LibGUI: Fix compiler warnings.

LibGUI/GEventLoop.cpp

@@ -367,7 +367,11 @@ bool GEventLoop::drain_messages_from_server()
         if (message.extra_size) {
             extra_data = ByteBuffer::create_uninitialized(message.extra_size);
             int extra_nread = read(s_windowserver_fd, extra_data.data(), extra_data.size());
-            ASSERT(extra_nread == message.extra_size);
+            if (extra_nread < 0) {
+                perror("read");
+                ASSERT_NOT_REACHED();
+            }
+            ASSERT((size_t)extra_nread == message.extra_size);
         }
         m_unprocessed_bundles.append({ move(message), move(extra_data) });
     }
@@ -380,17 +384,21 @@ bool GEventLoop::post_message_to_server(const WSAPI_ClientMessage& message, cons
 
     struct iovec iov[2];
     int iov_count = 1;
-    iov[0].iov_base = (void*)&message;
+    iov[0].iov_base = const_cast<WSAPI_ClientMessage*>(&message);
     iov[0].iov_len = sizeof(message);
 
     if (!extra_data.is_empty()) {
-        iov[1].iov_base = (void*)extra_data.data();
+        iov[1].iov_base = const_cast<byte*>(extra_data.data());
         iov[1].iov_len = extra_data.size();
         ++iov_count;
     }
 
     int nwritten = writev(s_windowserver_fd, iov, iov_count);
-    ASSERT(nwritten == sizeof(message) + extra_data.size());
+    if (nwritten < 0) {
+        perror("writev");
+        ASSERT_NOT_REACHED();
+    }
+    ASSERT((size_t)nwritten == sizeof(message) + extra_data.size());
 
     return true;
 }

LibGUI/GFileSystemModel.cpp

@@ -23,10 +23,10 @@ struct GFileSystemModel::Node {
     GModelIndex index(const GFileSystemModel& model) const
     {
         if (!parent)
-            return model.create_index(0, 0, (void*)this);
+            return model.create_index(0, 0, const_cast<Node*>(this));
         for (int row = 0; row < parent->children.size(); ++row) {
             if (parent->children[row] == this)
-                return model.create_index(row, 0, (void*)this);
+                return model.create_index(row, 0, const_cast<Node*>(this));
         }
         ASSERT_NOT_REACHED();
     }

LibGUI/GWindow.cpp

@@ -626,7 +626,7 @@ void GWindow::set_icon_path(const StringView& path)
     WSAPI_ClientMessage message;
     message.type = WSAPI_ClientMessage::Type::SetWindowIcon;
     message.window_id = m_window_id;
-    ASSERT(path.length() < sizeof(message.text));
+    ASSERT(path.length() < (int)sizeof(message.text));
     strcpy(message.text, path.characters());
     message.text_length = path.length();
     GEventLoop::post_message_to_server(message);

LibGUI/GWindow.h

@@ -170,6 +170,6 @@ private:
     bool m_show_titlebar { true };
     bool m_keybind_mode { false };
     String m_entered_keybind;
-    size_t m_max_keybind_length { 0 };
+    int m_max_keybind_length { 0 };
     HashMap<String, WeakPtr<GWidget>> m_keyboard_activation_targets;
 };

SharedGraphics/Font.cpp

@@ -107,7 +107,7 @@ RefPtr<Font> Font::load_from_memory(const byte* data)
 
     size_t bytes_per_glyph = sizeof(unsigned) * header.glyph_height;
 
-    auto* rows = (unsigned*)(data + sizeof(FontFileHeader));
+    auto* rows = const_cast<unsigned*>((const unsigned*)(data + sizeof(FontFileHeader)));
     byte* widths = nullptr;
     if (header.is_variable_width)
         widths = (byte*)(rows) + 256 * bytes_per_glyph;

SharedGraphics/PNGLoader.cpp

@@ -27,7 +27,7 @@ static_assert(sizeof(PNG_IHDR) == 13);
 
 struct Scanline {
     byte filter { 0 };
-    ByteBuffer data;
+    ByteBuffer data { };
 };
 
 struct PNGLoadingContext {
@@ -61,9 +61,9 @@ public:
     template<typename T>
     bool read(T& value)
     {
-        if (m_size_remaining < sizeof(T))
+        if (m_size_remaining < (int)sizeof(T))
             return false;
-        value = *((NetworkOrdered<T>*)m_data_ptr);
+        value = *((const NetworkOrdered<T>*)m_data_ptr);
         m_data_ptr += sizeof(T);
         m_size_remaining -= sizeof(T);
         return true;
@@ -383,7 +383,7 @@ static RefPtr<GraphicsBitmap> load_png_impl(const byte* data, int data_size)
 
 static bool process_IHDR(const ByteBuffer& data, PNGLoadingContext& context)
 {
-    if (data.size() < sizeof(PNG_IHDR))
+    if (data.size() < (int)sizeof(PNG_IHDR))
         return false;
     auto& ihdr = *(const PNG_IHDR*)data.pointer();
     context.width = ihdr.width;