100行代码搭建一个IO泄露监测框架

arduino复制代码public static void main(String[] args) {
    try (FileInputStream fis = new FileInputStream(new File("test.txt"))) {
        byte[] data = new byte[1024];
        int read = fis.read(data);
        //执行其他操纵
    } catch (Exception e) {
        e.printStackTrace();
    }
}

kotlin复制代码override fun create(context: Context) {
    FileInputStream("").use {
    	//执行某些操作
    }
}

java复制代码public class FileInputStream {

    private Object flag = null;

    public void open() {
        //打开文件流时赋值
        flag = "open";
    }

    public void close() throws Exception {
        //关闭文件流置空
        flag = null;
    }

    @Override
    protected void finalize() throws Throwable {
        super.finalize();
        //flag等于null，说明忘记执行close方法关闭流，io泄漏
        if (flag != null) {
            Throwable throwable = new Throwable("io leak");
            //执行异常日志的打印，或者回调给外部。
            //兜底流的关闭
            close();
        }
    }
}

arduino复制代码dependencies {
    implementation 'com.github.tiann:FreeReflection:3.1.0'
}

csharp复制代码@Override
protected void attachBaseContext(Context base) {
    super.attachBaseContext(base);
    Reflection.unseal(base);
}

arduino复制代码dependencies {
    implementation 'com.github.tiann:FreeReflection:3.1.0'

    implementation("androidx.startup:startup-runtime:1.1.1")
}

kotlin复制代码class IOLeakCanaryInstall : Initializer<Unit> {

    override fun create(context: Context) {
        //android p及以上非公开api允许调用
        Reflection.unseal(context)
        //初始化核心io泄漏监测
        IOLeakCanaryCore().init(context.applicationContext)
        Log.i(IOLeakCanaryCore.TAG, "IOLeakCanaryInstall install success!")
    }

    override fun dependencies(): MutableList<Class<out Initializer<*>>> = mutableListOf()
}

kotlin复制代码class IOLeakCanaryCore {

    companion object {
        const val TAG = "IOLeakCanary"

        lateinit var APPLICATION: Context
    }

    /**
     * CloseGuard原始的Reporter接口实现类DefaultReporter
     */
    private var mOriginalReporter: Any? = null

    fun init(application: Context) {
        APPLICATION = application
        val hookResult = tryHook()
        Log.i(TAG, "init: hookResult = $hookResult")
    }

    @SuppressLint("SoonBlockedPrivateApi")
    private fun tryHook(): Boolean {
        try {
            val closeGuardCls = Class.forName("dalvik.system.CloseGuard")
            val closeGuardReporterCls = Class.forName("dalvik.system.CloseGuard$Reporter")

            //拿到CloseGuard原始的Reporter接口实现类DefaultReporter
            val methodGetReporter = closeGuardCls.getDeclaredMethod("getReporter")
            mOriginalReporter = methodGetReporter.invoke(null)

            //获取setReporter的Method实例，便于后续反射该方法注入我们自定义的Report对象
            val methodSetReporter =
                closeGuardCls.getDeclaredMethod("setReporter", closeGuardReporterCls)
            //将CloseGuard的stackAndTrackingEnabled字段置为true，否则为false将不会调用自定义的Reporter对象
            val methodSetEnabled =
                closeGuardCls.getDeclaredMethod("setEnabled", Boolean::class.java)
            methodSetEnabled.invoke(null, true)
            //借助动态代理+反射注入我们自定义的Report对象
            val classLoader = closeGuardReporterCls.classLoader ?: return false
            methodSetReporter.invoke(
                null,
                Proxy.newProxyInstance(
                    classLoader,
                    arrayOf(closeGuardReporterCls),
                    IOLeakReporter()
                )
            )
            return true
        } catch (e: Throwable) {
            Log.e(TAG, "tryHook error: message = ${e.message}")
        }
        return false
    }

    /**
     * 拦截report并收集堆栈
     */
    inner class IOLeakReporter : InvocationHandler {

        override fun invoke(proxy: Any?, method: Method?, args: Array<out Any>?): Any? {
            if (method?.name == "report") {
                //io泄漏，收集堆栈并上报，其中args[1]就代表着上面的
                //CloseGuard#closerNameOrAllocationInfo字段，保存了流打开时的堆栈详细
                val stack = args?.get(1) as? Throwable ?: return null
                val stackTraceToString = stackTraceToString(stack.stackTrace)
            	//这里只是通过日志进行打印，有需要的可以定制这块逻辑，比如加入异常上报机制
                Log.i(TAG, "IOLeakReporter: invoke report = $stackTraceToString")
                return null
            }

            return method?.invoke(mOriginalReporter, args)
        }

        /**
    	* 处理堆栈
    	*/
        private fun stackTraceToString(arr: Array<StackTraceElement>?): String {
            val stacks = arr?.toMutableList()?.take(8) ?: return ""
            val sb = StringBuffer(stacks.size)
            for (stackTraceElement in stacks) {
                sb.append(stackTraceElement.toString()).appendLine()
            }
            return sb.toString()
        }
    }
}