gecko/content/base/src/nsScriptLoader.h
2009-11-09 17:04:24 -08:00

333 lines
11 KiB
C++

/* -*- 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.
*
* The Initial Developer of the Original Code is
* Netscape Communications.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Vidur Apparao <vidur@netscape.com> (original author)
*
* 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 ***** */
/*
* A class that handles loading and evaluation of <script> elements.
*/
#ifndef __nsScriptLoader_h__
#define __nsScriptLoader_h__
#include "nsCOMPtr.h"
#include "nsIScriptElement.h"
#include "nsIURI.h"
#include "nsCOMArray.h"
#include "nsTArray.h"
#include "nsAutoPtr.h"
#include "nsIDocument.h"
#include "nsIStreamLoader.h"
class nsScriptLoadRequest;
//////////////////////////////////////////////////////////////
// Script loader implementation
//////////////////////////////////////////////////////////////
class nsScriptLoader : public nsIStreamLoaderObserver
{
public:
nsScriptLoader(nsIDocument* aDocument);
virtual ~nsScriptLoader();
NS_DECL_ISUPPORTS
NS_DECL_NSISTREAMLOADEROBSERVER
/**
* The loader maintains a weak reference to the document with
* which it is initialized. This call forces the reference to
* be dropped.
*/
void DropDocumentReference()
{
mDocument = nsnull;
}
/**
* Add an observer for all scripts loaded through this loader.
*
* @param aObserver observer for all script processing.
*/
nsresult AddObserver(nsIScriptLoaderObserver* aObserver)
{
return mObservers.AppendObject(aObserver) ? NS_OK :
NS_ERROR_OUT_OF_MEMORY;
}
/**
* Remove an observer.
*
* @param aObserver observer to be removed
*/
void RemoveObserver(nsIScriptLoaderObserver* aObserver)
{
mObservers.RemoveObject(aObserver);
}
/**
* Process a script element. This will include both loading the
* source of the element if it is not inline and evaluating
* the script itself.
*
* If the script is an inline script that can be executed immediately
* (i.e. there are no other scripts pending) then ScriptAvailable
* and ScriptEvaluated will be called before the function returns.
*
* If NS_ERROR_HTMLPARSER_BLOCK is returned the script could not be
* executed immediately. In this case ScriptAvailable is guaranteed
* to be called at a later point (as well as possibly ScriptEvaluated).
*
* @param aElement The element representing the script to be loaded and
* evaluated.
*/
nsresult ProcessScriptElement(nsIScriptElement* aElement);
/**
* Gets the currently executing script. This is useful if you want to
* generate a unique key based on the currently executing script.
*/
nsIScriptElement* GetCurrentScript()
{
return mCurrentScript;
}
/**
* Whether the loader is enabled or not.
* When disabled, processing of new script elements is disabled.
* Any call to ProcessScriptElement() will fail with a return code of
* NS_ERROR_NOT_AVAILABLE. Note that this DOES NOT disable
* currently loading or executing scripts.
*/
PRBool GetEnabled()
{
return mEnabled;
}
void SetEnabled(PRBool aEnabled)
{
if (!mEnabled && aEnabled) {
ProcessPendingRequestsAsync();
}
mEnabled = aEnabled;
}
/**
* Add/remove blocker. Blockers will stop scripts from executing, but not
* from loading.
*/
void AddExecuteBlocker()
{
++mBlockerCount;
}
void RemoveExecuteBlocker()
{
if (!--mBlockerCount) {
ProcessPendingRequestsAsync();
}
}
/**
* Convert the given buffer to a UTF-16 string.
* @param aChannel Channel corresponding to the data. May be null.
* @param aData The data to convert
* @param aLength Length of the data
* @param aHintCharset Hint for the character set (e.g., from a charset
* attribute). May be the empty string.
* @param aDocument Document which the data is loaded for. Must not be
* null.
* @param aString [out] Data as converted to unicode
*/
static nsresult ConvertToUTF16(nsIChannel* aChannel, const PRUint8* aData,
PRUint32 aLength,
const nsString& aHintCharset,
nsIDocument* aDocument, nsString& aString);
/**
* Processes any pending requests that are ready for processing.
*/
void ProcessPendingRequests();
/**
* Check whether it's OK to load a script from aURI in
* aDocument.
*/
static nsresult ShouldLoadScript(nsIDocument* aDocument,
nsISupports* aContext,
nsIURI* aURI,
const nsAString &aType);
/**
* Check whether it's OK to execute a script loaded via aChannel in
* aDocument.
*/
static PRBool ShouldExecuteScript(nsIDocument* aDocument,
nsIChannel* aChannel);
/**
* Starts deferring deferred scripts and puts them in the mDeferredRequests
* queue instead.
*/
void BeginDeferringScripts()
{
mDeferEnabled = PR_TRUE;
if (mDocument) {
mDocument->BlockOnload();
}
}
/**
* Notifies the script loader that parsing is done. If aTerminated is true,
* this will drop any pending scripts that haven't run yet. Otherwise, it
* will stops deferring scripts and immediately processes the
* mDeferredRequests queue.
*
* WARNING: This function will synchronously execute content scripts, so be
* prepared that the world might change around you.
*/
void ParsingComplete(PRBool aTerminated);
/**
* Returns the number of pending scripts, deferred or not.
*/
PRUint32 HasPendingOrCurrentScripts()
{
return mCurrentScript || GetFirstPendingRequest();
}
/**
* Adds aURI to the preload list and starts loading it.
*
* @param aURI The URI of the external script.
* @param aCharset The charset parameter for the script.
* @param aType The type parameter for the script.
*/
virtual void PreloadURI(nsIURI *aURI, const nsAString &aCharset,
const nsAString &aType);
protected:
/**
* Helper function to check the content policy for a given request.
*/
static nsresult CheckContentPolicy(nsIDocument* aDocument,
nsISupports *aContext,
nsIURI *aURI,
const nsAString &aType);
/**
* Start a load for aRequest's URI.
*/
nsresult StartLoad(nsScriptLoadRequest *aRequest, const nsAString &aType);
/**
* Process any pending requests asynchronously (i.e. off an event) if there
* are any. Note that this is a no-op if there aren't any currently pending
* requests.
*
* This function is virtual to allow cross-library calls to SetEnabled()
*/
virtual void ProcessPendingRequestsAsync();
/**
* If true, the loader is ready to execute scripts, and so are all its
* ancestors. If the loader itself is ready but some ancestor is not, this
* function will add an execute blocker and ask the ancestor to remove it
* once it becomes ready.
*/
PRBool ReadyToExecuteScripts();
/**
* Return whether just this loader is ready to execute scripts.
*/
PRBool SelfReadyToExecuteScripts()
{
return mEnabled && !mBlockerCount;
}
PRBool AddPendingChildLoader(nsScriptLoader* aChild) {
return mPendingChildLoaders.AppendElement(aChild) != nsnull;
}
nsresult ProcessRequest(nsScriptLoadRequest* aRequest);
void FireScriptAvailable(nsresult aResult,
nsScriptLoadRequest* aRequest);
void FireScriptEvaluated(nsresult aResult,
nsScriptLoadRequest* aRequest);
nsresult EvaluateScript(nsScriptLoadRequest* aRequest,
const nsAFlatString& aScript);
nsresult PrepareLoadedRequest(nsScriptLoadRequest* aRequest,
nsIStreamLoader* aLoader,
nsresult aStatus,
PRUint32 aStringLen,
const PRUint8* aString);
// Returns the first pending (non deferred) request
nsScriptLoadRequest* GetFirstPendingRequest();
nsIDocument* mDocument; // [WEAK]
nsCOMArray<nsIScriptLoaderObserver> mObservers;
nsCOMArray<nsScriptLoadRequest> mRequests;
nsCOMArray<nsScriptLoadRequest> mAsyncRequests;
// In mRequests, the additional information here is stored by the element.
struct PreloadInfo {
nsRefPtr<nsScriptLoadRequest> mRequest;
nsString mCharset;
};
struct PreloadRequestComparator {
PRBool Equals(const PreloadInfo &aPi, nsScriptLoadRequest * const &aRequest)
const
{
return aRequest == aPi.mRequest;
}
};
struct PreloadURIComparator {
PRBool Equals(const PreloadInfo &aPi, nsIURI * const &aURI) const;
};
nsTArray<PreloadInfo> mPreloads;
nsCOMPtr<nsIScriptElement> mCurrentScript;
// XXXbz do we want to cycle-collect these or something? Not sure.
nsTArray< nsRefPtr<nsScriptLoader> > mPendingChildLoaders;
PRUint32 mBlockerCount;
PRPackedBool mEnabled;
PRPackedBool mDeferEnabled;
PRPackedBool mUnblockOnloadWhenDoneProcessing;
};
#endif //__nsScriptLoader_h__