/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Chris Waterson <waterson@netscape.com>
 *   L. David Baron <dbaron@dbaron.org>
 *   Ben Goodger <ben@netscape.com>
 *   Mark Hammond <mhammond@skippinet.com.au>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */


#include "nsXULPrototypeDocument.h"
#include "nsXULDocument.h"

#include "nsAString.h"
#include "nsIObjectInputStream.h"
#include "nsIObjectOutputStream.h"
#include "nsIPrincipal.h"
#include "nsIScriptGlobalObject.h"
#include "nsIScriptObjectPrincipal.h"
#include "nsIScriptSecurityManager.h"
#include "nsIScriptRuntime.h"
#include "nsIServiceManager.h"
#include "nsIArray.h"
#include "nsIURI.h"
#include "jsapi.h"
#include "nsString.h"
#include "nsIConsoleService.h"
#include "nsIScriptError.h"
#include "mozilla/FunctionTimer.h"
#include "nsIDOMScriptObjectFactory.h"
#include "nsDOMCID.h"
#include "nsNodeInfoManager.h"
#include "nsContentUtils.h"
#include "nsCCUncollectableMarker.h"
#include "nsDOMJSUtils.h" // for GetScriptContextFromJSContext
#include "xpcpublic.h"

static NS_DEFINE_CID(kDOMScriptObjectFactoryCID,
                     NS_DOM_SCRIPT_OBJECT_FACTORY_CID);


class nsXULPDGlobalObject : public nsIScriptGlobalObject,
                            public nsIScriptObjectPrincipal
{
public:
    nsXULPDGlobalObject(nsXULPrototypeDocument* owner);

    // nsISupports interface
    NS_DECL_CYCLE_COLLECTING_ISUPPORTS

    // nsIScriptGlobalObject methods
    virtual void OnFinalize(JSObject* aObject);
    virtual void SetScriptsEnabled(bool aEnabled, bool aFireTimeouts);

    virtual JSObject* GetGlobalJSObject();
    virtual nsresult EnsureScriptEnvironment(PRUint32 aLangID);

    virtual nsIScriptContext *GetScriptContext(PRUint32 lang);
    virtual nsresult SetScriptContext(PRUint32 language, nsIScriptContext *ctx);

    // nsIScriptObjectPrincipal methods
    virtual nsIPrincipal* GetPrincipal();

    NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsXULPDGlobalObject,
                                             nsIScriptGlobalObject)

    void ClearGlobalObjectOwner();

protected:
    virtual ~nsXULPDGlobalObject();

    nsXULPrototypeDocument* mGlobalObjectOwner; // weak reference

    nsCOMPtr<nsIScriptContext> mContext;
    JSObject* mJSObject;

    nsCOMPtr<nsIPrincipal> mCachedPrincipal;

    static JSClass gSharedGlobalClass;
};

nsIPrincipal* nsXULPrototypeDocument::gSystemPrincipal;
nsXULPDGlobalObject* nsXULPrototypeDocument::gSystemGlobal;
PRUint32 nsXULPrototypeDocument::gRefCnt;


void
nsXULPDGlobalObject_finalize(JSContext *cx, JSObject *obj)
{
    nsISupports *nativeThis = (nsISupports*)JS_GetPrivate(obj);

    nsCOMPtr<nsIScriptGlobalObject> sgo(do_QueryInterface(nativeThis));

    if (sgo) {
        sgo->OnFinalize(obj);
    }

    // The addref was part of JSObject construction
    NS_RELEASE(nativeThis);
}


JSBool
nsXULPDGlobalObject_resolve(JSContext *cx, JSObject *obj, jsid id)
{
    JSBool did_resolve = JS_FALSE;

    return JS_ResolveStandardClass(cx, obj, id, &did_resolve);
}


JSClass nsXULPDGlobalObject::gSharedGlobalClass = {
    "nsXULPrototypeScript compilation scope",
    XPCONNECT_GLOBAL_FLAGS,
    JS_PropertyStub,  JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
    JS_EnumerateStub, nsXULPDGlobalObject_resolve,  JS_ConvertStub,
    nsXULPDGlobalObject_finalize, NULL, NULL, NULL, NULL,
    TraceXPCGlobal
};



//----------------------------------------------------------------------
//
// ctors, dtors, n' stuff
//

nsXULPrototypeDocument::nsXULPrototypeDocument()
    : mRoot(nsnull),
      mLoaded(false),
      mCCGeneration(0)
{
    ++gRefCnt;
}


nsresult
nsXULPrototypeDocument::Init()
{
    mNodeInfoManager = new nsNodeInfoManager();
    NS_ENSURE_TRUE(mNodeInfoManager, NS_ERROR_OUT_OF_MEMORY);

    return mNodeInfoManager->Init(nsnull);
}

nsXULPrototypeDocument::~nsXULPrototypeDocument()
{
    if (mGlobalObject) {
        // cleaup cycles etc.
        mGlobalObject->ClearGlobalObjectOwner();
    }

    if (mRoot)
        mRoot->ReleaseSubtree();

    if (--gRefCnt == 0) {
        NS_IF_RELEASE(gSystemPrincipal);
        NS_IF_RELEASE(gSystemGlobal);
    }
}

NS_IMPL_CYCLE_COLLECTION_CLASS(nsXULPrototypeDocument)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsXULPrototypeDocument)
    tmp->mPrototypeWaiters.Clear();
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsXULPrototypeDocument)
    if (nsCCUncollectableMarker::InGeneration(cb, tmp->mCCGeneration)) {
        return NS_SUCCESS_INTERRUPTED_TRAVERSE;
    }
    NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mRoot)
    NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mGlobalObject");
    cb.NoteXPCOMChild(static_cast<nsIScriptGlobalObject*>(tmp->mGlobalObject));
    NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NATIVE_MEMBER(mNodeInfoManager,
                                                    nsNodeInfoManager)
    for (PRUint32 i = 0; i < tmp->mPrototypeWaiters.Length(); ++i) {
        NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mPrototypeWaiters[i]");
        cb.NoteXPCOMChild(static_cast<nsINode*>(tmp->mPrototypeWaiters[i].get()));
    }
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsXULPrototypeDocument)
    NS_INTERFACE_MAP_ENTRY(nsIScriptGlobalObjectOwner)
    NS_INTERFACE_MAP_ENTRY(nsISerializable)
    NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIScriptGlobalObjectOwner)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(nsXULPrototypeDocument)
NS_IMPL_CYCLE_COLLECTING_RELEASE(nsXULPrototypeDocument)

NS_IMETHODIMP
NS_NewXULPrototypeDocument(nsXULPrototypeDocument** aResult)
{
    *aResult = new nsXULPrototypeDocument();
    if (! *aResult)
        return NS_ERROR_OUT_OF_MEMORY;

    nsresult rv;
    rv = (*aResult)->Init();
    if (NS_FAILED(rv)) {
        delete *aResult;
        *aResult = nsnull;
        return rv;
    }

    NS_ADDREF(*aResult);
    return rv;
}

// Helper method that shares a system global among all prototype documents
// that have the system principal as their security principal.   Called by
// nsXULPrototypeDocument::Read and
// nsXULPrototypeDocument::GetScriptGlobalObject.
// This method greatly reduces the number of nsXULPDGlobalObjects and their
// nsIScriptContexts in apps that load many XUL documents via chrome: URLs.

nsXULPDGlobalObject *
nsXULPrototypeDocument::NewXULPDGlobalObject()
{
    // Now compare DocumentPrincipal() to gSystemPrincipal, in order to create
    // gSystemGlobal if the two pointers are equal.  Thus, gSystemGlobal
    // implies gSystemPrincipal.
    nsXULPDGlobalObject *global;
    if (DocumentPrincipal() == gSystemPrincipal) {
        if (!gSystemGlobal) {
            gSystemGlobal = new nsXULPDGlobalObject(nsnull);
            if (! gSystemGlobal)
                return nsnull;
            NS_ADDREF(gSystemGlobal);
        }
        global = gSystemGlobal;
    } else {
        global = new nsXULPDGlobalObject(this); // does not refcount
        if (! global)
            return nsnull;
    }
    return global;
}

//----------------------------------------------------------------------
//
// nsISerializable methods
//

NS_IMETHODIMP
nsXULPrototypeDocument::Read(nsIObjectInputStream* aStream)
{
    NS_TIME_FUNCTION;
    nsresult rv;

    rv = aStream->ReadObject(true, getter_AddRefs(mURI));

    PRUint32 count, i;
    nsCOMPtr<nsIURI> styleOverlayURI;

    rv |= aStream->Read32(&count);
    if (NS_FAILED(rv)) return rv;

    for (i = 0; i < count; ++i) {
        rv |= aStream->ReadObject(true, getter_AddRefs(styleOverlayURI));
        mStyleSheetReferences.AppendObject(styleOverlayURI);
    }


    // nsIPrincipal mNodeInfoManager->mPrincipal
    nsCOMPtr<nsIPrincipal> principal;
    rv |= aStream->ReadObject(true, getter_AddRefs(principal));
    // Better safe than sorry....
    mNodeInfoManager->SetDocumentPrincipal(principal);


    // nsIScriptGlobalObject mGlobalObject
    mGlobalObject = NewXULPDGlobalObject();
    if (! mGlobalObject)
        return NS_ERROR_OUT_OF_MEMORY;

    mRoot = new nsXULPrototypeElement();
    if (! mRoot)
       return NS_ERROR_OUT_OF_MEMORY;

    // nsINodeInfo table
    nsCOMArray<nsINodeInfo> nodeInfos;

    rv |= aStream->Read32(&count);
    nsAutoString namespaceURI, prefixStr, localName;
    bool prefixIsNull;
    nsCOMPtr<nsIAtom> prefix;
    for (i = 0; i < count; ++i) {
        rv |= aStream->ReadString(namespaceURI);
        rv |= aStream->ReadBoolean(&prefixIsNull);
        if (prefixIsNull) {
            prefix = nsnull;
        } else {
            rv |= aStream->ReadString(prefixStr);
            prefix = do_GetAtom(prefixStr);
        }
        rv |= aStream->ReadString(localName);

        nsCOMPtr<nsINodeInfo> nodeInfo;
        // Using PR_UINT16_MAX here as we don't know which nodeinfos will be
        // used for attributes and which for elements. And that doesn't really
        // matter.
        rv |= mNodeInfoManager->GetNodeInfo(localName, prefix, namespaceURI,
                                            PR_UINT16_MAX,
                                            getter_AddRefs(nodeInfo));
        if (!nodeInfos.AppendObject(nodeInfo))
            rv |= NS_ERROR_OUT_OF_MEMORY;
    }

    // Document contents
    PRUint32 type;
    while (NS_SUCCEEDED(rv)) {
        rv |= aStream->Read32(&type);

        if ((nsXULPrototypeNode::Type)type == nsXULPrototypeNode::eType_PI) {
            nsRefPtr<nsXULPrototypePI> pi = new nsXULPrototypePI();
            if (! pi) {
               rv |= NS_ERROR_OUT_OF_MEMORY;
               break;
            }

            rv |= pi->Deserialize(aStream, mGlobalObject, mURI, &nodeInfos);
            rv |= AddProcessingInstruction(pi);
        } else if ((nsXULPrototypeNode::Type)type == nsXULPrototypeNode::eType_Element) {
            rv |= mRoot->Deserialize(aStream, mGlobalObject, mURI, &nodeInfos);
            break;
        } else {
            NS_NOTREACHED("Unexpected prototype node type");
            rv |= NS_ERROR_FAILURE;
            break;
        }
    }
    rv |= NotifyLoadDone();

    return rv;
}

static nsresult
GetNodeInfos(nsXULPrototypeElement* aPrototype,
             nsCOMArray<nsINodeInfo>& aArray)
{
    nsresult rv;
    if (aArray.IndexOf(aPrototype->mNodeInfo) < 0) {
        if (!aArray.AppendObject(aPrototype->mNodeInfo)) {
            return NS_ERROR_OUT_OF_MEMORY;
        }
    }

    // Search attributes
    PRUint32 i;
    for (i = 0; i < aPrototype->mNumAttributes; ++i) {
        nsCOMPtr<nsINodeInfo> ni;
        nsAttrName* name = &aPrototype->mAttributes[i].mName;
        if (name->IsAtom()) {
            ni = aPrototype->mNodeInfo->NodeInfoManager()->
                GetNodeInfo(name->Atom(), nsnull, kNameSpaceID_None,
                            nsIDOMNode::ATTRIBUTE_NODE);
            NS_ENSURE_TRUE(ni, NS_ERROR_OUT_OF_MEMORY);
        }
        else {
            ni = name->NodeInfo();
        }

        if (aArray.IndexOf(ni) < 0) {
            if (!aArray.AppendObject(ni)) {
                return NS_ERROR_OUT_OF_MEMORY;
            }
        }
    }

    // Search children
    for (i = 0; i < aPrototype->mChildren.Length(); ++i) {
        nsXULPrototypeNode* child = aPrototype->mChildren[i];
        if (child->mType == nsXULPrototypeNode::eType_Element) {
            rv = GetNodeInfos(static_cast<nsXULPrototypeElement*>(child),
                              aArray);
            NS_ENSURE_SUCCESS(rv, rv);
        }
    }

    return NS_OK;
}

NS_IMETHODIMP
nsXULPrototypeDocument::Write(nsIObjectOutputStream* aStream)
{
    nsresult rv;

    rv = aStream->WriteCompoundObject(mURI, NS_GET_IID(nsIURI), true);
    
    PRUint32 count;

    count = mStyleSheetReferences.Count();
    rv |= aStream->Write32(count);

    PRUint32 i;
    for (i = 0; i < count; ++i) {
        rv |= aStream->WriteCompoundObject(mStyleSheetReferences[i],
                                           NS_GET_IID(nsIURI), true);
    }

    // nsIPrincipal mNodeInfoManager->mPrincipal
    rv |= aStream->WriteObject(mNodeInfoManager->DocumentPrincipal(),
                               true);
    
#ifdef DEBUG
    // XXX Worrisome if we're caching things without system principal.
    if (!nsContentUtils::IsSystemPrincipal(mNodeInfoManager->DocumentPrincipal())) {
        NS_WARNING("Serializing document without system principal");
    }
#endif

    // nsINodeInfo table
    nsCOMArray<nsINodeInfo> nodeInfos;
    if (mRoot)
        rv |= GetNodeInfos(mRoot, nodeInfos);

    PRUint32 nodeInfoCount = nodeInfos.Count();
    rv |= aStream->Write32(nodeInfoCount);
    for (i = 0; i < nodeInfoCount; ++i) {
        nsINodeInfo *nodeInfo = nodeInfos[i];
        NS_ENSURE_TRUE(nodeInfo, NS_ERROR_FAILURE);

        nsAutoString namespaceURI;
        rv |= nodeInfo->GetNamespaceURI(namespaceURI);
        rv |= aStream->WriteWStringZ(namespaceURI.get());

        nsAutoString prefix;
        nodeInfo->GetPrefix(prefix);
        bool nullPrefix = DOMStringIsNull(prefix);
        rv |= aStream->WriteBoolean(nullPrefix);
        if (!nullPrefix) {
            rv |= aStream->WriteWStringZ(prefix.get());
        }

        nsAutoString localName;
        nodeInfo->GetName(localName);
        rv |= aStream->WriteWStringZ(localName.get());
    }

    // Now serialize the document contents
    nsIScriptGlobalObject* globalObject = GetScriptGlobalObject();
    NS_ENSURE_TRUE(globalObject, NS_ERROR_UNEXPECTED);

    count = mProcessingInstructions.Length();
    for (i = 0; i < count; ++i) {
        nsXULPrototypePI* pi = mProcessingInstructions[i];
        rv |= pi->Serialize(aStream, globalObject, &nodeInfos);
    }

    if (mRoot)
        rv |= mRoot->Serialize(aStream, globalObject, &nodeInfos);
 
    return rv;
}


//----------------------------------------------------------------------
//

nsresult
nsXULPrototypeDocument::InitPrincipal(nsIURI* aURI, nsIPrincipal* aPrincipal)
{
    NS_ENSURE_ARG_POINTER(aURI);

    mURI = aURI;
    mNodeInfoManager->SetDocumentPrincipal(aPrincipal);
    return NS_OK;
}
    

nsIURI*
nsXULPrototypeDocument::GetURI()
{
    NS_ASSERTION(mURI, "null URI");
    return mURI;
}


nsXULPrototypeElement*
nsXULPrototypeDocument::GetRootElement()
{
    return mRoot;
}


void
nsXULPrototypeDocument::SetRootElement(nsXULPrototypeElement* aElement)
{
    mRoot = aElement;
}

nsresult
nsXULPrototypeDocument::AddProcessingInstruction(nsXULPrototypePI* aPI)
{
    NS_PRECONDITION(aPI, "null ptr");
    if (!mProcessingInstructions.AppendElement(aPI)) {
        return NS_ERROR_OUT_OF_MEMORY;
    }
    return NS_OK;
}

const nsTArray<nsRefPtr<nsXULPrototypePI> >&
nsXULPrototypeDocument::GetProcessingInstructions() const
{
    return mProcessingInstructions;
}

void
nsXULPrototypeDocument::AddStyleSheetReference(nsIURI* aURI)
{
    NS_PRECONDITION(aURI, "null ptr");
    if (!mStyleSheetReferences.AppendObject(aURI)) {
        NS_WARNING("mStyleSheetReferences->AppendElement() failed."
                   "Stylesheet overlay dropped.");
    }
}

const nsCOMArray<nsIURI>&
nsXULPrototypeDocument::GetStyleSheetReferences() const
{
    return mStyleSheetReferences;
}

NS_IMETHODIMP
nsXULPrototypeDocument::GetHeaderData(nsIAtom* aField, nsAString& aData) const
{
    // XXX Not implemented
    aData.Truncate();
    return NS_OK;
}


NS_IMETHODIMP
nsXULPrototypeDocument::SetHeaderData(nsIAtom* aField, const nsAString& aData)
{
    // XXX Not implemented
    return NS_OK;
}



nsIPrincipal*
nsXULPrototypeDocument::DocumentPrincipal()
{
    NS_PRECONDITION(mNodeInfoManager, "missing nodeInfoManager");
    return mNodeInfoManager->DocumentPrincipal();
}

void
nsXULPrototypeDocument::SetDocumentPrincipal(nsIPrincipal* aPrincipal)
{
    mNodeInfoManager->SetDocumentPrincipal(aPrincipal);
}

nsNodeInfoManager*
nsXULPrototypeDocument::GetNodeInfoManager()
{
    return mNodeInfoManager;
}


nsresult
nsXULPrototypeDocument::AwaitLoadDone(nsXULDocument* aDocument, bool* aResult)
{
    nsresult rv = NS_OK;

    *aResult = mLoaded;

    if (!mLoaded) {
        rv = mPrototypeWaiters.AppendElement(aDocument)
              ? NS_OK : NS_ERROR_OUT_OF_MEMORY; // addrefs
    }

    return rv;
}


nsresult
nsXULPrototypeDocument::NotifyLoadDone()
{
    // Call back to each XUL document that raced to start the same
    // prototype document load, lost the race, but hit the XUL
    // prototype cache because the winner filled the cache with
    // the not-yet-loaded prototype object.

    nsresult rv = NS_OK;

    mLoaded = true;

    for (PRUint32 i = mPrototypeWaiters.Length(); i > 0; ) {
        --i;
        // true means that OnPrototypeLoadDone will also
        // call ResumeWalk().
        rv = mPrototypeWaiters[i]->OnPrototypeLoadDone(true);
        if (NS_FAILED(rv)) break;
    }
    mPrototypeWaiters.Clear();

    return rv;
}

//----------------------------------------------------------------------
//
// nsIScriptGlobalObjectOwner methods
//

nsIScriptGlobalObject*
nsXULPrototypeDocument::GetScriptGlobalObject()
{
    if (!mGlobalObject)
        mGlobalObject = NewXULPDGlobalObject();

    return mGlobalObject;
}

//----------------------------------------------------------------------
//
// nsXULPDGlobalObject
//

nsXULPDGlobalObject::nsXULPDGlobalObject(nsXULPrototypeDocument* owner)
  : mGlobalObjectOwner(owner)
  , mJSObject(NULL)
{
}


nsXULPDGlobalObject::~nsXULPDGlobalObject()
{
}

NS_IMPL_CYCLE_COLLECTION_CLASS(nsXULPDGlobalObject)
NS_IMPL_CYCLE_COLLECTION_UNLINK_0(nsXULPDGlobalObject)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsXULPDGlobalObject)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mContext)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsXULPDGlobalObject)
  NS_INTERFACE_MAP_ENTRY(nsIScriptGlobalObject)
  NS_INTERFACE_MAP_ENTRY(nsIScriptObjectPrincipal)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIScriptGlobalObject)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(nsXULPDGlobalObject)
NS_IMPL_CYCLE_COLLECTING_RELEASE(nsXULPDGlobalObject)

//----------------------------------------------------------------------
//
// nsIScriptGlobalObject methods
//

nsresult
nsXULPDGlobalObject::SetScriptContext(PRUint32 lang_id, nsIScriptContext *aScriptContext)
{
  NS_ABORT_IF_FALSE(lang_id == nsIProgrammingLanguage::JAVASCRIPT,
                    "We don't support this language ID");
  // almost a clone of nsGlobalWindow
  if (!aScriptContext) {
    NS_WARNING("Possibly early removal of script object, see bug #41608");
  } else {
    // should probably assert the context is clean???
    aScriptContext->WillInitializeContext();
    nsresult rv = aScriptContext->InitContext();
    NS_ENSURE_SUCCESS(rv, rv);
  }

  NS_ASSERTION(!aScriptContext || !mContext, "Bad call to SetContext()!");

  JSObject* global = NULL;

  if (aScriptContext) {
    aScriptContext->SetGCOnDestruction(false);
    aScriptContext->DidInitializeContext();
    global = aScriptContext->GetNativeGlobal();
    NS_ASSERTION(global, "GetNativeGlobal returned NULL!");
  }
  mContext = aScriptContext;
  mJSObject = global;
  return NS_OK;
}

nsresult
nsXULPDGlobalObject::EnsureScriptEnvironment(PRUint32 lang_id)
{
  NS_ABORT_IF_FALSE(lang_id == nsIProgrammingLanguage::JAVASCRIPT,
                    "We don't support this language ID");
  if (mContext) {
    return NS_OK;
  }
  NS_ASSERTION(!mJSObject, "Have global without context?");

  nsCOMPtr<nsIScriptRuntime> languageRuntime;
  nsresult rv = NS_GetScriptRuntimeByID(nsIProgrammingLanguage::JAVASCRIPT,
                                        getter_AddRefs(languageRuntime));
  NS_ENSURE_SUCCESS(rv, NS_OK);

  nsCOMPtr<nsIScriptContext> ctxNew = languageRuntime->CreateContext();
  // We have to setup a special global object.  We do this then
  // attach it as the global for this context.  Then, ::SetScriptContext
  // will re-fetch the global and set it up in our language globals array.
  {
    JSContext *cx = ctxNew->GetNativeContext();
    JSAutoRequest ar(cx);

    nsIPrincipal *principal = GetPrincipal();
    JSObject *newGlob;
    JSCompartment *compartment;

    rv = xpc_CreateGlobalObject(cx, &gSharedGlobalClass, principal, nsnull,
                                false, &newGlob, &compartment);
    NS_ENSURE_SUCCESS(rv, NS_OK);

    ::JS_SetGlobalObject(cx, newGlob);

    // Add an owning reference from JS back to us. This'll be
    // released when the JSObject is finalized.
    ::JS_SetPrivate(newGlob, this);
    NS_ADDREF(this);
  }

  NS_ENSURE_SUCCESS(rv, NS_OK);
  rv = SetScriptContext(lang_id, ctxNew);
  NS_ENSURE_SUCCESS(rv, NS_OK);
  return NS_OK;
}

nsIScriptContext*
nsXULPDGlobalObject::GetScriptContext(PRUint32 lang_id)
{
  NS_ABORT_IF_FALSE(lang_id == nsIProgrammingLanguage::JAVASCRIPT,
                    "We don't support this language ID");
  // This global object creates a context on demand - do that now.
  nsresult rv = EnsureScriptEnvironment(nsIProgrammingLanguage::JAVASCRIPT);
  if (NS_FAILED(rv)) {
    NS_ERROR("Failed to setup script language");
    return NULL;
  }
  // Note that EnsureScriptEnvironment has validated lang_id
  return mContext;
}

JSObject*
nsXULPDGlobalObject::GetGlobalJSObject()
{
  return mJSObject;
}


void
nsXULPDGlobalObject::ClearGlobalObjectOwner()
{
  NS_ASSERTION(!mCachedPrincipal, "This shouldn't ever be set until now!");

  // Cache mGlobalObjectOwner's principal if possible.
  if (this != nsXULPrototypeDocument::gSystemGlobal)
    mCachedPrincipal = mGlobalObjectOwner->DocumentPrincipal();

  mContext = NULL;
  mGlobalObjectOwner = NULL;
}


void
nsXULPDGlobalObject::OnFinalize(JSObject* aObject)
{
  mJSObject = NULL;
}

void
nsXULPDGlobalObject::SetScriptsEnabled(bool aEnabled, bool aFireTimeouts)
{
  // We don't care...
}

//----------------------------------------------------------------------
//
// nsIScriptObjectPrincipal methods
//

nsIPrincipal*
nsXULPDGlobalObject::GetPrincipal()
{
    if (!mGlobalObjectOwner) {
        // See nsXULPrototypeDocument::NewXULPDGlobalObject, the comment
        // about gSystemGlobal implying gSystemPrincipal.
        if (this == nsXULPrototypeDocument::gSystemGlobal) {
            return nsXULPrototypeDocument::gSystemPrincipal;
        }
        // Return the cached principal if it exists.
        return mCachedPrincipal;
    }

    return mGlobalObjectOwner->DocumentPrincipal();
}
