Updated ELM327-plugin, added Makefile

- ELM327-Plugin now works properly and with higher polling-speed
- added makefile for easier compilation (no cross-compilation for now)
- fixed incorrect dpi calculation

Author: ardera

.gitignore

@@ -1,3 +1,3 @@
 out
 .vscode
-Makefile
+build.sh

Makefile

@@ -0,0 +1,21 @@
+CC = cc
+LD = cc
+REAL_CFLAGS = -I./include $(shell pkg-config --cflags dri gbm libdrm glesv2 egl) -D_GNU_SOURCE -DBUILD_ELM327PLUGIN $(CFLAGS)
+REAL_LDFLAGS = $(shell pkg-config --libs dri gbm libdrm glesv2 egl) -lrt -lflutter_engine -lpthread -ldl $(LDFLAGS)
+
+SOURCES = src/flutter-pi.c src/platformchannel.c src/pluginregistry.c src/plugins/elm327plugin.c src/plugins/services-plugin.c src/plugins/testplugin.c
+OBJECTS = $(patsubst src/%.c,out/obj/%.o,$(SOURCES))
+
+all: out/flutter-pi
+
+out/obj/%.o: src/%.c
+	@mkdir -p $(@D)
+	$(CC) -c $(REAL_CFLAGS) $(REAL_LDFLAGS) $< -o $@
+
+out/flutter-pi: $(OBJECTS)
+	@mkdir -p $(@D)
+	$(CC) $(REAL_CFLAGS) $(REAL_LDFLAGS) $(OBJECTS) -o out/flutter-pi
+
+clean:
+	@mkdir -p out
+	rm -rf $(OBJECTS) out/flutter-pi out/obj/*

include/flutter-pi.h

@@ -9,8 +9,8 @@
 
 #define EGL_PLATFORM_GBM_KHR	0x31D7
 
-struct LinkedTaskListElement {
-    struct LinkedTaskListElement* next;
+struct FlutterPiTask {
+    struct FlutterPiTask* next;
 	bool is_vblank_event;
 	union {
 		FlutterTask task;

include/platformchannel.h

@@ -201,10 +201,10 @@ int PlatformChannel_encode(struct ChannelObject *object, uint8_t **buffer_out, s
 
 /// Encodes a generic ChannelObject (anything, string/binary codec or Standard/JSON Method Calls and responses) as a platform message
 /// and sends it to flutter on channel `channel`
-/// When flutter responds to this message, it is automatically decoded using the codec given in `response_codec`.
-/// Then, on_response is called with the decoded ChannelObject and the userdata as an argument.
-/// Flutter _should_ always respond to platform messages, so it's okay if not calling your handler would cause a memory leak
-///   (since that should never happen)
+/// If you supply a response callback (i.e. on_response is != NULL):
+///   when flutter responds to this message, it is automatically decoded using the codec given in `response_codec`.
+///   Then, on_response is called with the decoded ChannelObject and the userdata as an argument.
+///   It's possible that flutter won't respond to your platform message, like when sending events via an EventChannel.
 /// userdata can be NULL.
 int PlatformChannel_send(char *channel, struct ChannelObject *object, enum ChannelCodec response_codec, PlatformMessageResponseCallback on_response, void *userdata);
 

src/flutter-pi.c

@@ -15,6 +15,7 @@
 #include <limits.h>
 #include <float.h>
 #include <assert.h>
+#include <time.h>
 
 #include <xf86drm.h>
 #include <xf86drmMode.h>
@@ -118,32 +119,30 @@ struct {
 
 pthread_t io_thread_id;
 pthread_t platform_thread_id;
-struct LinkedTaskListElement task_list_head_sentinel = {
+struct FlutterPiTask tasklist = {
 	.next = NULL,
 	.is_vblank_event = false,
 	.target_time = 0,
 	.task = {.runner = NULL, .task = 0}
 };
-pthread_mutex_t task_list_lock;
-bool should_notify_platform_thread = false;
-sigset_t sigusr1_set;
-
+pthread_mutex_t tasklist_lock = PTHREAD_MUTEX_INITIALIZER;
+pthread_cond_t  task_added = PTHREAD_COND_INITIALIZER;
 
 
 /*********************
  * FLUTTER CALLBACKS *
  *********************/
 bool     		make_current(void* userdata) {
 	if (eglMakeCurrent(egl.display, egl.surface, egl.surface, egl.context) != EGL_TRUE) {
-		fprintf(stderr, "Could not make the context current.\n");
+		fprintf(stderr, "make_current: could not make the context current.\n");
 		return false;
 	}
 
 	return true;
 }
 bool     		clear_current(void* userdata) {
 	if (eglMakeCurrent(egl.display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT) != EGL_TRUE) {
-		fprintf(stderr, "Could not clear the current context.\n");
+		fprintf(stderr, "clear_current: could not clear the current context.\n");
 		return false;
 	}
 
@@ -165,10 +164,12 @@ struct drm_fb*	drm_fb_get_from_bo(struct gbm_bo *bo) {
 	uint32_t width, height, format, strides[4] = {0}, handles[4] = {0}, offsets[4] = {0}, flags = 0;
 	int ok = -1;
 
+	// if the buffer object already has some userdata associated with it,
+	//   it's the framebuffer we allocated.
 	struct drm_fb *fb = gbm_bo_get_user_data(bo);
-
 	if (fb) return fb;
 
+	// if there's no framebuffer for the bo, we need to create one.
 	fb = calloc(1, sizeof(struct drm_fb));
 	fb->bo = bo;
 
@@ -197,7 +198,7 @@ struct drm_fb*	drm_fb_get_from_bo(struct gbm_bo *bo) {
 
 	if (ok) {
 		if (flags)
-			fprintf(stderr, "Modifiers failed!\n");
+			fprintf(stderr, "drm_fb_get_from_bo: modifiers failed!\n");
 
 		memcpy(handles, (uint32_t [4]){gbm_bo_get_handle(bo).u32,0,0,0}, 16);
 		memcpy(strides, (uint32_t [4]){gbm_bo_get_stride(bo),0,0,0}, 16);
@@ -207,7 +208,7 @@ struct drm_fb*	drm_fb_get_from_bo(struct gbm_bo *bo) {
 	}
 
 	if (ok) {
-		fprintf(stderr, "failed to create fb: %s\n", strerror(errno));
+		fprintf(stderr, "drm_fb_get_from_bo: failed to create fb: %s\n", strerror(errno));
 		free(fb);
 		return NULL;
 	}
@@ -286,7 +287,7 @@ void 	 		cut_word_from_string(char* string, char* word) {
 		} while (word_in_str[i++ + word_length] != 0);
 	}
 }
-const GLubyte*	hacked_glGetString(GLenum name) {
+const GLubyte  *hacked_glGetString(GLenum name) {
 	if (name == GL_EXTENSIONS) {
 		static GLubyte* extensions;
 
@@ -365,7 +366,7 @@ const GLubyte*	hacked_glGetString(GLenum name) {
 		return glGetString(name);
 	}
 }
-void*    		proc_resolver(void* userdata, const char* name) {
+void           *proc_resolver(void* userdata, const char* name) {
 	if (name == NULL) return NULL;
 
 	/*  
@@ -405,58 +406,36 @@ void  handle_sigusr1(int _) {}
 bool  init_message_loop() {
 	platform_thread_id = pthread_self();
 
-	// first, initialize the task heap mutex
-	if (pthread_mutex_init(&task_list_lock, NULL) != 0) {
-		fprintf(stderr, "Could not initialize task list mutex\n");
-		return false;
-	}
-
-	sigemptyset(&sigusr1_set);
-	sigaddset(&sigusr1_set, SIGUSR1);
-	sigaction(SIGUSR1, &(struct sigaction) {.sa_handler = &handle_sigusr1}, NULL);
-	pthread_sigmask(SIG_UNBLOCK, &sigusr1_set, NULL);
-
 	return true;
 }
 bool  message_loop(void) {
-	should_notify_platform_thread =  true;
+	struct timespec abstargetspec;
+	uint64_t currenttime, abstarget;
 
 	while (true) {
-		pthread_mutex_lock(&task_list_lock);
-		if (task_list_head_sentinel.next == NULL) {
-			pthread_mutex_unlock(&task_list_lock);
-			sigwaitinfo(&sigusr1_set, NULL);
-			continue;
-		} else {
-			uint64_t target_time = task_list_head_sentinel.next->target_time;
-			uint64_t current_time = FlutterEngineGetCurrentTime();
-
-			if (target_time > current_time) {
-				uint64_t diff = target_time - current_time;
-
-				struct timespec target_timespec = {
-					.tv_sec = (uint64_t) (diff / 1000000000ull),
-					.tv_nsec = (uint64_t) (diff % 1000000000ull)
-				};
+		pthread_mutex_lock(&tasklist_lock);
 
-				pthread_mutex_unlock(&task_list_lock);
-				sigtimedwait(&sigusr1_set, NULL, &target_timespec);
-				continue;
-			}
+		// wait for a task to be inserted into the list
+		while ((tasklist.next == NULL))
+			pthread_cond_wait(&task_added, &tasklist_lock);
+		
+		// wait for a task to be ready to be run
+		while (tasklist.target_time > (currenttime = FlutterEngineGetCurrentTime())) {
+			clock_gettime(CLOCK_REALTIME, &abstargetspec);
+			abstarget = abstargetspec.tv_nsec + abstargetspec.tv_sec*1000000000ull - currenttime;
+			abstargetspec.tv_nsec = abstarget % 1000000000;
+			abstargetspec.tv_sec =  abstarget / 1000000000;
+			
+			pthread_cond_timedwait(&task_added, &tasklist_lock, &abstargetspec);
 		}
 
-		FlutterTask task = task_list_head_sentinel.next->task;
-		bool is_vblank_event = task_list_head_sentinel.next->is_vblank_event;
-		drmVBlankReply vbl = task_list_head_sentinel.next->vbl;
+		FlutterTask task = tasklist.next->task;
+		struct FlutterPiTask* new_first = tasklist.next->next;
+		free(tasklist.next);
+		tasklist.next = new_first;
 
-		struct LinkedTaskListElement* new_first = task_list_head_sentinel.next->next;
-		free(task_list_head_sentinel.next);
-		task_list_head_sentinel.next = new_first;
-		pthread_mutex_unlock(&task_list_lock);
-		
-		if (is_vblank_event) {
-			
-		} else if (FlutterEngineRunTask(engine, &task) != kSuccess) {
+		pthread_mutex_unlock(&tasklist_lock);
+		if (FlutterEngineRunTask(engine, &task) != kSuccess) {
 			fprintf(stderr, "Error running platform task\n");
 			return false;
 		};
@@ -465,24 +444,22 @@ bool  message_loop(void) {
 	return true;
 }
 void  post_platform_task(FlutterTask task, uint64_t target_time, void* userdata) {
-	struct LinkedTaskListElement* to_insert = malloc(sizeof(struct LinkedTaskListElement));
+	// prepare the task to be inserted into the tasklist.
+	struct FlutterPiTask* to_insert = malloc(sizeof(struct FlutterPiTask));
 	to_insert->next = NULL;
-	to_insert->is_vblank_event = false;
 	to_insert->task = task;
 	to_insert->target_time = target_time;
 
-	pthread_mutex_lock(&task_list_lock);
-	struct LinkedTaskListElement* this = &task_list_head_sentinel;
-	while ((this->next) != NULL && (target_time > this->next->target_time))
-		this = this->next;
-
-	to_insert->next = this->next;
-	this->next = to_insert;
-	pthread_mutex_unlock(&task_list_lock);
-
-	if (should_notify_platform_thread) {
-		pthread_kill(platform_thread_id, SIGUSR1);
-	}
+	// insert the task at a fitting position. (the tasks are ordered by target time)
+	pthread_mutex_lock(&tasklist_lock);
+		struct FlutterPiTask* this = &tasklist;
+		while ((this->next) != NULL && (target_time > this->next->target_time))
+			this = this->next;
+
+		to_insert->next = this->next;
+		this->next = to_insert;
+	pthread_mutex_unlock(&tasklist_lock);
+	pthread_cond_signal(&task_added);
 }
 bool  runs_platform_tasks_on_current_thread(void* userdata) {
 	return pthread_equal(pthread_self(), platform_thread_id) != 0;
@@ -572,7 +549,7 @@ bool init_display(void) {
 
 			// only update the physical size of the display if the values
 			//   are not yet initialized / not set with a commandline option
-			if (!((width_mm == 0) && (height_mm == 0))) {
+			if ((width_mm == 0) && (height_mm == 0)) {
 				if ((conn->mmWidth == 160) && (conn->mmHeight == 90)) {
 					// if width and height is exactly 160mm x 90mm, the values are probably bogus.
 					width_mm = 0;
@@ -939,6 +916,7 @@ bool init_application(void) {
 
 	return true;
 }
+
 void destroy_application(void) {
 	int ok;
 

src/platformchannel.c

@@ -204,7 +204,7 @@ int PlatformChannel_writeStdMsgCodecValueToBuffer(struct StdMsgCodecValue* value
 			break;
 		case kFloat64:
 			align8(pbuffer);
-			write64(pbuffer, (uint64_t) value->float64_value);
+			write64(pbuffer, *((uint64_t*) &(value->float64_value)));
 			advance(pbuffer, 8);
 			break;
 		case kLargeInt:
@@ -871,7 +871,6 @@ int PlatformChannel_encode(struct ChannelObject *object, uint8_t **buffer_out, s
 	*size_out = size;
 	return 0;
 
-
 	free_buffer_and_return_ok:
 	free(buffer);
 	return ok;
@@ -917,6 +916,13 @@ int PlatformChannel_send(char *channel, struct ChannelObject *object, enum Chann
 		if (result != kSuccess) return EINVAL;
 	}
 
+	//printf("[platformchannel] sending platform message to flutter on channel \"%s\". message_size: %d, has response_handle? %s\n", channel, size, response_handle ? "yes" : "no");
+	//printf("  message buffer: \"");
+	//for (int i = 0; i < size; i++)
+	//	if (isprint(buffer[i])) printf("%c", buffer[i]);
+	//	else printf("\\x%02X", buffer[i]);
+	//printf("\"\n");
+	
 	result = FlutterEngineSendPlatformMessage(
 		engine,
 		& (const FlutterPlatformMessage) {
@@ -960,8 +966,8 @@ int PlatformChannel_jsoncall(char *channel, char *method, struct JSONMsgCodecVal
 }
 int PlatformChannel_respond(FlutterPlatformMessageResponseHandle *handle, struct ChannelObject *response) {
 	FlutterEngineResult result;
-	uint8_t *buffer;
-	size_t   size;
+	uint8_t *buffer = NULL;
+	size_t   size = 0;
 	int ok;
 
 	ok = PlatformChannel_encode(response, &buffer, &size);

src/pluginregistry.c

@@ -26,12 +26,12 @@ struct {
 struct FlutterPiPlugin hardcoded_plugins[] = {
 	{.name = "services",     .init = Services_init, .deinit = Services_deinit},
 
-#ifdef INCLUDE_TESTPLUGIN	
+#ifdef BUILD_TESTPLUGIN	
 	{.name = "testplugin",   .init = TestPlugin_init, .deinit = TestPlugin_deinit}
 #endif
 
-#ifdef INCLUDE_ELM327PLUGIN
-	{.name = "elm327",       .init = ELM327Plugin_init, .deinit = ELM327Plugin_deinit}
+#ifdef BUILD_ELM327PLUGIN
+	{.name = "elm327plugin", .init = ELM327Plugin_init, .deinit = ELM327Plugin_deinit}
 #endif
 };
 //size_t hardcoded_plugins_count;