Replace JS_Enumerate with manual enumeration, to avoid its memory allocations.

Use LookupProperty to avoid having to check for getters.
Add a quicker method of rooting many script values.

This was SVN commit r7579.

source/scriptinterface/AutoRooters.cpp

@@ -0,0 +1,45 @@
+/* Copyright (C) 2010 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 "AutoRooters.h"
+
+#include "scriptinterface/ScriptInterface.h"
+
+AutoGCRooter::AutoGCRooter(ScriptInterface& scriptInterface)
+	: m_ScriptInterface(scriptInterface)
+{
+	m_Previous = m_ScriptInterface.ReplaceAutoGCRooter(this);
+}
+
+AutoGCRooter::~AutoGCRooter()
+{
+	AutoGCRooter* r = m_ScriptInterface.ReplaceAutoGCRooter(m_Previous);
+	debug_assert(r == this); // must be correctly nested
+}
+
+void AutoGCRooter::Trace(JSTracer* trc)
+{
+	if (m_Previous)
+		m_Previous->Trace(trc);
+
+	for (size_t i = 0; i < m_Objects.size(); ++i)
+	{
+		JS_CALL_OBJECT_TRACER(trc, m_Objects[i], "AutoGCRooter object");
+	}
+}

source/scriptinterface/AutoRooters.h

@@ -15,8 +15,13 @@
  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifndef INCLUDED_AUTOROOTERS
+#define INCLUDED_AUTOROOTERS
+
 #include "js/jsapi.h"
 
+class ScriptInterface;
+
 // Exception-safety and GC-safety wrapper for JSIdArray
 // (TODO: it'd be nicer to use the existing js::AutoIdArray but currently that
 // requires a load of semi-private SpiderMonkey headers that cause a load of compile warnings)
@@ -41,3 +46,27 @@ public:
 	}
 };
 
+/**
+ * Helper for rooting large groups of script values.
+ * Construct this object, push values into it, and they will all be rooted until this
+ * object is destroyed.
+ * Many of these objects can be used at once, but their lifetimes must be correctly nested.
+ */
+class AutoGCRooter
+{
+public:
+	AutoGCRooter(ScriptInterface& scriptInterface);
+	~AutoGCRooter();
+
+	void Push(JSObject* obj) { m_Objects.push_back(obj); }
+
+	void Trace(JSTracer* trc);
+private:
+	ScriptInterface& m_ScriptInterface;
+	AutoGCRooter* m_Previous;
+
+	std::vector<JSObject*> m_Objects;
+	// TODO: add vectors of other value types
+};
+
+#endif // INCLUDED_AUTOROOTERS

source/scriptinterface/ScriptInterface.cpp

@@ -59,6 +59,8 @@ struct ScriptInterface_impl
 	JSContext* m_cx;
 	JSObject* m_glob; // global scope object
 	JSObject* m_nativeScope; // native function scope object
+
+	AutoGCRooter* m_rooter;
 };
 
 namespace
@@ -163,7 +165,16 @@ static void* jshook_function(JSContext* cx, JSStackFrame* fp, JSBool before, JSB
 }
 #endif
 
-ScriptInterface_impl::ScriptInterface_impl(const char* nativeScopeName, JSContext* cx)
+void jshook_trace(JSTracer* trc, void* data)
+{
+	ScriptInterface_impl* m = static_cast<ScriptInterface_impl*>(data);
+
+	if (m->m_rooter)
+		m->m_rooter->Trace(trc);
+}
+
+ScriptInterface_impl::ScriptInterface_impl(const char* nativeScopeName, JSContext* cx) :
+	m_rooter(NULL)
 {
 	JSBool ok;
 
@@ -201,6 +212,8 @@ ScriptInterface_impl::ScriptInterface_impl(const char* nativeScopeName, JSContex
 				| JSOPTION_VAROBJFIX // "recommended" (fixes variable scoping)
 		);
 
+		JS_SetExtraGCRoots(m_rt, jshook_trace, this);
+
 		// Threadsafe SpiderMonkey requires that we have a request before doing anything much
 		JS_BeginRequest(m_cx);
 
@@ -296,6 +309,14 @@ bool ScriptInterface::RemoveRoot(void* ptr)
 	return JS_RemoveRoot(m->m_cx, ptr) ? true : false;
 }
 
+AutoGCRooter* ScriptInterface::ReplaceAutoGCRooter(AutoGCRooter* rooter)
+{
+	debug_assert(m->m_rt); // this class must own the runtime, else the rooter won't work
+	AutoGCRooter* ret = m->m_rooter;
+	m->m_rooter = rooter;
+	return ret;
+}
+
 ScriptInterface::LocalRootScope::LocalRootScope(JSContext* cx) :
 	m_cx(cx)
 {

source/scriptinterface/ScriptInterface.h

@@ -29,6 +29,8 @@
 #include "ScriptTypes.h"
 #include "ScriptVal.h"
 
+class AutoGCRooter;
+
 namespace boost { class rand48; }
 
 // Set the maximum number of function arguments that can be handled
@@ -37,7 +39,6 @@ namespace boost { class rand48; }
 #define SCRIPT_INTERFACE_MAX_ARGS 6
 
 struct ScriptInterface_impl;
-class ScriptClass;
 class ScriptInterface
 {
 public:
@@ -181,6 +182,8 @@ public:
 	bool AddRoot(void* ptr, const char* name);
 	bool RemoveRoot(void* ptr);
 
+	AutoGCRooter* ReplaceAutoGCRooter(AutoGCRooter* rooter);
+
 	/**
 	 * Dump some memory heap debugging information to stderr.
 	 */