Refactor server code

Split callback logic into several functions.

CMakeLists.txt

@@ -173,7 +173,7 @@ add_executable(
     src/packages/server/log/IZ_log.h
     src/packages/server/log/IZ_log.c
     src/packages/server/main.c
-        src/packages/server/protocol_lws_minimal.c src/packages/server/IZ_app.c src/packages/server/IZ_app.h src/packages/server/network/IZ_wsserver.c src/packages/server/network/IZ_wsserver.h)
+        src/packages/server/network/IZ_wsserver.c src/packages/server/IZ_app.c src/packages/server/IZ_app.h src/packages/server/network/IZ_wsserver.h)
 
 target_link_libraries(
   server

src/packages/game/IZ_app.c

@@ -28,7 +28,7 @@ IZ_ProcedureResult IZ_AppWSClientCallback(
 	return 0;
 }
 
-IZ_ProcedureResult IZ_AppInitialize(IZ_App* app) {
+IZ_ProcedureResult IZ_AppInitialize(IZ_App* app, u8 argc, const char* argv[]) {
 	memset(app, 0, sizeof(IZ_App));
 	u32 flags = (
 		SDL_INIT_VIDEO
@@ -37,13 +37,19 @@ IZ_ProcedureResult IZ_AppInitialize(IZ_App* app) {
 	);
 
 	if (SDL_Init(flags) < 0) {
-		// TODO fix logging
 		SDL_LogError(SDL_LOG_CATEGORY_ERROR, "SDL could not initialize! SDL_Error: %s\n", SDL_GetError());
 		return IZ_APP_RUN_SDL_INIT_ERROR;
 	}
 
+	const char* cmdline_buffer;
 	char config_path[128];
-	IZ_ConfigGetPath(config_path, 128);
+	// TODO abstract command line args parsing
+	if ((cmdline_buffer = lws_cmdline_option(argc, argv, "-c"))) {
+		memcpy_s(config_path, 128, cmdline_buffer, 128);
+	} else {
+		IZ_ConfigGetDefaultPath(config_path, 128);
+	}
+
 	if (IZ_VideoInitialize(&app->video_state, config_path)) {
 		return IZ_APP_RUN_VIDEO_INIT_ERROR;
 	}
@@ -131,13 +137,7 @@ IZ_ProcedureResult IZ_AppRunNetworkingThread(void* ptr) {
 }
 
 IZ_ProcedureResult IZ_AppRun(IZ_App* app, u8 argc, const char* argv[]) {
-	printf_s("Args (%u):\n", argc);
-	u8 arg_index;
-	for (arg_index = 0; arg_index < argc; arg_index += 1) {
-		printf_s("  %s\n", argv[arg_index]);
-	}
-
-	IZ_ProcedureResult init_result = IZ_AppInitialize(app);
+	IZ_ProcedureResult init_result = IZ_AppInitialize(app, argc, argv);
 	if (init_result) {
 		return init_result;
 	}

src/packages/game/IZ_app.h

@@ -2,11 +2,7 @@
 #define IZ_APP_H
 
 #include <SDL.h>
-#ifdef __WIN32__
-#include <getopt.h>
-#else
-#include <unistd.h>
-#endif
+#include <libwebsockets.h>
 #include "input/IZ_input.h"
 #include "output/IZ_video.h"
 #include "memory/IZ_pool.h"

src/packages/game/IZ_config.c

@@ -1,6 +1,6 @@
 #include "IZ_config.h"
 
-void IZ_ConfigGetPath(char* config_path, size_t string_size) {
+void IZ_ConfigGetDefaultPath(const char* config_path, size_t string_size) {
 	//const char* config_path_dir = SDL_GetPrefPath("Modal Studios", APP_NAME);
 	const char* config_path_dir = SDL_GetBasePath();
 	memcpy_s(config_path, string_size, config_path_dir, 128);

src/packages/game/IZ_config.h

@@ -4,6 +4,6 @@
 #include <SDL_filesystem.h>
 #include <string.h>
 
-void IZ_ConfigGetPath(char*, size_t);
+void IZ_ConfigGetDefaultPath(const char*, size_t);
 
 #endif

src/packages/game/memory/IZ_pool.h

@@ -5,7 +5,7 @@
 #include "../IZ_common.h"
 #include "../data/IZ_list.h"
 
-#define POOL_MAX_SIZE (1l << 23) // 16MB
+#define POOL_MAX_SIZE (1llu << 23) // 16MB
 
 struct IZ_Pool;
 

src/packages/server/IZ_app.c

@@ -1,24 +1,75 @@
 #include "IZ_app.h"
 
+static struct lws_protocols protocols[] = {
+	{
+		.name = NETWORK_PROTOCOL,
+		.callback = IZ_WSServerCallback,
+		.per_session_data_size = sizeof(IZ_WSServerSessionData),
+		.rx_buffer_size = 0,
+		.id = 0,
+		.user = NULL,
+		.tx_packet_size = 0,
+	},
+	{
+		.name = "http",
+		.callback = lws_callback_http_dummy,
+		.per_session_data_size = 0,
+		.rx_buffer_size = 0,
+		.id = 0,
+		.user = NULL,
+		.tx_packet_size = 0,
+	},
+	LWS_PROTOCOL_LIST_TERM,
+};
+
+static const struct lws_http_mount mount = {
+	.mount_next = NULL,    /* linked-list "next" */
+	.mountpoint = "/",    /* mountpoint URL */
+	.origin = "./mount-origin", /* serve from dir */
+	.def = "index.html",  /* default filename */
+	.protocol = NULL,
+	.cgienv = NULL,
+	.extra_mimetypes = NULL,
+	.interpret = NULL,
+	.cgi_timeout = 0,
+	.cache_max_age = 0,
+	.auth_mask = 0,
+	.cache_reusable = 0,
+	.cache_revalidate = 0,
+	.cache_intermediaries = 0,
+	.origin_protocol = LWSMPRO_FILE,  /* files in a dir */
+	.mountpoint_len = 1,    /* char count */
+	.basic_auth_login_file = NULL,
+};
+
 void IZ_AppHandleSignal(i32 _signal) {
 	interrupted = true;
 }
 
-void IZ_AppCreateContext(IZ_App* app) {
+IZ_ProcedureResult IZ_AppCreateContext(IZ_App *app) {
 	struct lws_context_creation_info info;
 	memset(&info, 0, sizeof info);
 	info.port = app->config.port;
+	info.mounts = &mount;
+	info.protocols = protocols;
 	// TODO initialize protocols
 	info.options = (
 		LWS_SERVER_OPTION_VALIDATE_UTF8
 		| LWS_SERVER_OPTION_HTTP_HEADERS_SECURITY_BEST_PRACTICES_ENFORCE
 	);
+
+	app->context = lws_create_context(&info);
+	if (!app->context) {
+		return 1;
+	}
+
+	return 0;
 }
 
-void IZ_AppLoadConfig(IZ_App* app, u8 argc, const char** argv) {
+void IZ_AppLoadConfig(IZ_App *app, u8 argc, const char **argv) {
 	memcpy_s(app, sizeof(IZ_App), &IZ_APP_DEFAULT_STATE, sizeof(IZ_App));
 
-	const char* cmdline_buffer;
+	const char *cmdline_buffer;
 	if ((cmdline_buffer = lws_cmdline_option(argc, argv, "-d"))) {
 		app->config.log_level = atoi(cmdline_buffer);
 	}
@@ -37,21 +88,29 @@ void IZ_AppLoadConfig(IZ_App* app, u8 argc, const char** argv) {
 	}
 }
 
-IZ_ProcedureResult IZ_AppInitialize(IZ_App* app, u8 argc, const char** argv) {
+IZ_ProcedureResult IZ_AppInitialize(IZ_App *app, u8 argc, const char **argv) {
 	interrupted = false;
 	signal(SIGINT, IZ_AppHandleSignal);
 
 	IZ_AppLoadConfig(app, argc, argv);
 	IZ_LogInterceptWSMessages(app->config.log_level);
-	IZ_AppCreateContext(app);
+	if (IZ_AppCreateContext(app)) {
+		return 1;
+	}
 
 	return 0;
 }
 
-IZ_ProcedureResult IZ_AppRun(IZ_App* app, u8 argc, const char** argv) {
+IZ_ProcedureResult IZ_AppRun(IZ_App *app, u8 argc, const char **argv) {
 	if (IZ_AppInitialize(app, argc, argv)) {
 		return 1;
 	}
 
+	i32 n = 0;
+	while (n >= 0 && !interrupted) {
+		n = lws_service(app->context, 0);
+	}
+
+	lws_context_destroy(app->context);
 	return 0;
 }

src/packages/server/IZ_app.h

@@ -3,9 +3,9 @@
 
 #include <signal.h>
 #include <stdbool.h>
-#include <libwebsockets.h>
-#include "IZ_common.h"
+#include "network/IZ_wsserver.h"
 #include "log/IZ_log.h"
+#include "IZ_common.h"
 
 static bool interrupted;
 

src/packages/server/main.c

@@ -1,84 +1,6 @@
-#include <libwebsockets.h>
-#include <string.h>
-#include <signal.h>
+#include "IZ_app.h"
 
-#include "IZ_common.h"
-#include "log/IZ_log.h"
-
-#define LWS_PLUGIN_STATIC
-#include "protocol_lws_minimal.c"
-
-static struct lws_protocols protocols[] = {
-	//{ "http", lws_callback_http_dummy, 0, 0, 0, NULL, 0 },
-	LWS_PLUGIN_PROTOCOL_MINIMAL,
-	LWS_PROTOCOL_LIST_TERM
-};
-
-static int interrupted;
-
-static const struct lws_http_mount mount = {
-	/* .mount_next */		NULL,		/* linked-list "next" */
-	/* .mountpoint */		"/",		/* mountpoint URL */
-	/* .origin */			"./mount-origin", /* serve from dir */
-	/* .def */			"index.html",	/* default filename */
-	/* .protocol */			NULL,
-	/* .cgienv */			NULL,
-	/* .extra_mimetypes */		NULL,
-	/* .interpret */		NULL,
-	/* .cgi_timeout */		0,
-	/* .cache_max_age */		0,
-	/* .auth_mask */		0,
-	/* .cache_reusable */		0,
-	/* .cache_revalidate */		0,
-	/* .cache_intermediaries */	0,
-	/* .origin_protocol */		LWSMPRO_FILE,	/* files in a dir */
-	/* .mountpoint_len */		1,		/* char count */
-	/* .basic_auth_login_file */	NULL,
-};
-
-void sigint_handler(int sig)
-{
-	interrupted = 1;
-}
-
-int main(int argc, const char **argv)
-{
-	struct lws_context_creation_info info;
-	struct lws_context *context;
-	const char *p;
-	int n = 0, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE
-	/* for LLL_ verbosity above NOTICE to be built into lws,
-	 * lws must have been configured and built with
-	 * -DCMAKE_BUILD_TYPE=DEBUG instead of =RELEASE */
-	/* | LLL_INFO */ /* | LLL_PARSER */ /* | LLL_HEADER */
-	/* | LLL_EXT */ /* | LLL_CLIENT */ /* | LLL_LATENCY */
-	/* | LLL_DEBUG */;
-
-	signal(SIGINT, sigint_handler);
-
-	if ((p = lws_cmdline_option(argc, argv, "-d")))
-		logs = atoi(p);
-
-	IZ_LogInterceptWSMessages(logs);
-	lwsl_user("LWS minimal ws server (lws_ring) | visit http://localhost:7681\n");
-
-	memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
-	info.port = 42069;
-	info.mounts = &mount;
-	info.protocols = protocols;
-	info.options =
-		LWS_SERVER_OPTION_HTTP_HEADERS_SECURITY_BEST_PRACTICES_ENFORCE;
-
-	context = lws_create_context(&info);
-	if (!context) {
-		lwsl_err("lws init failed\n");
-		return 1;
-	}
-
-	while (n >= 0 && !interrupted)
-		n = lws_service(context, 0);
-
-	lws_context_destroy(context);
-
-	return 0;
+IZ_ProcedureResult main(i32 argc, const char *argv[]) {
+	IZ_App app;
+	return IZ_AppRun(&app, argc, argv);
 }

src/packages/server/network/IZ_wsserver.c

@@ -1 +1,285 @@
 #include "IZ_wsserver.h"
+
+/* one of these created for each message */
+
+static void IZ_ProtocolCullLaggingClients(IZ_WSServerVHostData *vhd) {
+	u32 oldest_tail = lws_ring_get_oldest_tail(vhd->ring);
+	IZ_WSServerSessionData *old_pss = NULL;
+	i32 most = 0;
+	i32 before = (i32) lws_ring_get_count_waiting_elements(vhd->ring, &oldest_tail);
+	i32 m;
+
+	/*
+	 * At least one guy with the oldest tail has lagged too far, filling
+	 * the ringbuffer with stuff waiting for them, while new stuff is
+	 * coming in, and they must close, freeing up ringbuffer entries.
+	 */
+
+	lws_start_foreach_llp_safe(
+		IZ_WSServerSessionData**,
+		ppss,
+		vhd->pss_list,
+		pss_list
+	) {
+		if ((*ppss)->tail == oldest_tail) {
+			old_pss = *ppss;
+
+			lwsl_user("Killing lagging client %p\n", (*ppss)->wsi);
+
+			lws_set_timeout((*ppss)->wsi, PENDING_TIMEOUT_LAGGING,
+				/*
+				 * we may kill the wsi we came in on,
+				 * so the actual close is deferred
+				 */
+											LWS_TO_KILL_ASYNC);
+
+			/*
+			 * We might try to write something before we get a
+			 * chance to close.  But this pss is now detached
+			 * from the ring buffer.  Mark this pss as culled so we
+			 * don't try to do anything more with it.
+			 */
+
+			(*ppss)->culled = true;
+
+			/*
+			 * Because we can't kill it synchronously, but we
+			 * know it's closing momentarily and don't want its
+			 * participation any more, remove its pss from the
+			 * vhd pss list early.  (This is safe to repeat
+			 * uselessly later in the close flow).
+			 *
+			 * Notice this changes *ppss!
+			 */
+
+			lws_ll_fwd_remove(IZ_WSServerSessionData, pss_list, (*ppss), vhd->pss_list);
+
+			/* use the changed *ppss so we won't skip anything */
+
+			continue;
+		}
+
+		/*
+		 * so this guy is a survivor of the cull.  Let's track
+		 * what is the largest number of pending ring elements
+		 * for any survivor.
+		 */
+		m = (i32) lws_ring_get_count_waiting_elements(vhd->ring, &((*ppss)->tail));
+		if (m > most) {
+			most = m;
+		}
+	} lws_end_foreach_llp_safe(ppss);
+
+	/* it would mean we lost track of oldest... but Coverity insists */
+	if (!old_pss) {
+		return;
+	}
+
+	/*
+	 * Let's recover (ie, free up) all the ring slots between the
+	 * original oldest's last one and the "worst" survivor.
+	 */
+
+	lws_ring_consume_and_update_oldest_tail(
+		vhd->ring,
+		IZ_WSServerSessionData,
+		&old_pss->tail,
+		(size_t) (before - most),
+		vhd->pss_list,
+		tail,
+		pss_list
+	);
+
+	lwsl_user("%s: shrunk ring from %d to %d\n", __func__, before, most);
+}
+
+/* destroys the message when everyone has had a copy of it */
+
+void IZ_ProtocolDestroyMessage(void *_msg) {
+	IZ_WSServerMessage *msg = _msg;
+
+	free(msg->payload);
+	msg->payload = NULL;
+	msg->len = 0;
+}
+
+i32 IZ_WSServerInitialize(struct lws* wsi) {
+	IZ_WSServerVHostData* vhd_instance = (IZ_WSServerVHostData*) lws_protocol_vh_priv_get(
+		lws_get_vhost(wsi),
+		lws_get_protocol(wsi)
+	);
+	IZ_WSServerVHostData** vhd = &vhd_instance;
+	*vhd = lws_protocol_vh_priv_zalloc(
+		lws_get_vhost(wsi),
+		lws_get_protocol(wsi),
+		sizeof(IZ_WSServerVHostData)
+	);
+	(*vhd)->context = lws_get_context(wsi);
+	(*vhd)->protocol = lws_get_protocol(wsi);
+	(*vhd)->vhost = lws_get_vhost(wsi);
+	(*vhd)->ring = lws_ring_create(
+		sizeof(IZ_WSServerMessage),
+		RING_COUNT,
+		IZ_ProtocolDestroyMessage
+	);
+	if (!(*vhd)->ring) {
+		return 1;
+	}
+	return 0;
+}
+
+void IZ_WSServerTeardown(struct lws* wsi) {
+	IZ_WSServerVHostData* vhd = (IZ_WSServerVHostData*) lws_protocol_vh_priv_get(
+		lws_get_vhost(wsi),
+		lws_get_protocol(wsi)
+	);
+	lws_ring_destroy(vhd->ring);
+}
+
+void IZ_WSServerOnOpen(struct lws* wsi, IZ_WSServerSessionData* pss) {
+	IZ_WSServerVHostData* vhd = (IZ_WSServerVHostData*) lws_protocol_vh_priv_get(
+		lws_get_vhost(wsi),
+		lws_get_protocol(wsi)
+	);
+
+	/* add ourselves to the list of live pss held in the vhd */
+	lwsl_user("LWS_CALLBACK_ESTABLISHED: wsi %p\n", wsi);
+	lws_ll_fwd_insert(pss, pss_list, vhd->pss_list);
+	pss->tail = lws_ring_get_oldest_tail(vhd->ring);
+	pss->wsi = wsi;
+}
+
+void IZ_WSServerOnClose(struct lws* wsi, IZ_WSServerSessionData* pss) {
+	IZ_WSServerVHostData* vhd = (IZ_WSServerVHostData*) lws_protocol_vh_priv_get(
+		lws_get_vhost(wsi),
+		lws_get_protocol(wsi)
+	);
+
+	lwsl_user("LWS_CALLBACK_CLOSED: wsi %p\n", wsi);
+	/* remove our closing pss from the list of live pss */
+	lws_ll_fwd_remove(IZ_WSServerSessionData, pss_list, pss, vhd->pss_list);
+}
+
+IZ_ProcedureResult IZ_WSServerOnSend(struct lws* wsi, IZ_WSServerSessionData* pss) {
+	IZ_WSServerVHostData* vhd = (IZ_WSServerVHostData*) lws_protocol_vh_priv_get(
+		lws_get_vhost(wsi),
+		lws_get_protocol(wsi)
+	);
+
+	if (pss->culled) {
+		return 0;
+	}
+	const IZ_WSServerMessage *pmsg = lws_ring_get_element(vhd->ring, &pss->tail);
+	if (!pmsg) {
+		return 0;
+	}
+
+	/* notice we allowed for LWS_PRE in the payload already */
+	i32 m = lws_write(
+		wsi,
+		((unsigned char *) pmsg->payload) + LWS_PRE,
+		pmsg->len,
+		pmsg->binary ? LWS_WRITE_BINARY : LWS_WRITE_TEXT
+	);
+
+	if (m < (i32) pmsg->len) {
+		lwsl_err("ERROR %d writing to ws socket\n", m);
+		return -1;
+	}
+
+	lws_ring_consume_and_update_oldest_tail(
+		vhd->ring,  /* lws_ring object */
+		IZ_WSServerSessionData, /* type of objects with tails */
+		&pss->tail,  /* tail of guy doing the consuming */
+		1,    /* number of payload objects being consumed */
+		vhd->pss_list,  /* head of list of objects with tails */
+		tail,    /* member name of tail in objects with tails */
+		pss_list  /* member name of next object in objects with tails */
+	);
+
+	/* more to do for us? */
+	if (lws_ring_get_element(vhd->ring, &pss->tail)) {
+		/* come back as soon as we can write more */
+		lws_callback_on_writable(pss->wsi);
+	}
+
+	return 0;
+}
+
+void IZ_WSServerOnReceive(struct lws* wsi, void* in, size_t len) {
+	IZ_WSServerVHostData* vhd = (IZ_WSServerVHostData*) lws_protocol_vh_priv_get(
+		lws_get_vhost(wsi),
+		lws_get_protocol(wsi)
+	);
+	IZ_WSServerMessage amsg;
+	i32 n = (i32) lws_ring_get_count_free_elements(vhd->ring);
+	if (!n) {
+		/* forcibly make space */
+		IZ_ProtocolCullLaggingClients(vhd);
+		n = (i32) lws_ring_get_count_free_elements(vhd->ring);
+	}
+
+	if (!n) {
+		return;
+	}
+
+	lwsl_user("LWS_CALLBACK_RECEIVE: free space %d\n", n);
+
+	amsg.len = len;
+	/* notice we over-allocate by LWS_PRE... */
+	amsg.payload = malloc(LWS_PRE + len);
+	amsg.binary = (u8) lws_frame_is_binary(wsi);
+	if (!amsg.payload) {
+		lwsl_user("OOM: dropping\n");
+		return;
+	}
+
+	/* ...and we copy the payload in at +LWS_PRE */
+	memcpy((char *) amsg.payload + LWS_PRE, in, len);
+	if (!lws_ring_insert(vhd->ring, &amsg, 1)) {
+		IZ_ProtocolDestroyMessage(&amsg);
+		lwsl_user("dropping!\n");
+		return;
+	}
+
+	/*
+	 * let everybody know we want to write something on them
+	 * as soon as they are ready
+	 */
+	lws_start_foreach_llp(IZ_WSServerSessionData**, ppss, vhd->pss_list) {
+		lws_callback_on_writable((*ppss)->wsi);
+	}
+
+	lws_end_foreach_llp(ppss, pss_list);
+}
+
+i32 IZ_WSServerCallback(
+	struct lws* wsi,
+	enum lws_callback_reasons reason,
+	void* user,
+	void* in,
+	size_t len
+) {
+	switch (reason) {
+		case LWS_CALLBACK_PROTOCOL_INIT:
+			return IZ_WSServerInitialize(wsi);
+		case LWS_CALLBACK_PROTOCOL_DESTROY:
+			IZ_WSServerTeardown(wsi);
+			break;
+		case LWS_CALLBACK_ESTABLISHED:
+			IZ_WSServerOnOpen(wsi, user);
+			break;
+		case LWS_CALLBACK_CLOSED:
+			IZ_WSServerOnClose(wsi, user);
+			break;
+		case LWS_CALLBACK_SERVER_WRITEABLE:
+			return IZ_WSServerOnSend(wsi, user);
+		case LWS_CALLBACK_RECEIVE:
+			IZ_WSServerOnReceive(wsi, in, len);
+			break;
+		default:
+			break;
+	}
+
+	return 0;
+}

src/packages/server/network/IZ_wsserver.h

@@ -1,4 +1,45 @@
 #ifndef IZ_WSSERVER_H
 #define IZ_WSSERVER_H
 
+#include "libwebsockets.h"
+#include <string.h>
+#include "../IZ_common.h"
+
+#define RING_COUNT 32
+
+typedef struct {
+	void *payload; /* is malloc'd */
+	size_t len;
+	u8 binary: 1;
+} IZ_WSServerMessage;
+
+/* one of these is created for each client connecting to us */
+
+typedef struct IZ_WSServerSessionData {
+	struct IZ_WSServerSessionData *pss_list;
+	struct lws *wsi;
+	u32 tail;
+	u8 culled: 1;
+} IZ_WSServerSessionData;
+
+/* one of these is created for each vhost our protocol is used with */
+
+typedef struct {
+	struct lws_context *context;
+	struct lws_vhost *vhost;
+	const struct lws_protocols *protocol;
+
+	IZ_WSServerSessionData *pss_list; /* linked-list of live pss*/
+
+	struct lws_ring *ring; /* ringbuffer holding unsent messages */
+} IZ_WSServerVHostData;
+
+i32 IZ_WSServerCallback(
+	struct lws*,
+	enum lws_callback_reasons,
+	void*,
+	void*,
+	size_t
+);
+
 #endif

src/packages/server/protocol_lws_minimal.c

@@ -1,268 +0,0 @@
-#if !defined (LWS_PLUGIN_STATIC)
-#define LWS_DLL
-#define LWS_INTERNAL
-#include <libwebsockets.h>
-#endif
-
-#include <string.h>
-#include "IZ_common.h"
-
-#define RING_COUNT 32
-/* one of these created for each message */
-
-struct msg {
-	void *payload; /* is malloc'd */
-	size_t len;
-};
-
-/* one of these is created for each client connecting to us */
-
-struct per_session_data__minimal {
-	struct per_session_data__minimal *pss_list;
-	struct lws *wsi;
-	uint32_t tail;
-
-	unsigned int culled:1;
-};
-
-/* one of these is created for each vhost our protocol is used with */
-
-struct per_vhost_data__minimal {
-	struct lws_context *context;
-	struct lws_vhost *vhost;
-	const struct lws_protocols *protocol;
-
-	struct per_session_data__minimal *pss_list; /* linked-list of live pss*/
-
-	struct lws_ring *ring; /* ringbuffer holding unsent messages */
-};
-
-static void
-cull_lagging_clients(struct per_vhost_data__minimal *vhd)
-{
-	uint32_t oldest_tail = lws_ring_get_oldest_tail(vhd->ring);
-	struct per_session_data__minimal *old_pss = NULL;
-	int most = 0, before = (int)lws_ring_get_count_waiting_elements(vhd->ring,
-																																	&oldest_tail), m;
-
-	/*
-	 * At least one guy with the oldest tail has lagged too far, filling
-	 * the ringbuffer with stuff waiting for them, while new stuff is
-	 * coming in, and they must close, freeing up ringbuffer entries.
-	 */
-
-	lws_start_foreach_llp_safe(struct per_session_data__minimal **,
-														 ppss, vhd->pss_list, pss_list) {
-
-				if ((*ppss)->tail == oldest_tail) {
-					old_pss = *ppss;
-
-					lwsl_user("Killing lagging client %p\n", (*ppss)->wsi);
-
-					lws_set_timeout((*ppss)->wsi, PENDING_TIMEOUT_LAGGING,
-						/*
-						 * we may kill the wsi we came in on,
-						 * so the actual close is deferred
-						 */
-													LWS_TO_KILL_ASYNC);
-
-					/*
-					 * We might try to write something before we get a
-					 * chance to close.  But this pss is now detached
-					 * from the ring buffer.  Mark this pss as culled so we
-					 * don't try to do anything more with it.
-					 */
-
-					(*ppss)->culled = 1;
-
-					/*
-					 * Because we can't kill it synchronously, but we
-					 * know it's closing momentarily and don't want its
-					 * participation any more, remove its pss from the
-					 * vhd pss list early.  (This is safe to repeat
-					 * uselessly later in the close flow).
-					 *
-					 * Notice this changes *ppss!
-					 */
-
-					lws_ll_fwd_remove(struct per_session_data__minimal,
-														pss_list, (*ppss), vhd->pss_list);
-
-					/* use the changed *ppss so we won't skip anything */
-
-					continue;
-
-				} else {
-					/*
-					 * so this guy is a survivor of the cull.  Let's track
-					 * what is the largest number of pending ring elements
-					 * for any survivor.
-					 */
-					m = (int)lws_ring_get_count_waiting_elements(vhd->ring,
-																											 &((*ppss)->tail));
-					if (m > most)
-						most = m;
-				}
-
-			} lws_end_foreach_llp_safe(ppss);
-
-	/* it would mean we lost track of oldest... but Coverity insists */
-	if (!old_pss)
-		return;
-
-	/*
-	 * Let's recover (ie, free up) all the ring slots between the
-	 * original oldest's last one and the "worst" survivor.
-	 */
-
-	lws_ring_consume_and_update_oldest_tail(vhd->ring,
-																					struct per_session_data__minimal, &old_pss->tail, (size_t)(before - most),
-																					vhd->pss_list, tail, pss_list);
-
-	lwsl_user("%s: shrunk ring from %d to %d\n", __func__, before, most);
-}
-
-/* destroys the message when everyone has had a copy of it */
-
-static void
-__minimal_destroy_message(void *_msg)
-{
-	struct msg *msg = _msg;
-
-	free(msg->payload);
-	msg->payload = NULL;
-	msg->len = 0;
-}
-
-static int
-callback_minimal(struct lws *wsi, enum lws_callback_reasons reason,
-								 void *user, void *in, size_t len)
-{
-	struct per_session_data__minimal *pss =
-		(struct per_session_data__minimal *)user;
-	struct per_vhost_data__minimal *vhd =
-		(struct per_vhost_data__minimal *)
-			lws_protocol_vh_priv_get(lws_get_vhost(wsi),
-															 lws_get_protocol(wsi));
-	const struct msg *pmsg;
-	struct msg amsg;
-	int n, m;
-
-	switch (reason) {
-		case LWS_CALLBACK_PROTOCOL_INIT:
-			vhd = lws_protocol_vh_priv_zalloc(lws_get_vhost(wsi),
-																				lws_get_protocol(wsi),
-																				sizeof(struct per_vhost_data__minimal));
-			vhd->context = lws_get_context(wsi);
-			vhd->protocol = lws_get_protocol(wsi);
-			vhd->vhost = lws_get_vhost(wsi);
-
-			vhd->ring = lws_ring_create(sizeof(struct msg), RING_COUNT,
-																	__minimal_destroy_message);
-			if (!vhd->ring)
-				return 1;
-			break;
-
-		case LWS_CALLBACK_PROTOCOL_DESTROY:
-			lws_ring_destroy(vhd->ring);
-			break;
-
-		case LWS_CALLBACK_ESTABLISHED:
-			/* add ourselves to the list of live pss held in the vhd */
-			lwsl_user("LWS_CALLBACK_ESTABLISHED: wsi %p\n", wsi);
-			lws_ll_fwd_insert(pss, pss_list, vhd->pss_list);
-			pss->tail = lws_ring_get_oldest_tail(vhd->ring);
-			pss->wsi = wsi;
-			break;
-
-		case LWS_CALLBACK_CLOSED:
-			lwsl_user("LWS_CALLBACK_CLOSED: wsi %p\n", wsi);
-			/* remove our closing pss from the list of live pss */
-			lws_ll_fwd_remove(struct per_session_data__minimal, pss_list,
-												pss, vhd->pss_list);
-			break;
-
-		case LWS_CALLBACK_SERVER_WRITEABLE:
-			if (pss->culled)
-				break;
-			pmsg = lws_ring_get_element(vhd->ring, &pss->tail);
-			if (!pmsg)
-				break;
-
-			/* notice we allowed for LWS_PRE in the payload already */
-			m = lws_write(wsi, ((unsigned char *)pmsg->payload) +
-												 LWS_PRE, pmsg->len, LWS_WRITE_TEXT);
-			if (m < (int)pmsg->len) {
-				lwsl_err("ERROR %d writing to ws socket\n", m);
-				return -1;
-			}
-
-			lws_ring_consume_and_update_oldest_tail(
-				vhd->ring,	/* lws_ring object */
-				struct per_session_data__minimal, /* type of objects with tails */
-				&pss->tail,	/* tail of guy doing the consuming */
-				1,		/* number of payload objects being consumed */
-				vhd->pss_list,	/* head of list of objects with tails */
-				tail,		/* member name of tail in objects with tails */
-				pss_list	/* member name of next object in objects with tails */
-			);
-
-			/* more to do for us? */
-			if (lws_ring_get_element(vhd->ring, &pss->tail))
-				/* come back as soon as we can write more */
-				lws_callback_on_writable(pss->wsi);
-			break;
-
-		case LWS_CALLBACK_RECEIVE:
-			n = (int)lws_ring_get_count_free_elements(vhd->ring);
-			if (!n) {
-				/* forcibly make space */
-				cull_lagging_clients(vhd);
-				n = (int)lws_ring_get_count_free_elements(vhd->ring);
-			}
-			if (!n)
-				break;
-
-			lwsl_user("LWS_CALLBACK_RECEIVE: free space %d\n", n);
-
-			amsg.len = len;
-			/* notice we over-allocate by LWS_PRE... */
-			amsg.payload = malloc(LWS_PRE + len);
-			if (!amsg.payload) {
-				lwsl_user("OOM: dropping\n");
-				break;
-			}
-
-			/* ...and we copy the payload in at +LWS_PRE */
-			memcpy((char *)amsg.payload + LWS_PRE, in, len);
-			if (!lws_ring_insert(vhd->ring, &amsg, 1)) {
-				__minimal_destroy_message(&amsg);
-				lwsl_user("dropping!\n");
-				break;
-			}
-
-			/*
-			 * let everybody know we want to write something on them
-			 * as soon as they are ready
-			 */
-			lws_start_foreach_llp(struct per_session_data__minimal **,
-														ppss, vhd->pss_list) {
-						lws_callback_on_writable((*ppss)->wsi);
-					} lws_end_foreach_llp(ppss, pss_list);
-			break;
-
-		default:
-			break;
-	}
-
-	return 0;
-}
-
-#define LWS_PLUGIN_PROTOCOL_MINIMAL \
-        { \
-                NETWORK_PROTOCOL, \
-                callback_minimal, \
-                sizeof(struct per_session_data__minimal), \
-                0, \
-                0, NULL, 0 \
-        }