Changeset 11444 in josm

Timestamp:

2017-01-09T00:34:05+01:00 (8 years ago)

Author:

wiktorn

Message:

Fix disappearing download tasks.

When ThreadPoolExecutor is adapting it's size, it interrupts its threads from time to time. HostLimitQueue had a bug, that when interrupted when waiting to acquire lock, it didn't return the job back to the queue.

Added testcases that helped debug this and that verify, that we're actually doing host based limiting.

Sponsored by "Girl, interrupted" movie with Angelina Jolie.

See: #14166

Location:

trunk

Files:

• src/org/openstreetmap/josm/data/cache/HostLimitQueue.java (modified) (3 diffs)
• test/unit/org/openstreetmap/josm/data/cache/HostLimitQueueTest.java (added)

trunk/src/org/openstreetmap/josm/data/cache/HostLimitQueue.java

@@ -84 +84 @@
         job = pollFirst(timeout, unit);
         if (job != null) {
-            acquireSemaphore(job);
+            try {
+                boolean gotLock = tryAcquireSemaphore(job, timeout, unit);
+                return gotLock ? job : null;
+            } catch (InterruptedException e) {
+                // acquire my got interrupted, first offer back what was taken
+                offer(job);
+                throw e;
+            }
         }
         return job;
@@ -96 +103 @@
         }
         job = takeFirst();
-        acquireSemaphore(job);
+        try {
+            acquireSemaphore(job);
+        } catch (InterruptedException e) {
+            // acquire my got interrupted, first offer back what was taken
+            offer(job);
+            throw e;
+        }
         return job;
     }
@@ -176 +189 @@
     }
 
+    private boolean tryAcquireSemaphore(Runnable job, long timeout, TimeUnit unit) throws InterruptedException {
+        boolean ret = true;
+        if (job instanceof JCSCachedTileLoaderJob) {
+            final JCSCachedTileLoaderJob<?, ?> jcsJob = (JCSCachedTileLoaderJob<?, ?>) job;
+            Semaphore limit = getSemaphore(jcsJob);
+            if (limit != null) {
+                ret = limit.tryAcquire(timeout, unit);
+                if (ret) {
+                    jcsJob.setFinishedTask(() -> releaseSemaphore(jcsJob));
+                }
+            }
+        }
+        return ret;
+    }
+
     private void releaseSemaphore(JCSCachedTileLoaderJob<?, ?> job) {
         Semaphore limit = getSemaphore(job);