stanwood/Stanwood_Debugger_iOS

#!/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 1) and a time in nanoseconds
# formatted as a string and outputs to stdout all files that have been
# modified since the given time. 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, $time) = @ARGV;

# Check the hook interface version

if ($version == 1) {
    # convert nanoseconds to seconds
    $time = int $time / 1000000000;
} else {
    die "Unsupported query-fsmonitor hook version '$version'.\n" .
        "Falling back to scanning...\n";
}

my $git_work_tree;
if ($^O =~ 'msys' || $^O =~ 'cygwin') {
    $git_work_tree = Win32::GetCwd();
    $git_work_tree =~ tr/\\/\//;
} else {
    require Cwd;
    $git_work_tree = Cwd::cwd();
}

my $retry = 1;

launch_watchman();

sub launch_watchman {

    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 $time but were not transient (ie created after
    # $time but no longer exist).
    #
    # 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.
    #
    # The category of transient files that we want to ignore will have a
    # creation clock (cclock) newer than $time_t value and will also not
    # currently exist.

    my $query = <<"    END";
        ["query", "$git_work_tree", {
            "since": $time,
            "fields": ["name"],
            "expression": ["not", ["allof", ["since", $time, "cclock"], ["not", "exists"]]]
        }]
    END

    print CHLD_IN $query;
    close CHLD_IN;
    my $response = do {local $/; <CHLD_OUT>};

    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 =~ /^\{/;

    my $json_pkg;
    eval {
        require JSON::XS;
        $json_pkg = "JSON::XS";
        1;
    } or do {
        require JSON::PP;
        $json_pkg = "JSON::PP";
    };

    my $o = $json_pkg->new->utf8->decode($response);

    if ($retry > 0 and $o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) {
        print STDERR "Adding '$git_work_tree' to watchman's watch list.\n";
        $retry--;
        qx/watchman watch "$git_work_tree"/;
        die "Failed to make watchman watch '$git_work_tree'.\n" .
            "Falling back to scanning...\n" if $? != 0;

        # 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.
        print "/\0";
        eval { launch_watchman() };
        exit 0;
    }

    die "Watchman: $o->{error}.\n" .
        "Falling back to scanning...\n" if $o->{error};

    binmode STDOUT, ":utf8";
    local $, = "\0";
    print @{$o->{files}};
}