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- #!/usr/bin/perl
-
- use strict;
- use warnings;
- use IPC::Open2;
-
- # An example hook script to integrate Watchman
- # (https://facebook.github.io/watchman/) with git to speed up detecting
- # new and modified files.
- #
- # The hook is passed a version (currently 1) and a time in nanoseconds
- # 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-watchman" and set
- # 'git config core.fsmonitor .git/hooks/query-watchman'
- #
- my ($version, $time) = @ARGV;
-
- # Check the hook interface version
-
- if ($version == 1) {
- # convert nanoseconds to seconds
- $time = int $time / 1000000000;
- } else {
- die "Unsupported query-fsmonitor hook version '$version'.\n" .
- "Falling back to scanning...\n";
- }
-
- my $git_work_tree;
- if ($^O =~ 'msys' || $^O =~ 'cygwin') {
- $git_work_tree = Win32::GetCwd();
- $git_work_tree =~ tr/\\/\//;
- } else {
- require Cwd;
- $git_work_tree = Cwd::cwd();
- }
-
- my $retry = 1;
-
- launch_watchman();
-
- sub launch_watchman {
-
- my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')
- or die "open2() failed: $!\n" .
- "Falling back to scanning...\n";
-
- # In the query expression below we're asking for names of files that
- # changed since $time but were not transient (ie created after
- # $time but no longer exist).
- #
- # To accomplish this, we're using the "since" generator to use the
- # recency index to select candidate nodes and "fields" to limit the
- # output to file names only. Then we're using the "expression" term to
- # further constrain the results.
- #
- # The category of transient files that we want to ignore will have a
- # creation clock (cclock) newer than $time_t value and will also not
- # currently exist.
-
- my $query = <<" END";
- ["query", "$git_work_tree", {
- "since": $time,
- "fields": ["name"],
- "expression": ["not", ["allof", ["since", $time, "cclock"], ["not", "exists"]]]
- }]
- END
-
- print CHLD_IN $query;
- close CHLD_IN;
- my $response = do {local $/; <CHLD_OUT>};
-
- die "Watchman: command returned no output.\n" .
- "Falling back to scanning...\n" if $response eq "";
- die "Watchman: command returned invalid output: $response\n" .
- "Falling back to scanning...\n" unless $response =~ /^\{/;
-
- my $json_pkg;
- eval {
- require JSON::XS;
- $json_pkg = "JSON::XS";
- 1;
- } or do {
- require JSON::PP;
- $json_pkg = "JSON::PP";
- };
-
- my $o = $json_pkg->new->utf8->decode($response);
-
- if ($retry > 0 and $o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) {
- print STDERR "Adding '$git_work_tree' to watchman's watch list.\n";
- $retry--;
- qx/watchman watch "$git_work_tree"/;
- die "Failed to make watchman watch '$git_work_tree'.\n" .
- "Falling back to scanning...\n" if $? != 0;
-
- # Watchman will always return all files on the first query so
- # return the fast "everything is dirty" flag to git and do the
- # Watchman query just to get it over with now so we won't pay
- # the cost in git to look up each individual file.
- print "/\0";
- eval { launch_watchman() };
- exit 0;
- }
-
- die "Watchman: $o->{error}.\n" .
- "Falling back to scanning...\n" if $o->{error};
-
- binmode STDOUT, ":utf8";
- local $, = "\0";
- print @{$o->{files}};
- }
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