Re: [PATCH v2 6/6] fsmonitor: add a sample query-fsmonitor hook script for Watchman

> On Thu, May 18, 2017 at 10:13 PM, Ben Peart <peartben@gmail.com> wrote:
>> This hook script integrates the new fsmonitor capabilities of git with
>> the cross platform Watchman file watching service. To use the script:
>>
>> Download and install Watchman from https://facebook.github.io/watchman/
>> and instruct Watchman to watch your working directory for changes
>> ('watchman watch-project /usr/src/git').
>>
>> Rename the sample integration hook from query-fsmonitor.sample to
>> query-fsmonitor.
>>
>> Configure git to use the extension ('git config core.fsmonitor true')
>> and optionally turn on the untracked cache for optimal performance
>> ('git config core.untrackedcache true').
>
> Ok, it looks like the untracked cache can be used, but it could work without it.
>
>> Signed-off-by: Ben Peart <benpeart@microsoft.com>
>> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
>> ---
>>  templates/hooks--query-fsmonitor.sample | 27 +++++++++++++++++++++++++++
>>  1 file changed, 27 insertions(+)
>>  create mode 100644 templates/hooks--query-fsmonitor.sample
>>
>> diff --git a/templates/hooks--query-fsmonitor.sample b/templates/hooks--query-fsmonitor.sample
>> new file mode 100644
>> index 0000000000..4bd22f21d8
>> --- /dev/null
>> +++ b/templates/hooks--query-fsmonitor.sample
>> @@ -0,0 +1,27 @@
>> +#!/bin/sh
>> +#
>> +# An example hook script to integrate Watchman
>> +# (https://facebook.github.io/watchman/) with git to provide fast
>> +# git status.
>> +#
>> +# The hook is passed a time_t formatted as a string and outputs to
>> +# stdout all files that have been modified since the given time.
>> +# Paths must be relative to the root of the working tree and
>> +# separated by a single NUL.
>> +#
>> +# To enable this hook, rename this file to "query-fsmonitor"
>> +
>> +# Convert unix style paths to escaped Windows style paths
>> +case "$(uname -s)" in
>> +MINGW*|MSYS_NT*)
>> +  GIT_WORK_TREE="$(cygpath -aw "$PWD" | sed 's,\\,\\\\,g')"
>> +  ;;
>> +*)
>> +  GIT_WORK_TREE="$PWD"
>> +  ;;
>> +esac
>> +
>> +# Query Watchman for all the changes since the requested time
>> +echo "[\"query\", \"$GIT_WORK_TREE\", {\"since\": $1, \"fields\":[\"name\"]}]" | \
>> +watchman -j | \
>> +perl -e 'use JSON::PP; my $o = JSON::PP->new->utf8->decode(join("", <>)); die "Watchman: $o->{'error'}.\nFalling back to scanning...\n" if defined($o->{"error"}); print(join("\0", @{$o->{"files"}}));'
>
> Maybe put the above small perl script on multiple lines for improved
> readability.
>
> Is JSON::PP always available in Perl >= 5.8?