1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/base/src/nsScriptLoader.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,366 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +/*
1.10 + * A class that handles loading and evaluation of <script> elements.
1.11 + */
1.12 +
1.13 +#ifndef __nsScriptLoader_h__
1.14 +#define __nsScriptLoader_h__
1.15 +
1.16 +#include "nsCOMPtr.h"
1.17 +#include "nsIScriptElement.h"
1.18 +#include "nsCOMArray.h"
1.19 +#include "nsTArray.h"
1.20 +#include "nsAutoPtr.h"
1.21 +#include "nsIDocument.h"
1.22 +#include "nsIStreamLoader.h"
1.23 +
1.24 +class nsScriptLoadRequest;
1.25 +class nsIURI;
1.26 +
1.27 +namespace JS {
1.28 + class SourceBufferHolder;
1.29 +}
1.30 +
1.31 +//////////////////////////////////////////////////////////////
1.32 +// Script loader implementation
1.33 +//////////////////////////////////////////////////////////////
1.34 +
1.35 +class nsScriptLoader : public nsIStreamLoaderObserver
1.36 +{
1.37 + friend class nsScriptRequestProcessor;
1.38 +public:
1.39 + nsScriptLoader(nsIDocument* aDocument);
1.40 + virtual ~nsScriptLoader();
1.41 +
1.42 + NS_DECL_ISUPPORTS
1.43 + NS_DECL_NSISTREAMLOADEROBSERVER
1.44 +
1.45 + /**
1.46 + * The loader maintains a weak reference to the document with
1.47 + * which it is initialized. This call forces the reference to
1.48 + * be dropped.
1.49 + */
1.50 + void DropDocumentReference()
1.51 + {
1.52 + mDocument = nullptr;
1.53 + }
1.54 +
1.55 + /**
1.56 + * Add an observer for all scripts loaded through this loader.
1.57 + *
1.58 + * @param aObserver observer for all script processing.
1.59 + */
1.60 + nsresult AddObserver(nsIScriptLoaderObserver* aObserver)
1.61 + {
1.62 + return mObservers.AppendObject(aObserver) ? NS_OK :
1.63 + NS_ERROR_OUT_OF_MEMORY;
1.64 + }
1.65 +
1.66 + /**
1.67 + * Remove an observer.
1.68 + *
1.69 + * @param aObserver observer to be removed
1.70 + */
1.71 + void RemoveObserver(nsIScriptLoaderObserver* aObserver)
1.72 + {
1.73 + mObservers.RemoveObject(aObserver);
1.74 + }
1.75 +
1.76 + /**
1.77 + * Process a script element. This will include both loading the
1.78 + * source of the element if it is not inline and evaluating
1.79 + * the script itself.
1.80 + *
1.81 + * If the script is an inline script that can be executed immediately
1.82 + * (i.e. there are no other scripts pending) then ScriptAvailable
1.83 + * and ScriptEvaluated will be called before the function returns.
1.84 + *
1.85 + * If true is returned the script could not be executed immediately.
1.86 + * In this case ScriptAvailable is guaranteed to be called at a later
1.87 + * point (as well as possibly ScriptEvaluated).
1.88 + *
1.89 + * @param aElement The element representing the script to be loaded and
1.90 + * evaluated.
1.91 + */
1.92 + bool ProcessScriptElement(nsIScriptElement* aElement);
1.93 +
1.94 + /**
1.95 + * Gets the currently executing script. This is useful if you want to
1.96 + * generate a unique key based on the currently executing script.
1.97 + */
1.98 + nsIScriptElement* GetCurrentScript()
1.99 + {
1.100 + return mCurrentScript;
1.101 + }
1.102 +
1.103 + nsIScriptElement* GetCurrentParserInsertedScript()
1.104 + {
1.105 + return mCurrentParserInsertedScript;
1.106 + }
1.107 +
1.108 + /**
1.109 + * Whether the loader is enabled or not.
1.110 + * When disabled, processing of new script elements is disabled.
1.111 + * Any call to ProcessScriptElement() will return false. Note that
1.112 + * this DOES NOT disable currently loading or executing scripts.
1.113 + */
1.114 + bool GetEnabled()
1.115 + {
1.116 + return mEnabled;
1.117 + }
1.118 + void SetEnabled(bool aEnabled)
1.119 + {
1.120 + if (!mEnabled && aEnabled) {
1.121 + ProcessPendingRequestsAsync();
1.122 + }
1.123 + mEnabled = aEnabled;
1.124 + }
1.125 +
1.126 + /**
1.127 + * Add/remove blocker. Blockers will stop scripts from executing, but not
1.128 + * from loading.
1.129 + */
1.130 + void AddExecuteBlocker()
1.131 + {
1.132 + ++mBlockerCount;
1.133 + }
1.134 + void RemoveExecuteBlocker()
1.135 + {
1.136 + if (!--mBlockerCount) {
1.137 + ProcessPendingRequestsAsync();
1.138 + }
1.139 + }
1.140 +
1.141 + /**
1.142 + * Convert the given buffer to a UTF-16 string.
1.143 + * @param aChannel Channel corresponding to the data. May be null.
1.144 + * @param aData The data to convert
1.145 + * @param aLength Length of the data
1.146 + * @param aHintCharset Hint for the character set (e.g., from a charset
1.147 + * attribute). May be the empty string.
1.148 + * @param aDocument Document which the data is loaded for. Must not be
1.149 + * null.
1.150 + * @param aBufOut [out] jschar array allocated by ConvertToUTF16 and
1.151 + * containing data converted to unicode. Caller must
1.152 + * js_free() this data when no longer needed.
1.153 + * @param aLengthOut [out] Length of array returned in aBufOut in number
1.154 + * of jschars.
1.155 + */
1.156 + static nsresult ConvertToUTF16(nsIChannel* aChannel, const uint8_t* aData,
1.157 + uint32_t aLength,
1.158 + const nsAString& aHintCharset,
1.159 + nsIDocument* aDocument,
1.160 + jschar*& aBufOut, size_t& aLengthOut);
1.161 +
1.162 + /**
1.163 + * Processes any pending requests that are ready for processing.
1.164 + */
1.165 + void ProcessPendingRequests();
1.166 +
1.167 + /**
1.168 + * Check whether it's OK to load a script from aURI in
1.169 + * aDocument.
1.170 + */
1.171 + static nsresult ShouldLoadScript(nsIDocument* aDocument,
1.172 + nsISupports* aContext,
1.173 + nsIURI* aURI,
1.174 + const nsAString &aType);
1.175 +
1.176 + /**
1.177 + * Starts deferring deferred scripts and puts them in the mDeferredRequests
1.178 + * queue instead.
1.179 + */
1.180 + void BeginDeferringScripts()
1.181 + {
1.182 + mDeferEnabled = true;
1.183 + if (mDocument) {
1.184 + mDocument->BlockOnload();
1.185 + }
1.186 + }
1.187 +
1.188 + /**
1.189 + * Notifies the script loader that parsing is done. If aTerminated is true,
1.190 + * this will drop any pending scripts that haven't run yet. Otherwise, it
1.191 + * will stops deferring scripts and immediately processes the
1.192 + * mDeferredRequests queue.
1.193 + *
1.194 + * WARNING: This function will synchronously execute content scripts, so be
1.195 + * prepared that the world might change around you.
1.196 + */
1.197 + void ParsingComplete(bool aTerminated);
1.198 +
1.199 + /**
1.200 + * Returns the number of pending scripts, deferred or not.
1.201 + */
1.202 + uint32_t HasPendingOrCurrentScripts()
1.203 + {
1.204 + return mCurrentScript || mParserBlockingRequest;
1.205 + }
1.206 +
1.207 + /**
1.208 + * Adds aURI to the preload list and starts loading it.
1.209 + *
1.210 + * @param aURI The URI of the external script.
1.211 + * @param aCharset The charset parameter for the script.
1.212 + * @param aType The type parameter for the script.
1.213 + * @param aCrossOrigin The crossorigin attribute for the script.
1.214 + * Void if not present.
1.215 + * @param aScriptFromHead Whether or not the script was a child of head
1.216 + */
1.217 + virtual void PreloadURI(nsIURI *aURI, const nsAString &aCharset,
1.218 + const nsAString &aType,
1.219 + const nsAString &aCrossOrigin,
1.220 + bool aScriptFromHead);
1.221 +
1.222 + /**
1.223 + * Process a request that was deferred so that the script could be compiled
1.224 + * off thread.
1.225 + */
1.226 + nsresult ProcessOffThreadRequest(nsScriptLoadRequest *aRequest,
1.227 + void **aOffThreadToken);
1.228 +
1.229 +private:
1.230 + /**
1.231 + * Unblocks the creator parser of the parser-blocking scripts.
1.232 + */
1.233 + void UnblockParser(nsScriptLoadRequest* aParserBlockingRequest);
1.234 +
1.235 + /**
1.236 + * Asynchronously resumes the creator parser of the parser-blocking scripts.
1.237 + */
1.238 + void ContinueParserAsync(nsScriptLoadRequest* aParserBlockingRequest);
1.239 +
1.240 +
1.241 + /**
1.242 + * Helper function to check the content policy for a given request.
1.243 + */
1.244 + static nsresult CheckContentPolicy(nsIDocument* aDocument,
1.245 + nsISupports *aContext,
1.246 + nsIURI *aURI,
1.247 + const nsAString &aType);
1.248 +
1.249 + /**
1.250 + * Start a load for aRequest's URI.
1.251 + */
1.252 + nsresult StartLoad(nsScriptLoadRequest *aRequest, const nsAString &aType,
1.253 + bool aScriptFromHead);
1.254 +
1.255 + /**
1.256 + * Process any pending requests asynchronously (i.e. off an event) if there
1.257 + * are any. Note that this is a no-op if there aren't any currently pending
1.258 + * requests.
1.259 + *
1.260 + * This function is virtual to allow cross-library calls to SetEnabled()
1.261 + */
1.262 + virtual void ProcessPendingRequestsAsync();
1.263 +
1.264 + /**
1.265 + * If true, the loader is ready to execute scripts, and so are all its
1.266 + * ancestors. If the loader itself is ready but some ancestor is not, this
1.267 + * function will add an execute blocker and ask the ancestor to remove it
1.268 + * once it becomes ready.
1.269 + */
1.270 + bool ReadyToExecuteScripts();
1.271 +
1.272 + /**
1.273 + * Return whether just this loader is ready to execute scripts.
1.274 + */
1.275 + bool SelfReadyToExecuteScripts()
1.276 + {
1.277 + return mEnabled && !mBlockerCount;
1.278 + }
1.279 +
1.280 + bool AddPendingChildLoader(nsScriptLoader* aChild) {
1.281 + return mPendingChildLoaders.AppendElement(aChild) != nullptr;
1.282 + }
1.283 +
1.284 + nsresult AttemptAsyncScriptParse(nsScriptLoadRequest* aRequest);
1.285 + nsresult ProcessRequest(nsScriptLoadRequest* aRequest,
1.286 + void **aOffThreadToken = nullptr);
1.287 + void FireScriptAvailable(nsresult aResult,
1.288 + nsScriptLoadRequest* aRequest);
1.289 + void FireScriptEvaluated(nsresult aResult,
1.290 + nsScriptLoadRequest* aRequest);
1.291 + nsresult EvaluateScript(nsScriptLoadRequest* aRequest,
1.292 + JS::SourceBufferHolder& aSrcBuf,
1.293 + void **aOffThreadToken);
1.294 +
1.295 + already_AddRefed<nsIScriptGlobalObject> GetScriptGlobalObject();
1.296 + void FillCompileOptionsForRequest(nsScriptLoadRequest *aRequest,
1.297 + JS::Handle<JSObject *> aScopeChain,
1.298 + JS::CompileOptions *aOptions);
1.299 +
1.300 + nsresult PrepareLoadedRequest(nsScriptLoadRequest* aRequest,
1.301 + nsIStreamLoader* aLoader,
1.302 + nsresult aStatus,
1.303 + uint32_t aStringLen,
1.304 + const uint8_t* aString);
1.305 +
1.306 + void AddDeferRequest(nsScriptLoadRequest* aRequest);
1.307 + bool MaybeRemovedDeferRequests();
1.308 +
1.309 + nsIDocument* mDocument; // [WEAK]
1.310 + nsCOMArray<nsIScriptLoaderObserver> mObservers;
1.311 + nsTArray<nsRefPtr<nsScriptLoadRequest> > mNonAsyncExternalScriptInsertedRequests;
1.312 + nsTArray<nsRefPtr<nsScriptLoadRequest> > mAsyncRequests;
1.313 + nsTArray<nsRefPtr<nsScriptLoadRequest> > mDeferRequests;
1.314 + nsTArray<nsRefPtr<nsScriptLoadRequest> > mXSLTRequests;
1.315 + nsRefPtr<nsScriptLoadRequest> mParserBlockingRequest;
1.316 +
1.317 + // In mRequests, the additional information here is stored by the element.
1.318 + struct PreloadInfo {
1.319 + nsRefPtr<nsScriptLoadRequest> mRequest;
1.320 + nsString mCharset;
1.321 + };
1.322 +
1.323 + struct PreloadRequestComparator {
1.324 + bool Equals(const PreloadInfo &aPi, nsScriptLoadRequest * const &aRequest)
1.325 + const
1.326 + {
1.327 + return aRequest == aPi.mRequest;
1.328 + }
1.329 + };
1.330 + struct PreloadURIComparator {
1.331 + bool Equals(const PreloadInfo &aPi, nsIURI * const &aURI) const;
1.332 + };
1.333 + nsTArray<PreloadInfo> mPreloads;
1.334 +
1.335 + nsCOMPtr<nsIScriptElement> mCurrentScript;
1.336 + nsCOMPtr<nsIScriptElement> mCurrentParserInsertedScript;
1.337 + // XXXbz do we want to cycle-collect these or something? Not sure.
1.338 + nsTArray< nsRefPtr<nsScriptLoader> > mPendingChildLoaders;
1.339 + uint32_t mBlockerCount;
1.340 + bool mEnabled;
1.341 + bool mDeferEnabled;
1.342 + bool mDocumentParsingDone;
1.343 + bool mBlockingDOMContentLoaded;
1.344 +};
1.345 +
1.346 +class nsAutoScriptLoaderDisabler
1.347 +{
1.348 +public:
1.349 + nsAutoScriptLoaderDisabler(nsIDocument* aDoc)
1.350 + {
1.351 + mLoader = aDoc->ScriptLoader();
1.352 + mWasEnabled = mLoader->GetEnabled();
1.353 + if (mWasEnabled) {
1.354 + mLoader->SetEnabled(false);
1.355 + }
1.356 + }
1.357 +
1.358 + ~nsAutoScriptLoaderDisabler()
1.359 + {
1.360 + if (mWasEnabled) {
1.361 + mLoader->SetEnabled(true);
1.362 + }
1.363 + }
1.364 +
1.365 + bool mWasEnabled;
1.366 + nsRefPtr<nsScriptLoader> mLoader;
1.367 +};
1.368 +
1.369 +#endif //__nsScriptLoader_h__
