gistfile1.txt

static VALUE
ole_invoke(int argc, VALUE *argv, VALUE self, USHORT wFlags, BOOL is_bracket)
{
    LCID    lcid = cWIN32OLE_lcid;
    struct oledata *pole;
    HRESULT hr;
    VALUE cmd;
    VALUE paramS;
    VALUE param;
    VALUE obj;
    VALUE v;

    BSTR wcmdname;

    DISPID DispID;
    DISPID* pDispID;
    EXCEPINFO excepinfo;
    VARIANT result;
    VARIANTARG* realargs = NULL;
    unsigned int argErr = 0;
    unsigned int i;
    unsigned int cNamedArgs;
    int n;
    struct oleparam op;
    struct olevariantdata *pvar;
    memset(&excepinfo, 0, sizeof(EXCEPINFO));

    VariantInit(&result);

    op.dp.rgvarg = NULL;
    op.dp.rgdispidNamedArgs = NULL;
    op.dp.cNamedArgs = 0;
    op.dp.cArgs = 0;

    rb_scan_args(argc, argv, "1*", &cmd, &paramS);
    if(TYPE(cmd) != T_STRING && TYPE(cmd) != T_SYMBOL && !is_bracket) {
	rb_raise(rb_eTypeError, "method is wrong type (expected String or Symbol)");
    }
    if (TYPE(cmd) == T_SYMBOL) {
	cmd = rb_sym_to_s(cmd);
    }
    OLEData_Get_Struct(self, pole);
    if(!pole->pDispatch) {
        rb_raise(rb_eRuntimeError, "failed to get dispatch interface");
    }
    if (is_bracket) {
        DispID = DISPID_VALUE;
        argc += 1;
	rb_ary_unshift(paramS, cmd);
    } else {
        wcmdname = ole_vstr2wc(cmd);
        hr = pole->pDispatch->lpVtbl->GetIDsOfNames( pole->pDispatch, &IID_NULL,
                &wcmdname, 1, lcid, &DispID);
        SysFreeString(wcmdname);
        if(FAILED(hr)) {
            ole_raise(hr, eWIN32OLERuntimeError, 
                    "unknown property or method: `%s'",
                    StringValuePtr(cmd));
        }
    }

    /* pick up last argument of method */
    param = rb_ary_entry(paramS, argc-2);

    op.dp.cNamedArgs = 0;

    /* if last arg is hash object */
    if(TYPE(param) == T_HASH) {
        /*------------------------------------------ 
          hash object ==> named dispatch parameters 
        --------------------------------------------*/
        cNamedArgs = NUM2INT(rb_funcall(param, rb_intern("length"), 0));
        op.dp.cArgs = cNamedArgs + argc - 2;
        op.pNamedArgs = ALLOCA_N(OLECHAR*, cNamedArgs + 1);
        op.dp.rgvarg = ALLOCA_N(VARIANTARG, op.dp.cArgs);
        rb_block_call(param, rb_intern("each"), 0, 0, hash2named_arg, (VALUE)&op);

        pDispID = ALLOCA_N(DISPID, cNamedArgs + 1);
        op.pNamedArgs[0] = ole_vstr2wc(cmd);
        hr = pole->pDispatch->lpVtbl->GetIDsOfNames(pole->pDispatch,
                                                    &IID_NULL,
                                                    op.pNamedArgs,
                                                    op.dp.cNamedArgs + 1,
                                                    lcid, pDispID);
        for(i = 0; i < op.dp.cNamedArgs + 1; i++) {
            SysFreeString(op.pNamedArgs[i]);
            op.pNamedArgs[i] = NULL;
        }
        if(FAILED(hr)) {
            /* clear dispatch parameters */
            for(i = 0; i < op.dp.cArgs; i++ ) {
                VariantClear(&op.dp.rgvarg[i]);
            }
            ole_raise(hr, eWIN32OLERuntimeError, 
                      "failed to get named argument info: `%s'",
                      StringValuePtr(cmd));
        }
        op.dp.rgdispidNamedArgs = &(pDispID[1]);
    }
    else {
        cNamedArgs = 0;
        op.dp.cArgs = argc - 1;
        op.pNamedArgs = ALLOCA_N(OLECHAR*, cNamedArgs + 1);
        if (op.dp.cArgs > 0) {
            op.dp.rgvarg  = ALLOCA_N(VARIANTARG, op.dp.cArgs);
        }
    }
    /*--------------------------------------
      non hash args ==> dispatch parameters 
     ----------------------------------------*/
    if(op.dp.cArgs > cNamedArgs) {
        realargs = ALLOCA_N(VARIANTARG, op.dp.cArgs-cNamedArgs+1);
        for(i = cNamedArgs; i < op.dp.cArgs; i++) {
            n = op.dp.cArgs - i + cNamedArgs - 1;
            VariantInit(&realargs[n]);
            VariantInit(&op.dp.rgvarg[n]);
            param = rb_ary_entry(paramS, i-cNamedArgs);
// makes a copy of each parameter OR records a reference to the object
            if (rb_obj_is_kind_of(param, cWIN32OLE_VARIANT)) {
                Data_Get_Struct(param, struct olevariantdata, pvar);
                VariantCopy(&op.dp.rgvarg[n], &(pvar->var));
            } else {
                ole_val2variant(param, &realargs[n]);
                V_VT(&op.dp.rgvarg[n]) = VT_VARIANT | VT_BYREF;
                V_VARIANTREF(&op.dp.rgvarg[n]) = &realargs[n];
            }
        }
    }
    /* apparent you need to call propput, you need this */
    if (wFlags & DISPATCH_PROPERTYPUT) {
        if (op.dp.cArgs == 0)
            ole_raise(ResultFromScode(E_INVALIDARG), eWIN32OLERuntimeError, "argument error");

        op.dp.cNamedArgs = 1;
        op.dp.rgdispidNamedArgs = ALLOCA_N( DISPID, 1 );
        op.dp.rgdispidNamedArgs[0] = DISPID_PROPERTYPUT;
    }
    
    hr = pole->pDispatch->lpVtbl->Invoke(pole->pDispatch, DispID, 
                                         &IID_NULL, lcid, wFlags, &op.dp, 
                                         &result, &excepinfo, &argErr);

    if (FAILED(hr)) {
        /* retry to call args by value */
        if(op.dp.cArgs >= cNamedArgs) {
            for(i = cNamedArgs; i < op.dp.cArgs; i++) {
                n = op.dp.cArgs - i + cNamedArgs - 1;
                param = rb_ary_entry(paramS, i-cNamedArgs);
                ole_val2variant(param, &op.dp.rgvarg[n]);
            }
            if (hr == DISP_E_EXCEPTION) {
                ole_freeexceptinfo(&excepinfo);
            }
            memset(&excepinfo, 0, sizeof(EXCEPINFO));
            VariantInit(&result);
            hr = pole->pDispatch->lpVtbl->Invoke(pole->pDispatch, DispID, 
                                                 &IID_NULL, lcid, wFlags,
                                                 &op.dp, &result,
                                                 &excepinfo, &argErr);

            /* mega kludge. if a method in WORD is called and we ask
             * for a result when one is not returned then
             * hResult == DISP_E_EXCEPTION. this only happens on
             * functions whose DISPID > 0x8000 */
            if ((hr == DISP_E_EXCEPTION || hr == DISP_E_MEMBERNOTFOUND) && DispID > 0x8000) {
                if (hr == DISP_E_EXCEPTION) {
                    ole_freeexceptinfo(&excepinfo);
                }
                memset(&excepinfo, 0, sizeof(EXCEPINFO));
                hr = pole->pDispatch->lpVtbl->Invoke(pole->pDispatch, DispID, 
                        &IID_NULL, lcid, wFlags,
                        &op.dp, NULL,
                        &excepinfo, &argErr);

            }
            for(i = cNamedArgs; i < op.dp.cArgs; i++) {
                n = op.dp.cArgs - i + cNamedArgs - 1;
                VariantClear(&op.dp.rgvarg[n]);
            }
        }

        if (FAILED(hr)) {
            /* retry after converting nil to VT_EMPTY */
            if (op.dp.cArgs > cNamedArgs) {
                for(i = cNamedArgs; i < op.dp.cArgs; i++) {
                    n = op.dp.cArgs - i + cNamedArgs - 1;
                    param = rb_ary_entry(paramS, i-cNamedArgs);
                    ole_val2variant2(param, &op.dp.rgvarg[n]);
                }
                if (hr == DISP_E_EXCEPTION) {
                    ole_freeexceptinfo(&excepinfo);
                }
                memset(&excepinfo, 0, sizeof(EXCEPINFO));
                VariantInit(&result);
                hr = pole->pDispatch->lpVtbl->Invoke(pole->pDispatch, DispID, 
                        &IID_NULL, lcid, wFlags,
                        &op.dp, &result,
                        &excepinfo, &argErr);
                for(i = cNamedArgs; i < op.dp.cArgs; i++) {
                    n = op.dp.cArgs - i + cNamedArgs - 1;
                    VariantClear(&op.dp.rgvarg[n]);
                }
            }
        }

    }
    /* clear dispatch parameter */
    if(op.dp.cArgs > cNamedArgs) {
        for(i = cNamedArgs; i < op.dp.cArgs; i++) {
            n = op.dp.cArgs - i + cNamedArgs - 1;
            param = rb_ary_entry(paramS, i-cNamedArgs);
            if (rb_obj_is_kind_of(param, cWIN32OLE_VARIANT)) {
                ole_val2variant(param, &realargs[n]);
            }
// Why aren't we calling VariantClear() here? Won't this leak the memory allocated to the parameters?
        }
        set_argv(realargs, cNamedArgs, op.dp.cArgs);
    }
    else {
        for(i = 0; i < op.dp.cArgs; i++) {
            VariantClear(&op.dp.rgvarg[i]);
        }
    }

    if (FAILED(hr)) {
        v = ole_excepinfo2msg(&excepinfo);
        ole_raise(hr, eWIN32OLERuntimeError, "(in OLE method `%s': )%s",
                  StringValuePtr(cmd),
                  StringValuePtr(v));
    }
    obj = ole_variant2val(&result);
    VariantClear(&result);
    return obj;
}