Bug in httpclient

[zeitbit]

Running httpclient compiled in a DLL crashes after the first execution:

Traceback (most recent call last)                                                                                      
C:\Test\lib.nim(7) fnNet   
C:\Nim\lib\pure\httpclient.nim(1074) getContent                                                           
C:\Nim\lib\pure\httpclient.nim(1069) get                                                                  
C:\Nim\lib\pure\httpclient.nim(1045) request                                                              
C:\Nim\lib\pure\httpclient.nim(1029) request                                                              
C:\Nim\lib\pure\httpclient.nim(979) requestAux                                                            
C:\Nim\lib\pure\httpcore.nim(180) hasKey                                                                  
C:\Nim\lib\pure\collections\tables.nim(880) hasKey                                                        
SIGSEGV: Illegal storage access. (Attempt to read from nil?) 

Here is a minimal example to reproduce the crash:

C code (EXE):

#include "windows.h"

typedef void (*DLLPROC)();

int main()
{
    HINSTANCE dll;

    dll = LoadLibrary("lib.dll");

    if (dll)
    {
        DLLPROC fnNet = (DLLPROC) GetProcAddress(dll, "fnNet");

        if (fnNet)
        {
            for (int i = 0; i < 100; i++)
            {
                (*fnNet)();
            }
        }

        FreeLibrary(dll);
    }
}

Nim code (DLL):

import httpclient

proc fnNet*() {.exportc, dynlib.} =
    var httpClient = newHttpClient()

    try:
        discard httpClient.getContent("http://google.com")
        echo "ok"
    except:
        echo getCurrentExceptionMsg()

Without try/except the traceback is:

Traceback (most recent call last)                                                                                      
C:\Test\lib.nim(6) fnNet                                   
C:\Nim\lib\pure\httpclient.nim(1074) getContent                                                           
C:\Nim\lib\pure\httpclient.nim(1069) get                                                                  
C:\Nim\lib\pure\httpclient.nim(1045) request                                                              
C:\Nim\lib\pure\httpclient.nim(1029) request                                                              
C:\Nim\lib\pure\httpclient.nim(1006) requestAux                                                           
C:\Nim\lib\pure\httpclient.nim(814) parseResponse                                                         
C:\Nim\lib\pure\httpcore.nim(158) add                                                                     
SIGSEGV: Illegal storage access. (Attempt to read from nil?)

I tested this with Nim 1.2 and 1.2.2.

[ghost]

I think you have to initialize the Nim GC in the main C app if you're using refc, although I never did that so I don't remember how :P

[zeitbit]

I think you have to initialize the Nim GC in the main C app if you're using refc, although I never did that so I don't remember how :P

It's not necessary to call NimMain directly. The OS calls DllMain when the DLL is loaded with LoadLibrary, and NimMain is called by DllMain:

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fwdreason, 
                    LPVOID lpvReserved) {
	if(fwdreason == DLL_PROCESS_ATTACH) {
	NimMain();
}
	return 1;
}