/*

    File:       simple.c

    Description:    Sample code showing how to spin a new thread off to start the JVM

                        while using the primordial thread to run the AppKits main runloop.

    Copyright:  © Copyright 2003 Apple Computer, Inc. All rights reserved.

    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.

                ("Apple") in consideration of your agreement to the following terms, and your

                use, installation, modification or redistribution of this Apple software

                constitutes acceptance of these terms.  If you do not agree with these terms,

                please do not use, install, modify or redistribute this Apple software.

                In consideration of your agreement to abide by the following terms, and subject

                to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs

                copyrights in this original Apple software (the "Apple Software"), to use,

                reproduce, modify and redistribute the Apple Software, with or without

                modifications, in source and/or binary forms; provided that if you redistribute

                the Apple Software in its entirety and without modifications, you must retain

                this notice and the following text and disclaimers in all such redistributions of

                the Apple Software.  Neither the name, trademarks, service marks or logos of

                Apple Computer, Inc. may be used to endorse or promote products derived from the

                Apple Software without specific prior written permission from Apple.  Except as

                expressly stated in this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any patent rights that

                may be infringed by your derivative works or by other works in which the Apple

                Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

                WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

                WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR

                PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

                COMBINATION WITH YOUR PRODUCTS.

                IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

                CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

                GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

                ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION

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*/

#include <sys/stat.h>

#include <sys/resource.h>

#include <pthread.h>

#include <CoreFoundation/CoreFoundation.h>

#include "utils.h"

/*Starts a JVM using the options,classpath,main class, and args stored in a VMLauchOptions structure */ 

static void* startupJava(void *options) {    

    int result = 0;

    JNIEnv* env;

    JavaVM* theVM;

    VMLaunchOptions * launchOptions = (VMLaunchOptions*)options;

    /* default vm args */

    JavaVMInitArgs  vm_args;

/*

To invoke Java 1.4.1 or the currently preferred JDK as defined by the operating system (1.4.2 as of the release of this sample and the release of Mac OS X 10.4) nothing changes in 10.4 vs 10.3 in that when a JNI_VERSION_1_4 is passed into JNI_CreateJavaVM as the vm_args.version it returns the current preferred JDK.

To specify the current preferred JDK in a family of JVM's, say the 1.5.x family, applications should set the environment variable JAVA_JVM_VERSION to 1.5, and then pass JNI_VERSION_1_4 into JNI_CreateJavaVM as the vm_args.version. To get a specific Java 1.5 JVM, say Java 1.5.0, set the environment variable JAVA_JVM_VERSION to 1.5.0. For Java 1.6 it will be the same in that applications will need to set the environment variable JAVA_JVM_VERSION to 1.6 to specify the current preferred 1.6 Java VM, and to get a specific Java 1.6 JVM, say Java 1.6.1, set the environment variable JAVA_JVM_VERSION to 1.6.1.

To make this sample bring up the current preferred 1.5 JVM, set the environment variable JAVA_JVM_VERSION to 1.5 before calling JNI_CreateJavaVM as shown below.  Applications must currently check for availability of JDK 1.5 before requesting it.  If your application requires JDK 1.5 and it is not found, it is your responsibility to report an error to the user. To verify if a JVM is installed, check to see if the symlink, or directory exists for the JVM in /System/Library/Frameworks/JavaVM.framework/Versions/ before setting the environment variable JAVA_JVM_VERSION.

If the environment variable JAVA_JVM_VERSION is not set, and JNI_VERSION_1_4 is passed into JNI_CreateJavaVM as the vm_args.version, JNI_CreateJavaVM will return the current preferred JDK. Java 1.4.2 is the preferred JDK as of the release of this sample and the release of Mac OS X 10.4.

*/

    {

        CFStringRef targetJVM = CFSTR("1.5");

        CFBundleRef JavaVMBundle;

        CFURLRef    JavaVMBundleURL;

        CFURLRef    JavaVMBundlerVersionsDirURL;

        CFURLRef    TargetJavaVM;

        UInt8 pathToTargetJVM [PATH_MAX] = "\0";

        struct stat sbuf;

        // Look for the JavaVM bundle using its identifier

        JavaVMBundle = CFBundleGetBundleWithIdentifier(CFSTR("com.apple.JavaVM") );

        if(JavaVMBundle != NULL) {

            // Get a path for the JavaVM bundle

            JavaVMBundleURL = CFBundleCopyBundleURL(JavaVMBundle);

            CFRelease(JavaVMBundle);

            if(JavaVMBundleURL != NULL) {

                // Append to the path the Versions Component

                JavaVMBundlerVersionsDirURL = CFURLCreateCopyAppendingPathComponent(kCFAllocatorDefault,JavaVMBundleURL,CFSTR("Versions"),true);

                CFRelease(JavaVMBundleURL);

                if(JavaVMBundlerVersionsDirURL != NULL) {

                    // Append to the path the target JVM's Version

                    TargetJavaVM = CFURLCreateCopyAppendingPathComponent(kCFAllocatorDefault,JavaVMBundlerVersionsDirURL,targetJVM,true);

                    CFRelease(JavaVMBundlerVersionsDirURL);

                    if(TargetJavaVM != NULL) {

                        if(CFURLGetFileSystemRepresentation (TargetJavaVM,true,pathToTargetJVM,PATH_MAX )) {

                            // Check to see if the directory, or a sym link for the target JVM directory exists, and if so set the

                            // environment variable JAVA_JVM_VERSION to the target JVM.

                            if(stat((char*)pathToTargetJVM,&sbuf) == 0) {

                                // Ok, the directory exists, so now we need to set the environment var JAVA_JVM_VERSION to the CFSTR targetJVM

                                // We can reuse the pathToTargetJVM buffer to set the environement var.

                                if(CFStringGetCString(targetJVM,(char*)pathToTargetJVM,PATH_MAX,kCFStringEncodingUTF8))

                                    setenv("JAVA_JVM_VERSION", (char*)pathToTargetJVM,1);

                            }

                        }

                    CFRelease(TargetJavaVM);

                    }

                }

            }

        }

    }

    /* JNI_VERSION_1_4 is used on Mac OS X to indicate the 1.4.x and later JVM's */

    vm_args.version = JNI_VERSION_1_4;

    vm_args.options = launchOptions->options;

    vm_args.nOptions = launchOptions->nOptions;

    vm_args.ignoreUnrecognized  = JNI_TRUE;

    /* start a VM session */    

    result = JNI_CreateJavaVM(&theVM, (void**)&env, &vm_args);

    if ( result != 0 ) {

        fprintf(stderr, "[JavaAppLauncher Error] Error starting up VM.\n");

        exit(result);

        return NULL;

    }

    /* Find the main class */

    jclass mainClass = (*env)->FindClass(env, launchOptions->mainClass);

    if ( mainClass == NULL ) {

        (*env)->ExceptionDescribe(env);

        result = -1;

        goto leave;

    }

    /* Get the application's main method */

    jmethodID mainID = (*env)->GetStaticMethodID(env, mainClass, "main",

                                                 "([Ljava/lang/String;)V");

    if (mainID == NULL) {

        if ((*env)->ExceptionOccurred(env)) {

            (*env)->ExceptionDescribe(env);

        } else {

            fprintf(stderr, "[JavaAppLauncher Error] No main method found in specified class.\n");

        }

        result = -1;

        goto leave;

    }

    /* Build argument array */

    jobjectArray mainArgs = NewPlatformStringArray(env, (char **)launchOptions->args, launchOptions->numberOfArgs);

    if (mainArgs == nil) {

        (*env)->ExceptionDescribe(env);

        goto leave;

    }

    /* or create an empty array of java.lang.Strings to pass in as arguments to the main method

    jobjectArray mainArgs = (*env)->NewObjectArray(env, 0, 

                        (*env)->FindClass(env, "java/lang/String"), NULL);

    if (mainArgs == 0) {

        result = -1;

        goto leave;

    }

    */

    /* Invoke main method passing in the argument object. */

    (*env)->CallStaticVoidMethod(env, mainClass, mainID, mainArgs);

    if ((*env)->ExceptionOccurred(env)) {

        (*env)->ExceptionDescribe(env);

        result = -1;

        goto leave;

    }

leave:

    freeVMLaunchOptions(launchOptions);

    (*theVM)->DestroyJavaVM(theVM);

    exit(result);

    return NULL;

}

/* call back for dummy source used to make sure the CFRunLoop doesn't exit right away */

/* This callback is called when the source has fired. */

void sourceCallBack (  void *info  ) {}

/*  The following code will spin a new thread off to start the JVM

    while using the primordial thread to run the main runloop.

*/

int main(int argc, const char **argv)

{

    CFRunLoopSourceContext sourceContext;

    /* Start the thread that runs the VM. */

    pthread_t vmthread;

    /* Parse the args */

    VMLaunchOptions * launchOptions = NewVMLaunchOptions(argc, argv);

    /* Set our name for the Application Menu to our Main class */

    setAppName(launchOptions->mainClass);

    /* create a new pthread copying the stack size of the primordial pthread */ 

    struct rlimit limit;

    size_t stack_size = 0;

    int rc = getrlimit(RLIMIT_STACK, &limit);

    if (rc == 0) {

        if (limit.rlim_cur != 0LL) {

            stack_size = (size_t)limit.rlim_cur;

        }

    }

    pthread_attr_t thread_attr;

    pthread_attr_init(&thread_attr);

    pthread_attr_setscope(&thread_attr, PTHREAD_SCOPE_SYSTEM);

    pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);

    if (stack_size > 0) {

        pthread_attr_setstacksize(&thread_attr, stack_size);

    }

    /* Start the thread that we will start the JVM on. */

    pthread_create(&vmthread, &thread_attr, startupJava, launchOptions);

    pthread_attr_destroy(&thread_attr);

    /* Create a a sourceContext to be used by our source that makes */

    /* sure the CFRunLoop doesn't exit right away */

    sourceContext.version = 0;

    sourceContext.info = NULL;

    sourceContext.retain = NULL;

    sourceContext.release = NULL;

    sourceContext.copyDescription = NULL;

    sourceContext.equal = NULL;

    sourceContext.hash = NULL;

    sourceContext.schedule = NULL;

    sourceContext.cancel = NULL;

    sourceContext.perform = &sourceCallBack;

    /* Create the Source from the sourceContext */

    CFRunLoopSourceRef sourceRef = CFRunLoopSourceCreate (NULL, 0, &sourceContext);

    /* Use the constant kCFRunLoopCommonModes to add the source to the set of objects */ 

    /* monitored by all the common modes */

    CFRunLoopAddSource (CFRunLoopGetCurrent(),sourceRef,kCFRunLoopCommonModes); 

    /* Park this thread in the runloop */

    CFRunLoopRun();

    return 0;

}