Send update dispatcher though FFI

include/AModule.hpp

@@ -17,6 +17,7 @@ class AModule : public IModule {
   operator Gtk::Widget &() override;
   auto doAction(const std::string &name) -> void override;
 
+  /// Emitting on this dispatcher triggers a update() call
   Glib::Dispatcher dp;
 
  protected:

include/modules/cffi.hpp

@@ -22,21 +22,21 @@ class CFFI : public AModule {
   CFFI(const std::string&, const std::string&, const Json::Value&);
   virtual ~CFFI();
 
-  // virtual auto update() -> void override;
-  // virtual operator Gtk::Widget&() override;
-
   virtual auto refresh(int signal) -> void override;
   virtual auto doAction(const std::string& name) -> void override;
+  virtual auto update() -> void override;
 
  private:
   ///
   void* cffi_instance_ = nullptr;
 
-  typedef void*(InitFn)(GtkContainer*, const struct wbcffi_config_entry* config_entries,
+  typedef void*(InitFn)(GtkContainer* root_widget, const void (*trigger_update)(void*),
+                        void* trigger_update_arg, const struct wbcffi_config_entry* config_entries,
                         size_t config_entries_len);
   typedef void(DenitFn)(void* instance);
   typedef void(RefreshFn)(void* instance, int signal);
   typedef void(DoActionFn)(void* instance, const char* name);
+  typedef void(UpdateFn)(void* instance);
 
   // FFI hooks
   struct {
@@ -44,6 +44,7 @@ class CFFI : public AModule {
     std::function<DenitFn> deinit = nullptr;
     std::function<RefreshFn> refresh = [](void*, int) {};
     std::function<DoActionFn> doAction = [](void*, const char*) {};
+    std::function<UpdateFn> update = [](void*) {};
   } hooks_;
 };
 

resources/custom_modules/cffi_example/README.md

@@ -7,6 +7,9 @@ Most language can implement the required functions and constants (C, C++, Rust,
 Go, Python, ...), meaning you can develop custom modules using your language of
 choice, as long as there's GTK bindings.
 
+Symbols to implement are documented in the
+[waybar_cffi_module.h](waybar_cffi_module.h) file.
+
 # Usage
 
 ## Building this module

resources/custom_modules/cffi_example/main.c

@@ -19,7 +19,8 @@ void onclicked(GtkButton* button) {
 // You must
 const size_t wbcffi_version = 1;
 
-void* wbcffi_init(GtkContainer* root, const struct wbcffi_config_entry* config_entries,
+void* wbcffi_init(GtkContainer* root_widget, void (*trigger_update)(void*),
+                  void* trigger_update_arg, const struct wbcffi_config_entry* config_entries,
                   size_t config_entries_len) {
   printf("cffi_example: init config:\n");
   for (size_t i = 0; i < config_entries_len; i++) {
@@ -28,7 +29,7 @@ void* wbcffi_init(GtkContainer* root, const struct wbcffi_config_entry* config_e
 
   // Allocate the instance object
   Instance* inst = malloc(sizeof(Instance));
-  inst->root = root;
+  inst->root = root_widget;
 
   // Add a container for displaying the next widgets
   inst->container = GTK_BOX(gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 5));
@@ -51,13 +52,18 @@ void* wbcffi_init(GtkContainer* root, const struct wbcffi_config_entry* config_e
   printf("cffi_example inst=%p: init success ! (%d total instances)\n", inst, ++instance_count);
   return inst;
 }
+
 void wbcffi_deinit(void* instance) {
   printf("cffi_example inst=%p: free memory\n", instance);
   free(instance);
 }
+
+void wbcffi_update(void* instance) { printf("cffi_example inst=%p: Update request\n", instance); }
+
 void wbcffi_refresh(void* instance, int signal) {
   printf("cffi_example inst=%p: Received refresh signal %d\n", instance, signal);
 }
+
 void wbcffi_doaction(void* instance, const char* name) {
   printf("cffi_example inst=%p: doAction(%s)\n", instance, name);
 }

resources/custom_modules/cffi_example/waybar_cffi_module.h

@@ -23,12 +23,16 @@ struct wbcffi_config_entry {
 /// MANDATORY CFFI function
 ///
 /// @param root_widget        Root GTK widget instantiated by Waybar
+/// @param trigger_update     Call this function with trigger_update_arg as argument to trigger
+///                           wbcffi_update() on the next GTK main event loop iteration
+/// @param trigger_update_arg Argument for trigger_update call
 /// @param config_entries     Flat representation of the module JSON config. The data only available
 ///                           during wbcffi_init call.
 /// @param config_entries_len Number of entries in `config_entries`
 ///
 /// @return A untyped pointer to module data, NULL if the module failed to load.
-void* wbcffi_init(GtkContainer* root_widget, const struct wbcffi_config_entry* config_entries,
+void* wbcffi_init(GtkContainer* root_widget, const void (*trigger_update)(void*),
+                  void* trigger_update_arg, const struct wbcffi_config_entry* config_entries,
                   size_t config_entries_len);
 
 /// Module deinit/delete function, called when Waybar is closed or when the module is removed
@@ -38,8 +42,15 @@ void* wbcffi_init(GtkContainer* root_widget, const struct wbcffi_config_entry* c
 /// @param instance Module instance data (as returned by `wbcffi_init`)
 void wbcffi_deinit(void* instance);
 
-/// When Waybar receives a POSIX signal, it forwards the signal to each module, calling this
+/// Called from the GTK main event loop, to update the UI
-/// function
+///
+/// Optional CFFI function
+///
+/// @param instance Module instance data (as returned by `wbcffi_init`)
+/// @param action_name Action name
+void wbcffi_update(void* instance);
+
+/// Called when Waybar receives a POSIX signal and forwards it to each module
 ///
 /// Optional CFFI function
 ///
@@ -47,12 +58,14 @@ void wbcffi_deinit(void* instance);
 /// @param signal Signal ID
 void wbcffi_refresh(void* instance, int signal);
 
+/// Called on module action (see
+/// https://github.com/Alexays/Waybar/wiki/Configuration#module-actions-config)
 ///
 /// Optional CFFI function
 ///
 /// @param instance Module instance data (as returned by `wbcffi_init`)
-/// @param name Action name
+/// @param action_name Action name
-void wbcffi_doaction(void* instance, const char* name);
+void wbcffi_doaction(void* instance, const char* action_name);
 
 #ifdef __cplusplus
 }

src/modules/cffi.cpp

@@ -39,6 +39,9 @@ CFFI::CFFI(const std::string& name, const std::string& id, const Json::Value& co
       throw std::runtime_error{std::string{"Missing wbcffi_deinit function: "} + dlerror()};
     }
     // Optional functions
+    if (auto fn = reinterpret_cast<UpdateFn*>(dlsym(handle, "wbcffi_update"))) {
+      hooks_.update = fn;
+    }
     if (auto fn = reinterpret_cast<RefreshFn*>(dlsym(handle, "wbcffi_refresh"))) {
       hooks_.refresh = fn;
     }
@@ -70,8 +73,10 @@ CFFI::CFFI(const std::string& name, const std::string& id, const Json::Value& co
   }
 
   // Call init
-  cffi_instance_ = hooks_.init(dynamic_cast<Gtk::Container*>(&event_box_)->gobj(),
+  cffi_instance_ = hooks_.init(
-                               config_entries.data(), config_entries.size());
+      dynamic_cast<Gtk::Container*>(&event_box_)->gobj(),
+      [](void* dp) { ((Glib::Dispatcher*)dp)->emit(); }, &dp, config_entries.data(),
+      config_entries.size());
 
   // Handle init failures
   if (cffi_instance_ == nullptr) {
@@ -85,6 +90,14 @@ CFFI::~CFFI() {
   }
 }
 
+auto CFFI::update() -> void {
+  assert(cffi_instance_ != nullptr);
+  hooks_.update(cffi_instance_);
+
+  // Execute the on-update command set in config
+  AModule::update();
+}
+
 auto CFFI::refresh(int signal) -> void {
   assert(cffi_instance_ != nullptr);
   hooks_.refresh(cffi_instance_, signal);
@@ -93,15 +106,7 @@ auto CFFI::refresh(int signal) -> void {
 auto CFFI::doAction(const std::string& name) -> void {
   assert(cffi_instance_ != nullptr);
   if (!name.empty()) {
-    // TODO: Make a decision
-    // Calling AModule::doAction and hooks_.doAction will execute the action twice if it is
-    // configured in AModule::eventActionMap_ and implemented in the CFFI module.
-    //
-    // Should we block AModule::doAction() if the action is implemented in hooks_.doAction() ?
-    // (doAction could return true if the action has been processed)
-    //
     hooks_.doAction(cffi_instance_, name.c_str());
-    AModule::doAction(name);
   }
 }