0ad/source/simulation2/scripting/ScriptComponent.cpp
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

119 lines
3.9 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/>.
*/
#include "precompiled.h"
#include "ScriptComponent.h"
#include "simulation2/serialization/ISerializer.h"
#include "simulation2/serialization/IDeserializer.h"
CComponentTypeScript::CComponentTypeScript(const ScriptInterface& scriptInterface, JS::HandleValue instance) :
m_ScriptInterface(scriptInterface), m_Instance(scriptInterface.GetJSRuntime(), instance)
{
// Cache the property detection for efficiency
ScriptInterface::Request rq(m_ScriptInterface);
m_HasCustomSerialize = m_ScriptInterface.HasProperty(m_Instance, "Serialize");
m_HasCustomDeserialize = m_ScriptInterface.HasProperty(m_Instance, "Deserialize");
m_HasNullSerialize = false;
if (m_HasCustomSerialize)
{
JS::RootedValue val(rq.cx);
if (m_ScriptInterface.GetProperty(m_Instance, "Serialize", &val) && val.isNull())
m_HasNullSerialize = true;
}
}
void CComponentTypeScript::Init(const CParamNode& paramNode, entity_id_t ent)
{
m_ScriptInterface.SetProperty(m_Instance, "entity", (int)ent, true, false);
m_ScriptInterface.SetProperty(m_Instance, "template", paramNode, true, false);
m_ScriptInterface.CallFunctionVoid(m_Instance, "Init");
}
void CComponentTypeScript::Deinit()
{
m_ScriptInterface.CallFunctionVoid(m_Instance, "Deinit");
}
void CComponentTypeScript::HandleMessage(const CMessage& msg, bool global)
{
ScriptInterface::Request rq(m_ScriptInterface);
const char* name = global ? msg.GetScriptGlobalHandlerName() : msg.GetScriptHandlerName();
JS::RootedValue msgVal(rq.cx, msg.ToJSValCached(m_ScriptInterface));
if (!m_ScriptInterface.CallFunctionVoid(m_Instance, name, msgVal))
LOGERROR("Script message handler %s failed", name);
}
void CComponentTypeScript::Serialize(ISerializer& serialize)
{
// If the component set Serialize = null, then do no work here
if (m_HasNullSerialize)
return;
ScriptInterface::Request rq(m_ScriptInterface);
// Support a custom "Serialize" function, which returns a new object that will be
// serialized instead of the component itself
if (m_HasCustomSerialize)
{
JS::RootedValue val(rq.cx);
if (!m_ScriptInterface.CallFunction(m_Instance, "Serialize", &val))
LOGERROR("Script Serialize call failed");
serialize.ScriptVal("object", &val);
}
else
{
serialize.ScriptVal("object", &m_Instance);
}
}
void CComponentTypeScript::Deserialize(const CParamNode& paramNode, IDeserializer& deserialize, entity_id_t ent)
{
ScriptInterface::Request rq(m_ScriptInterface);
m_ScriptInterface.SetProperty(m_Instance, "entity", (int)ent, true, false);
m_ScriptInterface.SetProperty(m_Instance, "template", paramNode, true, false);
// Support a custom "Deserialize" function, to which we pass the deserialized data
// instead of automatically adding the deserialized properties onto the object
if (m_HasCustomDeserialize)
{
JS::RootedValue val(rq.cx);
// If Serialize = null, we'll still call Deserialize but with undefined argument
if (!m_HasNullSerialize)
deserialize.ScriptVal("object", &val);
if (!m_ScriptInterface.CallFunctionVoid(m_Instance, "Deserialize", val))
LOGERROR("Script Deserialize call failed");
}
else
{
if (!m_HasNullSerialize)
{
// Use ScriptObjectAppend so we don't lose the carefully-constructed
// prototype/parent of this object
deserialize.ScriptObjectAppend("object", m_Instance);
}
}
}