ThreadUtilities.m

/*
 * Copyright (c) 2011, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#import <AppKit/AppKit.h>
#import <objc/message.h>

#import "ThreadUtilities.h"


// The following must be named "jvm", as there are extern references to it in AWT
JavaVM *jvm = NULL;
static JNIEnv *appKitEnv = NULL;
static jobject appkitThreadGroup = NULL;
static NSString* JavaRunLoopMode = @"javaRunLoopMode";
static NSArray<NSString*> *javaModes = nil;

static inline void attachCurrentThread(void** env) {
    if ([NSThread isMainThread]) {
        JavaVMAttachArgs args;
        args.version = JNI_VERSION_1_4;
        args.name = "AppKit Thread";
        args.group = appkitThreadGroup;
        (*jvm)->AttachCurrentThreadAsDaemon(jvm, env, &args);
    } else {
        (*jvm)->AttachCurrentThreadAsDaemon(jvm, env, NULL);
    }
}

@implementation ThreadUtilities

+ (void)initialize {
    /* All the standard modes plus ours */
    javaModes = [[NSArray alloc] initWithObjects:NSDefaultRunLoopMode,
                                           NSModalPanelRunLoopMode,
                                           NSEventTrackingRunLoopMode,
                                           JavaRunLoopMode,
                                           nil];
}

+ (JNIEnv*)getJNIEnv {
AWT_ASSERT_APPKIT_THREAD;
    if (appKitEnv == NULL) {
        attachCurrentThread((void **)&appKitEnv);
    }
    return appKitEnv;
}

+ (JNIEnv*)getJNIEnvUncached {
    JNIEnv *env = NULL;
    attachCurrentThread((void **)&env);
    return env;
}

+ (void)detachCurrentThread {
    (*jvm)->DetachCurrentThread(jvm);
}

+ (void)setAppkitThreadGroup:(jobject)group {
    appkitThreadGroup = group;
}

/* This is needed because we can't directly pass a block to
 * performSelectorOnMainThreadWaiting .. since it expects a selector
 */
+ (void)invokeBlock:(void (^)())block {
  block();
}

/*
 * When running a block where either we don't wait, or it needs to run on another thread
 * we need to copy it from stack to heap, use the copy in the call and release after use.
 * Do this only when we must because it could be expensive.
 * Note : if waiting cross-thread, possibly the stack allocated copy is accessible ?
 */
+ (void)invokeBlockCopy:(void (^)(void))blockCopy {
  blockCopy();
  Block_release(blockCopy);
}

+ (void)performOnMainThreadWaiting:(BOOL)wait block:(void (^)())block {
    if ([NSThread isMainThread] && wait == YES) {
        block();
    } else {
        if (wait == YES) {
            [self performOnMainThread:@selector(invokeBlock:) on:self withObject:block waitUntilDone:YES];
        } else {
            void (^blockCopy)(void) = Block_copy(block);
            [self performOnMainThread:@selector(invokeBlockCopy:) on:self withObject:blockCopy waitUntilDone:NO];
        }
    }
}

+ (void)performOnMainThread:(SEL)aSelector on:(id)target withObject:(id)arg waitUntilDone:(BOOL)wait {
    if ([NSThread isMainThread] && wait == YES) {
        [target performSelector:aSelector withObject:arg];
    } else {
        [target performSelectorOnMainThread:aSelector withObject:arg waitUntilDone:wait modes:javaModes];
    }
}

+ (NSString*)javaRunLoopMode {
    return JavaRunLoopMode;
}

@end


void OSXAPP_SetJavaVM(JavaVM *vm)
{
    jvm = vm;
}