t/t7519/fsmonitor-watchman

   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 1) and a time in nanoseconds
  12 # formatted as a string and outputs to stdout all files that have been
  13 # modified since the given time. Paths must be relative to the root of
  14 # 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, $time) = @ARGV;
  20 #print STDERR "$0 $version $time\n";
  21
  22 # Check the hook interface version
  23
  24 if ($version == 1) {
  25         # convert nanoseconds to seconds
  26         $time = int $time / 1000000000;
  27 } else {
  28         die "Unsupported query-fsmonitor hook version '$version'.\n" .
  29             "Falling back to scanning...\n";
  30 }
  31
  32 my $git_work_tree;
  33 if ($^O =~ 'msys' || $^O =~ 'cygwin') {
  34         $git_work_tree = Win32::GetCwd();
  35         $git_work_tree =~ tr/\\/\//;
  36 } else {
  37         require Cwd;
  38         $git_work_tree = Cwd::cwd();
  39 }
  40
  41 my $retry = 1;
  42
  43 launch_watchman();
  44
  45 sub launch_watchman {
  46
  47         my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j')
  48             or die "open2() failed: $!\n" .
  49             "Falling back to scanning...\n";
  50
  51         # In the query expression below we're asking for names of files that
  52         # changed since $time but were not transient (ie created after
  53         # $time but no longer exist).
  54         #
  55         # To accomplish this, we're using the "since" generator to use the
  56         # recency index to select candidate nodes and "fields" to limit the
  57         # output to file names only. Then we're using the "expression" term to
  58         # further constrain the results.
  59         #
  60         # The category of transient files that we want to ignore will have a
  61         # creation clock (cclock) newer than $time_t value and will also not
  62         # currently exist.
  63
  64         my $query = <<" END";
  65                 ["query", "$git_work_tree", {
  66                         "since": $time,
  67                         "fields": ["name"],
  68                         "expression": ["not", ["allof", ["since", $time, "cclock"], ["not", "exists"]]]
  69                 }]
  70         END
  71
  72         open (my $fh, ">", ".git/watchman-query.json");
  73         print $fh $query;
  74         close $fh;
  75
  76         print CHLD_IN $query;
  77         close CHLD_IN;
  78         my $response = do {local $/; <CHLD_OUT>};
  79
  80         open ($fh, ">", ".git/watchman-response.json");
  81         print $fh $response;
  82         close $fh;
  83
  84         die "Watchman: command returned no output.\n" .
  85             "Falling back to scanning...\n" if $response eq "";
  86         die "Watchman: command returned invalid output: $response\n" .
  87             "Falling back to scanning...\n" unless $response =~ /^\{/;
  88
  89         my $json_pkg;
  90         eval {
  91                 require JSON::XS;
  92                 $json_pkg = "JSON::XS";
  93                 1;
  94         } or do {
  95                 require JSON::PP;
  96                 $json_pkg = "JSON::PP";
  97         };
  98
  99         my $o = $json_pkg->new->utf8->decode($response);
 100
 101         if ($retry > 0 and $o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) {
 102                 print STDERR "Adding '$git_work_tree' to watchman's watch list.\n";
 103                 $retry--;
 104                 qx/watchman watch "$git_work_tree"/;
 105                 die "Failed to make watchman watch '$git_work_tree'.\n" .
 106                     "Falling back to scanning...\n" if $? != 0;
 107
 108                 # Watchman will always return all files on the first query so
 109                 # return the fast "everything is dirty" flag to git and do the
 110                 # Watchman query just to get it over with now so we won't pay
 111                 # the cost in git to look up each individual file.
 112
 113                 open ($fh, ">", ".git/watchman-output.out");
 114                 print "/\0";
 115                 close $fh;
 116
 117                 print "/\0";
 118                 eval { launch_watchman() };
 119                 exit 0;
 120         }
 121
 122         die "Watchman: $o->{error}.\n" .
 123             "Falling back to scanning...\n" if $o->{error};
 124
 125         open ($fh, ">", ".git/watchman-output.out");
 126         binmode $fh, ":utf8";
 127         print $fh @{$o->{files}};
 128         close $fh;
 129
 130         binmode STDOUT, ":utf8";
 131         local $, = "\0";
 132         print @{$o->{files}};
 133 }