altosui: provide separate flush_input/flush_output for serial. deal with monitor automatically

(yes, this should be two patches, but the diffs in AltosSerial were merged together).

First, this replaces the existing flush/flush_reply mess with two simple functions,
one to flush output to the serial device, making sure that all data written will be seen
while we wait for input. The other sucks any pending input off of the serial line and
discards it.

Second, AltosSerial now tracks whether the serial line is being used for telemetry
monitoring. If so, it enables monitoring, otherwise it disables it. Eliminates a
bunch of manual state tracking elsewhere.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 40 insertions, 22 deletions

diff --git a/ao-tools/altosui/AltosSerial.java b/ao-tools/altosui/AltosSerial.java
index 5b47960f..99ba3324 100644
--- a/ao-tools/altosui/AltosSerial.java
+++ b/ao-tools/altosui/AltosSerial.java
@@ -47,6 +47,7 @@ public class AltosSerial implements Runnable {
 	String line;
 	byte[] line_bytes;
 	int line_count;
+	boolean monitor_mode;
 
 	public void run () {
 		int c;
@@ -99,35 +100,39 @@ public class AltosSerial implements Runnable {
 		}
 	}
 
-	public void flush_reply() {
+	public void flush_output() {
 		libaltos.altos_flush(altos);
+	}
+
+	public void flush_input() {
+		flush_output();
 		try {
-			Thread.sleep(100);
+			Thread.sleep(200);
 		} catch (InterruptedException ie) {
 		}
-		reply_queue.clear();
+		synchronized(this) {
+			if (!"VERSION".startsWith(line) &&
+			    !line.startsWith("VERSION"))
+				line = "";
+			reply_queue.clear();
+		}
 	}
 
 	public String get_reply() throws InterruptedException {
-		libaltos.altos_flush(altos);
+		flush_output();
 		String line = reply_queue.take();
 		return line;
 	}
 
 	public void add_monitor(LinkedBlockingQueue<String> q) {
+		set_monitor(true);
 		monitors.add(q);
 	}
 
 	public void remove_monitor(LinkedBlockingQueue<String> q) {
 		monitors.remove(q);
-	}
-
-	public void flush () {
-		synchronized(this) {
-			if (!"VERSION".startsWith(line) && !line.startsWith("VERSION"))
-				line = "";
-			reply_queue.clear();
-		}
+		if (monitors.isEmpty())
+			set_monitor(false);
 	}
 
 	public boolean opened() {
@@ -135,8 +140,9 @@ public class AltosSerial implements Runnable {
 	}
 
 	public void close() {
-		if (altos != null)
+		if (altos != null) {
 			libaltos.altos_close(altos);
+		}
 		if (input_thread != null) {
 			try {
 				input_thread.interrupt();
@@ -157,7 +163,7 @@ public class AltosSerial implements Runnable {
 	}
 
 	public void print(String data) {
-//h		System.out.printf("\"%s\" ", data);
+//		System.out.printf("\"%s\" ", data);
 		for (int i = 0; i < data.length(); i++)
 			putc(data.charAt(i));
 	}
@@ -173,17 +179,28 @@ public class AltosSerial implements Runnable {
 			throw new FileNotFoundException(device.getPath());
 		input_thread = new Thread(this);
 		input_thread.start();
-		print("\nE 0\n");
-		try {
-			Thread.sleep(200);
-		} catch (InterruptedException e) {
-		}
-		flush();
+		print("~\nE 0\n");
+		set_monitor(monitor_mode);
+		flush_input();
 	}
 
 	public void set_channel(int channel) {
-		if (altos != null)
-			printf("m 0\nc r %d\nm 1\n", channel);
+		if (altos != null) {
+			if (monitor_mode)
+				printf("m 0\nc r %d\nm 1\n", channel);
+			else
+				printf("c r %d\n", channel);
+		}
+	}
+
+	void set_monitor(boolean monitor) {
+		monitor_mode = monitor;
+		if (altos != null) {
+			if (monitor)
+				printf("m 1\n");
+			else
+				printf("m 0\n");
+		}
 	}
 
 	public void set_callsign(String callsign) {
@@ -195,6 +212,7 @@ public class AltosSerial implements Runnable {
 		altos = null;
 		input_thread = null;
 		line = "";
+		monitor_mode = false;
 		monitors = new LinkedList<LinkedBlockingQueue<String>> ();
 		reply_queue = new LinkedBlockingQueue<String> ();
 	}