Improve JS Exception handling.

- Check for pending exceptions after function calls and script executions. - Call LOGERROR instead of JS_ReportError when there is a conversion error in FromJSVal, since that can only be called from C++ (where JS errors don't really make sense). Instead, C++ callers of FromJSVal should handle the failure and, themselves, either report an error or simply do something else. - Wrap JS_ReportError since that makes updating it later easier. This isn't a systematical fix since ToJSVal also ought return a boolean for failures, and we probably should trigger errors instead of warnings on 'implicit' conversions, rather a preparation diff. Part of the SM52 migration, stage: SM45 compatible (actually SM52 incompatible, too). Based on a patch by: Itms Comments by: Vladislavbelov, Stan` Refs #742, #4893 Differential Revision: https://code.wildfiregames.com/D3093 This was SVN commit r24187.
2026-06-21 22:24:19 +00:00 · 2020-11-15 18:29:17 +00:00
parent 88bc973530
commit 25490bfec3
79 changed files with 810 additions and 667 deletions
@@ -0,0 +1,151 @@
+/* Copyright (C) 2020 Wildfire Games.
+ * This file is part of 0 A.D.
+ *
+ * 0 A.D. is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 0 A.D. is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include "precompiled.h"
+
+#include "ScriptExceptions.h"
+
+#include "ps/CLogger.h"
+#include "scriptinterface/ScriptInterface.h"
+
+bool ScriptException::IsPending(const ScriptRequest& rq)
+{
+	return JS_IsExceptionPending(rq.cx);
+}
+
+bool ScriptException::CatchPending(const ScriptRequest& rq)
+{
+	if (!JS_IsExceptionPending(rq.cx))
+		return false;
+
+	JS::RootedValue excn(rq.cx);
+	ENSURE(JS_GetPendingException(rq.cx, &excn));
+
+	if (excn.isUndefined())
+	{
+		LOGERROR("JavaScript error: (undefined)");
+		JS_ClearPendingException(rq.cx);
+		return true;
+	}
+
+	// As of SM45/52, there is no way to recover a stack in case the thrown thing is not an Error object.
+	if (!excn.isObject())
+	{
+		CStr error;
+		ScriptInterface::FromJSVal(rq, excn, error);
+		LOGERROR("JavaScript error: %s", error);
+		JS_ClearPendingException(rq.cx);
+		return true;
+	}
+
+	JS::RootedObject excnObj(rq.cx, &excn.toObject());
+	JSErrorReport* report = JS_ErrorFromException(rq.cx, excnObj);
+
+	if (!report)
+	{
+		CStr error;
+		ScriptInterface::FromJSVal(rq, excn, error);
+		LOGERROR("JavaScript error: %s", error);
+		JS_ClearPendingException(rq.cx);
+		return true;
+	}
+
+	std::stringstream msg;
+	msg << (JSREPORT_IS_EXCEPTION(report->flags) ? "JavaScript exception: " : "JavaScript error: ");
+	if (report->filename)
+	{
+		msg << report->filename;
+		msg << " line " << report->lineno << "\n";
+	}
+
+	// TODO SM52:
+	// msg << report->message();
+
+	JS::RootedObject stackObj(rq.cx, ExceptionStackOrNull(rq.cx, excnObj));
+	JS::RootedValue stackVal(rq.cx, JS::ObjectOrNullValue(stackObj));
+	if (!stackVal.isNull())
+	{
+		std::string stackText;
+		ScriptInterface::FromJSVal(rq, stackVal, stackText);
+
+		std::istringstream stream(stackText);
+		for (std::string line; std::getline(stream, line);)
+			msg << "\n  " << line;
+	}
+
+	LOGERROR("%s", msg.str().c_str());
+
+	// When running under Valgrind, print more information in the error message
+	//	VALGRIND_PRINTF_BACKTRACE("->");
+
+	JS_ClearPendingException(rq.cx);
+	return true;
+}
+
+void ScriptException::ErrorReporter(JSContext* cx, const char* message, JSErrorReport* report)
+{
+	if (!ScriptInterface::GetScriptInterfaceAndCBData(cx))
+	{
+		LOGERROR("Javascript - Out of Memory error");
+		return;
+	}
+	ScriptRequest rq(*ScriptInterface::GetScriptInterfaceAndCBData(cx)->pScriptInterface);
+
+	std::stringstream msg;
+	bool isWarning = JSREPORT_IS_WARNING(report->flags);
+	msg << (isWarning ? "JavaScript warning: " : "JavaScript error: ");
+	if (report->filename)
+	{
+		msg << report->filename;
+		msg << " line " << report->lineno << "\n";
+	}
+
+	msg << message;
+
+	// If there is an exception, then print its stack trace
+	JS::RootedValue excn(rq.cx);
+	if (JS_GetPendingException(rq.cx, &excn) && excn.isObject())
+	{
+		JS::RootedValue stackVal(rq.cx);
+		JS::RootedObject excnObj(rq.cx, &excn.toObject());
+		JS_GetProperty(rq.cx, excnObj, "stack", &stackVal);
+
+		std::string stackText;
+		ScriptInterface::FromJSVal(rq, stackVal, stackText);
+
+		std::istringstream stream(stackText);
+		for (std::string line; std::getline(stream, line);)
+			msg << "\n  " << line;
+	}
+
+	if (isWarning)
+		LOGWARNING("%s", msg.str().c_str());
+	else
+		LOGERROR("%s", msg.str().c_str());
+
+	// When running under Valgrind, print more information in the error message
+	//	VALGRIND_PRINTF_BACKTRACE("->");
+}
+
+void ScriptException::Raise(const ScriptRequest& rq, const char* format, ...)
+{
+	va_list ap;
+	va_start(ap, format);
+	JS_ReportError(rq.cx, format, ap);
+	va_end(ap);
+}