pjs/uriloader/prefetch/nsPrefetchService.cpp

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/* ***** 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 Corporation.
* Portions created by the Initial Developer are Copyright (C) 2002
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Darin Fisher <darin@netscape.com> (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either 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 "nsPrefetchService.h"
#include "nsIServiceManager.h"
#include "nsICategoryManager.h"
#include "nsIObserverService.h"
#include "nsIPrefService.h"
#include "nsIPrefBranch.h"
#include "nsIDocCharset.h"
#include "nsIWebProgress.h"
#include "nsCURILoader.h"
#include "nsICachingChannel.h"
#include "nsICacheVisitor.h"
#include "nsIHttpChannel.h"
#include "nsIURL.h"
#include "nsNetUtil.h"
#include "nsString.h"
#include "nsXPIDLString.h"
#include "nsReadableUtils.h"
#include "prtime.h"
#include "prlog.h"
#include "plstr.h"
#if defined(PR_LOGGING)
//
// To enable logging (see prlog.h for full details):
//
// set NSPR_LOG_MODULES=nsPrefetch:5
// set NSPR_LOG_FILE=prefetch.log
//
// this enables PR_LOG_ALWAYS level information and places all output in
// the file http.log
//
static PRLogModuleInfo *gPrefetchLog;
#endif
#define LOG(args) PR_LOG(gPrefetchLog, 4, args)
#define LOG_ENABLED() PR_LOG_TEST(gPrefetchLog, 4)
static NS_DEFINE_IID(kDocLoaderServiceCID, NS_DOCUMENTLOADER_SERVICE_CID);
static NS_DEFINE_IID(kPrefServiceCID, NS_PREFSERVICE_CID);
//-----------------------------------------------------------------------------
// helpers
//-----------------------------------------------------------------------------
static inline PRUint32
PRTimeToSeconds(PRTime t_usec)
{
PRTime usec_per_sec;
PRUint32 t_sec;
LL_I2L(usec_per_sec, PR_USEC_PER_SEC);
LL_DIV(t_usec, t_usec, usec_per_sec);
LL_L2I(t_sec, t_usec);
return t_sec;
}
#define NowInSeconds() PRTimeToSeconds(PR_Now())
//-----------------------------------------------------------------------------
// nsPrefetchListener <public>
//-----------------------------------------------------------------------------
nsPrefetchListener::nsPrefetchListener(nsPrefetchService *aService)
{
NS_INIT_ISUPPORTS();
NS_ADDREF(mService = aService);
}
nsPrefetchListener::~nsPrefetchListener()
{
NS_RELEASE(mService);
}
//-----------------------------------------------------------------------------
// nsPrefetchListener <private>
//-----------------------------------------------------------------------------
NS_METHOD
nsPrefetchListener::ConsumeSegments(nsIInputStream *aInputStream,
void *aClosure,
const char *aFromSegment,
PRUint32 aOffset,
PRUint32 aCount,
PRUint32 *aBytesConsumed)
{
*aBytesConsumed = aCount;
return NS_OK;
}
//-----------------------------------------------------------------------------
// nsPrefetchListener::nsISupports
//-----------------------------------------------------------------------------
NS_IMPL_ISUPPORTS2(nsPrefetchListener,
nsIRequestObserver,
nsIStreamListener)
//-----------------------------------------------------------------------------
// nsPrefetchListener::nsIStreamListener
//-----------------------------------------------------------------------------
NS_IMETHODIMP
nsPrefetchListener::OnStartRequest(nsIRequest *aRequest,
nsISupports *aContext)
{
nsCOMPtr<nsICachingChannel> cachingChannel(do_QueryInterface(aRequest));
if (cachingChannel) {
// no need to prefetch a document that is already in the cache
PRBool fromCache;
if (NS_SUCCEEDED(cachingChannel->IsFromCache(&fromCache)) && fromCache) {
LOG(("document is already in the cache; canceling prefetch\n"));
return NS_BINDING_ABORTED;
}
// no need to prefetch a document that must be requested fresh each
// and every time.
nsCOMPtr<nsISupports> cacheToken;
cachingChannel->GetCacheToken(getter_AddRefs(cacheToken));
if (cacheToken) {
nsCOMPtr<nsICacheEntryInfo> entryInfo(do_QueryInterface(cacheToken));
if (entryInfo) {
PRUint32 expTime;
if (NS_SUCCEEDED(entryInfo->GetExpirationTime(&expTime))) {
if (NowInSeconds() >= expTime) {
LOG(("document cannot be reused from cache; canceling prefetch\n"));
return NS_BINDING_ABORTED;
}
}
}
}
}
return NS_OK;
}
NS_IMETHODIMP
nsPrefetchListener::OnDataAvailable(nsIRequest *aRequest,
nsISupports *aContext,
nsIInputStream *aStream,
PRUint32 aOffset,
PRUint32 aCount)
{
PRUint32 bytesRead = 0;
aStream->ReadSegments(ConsumeSegments, nsnull, aCount, &bytesRead);
LOG(("prefetched %u bytes [offset=%u]\n", bytesRead, aOffset));
return NS_OK;
}
NS_IMETHODIMP
nsPrefetchListener::OnStopRequest(nsIRequest *aRequest,
nsISupports *aContext,
nsresult aStatus)
{
LOG(("done prefetching [status=%x]\n", aStatus));
mService->ProcessNextURI();
return NS_OK;
}
//-----------------------------------------------------------------------------
// nsPrefetchService <public>
//-----------------------------------------------------------------------------
nsPrefetchService::nsPrefetchService()
: mQueueHead(nsnull)
, mQueueTail(nsnull)
, mStopCount(0)
, mDisabled(PR_FALSE)
{
NS_INIT_ISUPPORTS();
}
nsPrefetchService::~nsPrefetchService()
{
// cannot reach destructor if prefetch in progress (listener owns reference
// to this service)
EmptyQueue();
}
nsresult
nsPrefetchService::Init()
{
#if defined(PR_LOGGING)
if (!gPrefetchLog)
gPrefetchLog = PR_NewLogModule("nsPrefetch");
#endif
nsresult rv;
// Verify that "network.prefetch-next" preference is set to true. Skip
// this step if we encounter any errors.
nsCOMPtr<nsIPrefService> prefServ(do_GetService(kPrefServiceCID, &rv));
if (NS_SUCCEEDED(rv)) {
nsCOMPtr<nsIPrefBranch> prefs;
rv = prefServ->GetBranch(nsnull, getter_AddRefs(prefs));
if (NS_SUCCEEDED(rv)) {
PRBool enabled;
rv = prefs->GetBoolPref("network.prefetch-next", &enabled);
if (NS_SUCCEEDED(rv) && !enabled) {
LOG(("nsPrefetchService disabled via preferences\n"));
return NS_ERROR_ABORT;
}
}
}
// Observe xpcom-shutdown event
nsCOMPtr<nsIObserverService> observerServ(
do_GetService("@mozilla.org/observer-service;1", &rv));
if (NS_FAILED(rv)) return rv;
rv = observerServ->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, PR_TRUE);
if (NS_FAILED(rv)) return rv;
// Register as an observer for the document loader
nsCOMPtr<nsIWebProgress> progress(do_GetService(kDocLoaderServiceCID, &rv));
if (NS_FAILED(rv)) return rv;
return progress->AddProgressListener(this, nsIWebProgress::NOTIFY_STATE_DOCUMENT);
}
void
nsPrefetchService::ProcessNextURI()
{
nsresult rv;
nsCOMPtr<nsIURI> uri;
mCurrentChannel = nsnull;
nsCOMPtr<nsIStreamListener> listener(new nsPrefetchListener(this));
if (!listener) return;
do {
rv = DequeueURI(getter_AddRefs(uri));
if (NS_FAILED(rv)) break;
#if defined(PR_LOGGING)
if (LOG_ENABLED()) {
nsCAutoString spec;
uri->GetSpec(spec);
LOG(("ProcessNextURI [%s]\n", spec.get()));
}
#endif
//
// if opening the channel fails, then just skip to the next uri
//
rv = NS_NewChannel(getter_AddRefs(mCurrentChannel), uri, nsnull, nsnull,
nsnull, nsIRequest::LOAD_BACKGROUND);
if (NS_FAILED(rv)) continue;
rv = mCurrentChannel->AsyncOpen(listener, nsnull);
}
while (NS_FAILED(rv));
}
//-----------------------------------------------------------------------------
// nsPrefetchService <private>
//-----------------------------------------------------------------------------
nsresult
nsPrefetchService::EnqueueURI(nsIURI *aURI)
{
nsPrefetchNode *node = new nsPrefetchNode(aURI);
if (!node)
return NS_ERROR_OUT_OF_MEMORY;
if (!mQueueTail) {
mQueueHead = node;
mQueueTail = node;
}
else {
mQueueTail->mNext = node;
mQueueTail = node;
}
return NS_OK;
}
nsresult
nsPrefetchService::DequeueURI(nsIURI **aURI)
{
if (!mQueueHead)
return NS_ERROR_NOT_AVAILABLE;
// remove from the head
NS_ADDREF(*aURI = mQueueHead->mURI);
nsPrefetchNode *node = mQueueHead;
mQueueHead = mQueueHead->mNext;
delete node;
if (!mQueueHead)
mQueueTail = nsnull;
return NS_OK;
}
void
nsPrefetchService::EmptyQueue()
{
nsresult rv;
nsCOMPtr<nsIURI> uri;
do {
rv = DequeueURI(getter_AddRefs(uri));
}
while (NS_SUCCEEDED(rv));
}
void
nsPrefetchService::StartPrefetching()
{
//
// at initialization time we might miss the first DOCUMENT START
// notification, so we have to be careful to avoid letting our
// stop count go negative.
//
if (mStopCount > 0)
mStopCount--;
LOG(("StartPrefetching [stopcount=%d]\n", mStopCount));
// only start prefetching after we've received enough DOCUMENT
// STOP notifications. we do this inorder to defer prefetching
// until after all sub-frames have finished loading.
if (mStopCount == 0 && !mCurrentChannel)
ProcessNextURI();
}
void
nsPrefetchService::StopPrefetching()
{
mStopCount++;
LOG(("StopPrefetching [stopcount=%d]\n", mStopCount));
// only kill the prefetch queue if we've actually started prefetching.
if (!mCurrentChannel)
return;
mCurrentChannel->Cancel(NS_BINDING_ABORTED);
mCurrentChannel = nsnull;
EmptyQueue();
}
//-----------------------------------------------------------------------------
// nsPrefetchService::nsISupports
//-----------------------------------------------------------------------------
NS_IMPL_ISUPPORTS4(nsPrefetchService,
nsIPrefetchService,
nsIWebProgressListener,
nsIObserver,
nsISupportsWeakReference)
//-----------------------------------------------------------------------------
// nsPrefetchService::nsIPretetchService
//-----------------------------------------------------------------------------
NS_IMETHODIMP
nsPrefetchService::PrefetchURI(nsIURI *aURI)
{
nsresult rv;
#if defined(PR_LOGGING)
if (LOG_ENABLED()) {
nsCAutoString spec;
aURI->GetSpec(spec);
LOG(("PrefetchURI [%s]\n", spec.get()));
}
#endif
if (mDisabled) {
LOG(("rejected: prefetch service is disabled\n"));
return NS_ERROR_ABORT;
}
//
// XXX we should really be asking the protocol handler if it supports
// caching, so we can determine if there is any value to prefetching.
// for now, we'll only prefetch http links since we know that's the
// most common case. ignore https links since https content only goes
// into the memory cache.
//
// XXX we might want to either leverage nsIProtocolHandler::protocolFlags
// or possibly nsIRequest::loadFlags to determine if this URI should be
// prefetched.
//
PRBool isHttp;
rv = aURI->SchemeIs("http", &isHttp);
if (NS_FAILED(rv) || !isHttp) {
LOG(("rejected: URL is not of type http\n"));
return NS_ERROR_ABORT;
}
//
// skip URLs that contain query strings. these URLs are likely to result
// in documents that have zero freshness lifetimes, which we'd stop
// prefetching anyways (see nsPrefetchListener::OnStartRequest). this
// check avoids nearly doubling the load on bugzilla, for example ;-)
//
nsCOMPtr<nsIURL> url(do_QueryInterface(aURI, &rv));
if (NS_FAILED(rv)) return rv;
nsCAutoString query;
rv = url->GetQuery(query);
if (NS_FAILED(rv) || !query.IsEmpty()) {
LOG(("rejected: URL has a query string\n"));
return NS_ERROR_ABORT;
}
//
// cancel if being prefetched
//
if (mCurrentChannel) {
nsCOMPtr<nsIURI> currentURI;
mCurrentChannel->GetURI(getter_AddRefs(currentURI));
if (currentURI) {
PRBool equals;
if (NS_SUCCEEDED(currentURI->Equals(aURI, &equals)) && equals) {
LOG(("rejected: URL is already being prefetched\n"));
return NS_ERROR_ABORT;
}
}
}
//
// cancel if already on the prefetch queue
//
nsPrefetchNode *node = mQueueHead;
for (; node; node = node->mNext) {
PRBool equals;
if (NS_SUCCEEDED(node->mURI->Equals(aURI, &equals)) && equals) {
LOG(("rejected: URL is already on prefetch queue\n"));
return NS_ERROR_ABORT;
}
}
return EnqueueURI(aURI);
}
//-----------------------------------------------------------------------------
// nsPrefetchService::nsIWebProgressListener
//-----------------------------------------------------------------------------
NS_IMETHODIMP
nsPrefetchService::OnProgressChange(nsIWebProgress *aProgress,
nsIRequest *aRequest,
PRInt32 curSelfProgress,
PRInt32 maxSelfProgress,
PRInt32 curTotalProgress,
PRInt32 maxTotalProgress)
{
NS_NOTREACHED("notification excluded in AddProgressListener(...)");
return NS_OK;
}
NS_IMETHODIMP
nsPrefetchService::OnStateChange(nsIWebProgress* aWebProgress,
nsIRequest *aRequest,
PRUint32 progressStateFlags,
nsresult aStatus)
{
if (progressStateFlags & STATE_IS_DOCUMENT) {
if (progressStateFlags & STATE_STOP)
StartPrefetching();
else if (progressStateFlags & STATE_START)
StopPrefetching();
}
return NS_OK;
}
NS_IMETHODIMP
nsPrefetchService::OnLocationChange(nsIWebProgress* aWebProgress,
nsIRequest* aRequest,
nsIURI *location)
{
NS_NOTREACHED("notification excluded in AddProgressListener(...)");
return NS_OK;
}
NS_IMETHODIMP
nsPrefetchService::OnStatusChange(nsIWebProgress* aWebProgress,
nsIRequest* aRequest,
nsresult aStatus,
const PRUnichar* aMessage)
{
NS_NOTREACHED("notification excluded in AddProgressListener(...)");
return NS_OK;
}
NS_IMETHODIMP
nsPrefetchService::OnSecurityChange(nsIWebProgress *aWebProgress,
nsIRequest *aRequest,
PRUint32 state)
{
NS_NOTREACHED("notification excluded in AddProgressListener(...)");
return NS_OK;
}
//-----------------------------------------------------------------------------
// nsPrefetchService::nsIObserver
//-----------------------------------------------------------------------------
NS_IMETHODIMP
nsPrefetchService::Observe(nsISupports *aSubject,
const char *aTopic,
const PRUnichar *aData)
{
LOG(("nsPrefetchService::Observe [topic=%s]\n", aTopic));
if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
StopPrefetching();
mDisabled = PR_TRUE;
}
return NS_OK;
}
// vim: ts=4 sw=4 expandtab