/* src/common/backend/port/dynloader/win32.c */

#include "postgres.h"
#include "knl/knl_variable.h"
#include "securec.h"

char* dlerror(void);
int dlclose(void* handle);
void* dlsym(void* handle, const char* symbol);
void* dlopen(const char* path, int mode);

static char last_dyn_error[512];

static void set_dl_error(void)
{
    DWORD err = GetLastError();
    if (FormatMessage(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
        NULL,
        err,
        MAKELANGID(LANG_ENGLISH, SUBLANG_DEFAULT),
        last_dyn_error,
        sizeof(last_dyn_error) - 1,
        NULL) == 0) {
        int rc = snprintf_truncated_s(last_dyn_error, sizeof(last_dyn_error), "unknown error %lu", err);
        securec_check_ss(rc, "\0", "\0");
    }
}

char* dlerror(void)
{
    if (last_dyn_error[0]) {
        return last_dyn_error;
    } else {
        return NULL;
    }
}

int dlclose(void* handle)
{
    if (!FreeLibrary((HMODULE)handle)) {
        set_dl_error();
        return 1;
    }
    last_dyn_error[0] = 0;
    return 0;
}

void* dlsym(void* handle, const char* symbol)
{
    void* ptr = NULL;

    ptr = GetProcAddress((HMODULE)handle, symbol);
    if (ptr == NULL) {
        set_dl_error();
        return NULL;
    }
    last_dyn_error[0] = 0;
    return ptr;
}

void* dlopen(const char* path, int mode)
{
    HMODULE h;
    int prevmode;

    /* Disable popup error messages when loading DLLs */
    prevmode = SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX);
    h = LoadLibrary(path);
    SetErrorMode(prevmode);

    if (!h) {
        set_dl_error();
        return NULL;
    }
    last_dyn_error[0] = 0;
    return (void*)h;
}