Buffer channelReads in ResponseStreamState until the next channelReadComplete
#388
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Lukasa
reviewed
Jul 6, 2021
| case waitingForRead(CircularBuffer<ByteBuffer>) | ||
| /// The state machines expects a call to `demandMoreResponseBodyParts`. The buffer is empty. It is | ||
| /// preserved for performance reasons. | ||
| case waitingForDemand(CircularBuffer<ByteBuffer>) |
There was a problem hiding this comment.
By making this a mini-state-machine, I recommend going the whole way: pull this out to a file and give it a bunch of methods that correspond to the events that can occur to it (e.g. func read). Then, the bigger state machine can just call those.
fabianfett
force-pushed
the
ff-buffer-in-channel
branch
from
d76029f to
96fbbbd
Compare
fabianfett
changed the title
channelReads in the HTTPRequestStateMachine until the next channelReadCompletechannelReads in ResponseStreamState until the next channelReadComplete
Lukasa
reviewed
Jul 7, 2021
| private var state: State | ||
|
|
||
| init(expectingBody: Bool) { | ||
| self.state = .waitingForBytes(CircularBuffer(initialCapacity: expectingBody ? 16 : 0)) |
There was a problem hiding this comment.
Given that there is no such thing as an empty circular buffer (initialCapacity: 0 still allocates) we may as well skip the branch and just always set 16.
| mutating func end() -> CircularBuffer<ByteBuffer> { | ||
| switch self.state { | ||
| case .waitingForBytes(let buffer): | ||
| // This should never happen. But we don't want to precondition this behavior. Let's just |
| expectingBody = true | ||
| } | ||
| } else if head.headers.contains(name: "transfer-encoding") { | ||
| expectingBody = true |
There was a problem hiding this comment.
We can delete this code per my above comment.
fabianfett
force-pushed
the
ff-buffer-in-channel
branch
from
2c49141 to
a4fba69
Compare
Lukasa
approved these changes
Jul 7, 2021
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Motivation
After a lengthy offline discussion @Lukasa, we concluded that it would be best, if the
HTTPRequestStateMachinewould buffer up all reads until the nextchannelReadComplete. The main reason is, we minimize potential cross thread communication, by passing collected byteBuffers onward.Modifications
ConsumerControlStatewas replaced withResponseStreamStatechannelReads are buffered up to achannelReadComplete.channelReadCompleteall buffered body parts are forwarded to the consumer