Implement loopback backend

1 files changed, 120 insertions, 0 deletions

diff --git a/loopback.c b/loopback.c
new file mode 100644
index 0000000..56e8759
--- /dev/null
+++ b/loopback.c
@@ -0,0 +1,120 @@
+#include <string.h>
+#include "loopback.h"
+
+#define BACKEND_NAME "loopback"
+
+int init(){
+	backend loopback = {
+		.name = BACKEND_NAME,
+		.conf = backend_configure,
+		.create = backend_instance,
+		.conf_instance = backend_configure_instance,
+		.channel = backend_channel,
+		.handle = backend_set,
+		.process = backend_handle,
+		.start = backend_start,
+		.shutdown = backend_shutdown
+	};
+
+	//register backend
+	if(mm_backend_register(loopback)){
+		fprintf(stderr, "Failed to register loopback backend\n");
+		return 1;
+	}
+	return 0;
+}
+
+static int backend_configure(char* option, char* value){
+	//intentionally ignored
+	return 0;
+}
+
+static int backend_configure_instance(instance* instance, char* option, char* value){
+	//intentionally ignored
+	return 0;
+}
+
+static instance* backend_instance(){
+	instance* i = mm_instance();
+	if(!i){
+		return NULL;
+	}
+
+	i->impl = calloc(1, sizeof(loopback_instance));
+	if(!i->impl){
+		fprintf(stderr, "Failed to allocate memory\n");
+		return NULL;
+	}
+
+	return i;
+}
+
+static channel* backend_channel(instance* inst, char* spec){
+	size_t u;
+	loopback_instance* data = (loopback_instance*) inst->impl;
+
+	//find matching channel
+	for(u = 0; u < data->n; u++){
+		if(!strcmp(spec, data->name[u])){
+			break;
+		}
+	}
+
+	//allocate new channel
+	if(u == data->n){
+		data->name = realloc(data->name, (u + 1) * sizeof(char*));
+		if(!data->name){
+			fprintf(stderr, "Failed to allocate memory\n");
+			return NULL;
+		}
+
+		data->name[u] = strdup(spec);
+		if(!data->name[u]){
+			fprintf(stderr, "Failed to allocate memory\n");
+			return NULL;
+		}
+		data->n++;
+	}
+
+	return mm_channel(inst, u, 1);
+}
+
+static int backend_set(instance* inst, size_t num, channel** c, channel_value* v){
+	size_t n;
+	for(n = 0; n < num; n++){
+		mm_channel_event(c[n], v[n]);
+	}
+	return 0;
+}
+
+static int backend_handle(size_t num, managed_fd* fds){
+	//no events generated here
+	return 0;
+}
+
+static int backend_start(){
+	return 0;
+}
+
+static int backend_shutdown(){
+	size_t n, u, p;
+	instance** inst = NULL;
+	loopback_instance* data = NULL;
+
+	if(mm_backend_instances(BACKEND_NAME, &n, &inst)){
+		fprintf(stderr, "Failed to fetch instance list\n");
+		return 1;
+	}
+
+	for(u = 0; u < n; u++){
+		data = (loopback_instance*) inst[u]->impl;
+		for(p = 0; p < data->n; p++){
+			free(data->name[p]);
+		}
+		free(data->name);
+		free(inst[u]->impl);
+	}
+
+	free(inst);
+	return 0;
+}