build_scripts/.git/hooks/fsmonitor-watchman.sample

go back
1 | #!/usr/bin/perl
2 |
3 | use strict;
4 | use warnings;
5 | use IPC::Open2;
6 |
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.
10 | #
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.
15 | #
16 | # To enable this hook, rename this file to "query-watchman" and set
17 | # 'git config core.fsmonitor .git/hooks/query-watchman'
18 | #
19 | my ($version, $last_update_token) = @ARGV;
20 |
21 | # Uncomment for debugging
22 | # print STDERR "$0 $version $last_update_token\n";
23 |
24 | # Check the hook interface version
25 | if ($version ne 2) {
26 | die "Unsupported query-fsmonitor hook version '$version'.\n" .
27 | "Falling back to scanning...\n";
28 | }
29 |
30 | my $git_work_tree = get_working_dir();
31 |
32 | my $retry = 1;
33 |
34 | my $json_pkg;
35 | eval {
36 | require JSON::XS;
37 | $json_pkg = "JSON::XS";
38 | 1;
39 | } or do {
40 | require JSON::PP;
41 | $json_pkg = "JSON::PP";
42 | };
43 |
44 | launch_watchman();
45 |
46 | sub launch_watchman {
47 | my $o = watchman_query();
48 | if (is_work_tree_watched($o)) {
49 | output_result($o->{clock}, @{$o->{files}});
50 | }
51 | }
52 |
53 | sub output_result {
54 | my ($clockid, @files) = @_;
55 |
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;
61 |
62 | binmode STDOUT, ":utf8";
63 | print $clockid;
64 | print "\0";
65 | local $, = "\0";
66 | print @files;
67 | }
68 |
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;
73 |
74 | return $json_pkg->new->utf8->decode($response);
75 | }
76 |
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";
81 |
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.
84 | #
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 | my $last_update_line = "";
90 | if (substr($last_update_token, 0, 1) eq "c") {
91 | $last_update_token = "\"$last_update_token\"";
92 | $last_update_line = qq[\n"since": $last_update_token,];
93 | }
94 | my $query = <<" END";
95 | ["query", "$git_work_tree", {$last_update_line
96 | "fields": ["name"],
97 | "expression": ["not", ["dirname", ".git"]]
98 | }]
99 | END
100 |
101 | # Uncomment for debugging the watchman query
102 | # open (my $fh, ">", ".git/watchman-query.json");
103 | # print $fh $query;
104 | # close $fh;
105 |
106 | print CHLD_IN $query;
107 | close CHLD_IN;
108 | my $response = do {local $/; <CHLD_OUT>};
109 |
110 | # Uncomment for debugging the watch response
111 | # open ($fh, ">", ".git/watchman-response.json");
112 | # print $fh $response;
113 | # close $fh;
114 |
115 | die "Watchman: command returned no output.\n" .
116 | "Falling back to scanning...\n" if $response eq "";
117 | die "Watchman: command returned invalid output: $response\n" .
118 | "Falling back to scanning...\n" unless $response =~ /^\{/;
119 |
120 | return $json_pkg->new->utf8->decode($response);
121 | }
122 |
123 | sub is_work_tree_watched {
124 | my ($output) = @_;
125 | my $error = $output->{error};
126 | if ($retry > 0 and $error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) {
127 | $retry--;
128 | my $response = qx/watchman watch "$git_work_tree"/;
129 | die "Failed to make watchman watch '$git_work_tree'.\n" .
130 | "Falling back to scanning...\n" if $? != 0;
131 | $output = $json_pkg->new->utf8->decode($response);
132 | $error = $output->{error};
133 | die "Watchman: $error.\n" .
134 | "Falling back to scanning...\n" if $error;
135 |
136 | # Uncomment for debugging watchman output
137 | # open (my $fh, ">", ".git/watchman-output.out");
138 | # close $fh;
139 |
140 | # Watchman will always return all files on the first query so
141 | # return the fast "everything is dirty" flag to git and do the
142 | # Watchman query just to get it over with now so we won't pay
143 | # the cost in git to look up each individual file.
144 | my $o = watchman_clock();
145 | $error = $output->{error};
146 |
147 | die "Watchman: $error.\n" .
148 | "Falling back to scanning...\n" if $error;
149 |
150 | output_result($o->{clock}, ("/"));
151 | $last_update_token = $o->{clock};
152 |
153 | eval { launch_watchman() };
154 | return 0;
155 | }
156 |
157 | die "Watchman: $error.\n" .
158 | "Falling back to scanning...\n" if $error;
159 |
160 | return 1;
161 | }
162 |
163 | sub get_working_dir {
164 | my $working_dir;
165 | if ($^O =~ 'msys' || $^O =~ 'cygwin') {
166 | $working_dir = Win32::GetCwd();
167 | $working_dir =~ tr/\\/\//;
168 | } else {
169 | require Cwd;
170 | $working_dir = Cwd::cwd();
171 | }
172 |
173 | return $working_dir;
174 | }