::drain_client(WSClientConnection& client)
             perror("read");
             ASSERT_NOT_REACHED();
         }
-        on_receive_from_client(client.client_id(), message);
+        ByteBuffer extra_data;
+        if (message.extra_size) {
+            if (message.extra_size >= 32768) {
+                dbgprintf("message.extra_size is way too large\n");
+                return client.did_misbehave();
+            }
+
+            extra_data = ByteBuffer::create_uninitialized(message.extra_size);
+            int extra_nread = read(client.fd(), extra_data.data(), extra_data.size());
+            if (extra_nread != message.extra_size) {
+                dbgprintf("extra_nread(%d) != extra_size(%d)\n", extra_nread, extra_data.size());
+                return client.did_misbehave();
+            }
+        }
+        if (!on_receive_from_client(client.client_id(), message, move(extra_data)))
+            return;
         ++messages_received;
     }
 }

Servers/WindowServer/WSEventLoop.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <LibCore/CEventLoop.h>
+#include <AK/ByteBuffer.h>
 
 class WSClientConnection;
 struct WSAPI_ClientMessage;
@@ -20,7 +21,7 @@ private:
     void drain_mouse();
     void drain_keyboard();
     void drain_client(WSClientConnection&);
-    void on_receive_from_client(int client_id, const WSAPI_ClientMessage&);
+    bool on_receive_from_client(int client_id, const WSAPI_ClientMessage&, ByteBuffer&& extra_data);
 
     int m_keyboard_fd { -1 };
     int m_mouse_fd { -1 };

Servers/WindowServer/WSMenu.cpp

@@ -134,6 +134,8 @@ void WSMenu::event(CEvent& event)
         clear_hovered_item();
         return;
     }
+
+    CObject::event(event);
 }
 
 void WSMenu::clear_hovered_item()

Servers/WindowServer/WSWindowFrame.cpp

@@ -239,7 +239,7 @@ void WSWindowFrame::on_mouse_event(const WSMouseEvent& event)
         return;
     }
 
-    if (event.type() == WSEvent::MouseMove && event.buttons() == 0) {
+    if (m_window.is_resizable() && event.type() == WSEvent::MouseMove && event.buttons() == 0) {
         constexpr ResizeDirection direction_for_hot_area[3][3] = {
             { ResizeDirection::UpLeft, ResizeDirection::Up, ResizeDirection::UpRight },
             { ResizeDirection::Left, ResizeDirection::None, ResizeDirection::Right },
@@ -256,6 +256,6 @@ void WSWindowFrame::on_mouse_event(const WSMouseEvent& event)
         return;
     }
 
-    if (event.button() == MouseButton::Left)
+    if (m_window.is_resizable() && event.button() == MouseButton::Left)
         wm.start_window_resize(m_window, event.translated(rect().location()));
 }

Servers/WindowServer/WSWindowManager.cpp

@@ -681,7 +681,7 @@ void WSWindowManager::process_mouse_event(const WSMouseEvent& event, WSWindow*&
                 start_window_drag(window, event);
                 return IterationDecision::Abort;
             }
-            if (m_keyboard_modifiers == Mod_Logo && event.type() == WSEvent::MouseDown && event.button() == MouseButton::Right && !window.is_blocked_by_modal_window()) {
+            if (window.is_resizable() && m_keyboard_modifiers == Mod_Logo && event.type() == WSEvent::MouseDown && event.button() == MouseButton::Right && !window.is_blocked_by_modal_window()) {
                 start_window_resize(window, event);
                 return IterationDecision::Abort;
             }
@@ -983,6 +983,8 @@ void WSWindowManager::event(CEvent& event)
         compose();
         return;
     }
+
+    CObject::event(event);
 }
 
 void WSWindowManager::set_highlight_window(WSWindow* window)