From 66c0ee00b80ed1b80580f5e23a04d71e5dfeb4ea Mon Sep 17 00:00:00 2001
From: E3FxGaming <8276268+E3FxGaming@users.noreply.github.com>
Date: Mon, 5 Apr 2021 16:37:29 +0200
Subject: [PATCH] Fix for the multi-sources not being generated properly
 (#6430)

* Potential fix for the multi-sources not being generated properly

As described here https://www.infoworld.com/article/2071275/when-runtime-exec---won-t.html under "Listing 4.2 BadExecJavac2.java" the limited buffer size of the standard input associated with the sub-process can cause problems with the Runtime exec method.

Consuming what the sub-process outputs should in theory allow for the process to finish (+ if you enable log level debug we could get some nice debug information in the future).

I've tested this on my local machine and it works there, please do not accept the PR with this commit before the Github checks pass successfully and I've looked further into this.

* Multi-sources not being generated properly - ErrorStream redirect

Now redirecting the errorStream of the sub-process to the standard output of the subprocess, so that we can consume it with the `javaProcess.inputStream` stream.
---
 multisrc/build.gradle.kts | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/multisrc/build.gradle.kts b/multisrc/build.gradle.kts
index c6253bc21..12cbc3004 100644
--- a/multisrc/build.gradle.kts
+++ b/multisrc/build.gradle.kts
@@ -1,3 +1,6 @@
+import java.io.BufferedReader
+import java.io.InputStreamReader
+
 plugins {
     id("com.android.library")
     kotlin("android")
@@ -24,22 +27,37 @@ tasks {
     val generateExtensions by registering {
         doLast {
             val isWindows = System.getProperty("os.name").toString().toLowerCase().contains("win")
-            val classPath = (configurations.debugCompileOnly.get().asFileTree.toList() +
+            var classPath = (configurations.debugCompileOnly.get().asFileTree.toList() +
                 listOf(
                     configurations.androidApis.get().asFileTree.first().absolutePath, // android.jar path
                     "$projectDir/build/intermediates/aar_main_jar/debug/classes.jar" // jar made from this module
                 ))
                 .joinToString(if (isWindows) ";" else ":")
-            val javaPath = "${System.getProperty("java.home")}/bin/java"
+
+            var javaPath = "${System.getProperty("java.home")}/bin/java"
 
             val mainClass = "generator.GeneratorMainKt" // Main class we want to execute
 
-            val javaCommand = if (isWindows) {
-                "\"$javaPath\" -classpath $classPath $mainClass".replace("/", "\\")
-            } else {
-                "$javaPath -classpath $classPath $mainClass"
+            if (isWindows) {
+                classPath = classPath.replace("/", "\\")
+                javaPath = javaPath.replace("/", "\\")
             }
-            val javaProcess = Runtime.getRuntime().exec(javaCommand)
+
+            val javaProcess = ProcessBuilder()
+                .directory(null).command(javaPath, "-classpath", classPath, mainClass)
+                .redirectErrorStream(true).start()
+
+            val inputStreamReader = InputStreamReader(javaProcess.inputStream)
+            val bufferedReader = BufferedReader(inputStreamReader)
+
+            var s: String?
+            while (bufferedReader.readLine().also { s = it } != null) {
+                logger.info(s)
+            }
+
+            bufferedReader.close()
+            inputStreamReader.close()
+
             val exitCode = javaProcess.waitFor()
             if (exitCode != 0) {
                 throw Exception("Java process failed with exit code: $exitCode")