Mercurial > hg
view tests/test-record.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 | da07367d683b |
children | db72f9f6580e |
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Set up a repo $ cat <<EOF >> $HGRCPATH > [ui] > interactive = true > [extensions] > record = > EOF $ hg init a $ cd a Record help $ hg record -h hg record [OPTION]... [FILE]... interactively select changes to commit If a list of files is omitted, all changes reported by 'hg status' will be candidates for recording. See 'hg help dates' for a list of formats valid for -d/--date. If using the text interface (see 'hg help config'), you will be prompted for whether to record changes to each modified file, and for files with multiple changes, for each change to use. For each query, the following responses are possible: y - record this change n - skip this change e - edit this change manually s - skip remaining changes to this file f - record remaining changes to this file d - done, skip remaining changes and files a - record all changes to all remaining files q - quit, recording no changes ? - display help This command is not available when committing a merge. (use 'hg help -e record' to show help for the record extension) options ([+] can be repeated): -A --addremove mark new/missing files as added/removed before committing --close-branch mark a branch head as closed --amend amend the parent of the working directory -s --secret use the secret phase for committing -e --edit invoke editor on commit messages -I --include PATTERN [+] include names matching the given patterns -X --exclude PATTERN [+] exclude names matching the given patterns -m --message TEXT use text as commit message -l --logfile FILE read commit message from file -d --date DATE record the specified date as commit date -u --user USER record the specified user as committer -S --subrepos recurse into subrepositories -w --ignore-all-space ignore white space when comparing lines -b --ignore-space-change ignore changes in the amount of white space -B --ignore-blank-lines ignore changes whose lines are all blank -Z --ignore-space-at-eol ignore changes in whitespace at EOL (some details hidden, use --verbose to show complete help) Select no files $ touch empty-rw $ hg add empty-rw $ hg record empty-rw<<EOF > n > EOF diff --git a/empty-rw b/empty-rw new file mode 100644 examine changes to 'empty-rw'? [Ynesfdaq?] n no changes to record [1] $ hg tip -p changeset: -1:000000000000 tag: tip user: date: Thu Jan 01 00:00:00 1970 +0000