Userland: Properly define IPC::encode and IPC::decode specializations

In order to avoid the base encode/decode methods from being used (and
failing a static assertion), we must be sure to declare/define the
custom type implementations as template specializations.

After this, LibIPC is no longer sensitive to include order.

Userland/Libraries/LibCore/AnonymousBuffer.h

@@ -74,7 +74,10 @@ private:
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Core::AnonymousBuffer const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Core::AnonymousBuffer&);
 
 }

Userland/Libraries/LibCore/DateTime.h

@@ -54,7 +54,10 @@ private:
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Core::DateTime const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Core::DateTime&);
 
 }

Userland/Libraries/LibCore/Proxy.h

@@ -52,6 +52,11 @@ struct ProxyData {
 }
 
 namespace IPC {
+
+template<>
 bool encode(Encoder&, Core::ProxyData const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Core::ProxyData&);
+
 }

Userland/Libraries/LibDNS/Answer.cpp

@@ -100,12 +100,14 @@ ErrorOr<void> AK::Formatter<DNS::RecordClass>::format(AK::FormatBuilder& builder
 
 namespace IPC {
 
+template<>
 bool encode(Encoder& encoder, DNS::Answer const& answer)
 {
     encoder << answer.name().as_string() << (u16)answer.type() << (u16)answer.class_code() << answer.ttl() << answer.record_data() << answer.mdns_cache_flush();
     return true;
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, DNS::Answer& answer)
 {
     String name;

Userland/Libraries/LibDNS/Answer.h

@@ -94,7 +94,10 @@ struct AK::Formatter<DNS::RecordClass> : StandardFormatter {
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, DNS::Answer const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, DNS::Answer&);
 
 }

Userland/Libraries/LibGfx/Color.cpp

@@ -366,12 +366,14 @@ Vector<Color> Color::tints(u32 steps, float max) const
 
 }
 
+template<>
 bool IPC::encode(Encoder& encoder, Color const& color)
 {
     encoder << color.value();
     return true;
 }
 
+template<>
 ErrorOr<void> IPC::decode(Decoder& decoder, Color& color)
 {
     u32 rgba;

Userland/Libraries/LibGfx/Color.h

@@ -568,7 +568,10 @@ struct Formatter<Gfx::Color> : public Formatter<StringView> {
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Gfx::Color const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Gfx::Color&);
 
 }

Userland/Libraries/LibGfx/Point.cpp

@@ -51,12 +51,14 @@ String FloatPoint::to_string() const
 
 namespace IPC {
 
+template<>
 bool encode(Encoder& encoder, Gfx::IntPoint const& point)
 {
     encoder << point.x() << point.y();
     return true;
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, Gfx::IntPoint& point)
 {
     int x = 0;

Userland/Libraries/LibGfx/Point.h

@@ -290,7 +290,10 @@ struct Formatter<Gfx::Point<T>> : Formatter<FormatString> {
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Gfx::IntPoint const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Gfx::IntPoint&);
 
 }

Userland/Libraries/LibGfx/Rect.cpp

@@ -30,12 +30,14 @@ String FloatRect::to_string() const
 
 namespace IPC {
 
+template<>
 bool encode(Encoder& encoder, Gfx::IntRect const& rect)
 {
     encoder << rect.location() << rect.size();
     return true;
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, Gfx::IntRect& rect)
 {
     Gfx::IntPoint point;

Userland/Libraries/LibGfx/Rect.h

@@ -1031,7 +1031,10 @@ struct Formatter<Gfx::Rect<T>> : Formatter<FormatString> {
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Gfx::IntRect const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Gfx::IntRect&);
 
 }

Userland/Libraries/LibGfx/ShareableBitmap.cpp

@@ -22,6 +22,7 @@ ShareableBitmap::ShareableBitmap(NonnullRefPtr<Bitmap> bitmap, Tag)
 
 namespace IPC {
 
+template<>
 bool encode(Encoder& encoder, Gfx::ShareableBitmap const& shareable_bitmap)
 {
     encoder << shareable_bitmap.is_valid();
@@ -39,6 +40,7 @@ bool encode(Encoder& encoder, Gfx::ShareableBitmap const& shareable_bitmap)
     return true;
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, Gfx::ShareableBitmap& shareable_bitmap)
 {
     bool valid = false;

Userland/Libraries/LibGfx/ShareableBitmap.h

@@ -34,7 +34,10 @@ private:
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Gfx::ShareableBitmap const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Gfx::ShareableBitmap&);
 
 }

Userland/Libraries/LibGfx/Size.cpp

@@ -27,12 +27,14 @@ String FloatSize::to_string() const
 
 namespace IPC {
 
+template<>
 bool encode(Encoder& encoder, Gfx::IntSize const& size)
 {
     encoder << size.width() << size.height();
     return true;
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, Gfx::IntSize& size)
 {
     int width = 0;

Userland/Libraries/LibGfx/Size.h

@@ -188,7 +188,10 @@ struct Formatter<Gfx::Size<T>> : Formatter<FormatString> {
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Gfx::IntSize const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Gfx::IntSize&);
 
 }

Userland/Libraries/LibIPC/Decoder.cpp

@@ -170,6 +170,7 @@ ErrorOr<void> Decoder::decode([[maybe_unused]] File& file)
     return {};
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, Core::AnonymousBuffer& buffer)
 {
     bool valid;
@@ -187,6 +188,7 @@ ErrorOr<void> decode(Decoder& decoder, Core::AnonymousBuffer& buffer)
     return {};
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, Core::DateTime& datetime)
 {
     i64 timestamp;
@@ -195,6 +197,7 @@ ErrorOr<void> decode(Decoder& decoder, Core::DateTime& datetime)
     return {};
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, Core::ProxyData& data)
 {
     UnderlyingType<decltype(data.type)> type;

Userland/Libraries/LibIPC/Encoder.cpp

@@ -196,6 +196,7 @@ Encoder& Encoder::operator<<(File const& file)
     return *this;
 }
 
+template<>
 bool encode(Encoder& encoder, Core::AnonymousBuffer const& buffer)
 {
     encoder << buffer.is_valid();
@@ -206,12 +207,14 @@ bool encode(Encoder& encoder, Core::AnonymousBuffer const& buffer)
     return true;
 }
 
+template<>
 bool encode(Encoder& encoder, Core::DateTime const& datetime)
 {
     encoder << static_cast<i64>(datetime.timestamp());
     return true;
 }
 
+template<>
 bool encode(Encoder& encoder, Core::ProxyData const& proxy)
 {
     encoder << to_underlying(proxy.type);

Userland/Libraries/LibWeb/Cookie/Cookie.cpp

@@ -38,6 +38,7 @@ SameSite same_site_from_string(StringView same_site_mode)
 
 }
 
+template<>
 bool IPC::encode(Encoder& encoder, Web::Cookie::Cookie const& cookie)
 {
     encoder << cookie.name;
@@ -56,6 +57,7 @@ bool IPC::encode(Encoder& encoder, Web::Cookie::Cookie const& cookie)
     return true;
 }
 
+template<>
 ErrorOr<void> IPC::decode(Decoder& decoder, Web::Cookie::Cookie& cookie)
 {
     TRY(decoder.decode(cookie.name));

Userland/Libraries/LibWeb/Cookie/Cookie.h

@@ -46,7 +46,10 @@ SameSite same_site_from_string(StringView same_site_mode);
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Web::Cookie::Cookie const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Web::Cookie::Cookie&);
 
 }

Userland/Libraries/LibWeb/Cookie/ParsedCookie.cpp

@@ -347,6 +347,7 @@ Optional<Core::DateTime> parse_date_time(StringView date_string)
 
 }
 
+template<>
 bool IPC::encode(Encoder& encoder, Web::Cookie::ParsedCookie const& cookie)
 {
     encoder << cookie.name;
@@ -362,6 +363,7 @@ bool IPC::encode(Encoder& encoder, Web::Cookie::ParsedCookie const& cookie)
     return true;
 }
 
+template<>
 ErrorOr<void> IPC::decode(Decoder& decoder, Web::Cookie::ParsedCookie& cookie)
 {
     TRY(decoder.decode(cookie.name));

Userland/Libraries/LibWeb/Cookie/ParsedCookie.h

@@ -32,7 +32,10 @@ Optional<ParsedCookie> parse_cookie(String const& cookie_string);
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Web::Cookie::ParsedCookie const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Web::Cookie::ParsedCookie&);
 
 }

Userland/Libraries/LibWeb/WebDriver/Response.cpp

@@ -27,6 +27,7 @@ Response::Response(Error&& error)
 
 }
 
+template<>
 bool IPC::encode(Encoder& encoder, Web::WebDriver::Response const& response)
 {
     response.visit(
@@ -46,6 +47,7 @@ bool IPC::encode(Encoder& encoder, Web::WebDriver::Response const& response)
     return true;
 }
 
+template<>
 ErrorOr<void> IPC::decode(Decoder& decoder, Web::WebDriver::Response& response)
 {
     ResponseType type {};

Userland/Libraries/LibWeb/WebDriver/Response.h

@@ -46,7 +46,10 @@ private:
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, Web::WebDriver::Response const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, Web::WebDriver::Response&);
 
 }

Userland/Services/WindowServer/ScreenLayout.h

@@ -73,9 +73,16 @@ public:
 
 namespace IPC {
 
+template<>
 bool encode(Encoder&, WindowServer::ScreenLayout::Screen const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, WindowServer::ScreenLayout::Screen&);
+
+template<>
 bool encode(Encoder&, WindowServer::ScreenLayout const&);
+
+template<>
 ErrorOr<void> decode(Decoder&, WindowServer::ScreenLayout&);
 
 }

Userland/Services/WindowServer/ScreenLayout.ipp

@@ -394,12 +394,14 @@ bool ScreenLayout::try_auto_add_display_connector(String const& device_path)
 
 namespace IPC {
 
-bool encode(Encoder& encoder, const WindowServer::ScreenLayout::Screen& screen)
+template<>
+bool encode(Encoder& encoder, WindowServer::ScreenLayout::Screen const& screen)
 {
     encoder << screen.mode << screen.device << screen.location << screen.resolution << screen.scale_factor;
     return true;
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, WindowServer::ScreenLayout::Screen& screen)
 {
     WindowServer::ScreenLayout::Screen::Mode mode;
@@ -416,12 +418,14 @@ ErrorOr<void> decode(Decoder& decoder, WindowServer::ScreenLayout::Screen& scree
     return {};
 }
 
-bool encode(Encoder& encoder, const WindowServer::ScreenLayout& screen_layout)
+template<>
+bool encode(Encoder& encoder, WindowServer::ScreenLayout const& screen_layout)
 {
     encoder << screen_layout.screens << screen_layout.main_screen_index;
     return true;
 }
 
+template<>
 ErrorOr<void> decode(Decoder& decoder, WindowServer::ScreenLayout& screen_layout)
 {
     Vector<WindowServer::ScreenLayout::Screen> screens;