nsScriptLoader.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* A class that handles loading and evaluation of <script> elements.
*/
#ifndef __nsScriptLoader_h__
#define __nsScriptLoader_h__
#include "nsCOMPtr.h"
#include "nsIScriptElement.h"
#include "nsCOMArray.h"
#include "nsTArray.h"
#include "nsAutoPtr.h"
#include "nsIDocument.h"
#include "nsIStreamLoader.h"
#include "mozilla/CORSMode.h"
#include "mozilla/LinkedList.h"
#include "mozilla/net/ReferrerPolicy.h"
class nsScriptLoadRequestList;
class nsIURI;
namespace JS {
class SourceBufferHolder;
}
namespace mozilla {
namespace dom {
class AutoJSAPI;
}
}
//////////////////////////////////////////////////////////////
// Per-request data structure
//////////////////////////////////////////////////////////////
class nsScriptLoadRequest final : public nsISupports,
private mozilla::LinkedListElement<nsScriptLoadRequest>
{
~nsScriptLoadRequest()
{
js_free(mScriptTextBuf);
}
typedef LinkedListElement<nsScriptLoadRequest> super;
// Allow LinkedListElement<nsScriptLoadRequest> to cast us to itself as needed.
friend class mozilla::LinkedListElement<nsScriptLoadRequest>;
friend class nsScriptLoadRequestList;
public:
nsScriptLoadRequest(nsIScriptElement* aElement,
uint32_t aVersion,
mozilla::CORSMode aCORSMode)
: mElement(aElement),
mLoading(true),
mIsInline(true),
mHasSourceMapURL(false),
mIsDefer(false),
mIsAsync(false),
mIsNonAsyncScriptInserted(false),
mIsXSLT(false),
mIsCanceled(false),
mScriptTextBuf(nullptr),
mScriptTextLength(0),
mJSVersion(aVersion),
mLineNo(1),
mCORSMode(aCORSMode),
mReferrerPolicy(mozilla::net::RP_Default)
{
}
NS_DECL_THREADSAFE_ISUPPORTS
void FireScriptAvailable(nsresult aResult)
{
mElement->ScriptAvailable(aResult, mElement, mIsInline, mURI, mLineNo);
}
void FireScriptEvaluated(nsresult aResult)
{
mElement->ScriptEvaluated(aResult, mElement, mIsInline);
}
bool IsPreload()
{
return mElement == nullptr;
}
void Cancel()
{
mIsCanceled = true;
}
bool IsCanceled() const
{
return mIsCanceled;
}
using super::getNext;
using super::isInList;
nsCOMPtr<nsIScriptElement> mElement;
bool mLoading; // Are we still waiting for a load to complete?
bool mIsInline; // Is the script inline or loaded?
bool mHasSourceMapURL; // Does the HTTP header have a source map url?
bool mIsDefer; // True if we live in mDeferRequests.
bool mIsAsync; // True if we live in mLoadingAsyncRequests or mLoadedAsyncRequests.
bool mIsNonAsyncScriptInserted; // True if we live in mNonAsyncExternalScriptInsertedRequests
bool mIsXSLT; // True if we live in mXSLTRequests.
bool mIsCanceled; // True if we have been explicitly canceled.
nsString mSourceMapURL; // Holds source map url for loaded scripts
char16_t* mScriptTextBuf; // Holds script text for non-inline scripts. Don't
size_t mScriptTextLength; // use nsString so we can give ownership to jsapi.
uint32_t mJSVersion;
nsCOMPtr<nsIURI> mURI;
nsCOMPtr<nsIPrincipal> mOriginPrincipal;
nsAutoCString mURL; // Keep the URI's filename alive during off thread parsing.
int32_t mLineNo;
const mozilla::CORSMode mCORSMode;
mozilla::net::ReferrerPolicy mReferrerPolicy;
};
class nsScriptLoadRequestList : private mozilla::LinkedList<nsScriptLoadRequest>
{
typedef mozilla::LinkedList<nsScriptLoadRequest> super;
public:
~nsScriptLoadRequestList();
void Clear();
#ifdef DEBUG
bool Contains(nsScriptLoadRequest* aElem);
#endif // DEBUG
using super::getFirst;
using super::isEmpty;
void AppendElement(nsScriptLoadRequest* aElem)
{
MOZ_ASSERT(!aElem->isInList());
NS_ADDREF(aElem);
insertBack(aElem);
}
MOZ_WARN_UNUSED_RESULT
already_AddRefed<nsScriptLoadRequest> Steal(nsScriptLoadRequest* aElem)
{
aElem->removeFrom(*this);
return dont_AddRef(aElem);
}
MOZ_WARN_UNUSED_RESULT
already_AddRefed<nsScriptLoadRequest> StealFirst()
{
MOZ_ASSERT(!isEmpty());
return Steal(getFirst());
}
};
//////////////////////////////////////////////////////////////
// Script loader implementation
//////////////////////////////////////////////////////////////
class nsScriptLoader final : public nsIStreamLoaderObserver
{
class MOZ_STACK_CLASS AutoCurrentScriptUpdater
{
public:
AutoCurrentScriptUpdater(nsScriptLoader* aScriptLoader,
nsIScriptElement* aCurrentScript)
: mOldScript(aScriptLoader->mCurrentScript)
, mScriptLoader(aScriptLoader)
{
mScriptLoader->mCurrentScript = aCurrentScript;
}
~AutoCurrentScriptUpdater()
{
mScriptLoader->mCurrentScript.swap(mOldScript);
}
private:
nsCOMPtr<nsIScriptElement> mOldScript;
nsScriptLoader* mScriptLoader;
};
friend class nsScriptRequestProcessor;
friend class AutoCurrentScriptUpdater;
public:
explicit nsScriptLoader(nsIDocument* aDocument);
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 = nullptr;
}
/**
* 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 true 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.
*/
bool 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;
}
nsIScriptElement* GetCurrentParserInsertedScript()
{
return mCurrentParserInsertedScript;
}
/**
* Whether the loader is enabled or not.
* When disabled, processing of new script elements is disabled.
* Any call to ProcessScriptElement() will return false. Note that
* this DOES NOT disable currently loading or executing scripts.
*/
bool GetEnabled()
{
return mEnabled;
}
void SetEnabled(bool 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 aBufOut [out] char16_t array allocated by ConvertToUTF16 and
* containing data converted to unicode. Caller must
* js_free() this data when no longer needed.
* @param aLengthOut [out] Length of array returned in aBufOut in number
* of char16_t code units.
*/
static nsresult ConvertToUTF16(nsIChannel* aChannel, const uint8_t* aData,
uint32_t aLength,
const nsAString& aHintCharset,
nsIDocument* aDocument,
char16_t*& aBufOut, size_t& aLengthOut);
/**
* 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);
/**
* Starts deferring deferred scripts and puts them in the mDeferredRequests
* queue instead.
*/
void BeginDeferringScripts()
{
mDeferEnabled = 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(bool aTerminated);
/**
* Returns the number of pending scripts, deferred or not.
*/
uint32_t HasPendingOrCurrentScripts()
{
return mCurrentScript || mParserBlockingRequest;
}
/**
* 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.
* @param aCrossOrigin The crossorigin attribute for the script.
* Void if not present.
* @param aScriptFromHead Whether or not the script was a child of head
*/
virtual void PreloadURI(nsIURI *aURI, const nsAString &aCharset,
const nsAString &aType,
const nsAString &aCrossOrigin,
bool aScriptFromHead,
const mozilla::net::ReferrerPolicy aReferrerPolicy);
/**
* Process a request that was deferred so that the script could be compiled
* off thread.
*/
nsresult ProcessOffThreadRequest(nsScriptLoadRequest *aRequest,
void **aOffThreadToken);
bool AddPendingChildLoader(nsScriptLoader* aChild) {
return mPendingChildLoaders.AppendElement(aChild) != nullptr;
}
private:
virtual ~nsScriptLoader();
/**
* Unblocks the creator parser of the parser-blocking scripts.
*/
void UnblockParser(nsScriptLoadRequest* aParserBlockingRequest);
/**
* Asynchronously resumes the creator parser of the parser-blocking scripts.
*/
void ContinueParserAsync(nsScriptLoadRequest* aParserBlockingRequest);
/**
* 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,
bool aScriptFromHead);
/**
* 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.
*/
bool ReadyToExecuteScripts();
/**
* Return whether just this loader is ready to execute scripts.
*/
bool SelfReadyToExecuteScripts()
{
return mEnabled && !mBlockerCount;
}
nsresult AttemptAsyncScriptParse(nsScriptLoadRequest* aRequest);
nsresult ProcessRequest(nsScriptLoadRequest* aRequest,
void **aOffThreadToken = nullptr);
void FireScriptAvailable(nsresult aResult,
nsScriptLoadRequest* aRequest);
void FireScriptEvaluated(nsresult aResult,
nsScriptLoadRequest* aRequest);
nsresult EvaluateScript(nsScriptLoadRequest* aRequest,
JS::SourceBufferHolder& aSrcBuf,
void **aOffThreadToken);
already_AddRefed<nsIScriptGlobalObject> GetScriptGlobalObject();
void FillCompileOptionsForRequest(const mozilla::dom::AutoJSAPI &jsapi,
nsScriptLoadRequest *aRequest,
JS::Handle<JSObject *> aScopeChain,
JS::CompileOptions *aOptions);
nsresult PrepareLoadedRequest(nsScriptLoadRequest* aRequest,
nsIStreamLoader* aLoader,
nsresult aStatus,
uint32_t aStringLen,
const uint8_t* aString);
void AddDeferRequest(nsScriptLoadRequest* aRequest);
bool MaybeRemovedDeferRequests();
nsIDocument* mDocument; // [WEAK]
nsCOMArray<nsIScriptLoaderObserver> mObservers;
nsScriptLoadRequestList mNonAsyncExternalScriptInsertedRequests;
// mLoadingAsyncRequests holds async requests while they're loading; when they
// have been loaded they are moved to mLoadedAsyncRequests.
nsScriptLoadRequestList mLoadingAsyncRequests;
nsScriptLoadRequestList mLoadedAsyncRequests;
nsScriptLoadRequestList mDeferRequests;
nsScriptLoadRequestList mXSLTRequests;
nsRefPtr<nsScriptLoadRequest> mParserBlockingRequest;
// In mRequests, the additional information here is stored by the element.
struct PreloadInfo {
nsRefPtr<nsScriptLoadRequest> mRequest;
nsString mCharset;
};
struct PreloadRequestComparator {
bool Equals(const PreloadInfo &aPi, nsScriptLoadRequest * const &aRequest)
const
{
return aRequest == aPi.mRequest;
}
};
struct PreloadURIComparator {
bool Equals(const PreloadInfo &aPi, nsIURI * const &aURI) const;
};
nsTArray<PreloadInfo> mPreloads;
nsCOMPtr<nsIScriptElement> mCurrentScript;
nsCOMPtr<nsIScriptElement> mCurrentParserInsertedScript;
// XXXbz do we want to cycle-collect these or something? Not sure.
nsTArray< nsRefPtr<nsScriptLoader> > mPendingChildLoaders;
uint32_t mBlockerCount;
bool mEnabled;
bool mDeferEnabled;
bool mDocumentParsingDone;
bool mBlockingDOMContentLoaded;
};
class nsAutoScriptLoaderDisabler
{
public:
explicit nsAutoScriptLoaderDisabler(nsIDocument* aDoc)
{
mLoader = aDoc->ScriptLoader();
mWasEnabled = mLoader->GetEnabled();
if (mWasEnabled) {
mLoader->SetEnabled(false);
}
}
~nsAutoScriptLoaderDisabler()
{
if (mWasEnabled) {
mLoader->SetEnabled(true);
}
}
bool mWasEnabled;
nsRefPtr<nsScriptLoader> mLoader;
};
#endif //__nsScriptLoader_h__
