#!/usr/bin/env perl

# Copyright (C) 2014 Apple Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1.  Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer. 
# 2.  Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution. 
#
# THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

use strict;
use FindBin;
use Getopt::Long qw(:config pass_through);
use POSIX;

# We first want to run the test once to determine what the number of encountered
# checks is. Then we want to run it again some number of times with random check
# amounts. The test is successful if after printing a message that we're
# intending to throw the fuzz exception, it prints another message saying that it
# caught the exception.

my $repeat = 100;
my $seed = time();
my $verbose = 0;

# We allow flags to be passed via environment variables, which is rather useful for
# running with the run-jsc-stress-tests harness.
if (defined($ENV{JS_EFUZZ_REPEAT})) {
    $repeat = $ENV{JS_EFUZZ_REPEAT};
}
if (defined($ENV{JS_EFUZZ_SEED})) {
    $seed = $ENV{JS_EFUZZ_SEED};
}
if (defined($ENV{JS_EFUZZ_VERBOSE})) {
    $verbose = $ENV{JS_EFUZZ_VERBOSE};
}

GetOptions(
    'repeat=s' => \$repeat,
    'seed=s' => \$seed,
    'verbose' => \$verbose
);

my $commandString = shift @ARGV;

my $checkCount;

sub fail {
    my $context = shift;
    select((select(STDOUT), $ |= 1)[0]); # This is a perlism for flush. We need to do it this way to support older perls.
    select((select(STDERR), $ |= 1)[0]);
    die "Failure for command $commandString with seed $seed, repeat $repeat: $context";
}

if (shift @ARGV) {
    die "Ignoring garbage arguments; only the first non-option argument is used as the command string.";
}

open (my $testInput, "$commandString |") or fail("Cannot execute initial command when getting check count");
while (my $inputLine = <$testInput>) {
    chomp($inputLine);
    my $handled = 0;
    if ($inputLine =~ /^JSC EXCEPTION FUZZ:/) {
        if ($' =~ /encountered ([0-9]+) checks\./) {
            $checkCount = $1;
        }
        $handled = 1;
    }
    if (!$handled || $verbose) {
        print "checkCount: $inputLine\n";
    }
}
close($testInput);

if ($verbose) {
    print "Check count: $checkCount\n";
    print "Seed: $seed\n";
}

if (!$checkCount) {
    print "Exception fuzz testing not supported by jsc binary.\n";
    exit 0;
}

srand($seed);

for (my $iteration = 0; $iteration < $repeat; ++$iteration) {
    my $target = int(rand() * ($checkCount - 1)) + 2;
    if ($verbose) {
        print "iteration($iteration) target($target): Running.\n";
    }
    open ($testInput, "$commandString --fireExceptionFuzzAt=$target |") or fail("Cannot execute command on iteration $iteration");
    my $state = "waiting";
    while (my $inputLine = <$testInput>) {
        chomp($inputLine);
        my $handled = 0;
        if ($inputLine =~ /^JSC EXCEPTION FUZZ:/) {
            if ($' =~ /Throwing fuzz exception/) {
                if ($verbose) {
                    print "iteration($iteration) target($target): Threw fuzz exception.\n";
                }
                if ($state eq "waiting") {
                    $state = "thrown";
                } else {
                    fail("Unexpected $inputLine while in state $state for target $target");
                }
            } elsif ($' =~ /Caught exception/) {
                if ($verbose) {
                    print "iteration($iteration) target($target): Caught fuzz exception.\n";
                }
                if ($state eq "thrown") {
                    $state = "waiting";
                } else {
                    fail("Unexpected $inputLine while in state $state for target $target");
                }
            }
            $handled = 1;
        }
        if (!$handled || $verbose) {
            print "iteration($iteration) target($target): $inputLine\n";
        }
    }
    if ($state ne "waiting") {
        fail("Unexpected state $state at end for target $target");
    }
    close($testInput);
    if ($? != 0) {
        fail("Unexpected exit status $? for target $target");
    }
}

if ($verbose) {
    print "Success!\n";
}