The seventeenth batch
[git.git] / templates / hooks--fsmonitor-watchman.sample
blob14ed0aa42de0f291c0f696922110e70544c3dae2
1 #!/usr/bin/perl
3 use strict;
4 use warnings;
5 use IPC::Open2;
7 # An example hook script to integrate Watchman
8 # (https://facebook.github.io/watchman/) with git to speed up detecting
9 # new and modified files.
11 # The hook is passed a version (currently 2) and last update token
12 # formatted as a string and outputs to stdout a new update token and
13 # all files that have been modified since the update token. Paths must
14 # be relative to the root of the working tree and separated by a single NUL.
16 # To enable this hook, rename this file to "query-watchman" and set
17 # 'git config core.fsmonitor .git/hooks/query-watchman'
19 my ($version, $last_update_token) = @ARGV;
21 # Uncomment for debugging
22 # print STDERR "$0 $version $last_update_token\n";
24 # Check the hook interface version
25 if ($version ne 2) {
26 die "Unsupported query-fsmonitor hook version '$version'.\n" .
27 "Falling back to scanning...\n";
30 my $git_work_tree = get_working_dir();
32 my $retry = 1;
34 my $json_pkg;
35 eval {
36 require JSON::XS;
37 $json_pkg = "JSON::XS";
39 } or do {
40 require JSON::PP;
41 $json_pkg = "JSON::PP";
44 launch_watchman();
46 sub launch_watchman {
47 my $o = watchman_query();
48 if (is_work_tree_watched($o)) {
49 output_result($o->{clock}, @{$o->{files}});
53 sub output_result {
54 my ($clockid, @files) = @_;
56 # Uncomment for debugging watchman output
57 # open (my $fh, ">", ".git/watchman-output.out");
58 # binmode $fh, ":utf8";
59 # print $fh "$clockid\n@files\n";
60 # close $fh;
62 binmode STDOUT, ":utf8";
63 print $clockid;
64 print "\0";
65 local $, = "\0";
66 print @files;
69 sub watchman_clock {
70 my $response = qx/watchman clock "$git_work_tree"/;
71 die "Failed to get clock id on '$git_work_tree'.\n" .
72 "Falling back to scanning...\n" if $? != 0;
74 return $json_pkg->new->utf8->decode($response);
77 sub watchman_query {
78 my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')
79 or die "open2() failed: $!\n" .
80 "Falling back to scanning...\n";
82 # In the query expression below we're asking for names of files that
83 # changed since $last_update_token but not from the .git folder.
85 # To accomplish this, we're using the "since" generator to use the
86 # recency index to select candidate nodes and "fields" to limit the
87 # output to file names only. Then we're using the "expression" term to
88 # further constrain the results.
89 if (substr($last_update_token, 0, 1) eq "c") {
90 $last_update_token = "\"$last_update_token\"";
92 my $query = <<" END";
93 ["query", "$git_work_tree", {
94 "since": $last_update_token,
95 "fields": ["name"],
96 "expression": ["not", ["dirname", ".git"]]
98 END
100 # Uncomment for debugging the watchman query
101 # open (my $fh, ">", ".git/watchman-query.json");
102 # print $fh $query;
103 # close $fh;
105 print CHLD_IN $query;
106 close CHLD_IN;
107 my $response = do {local $/; <CHLD_OUT>};
109 # Uncomment for debugging the watch response
110 # open ($fh, ">", ".git/watchman-response.json");
111 # print $fh $response;
112 # close $fh;
114 die "Watchman: command returned no output.\n" .
115 "Falling back to scanning...\n" if $response eq "";
116 die "Watchman: command returned invalid output: $response\n" .
117 "Falling back to scanning...\n" unless $response =~ /^\{/;
119 return $json_pkg->new->utf8->decode($response);
122 sub is_work_tree_watched {
123 my ($output) = @_;
124 my $error = $output->{error};
125 if ($retry > 0 and $error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) {
126 $retry--;
127 my $response = qx/watchman watch "$git_work_tree"/;
128 die "Failed to make watchman watch '$git_work_tree'.\n" .
129 "Falling back to scanning...\n" if $? != 0;
130 $output = $json_pkg->new->utf8->decode($response);
131 $error = $output->{error};
132 die "Watchman: $error.\n" .
133 "Falling back to scanning...\n" if $error;
135 # Uncomment for debugging watchman output
136 # open (my $fh, ">", ".git/watchman-output.out");
137 # close $fh;
139 # Watchman will always return all files on the first query so
140 # return the fast "everything is dirty" flag to git and do the
141 # Watchman query just to get it over with now so we won't pay
142 # the cost in git to look up each individual file.
143 my $o = watchman_clock();
144 $error = $output->{error};
146 die "Watchman: $error.\n" .
147 "Falling back to scanning...\n" if $error;
149 output_result($o->{clock}, ("/"));
150 $last_update_token = $o->{clock};
152 eval { launch_watchman() };
153 return 0;
156 die "Watchman: $error.\n" .
157 "Falling back to scanning...\n" if $error;
159 return 1;
162 sub get_working_dir {
163 my $working_dir;
164 if ($^O =~ 'msys' || $^O =~ 'cygwin') {
165 $working_dir = Win32::GetCwd();
166 $working_dir =~ tr/\\/\//;
167 } else {
168 require Cwd;
169 $working_dir = Cwd::cwd();
172 return $working_dir;