Add mir server side decoration strategy

src/core/symbols.map

@@ -1,5 +1,5 @@
 MIR_CORE_2.9 {
- global:
+global:
   extern "C++" {
     mir::AnonymousShmFile::?AnonymousShmFile*;
     mir::AnonymousShmFile::AnonymousShmFile*;
@@ -29,3 +29,4 @@ MIR_CORE_2.9 {
   };
 local: *;
 };
+

src/include/server/mir/decoration_strategy.h

@@ -0,0 +1,33 @@
+/*
+ * Copyright © Canonical Ltd.
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or 3 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <cstdint>
+namespace mir
+{
+class DecorationStrategy
+{
+public:
+    enum class DecorationsType : uint32_t
+    {
+        csd,
+        ssd
+    };
+
+    virtual ~DecorationStrategy() = default;
+    virtual auto default_style() const -> DecorationsType = 0;
+    virtual auto request_style(DecorationsType type) const -> DecorationsType = 0;
+};
+}

src/include/server/mir/default_server_configuration.h

@@ -36,6 +36,7 @@ template<class Observer>
 class ObserverMultiplexer;
 
 class ConsoleServices;
+class DecorationStrategy;
 
 namespace dispatch
 {
@@ -334,6 +335,9 @@ class DefaultServerConfiguration : public virtual ServerConfiguration
 
     auto default_reports() -> std::shared_ptr<void>;
 
+    auto the_decoration_strategy() -> std::shared_ptr<DecorationStrategy> override;
+    void set_the_decoration_strategy(std::shared_ptr<DecorationStrategy> strategy) override;
+
 protected:
     std::shared_ptr<options::Option> the_options() const;
     std::shared_ptr<input::DefaultInputDeviceHub>  the_default_input_device_hub();
@@ -420,6 +424,7 @@ class DefaultServerConfiguration : public virtual ServerConfiguration
     CachedPtr<cookie::Authority> cookie_authority;
     CachedPtr<input::KeyMapper> key_mapper;
     std::shared_ptr<ConsoleServices> console_services;
+    std::shared_ptr<DecorationStrategy> decoration_strategy;
 
 private:
     std::shared_ptr<options::Configuration> const configuration_options;

src/include/server/mir/server.h

@@ -74,6 +74,7 @@ class RendererFactory;
 class Fd;
 class MainLoop;
 class ServerStatusListener;
+class DecorationStrategy;
 
 enum class OptionType
 {
@@ -469,6 +470,8 @@ class Server
     void set_enabled_wayland_extensions(std::vector<std::string> const& extensions);
 /** @} */
 
+    auto the_decoration_strategy() const -> std::shared_ptr<DecorationStrategy>;
+    void set_the_decoration_strategy(std::shared_ptr<DecorationStrategy> strategy);
 private:
     struct ServerConfiguration;
     struct Self;

src/include/server/mir/server_configuration.h

@@ -72,6 +72,7 @@ class ServerStatusListener;
 class DisplayChanger;
 class EmergencyCleanup;
 class ConsoleServices;
+class DecorationStrategy;
 
 class ServerConfiguration
 {
@@ -111,6 +112,8 @@ class ServerConfiguration
     virtual void set_wayland_extension_filter(WaylandProtocolExtensionFilter const& extension_filter) = 0;
     virtual void set_enabled_wayland_extensions(std::vector<std::string> const& extensions) = 0;
 
+    virtual auto the_decoration_strategy() -> std::shared_ptr<DecorationStrategy> = 0;
+    virtual void set_the_decoration_strategy(std::shared_ptr<DecorationStrategy> strategy) = 0;
 protected:
     ServerConfiguration() = default;
     virtual ~ServerConfiguration() = default;

src/server/default_server_configuration.cpp

@@ -38,6 +38,7 @@
 #include "default_emergency_cleanup.h"
 #include "mir/graphics/platform.h"
 #include "mir/console_services.h"
+#include "mir/decoration_strategy.h"
 
 namespace mc = mir::compositor;
 namespace geom = mir::geometry;
@@ -198,3 +199,23 @@ auto mir::DefaultServerConfiguration::the_logger()
             return std::make_shared<ml::DumbConsoleLogger>();
         });
 }
+
+auto mir::DefaultServerConfiguration::the_decoration_strategy() -> std::shared_ptr<mir::DecorationStrategy>
+{
+    if(!decoration_strategy) {
+        class DefaultDecorationStrategy: public mir::DecorationStrategy
+        {
+            DecorationsType default_style() const override { return DecorationsType::csd; }
+            DecorationsType request_style(DecorationsType type) const override { return type; }
+        };
+
+        decoration_strategy = std::make_shared<DefaultDecorationStrategy>();
+    }
+
+    return decoration_strategy;
+}
+
+void mir::DefaultServerConfiguration::set_the_decoration_strategy(std::shared_ptr<mir::DecorationStrategy> strategy)
+{
+    decoration_strategy = strategy;
+}

src/server/frontend_wayland/wayland_connector.cpp

@@ -239,7 +239,8 @@ mf::WaylandConnector::WaylandConnector(
     std::unique_ptr<WaylandExtensions> extensions_,
     WaylandProtocolExtensionFilter const& extension_filter,
     bool enable_key_repeat,
-    std::shared_ptr<scene::SessionLock> const& session_lock)
+    std::shared_ptr<scene::SessionLock> const& session_lock,
+    std::shared_ptr<mir::DecorationStrategy> const& decoration_strategy)
     : extension_filter{extension_filter},
       display{wl_display_create(), &cleanup_display},
       pause_signal{eventfd(0, EFD_CLOEXEC | EFD_SEMAPHORE)},
@@ -325,7 +326,8 @@ mf::WaylandConnector::WaylandConnector(
         screen_shooter,
         main_loop,
         desktop_file_manager,
-        session_lock_});
+        session_lock_,
+        decoration_strategy});
 
     shm_global = std::make_unique<WlShm>(display.get(), executor);
 

src/server/frontend_wayland/wayland_connector.h

@@ -36,6 +36,7 @@ class Executor;
 class MainLoop;
 template<typename>
 class ObserverRegistrar;
+class DecorationStrategy;
 
 namespace compositor
 {
@@ -110,6 +111,7 @@ class WaylandExtensions
         std::shared_ptr<MainLoop> main_loop;
         std::shared_ptr<DesktopFileManager> desktop_file_manager;
         std::shared_ptr<scene::SessionLock> session_lock;
+        std::shared_ptr<mir::DecorationStrategy> decoration_strategy;
     };
 
     WaylandExtensions() = default;
@@ -161,7 +163,8 @@ class WaylandConnector : public Connector
         std::unique_ptr<WaylandExtensions> extensions,
         WaylandProtocolExtensionFilter const& extension_filter,
         bool enable_key_repeat,
-        std::shared_ptr<scene::SessionLock> const& session_lock);
+        std::shared_ptr<scene::SessionLock> const& session_lock,
+        std::shared_ptr<DecorationStrategy> const& decoration_strategy);
 
     ~WaylandConnector() override;
 

src/server/frontend_wayland/wayland_default_configuration.cpp

@@ -218,7 +218,7 @@ std::vector<ExtensionBuilder> const internal_extension_builders = {
         }),
     make_extension_builder<mw::XdgDecorationManagerV1>([](auto const& ctx)
 	{
-	    return mf::create_xdg_decoration_unstable_v1(ctx.display);
+	    return mf::create_xdg_decoration_unstable_v1(ctx.display, ctx.decoration_strategy);
 	})
 };
 
@@ -375,7 +375,8 @@ std::shared_ptr<mf::Connector>
                     wayland_extension_hooks),
                 wayland_extension_filter,
                 enable_repeat,
-                the_session_lock());
+                the_session_lock(),
+                the_decoration_strategy());
         });
 }