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view tests/test-issue1306.t @ 39561:d06834e0f48e
wireprotov2peer: stream decoded responses
Previously, wire protocol version 2 would buffer all response data.
Only once all data was received did we CBOR decode it and resolve
the future associated with the command. This was obviously not
desirable. In future commits that introduce large response payloads,
this caused significant memory bloat and slowed down client
operations due to waiting on the server.
This commit refactors the response handling code so that response
data can be streamed.
Command response objects now contain a buffered CBOR decoder. As
new data arrives, it is fed into the decoder. Decoded objects are
made available to the generator as they are decoded.
Because there is a separate thread processing incoming frames and
feeding data into the response object, there is the potential for
race conditions when mutating response objects. So a lock has been
added to guard access to critical state variables.
Because the generator emitting decoded objects needs to wait on
those objects to become available, we've added an Event for the
generator to wait on so it doesn't busy loop. This does mean
there is the potential for deadlocks. And I'm pretty sure they can
occur in some scenarios. We already have a handful of TODOs around
this. But I've added some more. Fixing this will likely require
moving the background thread receiving frames into clienthandler.
We likely would have done this anyway when implementing the client
bits for the SSH transport.
Test output changes because the initial CBOR map holding the overall
response state is now always handled internally by the response
object.
Differential Revision: https://phab.mercurial-scm.org/D4474
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 29 Aug 2018 15:17:11 -0700 |
parents | eb586ed5d8ce |
children |
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https://bz.mercurial-scm.org/1306 Initialize remote repo with branches: $ hg init remote $ cd remote $ echo a > a $ hg ci -Ama adding a $ hg branch br marked working directory as branch br (branches are permanent and global, did you want a bookmark?) $ hg ci -Amb $ echo c > c $ hg ci -Amc adding c $ hg log changeset: 2:ae3d9c30ec50 branch: br tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: c changeset: 1:3f7f930ca414 branch: br user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: b changeset: 0:cb9a9f314b8b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a $ cd .. Try cloning -r branch: $ hg clone -rbr remote local1 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files new changesets cb9a9f314b8b:ae3d9c30ec50 updating to branch br 2 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local1 parents changeset: 2:ae3d9c30ec50 branch: br tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: c Try cloning -rother clone#branch: $ hg clone -r0 remote#br local2 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files new changesets cb9a9f314b8b:ae3d9c30ec50 updating to branch default 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local2 parents changeset: 0:cb9a9f314b8b user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: a Try cloning -r1 clone#branch: $ hg clone -r1 remote#br local3 adding changesets adding manifests adding file changes added 3 changesets with 2 changes to 2 files new changesets cb9a9f314b8b:ae3d9c30ec50 updating to branch br 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg -R local3 parents changeset: 1:3f7f930ca414 branch: br user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: b