javasharedmemory's Introduction

JavaSharedMemory

Shared memory between processes. (Java, C++, Rust, etc.) Based on Java 19 Foreign Function & Memory API

Support Windows (CreateFileMapping), Linux and macOS (mmap and shmget).

Note Compared with standard input and output (anonymous pipes) on Windows, more than 2x performance improvement.

Usage

Java

repositories {
    maven { url 'https://www.jitpack.io' }
}

dependencies {
    implementation 'com.github.ShirasawaSama:JavaSharedMemory:<version>'
}

tasks.withType(JavaCompile).each {
    it.options.compilerArgs.add('--enable-preview')
}

// kotlin script
// tasks.withType<JavaCompile> {
//     options.compilerArgs = options.compilerArgs + listOf("--enable-preview")
// }

import cn.apisium.shm;

public class Main {
    public static void main(String[] args) {
        // var shm = SharedMemory.open("test", 1024)
        try (var shm = SharedMemory.create("test", 1024)) {
            var buf = shm.toByteBuffer();
            buf.put("Hello, World!".getBytes());
        }
    }
}

C++

git submodule add https://github.com/ShirasawaSama/JavaSharedMemory.git

CMakeLists.txt:

add_subdirectory(JavaSharedMemory)
target_link_libraries(${PROJECT_NAME} java_shared_memory)

main.cpp:

#include <jshm.h>

int main() {
    auto shm = jshm::shared_memory::create("test", 1024);
    // auto shm = jshm::shared_memory::open("test", 1024);
    strcpy((char*)shm->address(), "Hello, World!");
    delete shm;
}

Author

Shirasawa

License

MIT

javasharedmemory's People

Contributors

Stargazers

Watchers

javasharedmemory's Issues

Java21 SharedMemory.open Exception

win10

SharedMemory sharedMemory = SharedMemory.create("test", 1024);
try (var shm = sharedMemory) {
var buf = shm.toByteBuffer();
buf.put(bytes);

}
System.out.println("write success ");
sharedMemory.close();
SharedMemory test = SharedMemory.open("test", 1024);  // <---
System.out.println(test.getSize());

WindowsSharedMemory:69

        hMapFile = isCreate ? (MemorySegment) createFileMapping.invokeExact(
                (MemorySegment) MemorySegment.ofAddress(-1),
                MemorySegment.NULL,
                PAGE_READWRITE | SEC_COMMIT,
                0,
                size,
                (MemorySegment) Arena.ofAuto().allocateUtf8String(name)
        ) : (MemorySegment) openFileMapping.invokeExact(SECTION_MAP_WRITE | SECTION_MAP_READ, 0, name);// <--------
        if (hMapFile.address() == 0) throw new IllegalStateException("CreateFileMapping failed.");

java.lang.RuntimeException: java.lang.invoke.WrongMethodTypeException: handle's method type (int,int,MemorySegment)MemorySegment but found (int,int,String)MemorySegment
	at cn.apisium.shm.SharedMemory.init(SharedMemory.java:86)
	at cn.apisium.shm.SharedMemory.open(SharedMemory.java:54)
	at top.war3rpg.Main.main(Main.java:47)
Caused by: java.lang.invoke.WrongMethodTypeException: handle's method type (int,int,MemorySegment)MemorySegment but found (int,int,String)MemorySegment
	at java.base/java.lang.invoke.Invokers.newWrongMethodTypeException(Invokers.java:522)
	at java.base/java.lang.invoke.Invokers.checkExactType(Invokers.java:531)
	at cn.apisium.shm.impl.WindowsSharedMemory.<init>(WindowsSharedMemory.java:69)
	at cn.apisium.shm.SharedMemory.init(SharedMemory.java:81)
	... 2 more

Recommend Projects