Extract parsing command line file to a separate class + add unit tests

platform/android/java/lib/build.gradle

@@ -11,6 +11,8 @@ apply from: "../scripts/publish-module.gradle"
 
 dependencies {
     implementation "androidx.fragment:fragment:$versions.fragmentVersion"
+
+    testImplementation "junit:junit:4.13.2"
 }
 
 def pathToRootDir = "../../../../"
@@ -74,6 +76,7 @@ android {
         main {
             manifest.srcFile 'AndroidManifest.xml'
             java.srcDirs = ['src']
+            test.java.srcDirs = ['srcTest/java']
             res.srcDirs = ['res']
             aidl.srcDirs = ['aidl']
             assets.srcDirs = ['assets']

platform/android/java/lib/src/org/godotengine/godot/Godot.kt

@@ -56,6 +56,7 @@ import org.godotengine.godot.io.directory.DirectoryAccessHandler
 import org.godotengine.godot.io.file.FileAccessHandler
 import org.godotengine.godot.plugin.GodotPluginRegistry
 import org.godotengine.godot.tts.GodotTTS
+import org.godotengine.godot.utils.CommandLineFileParser
 import org.godotengine.godot.utils.GodotNetUtils
 import org.godotengine.godot.utils.PermissionsUtil
 import org.godotengine.godot.utils.PermissionsUtil.requestPermission
@@ -68,7 +69,7 @@ import org.godotengine.godot.xr.XRMode
 import java.io.File
 import java.io.FileInputStream
 import java.io.InputStream
-import java.nio.charset.StandardCharsets
+import java.lang.Exception
 import java.security.MessageDigest
 import java.util.*
 
@@ -120,6 +121,7 @@ class Godot(private val context: Context) : SensorEventListener {
 	val directoryAccessHandler = DirectoryAccessHandler(context)
 	val fileAccessHandler = FileAccessHandler(context)
 	val netUtils = GodotNetUtils(context)
+	private val commandLineFileParser = CommandLineFileParser()
 
 	/**
 	 * Tracks whether [onCreate] was completed successfully.
@@ -908,47 +910,18 @@ class Godot(private val context: Context) : SensorEventListener {
 	}
 
 	private fun getCommandLine(): MutableList<String> {
-		val original: MutableList<String> = parseCommandLine()
+		val commandLine = try {
+			commandLineFileParser.parseCommandLine(requireActivity().assets.open("_cl_"))
+		} catch (ignored: Exception) {
+			mutableListOf()
+		}
+
 		val hostCommandLine = primaryHost?.commandLine
 		if (!hostCommandLine.isNullOrEmpty()) {
-			original.addAll(hostCommandLine)
+			commandLine.addAll(hostCommandLine)
 		}
-		return original
-	}
 
-	private fun parseCommandLine(): MutableList<String> {
-		val inputStream: InputStream
-		return try {
-			inputStream = requireActivity().assets.open("_cl_")
-			val len = ByteArray(4)
-			var r = inputStream.read(len)
-			if (r < 4) {
-				return mutableListOf()
-			}
-			val argc =
-				(len[3].toInt() and 0xFF) shl 24 or ((len[2].toInt() and 0xFF) shl 16) or ((len[1].toInt() and 0xFF) shl 8) or (len[0].toInt() and 0xFF)
-			val cmdline = ArrayList<String>(argc)
-			for (i in 0 until argc) {
-				r = inputStream.read(len)
-				if (r < 4) {
-					return mutableListOf()
-				}
-				val strlen =
-					(len[3].toInt() and 0xFF) shl 24 or ((len[2].toInt() and 0xFF) shl 16) or ((len[1].toInt() and 0xFF) shl 8) or (len[0].toInt() and 0xFF)
-				if (strlen > 65535) {
-					return mutableListOf()
-				}
-				val arg = ByteArray(strlen)
-				r = inputStream.read(arg)
-				if (r == strlen) {
-					cmdline.add(String(arg, StandardCharsets.UTF_8))
-				}
-			}
-			cmdline
-		} catch (e: Exception) {
-			// The _cl_ file can be missing with no adverse effect
-			mutableListOf()
-		}
+		return commandLine
 	}
 
 	/**

platform/android/java/lib/src/org/godotengine/godot/utils/CommandLineFileParser.kt

@@ -0,0 +1,83 @@
+/**************************************************************************/
+/*  CommandLineFileParser.kt                                              */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+package org.godotengine.godot.utils
+
+import java.io.InputStream
+import java.nio.charset.StandardCharsets
+import java.util.ArrayList
+
+/**
+ * A class that parses the content of file storing command line params. Usually, this file is saved
+ * in `assets/_cl_` on exporting an apk
+ *
+ * Returns a mutable list of command lines
+ */
+internal class CommandLineFileParser {
+	fun parseCommandLine(inputStream: InputStream): MutableList<String> {
+		return try {
+			val headerBytes = ByteArray(4)
+			var argBytes = inputStream.read(headerBytes)
+			if (argBytes < 4) {
+				return mutableListOf()
+			}
+			val argc = decodeHeaderIntValue(headerBytes)
+
+			val cmdline = ArrayList<String>(argc)
+			for (i in 0 until argc) {
+				argBytes = inputStream.read(headerBytes)
+				if (argBytes < 4) {
+					return mutableListOf()
+				}
+				val strlen = decodeHeaderIntValue(headerBytes)
+
+				if (strlen > 65535) {
+					return mutableListOf()
+				}
+
+				val arg = ByteArray(strlen)
+				argBytes = inputStream.read(arg)
+				if (argBytes == strlen) {
+					cmdline.add(String(arg, StandardCharsets.UTF_8))
+				}
+			}
+			cmdline
+		} catch (e: Exception) {
+			// The _cl_ file can be missing with no adverse effect
+			mutableListOf()
+		}
+	}
+
+	private fun decodeHeaderIntValue(headerBytes: ByteArray): Int =
+		(headerBytes[3].toInt() and 0xFF) shl 24 or
+		((headerBytes[2].toInt() and 0xFF) shl 16) or
+		((headerBytes[1].toInt() and 0xFF) shl 8) or
+		(headerBytes[0].toInt() and 0xFF)
+}

platform/android/java/lib/srcTest/java/org/godotengine/godot/utils/CommandLineFileParserTest.kt

@@ -0,0 +1,104 @@
+/**************************************************************************/
+/*  CommandLineFileParserTest.kt                                          */
+/**************************************************************************/
+/*                         This file is part of:                          */
+/*                             GODOT ENGINE                               */
+/*                        https://godotengine.org                         */
+/**************************************************************************/
+/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
+/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+package org.godotengine.godot.utils
+
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.Parameterized
+import java.io.ByteArrayInputStream
+import java.io.InputStream
+
+// Godot saves command line params in the `assets/_cl_` file on exporting an apk.  By default,
+// without any other commands specified in `command_line/extra_args` in Export window, the content
+// of that _cl_ file consists of only the `--xr_mode_regular` and `--use_immersive` flags.
+// The `CL_` prefix here refers to that file
+private val CL_DEFAULT_NO_EXTRA_ARGS = byteArrayOf(2, 0, 0, 0, 17, 0, 0, 0, 45, 45, 120, 114, 95, 109, 111, 100, 101, 95, 114, 101, 103, 117, 108, 97, 114, 15, 0, 0, 0, 45, 45, 117, 115, 101, 95, 105, 109, 109, 101, 114, 115, 105, 118, 101)
+private val CL_ONE_EXTRA_ARG = byteArrayOf(3, 0, 0, 0, 15, 0, 0, 0, 45, 45, 117, 110, 105, 116, 95, 116, 101, 115, 116, 95, 97, 114, 103, 17, 0, 0, 0, 45, 45, 120, 114, 95, 109, 111, 100, 101, 95, 114, 101, 103, 117, 108, 97, 114, 15, 0, 0, 0, 45, 45, 117, 115, 101, 95, 105, 109, 109, 101, 114, 115, 105, 118, 101)
+private val CL_TWO_EXTRA_ARGS = byteArrayOf(4, 0, 0, 0, 16, 0, 0, 0, 45, 45, 117, 110, 105, 116, 95, 116, 101, 115, 116, 95, 97, 114, 103, 49, 16, 0, 0, 0, 45, 45, 117, 110, 105, 116, 95, 116, 101, 115, 116, 95, 97, 114, 103, 50, 17, 0, 0, 0, 45, 45, 120, 114, 95, 109, 111, 100, 101, 95, 114, 101, 103, 117, 108, 97, 114, 15, 0, 0, 0, 45, 45, 117, 115, 101, 95, 105, 109, 109, 101, 114, 115, 105, 118, 101)
+private val CL_EMPTY = byteArrayOf()
+private val CL_HEADER_TOO_SHORT = byteArrayOf(0, 0, 0)
+private val CL_INCOMPLETE_FIRST_ARG = byteArrayOf(2, 0, 0, 0, 17, 0, 0)
+private val CL_LENGTH_TOO_LONG_IN_FIRST_ARG = byteArrayOf(2, 0, 0, 0, 17, 0, 0, 45, 45, 120, 114, 95, 109, 111, 100, 101, 95, 114, 101, 103, 117, 108, 97, 114, 15, 0, 0, 0, 45, 45, 117, 115, 101, 95, 105, 109, 109, 101, 114, 115, 105, 118, 101)
+private val CL_MISMATCHED_ARG_LENGTH_AND_HEADER_ONE_ARG = byteArrayOf(2, 0, 0, 0, 10, 0, 0, 0, 45, 45, 120, 114)
+private val CL_MISMATCHED_ARG_LENGTH_AND_HEADER_IN_FIRST_ARG = byteArrayOf(2, 0, 0, 0, 17, 0, 0, 0, 45, 45, 120, 114, 95, 109, 111, 100, 101, 95, 114, 101, 103, 117, 108, 97, 15, 0, 0, 0, 45, 45, 117, 115, 101, 95, 105, 109, 109, 101, 114, 115, 105, 118, 101)
+
+@RunWith(Parameterized::class)
+class CommandLineFileParserTest(
+	private val inputStreamArg: InputStream,
+	private val expectedResult: List<String>,
+) {
+
+	private val commandLineFileParser = CommandLineFileParser()
+
+	companion object {
+		@JvmStatic
+		@Parameterized.Parameters
+		fun data() = listOf(
+			arrayOf(ByteArrayInputStream(CL_EMPTY), listOf<String>()),
+			arrayOf(ByteArrayInputStream(CL_HEADER_TOO_SHORT), listOf<String>()),
+
+			arrayOf(ByteArrayInputStream(CL_DEFAULT_NO_EXTRA_ARGS), listOf(
+				"--xr_mode_regular",
+				"--use_immersive",
+			)),
+
+			arrayOf(ByteArrayInputStream(CL_ONE_EXTRA_ARG), listOf(
+				"--unit_test_arg",
+				"--xr_mode_regular",
+				"--use_immersive",
+			)),
+
+			arrayOf(ByteArrayInputStream(CL_TWO_EXTRA_ARGS), listOf(
+				"--unit_test_arg1",
+				"--unit_test_arg2",
+				"--xr_mode_regular",
+				"--use_immersive",
+			)),
+
+			arrayOf(ByteArrayInputStream(CL_INCOMPLETE_FIRST_ARG), listOf<String>()),
+			arrayOf(ByteArrayInputStream(CL_LENGTH_TOO_LONG_IN_FIRST_ARG), listOf<String>()),
+			arrayOf(ByteArrayInputStream(CL_MISMATCHED_ARG_LENGTH_AND_HEADER_ONE_ARG), listOf<String>()),
+			arrayOf(ByteArrayInputStream(CL_MISMATCHED_ARG_LENGTH_AND_HEADER_IN_FIRST_ARG), listOf<String>()),
+		)
+	}
+
+	@Test
+	fun `Given inputStream, When parsing command line, Then a correct list is returned`() {
+		// given
+		val inputStream = inputStreamArg
+
+		// when
+		val result = commandLineFileParser.parseCommandLine(inputStream)
+
+		// then
+		assert(result == expectedResult) { "Expected: $expectedResult Actual: $result" }
+	}
+}