[icedtea-web] RFC: Patch to use wait() when waiting for conditions to become true
Deepak Bhole
dbhole at redhat.com
Wed Apr 13 17:48:03 PDT 2011
Hi,
Andrew mentioned in one of the previous threads that the current plugin
code waits in an inefficient manner. It wakes up periodically to
check for conditions, and goes back to sleep, and keeps doing that
cyclically.
The attached patch uses a new function that uses object.wait for
the object of interest.
ChangeLog:
2011-04-13 Deepak Bhole <dbhole at redhat.com>
* plugin/icedteanp/java/sun/applet/PluginAppletViewer.java (createPanel):
use Object.wait() to wait, rather than pariodic sleep.
(framePanel): Notify threads waiting on the applets map instance.
(appletStateChanged): Notify all threads waiting on the panel that just
changed state.
(handleMessage): Use the new waitTillTimeout function to wait, rather than
periodically waking up.
(updateStatus): Notify all threads waiting on status map.
(waitForAppletInit): Use the new waitTillTimeout function to wait, rather
than periodically waking up.
(waitTillTimeout): New function. For a given non-null object, waits until
the specified timeout, or, if an interrupt was thrown during wait, returns
immediately.
The patch is based on top of Denis's lastest refactoring patch (since a lot of
the surrounding code was touched and that patch will most likely go in very soon).
Comments?
Cheers,
Deepak
-------------- next part --------------
diff -r 2ef65ff10619 plugin/icedteanp/java/sun/applet/PluginAppletViewer.java
--- a/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java Wed Apr 13 19:17:21 2011 -0400
+++ b/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java Wed Apr 13 20:39:23 2011 -0400
@@ -91,12 +91,10 @@
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
-import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
-import java.util.List;
import java.util.Map;
import java.util.Vector;
import java.util.concurrent.ConcurrentHashMap;
@@ -142,15 +140,17 @@
initEventQueue(panel);
// Wait for panel to come alive
- int maxWait = PluginAppletViewer.APPLET_TIMEOUT; // wait for panel to come alive
- int wait = 0;
- while (!panel.isAlive() && wait < maxWait) {
+ // Wait implemented the long way so that
+ // PluginAppletViewer.waitTillTimeout() needn't be exposed.
+ long maxTimeToSleep = PluginAppletViewer.APPLET_TIMEOUT;
+ while (!panel.isAlive() && maxTimeToSleep > 0) {
+ long sleepStart = System.currentTimeMillis();
+
try {
- Thread.sleep(50);
- wait += 50;
- } catch (InterruptedException ie) {
- // just wait
- }
+ panel.wait(maxTimeToSleep);
+ } catch (InterruptedException e) {} // Just loop back
+
+ maxTimeToSleep -= (System.currentTimeMillis() - sleepStart);
}
// Wait for the panel to initialize
@@ -307,6 +307,10 @@
panel.addAppletListener(appletFrame.appletEventListener);
applets.put(identifier, appletFrame);
+
+ synchronized(applets) {
+ applets.notifyAll();
+ }
PluginDebug.debug(panel, " framed");
}
@@ -357,6 +361,11 @@
public void appletStateChanged(AppletEvent evt) {
AppletPanel src = (AppletPanel) evt.getSource();
+ PluginDebug.debug("Notifying all for ", src);
+ synchronized (src) {
+ src.notifyAll();
+ }
+
switch (evt.getID()) {
case AppletPanel.APPLET_RESIZE: {
if (src != null) {
@@ -448,21 +457,14 @@
new StringReader(tag),
new URL(documentBase));
- int maxWait = APPLET_TIMEOUT; // wait for applet to fully load
- int wait = 0;
- while (!applets.containsKey(identifier) && // Map is populated only by reFrame
- (wait < maxWait)) {
-
- try {
- Thread.sleep(50);
- wait += 50;
- } catch (InterruptedException ie) {
- // just wait
- }
+ long maxTimeToSleep = APPLET_TIMEOUT;
+ while (!applets.containsKey(identifier) &&
+ maxTimeToSleep > 0) { // Map is populated only by reFrame
+ maxTimeToSleep -= waitTillTimeout(applets, maxTimeToSleep);
}
// If wait exceeded maxWait, we timed out. Throw an exception
- if (wait >= maxWait)
+ if (maxTimeToSleep <= 0)
throw new Exception("Applet initialization timeout");
// We should not try to destroy an applet during
@@ -547,6 +549,10 @@
// Else set to given status
status.put(identifier, newStatus);
+
+ synchronized(status) {
+ status.notifyAll();
+ }
return prev;
}
@@ -599,7 +605,9 @@
}
/**
- * Function to block until applet initialization is complete
+ * Function to block until applet initialization is complete.
+ *
+ * This function will return if the wait is longer than {@link #APPLET_TIMEOUT}
*
* @param panel the instance to wait for.
*/
@@ -608,17 +616,12 @@
int waitTime = 0;
// Wait till initialization finishes
+ long maxTimeToSleep = APPLET_TIMEOUT;
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
- }
+ maxTimeToSleep > 0) {
+ PluginDebug.debug("Waiting for applet panel ", panel, " to initialize...");
+ maxTimeToSleep -= waitTillTimeout(panel, maxTimeToSleep);
}
PluginDebug.debug("Applet panel ", panel, " initialized");
@@ -628,15 +631,10 @@
if (message.startsWith("width")) {
// Wait for panel to come alive
- int maxWait = APPLET_TIMEOUT; // wait for panel to come alive
- 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
- }
+ int maxTimeToSleep = APPLET_TIMEOUT;
+ while (!status.get(identifier).equals(PAV_INIT_STATUS.INIT_COMPLETE) &&
+ maxTimeToSleep > 0) {
+ maxTimeToSleep -= waitTillTimeout(status, maxTimeToSleep);
}
// 0 => width, 1=> width_value, 2 => height, 3=> height_value
@@ -688,16 +686,16 @@
Object o;
// Wait for panel to come alive
- int maxWait = APPLET_TIMEOUT; // wait for panel to come alive
- int wait = 0;
- while ((panel == null) || (!panel.isAlive() && wait < maxWait)) {
- try {
- Thread.sleep(50);
- wait += 50;
- } catch (InterruptedException ie) {
- // just wait
- }
- }
+ long maxTimeToSleep = APPLET_TIMEOUT;
+
+ // First, wait for panel to instantiate
+ while (panel == null && maxTimeToSleep > 0)
+ maxTimeToSleep -= waitTillTimeout(panel, maxTimeToSleep);
+
+ // Next, wait for panel to come alive
+ maxTimeToSleep = APPLET_TIMEOUT;
+ while (!panel.isAlive())
+ maxTimeToSleep -= waitTillTimeout(panel, maxTimeToSleep);
// Wait for the panel to initialize
// (happens in a separate thread)
@@ -2049,4 +2047,35 @@
// Draw the painted image
g.drawImage(bufFrameImg, 0, 0, this);
}
+
+ /**
+ * Waits on a given object until timeout.
+ *
+ * If the given object is null, this function returns immediately.
+ *
+ * @param obj The object to wait on
+ * @param timeout The maximum time to wait
+ * @return Approximate time spend sleeping (not guaranteed to be perfect)
+ */
+ public static long waitTillTimeout(Object obj, long timeout) {
+
+ // Can't wait on null. Return 0 indicating no wait happened.
+ if (obj == null)
+ return 0;
+
+ // Record when we started sleeping
+ long sleepStart = System.currentTimeMillis();
+
+ try {
+ synchronized(obj) {
+ obj.wait(timeout);
+ }
+ } catch (InterruptedException ie) {} // Discarded, time to return
+
+ // Record when we woke up
+ long sleepEnd = System.currentTimeMillis();
+
+ // Return the difference
+ return sleepEnd - sleepStart;
+ }
}
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