name : fsmonitor-watchman.sample #!/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 2) and last update token # formatted as a string and outputs to stdout a new update token and # all files that have been modified since the update token. 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, $last_update_token) = @ARGV; # Uncomment for debugging # print STDERR "$0 $version $last_update_token\n"; # Check the hook interface version if ($version ne 2) { die "Unsupported query-fsmonitor hook version '$version'.\n" . "Falling back to scanning...\n"; } my $git_work_tree = get_working_dir(); my $retry = 1; my $json_pkg; eval { require JSON::XS; $json_pkg = "JSON::XS"; 1; } or do { require JSON::PP; $json_pkg = "JSON::PP"; }; launch_watchman(); sub launch_watchman { my $o = watchman_query(); if (is_work_tree_watched($o)) { output_result($o->{clock}, @{$o->{files}}); } } sub output_result { my ($clockid, @files) = @_; # Uncomment for debugging watchman output # open (my $fh, ">", ".git/watchman-output.out"); # binmode $fh, ":utf8"; # print $fh "$clockid\n@files\n"; # close $fh; binmode STDOUT, ":utf8"; print $clockid; print "\0"; local $, = "\0"; print @files; } sub watchman_clock { my $response = qx/watchman clock "$git_work_tree"/; die "Failed to get clock id on '$git_work_tree'.\n" . "Falling back to scanning...\n" if $? != 0; return $json_pkg->new->utf8->decode($response); } sub watchman_query { 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 $last_update_token but not from the .git folder. # # 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. my $last_update_line = ""; if (substr($last_update_token, 0, 1) eq "c") { $last_update_token = "\"$last_update_token\""; $last_update_line = qq[\n"since": $last_update_token,]; } my $query = <<" END"; ["query", "$git_work_tree", {$last_update_line "fields": ["name"], "expression": ["not", ["dirname", ".git"]] }] END # Uncomment for debugging the watchman query # open (my $fh, ">", ".git/watchman-query.json"); # print $fh $query; # close $fh; print CHLD_IN $query; close CHLD_IN; my $response = do {local $/; <CHLD_OUT>}; # Uncomment for debugging the watch response # open ($fh, ">", ".git/watchman-response.json"); # print $fh $response; # close $fh; 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 =~ /^\{/; return $json_pkg->new->utf8->decode($response); } sub is_work_tree_watched { my ($output) = @_; my $error = $output->{error}; if ($retry > 0 and $error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) { $retry--; my $response = qx/watchman watch "$git_work_tree"/; die "Failed to make watchman watch '$git_work_tree'.\n" . "Falling back to scanning...\n" if $? != 0; $output = $json_pkg->new->utf8->decode($response); $error = $output->{error}; die "Watchman: $error.\n" . "Falling back to scanning...\n" if $error; # Uncomment for debugging watchman output # open (my $fh, ">", ".git/watchman-output.out"); # close $fh; # 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. my $o = watchman_clock(); $error = $output->{error}; die "Watchman: $error.\n" . "Falling back to scanning...\n" if $error; output_result($o->{clock}, ("/")); $last_update_token = $o->{clock}; eval { launch_watchman() }; return 0; } die "Watchman: $error.\n" . "Falling back to scanning...\n" if $error; return 1; } sub get_working_dir { my $working_dir; if ($^O =~ 'msys' || $^O =~ 'cygwin') { $working_dir = Win32::GetCwd(); $working_dir =~ tr/\\/\//; } else { require Cwd; $working_dir = Cwd::cwd(); } return $working_dir; }