Mercurial > hg
view tests/test-show.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 | e6b5e7329ff2 |
children |
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$ cat >> $HGRCPATH << EOF > [extensions] > show = > EOF No arguments shows available views $ hg init empty $ cd empty $ hg show available views: bookmarks -- bookmarks and their associated changeset stack -- current line of work work -- changesets that aren't finished abort: no view requested (use "hg show VIEW" to choose a view) [255] `hg help show` prints available views $ hg help show hg show VIEW show various repository information A requested view of repository data is displayed. If no view is requested, the list of available views is shown and the command aborts. Note: There are no backwards compatibility guarantees for the output of this command. Output may change in any future Mercurial release. Consumers wanting stable command output should specify a template via "-T/--template". List of available views: bookmarks bookmarks and their associated changeset stack current line of work work changesets that aren't finished (use 'hg help -e show' to show help for the show extension) options: -T --template TEMPLATE display with template (some details hidden, use --verbose to show complete help) Unknown view prints error $ hg show badview abort: unknown view: badview (run "hg show" to see available views) [255] HGPLAIN results in abort $ HGPLAIN=1 hg show bookmarks abort: must specify a template in plain mode (invoke with -T/--template to control output format) [255] But not if a template is specified $ HGPLAIN=1 hg show bookmarks -T '{bookmark}\n' (no bookmarks set) $ cd .. bookmarks view with no bookmarks prints empty message $ hg init books $ cd books $ touch f0 $ hg -q commit -A -m initial $ hg show bookmarks (no bookmarks set) bookmarks view shows bookmarks in an aligned table $ echo book1 > f0 $ hg commit -m 'commit for book1' $ echo book2 > f0 $ hg commit -m 'commit for book2' $ hg bookmark -r 1 book1 $ hg bookmark a-longer-bookmark $ hg show bookmarks * a-longer-bookmark 7b57 book1 b757 A custom bookmarks template works $ hg show bookmarks -T '{node} {bookmark} {active}\n' 7b5709ab64cbc34da9b4367b64afff47f2c4ee83 a-longer-bookmark True b757f780b8ffd71267c6ccb32e0882d9d32a8cc0 book1 False bookmarks JSON works $ hg show bookmarks -T json [ { "active": true, "bookmark": "a-longer-bookmark", "longestbookmarklen": 17, "node": "7b5709ab64cbc34da9b4367b64afff47f2c4ee83", "nodelen": 4 }, { "active": false, "bookmark": "book1", "longestbookmarklen": 17, "node": "b757f780b8ffd71267c6ccb32e0882d9d32a8cc0", "nodelen": 4 } ] JSON works with no bookmarks $ hg book -d a-longer-bookmark $ hg book -d book1 $ hg show bookmarks -T json [ ] commands.show.aliasprefix aliases values to `show <view>` $ hg --config commands.show.aliasprefix=s sbookmarks (no bookmarks set) $ hg --config commands.show.aliasprefix=sh shwork @ 7b57 commit for book2 o b757 commit for book1 o ba59 initial $ hg --config commands.show.aliasprefix='s sh' swork @ 7b57 commit for book2 o b757 commit for book1 o ba59 initial $ hg --config commands.show.aliasprefix='s sh' shwork @ 7b57 commit for book2 o b757 commit for book1 o ba59 initial The aliases don't appear in `hg config` $ hg --config commands.show.aliasprefix=s config alias [1] Doesn't overwrite existing alias $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s swork changeset: 2:7b5709ab64cb tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: commit for book2 $ hg --config alias.swork='log -r .' --config commands.show.aliasprefix=s config alias alias.swork=log -r . $ cd ..