server: Asynchronous Accept events

This detaches accept from the task workflow.

include/iserver.hpp

@@ -19,12 +19,23 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #pragma once
 #include <memory>
 #include "error.hpp"
+#include "event.hpp"
 #include "isocket.hpp"
 
 namespace datapath {
 	class iserver {
-		virtual datapath::error accept(std::shared_ptr<datapath::isocket>& socket) = 0;
+		public /*event*/:
 
+		/** Accepted Connection Event
+		 * This event is called if a new connection is pending evaluation. 
+		 * 
+		 * @param bool& Set to true to accept, false to decline.
+		 * @param std::shared_ptr<datapath::isocket> Socket.
+		 * @return void
+		 */
+		datapath::event<bool&, std::shared_ptr<datapath::isocket>> on_accept;
+
+		public:
 		virtual datapath::error close() = 0;
 	};
 } // namespace datapath

source/windows/server.cpp

@@ -94,22 +94,18 @@ void datapath::windows::server::_watcher()
 	std::map<HANDLE, std::shared_ptr<datapath::windows::overlapped>> ovmap;
 
 	while (!this->watcher.shutdown) {
-		// Verify existing connections.
-		{
-			std::unique_lock<std::mutex> ul(this->lock);
-			for (auto itr = this->active_sockets.begin(); itr != this->active_sockets.end(); itr++) {
-				if (itr->second.expired()) {
-					this->active_sockets.erase(itr);
-					this->waiting_sockets.push_back(itr->first);
-					continue;
-				}
-				auto obj = itr->second.lock();
-				if (!obj->good()) {
-					this->active_sockets.erase(itr);
-					this->waiting_sockets.push_back(itr->first);
-					continue;
-				}
+		// Wait for any overlapped objects.
+		if (ovmap.size() > 0) {
+			// No lock as we aren't touching any list or map yet.
+			std::vector<datapath::waitable*> waits;
+			waits.reserve(ovmap.size());
+
+			for (auto kv : ovmap) {
+				waits.push_back(&(*kv.second));
 			}
+
+			size_t          index = 0;
+			datapath::error ec = datapath::waitable::wait_any(waits, index, std::chrono::milliseconds(1));
 		}
 
 		// Update list of overlappeds to track.
@@ -136,26 +132,87 @@ void datapath::windows::server::_watcher()
 			}
 		}
 
-		// Wait for any overlapped objects.
-		if (ovmap.size() > 0) {
-			// No lock as we aren't touching any list or map yet.
-			std::vector<datapath::waitable*> waits;
-			waits.reserve(ovmap.size());
+		// Notify of pending sockets.
+		{
+			std::unique_lock<std::mutex> ul(this->lock);
+			if (this->on_accept) {
+				for (auto itr = this->pending_sockets.begin(); itr != this->pending_sockets.end();
+				     itr++) {
+					bool accept = true;
 
-			for (auto kv : ovmap) {
-				waits.push_back(&(*kv.second));
+					auto sock = std::make_shared<datapath::windows::socket>();
+					sock->_connect(*itr);
+
+					auto isock = std::dynamic_pointer_cast<datapath::isocket>(sock);
+					this->on_accept(accept, isock);
+
+					if (accept) {
+						this->pending_sockets.erase(itr);
+						this->active_sockets.insert({*itr, sock});
+
+						if ((this->waiting_sockets.size() + this->pending_sockets.size())
+						    < WIN_BACKLOG_NUM) {
+							if ((this->sockets.size() <= this->max_clients)
+							    && (this->max_clients > 0)) {
+								HANDLE handle = _create_socket(this->path, false);
+								if (handle != INVALID_HANDLE_VALUE) {
+									this->sockets.push_back(handle);
+									this->waiting_sockets.push_back(handle);
+								}
+							}
+						}
+					} else {
+						// Force close and return to waiting.
+						sock->close();
+						this->pending_sockets.erase(itr);
+						this->waiting_sockets.push_back(*itr);
+					}
+				}
 			}
+		}
 
-			size_t          index = 0;
-			datapath::error ec = datapath::waitable::wait_any(waits, index, std::chrono::milliseconds(1));
-		} else {
+		// Verify existing connections.
+		{
+			std::unique_lock<std::mutex> ul(this->lock);
+			for (auto itr = this->active_sockets.begin(); itr != this->active_sockets.end(); itr++) {
+				if (itr->second.expired()) {
+					// Enforce backlog size
+					if ((this->waiting_sockets.size() + this->pending_sockets.size())
+					    < WIN_BACKLOG_NUM) {
+						this->waiting_sockets.push_back(itr->first);
+					} else {
+						DisconnectNamedPipe(itr->first);
+						CloseHandle(itr->first);
+						this->sockets.remove(itr->first);
+					}
+					this->active_sockets.erase(itr);
+					continue;
+				}
+				auto obj = itr->second.lock();
+				if (!obj->good()) {
+					// Enforce backlog size
+					if ((this->waiting_sockets.size() + this->pending_sockets.size())
+					    < WIN_BACKLOG_NUM) {
+						this->waiting_sockets.push_back(itr->first);
+					} else {
+						DisconnectNamedPipe(itr->first);
+						CloseHandle(itr->first);
+						this->sockets.remove(itr->first);
+					}
+					this->active_sockets.erase(itr);
+					continue;
+				}
+			}
+		}
+
+		if (ovmap.size() == 0) {
 			// Just sleep 1ms to not use too much CPU.
 			std::this_thread::sleep_for(std::chrono::milliseconds(1));
 		}
 	}
 }
 
-datapath::error datapath::windows::server::accept(std::shared_ptr<datapath::isocket>& socket)
+/*datapath::error datapath::windows::server::accept(std::shared_ptr<datapath::isocket>& socket)
 {
 	std::unique_lock<std::mutex> ul(this->lock);
 	if (this->pending_sockets.size() == 0) {
@@ -185,7 +242,7 @@ datapath::error datapath::windows::server::accept(std::shared_ptr<datapath::isoc
 
 	this->active_sockets.insert({handle, socket});
 	return datapath::error::Success;
-}
+}*/
 
 datapath::error datapath::windows::server::close()
 {

source/windows/server.hpp

@@ -31,7 +31,7 @@ extern "C" {
 
 namespace datapath {
 	namespace windows {
-		class server : public iserver {
+		class server : public iserver, public std::enable_shared_from_this<datapath::windows::server> {
 			bool        is_created  = false;
 			size_t      max_clients = -1;
 			std::string path;
@@ -61,8 +61,6 @@ namespace datapath {
 			void _watcher();
 
 			public /*virtual override*/:
-			virtual datapath::error accept(std::shared_ptr<datapath::isocket>& socket) override;
-
 			virtual datapath::error close() override;
 
 			public: