Now I'm developing a usb-serial application with its dll in Node.js.
This dll returns INVALID_HANDLE_VALUE, if it fails to open com port. So I want to handle the ret value in Node.js. In this case, How do I handle below ?
I'm not sure how do I compare the ret value and SlowBuffer.
DLL
#define INVALID_HANDLE_VALUE ((HANDLE)(LONG_PTR)-1
typedef HANDLE (*OPEN)(int);
__declspec(dllexport) HANDLE opencom(int ncom)
Node.js with node-ffi
var ffi = require('ffi');
var lib = ffi.Library('serialmw.dll', {
'opencom' : ['pointer', ['int']]
});
var hcom = null;
hcom = lib.opencom(1);
console.log(hcom); // <SlowBuffer#0xFFFFFFFFFFFFFFFF >
A SlowBuffer is just a Buffer which is just a bunch of raw binary bytes. If you want to compare two Buffers byte-for-byte, you will have to use a for-loop or something like the buffertools' compare() with both Buffers.
Related
I understand eval string-to-function is impossible to use on the browsers' application programming interfaces, but there must be another strategy to use third party dependencies without node.js on v8 engine, given Cloudflare does it in-house, unless they disable the exclusive method by necessity or otherwise on their edge servers for Workers. I imagine I could gather the AST of the commonjs module, as I was able to by rollup watch, but what might the actual steps be, by tooling? I mention AMD for it seems to rely on string-to-function (to-which I've notice Mozilla MDN says nothing much about it).
I have been exploring the require.js repositories, and they either use eval or AST
function DEFNODE(type, props, methods, base) {
if (arguments.length < 4) base = AST_Node;
if (!props) props = [];
else props = props.split(/\s+/);
var self_props = props;
if (base && base.PROPS) props = props.concat(base.PROPS);
var code = "return function AST_" + type + "(props){ if (props) { ";
for (var i = props.length; --i >= 0; ) {
code += "this." + props[i] + " = props." + props[i] + ";";
}
var proto = base && new base();
if ((proto && proto.initialize) || (methods && methods.initialize))
code += "this.initialize();";
code += "}}";
//constructor
var cnstor = new Function(code)();
if (proto) {
cnstor.prototype = proto;
cnstor.BASE = base;
}
if (base) base.SUBCLASSES.push(cnstor);
cnstor.prototype.CTOR = cnstor;
cnstor.PROPS = props || null;
cnstor.SELF_PROPS = self_props;
cnstor.SUBCLASSES = [];
if (type) {
cnstor.prototype.TYPE = cnstor.TYPE = type;
}
if (methods)
for (i in methods)
if (HOP(methods, i)) {
if (/^\$/.test(i)) {
cnstor[i.substr(1)] = methods[i];
} else {
cnstor.prototype[i] = methods[i];
}
}
//a function that returns an object with [name]:method
cnstor.DEFMETHOD = function (name, method) {
this.prototype[name] = method;
};
if (typeof exports !== "undefined") exports[`AST_${type}`] = cnstor;
return cnstor;
}
var AST_Token = DEFNODE(
"Token",
"type value line col pos endline endcol endpos nlb comments_before file raw",
{},
null
);
https://codesandbox.io/s/infallible-darwin-8jcl2k?file=/src/mastercard-backbank/uglify/index.js
https://www.youtube.com/watch?v=EF7UW9HxOe4
Is it possible to make a C++ addon just to add a default object for
node.js named exports or am I Y’ing up the wrong X
'.so' shared library for C++ dlopen/LoadLibrary (or #include?)
“I have to say that I'm amazed that there is code out there that loads one native addon from another native addon! Is it done by acquiring and then calling an instance of the require() function, or perhaps by using uv_dlopen() directly?”
N-API: An api for embedding Node in applications
"[there is no ]napi_env[ just yet]."
node-api: allow retrieval of add-on file name - Missing module in Init
Andreas Rossberg - is AST parsing, or initialize node.js abstraction for native c++, enough?
v8::String::NewFromUtf8(isolate, "Index from C++!");
Rising Stack - Node Source
"a macro implicit" parameter - bridge object between
C++ and JavaScript runtimes
extract a function's parameters and set the return value.
#include <nan.h>
int build () {
NAN_METHOD(Index) {
info.GetReturnValue().Set(
Nan::New("Index from C++!").ToLocalChecked()
);
}
}
// Module initialization logic
NAN_MODULE_INIT(Initialize) {
/*Export the `Index` function
(equivalent to `export function Index (...)` in JS)*/
NAN_EXPORT(target, Index);
}
New module "App" Initialize function from NAN_MODULE_INIT (an atomic?-macro)
"__napi_something doesn't exist."
"node-addon-API module for C++ code (N-API's C code's headers)"
NODE_MODULE(App, Initialize);
Sep 17, 2013, 4:42:17 AM to v8-u...#googlegroups.com "This comes up
frequently, but the answer remains the same: scrap the idea. ;)
Neither the V8 parser nor its AST are designed for external
interfacing. In particular (1) V8's AST does not necessarily reflect
JavaScript syntax 1-to-1, (2) we change it all the time, and (3) it
depends on various V8 internals. And since all these points are
important for V8, don't expect the situation to change.
/Andreas"
V8 c++: How to import module via code to script context (5/28/22, edit)
"The export keyword may only be used in a module interface unit.
The keyword is attached to a declaration of an entity, and causes that
declaration (and sometimes the definition) to become visible to module
importers[ - except for] the export keyword in the module-declaration, which is just a re-use of the keyword (and does not actually “export” ...entities)."
SyntheticModule::virtual
ScriptCompiler::CompileModule() - "Corresponds to the ParseModule abstract operation in the ECMAScript specification."
Local<Function> foo_func = ...;//external
Local<Module> module = Module::CreateSyntheticModule(
isolate, name,
{String::NewFromUtf8(isolate, "foo")},
[](Local<Context> context, Local<Module> module) {
module->SetSyntheticModuleExport(
String::NewFromUtf8(isolate, "foo"), foo_func
);
});
Context-Aware addons from node.js' commonjs modules
export module index;
export class Index {
public:
const char* app() {
return "done!";
}
};
import index;
import <iostream>;
int main() {
std::cout << Index().app() << '\n';
}
node-addon-api (new)
native abstractions (old)
"Thanks to the crazy changes in V8 (and some in Node core), keeping native addons compiling happily across versions, particularly 0.10 to 0.12 to 4.0, is a minor nightmare. The goal of this project is to store all logic necessary to develop native Node.js addons without having to inspect NODE_MODULE_VERSION and get yourself into a macro-tangle[ macro = extern atomics?]."
Scope Isolate (v8::Isolate), variable Local (v8::Local)
typed_array_to_native.cc
"require is part of the Asynchronous Module Definition AMD API[, without "string-to-function" eval/new Function()],"
node.js makes objects, for it is written in C++.
"According to the algorithm, before finding
./node_modules/_/index.js, it tried looking for express in the
core Node.js modules. This didn’t exist, so it looked in node_modules,
and found a directory called _. (If there was a
./node_modules/_.js, it would load that directly.) It then
loaded ./node_modules/_/package.json, and looked for an exports
field, but this didn’t exist. It also looked for a main field, but
this didn’t exist either. It then fell back to index.js, which it
found. ...require() looks for node_modules in all of the parent directories of the caller."
But java?
I won't accept this answer until it works, but this looks promising:
https://developer.oracle.com/databases/nashorn-javascript-part1.html
If not to run a jar file or something, in the Worker:
https://github.com/nodyn/jvm-npm
require and build equivalent in maven, first, use "dist/index.js".
Specifically: [ScriptEngineManager][21]
https://stackoverflow.com/a/15787930/11711280
Actually: js.commonjs-require experimental
https://docs.oracle.com/en/graalvm/enterprise/21/docs/reference-manual/js/Modules/
Alternatively/favorably: commonjs builder in C (v8 and node.js)
https://www.reddit.com/r/java/comments/u7elf4/what_are_your_thoughts_on_java_isolates_on_graalvm/
Here I will explore v8/node.js src .h and .cc for this purpose
https://codesandbox.io/s/infallible-darwin-8jcl2k?file=/src/c.cpp
I'm curious why there is near machine-level C operability in Workers if not to use std::ifstream, and/or build-locally, without node.js require.
My code for loading the file from resource is given below
void LoadFileInResource(int name, int type, DWORD& size, const char*& data)
{
HMODULE handle = ::GetModuleHandle(NULL);
HRSRC rc = ::FindResource(handle, MAKEINTRESOURCE(name),MAKEINTRESOURCE(type));
HGLOBAL rcData = ::LoadResource(handle, rc);
size = ::SizeofResource(handle, rc);
data = static_cast<const char*>(::LockResource(rcData));
}
This code works perfect if its just an application. When the same code is used as a DLL, I am getting null in rc, which is post the FindResource.
I have defined the symbols in resourceful file as shows below:
#define TEXTFILE 256
#define IDR_MYTEXTFILE 105
Also the file which I need to add is defined in rc file:
IDR_MYTEXTFILE TEXTFILE "C:/Docs/Lib.XML"
As I mentioned earlier, this code is perfectly working when its an application, converting it to DLL is creating issue.
LoadFileInResource function is called as given below:
LoadFileInResource(IDR_MYTEXTFILE, TEXTFILE, size, data);
I have a DLL, declare like this:
READIDCARD_API typedef void(*PIDDataCB)(char * pData);
READIDCARD_API int initReadIdcard(PIDDataCB func);
DLL Download：the 32-bit dll file (google drive download)
the dll file worked well, when use QT load it and convert data use local8bit
I use node.js and node-ffi to load it
const ffi = require('ffi');
const ref = require("ref");
let ReadIdcard = ffi.Library('./ReadIdcard.dll', {
'initReadIdcard': ['int', ['pointer']]
});
let callback = ffi.Callback('void', ['string'],
function(data) {
console.log("data: ", data);
});
console.log("registering the callback");
let z = ReadIdcard.initReadIdcard(callback);
console.log('done');
// Make an extra reference to the callback pointer to avoid GC
process.on('exit', function() {
callback
});
My environment：Windows7 64bit / Node.js 32bit
run the code, and the ������˼�������� is Chinese before the "sorry" string
What should I do, or convert it to display right, thank you.
You should use correct encoding to log the string.
Default encoding is utf8, but Chinese should be one of these utf16/gb18030/ gbk/gb2312.
I need to write an extension for Thunderbird. The extension will be used to do some text mining and relies on native C++ code. From my understanding, Thunderbird extensions are now mostly written in JavaScript and XPCOM is being slowly deprecated (https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM).
Besides, XPCOM seems a bit heavy and I would like an easier path to access my C++ code. Are there any alternatives besides XPCOM to access C++ code from a thunderbird extension?
Thanks!
Take a look at js-ctypes (https://developer.mozilla.org/en-US/docs/Mozilla/js-ctypes)
Little example:
Components.utils.import("resource://gre/modules/FileUtils.jsm");
Components.utils.import("resource://gre/modules/ctypes.jsm")
// path to C++ lib (/home/username/.thunderbird/PROFILE/extensions/EXTNAME/components/lib.so)
var libPath = FileUtils.getFile("ProfD", ["extensions", "EXTNAME", "components", "lib.so"]);
var lib = ctypes.open(libPath.path);
var libFunction = lib.declare("concatStrings", // function name in C++ code
ctypes.default_abi,
ctypes.char.ptr, // return value
ctypes.char.ptr, // param1
ctypes.char.ptr // param2
);
var ret = libFunction("abc", "efg");
lib.close()
Also be aware that C++ compiler does name mangling due to function overloading so your function name might be 'concatStrings' in C++ code, but then in assembly it might be something like '_123concatStrings'. To prevent this declare your function like:
extern "C" const char * concatStrings ( const char * str1, const char * str2 );
I hooked native api ZwCreateFile, and wdk doc says windows use ZwCreateFile to create or open a directory. I can detect the operation of opening testdir, but i failed to stop the open directory operation.
My code of my own FakeZwCreateFile like this：
NTSTATUS FakeZwOpenFile(
OUT PHANDLE FileHandle,
IN ACCESS_MASK DesiredAccess,
IN POBJECT_ATTRIBUTES ObjectAttributes,
OUT PIO_STATUS_BLOCK IoStatusBlock,
IN ULONG ShareAccess,
IN ULONG OpenOptions
)
{
NTSTATUS rtStatus = STATUS_SUCCESS;
UNICODE_STRING test = RTL_CONSTANT_STRING(L"\\??\\c:\\testdir");
if (!RtlCompareUnicodeString(ObjectAttributes->ObjectName, &test, TRUE))
{
DbgPrint("%wZ\n", &test);
FileHandle = NULL;
IoStatusBlock->Status = rtStatus = STATUS_ACCESS_DENIED;
goto exit;
}
Orig:
OrigZwOpenFile = (NTOPENFILE)oldServiceAddr[SYSTEM_INDEX(ZwOpenFile)];
rtStatus = OrigZwOpenFile(
FileHandle,
DesiredAccess,
ObjectAttributes,
IoStatusBlock,
ShareAccess,
OpenOptions
);
exit:
return rtStatus;
}
Why i failed to stop opening the c:\testdir directory?? And what shoud i do to intercept the operations of creating new folders????
In this case is better to use File System Filter Drivers instead of SSDT hooking, Because FS Filter Drivers work correctly in 64Bit version of windows but SSDT only can use in 32Bit (If you can bypass windows Patch Guard then you can use SSDT hook in 32Bit) !