Automatically change the Java version if needed

Manually-specified Java version still applies to:
- Minecraft versions below 1.17 (default is Java 8)
- Minecraft version 1.17.x (allow choosing between Java 16 and 17)

Natives/JavaGUIViewController.m

@@ -114,7 +114,7 @@ const void * _CGDataProviderGetBytePointerCallbackAWT(void *info) {
     rgbArray = calloc(4, (size_t) (savedWidth * savedHeight));
 
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-        launchJVM(@".LaunchJAR", self.filepath, savedWidth * resolutionScale, savedHeight * resolutionScale);
+        launchJVM(nil, self.filepath, savedWidth * resolutionScale, savedHeight * resolutionScale, 8);
     });
 }
 

Natives/JavaLauncher.h

@@ -17,4 +17,4 @@ typedef jint JLI_Launch_func(int argc, char ** argv, /* main argc, argc */
 );
 JLI_Launch_func *pJLI_Launch;
 
-int launchJVM(NSString *username, NSString *selectedVersion, int width, int height);
+int launchJVM(NSString *username, NSString *selectedVersion, int width, int height, int minVersion);

Natives/JavaLauncher.m

@@ -12,8 +12,9 @@
 
 #include "log.h"
 #include "utils.h"
-#include "JavaLauncher.h"
 
+#import "ios_uikit_bridge.h"
+#import "JavaLauncher.h"
 #import "LauncherPreferences.h"
 
 #define fm NSFileManager.defaultManager
@@ -59,56 +60,70 @@ void init_loadCustomJvmFlags() {
             margv[margc] = (char *) [[@"-" stringByAppendingString:jvmarg] UTF8String];
         }
 
-        NSLog(@"[Pre-init] Added custom JVM flag: %s", margv[margc]);
+        NSLog(@"[JavaLauncher] Added custom JVM flag: %s", margv[margc]);
         ++margc;
     }
 }
 
-NSString* environmentFailsafes() {
-    NSString *javaHome_pre;
-    if (strncmp(getenv("BUNDLE_PATH"), "/Applications", 13) == 0) {
-        if ([fm fileExistsAtPath:JRE8_HOME_JB]) {
-            javaHome_pre = JRE8_HOME_JB;
-        } else if ([fm fileExistsAtPath:JRE16_HOME_JB]) {
-            regLog("[Pre-init] Java 8 wasn't found on your device. Install Java 8 for more compatibility and the mod installer.");
-            javaHome_pre = JRE16_HOME_JB;
-        } else if ([fm fileExistsAtPath:JRE17_HOME_JB]) {
-            regLog("[Pre-init] Java 8 wasn't found on your device. Install Java 8 for more compatibility and the mod installer.");
-            javaHome_pre = JRE17_HOME_JB;
-        } else {
-            regLog("[Pre-init] FATAL ERROR: Java wasn't found on your device, PojavLauncher cannot continue, aborting.");
-            abort();
+NSString* environmentFailsafes(int minVersion) {
+    NSString *javaHome = nil;
+    if (getenv("POJAV_DETECTEDJB")) {
+        BOOL foundJava8 = [fm fileExistsAtPath:JRE8_HOME_JB];
+        if (!foundJava8) {
+            regLog("[JavaLauncher] Java 8 wasn't found on your device. Install Java 8 for more compatibility and the mod installer.");
         }
-    } else {
-        javaHome_pre = [NSString stringWithFormat:@"%s/jre", getenv("POJAV_HOME")];
+
+        if (foundJava8 && minVersion <= 8) {
+            javaHome = JRE8_HOME_JB;
+        } else if ([fm fileExistsAtPath:JRE16_HOME_JB] && minVersion <= 16) {
+            javaHome = JRE16_HOME_JB;
+        } else if ([fm fileExistsAtPath:JRE17_HOME_JB] && minVersion <= 17) {
+            javaHome = JRE17_HOME_JB;
+        }
+    } else if (minVersion <= 8) {
+        javaHome = [NSString stringWithFormat:@"%s/jre", getenv("POJAV_HOME")];
     }
 
-    javaHome = javaHome_pre.UTF8String;
-    setPreference(@"java_home", javaHome_pre);
-    return javaHome_pre;
+    if (javaHome == nil) {
+        showDialog(viewController, NSLocalizedString(@"Error", nil), [NSString stringWithFormat:@"Minecraft %@ requires Java %d in order to run. Please install it first.", getPreference(@"selected_version"), minVersion]);
+    }
+
+    return javaHome;
 }
 
-int launchJVM(NSString *username, NSString *selectedVersion, int width, int height) {
+int launchJVM(NSString *username, NSString *selectedVersion, int width, int height, int minVersion) {
     sprintf((char*) java_libs_path, "%s/libs", getenv("BUNDLE_PATH"));
 
-    regLog("[Pre-init] Beginning JVM launch\n");
+    regLog("[JavaLauncher] Beginning JVM launch\n");
 
     NSString *javaHome_pre = getPreference(@"java_home");
-    javaHome = javaHome_pre.UTF8String;
-    if (javaHome_pre.length == 0) {
-        environmentFailsafes();
-        regLog("[Pre-init] JAVA_HOME environment variable was not set. Defaulting to %s for future use.\n", javaHome);
-    } else {
+
+    // We handle unset JAVA_HOME right there
+    if (username == nil || getSelectedJavaVersion() < minVersion) {
+        javaHome_pre = environmentFailsafes(minVersion);
+        NSLog(@"[JavaLauncher] Changed to Java %d for the request", minVersion);
+    } /* else if (javaHome_pre.length == 0) {
+        javaHome_pre = environmentFailsafes(minVersion);
+        setPreference(@"java_home", javaHome_pre);
+        NSLog(@"[JavaLauncher] JAVA_HOME environment variable was not set. Default to %@ for future use.\n", javaHome_pre);
+    } */ else {
         if (![NSFileManager.defaultManager fileExistsAtPath:javaHome_pre]) {
-            regLog("[Pre-Init] Failed to locate %s. Restoring default value for JAVA_HOME.", javaHome);
-            environmentFailsafes();
+            javaHome_pre = environmentFailsafes(minVersion);
+            setPreference(@"java_home", javaHome_pre);
+            NSLog(@"[JavaLauncher] Failed to locate %@. Restored default value for JAVA_HOME.", javaHome_pre);
         } else {
-            regLog("[Pre-Init] Restored preference: JAVA_HOME is set to %s\n", javaHome);
+            NSLog(@"[JavaLauncher] Restored preference: JAVA_HOME is set to %@\n", javaHome_pre);
         }
     }
+
+    if (javaHome_pre == nil) {
+        return 1;
+    }
+
+    javaHome = javaHome_pre.UTF8String;
     setenv("JAVA_HOME", javaHome, 1);
 
-    if (strncmp(getenv("BUNDLE_PATH"), "/Applications", 13)) {
+    if (!getenv("POJAV_DETECTEDJB")) {
         char src[2048], dst[2048];
 
         // Symlink frameworks -> dylibs on jailed environment
@@ -200,9 +215,9 @@ int launchJVM(NSString *username, NSString *selectedVersion, int width, int heig
         renderer_pre = @"libgl4es_114.dylib";
         setPreference(@"renderer", renderer_pre);
         renderer = [renderer_pre cStringUsingEncoding:NSUTF8StringEncoding];
-        regLog("[Pre-init] RENDERER environment variable was not set. Defaulting to %s for future use.\n", renderer);
+        regLog("[JavaLauncher] RENDERER environment variable was not set. Defaulting to %s for future use.\n", renderer);
     } else {
-        regLog("[Pre-Init] Restored preference: RENDERER is set to %s\n", renderer);
+        regLog("[JavaLauncher] Restored preference: RENDERER is set to %s\n", renderer);
     }
     setenv("POJAV_RENDERER", renderer, 1);
     
@@ -230,7 +245,7 @@ int launchJVM(NSString *username, NSString *selectedVersion, int width, int heig
         classpath[cplen-1] = '\0';
         closedir(d);
     }
-    debugLog("[Pre-init] Classpath generated: %s", classpath);
+    debugLog("[JavaLauncher] Classpath generated: %s", classpath);
 
     // Check if JVM restarts
     char *frameworkPath, *javaPath, *jnaLibPath, *userDir, *userHome, *memMin, *memMax, *arcDNS;
@@ -242,7 +257,7 @@ int launchJVM(NSString *username, NSString *selectedVersion, int width, int heig
     asprintf(&memMin, "-Xms%sM", allocmem);
     asprintf(&memMax, "-Xmx%sM", allocmem);
     asprintf(&arcDNS, "-javaagent:%s/arc_dns_injector.jar=23.95.137.176", java_libs_path);
-    NSLog(@"[Pre-init] Java executable path: %s", javaPath);
+    NSLog(@"[JavaLauncher] Java executable path: %s", javaPath);
     setenv("JAVA_EXT_EXECNAME", javaPath, 1);
 
     margv[margc++] = javaPath;
@@ -315,7 +330,11 @@ int launchJVM(NSString *username, NSString *selectedVersion, int width, int heig
     margv[margc++] = classpath;
     margv[margc++] = "net.kdt.pojavlaunch.PLaunchApp";
 
-    margv[margc++] = (char *)username.UTF8String;
+    if (username == nil) {
+        margv[margc++] = ".LaunchJAR";
+    } else {
+        margv[margc++] = (char *)username.UTF8String;
+    }
     margv[margc++] = (char *)selectedVersion.UTF8String;
     margv[margc++] = (char *)[NSString stringWithFormat:@"%dx%d", width, height].UTF8String;
 

Natives/LauncherPreferences.h

@@ -7,5 +7,6 @@
 void loadPreferences();
 id getPreference(NSString* key);
 NSMutableDictionary* getDictionary(NSString *type);
+int getSelectedJavaVersion();
 void setDefaultValueForPref(NSMutableDictionary *dict, NSString* key, id value);
 void setPreference(NSString* key, id value);

Natives/LauncherPreferences.m

@@ -46,6 +46,21 @@ NSMutableDictionary *getDictionary(NSString *type) {
     return nil;
 }
 
+int getSelectedJavaVersion() {
+    NSString *java = [getPreference(@"java_home") lastPathComponent];
+    if (java.length == 0) {
+        return 0;
+    } else if ([java hasPrefix:@"java-"] && [java hasSuffix:@"-openjdk"]) {
+        return [java substringWithRange:NSMakeRange(5, java.length - 13)].intValue;
+    } else if ([java isEqualToString:@"jre"]) {
+        // TODO for jailbroken: jre8 and jre17
+        return 8;
+    } else {
+        NSLog(@"FIXME: What is the Java version of %@?", java);
+        return 0;
+    }
+}
+
 void setDefaultValueForPref(NSMutableDictionary *dict, NSString* key, id value) {
     if (!dict[key]) {
         dict[key] = value;

Natives/LauncherPreferencesViewController.m

@@ -272,12 +272,10 @@ int tempIndex;
 
     JRE8_HOME_SB = [NSString stringWithFormat:@"%s/jre8", getenv("POJAV_HOME")];
     if(getenv("POJAV_DETECTEDJB")) {
-        if ([getPreference(@"java_home") isEqualToString:JRE8_HOME_JB]) {
-            jhomeTextField.text = JRE8_NAME_JB;
-        } else if ([getPreference(@"java_home") isEqualToString:JRE16_HOME_JB]) {
-            jhomeTextField.text = JRE16_NAME_JB;
-        } else if ([getPreference(@"java_home") isEqualToString:JRE17_HOME_JB]) {
-            jhomeTextField.text = JRE17_NAME_JB;
+        switch (getSelectedJavaVersion()) {
+            case 8: jhomeTextField.text = JRE8_NAME_JB; break;
+            case 16: jhomeTextField.text = JRE16_NAME_JB; break;
+            case 17: jhomeTextField.text = JRE17_NAME_JB; break;
         }
     } else {
         jhomeTextField.text = JRE8_NAME_SB;

Natives/LauncherViewController.m

@@ -270,8 +270,9 @@ int versionSelectedAt = 0;
 
 - (void)enterModInstaller:(UIBarButtonItem*)sender {
     NSString *javaVer = getPreference(@"java_home");
-    if(![javaVer containsString:(@"java-8-openjdk")] && ![javaVer containsString:(@"jre8")]) {
-        UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Cannot use the mod installer" message:@"In order to use the mod installer, you need to install Java 8 and specify it in the Preferences menu." preferredStyle:UIAlertControllerStyleActionSheet];
+    NSFileManager *fileManager = [NSFileManager defaultManager];
+    if(![fileManager fileExistsAtPath:JRE8_HOME_JB] && !getenv("POJAV_DETECTEDJB")) {
+        UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Cannot use the mod installer" message:@"In order to use the mod installer, you need to install Java 8." preferredStyle:UIAlertControllerStyleActionSheet];
         if (alert.popoverPresentationController != nil) {
             alert.popoverPresentationController.sourceView = self.view;
             alert.popoverPresentationController.sourceRect = CGRectMake(self.view.frame.size.width-10.0, 0, 10, 10);

Natives/MinecraftDownloader.m

@@ -477,6 +477,7 @@ static AFURLSessionManager* manager;
             if (!success) return;
 
             isUseStackQueueCall = json[@"arguments"] != nil;
+            minJavaVersion = [json[@"javaVersion"][@"majorVersion"] intValue];
 
             dispatch_async(dispatch_get_main_queue(), ^{
                 callback(nil, mainProgress, nil);

Natives/SurfaceViewController.m

@@ -317,7 +317,7 @@ const void * _CGDataProviderGetBytePointerCallbackOSMESA(void *info) {
     // [self setPreferredFramesPerSecond:1000];
 
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-        launchJVM(BaseAuthenticator.current.authData[@"username"], getPreference(@"selected_version"), savedWidth * resolutionScale, savedHeight * resolutionScale);
+        launchJVM(BaseAuthenticator.current.authData[@"username"], getPreference(@"selected_version"), savedWidth * resolutionScale, savedHeight * resolutionScale, minJavaVersion);
     });
     //callback_SurfaceViewController_launchMinecraft(savedWidth * resolutionScale, savedHeight * resolutionScale);
 }

Natives/utils.h

@@ -36,32 +36,22 @@
 #define SPECIALBTN_SCROLLUP -7
 #define SPECIALBTN_SCROLLDOWN -8
 
-static float resolutionScale = 1.0;
-BOOL isControlModifiable;
-
+int minJavaVersion;
+JavaVM* runtimeJavaVMPtr;
+JNIEnv* runtimeJNIEnvPtr;
 UIViewController *viewController;
 
 void* gbuffer; // OSMesa framebuffer
-
-JavaVM* runtimeJavaVMPtr;
-JNIEnv* runtimeJNIEnvPtr;
-
-//JNIEnv* dalvikJNIEnvPtr_ANDROID;
-//JNIEnv* dalvikJNIEnvPtr_JRE;
-
 long showingWindow;
-
-bool isInputReady, isCursorEntered, isPrepareGrabPos, isUseStackQueueCall;
-
-jboolean isGrabbing;
-
 int savedWidth, savedHeight;
-
+bool isInputReady, isCursorEntered, isPrepareGrabPos, isUseStackQueueCall;
+jboolean isGrabbing;
 BOOL virtualMouseEnabled;
 
+static float resolutionScale = 1.0;
+BOOL isControlModifiable;
 
 // Init functions
-void init_hookCFRunLoop();
 void init_hookFunctions();