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Diffstat (limited to 'build/shell/git_template/hooks/fsmonitor-watchman.sample')
| -rw-r--r-- | build/shell/git_template/hooks/fsmonitor-watchman.sample | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/build/shell/git_template/hooks/fsmonitor-watchman.sample b/build/shell/git_template/hooks/fsmonitor-watchman.sample new file mode 100644 index 0000000..367d462 --- /dev/null +++ b/build/shell/git_template/hooks/fsmonitor-watchman.sample @@ -0,0 +1,174 @@ +#!/usr/bin/env 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; +} |