我正在尝试在 Firefox 中使用 js-ctypes 来接收 USB 媒体/驱动器通知,但我遇到了一些问题,我无法判断是因为我对 Win32 API 非常缺乏经验还是在js-ctypes(或两者!)
我首先改编了我在 Alexandre Poirot 的博客上找到的一个例子:
该示例使用 js-ctypes 创建一个“仅消息”窗口,然后与 shell 服务交互以与 Windows 通知托盘进行通信。
这看起来很简单,所以在对 RegisterDeviceNotification 的优点进行一些研究之后对比SHChangeNotifyRegister ,我正在尝试调整该(有效!)示例以通过 SHChangeNotifyRegister
注册设备更新。
代码驻留在自举(无需重新启动)的 Firefox 扩展中(代码如下)。
WindowProc
的实现运行良好,与原始示例一样。我的 JavaScript 回调记录了进来的窗口消息(对于这个例子来说只是数字)。
问题:
首先,在扩展的 shutdown()
上调用 DestroyWindow
似乎会使 Firefox(几乎总是)崩溃。我应该在“仅消息”窗口上处理一些 Windows 消息以优雅地处理 DestryWindow
吗?
其次,尽管从控制台输出(下方)看来我从调用 SHGetSpecialFolderLocation
和 SHChangeNotifyRegister
中获得了有意义的值(返回值不是错误,PIDLISTITEM
指针是一些真实地址)我没有在 JavaScript 回调中收到设备/驱动器消息。
此外,我尝试重现 PIDLISTITEM
结构但无济于事(无法让 js-ctypes
在调用 SHChangeNotifyRegister
时识别它们>) 并且在研究了其他一些非 C++ 示例之后,似乎大多数人只是在使用 long*
来代替——我希望这是我误解的根源!
我已经通过类似的 C++ sample project from Microsoft 进行了验证当 SHChangeNotifyRegistration
成功并且我生成 USB 媒体事件(ny 插入和移除 USB 闪存媒体)时收到消息本身。
重现问题的最少代码如下:
安装.rdf:
<?xml version="1.0"?>
<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:em="http://www.mozilla.org/2004/em-rdf#">
<Description about="urn:mozilla:install-manifest">
<em:id>testwndproc@foo.com</em:id>
<em:type>2</em:type>
<em:name>TEST WNDPROC</em:name>
<em:version>1.0</em:version>
<em:bootstrap>true</em:bootstrap>
<em:unpack>true</em:unpack>
<em:description>Testing wndProc via JS-CTYPES on WIN32.</em:description>
<em:creator>David</em:creator>
<!-- Firefox Desktop -->
<em:targetApplication>
<Description>
<em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
<em:minVersion>4.0.*</em:minVersion>
<em:maxVersion>29.0.*</em:maxVersion>
</Description>
</em:targetApplication>
</Description>
</RDF>
bootstrap.js:
const Cc = Components.classes;
const Ci = Components.interfaces;
const Cu = Components.utils;
Components.utils.import("resource://gre/modules/ctypes.jsm");
let consoleService = Cc["@mozilla.org/consoleservice;1"]
.getService(Ci.nsIConsoleService);
function LOG(msg) {
consoleService.logStringMessage("TEST-WNDPROC: "+msg);
}
var WindowProcType, DefWindowProc, RegisterClass, CreateWindowEx,
DestroyWindow, SHGetSpecialFolderLocation, WNDCLASS, wndclass,
messageWin, libs = {};
var windowProcJSCallback = function(hWnd, uMsg, wParam, lParam) {
LOG("windowProc: "+JSON.stringify([uMsg, wParam, lParam]));
//
// TODO: decode uMsg, wParam, lParam to interpret
// the incoming ShChangeNotifyEntry messages!
//
return DefWindowProc(hWnd, uMsg, wParam, lParam);
};
function startup(data, reason) {
try {
LOG("loading USER32.DLL ...");
libs.user32 = ctypes.open("user32.dll");
LOG("loading SHELL32.DLL ...");
libs.shell32 = ctypes.open("shell32.dll");
LOG("registering callback ctype WindowProc ...");
WindowProc = ctypes.FunctionType(
ctypes.stdcall_abi, ctypes.int,
[ctypes.voidptr_t, ctypes.int32_t,
ctypes.int32_t, ctypes.int32_t]).ptr;
LOG("registering API CreateWindowEx ...");
CreateWindowEx = libs.user32.declare("CreateWindowExA",
ctypes.winapi_abi, ctypes.voidptr_t, ctypes.long,
ctypes.char.ptr, ctypes.char.ptr, ctypes.int,
ctypes.int, ctypes.int, ctypes.int, ctypes.int,
ctypes.voidptr_t, ctypes.voidptr_t, ctypes.voidptr_t,
ctypes.voidptr_t);
LOG("registering API DestroyWindow ...");
DestroyWindow = libs.user32.declare("DestroyWindow",
ctypes.winapi_abi, ctypes.bool, ctypes.voidptr_t);
/*
// previously using....
LOG("registering ctype SHITEMID ...");
var ShItemId = ctypes.StructType("ShItemId", [
{ cb: ctypes.unsigned_short },
{ abID: ctypes.uint8_t.array(1) }
]);
LOG("registering ctype ITEMIDLIST ...");
var ItemIDList = ctypes.StructType("ItemIDList", [
{ mkid: ShItemId }
]);
*/
LOG("registering ctype SHChangeNotifyEntry ...");
var SHChangeNotifyEntry = ctypes.StructType(
"SHChangeNotifyEntry", [
{ pidl: ctypes.long.ptr }, /* ItemIDList.ptr ??? */
{ fRecursive: ctypes.bool }
]);
LOG("registering API SHChangeNotifyRegister ...");
SHChangeNotifyRegister = libs.shell32.declare(
"SHChangeNotifyRegister", ctypes.winapi_abi,
ctypes.unsigned_long,
ctypes.voidptr_t, ctypes.int, ctypes.long,
ctypes.unsigned_int, ctypes.int,
SHChangeNotifyEntry.array() /* SHChangeNotifyEntry.ptr ??? */
);
LOG("registering ctype WNDCLASS ...");
WNDCLASS = ctypes.StructType("WNDCLASS", [
{ style : ctypes.uint32_t },
{ lpfnWndProc : WindowProc },
{ cbClsExtra : ctypes.int32_t },
{ cbWndExtra : ctypes.int32_t },
{ hInstance : ctypes.voidptr_t },
{ hIcon : ctypes.voidptr_t },
{ hCursor : ctypes.voidptr_t },
{ hbrBackground : ctypes.voidptr_t },
{ lpszMenuName : ctypes.char.ptr },
{ lpszClassName : ctypes.char.ptr }
]);
LOG("registering API SHGetSpecialFolderLocation ...");
SHGetSpecialFolderLocation = libs.shell32.declare(
"SHGetSpecialFolderLocation", ctypes.winapi_abi,
ctypes.long, ctypes.voidptr_t, ctypes.int,
ctypes.long.ptr /* ItemIDList.ptr ??? */
);
LOG("registering API RegisterClass ...");
RegisterClass = libs.user32.declare("RegisterClassA",
ctypes.winapi_abi, ctypes.voidptr_t, WNDCLASS.ptr);
LOG("registering API DefWindowProc ...");
DefWindowProc = libs.user32.declare("DefWindowProcA",
ctypes.winapi_abi, ctypes.int, ctypes.voidptr_t,
ctypes.int32_t, ctypes.int32_t, ctypes.int32_t);
LOG("instatiating WNDCLASS (using windowProcJSCallback) ...");
var cName = "class-testingmessageonlywindow";
wndclass = WNDCLASS();
wndclass.lpszClassName = ctypes.char.array()(cName);
wndclass.lpfnWndProc = WindowProc(windowProcJSCallback);
LOG("calling API: RegisterClass ...");
RegisterClass(wndclass.address());
LOG("calling API: CreateWindowEx ...");
var HWND_MESSAGE = -3; // message-only window
messageWin = CreateWindowEx(
0, wndclass.lpszClassName,
ctypes.char.array()("my-testing-window"),
0, 0, 0, 0, 0,
ctypes.voidptr_t(HWND_MESSAGE),
null, null, null
);
LOG("instantiating pidl ...");
var pidl = ctypes.long();
LOG("Prior to call, pidl = "+pidl);
LOG("calling API: SHGetSpecialFolderLocation ...");
var CSIDL_DESKTOP = 0;
var hr = SHGetSpecialFolderLocation(
messageWin,
CSIDL_DESKTOP,
pidl.address()
);
LOG("got back: "+hr);
LOG("After the call, pidl = "+pidl);
LOG("instantiating pschcne ...");
var SHCNE = SHChangeNotifyEntry.array(1);
var shcne = SHCNE();
shcne[0].pidl = pidl.address();
shcne[0].fRecursive = false;
var WM_SHNOTIFY = 1025; // 0x401
var SHCNE_DISKEVENTS = 145439; // 0x2381F
var SHCNE_DRIVEADD = 256; // 256
var SHCNE_DRIVEREMOVED = 128; // 128
var SHCNE_MEDIAINSERTED = 32; // 32
var SHCNE_MEDIAREMOVED = 64; // 64
var SHCNRF_ShellLevel = 2; // 0x0002
var SHCNRF_InterruptLevel = 1; // 0x0001
var SHCNRF_NewDelivery = 32768; // 0x8000
var nSources = SHCNRF_ShellLevel |
SHCNRF_InterruptLevel |
SHCNRF_NewDelivery;
var lEvents = SHCNE_DISKEVENTS | SHCNE_DRIVEADD |
SHCNE_DRIVEREMOVED | SHCNE_MEDIAINSERTED |
SHCNE_MEDIAREMOVED;
var uMsg = WM_SHNOTIFY;
LOG("DEBUG: nSources="+nSources);
LOG("DEBUG: lEvents="+lEvents);
LOG("DEBUG: uMsg="+uMsg);
LOG("calling API: SHChangeNotifyRegister ...");
var reg_id = SHChangeNotifyRegister(
messageWin, nSources, lEvents, uMsg, 1, shcne
);
if (reg_id > 0) {
LOG("SUCCESS: Registered with ShellService for "+
"DRIVE/MEDIA notifications! reg-id: "+reg_id);
} else {
LOG("ERROR: Couldn't register for DRIVE/MEDIA "+
"notifications from ShellService!");
}
LOG("done!");
} catch (e) {
LOG("ERROR: "+e);
}
}
function shutdown(data, reason) {
if (reason == APP_SHUTDOWN) return;
try {
//LOG("destroying hidden window... ");
//DestroyWindow(messageWin); // crash!!!
LOG("unloading USER32.DLL ...");
libs.user32.close();
LOG("unloading SHELL32.DLL ...");
libs.shell32.close();
LOG("done!");
} catch (e) {
LOG("ERROR: "+e);
}
}
控制台输出:
17:08:25.518 TEST-WNDPROC: loading USER32.DLL ...
17:08:25.518 TEST-WNDPROC: loading SHELL32.DLL ...
17:08:25.518 TEST-WNDPROC: registering callback ctype WindowProc ...
17:08:25.518 TEST-WNDPROC: registering API CreateWindowEx ...
17:08:25.518 TEST-WNDPROC: registering API DestroyWindow ...
17:08:25.518 TEST-WNDPROC: registering ctype SHChangeNotifyEntry ...
17:08:25.518 TEST-WNDPROC: registering API SHChangeNotifyRegister ...
17:08:25.518 TEST-WNDPROC: registering ctype WNDCLASS ...
17:08:25.518 TEST-WNDPROC: registering API SHGetSpecialFolderLocation ...
17:08:25.518 TEST-WNDPROC: registering API RegisterClass ...
17:08:25.518 TEST-WNDPROC: registering API DefWindowProc ...
17:08:25.519 TEST-WNDPROC: instatiating WNDCLASS (using windowProcJSCallback) ...
17:08:25.519 TEST-WNDPROC: calling API: RegisterClass ...
17:08:25.519 TEST-WNDPROC: calling API: CreateWindowEx ...
17:08:25.519 TEST-WNDPROC: windowProc: [36,0,2973696]
17:08:25.519 TEST-WNDPROC: windowProc: [129,0,2973652]
17:08:25.519 TEST-WNDPROC: windowProc: [131,0,2973728]
17:08:25.519 TEST-WNDPROC: windowProc: [1,0,2973608]
17:08:25.519 TEST-WNDPROC: instantiating pidl ...
17:08:25.519 TEST-WNDPROC: Prior to call, pidl = ctypes.long(ctypes.Int64("0"))
17:08:25.519 TEST-WNDPROC: calling API: SHGetSpecialFolderLocation ...
17:08:25.519 TEST-WNDPROC: got back: 0
17:08:25.519 TEST-WNDPROC: After the call, pidl = ctypes.long(ctypes.Int64("224974424"))
17:08:25.519 TEST-WNDPROC: instantiating pschcne ...
17:08:25.519 TEST-WNDPROC: DEBUG: [nSources=32771][lEvents=145919][uMsg=1025]
17:08:25.519 TEST-WNDPROC: calling API: SHChangeNotifyRegister ...
17:08:25.520 TEST-WNDPROC: SUCCESS: Registered with ShellService for DRIVE/MEDIA
notifications! reg-id: 15
17:08:25.520 TEST-WNDPROC: done!
----- &< -------
17:09:31.391 TEST-WNDPROC: unloading USER32.DLL ...
17:09:31.391 TEST-WNDPROC: unloading SHELL32.DLL ...
17:09:31.391 TEST-WNDPROC: done!
最佳答案
对于其他想要这样做的人,我发布了一个令人讨厌的hack 解决方法。 (我不会接受这个答案,希望最终有人会发布正确的做法)。
经过大量阅读后,我唯一推荐的另一种枚举和/或确定 USB 卷状态的方法是使用 WMI。以下 WQL
查询起到了作用:
select Caption, Size from win32_LogicalDisk where DriveType = 2
要从 C++ 使用 WQL,您必须使用 COM。从 js-ctypes
使用它并不是微不足道的工程任务。您需要安排从 ChromeWorker
加载和使用 DLL,有时我发现我特别需要确保从正确的 Firefox 线程调用 JavaScript 回调函数,并且 COM 是未在多线程单元中初始化。
Caption
是盘符。似乎一旦弹出 USB 驱动器,Size
报告为零。
然后相当简单地在 ChromeWorker
线程内的轮询循环中调用它,模拟对已安装卷的更改,并在我的 DOM 窗口中引发合成的 USB-Mounted/Ejected/Removed 事件.
不幸的是,这有一个巨大问题。如果您插入 USB 闪存驱动器,Windows 通常需要 2 到 30 秒(取决于大小)进行安装。在此期间(特别是在第一秒左右),如果您运行上述 WQL
查询,它将阻止 USB 音量从操作系统挂载 (? !?) 有效地导致拒绝服务。
无论这让我多么怀疑,在询问之后我确信如果我使用异步
(而不是同步
或半同步
)WQL查询,拒绝服务不会发生。
SELECT * FROM __instanceoperationevent WITHIN 2
WHERE TargetInstance ISA 'Win32_LogicalDisk' and TargetInstance.DriveType = 2
如果 __instanceoperationevent
ISA __InstanceCreationEvent
则卷已添加。如果 __instanceoperationevent
ISA __InstanceDeletionEvent
则该卷已删除。
似乎当 __instanceoperationevent
ISA __InstanceModificationEvent
卷被弹出时,但我不清楚还有什么其他类型的操作可以导致这个。由于此时该卷仍处于连接状态,因此使用第一个 同步
查询(上文)来确定性地查询其 Size
可能是安全的。
异步
WQL 查询似乎可以通过两种不同的方式调用,作为临时
或永久
WMI 事件消费者。差别不大,但是permanent
过滤器+消费者似乎是被推荐的并且似乎不会与 WQL 查询“配额”发生冲突。
无论哪种方式,都没有明智的方法来使用通过 js-ctypes
传入的 JavaScript 回调来处理生成的 WMI 事件。 :-( 剩下的就是寻找一种方法来使用事件,然后将它们传回 Firefox。
我最终使用了基于 DBD::WMI 的 Strawberry perl 脚本根据@Corion 对 a perlmonks question 的回答每 2 秒异步轮询一次事件,然后使用 IO::Socket::INET将结果通过 TCP 套接字发送给 Firefox。 (你完全可以用任何语言来做到这一点——我碰巧对 Perl 很满意)。
然后我在我的插件中实现了 nsIServerSocket
,等待 \n
终止行来解析收集到的输入并执行与上述相同的建模和合成事件。
关于javascript - jsctypes - 将 SHChangeNotifyRegister 用于 MEDIA/DRIVE 事件的问题,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21399770/