The sd-event is a event loop framework similar to libev, libuv, libevent, etc, I need to implement libev event loop for monitoring services. All the man pages I can find talk about the use of sd_bus_get_fd(), sd_bus_get_events() and sd_bus_get_timeout(), for example, on this page. Does anyone have a project example for using those three functions?
Don't have anything for libev but for libevent + sdbus , it goes something like this
//Global
static sd_bus *bus = NULL;
static struct event_base *base = NULL;
void bus_process(evutil_socket_t fd, short what, void *arg) {
sd_bus_process(bus, NULL);
}
void main() {
sd_bus_default_system(&bus);
sd_bus_request_name(bus, BUS_NAME, 0);
int fd = 0;
int events = 0;
uint64_t usec;
struct event *ev_read;
base = event_base_new()
fd = sd_bus_get_fd(bus);
events = sd_bus_get_events(bus);
sd_bus_get_timeout(bus, &usec);
evutil_make_socket_nonblocking(fd);
ev_read = event_new(base, fd, EV_READ|EV_PERSIST, bus_process, NULL);
event_add(ev_read, NULL);
event_base_dispatch(base);
// wont get here, loop is now running and processing
return;
}
Related
I got a problem when using a kernel extension that filters network traffic.
My code was written according to Apple's tcplognke example.
Everything goes OK but when I attempt to upload a file bigger than 500 kb - connection drops.
Here is simplified kext code:
errno_t tl_data_fn(void *cookie, socket_t so, const struct sockaddr *addr, mbuf_t *data, mbuf_t *control, sflt_data_flag_t flags, FilterSocketDataDirection direction) {
errno_t result = 0;
if (check_tag(data, gidtag, FILTER_TAG_TYPE, direction == FilterSocketDataDirectionIn ? IN_DONE : OUT_DONE)) {
return result;
}
if (!cookie) return result;
filter_cookie *f_cookie = get_filter_cookie(cookie);
uint32_t data_size = (uint32_t)mbuf_pkthdr_len(*data);
uint32_t offset = 0;
printf("tl_data_ft: %d", data_size);
while (offset < data_size) {
FilterNotification notification;
if (direction == FilterSocketDataDirectionIn) {
notification.event = FilterEventDataIn;
} else {
notification.event = FilterEventDataOut;
}
notification.socketId = (uint64_t)so;
notification.inputoutput.dataSize = min(data_size - offset, sizeof(notification.inputoutput.data));
mbuf_copydata(*data, offset, notification.inputoutput.dataSize, notification.inputoutput.data);
offset += notification.inputoutput.dataSize;
send_notification(f_cookie, ¬ification);
}
result = EJUSTRETURN;
if (result == EJUSTRETURN) {
mbuf_freem(*data);
if (control != NULL && *control != NULL)
mbuf_freem(*control);
}
return result;
}
errno_t tl_data_in_fn(void *cookie, socket_t so, const struct sockaddr *from, mbuf_t *data, mbuf_t *control, sflt_data_flag_t flags) {
return tl_data_fn(cookie, so, from, data, control, flags, FilterSocketDataDirectionIn);
}
errno_t tl_data_out_fn(void *cookie, socket_t so, const struct sockaddr *to, mbuf_t *data, mbuf_t *control, sflt_data_flag_t flags) {
return tl_data_fn(cookie, so, to, data, control, flags, FilterSocketDataDirectionOut);
}
And the user space code:
int s = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
//connect to driver
FilterNotification notification;
while (recv(s, ¬ification, sizeof(FilterNotification), 0) == sizeof(FilterNotification)) {
FilterClientResponse response;
response.socketId = notification.socketId;
response.direction = (notification.event == FilterEventDataIn) ? FilterSocketDataDirectionIn : FilterSocketDataDirectionOut;
response.dataSize = notification.inputoutput.dataSize;
memcpy(response.data, notification.inputoutput.data, notification.inputoutput.dataSize);
send(s, &response, sizeof(response), 0);
}
When I asked on apple develper forum, the developer said "I don’t see any attempt to handle send-side flow control here. Without that a file upload can easily eat up all of the available mbufs, and things will go badly from there" but there is not examples at all. Can someone help me? thanks.
The problem was in socket buffer. When I inject a lot of data very quickly, the buffer becomes full and inject_data_in/inject_data_out functions returns error.
The workaround is to store pending packets in kernel space (You can use TAILQ for example) and then, when socket becomes available for writing (To get this event you can use kqueue on OS X) continue injection
I'm trying to find a way to let the system tell me whenever there's a new entry in the USN Change Journal to track modifications made to files and directories on an NTFS volume (Server 2008/2012).
This way I don't have to constantly poll the journal and can just let my thread sleep until I get notified when there's a new change-event.
However, is there even such an interrupt?
The FSCTL_QUERY_USN_JOURNAL function doesn't specifically mention interrupts (events, notifications), nor have I been able to find another way to achieve this with less intensive poll-and-compare techniques.
I'm not a hard-core programmer so there may be simpler ways to tie these functions to interrupts that I'm not aware of.
Could I perhaps find out where the USN Change Journal is stored and watch that file with another process that can generate and interrupt on change?
https://msdn.microsoft.com/en-us/library/aa365729(v=vs.85).aspx
The code posted here blocks the executing thread till the new USN record is created in the Journal. When new records arrive, the thread awakens and you can process changes and/or notify listeners via a callback that filesystem has changed (in the example it just prints message to the console). Then the thread blocks again. This example uses one thread per volume (so for each volume, separate NTFSChangesWatcher class instance needed).
It is not specified which tools or language you use, so I will write as I did it. To run this code, create a Visual Studio C++ Win32 Console Application.
Create NTFSChangesWatcher class. Paste this code in NTFSChangesWatcher.h file (replacing auto-generated one):
#pragma once
#include <windows.h>
#include <memory>
class NTFSChangesWatcher
{
public:
NTFSChangesWatcher(char drive_letter);
~NTFSChangesWatcher() = default;
// Method which runs an infinite loop and waits for new update sequence number in a journal.
// The thread is blocked till the new USN record created in the journal.
void WatchChanges();
private:
HANDLE OpenVolume(char drive_letter);
bool CreateJournal(HANDLE volume);
bool LoadJournal(HANDLE volume, USN_JOURNAL_DATA* journal_data);
bool NTFSChangesWatcher::WaitForNextUsn(PREAD_USN_JOURNAL_DATA read_journal_data) const;
std::unique_ptr<READ_USN_JOURNAL_DATA> GetWaitForNextUsnQuery(USN start_usn);
bool NTFSChangesWatcher::ReadJournalRecords(PREAD_USN_JOURNAL_DATA journal_query, LPVOID buffer,
DWORD& byte_count) const;
std::unique_ptr<READ_USN_JOURNAL_DATA> NTFSChangesWatcher::GetReadJournalQuery(USN low_usn);
char drive_letter_;
HANDLE volume_;
std::unique_ptr<USN_JOURNAL_DATA> journal_;
DWORDLONG journal_id_;
USN last_usn_;
// Flags, which indicate which types of changes you want to listen.
static const int FILE_CHANGE_BITMASK;
static const int kBufferSize;
};
and this code in NTFSChangesWatcher.cpp file:
#include "NTFSChangesWatcher.h"
#include <iostream>
using namespace std;
const int NTFSChangesWatcher::kBufferSize = 1024 * 1024 / 2;
const int NTFSChangesWatcher::FILE_CHANGE_BITMASK =
USN_REASON_RENAME_NEW_NAME | USN_REASON_SECURITY_CHANGE | USN_REASON_BASIC_INFO_CHANGE | USN_REASON_DATA_OVERWRITE |
USN_REASON_DATA_TRUNCATION | USN_REASON_DATA_EXTEND | USN_REASON_CLOSE;
NTFSChangesWatcher::NTFSChangesWatcher(char drive_letter) :
drive_letter_(drive_letter)
{
volume_ = OpenVolume(drive_letter_);
journal_ = make_unique<USN_JOURNAL_DATA>();
bool res = LoadJournal(volume_, journal_.get());
if (!res) {
cout << "Failed to load journal" << endl;
return;
}
journal_id_ = journal_->UsnJournalID;
last_usn_ = journal_->NextUsn;
}
HANDLE NTFSChangesWatcher::OpenVolume(char drive_letter) {
wchar_t pattern[10] = L"\\\\?\\a:";
pattern[4] = static_cast<wchar_t>(drive_letter);
HANDLE volume = nullptr;
volume = CreateFile(
pattern, // lpFileName
// also could be | FILE_READ_DATA | FILE_READ_ATTRIBUTES | SYNCHRONIZE
GENERIC_READ | GENERIC_WRITE | SYNCHRONIZE, // dwDesiredAccess
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, // share mode
NULL, // default security attributes
OPEN_EXISTING, // disposition
// It is always set, no matter whether you explicitly specify it or not. This means, that access
// must be aligned with sector size so we can only read a number of bytes that is a multiple of the sector size.
FILE_FLAG_NO_BUFFERING, // file attributes
NULL // do not copy file attributes
);
if (volume == INVALID_HANDLE_VALUE) {
// An error occurred!
cout << "Failed to open volume" << endl;
return nullptr;
}
return volume;
}
bool NTFSChangesWatcher::CreateJournal(HANDLE volume) {
DWORD byte_count;
CREATE_USN_JOURNAL_DATA create_journal_data;
bool ok = DeviceIoControl(volume, // handle to volume
FSCTL_CREATE_USN_JOURNAL, // dwIoControlCode
&create_journal_data, // input buffer
sizeof(create_journal_data), // size of input buffer
NULL, // lpOutBuffer
0, // nOutBufferSize
&byte_count, // number of bytes returned
NULL) != 0; // OVERLAPPED structure
if (!ok) {
// An error occurred!
}
return ok;
}
bool NTFSChangesWatcher::LoadJournal(HANDLE volume, USN_JOURNAL_DATA* journal_data) {
DWORD byte_count;
// Try to open journal.
if (!DeviceIoControl(volume, FSCTL_QUERY_USN_JOURNAL, NULL, 0, journal_data, sizeof(*journal_data), &byte_count,
NULL)) {
// If failed (for example, in case journaling is disabled), create journal and retry.
if (CreateJournal(volume)) {
return LoadJournal(volume, journal_data);
}
return false;
}
return true;
}
void NTFSChangesWatcher::WatchChanges() {
auto u_buffer = make_unique<char[]>(kBufferSize);
auto read_journal_query = GetWaitForNextUsnQuery(last_usn_);
while (true) {
// This function does not return until new USN record created.
WaitForNextUsn(read_journal_query.get());
cout << "New entry created in the journal!" << endl;
auto journal_query = GetReadJournalQuery(read_journal_query->StartUsn);
DWORD byte_count;
if (!ReadJournalRecords(journal_query.get(), u_buffer.get(), byte_count)) {
// An error occurred.
cout << "Failed to read journal records" << endl;
}
last_usn_ = *(USN*)u_buffer.get();
read_journal_query->StartUsn = last_usn_;
// If you need here you can:
// Read and parse Journal records from the buffer.
// Notify an NTFSChangeObservers about journal changes.
}
}
bool NTFSChangesWatcher::WaitForNextUsn(PREAD_USN_JOURNAL_DATA read_journal_data) const {
DWORD bytes_read;
bool ok = true;
// This function does not return until new USN record created.
ok = DeviceIoControl(volume_, FSCTL_READ_USN_JOURNAL, read_journal_data, sizeof(*read_journal_data),
&read_journal_data->StartUsn, sizeof(read_journal_data->StartUsn), &bytes_read,
nullptr) != 0;
return ok;
}
unique_ptr<READ_USN_JOURNAL_DATA> NTFSChangesWatcher::GetWaitForNextUsnQuery(USN start_usn) {
auto query = make_unique<READ_USN_JOURNAL_DATA>();
query->StartUsn = start_usn;
query->ReasonMask = 0xFFFFFFFF; // All bits.
query->ReturnOnlyOnClose = FALSE; // All entries.
query->Timeout = 0; // No timeout.
query->BytesToWaitFor = 1; // Wait for this.
query->UsnJournalID = journal_id_; // The journal.
query->MinMajorVersion = 2;
query->MaxMajorVersion = 2;
return query;
}
bool NTFSChangesWatcher::ReadJournalRecords(PREAD_USN_JOURNAL_DATA journal_query, LPVOID buffer,
DWORD& byte_count) const {
return DeviceIoControl(volume_, FSCTL_READ_USN_JOURNAL, journal_query, sizeof(*journal_query), buffer, kBufferSize,
&byte_count, nullptr) != 0;
}
unique_ptr<READ_USN_JOURNAL_DATA> NTFSChangesWatcher::GetReadJournalQuery(USN low_usn) {
auto query = make_unique<READ_USN_JOURNAL_DATA>();
query->StartUsn = low_usn;
query->ReasonMask = 0xFFFFFFFF; // All bits.
query->ReturnOnlyOnClose = FALSE;
query->Timeout = 0; // No timeout.
query->BytesToWaitFor = 0;
query->UsnJournalID = journal_id_;
query->MinMajorVersion = 2;
query->MaxMajorVersion = 2;
return query;
}
Now you can use it (for example in the main function for testing):
#include "NTFSChangesWatcher.h"
int _tmain(int argc, _TCHAR* argv[])
{
auto watcher = new NTFSChangesWatcher('z');
watcher->WatchChanges();
return 0;
}
And console output should be like this on every change in the filesystem:
This code was slightly reworked to remove unrelated details and is a part of the Indexer++ project. So for more details, you can refer to the original code.
You can use Journal, but in this case I'd use easier method via registering a directory notification by calling the FindFirstChangeNotification or ReadDirectoryChangesW functions, see https://msdn.microsoft.com/en-us/library/aa364417.aspx
If you'd prefer to use Journal, this is - I think - the best introductory article with many examples. It is written for W2K, but those concepts are still valid: https://www.microsoft.com/msj/0999/journal/journal.aspx
I am toying around with a libwebsockets tutorial trying to make it such that, after it receives a message from a connection over a given protocol, it sends a response to all active connections implementing that protocol. I have used the function libwebsocket_callback_all_protocol but it is not doing what I think it should do from its name (I'm not quite sure what it does from the documentation).
The goal is to have two webpages open and, when info is sent from one, the result will be relayed to both. Below is my code - you'll see that libwebsocket_callback_all_protocol is called in main (which currently does nothing, I think....) :
#include <stdio.h>
#include <stdlib.h>
#include <libwebsockets.h>
#include <string.h>
static int callback_http(struct libwebsocket_context * this,
struct libwebsocket *wsi,
enum libwebsocket_callback_reasons reason, void *user,
void *in, size_t len)
{
return 0;
}
static int callback_dumb_increment(struct libwebsocket_context * this,
struct libwebsocket *wsi,
enum libwebsocket_callback_reasons reason,
void *user, void *in, size_t len)
{
switch (reason) {
case LWS_CALLBACK_ESTABLISHED: // just log message that someone is connecting
printf("connection established\n");
break;
case LWS_CALLBACK_RECEIVE: { // the funny part
// create a buffer to hold our response
// it has to have some pre and post padding. You don't need to care
// what comes there, libwebsockets will do everything for you. For more info see
// http://git.warmcat.com/cgi-bin/cgit/libwebsockets/tree/lib/libwebsockets.h#n597
unsigned char *buf = (unsigned char*) malloc(LWS_SEND_BUFFER_PRE_PADDING + len +
LWS_SEND_BUFFER_POST_PADDING);
int i;
// pointer to `void *in` holds the incomming request
// we're just going to put it in reverse order and put it in `buf` with
// correct offset. `len` holds length of the request.
for (i=0; i < len; i++) {
buf[LWS_SEND_BUFFER_PRE_PADDING + (len - 1) - i ] = ((char *) in)[i];
}
// log what we recieved and what we're going to send as a response.
// that disco syntax `%.*s` is used to print just a part of our buffer
// http://stackoverflow.com/questions/5189071/print-part-of-char-array
printf("received data: %s, replying: %.*s\n", (char *) in, (int) len,
buf + LWS_SEND_BUFFER_PRE_PADDING);
// send response
// just notice that we have to tell where exactly our response starts. That's
// why there's `buf[LWS_SEND_BUFFER_PRE_PADDING]` and how long it is.
// we know that our response has the same length as request because
// it's the same message in reverse order.
libwebsocket_write(wsi, &buf[LWS_SEND_BUFFER_PRE_PADDING], len, LWS_WRITE_TEXT);
// release memory back into the wild
free(buf);
break;
}
default:
break;
}
return 0;
}
static struct libwebsocket_protocols protocols[] = {
/* first protocol must always be HTTP handler */
{
"http-only", // name
callback_http, // callback
0, // per_session_data_size
0
},
{
"dumb-increment-protocol", // protocol name - very important!
callback_dumb_increment, // callback
0, // we don't use any per session data
0
},
{
NULL, NULL, 0, 0 /* End of list */
}
};
int main(void) {
// server url will be http://localhost:9000
int port = 9000;
const char *interface = NULL;
struct libwebsocket_context *context;
// we're not using ssl
const char *cert_path = NULL;
const char *key_path = NULL;
// no special options
int opts = 0;
// create libwebsocket context representing this server
struct lws_context_creation_info info;
memset(&info, 0, sizeof info);
info.port = port;
info.iface = interface;
info.protocols = protocols;
info.extensions = libwebsocket_get_internal_extensions();
info.ssl_cert_filepath = cert_path;
info.ssl_private_key_filepath = key_path;
info.gid = -1;
info.uid = -1;
info.options = opts;
info.user = NULL;
info.ka_time = 0;
info.ka_probes = 0;
info.ka_interval = 0;
/*context = libwebsocket_create_context(port, interface, protocols,
libwebsocket_get_internal_extensions,
cert_path, key_path, -1, -1, opts);
*/
context = libwebsocket_create_context(&info);
if (context == NULL) {
fprintf(stderr, "libwebsocket init failed\n");
return -1;
}
libwebsocket_callback_all_protocol(&protocols[1], LWS_CALLBACK_RECEIVE);
printf("starting server...\n");
// infinite loop, to end this server send SIGTERM. (CTRL+C)
while (1) {
libwebsocket_service(context, 50);
// libwebsocket_service will process all waiting events with their
// callback functions and then wait 50 ms.
// (this is a single threaded webserver and this will keep our server
// from generating load while there are not requests to process)
}
libwebsocket_context_destroy(context);
return 0;
}
I had the same problem, the libwebsocket_write on LWS_CALLBACK_ESTABLISHED generate some random segfault so using the mail list the libwebsockets developer Andy Green instructed me the correct way is to use libwebsocket_callback_on_writable_all_protocol, the file test-server/test-server.c in library source code shows sample of use.
libwebsocket_callback_on_writable_all_protocol(libwebsockets_get_protocol(wsi))
It worked very well to notify all instances, but it only call the write method in all connected instances, it do not define the data to send. You need to manage the data yourself. The sample source file test-server.c show a sample ring buffer to do it.
http://ml.libwebsockets.org/pipermail/libwebsockets/2015-January/001580.html
Hope it helps.
From what I can quickly grab from the documentation, in order to send a message to all clients, what you should do is store somewhere (in a vector, a hashmap, an array, whatever) the struct libwebsocket * wsi that you have access when your clients connect.
Then when you receive a message and want to broadcast it, simply call libwebsocket_write on all wsi * instances.
That's what I'd do, anyway.
I use ffmpeg to decode RTSP video.It likes that:
When it's on the end of file,it block in the av_read_frame() for a long time,why?
Various reasons can cause long blocking. But you can control the processing time for a I/O layer.
Use the structure AVFormatContext::interrupt_callback to set the interrupt handler.
class timeout_handler {
public:
timeout_handler(unsigned int t) : timeout_ms_(TimeoutMs){}
void reset(unsigned int 0) {
timeout_ms_ = TimeoutMs;
lastTime_ = my_get_local_time();
}
bool is_timeout(){
const my_time_duration actualDelay = my_get_local_time() - lastTime_;
return actualDelay > timeout_ms_;
}
static int check_interrupt(void * t) {
return t && static_cast<timeout_handler *>(t)->is_timeout();
}
public:
unsigned int timeout_ms_;
my_time_t lastTime_;
};
/// .................
AVFormatContext * ic;
timeout_handler * th = new timeout_handler(kDefaultTimeout);
/// .................
ic->interrupt_callback.opaque = (void*)th ;
ic->interrupt_callback.callback = &timeout_handler::check_interrupt;
/// open input
// avformat_open_input(ic, ... );
// etc
/// .................
/// before any I/O operations, for example:
th->reset(kDefaultTimeout);
int e = AVERROR(EAGAIN);
while (AVERROR(EAGAIN) == e)
e = av_read_frame(ic, &packet);
// If the time exceeds the limit, then the process interruped at the next IO operation.
This problem come because av_read_frame() stuck in network infinite loop
I got the same problem then I have used interrupt call back please refer the sample code
First initialize your context and set interrupt call back
AVFormatContext *_formatCtx;
//Initialize format context
_formatCtx=avformat_alloc_context();
//Initialize intrrupt callback
AVIOInterruptCB icb={interruptCallBack,(__bridge void *)(self)};
_formatCtx->interrupt_callback=icb;
now handle the interrupt in your callback
int interruptCallBack(void *ctx){
//once your preferred time is out you can return 1 and exit from the loop
if(timeout){
//exit
return 1;
}
//continue
return 0;
}
The Window-Procedure in the Win32 API must be static \ global function since it cannot take a class-object (the this) parameter. One can of-course use workarounds like a hWnd->object dictionary and such.
I wonder if D has a way to elegantly solve it, like create a tiny member function copy for each object (to call the object's real handler) or anonymous function that I can assign to WNDCLASS.lpfnWndProc (I know there are anonymous functions, but I cannot use the extern(Windows) property on them) ?
Can I do something like this :
class Window {
extern (Windows)
LRESULT delegate (HWND hWnd, UINT msg, WPARAM w, LPARAM l) MyWinProcDelegate;
this() {
MyWinProcDelegate = &Events;
}
extern (Windows)
LRESULT Events (HWND hWnd, UINT msg, WPARAM w, LPARAM l) {
MessageBoxA(null , "Success!!!" , null ,0);
return DefWindowProcA(hWnd, message, wParam, lParam);
}
}
(Omitting the registration\creation\msg-loop...)
The Events() doesn't seem to fire... am I missing something ?
Here I made this for you (based on BCS' answer):
version (Windows)
{
import std.c.windows.windows;
void makeExecutable(ubyte[] code)
{
DWORD old;
VirtualProtect(code.ptr, code.length, PAGE_EXECUTE_READWRITE, &old);
}
}
else
version (linux)
{
import core.sys.posix.sys.mman;
import core.sys.posix.unistd;
static if (!is(typeof(&mprotect)))
extern(C) int mprotect(void*, size_t, int);
void makeExecutable(ubyte[] code)
{
auto pageSize = sysconf(_SC_PAGE_SIZE);
auto address = ((cast(size_t)code.ptr) & ~(pageSize-1));
int pageCount =
(address/pageSize == (address+code.length)/pageSize) ? 1 : 2;
mprotect(cast(void*)address, pageSize * pageCount,
PROT_READ | PROT_WRITE | PROT_EXEC);
}
}
else
static assert(0, "TODO");
R function(A) delegate2function(R, A...)(R delegate(A) d)
{
enum size_t TEMPLATE1 = cast(size_t)0x01234567_01234567;
enum size_t TEMPLATE2 = cast(size_t)0x89ABCDEF_89ABCDEF;
static R functionTemplate(A args)
{
R delegate(A) d;
d.ptr = cast(typeof(d.ptr ))TEMPLATE1;
d.funcptr = cast(typeof(d.funcptr))TEMPLATE2;
return d(args);
}
static void functionTemplateEnd() {}
static void replaceWord(ubyte[] a, size_t from, size_t to)
{
foreach (i; 0..a.length - size_t.sizeof + 1)
{
auto p = cast(size_t*)(a.ptr + i);
if (*p == from)
{
*p = to;
return;
}
}
assert(0);
}
auto templateStart = cast(ubyte*)&functionTemplate;
auto templateEnd = cast(ubyte*)&functionTemplateEnd;
auto templateBytes = templateStart[0 .. templateEnd - templateStart];
// must allocate type with pointers, otherwise GC won't scan it
auto functionWords = new void*[(templateBytes.length / (void*).sizeof) + 3];
// store context in word-aligned boundary, so the GC can find it
functionWords[0] = d.ptr;
functionWords[1] = d.funcptr;
functionWords = functionWords[2..$];
auto functionBytes = (cast(ubyte[])functionWords)[0..templateBytes.length];
functionBytes[] = templateBytes[];
replaceWord(functionBytes, TEMPLATE1, cast(size_t)d.ptr );
replaceWord(functionBytes, TEMPLATE2, cast(size_t)d.funcptr);
makeExecutable(functionBytes);
return cast(typeof(return)) functionBytes.ptr;
}
void main()
{
import std.stdio;
auto context = 42;
void del(string s)
{
writeln(s);
writeln(context);
}
auto f = delegate2function(&del);
f("I am a pretty function");
}
Tested on Windows 32-bit and Linux 64-bit.
How about storing this in the window itself, with SetWindowLong?
One very un-portable solution would be to dynamically create a function that wraps the call. I would do this by writing a function that looks like this:
extern(C) RetType TestFn(Arg arg /* and any others */) {
Class c = cast(Class)(0xDEAD_BEEF);
return c.Method(arg);
}
You can then compile this function as un-optimized PIC, de-compile it, and find a byte sequence that can be mashed into what you need. The end result would be a type (likely a struct) that has a methoud returning a function pointer and that, when constructed, populates an internal void array with the bytes you found from the above step and pokes the object in question into the appropriate places.
A slightly more advanced solution would populate a delegate with both the object and the method pointer so both can be provided to the constructor. An even more advanced solution would template the type and take advantage of knowledge of the C and D calling conventions to dynamically generate the argument forwarding code.