Mercurial > public > mercurial-scm > hg
comparison mercurial/debugcommands.py @ 37007:143219fc2620
debugcommands: introduce actions to perform deterministic reads
"readavailable" is useful as a debugging device to see what data is
available on a pipe. But the mechanism isn't deterministic because
what's available on a pipe is highly conditional on timing, system
load, OS behavior, etc. This makes it not suitable for tests.
We introduce "ereadline," "read," and "eread" for performing
deterministic I/O operations (at least on blocking file descriptors).
We stop short of converting existing consumers of "readavailable"
in tests because we're working out race conditions and deadlocks
on Windows. But the goal is to eventually move tests away from
"readavailable" to these new APIs.
Differential Revision: https://phab.mercurial-scm.org/D2720
| author | Gregory Szorc <gregory.szorc@gmail.com> |
|---|---|
| date | Mon, 12 Mar 2018 15:49:02 -0700 |
| parents | 317382151ac3 |
| children | fc8939825632 |
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| 37006:8e89c2bec1f7 | 37007:143219fc2620 |
|---|---|
| 2713 readline | 2713 readline |
| 2714 -------- | 2714 -------- |
| 2715 | 2715 |
| 2716 Read a line of output from the server. If there are multiple output | 2716 Read a line of output from the server. If there are multiple output |
| 2717 pipes, reads only the main pipe. | 2717 pipes, reads only the main pipe. |
| 2718 | |
| 2719 ereadline | |
| 2720 --------- | |
| 2721 | |
| 2722 Like ``readline``, but read from the stderr pipe, if available. | |
| 2723 | |
| 2724 read <X> | |
| 2725 -------- | |
| 2726 | |
| 2727 ``read()`` N bytes from the server's main output pipe. | |
| 2728 | |
| 2729 eread <X> | |
| 2730 --------- | |
| 2731 | |
| 2732 ``read()`` N bytes from the server's stderr pipe, if available. | |
| 2718 """ | 2733 """ |
| 2719 opts = pycompat.byteskwargs(opts) | 2734 opts = pycompat.byteskwargs(opts) |
| 2720 | 2735 |
| 2721 if opts['localssh'] and not repo: | 2736 if opts['localssh'] and not repo: |
| 2722 raise error.Abort(_('--localssh requires a repository')) | 2737 raise error.Abort(_('--localssh requires a repository')) |
| 2853 stdin.close() | 2868 stdin.close() |
| 2854 stdout.read() | 2869 stdout.read() |
| 2855 stderr.read() | 2870 stderr.read() |
| 2856 elif action == 'readline': | 2871 elif action == 'readline': |
| 2857 stdout.readline() | 2872 stdout.readline() |
| 2873 elif action == 'ereadline': | |
| 2874 stderr.readline() | |
| 2875 elif action.startswith('read '): | |
| 2876 count = int(action.split(' ', 1)[1]) | |
| 2877 stdout.read(count) | |
| 2878 elif action.startswith('eread '): | |
| 2879 count = int(action.split(' ', 1)[1]) | |
| 2880 stderr.read(count) | |
| 2858 else: | 2881 else: |
| 2859 raise error.Abort(_('unknown action: %s') % action) | 2882 raise error.Abort(_('unknown action: %s') % action) |
| 2860 | 2883 |
| 2861 if batchedcommands is not None: | 2884 if batchedcommands is not None: |
| 2862 raise error.Abort(_('unclosed "batchbegin" request')) | 2885 raise error.Abort(_('unclosed "batchbegin" request')) |