Implement dequeue function and send then in serial line. #1 #2

Shortcomings: This seems to block on long blocks and transactions and
it sends string "empty" on wire even if there is nothing to
send. Also, no synchronization or block compaction is performed.

src/bitcoin.c

@@ -131,6 +131,17 @@ bool bitcoin_inv_insert(struct bitcoin_storage const *st, struct msg *const m)
 	return true;
 }
 
+const struct msg *bitcoin_dequeue(struct bitcoin_storage const *st)
+{
+	// Fetch and dequeue key
+	GSequenceIter *it = g_sequence_get_begin_iter(st->send_queue);
+	guchar *key = g_sequence_get(it);
+	g_sequence_remove(it);
+
+	// Fetch value (or NULL in case of failure)
+	return g_hash_table_lookup(st->inv,key);
+}
+
 /**
  * Calculates a hash for use internally in Hash Table storage. This
  * hash should not be used outside g_hash_table.

src/bitcoin.h

@@ -129,6 +129,11 @@ struct bitcoin_storage bitcoin_new_storage();
  */
 bool bitcoin_inv_insert(struct bitcoin_storage const *st, struct msg *const m);
 
+/**
+ * Fetches unsent message with highest sending priority.
+ */
+const struct msg *bitcoin_dequeue(struct bitcoin_storage const *st);
+
 /**
  * Returns message type of given wire message.
  */

src/main.c

@@ -14,7 +14,7 @@
 #include "bitcoin.h"
 
 // Prototypes
-void serial(const int fd);
+void serial(const int devfd, struct bitcoin_storage *const st);
 
 int main(int argc, char *argv[])
 {
@@ -73,21 +73,31 @@ int main(int argc, char *argv[])
 		if (ret < 1) err(5,"Error while polling");
 
 		// Always serve slow serial first
-		if (fds[0].revents & POLLOUT) serial(dev_fd);
+		if (fds[0].revents & POLLOUT) serial(dev_fd,&st);
 		if (fds[1].revents & POLLIN) incoming_node_data(node_fd,&st);
 	}
 }
 
-void serial(const int devfd) {
-	// Just dummy writer for generating much traffic to serial
-	static guint8 i=0;
-	char instanssi[43];
-	snprintf(instanssi,sizeof(instanssi),
-		 "Kissa kissa kissa kissa... Instanssi! %3hhu\n",
-		 i++);
-
-	// Write the output. Do not care if some output is ignored.
-	const int ret = write(devfd,instanssi,sizeof(instanssi)-1);
-	if (ret < 1) err(4,"Unable to write to serial port");
-	printf("sent %d bytes to serial port\n",ret);
+void serial(const int devfd, struct bitcoin_storage *const st)
+{
+	gint size = g_sequence_get_length(st->send_queue);
+
+	if (size==0) {
+		const char buf[] = "empty ";
+		const int ret = write(devfd,buf,sizeof(buf)-1);
+		if (ret < 1) err(4,"Unable to write to serial port");
+	} else {
+		const struct msg *m = bitcoin_dequeue(st);
+
+		printf("Sending %s %s, queue size is %d\n",
+		       bitcoin_type_str(m),
+		       hex256(bitcoin_inv_hash(m)),
+		       size);
+
+		// FIXME no two writes inside single call!
+		const int ret1 = write(devfd,&m->type,1); // FIXME byte ordering issue
+		if (ret1 < 1) err(4,"Unable to write to serial port");
+		const int ret2 = write(devfd,m->payload,m->length);
+		if (ret2 < 1) err(4,"Unable to write to serial port");
+	}
 }