+// _ ___ _
+// ___| | __ _ ___ ___ |_ _|_ __ ___ _ __ | |
+// / __| |/ _` / __/ __| | || '_ ` _ \| '_ \| |
+// | (__| | (_| \__ \__ \ | || | | | | | |_) | |
+// \___|_|\__,_|___/___/ |___|_| |_| |_| .__/|_|
+// |_|
+class AFBClient::Impl {
+ friend class AFBClient;
+
+ // This is the AFBClient interface impl
+ int init(int port, char const *token);
+ int dispatch();
+
+ // WM API
+ int requestSurface(const char *label);
+ int activateSurface(const char *label);
+ int deactivateSurface(const char *label);
+ int endDraw(const char *label);
+
+ void set_event_handler(enum EventType et, handler_fun func);
+
+ Impl();
+ ~Impl();
+
+ struct afb_wsj1 *wsj1;
+ struct sd_event *loop;
+
+ std::set<std::string> labels;
+ std::map<EventType, handler_fun> handlers;
+
+public:
+ void event(char const *et, char const *label);
+};
+
+namespace {
+
+constexpr const int token_maxlen = 20;
+constexpr const char *const wmAPI = "winman";
+
+#ifdef NDEBUG
+#define TRACE()
+#define TRACEN(N)
+#else
+#define CONCAT_(X, Y) X##Y
+#define CONCAT(X, Y) CONCAT_(X, Y)
+
+#define TRACE() \
+ ScopeTrace __attribute__((unused)) CONCAT(trace_scope_, __LINE__)(__func__)
+#define TRACEN(N) \
+ ScopeTrace __attribute__((unused)) CONCAT(named_trace_scope_, __LINE__)(#N)
+
+struct ScopeTrace {
+ thread_local static int indent;
+ char const *f{};
+ explicit ScopeTrace(char const *func) : f(func) {
+ fprintf(stderr, "%*s%s -->\n", 2 * indent++, "", this->f);
+ }
+ ~ScopeTrace() { fprintf(stderr, "%*s%s <--\n", 2 * --indent, "", this->f); }
+};
+thread_local int ScopeTrace::indent = 0;
+#endif
+
+/* called when wsj1 receives a method invocation */
+void onCall(void *closure, const char *api, const char *verb,
+ struct afb_wsj1_msg *msg) {
+ TRACE();
+ UNUSED(closure);
+ UNUSED(verb);
+ UNUSED(api);
+ UNUSED(msg);
+}
+
+/* called when wsj1 receives an event */
+void onEvent(void *closure, const char *event, afb_wsj1_msg *msg) {
+ TRACE();
+ reinterpret_cast<AFBClient::Impl *>(closure)->event(
+ event, json_object_get_string(
+ json_object_object_get(afb_wsj1_msg_object_j(msg), "data")));
+}
+
+/* called when wsj1 hangsup */
+void onHangup(void *closure, afb_wsj1 *wsj1) {
+ TRACE();
+ UNUSED(closure);
+ UNUSED(wsj1);
+ fputs("Hangup, the WindowManager vanished\n", stderr);
+ exit(1);
+}
+
+constexpr struct afb_wsj1_itf itf = {
+ onHangup, onCall, onEvent,
+};
+
+// XXX: I am not sure this is the right thing to do though...
+std::recursive_mutex dispatch_mutex;
+
+void dispatch_internal(struct sd_event *loop) {
+ std::lock_guard<std::recursive_mutex> guard(dispatch_mutex);
+ TRACE();
+ sd_event_run(loop, -1);
+}
+
+/// object will be json_object_put
+int api_call(struct sd_event *loop, struct afb_wsj1 *wsj1, const char *verb,
+ json_object *object,
+ const std::function<void(bool, json_object *)> &onReply) {
+ TRACE();
+
+ // We need to wrap the actual onReply call once in order to
+ // *look* like a normal functions pointer (std::functions<>
+ // with captures cannot convert to function pointers).
+ // Alternatively we could setup a local struct and use it as
+ // closure, but I think it is cleaner this way.
+ int call_rc = 0;
+ std::atomic<bool> returned{};
+ returned.store(false, std::memory_order_relaxed);
+ std::function<void(bool, json_object *)> wrappedOnReply =
+ [&returned, &call_rc, &onReply](bool ok, json_object *j) {
+ TRACEN(wrappedOnReply);
+ call_rc = ok ? 0 : -EINVAL;
+ // We know it failed, but there may be an explanation in the
+ // json object.
+ {
+ TRACEN(onReply);
+ onReply(ok, j);
+ }
+ returned.store(true, std::memory_order_release);
+ };
+
+ // make the actual call, use wrappedOnReply as closure
+ int rc = afb_wsj1_call_j(
+ wsj1, wmAPI, verb, object,
+ [](void *closure, afb_wsj1_msg *msg) {
+ TRACEN(callClosure);
+ auto *onReply =
+ reinterpret_cast<std::function<void(bool, json_object *)> *>(
+ closure);
+ (*onReply)(!(afb_wsj1_msg_is_reply_ok(msg) == 0),
+ afb_wsj1_msg_object_j(msg));
+ },
+ &wrappedOnReply);
+
+ if (rc < 0) {
+ fprintf(
+ stderr, "calling %s/%s(%s) failed: %m\n", wmAPI, verb,
+ json_object_to_json_string_ext(object, JSON_C_TO_STRING_PRETTY));
+ // Call the reply handler regardless with a NULL json_object*
+ onReply(false, nullptr);
+ } else {
+ // We need to dispatch until "returned" got set, this is necessary
+ // if events get triggered by the call (and would be dispatched before
+ // the actual call-reply).
+ while (!returned.load(std::memory_order_consume)) {
+ std::lock_guard<std::recursive_mutex> guard(dispatch_mutex);
+ if (!returned.load(std::memory_order_consume)) {
+ dispatch_internal(loop);
+ }
+ }
+
+ // return the actual API call result
+ rc = call_rc;
+ }