Rework the up connection state machine.

It is now more similar to the down connection, using the onclose
callback for resource management.

README.FRONTEND

@@ -40,11 +40,10 @@ serverConnection.ondownstream = ...;
 ```
 
 The `onconnected` callback is called when we connect to the server.  The
-`onclose` callback is called when the socket is closed; you should use it
-to close all your up streams (down streams will be closed by the server).
-The `onusermessage` callback indicates an application-specific message,
-either from another user or from the server; the field `kind` indicates
-the kind of message.
+`onclose` callback is called when the socket is closed; all streams will
+have been closed by the time it is called.  The `onusermessage` callback
+indicates an application-specific message, either from another user or
+from the server; the field `kind` indicates the kind of message.
 
 Once you have joined a group (see below), the remaining callbacks may
 trigger.  The `onuser` callback is used to indicate that a user has joined
@@ -126,8 +125,8 @@ a change in the status of the stream; states `connected` and `complete`
 indicate a functioning stream; other states indicate that the stream is
 not working right now but might recover in the future.
 
-The `onclose` callback is called when the stream is destroyed by the
-server.
+The `onclose` callback is called when the stream is destroyed, either by
+the server or in response to a call to the `close` method.
 
 ## Pushing outgoing video streams
 

static/galene.js

@@ -309,7 +309,6 @@ function gotConnected() {
  * @param {string} reason
  */
 function gotClose(code, reason) {
-    delUpMediaKind(null);
     setConnected(false);
     if(code != 1000) {
         console.warn('Socket close', code, reason);
@@ -374,7 +373,7 @@ getButtonElement('presentbutton').onclick = async function(e) {
 
 getButtonElement('unpresentbutton').onclick = function(e) {
     e.preventDefault();
-    delUpMediaKind('local');
+    closeUpMediaKind('local');
     resizePeers();
 };
 
@@ -482,13 +481,13 @@ document.getElementById('sharebutton').onclick = function(e) {
 
 document.getElementById('unsharebutton').onclick = function(e) {
     e.preventDefault();
-    delUpMediaKind('screenshare');
+    closeUpMediaKind('screenshare');
     resizePeers();
 };
 
 document.getElementById('stopvideobutton').onclick = function(e) {
     e.preventDefault();
-    delUpMediaKind('video');
+    closeUpMediaKind('video');
     resizePeers();
 };
 
@@ -757,10 +756,6 @@ function newUpStream(id) {
     c.onerror = function(e) {
         console.error(e);
         displayError(e);
-        delUpMedia(c);
-    };
-    c.onabort = function() {
-        delUpMedia(c);
     };
     c.onnegotiationcompleted = function() {
         setMaxVideoThroughput(c, getMaxVideoThroughput());
@@ -928,23 +923,16 @@ function setFilter(c, f) {
             c.userdata.filter.stop();
             c.userdata.filter = null;
         }
-        if(!c.onclose) {
-            console.warn("onclose not set, this shouldn't happen");
-            c.onclose = null;
-        }
         return
     }
 
     if(c.userdata.filter)
         setFilter(c, null);
 
-    if(c.onclose)
-        throw new Error('onclose already taken');
     if(f.inputStream != c.stream)
         throw new Error('Setting filter for wrong stream');
     c.stream = f.outputStream;
     c.userdata.filter = f;
-    c.onclose = () => setFilter(c, null);
 }
 
 /**
@@ -1028,13 +1016,10 @@ async function addLocalMedia(id) {
 
     if(!audio && !video) {
         if(old)
-            delUpMedia(old);
+            old.close();
         return;
     }
 
-    if(old)
-        stopUpMedia(old);
-
     let constraints = {audio: audio, video: video};
     /** @type {MediaStream} */
     let stream = null;
@@ -1043,7 +1028,7 @@ async function addLocalMedia(id) {
     } catch(e) {
         displayError(e);
         if(old)
-            delUpMedia(old);
+            old.close();
         return;
     }
 
@@ -1058,8 +1043,22 @@ async function addLocalMedia(id) {
         try {
             let f = new Filter(stream, filter);
             setFilter(c, f);
+            c.onclose = () => {
+                stopStream(stream);
+                setFilter(c, null);
+                delMedia(c.id);
+            }
         } catch(e) {
             displayWarning(e);
+            c.onclose = () => {
+                stopStream(c.stream);
+                delMedia(c.id);
+            }
+        }
+    } else {
+        c.onclose = () => {
+            stopStream(c.stream);
+            delMedia(c.id);
         }
     }
 
@@ -1110,11 +1109,13 @@ async function addShareMedia() {
     let c = newUpStream();
     c.kind = 'screenshare';
     c.stream = stream;
+    c.onclose = () => {
+        stopStream(stream);
+        delMedia(c.id);
+    }
     stream.getTracks().forEach(t => {
         c.pc.addTrack(t, stream);
-        t.onended = e => {
-            delUpMedia(c);
-        };
+        t.onended = e => c.close();
         c.labels[t.id] = 'screenshare';
     });
     c.onstats = gotUpStats;
@@ -1144,12 +1145,14 @@ async function addFileMedia(file) {
     c.kind = 'video';
     c.stream = stream;
     c.onclose = function() {
+        stopStream(c.stream);
         let media = /** @type{HTMLVideoElement} */
             (document.getElementById('media-' + this.id));
         if(media && media.src) {
             URL.revokeObjectURL(media.src);
             media.src = null;
         }
+        delMedia(c.id);
     }
 
     stream.onaddtrack = function(e) {
@@ -1186,7 +1189,7 @@ async function addFileMedia(file) {
         if(Object.keys(c.labels).length === 0) {
             stream.onaddtrack = null;
             stream.onremovetrack = null;
-            delUpMedia(c);
+            c.close();
         }
     };
     await setMedia(c, true, false, video);
@@ -1195,13 +1198,10 @@ async function addFileMedia(file) {
 }
 
 /**
- * @param {Stream} c
+ * @param {MediaStream} s
  */
-function stopUpMedia(c) {
-    setFilter(c, null);
-    if(!c.stream)
-        return;
-    c.stream.getTracks().forEach(t => {
+function stopStream(s) {
+    s.getTracks().forEach(t => {
         try {
             t.stop();
         } catch(e) {
@@ -1211,31 +1211,18 @@ function stopUpMedia(c) {
 }
 
 /**
- * @param {Stream} c
- */
-function delUpMedia(c) {
-    stopUpMedia(c);
-    c.close();
-    delMedia(c.id);
-    delete(serverConnection.up[c.id]);
-    setButtonsVisibility();
-}
-
-/**
- * delUpMediaKind reoves all up media of the given kind.  If kind is
- * falseish, it removes all up media.
+ * closeUpMediaKind closes all up connections that correspond to a given
+ * kind of media.  If kind is null, it closes all up connections.
+ *
  * @param {string} kind
 */
-function delUpMediaKind(kind) {
+function closeUpMediaKind(kind) {
     for(let id in serverConnection.up) {
         let c = serverConnection.up[id];
         if(kind && c.kind != kind)
             continue
-        delUpMedia(c);
+        c.close();
     }
-
-    setButtonsVisibility();
-    hideVideo();
 }
 
 /**
@@ -1501,6 +1488,7 @@ function delMedia(id) {
     media.srcObject = null;
     mediadiv.removeChild(peer);
 
+    setButtonsVisibility();
     resizePeers();
     hideVideo();
 }

static/protocol.js

@@ -238,12 +238,10 @@ ServerConnection.prototype.connect = async function(url) {
             sc.permissions = {};
             for(let id in sc.up) {
                 let c = sc.up[id];
-                delete(sc.up[id]);
                 c.close();
             }
             for(let id in sc.down) {
                 let c = sc.down[id];
-                delete(sc.down[id]);
                 c.close();
             }
             if(sc.group && sc.onjoined)
@@ -408,9 +406,9 @@ ServerConnection.prototype.newUpStream = function(id) {
     let pc = new RTCPeerConnection(sc.rtcConfiguration);
     if(!pc)
         throw new Error("Couldn't create peer connection");
-    if(sc.up[id]) {
+    if(sc.up[id])
         sc.up[id].close();
-    }
+
     let c = new Stream(this, id, pc, true);
     sc.up[id] = c;
 
@@ -530,7 +528,6 @@ ServerConnection.prototype.gotOffer = async function(id, labels, source, usernam
         // SDP is rather inflexible as to what can be renegotiated.
         // Unless the server indicates that this is a renegotiation with
         // all parameters unchanged, tear down the existing connection.
-        delete(sc.down[id]);
         c.close(true);
         c = null;
     }
@@ -669,7 +666,6 @@ ServerConnection.prototype.gotClose = function(id) {
     let c = this.down[id];
     if(!c)
         throw new Error('unknown down stream');
-    delete(this.down[id]);
     c.close();
 };
 
@@ -888,19 +884,17 @@ function Stream(sc, id, pc, up) {
  */
 Stream.prototype.close = function(nocallback) {
     let c = this;
+
+    if(!c.sc) {
+        console.warn('Closing closed stream');
+        return;
+    }
+
     if(c.statsHandler) {
         clearInterval(c.statsHandler);
         c.statsHandler = null;
     }
 
-    if(c.stream) {
-        c.stream.getTracks().forEach(t => {
-            try {
-                t.stop();
-            } catch(e) {
-            }
-        });
-    }
     c.pc.close();
 
     if(c.up && c.localDescriptionSent) {
@@ -913,9 +907,21 @@ Stream.prototype.close = function(nocallback) {
         }
     }
 
+    if(c.up) {
+        if(c.sc.up[c.id] === c)
+            delete(c.sc.up[c.id]);
+        else
+            console.warn('Closing unknown stream');
+    } else {
+        if(c.sc.down[c.id] === c)
+            delete(c.sc.down[c.id]);
+        else
+            console.warn('Closing unknown stream');
+    }
+    c.sc = null;
+
     if(!nocallback && c.onclose)
         c.onclose.call(c);
-    c.sc = null;
 };
 
 /**