[icedtea-web] RFC: Patch to stabilize applet initialization
Deepak Bhole
dbhole at redhat.com
Fri Oct 22 08:27:45 PDT 2010
* Dr Andrew John Hughes <ahughes at redhat.com> [2010-10-21 17:52]:
> On 17:38 Thu 21 Oct , Deepak Bhole wrote:
> > Hi,
> >
> > The attached patch envelopes fixes for two of Andrew's pending patches
> > (fixing 100% CPU load and the frame pop-up issue). In addition to those,
> > it fixes a lot of other initialization issues, particularly when
> > initializing multiple applets and/or closing other tabs with applets
> > which are being initialized.
> >
> > With this patch, I tested over 200 parallel applet inits, randomly
> > closing tabs, and everything works correctly.
> >
> > One known issue is that if timed correctly, a frame can appear outside
> > for a fraction of a second. It always goes away instantly though, and I
> > will be posting a patch to fix that problem in the near future.
> >
> > Cheers,
> > Deepak
>
> Do you have a ChangeLog for this? It would be good to know why each change
> is being made.
>
> In particular, why:
>
> > +
> > + // Add first, remove later
> > + newFrame.add("Center", panel);
> > oldFrame.remove(panel);
> > oldFrame.dispose();
> > + } else {
> > + newFrame.add("Center", panel);
> > }
> >
> > - newFrame.add("Center", panel);
>
> is this necessary?
>
As crazy as that looks, yes. here is the full piece of the code:
PluginAppletViewer newFrame = new PluginAppletViewer(handle, identifier, statusMsgStream, panel);
if (oldFrame != null) {
applets.remove(oldFrame.identifier);
oldFrame.removeWindowListener(oldFrame.windowEventListener);
panel.removeAppletListener(oldFrame.appletEventListener);
// Add first, remove later
newFrame.add("Center", panel);
oldFrame.remove(panel);
oldFrame.dispose();
} else {
newFrame.add("Center", panel);
}
oldFrame is an embedded frame in which an applet instance resides, newFrame is
another embedded frame with a different handle that it needs to be moved to. In
addition to being implanted in oldFrame, oldFrame is also registered as a
listener for a few things. We first need to unregister those listeners. We then
need to add it to the newFrame right away, as there are problems if the panel
does not have a parent. Hence the add being done in the if loop.
There is a second case where there may be no previous parent frame at all
(initial embedding) -- in this case, we need to do the add() in the else
otherwise it will get added twice.
The change I alluded to in the original email (to fix the pop-out frame
completely) will get rid of the above if/else condition btw, so it is only
temporary.
Cheers,
Deepak
> Also there seems to be some odd whitespace changes and excessive (8 space) indenting.
>
> > diff -r 85db7b3a1c93 plugin/icedteanp/java/sun/applet/PluginAppletViewer.java
> > --- a/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java Thu Oct 21 21:12:21 2010 +0100
> > +++ b/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java Thu Oct 21 17:22:56 2010 -0700
> > @@ -136,12 +136,10 @@
> > }
> > }
> > });
> > +
> > + // create the frame.
> > + PluginAppletViewer.reFrame(null, identifier, System.out, 0, panel);
> >
> > -
> > -
> > - // create the frame.
> > - PluginAppletViewer.reFrame(null, identifier, System.out, handle, panel);
> > -
> > panel.init();
> >
> > // Start the applet
> > @@ -179,15 +177,7 @@
> >
> > // Wait for the panel to initialize
> > // (happens in a separate thread)
> > - while (panel.getApplet() == null &&
> > - ((NetxPanel) panel).isAlive()) {
> > - try {
> > - Thread.sleep(50);
> > - PluginDebug.debug("Waiting for applet to initialize...");
> > - } catch (InterruptedException ie) {
> > - // just wait
> > - }
> > - }
> > + PluginAppletViewer.waitForAppletInit((NetxPanel) panel);
> >
> > a = panel.getApplet();
> >
> > @@ -317,7 +307,17 @@
> > */
> > private static String defaultSaveFile = "Applet.ser";
> >
> > - private static enum PAV_INIT_STATUS {PRE_INIT, IN_INIT, INIT_COMPLETE, INACTIVE};
> > +
> > + /**
> > + * Enumerates the current status of an applet
> > + *
> > + * PRE_INIT -> Parsing and initialization phase
> > + * INIT_COMPLETE -> Initialization complete, reframe pending
> > + * REFRAME_COMPLETE -> Reframe complete, applet is initialized and usable by the user
> > + * INACTIVE -> Browser has directed that the applet be destroyed (this state is non-overridable except by DESTROYED)
> > + * DESTROYED -> Applet has been destroyed
> > + */
> > + private static enum PAV_INIT_STATUS {PRE_INIT, INIT_COMPLETE, REFRAME_COMPLETE, INACTIVE, DESTROYED};
> >
> > /**
> > * The panel in which the applet is being displayed.
> > @@ -350,7 +350,6 @@
> >
> > private static HashMap<Integer, PAV_INIT_STATUS> status =
> > new HashMap<Integer,PAV_INIT_STATUS>();
> > -
> >
> > private long handle = 0;
> > private WindowListener windowEventListener = null;
> > @@ -380,16 +379,20 @@
> > return;
> >
> > PluginAppletViewer newFrame = new PluginAppletViewer(handle, identifier, statusMsgStream, panel);
> > -
> > +
> > if (oldFrame != null) {
> > applets.remove(oldFrame.identifier);
> > oldFrame.removeWindowListener(oldFrame.windowEventListener);
> > panel.removeAppletListener(oldFrame.appletEventListener);
> > +
> > + // Add first, remove later
> > + newFrame.add("Center", panel);
> > oldFrame.remove(panel);
> > oldFrame.dispose();
> > + } else {
> > + newFrame.add("Center", panel);
> > }
> >
> > - newFrame.add("Center", panel);
> > newFrame.pack();
> >
> > newFrame.appletEventListener = new AppletEventListener(newFrame, newFrame);
> > @@ -397,11 +400,6 @@
> >
> > applets.put(identifier, newFrame);
> >
> > - // dispose oldframe if necessary
> > - if (oldFrame != null) {
> > - oldFrame.dispose();
> > - }
> > -
> > PluginDebug.debug(panel + " reframed");
> > }
> >
> > @@ -449,7 +447,7 @@
> > this.frame = frame;
> > this.appletViewer = appletViewer;
> > }
> > -
> > +
> > public void appletStateChanged(AppletEvent evt)
> > {
> > AppletPanel src = (AppletPanel)evt.getSource();
> > @@ -483,9 +481,9 @@
> > AppletPanel.changeFrameAppContext(frame, SunToolkit.targetToAppContext(a));
> > else
> > AppletPanel.changeFrameAppContext(frame, AppContext.getAppContext());
> > -
> > - status.put(appletViewer.identifier, PAV_INIT_STATUS.INIT_COMPLETE);
> > -
> > +
> > + updateStatus(appletViewer.identifier, PAV_INIT_STATUS.INIT_COMPLETE);
> > +
> > break;
> > }
> > }
> > @@ -510,7 +508,13 @@
> >
> > try {
> > if (message.startsWith("handle")) {
> > -
> > +
> > + // If there is a key for this status, it means it
> > + // was either initialized before, or destroy has been
> > + // processed. Stop moving further.
> > + if (updateStatus(identifier, PAV_INIT_STATUS.PRE_INIT) != null)
> > + return;
> > +
> > // Extract the information from the message
> > String[] msgParts = new String[4];
> > for (int i=0; i < 3; i++) {
> > @@ -519,32 +523,38 @@
> > msgParts[i] = message.substring(spaceLocation + 1, nextSpaceLocation);
> > message = message.substring(nextSpaceLocation + 1);
> > }
> > -
> > +
> > long handle = Long.parseLong(msgParts[0]);
> > String width = msgParts[1];
> > String height = msgParts[2];
> > -
> > +
> > int spaceLocation = message.indexOf(' ', "tag".length()+1);
> > String documentBase =
> > UrlUtil.decode(message.substring("tag".length() + 1, spaceLocation));
> > - String tag = message.substring(spaceLocation+1);
> > + String tag = message.substring(spaceLocation+1);
> > +
> > + // Decode the tag
> > + tag = tag.replace(">", ">");
> > + tag = tag.replace("<", "<");
> > + tag = tag.replace("&", "&");
> > + tag = tag.replace(" ", "\n");
> > + tag = tag.replace(" ", "\r");
> > + tag = tag.replace(""", "\"");
> >
> > PluginDebug.debug ("Handle = " + handle + "\n" +
> > "Width = " + width + "\n" +
> > "Height = " + height + "\n" +
> > "DocumentBase = " + documentBase + "\n" +
> > "Tag = " + tag);
> > -
> > - status.put(identifier, PAV_INIT_STATUS.PRE_INIT);
> > +
> > PluginAppletViewer.parse
> > (identifier, handle, width, height,
> > new StringReader(tag),
> > new URL(documentBase));
> > -
> >
> > int maxWait = APPLET_TIMEOUT; // wait for applet to fully load
> > int wait = 0;
> > - while (!status.get(identifier).equals(PAV_INIT_STATUS.INIT_COMPLETE) &&
> > + while ( !applets.containsKey(identifier) && // Map is populated only by reFrame
> > (wait < maxWait)) {
> >
> > try {
> > @@ -555,9 +565,44 @@
> > }
> > }
> >
> > - if (!status.get(identifier).equals(PAV_INIT_STATUS.INIT_COMPLETE))
> > + // If wait exceeded maxWait, we timed out. Throw an exception
> > + if (wait >= maxWait)
> > throw new Exception("Applet initialization timeout");
> >
> > + PluginAppletViewer oldFrame = applets.get(identifier);
> > +
> > + // We should not try to destroy an applet during
> > + // initialization. It may cause an inconsistent state,
> > + // which would bad if it's a trusted applet that
> > + // read/writes to files
> > + waitForAppletInit((NetxPanel) applets.get(identifier).panel);
> > +
> > + // Should we proceed with reframing?
> > + if (status.get(identifier).equals(PAV_INIT_STATUS.INACTIVE)) {
> > + destroyApplet(identifier);
> > + return;
> > + }
> > +
> > + // Proceed with re-framing
> > + reFrame(oldFrame, identifier, System.out, handle, oldFrame.panel);
> > +
> > + // There is a slight chance that destroy can happen
> > + // between the above and below line
> > + if (updateStatus(identifier, PAV_INIT_STATUS.REFRAME_COMPLETE).equals(PAV_INIT_STATUS.INACTIVE)) {
> > + destroyApplet(identifier);
> > + }
> > +
> > + } else if (message.startsWith("destroy")) {
> > +
> > + // Set it inactive, and try to do cleanup is applicable
> > + PAV_INIT_STATUS previousStatus = updateStatus(identifier, PAV_INIT_STATUS.INACTIVE);
> > + PluginDebug.debug("Destroy status set for " + identifier);
> > +
> > + if (previousStatus != null &&
> > + previousStatus.equals(PAV_INIT_STATUS.REFRAME_COMPLETE)) {
> > + destroyApplet(identifier);
> > + }
> > +
> > } else {
> > PluginDebug.debug ("Handling message: " + message + " instance " + identifier + " " + Thread.currentThread());
> >
> > @@ -568,7 +613,7 @@
> > status.get(identifier).equals(PAV_INIT_STATUS.PRE_INIT)
> > )
> > );
> > -
> > +
> > // don't bother processing further for inactive applets
> > if (status.get(identifier).equals(PAV_INIT_STATUS.INACTIVE))
> > return;
> > @@ -580,31 +625,131 @@
> > e.printStackTrace();
> >
> > // If an exception happened during pre-init, we need to update status
> > - if (status.get(identifier).equals(PAV_INIT_STATUS.PRE_INIT))
> > - status.put(identifier, PAV_INIT_STATUS.INACTIVE);
> > + updateStatus(identifier, PAV_INIT_STATUS.INACTIVE);
> >
> > throw new RuntimeException("Failed to handle message: " +
> > message + " for instance " + identifier, e);
> > }
> > }
> > -
> > +
> > + /**
> > + * Sets the status unless an overriding status is set (e.g. if
> > + * status is DESTROYED, it may not be overridden).
> > + *
> > + * @param identifier The identifier for which the status is to be set
> > + * @param status The status to switch to
> > + * @return The previous status
> > + */
> > + private static synchronized PAV_INIT_STATUS updateStatus(int identifier, PAV_INIT_STATUS newStatus) {
> > +
> > + PAV_INIT_STATUS prev = status.get(identifier);
> > +
> > + // If the status is set
> > + if (status.containsKey(identifier)) {
> > +
> > + // Nothing may override destroyed status
> > + if (status.get(identifier).equals(PAV_INIT_STATUS.DESTROYED)) {
> > + return prev;
> > + }
> > +
> > + // If status is inactive, only DESTROYED may override it
> > + if (status.get(identifier).equals(PAV_INIT_STATUS.INACTIVE)) {
> > + if (!newStatus.equals(PAV_INIT_STATUS.DESTROYED)) {
> > + return prev;
> > + }
> > + }
> > + }
> > +
> > + // Else set to given status
> > + status.put(identifier, newStatus);
> > +
> > + return prev;
> > + }
> > +
> > + /**
> > + * Destroys the given applet instance.
> > + *
> > + * This function may be called multiple times without problems.
> > + * It does a synchronized check on the status and will only
> > + * attempt to destroy the applet if not previously destroyed.
> > + *
> > + * @param identifier The instance which is to be destroyed
> > + */
> > +
> > + private static synchronized void destroyApplet(int identifier) {
> > +
> > + PluginDebug.debug("DestroyApplet called for " + identifier);
> > +
> > + PAV_INIT_STATUS prev = updateStatus(identifier, PAV_INIT_STATUS.DESTROYED);
> > +
> > + // If already destroyed, return
> > + if (prev.equals(PAV_INIT_STATUS.DESTROYED)) {
> > + PluginDebug.debug(identifier + " already destroyed. Returning.");
> > + return;
> > + }
> > +
> > + // If already disposed, return
> > + if (applets.get(identifier).panel.applet == null) {
> > + // Try to still dispose the panel itself -- no harm done with double dispose
> > + applets.get(identifier).dispose();
> > +
> > + PluginDebug.debug(identifier + " inactive. Returning.");
> > + return;
> > + }
> > +
> > + PluginDebug.debug("Attempting to destroy " + identifier);
> > +
> > + final int fIdentifier = identifier;
> > + SwingUtilities.invokeLater(new Runnable() {
> > + public void run() {
> > + applets.get(fIdentifier).appletClose();
> > + }
> > + });
> > +
> > + PluginDebug.debug(identifier + " destroyed");
> > + }
> > +
> > + /**
> > + * Function to block until applet initialization is complete
> > + *
> > + * @param identifier The instance to wait for
> > + */
> > + public static void waitForAppletInit(NetxPanel panel) {
> > +
> > + int waitTime = 0;
> > +
> > + // Wait till initialization finishes
> > + while (panel.getApplet() == null &&
> > + panel.isAlive() &&
> > + waitTime < APPLET_TIMEOUT) {
> > + try {
> > + if (waitTime%500 == 0)
> > + PluginDebug.debug("Waiting for applet panel " + panel + " to initialize...");
> > +
> > + Thread.sleep(waitTime += 50);
> > + } catch (InterruptedException ie) {
> > + // just wait
> > + }
> > + }
> > +
> > + PluginDebug.debug("Applet panel " + panel + " initialized");
> > + }
> > +
> > public void handleMessage(int reference, String message)
> > {
> > if (message.startsWith("width")) {
> >
> > // Wait for panel to come alive
> > int maxWait = APPLET_TIMEOUT; // wait for panel to come alive
> > - int wait = 0;
> > + int wait = 0;
> > while (!status.get(identifier).equals(PAV_INIT_STATUS.INIT_COMPLETE) && wait < maxWait) {
> > -
> > - try {
> > - Thread.sleep(50);
> > - wait += 50;
> > - } catch (InterruptedException ie) {
> > - // just wait
> > - }
> > - }
> > -
> > + try {
> > + Thread.sleep(50);
> > + wait += 50;
> > + } catch (InterruptedException ie) {
> > + // just wait
> > + }
> > + }
> >
> > // 0 => width, 1=> width_value, 2 => height, 3=> height_value
> > String[] dimMsg = message.split(" ");
> > @@ -636,7 +781,7 @@
> >
> > panel.setSize(width, height);
> > panel.validate();
> > -
> > +
> > panel.applet.resize(width, height);
> > panel.applet.validate();
> > }
> > @@ -649,9 +794,6 @@
> > e.printStackTrace();
> > }
> >
> > - } else if (message.startsWith("destroy")) {
> > - dispose();
> > - status.put(identifier, PAV_INIT_STATUS.INACTIVE);
> > } else if (message.startsWith("GetJavaObject")) {
> >
> > // FIXME: how do we determine what security context this
> > @@ -672,15 +814,7 @@
> >
> > // Wait for the panel to initialize
> > // (happens in a separate thread)
> > - while (panel.getApplet() == null &&
> > - ((NetxPanel) panel).isAlive()) {
> > - try {
> > - Thread.sleep(50);
> > - PluginDebug.debug("Waiting for applet to initialize...");
> > - } catch (InterruptedException ie) {
> > - // just wait
> > - }
> > - }
> > + waitForAppletInit((NetxPanel) panel);
> >
> > PluginDebug.debug(panel + " -- " + panel.getApplet() + " -- " + ((NetxPanel) panel).isAlive());
> >
> > @@ -1548,10 +1682,11 @@
> > if (countApplets() == 0) {
> > appletSystemExit();
> > }
> > +
> > + updateStatus(identifier, PAV_INIT_STATUS.DESTROYED);
> > }
> > }).start();
> >
> > - status.put(identifier, PAV_INIT_STATUS.INACTIVE);
> > }
> >
> > /**
> > @@ -1677,18 +1812,6 @@
> > val = buf.toString();
> > }
> >
> > - att = att.replace(">", ">");
> > - att = att.replace("<", "<");
> > - att = att.replace("&", "&");
> > - att = att.replace(" ", "\n");
> > - att = att.replace(" ", "\r");
> > -
> > - val = val.replace(">", ">");
> > - val = val.replace("<", "<");
> > - val = val.replace("&", "&");
> > - val = val.replace(" ", "\n");
> > - val = val.replace(" ", "\r");
> > -
> > PluginDebug.debug("PUT " + att + " = '" + val + "'");
> > atts.put(att.toLowerCase(java.util.Locale.ENGLISH), val);
> >
> > @@ -1708,7 +1831,6 @@
> > // private static final == inline
> > private static final boolean isInt(Object o) {
> > boolean isInt = false;
> > -
> > try {
> > Integer.parseInt((String) o);
> > isInt = true;
> > @@ -1763,7 +1885,6 @@
> > } catch (IOException ioe) {
> > return ioe;
> > }
> > -
> > return null;
> > }
> > };
> > @@ -1785,6 +1906,7 @@
> > boolean isObjectTag = false;
> > boolean isEmbedTag = false;
> > boolean objectTagAlreadyParsed = false;
> > +
> > // The current character
> > // FIXME: This is an evil hack to force pass-by-reference.. the
> > // parsing code needs to be rewritten from scratch to prevent such
> > @@ -1879,19 +2001,6 @@
> > if (val == null) {
> > statusMsgStream.println(requiresNameWarning);
> > } else if (atts != null) {
> > - att = att.replace(">", ">");
> > - att = att.replace("<", "<");
> > - att = att.replace("&", "&");
> > - att = att.replace(" ", "\n");
> > - att = att.replace(" ", "\r");
> > - att = att.replace(""", "\"");
> > -
> > - val = val.replace(">", ">");
> > - val = val.replace("<", "<");
> > - val = val.replace("&", "&");
> > - val = val.replace(" ", "\n");
> > - val = val.replace(" ", "\r");
> > - val = val.replace(""", "\"");
> > PluginDebug.debug("PUT " + att + " = " + val);
> > atts.put(att.toLowerCase(), val);
> > } else {
> > @@ -1920,8 +2029,8 @@
> >
> > if (atts.get("width") == null || !isInt(atts.get("width"))) {
> > atts.put("width", width);
> > - }
> > -
> > + }
> > +
> > if (atts.get("height") == null || !isInt(atts.get("height"))) {
> > atts.put("height", height);
> > }
> > @@ -1974,7 +2083,7 @@
> > if (atts.get("width") == null || !isInt(atts.get("width"))) {
> > atts.put("width", width);
> > }
> > -
> > +
> > if (atts.get("height") == null || !isInt(atts.get("height"))) {
> > atts.put("height", height);
> > }
> > @@ -2023,10 +2132,11 @@
> > if (atts.get("width") == null || !isInt(atts.get("width"))) {
> > atts.put("width", width);
> > }
> > -
> > +
> > if (atts.get("height") == null || !isInt(atts.get("height"))) {
> > atts.put("height", height);
> > }
> > +
> > }
> > }
> > }
> > diff -r 85db7b3a1c93 plugin/icedteanp/java/sun/applet/PluginMessageConsumer.java
> > --- a/plugin/icedteanp/java/sun/applet/PluginMessageConsumer.java Thu Oct 21 21:12:21 2010 +0100
> > +++ b/plugin/icedteanp/java/sun/applet/PluginMessageConsumer.java Thu Oct 21 17:22:56 2010 -0700
> > @@ -126,6 +126,10 @@
> > }
> >
> > private String getPriorityStrIfPriority(String message) {
> > +
> > + // Destroy messages are permanently high priority
> > + if (message.endsWith("destroy"))
> > + return "destroy";
> >
> > synchronized (priorityWaitQueue) {
> > Iterator<String> it = priorityWaitQueue.iterator();
> > @@ -150,7 +154,6 @@
> > }
> > }
> >
> > -
> > public void notifyWorkerIsFree(PluginMessageHandlerWorker worker) {
> > synchronized (initWorkers) {
> > Iterator<Integer> i = initWorkers.keySet().iterator();
> > @@ -176,6 +179,32 @@
> > }
> >
> > protected class ConsumerThread extends Thread {
> > +
> > + /**
> > + * Scans the readQueue for priority messages and brings them to the front
> > + */
> > + private void bringPriorityMessagesToFront() {
> > + synchronized (readQueue) {
> > +
> > + // iterate through the list
> > + for (int i=0; i < readQueue.size(); i++) {
> > +
> > + // remove element at i to inspect it
> > + String message = readQueue.remove(i);
> > +
> > + // if element at i is a priority msg, bring it forward
> > + if (getPriorityStrIfPriority(message) != null) {
> > + readQueue.addFirst(message);
> > + } else { // else keep it where it was
> > + readQueue.add(i, message);
> > + }
> > +
> > + // by the end the queue size is the same, so the
> > + // position indicator (i) is still valid
> > + }
> > + }
> > + }
> > +
> > public void run() {
> >
> > while (true) {
> > @@ -190,7 +219,6 @@
> >
> > String[] msgParts = message.split(" ");
> >
> > -
> > String priorityStr = getPriorityStrIfPriority(message);
> > boolean isPriorityResponse = (priorityStr != null);
> >
> > @@ -199,9 +227,12 @@
> >
> > if (worker == null) {
> > synchronized(readQueue) {
> > - readQueue.addLast(message);
> > + readQueue.addFirst(message);
> > }
> >
> > + // re-scan to see if any priority message came in
> > + bringPriorityMessagesToFront();
> > +
> > continue; // re-loop to try next msg
> > }
> >
>
>
> --
> Andrew :)
>
> Free Java Software Engineer
> Red Hat, Inc. (http://www.redhat.com)
>
> Support Free Java!
> Contribute to GNU Classpath and the OpenJDK
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