0ad/source/scriptinterface/ScriptConversions.h
wraitii ee0d204bf6 Wrap JSAutoRequest and replace usage of JSContext* with the wrapper.
JSAutoRequest is required before calling into most JSAPI methods, for GC
reasons.
Calling it is required and fragile as one must not forget.
Further, SM52 and later make manipulating JSContext* dangerous as that
can cross Compartment(Realm in SM68) barriers (and ScriptInterface now
matches a Compartment).

The solution to both problems is to avoid using JSContext* in 0 A.D.
itself. To achieve this, a Request class is introduced, and must be used
to access a JSContext* from a scriptInterface. Further, Request is
passed to other ScriptInterface functions isntead of JSContext*, making
it obvious that the caller has already called it, reducing errors and
redundant JSAutoRequest calls.
Only JSNative functions now get a naked JSContext* without protection,
but the likelihood of forgetting a request is lower since many
ScriptInterface functions now expect it.

JSContext* is directly passed to JSAPI functions only.

Part of the SM52 migration, stage: SM45 compatible

Based on a patch by: Itms
Tested By: Freagarach
Refs #4893

Differential Revision: https://code.wildfiregames.com/D3088
This was SVN commit r24176.
2020-11-13 13:18:22 +00:00

109 lines
3.1 KiB
C++

/* 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/>.
*/
#ifndef INCLUDED_SCRIPTCONVERSIONS
#define INCLUDED_SCRIPTCONVERSIONS
#include "ScriptInterface.h"
#include "scriptinterface/ScriptExtraHeaders.h" // for typed arrays
#include <limits>
template<typename T> static void ToJSVal_vector(const ScriptInterface::Request& rq, JS::MutableHandleValue ret, const std::vector<T>& val)
{
JS::RootedObject obj(rq.cx, JS_NewArrayObject(rq.cx, 0));
if (!obj)
{
ret.setUndefined();
return;
}
ENSURE(val.size() <= std::numeric_limits<u32>::max());
for (u32 i = 0; i < val.size(); ++i)
{
JS::RootedValue el(rq.cx);
ScriptInterface::ToJSVal<T>(rq, &el, val[i]);
JS_SetElement(rq.cx, obj, i, el);
}
ret.setObject(*obj);
}
#define FAIL(msg) STMT(JS_ReportError(rq.cx, msg); return false)
template<typename T> static bool FromJSVal_vector(const ScriptInterface::Request& rq, JS::HandleValue v, std::vector<T>& out)
{
JS::RootedObject obj(rq.cx);
if (!v.isObject())
FAIL("Argument must be an array");
bool isArray;
obj = &v.toObject();
if ((!JS_IsArrayObject(rq.cx, obj, &isArray) || !isArray) && !JS_IsTypedArrayObject(obj))
FAIL("Argument must be an array");
u32 length;
if (!JS_GetArrayLength(rq.cx, obj, &length))
FAIL("Failed to get array length");
out.reserve(length);
for (u32 i = 0; i < length; ++i)
{
JS::RootedValue el(rq.cx);
if (!JS_GetElement(rq.cx, obj, i, &el))
FAIL("Failed to read array element");
T el2;
if (!ScriptInterface::FromJSVal<T>(rq, el, el2))
return false;
out.push_back(el2);
}
return true;
}
#undef FAIL
#define JSVAL_VECTOR(T) \
template<> void ScriptInterface::ToJSVal<std::vector<T> >(const ScriptInterface::Request& rq, JS::MutableHandleValue ret, const std::vector<T>& val) \
{ \
ToJSVal_vector(rq, ret, val); \
} \
template<> bool ScriptInterface::FromJSVal<std::vector<T> >(const ScriptInterface::Request& rq, JS::HandleValue v, std::vector<T>& out) \
{ \
return FromJSVal_vector(rq, v, out); \
}
template<typename T> bool ScriptInterface::FromJSProperty(const ScriptInterface::Request& rq, const JS::HandleValue val, const char* name, T& ret, bool strict)
{
if (!val.isObject())
return false;
JS::RootedObject obj(rq.cx, &val.toObject());
bool hasProperty;
if (!JS_HasProperty(rq.cx, obj, name, &hasProperty) || !hasProperty)
return false;
JS::RootedValue value(rq.cx);
if (!JS_GetProperty(rq.cx, obj, name, &value))
return false;
if (strict && value.isNull())
return false;
return FromJSVal(rq, value, ret);
}
#endif //INCLUDED_SCRIPTCONVERSIONS