Motivation:
We can replace some "hand-rolled" integer checks with our own static utility method to simplify the code.
Modifications:
Use methods provided by `ObjectUtil`.
Result:
Cleaner code and less duplication
Motivation:
Currently the remote flow controller limits the maximum amount of pending data to Integer.MAX_VALUE. The overflow handling is also not very graceful in that it may lead to infinite loops, or otherwise no progress being made.
Modifications:
- StreamByteDistributor and RemoteFlowController should support pending bytes of type long.
Result:
Fixes https://github.com/netty/netty/issues/4283
Motivation:
Objects of java.util.TreeMap or java.util.TreeSet will become
non-Serializable if instantiated with Comparators, which are not also
Serializable. This can result in unexpected and difficult-to-diagnose
bugs.
Modifications:
Implements Serializable for all classes, which implements Comparator.
Result:
Proper Comparators which will not force collections to
non-Serializable mode.
Motivation:
Each StreamByteDistributor may allow for priority in different ways, but there are certain characteristics which are invalid regardless of the distribution algorithm. We should validate these invalid characteristics at the flow controller level.
Modifications:
- Disallow negative stream IDs from being used. These streams may be accepted by the WeightedFairQueueByteDistributor and cause state for other valid streams to be evicted.
- Improve unit tests to verify limits are enforced.
Result:
Boundary conditions related to the priority parameters are validated more strictly.
Motivation:
Chrome was randomly getting stuck loading the tiles examples.
Investigation showed that the Netty flow controller thought it had
nothing to send for the connection even though some streams has queued
data and window available.
Modifications:
Fixed an accounting error where an implicitly created parent was not
being added to the dependency tree, thus it and all of its children were
orphaned from the connection's tree and would never have data written.
Result:
Fixes#6621
Motivation:
Although effectively unused, the toString() of
WeightedFairQueueByteDistributor.State is useful for debugging. It
accidentally had an infinite loop, as it would recurse infinitely
between a parent and its child, which makes it less useful for
debugging.
Modifications:
Prune the infinite loop by using the parent's streamId instead of the
parent's toString().
Result:
Faster, less stack-overflowing toString()
Motivation:
codec-http2 couples the dependency tree state with the remainder of the stream state (Http2Stream). This makes implementing constraints where stream state and dependency tree state diverge in the RFC challenging. For example the RFC recommends retaining dependency tree state after a stream transitions to closed [1]. Dependency tree state can be exchanged on streams in IDLE. In practice clients may use stream IDs for the purpose of establishing QoS classes and therefore retaining this dependency tree state can be important to client perceived performance. It is difficult to limit the total amount of state we retain when stream state and dependency tree state is combined.
Modifications:
- Remove dependency tree, priority, and weight related items from public facing Http2Connection and Http2Stream APIs. This information is optional to track and depends on the flow controller implementation.
- Move all dependency tree, priority, and weight related code from DefaultHttp2Connection to WeightedFairQueueByteDistributor. This is currently the only place which cares about priority. We can pull out the dependency tree related code in the future if it is generally useful to expose for other implementations.
- DefaultHttp2Connection should explicitly limit the number of reserved streams now that IDLE streams are no longer created.
Result:
More compliant with the HTTP/2 RFC.
Fixes https://github.com/netty/netty/issues/6206.
[1] https://tools.ietf.org/html/rfc7540#section-5.3.4
Motivation:
If a stream is not able to send any data (flow control window for the stream is exhausted) but has descendants who can send data then WeightedFairQueueByteDistributor may incorrectly modify the pseudo time and also double add the associated state to the parent's priority queue. The pseudo time should only be modified if a node is moved in the priority tree, and not if there happens to be no active streams in its descendent tree and a descendent is moved (e.g. removed from the tree because it wrote all data and the last data frame was EOS). Also the state objects for WeightedFairQueueByteDistributor should only appear once in any queue. If this condition is violated the pseudo time accounting would be biased at and assumptions in WeightedFairQueueByteDistributor would be invalidated.
Modifications:
- WeightedFairQueueByteDistributor#isActiveCountChangeForTree should not allow re-adding to the priority queue if we are currently processing a node in the distribution algorithm. The distribution algorithm will re-evaluate if the node should be re-added on the tail end of the recursion.
Result:
Fixes https://github.com/netty/netty/issues/5980
Motivation:
Some codecs should be considered unstable as these are relative new. For this purpose we should introduce an annotation which these codecs should us to be marked as unstable in terms of API.
Modifications:
- Add UnstableApi annotation and use it on codecs that are not stable
- Move http2.hpack to http2.internal.hpack as it is internal.
Result:
Better document unstable APIs.
Motivation:
Javadoc reports errors about invalid docs.
Modifications:
Fix some errors reported by javadoc.
Result:
A lot of javadoc errors are fixed by this patch.
Motivation:
There are some wrong links and tags in javadoc.
Modifications:
Fix the wrong links and tags in javadoc.
Result:
These links will work correctly in javadoc.
Motivation:
DefaultHttp2RemoteFlowController.ListenerWritabilityMonitor no longer reliably detects when a stream's writability change occurs.
Modifications:
- Ensure writiability is reliabily reported by DefaultHttp2RemoteFlowController.ListenerWritabilityMonitor
- Fix infinite loop issue (https://github.com/netty/netty/issues/4588) detected when consolidating unit tests
Result:
Reliable stream writability change notification, and 1 less infinite loop in UniformStreamByteDistributor.
Fixes https://github.com/netty/netty/issues/4587
Motivation:
PriorityStreamByteDistributor uses a homegrown algorithm which distributes bytes to nodes in the priority tree. PriorityStreamByteDistributor has no concept of goodput which may result in poor utilization of network resources. PriorityStreamByteDistributor also has performance issues related to the tree traversal approach and number of nodes that must be visited. There also exists some more proven algorithms from the resource scheduling domain which PriorityStreamByteDistributor does not employ.
Modifications:
- Introduce a new ByteDistributor which uses elements from weighted fair queue schedulers
Result:
StreamByteDistributor which is sensitive to priority and uses a more familiar distribution concept.
Fixes https://github.com/netty/netty/issues/4462
