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/* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
/*
* Copyright (c) 2008 litl, LLC
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <config.h>
#include "jsapi-util.h"
#include "compat.h"
#include <util/log.h>
#include <string.h>
/*
* See:
* https://bugzilla.mozilla.org/show_bug.cgi?id=166436
* https://bugzilla.mozilla.org/show_bug.cgi?id=215173
*
* Very surprisingly, jsapi.h lacks any way to "throw new Error()"
*
* So here is an awful hack inspired by
* http://egachine.berlios.de/embedding-sm-best-practice/embedding-sm-best-practice.html#error-handling
*/
static void
gjs_throw_valist(JSContext *context,
const char *format,
va_list args)
{
char *s;
jsval retval;
jsval argv[1];
JSFunction *func;
const char *body;
JSBool result;
const char *names[] = { "message" };
guint options;
s = g_strdup_vprintf(format, args);
JS_BeginRequest(context);
if (JS_IsExceptionPending(context)) {
/* Often it's unclear whether a given jsapi.h function
* will throw an exception, so we will throw ourselves
* "just in case"; in those cases, we don't want to
* overwrite an exception that already exists.
* (Do log in case our second exception adds more info,
* but don't log as topic ERROR because if the exception is
* caught we don't want an ERROR in the logs.)
*/
gjs_debug(GJS_DEBUG_CONTEXT,
"Ignoring second exception: '%s'",
s);
g_free(s);
JS_EndRequest(context);
return;
}
result = JS_FALSE;
(void)JS_EnterLocalRootScope(context);
if (!gjs_string_from_utf8(context, s, -1, &argv[0])) {
JS_ReportError(context, "Failed to copy exception string");
goto out;
}
body = "throw new Error(message);";
func = JS_CompileFunction(context,
JS_GetGlobalObject(context), /* parent object (scope chain) */
NULL, /* name of function if we wanted to define it in parent */
1, /* nargs */
&names[0], /* array of arg names if we had args */
body,
strlen(body),
"gjs_throw", /* file */
0); /* line */
if (func == NULL) {
JS_ReportError(context, "Failed to compile function");
goto out;
}
/* we need JS_CallFunctionValue() to leave the exception set */
options = JS_GetOptions(context);
if (!(options & JSOPTION_DONT_REPORT_UNCAUGHT)) {
JS_SetOptions(context, options | JSOPTION_DONT_REPORT_UNCAUGHT);
}
retval = JSVAL_VOID;
/* note the return value is whether function succeeded, which it shouldn't, since it
* throws...
*/
JS_CallFunctionValue(context,
JS_GetGlobalObject(context),
OBJECT_TO_JSVAL(JS_GetFunctionObject(func)),
1, &argv[0],
&retval);
if (!(options & JSOPTION_DONT_REPORT_UNCAUGHT)) {
JS_SetOptions(context, options);
}
if (!JS_IsExceptionPending(context)) {
JS_ReportError(context,
"Failed to set exception by calling our exception-setting function");
goto out;
}
result = JS_TRUE;
out:
JS_LeaveLocalRootScope(context);
if (!result) {
/* try just reporting it to error handler? should not
* happen though pretty much
*/
JS_ReportError(context,
"Failed to throw exception '%s'",
s);
}
g_free(s);
JS_EndRequest(context);
}
/* Throws an exception, like "throw new Error(message)"
*
* If an exception is already set in the context, this will
* NOT overwrite it. That's an important semantic since
* we want the "root cause" exception. To overwrite,
* use JS_ClearPendingException() first.
*/
void
gjs_throw(JSContext *context,
const char *format,
...)
{
va_list args;
va_start(args, format);
gjs_throw_valist(context, format, args);
va_end(args);
}
/**
* gjs_throw_literal:
*
* Similar to gjs_throw(), but does not treat its argument as
* a format string.
*/
void
gjs_throw_literal(JSContext *context,
const char *string)
{
gjs_throw(context, "%s", string);
}
/**
* gjs_throw_g_error:
*
* Convert a GError into a JavaScript Exception, and
* frees the GError. Like gjs_throw(), will not overwrite
* an already pending exception.
*/
void
gjs_throw_g_error (JSContext *context,
GError *error)
{
if (error == NULL)
return;
gjs_throw_literal(context, error->message);
g_error_free (error);
}
#if GJS_BUILD_TESTS
#include "unit-test-utils.h"
void
gjstest_test_func_gjs_jsapi_util_error_throw(void)
{
GjsUnitTestFixture fixture;
JSContext *context;
jsval exc, value, previous;
char *s = NULL;
JSString *str;
int strcmp_result;
_gjs_unit_test_fixture_begin(&fixture);
context = fixture.context;
/* Test that we can throw */
gjs_throw(context, "This is an exception %d", 42);
g_assert(JS_IsExceptionPending(context));
exc = JSVAL_VOID;
JS_GetPendingException(context, &exc);
g_assert(exc != JSVAL_VOID);
value = JSVAL_VOID;
JS_GetProperty(context, JSVAL_TO_OBJECT(exc), "message",
&value);
g_assert(JSVAL_IS_STRING(value));
str = JSVAL_TO_STRING(value);
#ifdef HAVE_JS_GETSTRINGBYTES
/* JS_GetStringBytes() is broken for non-ASCII but that's OK here */
s = g_strdup(JS_GetStringBytes(str));
#else
size_t len = JS_GetStringEncodingLength(context, str);
if (len != (size_t)(-1)) {
s = g_malloc((len + 1) * sizeof(char));
JS_EncodeStringToBuffer(str, s, len);
s[len] = '\0';
}
#endif
g_assert(s != NULL);
strcmp_result = strcmp(s, "This is an exception 42");
free(s);
if (strcmp_result != 0)
g_error("Exception has wrong message '%s'", s);
/* keep this around before we clear it */
previous = exc;
JS_AddValueRoot(context, &previous);
JS_ClearPendingException(context);
g_assert(!JS_IsExceptionPending(context));
/* Check that we don't overwrite a pending exception */
JS_SetPendingException(context, previous);
g_assert(JS_IsExceptionPending(context));
gjs_throw(context, "Second different exception %s", "foo");
g_assert(JS_IsExceptionPending(context));
exc = JSVAL_VOID;
JS_GetPendingException(context, &exc);
g_assert(exc != JSVAL_VOID);
g_assert(exc == previous);
JS_RemoveValueRoot(context, &previous);
_gjs_unit_test_fixture_finish(&fixture);
}
#endif /* GJS_BUILD_TESTS */
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