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markt pushed a commit to branch 8.5.x
in repository https://gitbox.apache.org/repos/asf/tomcat.git
The following commit(s) were added to refs/heads/8.5.x by this push:
new 67c4c72 Refactor int[] to class to improve maintainability #
Conflicts: # java/org/apache/coyote/http2/Http2UpgradeHandler.java
67c4c72 is described below
commit 67c4c72f6e51bf1c0cfa1d10c115962be1a8fe0a
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Thu May 30 21:09:10 2019 +0100
Refactor int[] to class to improve maintainability
# Conflicts:
# java/org/apache/coyote/http2/Http2UpgradeHandler.java
---
.../apache/coyote/http2/Http2UpgradeHandler.java | 150 ++++++++++++++-------
1 file changed, 99 insertions(+), 51 deletions(-)
diff --git a/java/org/apache/coyote/http2/Http2UpgradeHandler.java
b/java/org/apache/coyote/http2/Http2UpgradeHandler.java
index a1aa77c..22ea45f 100644
--- a/java/org/apache/coyote/http2/Http2UpgradeHandler.java
+++ b/java/org/apache/coyote/http2/Http2UpgradeHandler.java
@@ -138,26 +138,7 @@ public class Http2UpgradeHandler extends AbstractStream
implements InternalHttpU
private final AtomicInteger nextLocalStreamId = new AtomicInteger(2);
private final PingManager pingManager = new PingManager();
private volatile int newStreamsSinceLastPrune = 0;
- // Tracking for when the connection is blocked (windowSize < 1)
- // The int array must have 3 elements. There are:
- // [0] - The number of bytes the Stream requires from the connection
- // window. This excludes any allocation that has already been made.
- // [1] - The number of bytes that has been allocated from the connection
- // window. This excludes any bytes that have been written since the
- // allocation was made.
- // [2] - 1 if the stream thread has been notified that an allocation has
- // been made but has not yet consumed that allocation. 0 in all
- // other cases. The purpose of this is to avoid the incorrect
- // triggering of a timeout for the following sequence of events:
- // window update 1
- // allocation 1
- // notify 1
- // window update 2
- // allocation 2
- // act on notify 1 (using allocation 1 and 2)
- // notify 2
- // act on notify 2 (timeout due to no allocation)
- private final ConcurrentMap<AbstractStream,int[]> backLogStreams = new
ConcurrentHashMap<>();
+ private final ConcurrentMap<AbstractStream, BacklogTracker> backLogStreams
= new ConcurrentHashMap<>();
private long backLogSize = 0;
// Stream concurrency control
@@ -785,21 +766,21 @@ public class Http2UpgradeHandler extends AbstractStream
implements InternalHttpU
long windowSize = getWindowSize();
if (windowSize < 1 || backLogSize > 0) {
// Has this stream been granted an allocation
- int[] value = backLogStreams.get(stream);
- if (value == null) {
- value = new int[] { reservation, 0, 0 };
- backLogStreams.put(stream, value);
+ BacklogTracker tracker = backLogStreams.get(stream);
+ if (tracker == null) {
+ tracker = new BacklogTracker(reservation);
+ backLogStreams.put(stream, tracker);
backLogSize += reservation;
// Add the parents as well
AbstractStream parent = stream.getParentStream();
- while (parent != null &&
backLogStreams.putIfAbsent(parent, new int[3]) == null) {
+ while (parent != null &&
backLogStreams.putIfAbsent(parent, new BacklogTracker()) == null) {
parent = parent.getParentStream();
}
} else {
- if (value[1] > 0) {
- allocation = value[1];
+ if (tracker.getUnusedAllocation() > 0) {
+ allocation = tracker.getUnusedAllocation();
decrementWindowSize(allocation);
- if (value[0] == 0) {
+ if (tracker.getRemainingReservation() == 0) {
// The reservation has been fully allocated
// so this stream can be removed from the
// backlog.
@@ -808,10 +789,7 @@ public class Http2UpgradeHandler extends AbstractStream
implements InternalHttpU
// This allocation has been used. Leave the
// stream on the backlog as it still has
// more bytes to write.
- // Reset the allocation to zero.
- value[1] = 0;
- // Clear the notify in progress marker
- value[2] = 0;
+ tracker.useAllocation();
}
}
}
@@ -837,12 +815,12 @@ public class Http2UpgradeHandler extends AbstractStream
implements InternalHttpU
// Has this stream been granted an allocation
// Note: If the stream in not in this Map then
the
// requested write has been fully
allocated
- int[] value;
+ BacklogTracker tracker;
// Ensure allocations made in other threads
are visible
synchronized (this) {
- value = backLogStreams.get(stream);
+ tracker = backLogStreams.get(stream);
}
- if (value != null && value[1] == 0) {
+ if (tracker != null &&
tracker.getUnusedAllocation() == 0) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("upgradeHandler.noAllocation",
connectionId,
stream.getIdentifier()));
@@ -938,13 +916,13 @@ public class Http2UpgradeHandler extends AbstractStream
implements InternalHttpU
while (leftToAllocate > 0) {
leftToAllocate = allocate(this, leftToAllocate);
}
- for (Entry<AbstractStream,int[]> entry :
backLogStreams.entrySet()) {
- int allocation = entry.getValue()[1];
+ for (Entry<AbstractStream,BacklogTracker> entry :
backLogStreams.entrySet()) {
+ int allocation = entry.getValue().getUnusedAllocation();
if (allocation > 0) {
backLogSize -= allocation;
- if (entry.getValue()[2] == 0) {
+ if (!entry.getValue().isNotifyInProgress()) {
result.add(entry.getKey());
- entry.getValue()[2] = 1;
+ entry.getValue().startNotify();
}
}
}
@@ -967,20 +945,14 @@ public class Http2UpgradeHandler extends AbstractStream
implements InternalHttpU
stream.getIdentifier(), Integer.toString(allocation)));
}
// Allocate to the specified stream
- int[] value = backLogStreams.get(stream);
- if (value[0] >= allocation) {
- value[0] -= allocation;
- value[1] += allocation;
+ BacklogTracker tracker = backLogStreams.get(stream);
+
+ int leftToAllocate = tracker.allocate(allocation);
+
+ if (leftToAllocate == 0) {
return 0;
}
- // There was some left over so allocate that to the children of the
- // stream.
- int leftToAllocate = allocation;
- value[1] = value[0];
- value[0] = 0;
- leftToAllocate -= value[1];
-
if (log.isDebugEnabled()) {
log.debug(sm.getString("upgradeHandler.allocate.left",
getConnectionId(), stream.getIdentifier(),
Integer.toString(leftToAllocate)));
@@ -1804,5 +1776,81 @@ public class Http2UpgradeHandler extends AbstractStream
implements InternalHttpU
public boolean isNewStreamAllowed() {
return newStreamsAllowed;
}
- }
+ }
+
+
+ private static class BacklogTracker {
+
+ private int remainingReservation;
+ private int unusedAllocation;
+ private boolean notifyInProgress;
+
+ public BacklogTracker() {
+ }
+
+ public BacklogTracker(int reservation) {
+ remainingReservation = reservation;
+ }
+
+ /**
+ * @return The number of bytes requiring an allocation from the
+ * Connection flow control window
+ */
+ public int getRemainingReservation() {
+ return remainingReservation;
+ }
+
+ /**
+ *
+ * @return The number of bytes allocated from the Connection flow
+ * control window but not yet written
+ */
+ public int getUnusedAllocation() {
+ return unusedAllocation;
+ }
+
+ /**
+ * The purpose of this is to avoid the incorrect triggering of a
timeout
+ * for the following sequence of events:
+ * <ol>
+ * <li>window update 1</li>
+ * <li>allocation 1</li>
+ * <li>notify 1</li>
+ * <li>window update 2</li>
+ * <li>allocation 2</li>
+ * <li>act on notify 1 (using allocation 1 and 2)</li>
+ * <li>notify 2</li>
+ * <li>act on notify 2 (timeout due to no allocation)</li>
+ * </ol>
+ *
+ * @return {@code true} if a notify has been issued but the associated
+ * allocation has not been used, otherwise {@code false}
+ */
+ public boolean isNotifyInProgress() {
+ return notifyInProgress;
+ }
+
+ public void useAllocation() {
+ unusedAllocation = 0;
+ notifyInProgress = false;
+ }
+
+ public void startNotify() {
+ notifyInProgress = true;
+ }
+
+ private int allocate(int allocation) {
+ if (remainingReservation >= allocation) {
+ remainingReservation -= allocation;
+ unusedAllocation += allocation;
+ return 0;
+ }
+
+ int left = allocation - remainingReservation;
+ unusedAllocation += remainingReservation;
+ remainingReservation = 0;
+
+ return left;
+ }
+ }
}
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