Added tool to dump JSON contents of encoded crashdump data

tools/decode-crashdump.php

@@ -0,0 +1,87 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+ */
+
+declare(strict_types=1);
+
+namespace pocketmine\tools\decode_crashdump;
+
+use function array_pop;
+use function array_slice;
+use function base64_decode;
+use function count;
+use function file;
+use function file_put_contents;
+use function fwrite;
+use function implode;
+use function json_decode;
+use function json_encode;
+use function realpath;
+use function trim;
+use function zlib_decode;
+use const FILE_IGNORE_NEW_LINES;
+use const PHP_EOL;
+use const STDERR;
+
+if(count($argv) === 2){
+	$input = $argv[1];
+	$output = "decoded.json";
+}elseif(count($argv) === 3){
+	[, $input, $output] = $argv;
+}else{
+	fwrite(STDERR, "Required arguments: input file, output file" . PHP_EOL);
+	exit(1);
+}
+
+$lines = file($input, FILE_IGNORE_NEW_LINES);
+if($lines === false){
+	fwrite(STDERR, "Unable to read file $input" . PHP_EOL);
+	exit(1);
+}
+
+$start = -1;
+foreach($lines as $num => $line){
+	if(trim($line) === "===BEGIN CRASH DUMP==="){
+		$start = $num + 1;
+		break;
+	}
+}
+
+if($start === -1){
+	fwrite(STDERR, "Crashdump encoded data not found in target file" . PHP_EOL);
+	exit(1);
+}
+
+$data = array_slice($lines, $start);
+array_pop($data);
+
+$zlibData = base64_decode(implode("", $data), true);
+if($zlibData === false){
+	fwrite(STDERR, "Invalid encoded data in crashdump" . PHP_EOL);
+	exit(1);
+}
+$decoded = zlib_decode($zlibData);
+if($decoded === false){
+	fwrite(STDERR, "Invalid compressed data in crashdump" . PHP_EOL);
+	exit(1);
+}
+
+file_put_contents($output, json_encode(json_decode($decoded), JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
+echo "Wrote decoded crashdump to " . realpath($output) . PHP_EOL;