/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim:set ts=4 sw=4 cindent et: */
/* ***** 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.org 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):
 *      Prasad Sunkari <prasad@medhas.org>
 *
 * 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 "nsIOService.h"
#include "nsIProtocolHandler.h"
#include "nsIFileProtocolHandler.h"
#include "nscore.h"
#include "nsIServiceManager.h"
#include "nsIURI.h"
#include "nsIStreamListener.h"
#include "prprf.h"
#include "prlog.h"
#include "nsLoadGroup.h"
#include "nsInputStreamChannel.h"
#include "nsXPIDLString.h" 
#include "nsReadableUtils.h"
#include "nsIErrorService.h" 
#include "netCore.h"
#include "nsIObserverService.h"
#include "nsIPrefService.h"
#include "nsIPrefBranch2.h"
#include "nsIPrefLocalizedString.h"
#include "nsICategoryManager.h"
#include "nsXPCOM.h"
#include "nsISupportsPrimitives.h"
#include "nsIProxiedProtocolHandler.h"
#include "nsIProxyInfo.h"
#include "nsEscape.h"
#include "nsNetCID.h"
#include "nsIRecyclingAllocator.h"
#include "nsISocketTransport.h"
#include "nsCRT.h"
#include "nsSimpleNestedURI.h"
#include "nsNetUtil.h"
#include "nsThreadUtils.h"
#include "nsIPermissionManager.h"
#include "nsTArray.h"
#include "nsIConsoleService.h"
#include "nsIUploadChannel2.h"
#include "nsXULAppAPI.h"

#include "mozilla/FunctionTimer.h"

#if defined(XP_WIN) || defined(MOZ_PLATFORM_MAEMO)
#include "nsNativeConnectionHelper.h"
#endif

#define PORT_PREF_PREFIX           "network.security.ports."
#define PORT_PREF(x)               PORT_PREF_PREFIX x
#define AUTODIAL_PREF              "network.autodial-helper.enabled"
#define MANAGE_OFFLINE_STATUS_PREF "network.manage-offline-status"

#define NECKO_BUFFER_CACHE_COUNT_PREF "network.buffer.cache.count"
#define NECKO_BUFFER_CACHE_SIZE_PREF  "network.buffer.cache.size"

#define MAX_RECURSION_COUNT 50

nsIOService* gIOService = nsnull;
static PRBool gHasWarnedUploadChannel2;

// A general port blacklist.  Connections to these ports will not be allowed unless 
// the protocol overrides.
//
// TODO: I am sure that there are more ports to be added.  
//       This cut is based on the classic mozilla codebase

PRInt16 gBadPortList[] = { 
  1,    // tcpmux          
  7,    // echo     
  9,    // discard          
  11,   // systat   
  13,   // daytime          
  15,   // netstat  
  17,   // qotd             
  19,   // chargen  
  20,   // ftp-data         
  21,   // ftp-cntl 
  22,   // ssh              
  23,   // telnet   
  25,   // smtp     
  37,   // time     
  42,   // name     
  43,   // nicname  
  53,   // domain  
  77,   // priv-rjs 
  79,   // finger   
  87,   // ttylink  
  95,   // supdup   
  101,  // hostriame
  102,  // iso-tsap 
  103,  // gppitnp  
  104,  // acr-nema 
  109,  // pop2     
  110,  // pop3     
  111,  // sunrpc   
  113,  // auth     
  115,  // sftp     
  117,  // uucp-path
  119,  // nntp     
  123,  // NTP
  135,  // loc-srv / epmap         
  139,  // netbios
  143,  // imap2  
  179,  // BGP
  389,  // ldap        
  465,  // smtp+ssl
  512,  // print / exec          
  513,  // login         
  514,  // shell         
  515,  // printer         
  526,  // tempo         
  530,  // courier        
  531,  // Chat         
  532,  // netnews        
  540,  // uucp       
  556,  // remotefs    
  563,  // nntp+ssl
  587,  //
  601,  //       
  636,  // ldap+ssl
  993,  // imap+ssl
  995,  // pop3+ssl
  2049, // nfs
  4045, // lockd
  6000, // x11        
  0,    // This MUST be zero so that we can populating the array
};

static const char kProfileChangeNetTeardownTopic[] = "profile-change-net-teardown";
static const char kProfileChangeNetRestoreTopic[] = "profile-change-net-restore";

// Necko buffer cache
nsIMemory* nsIOService::gBufferCache = nsnull;
PRUint32   nsIOService::gDefaultSegmentSize = 4096;
PRUint32   nsIOService::gDefaultSegmentCount = 24;

////////////////////////////////////////////////////////////////////////////////

nsIOService::nsIOService()
    : mOffline(PR_TRUE)
    , mOfflineForProfileChange(PR_FALSE)
    , mManageOfflineStatus(PR_TRUE)
    , mSettingOffline(PR_FALSE)
    , mSetOfflineValue(PR_FALSE)
    , mShutdown(PR_FALSE)
    , mChannelEventSinks(NS_CHANNEL_EVENT_SINK_CATEGORY)
    , mContentSniffers(NS_CONTENT_SNIFFER_CATEGORY)
    , mAutoDialEnabled(PR_FALSE)
{
}

nsresult
nsIOService::Init()
{
    NS_TIME_FUNCTION;

    nsresult rv;

    // We need to get references to the DNS service so that we can shut it
    // down later. If we wait until the nsIOService is being shut down,
    // GetService will fail at that point.

    mDNSService = do_GetService(NS_DNSSERVICE_CONTRACTID, &rv);
    if (NS_FAILED(rv)) {
        NS_WARNING("failed to get DNS service");
        return rv;
    }

    NS_TIME_FUNCTION_MARK("got DNS Service");

    // XXX hack until xpidl supports error info directly (bug 13423)
    nsCOMPtr<nsIErrorService> errorService = do_GetService(NS_ERRORSERVICE_CONTRACTID);
    if (errorService) {
        errorService->RegisterErrorStringBundle(NS_ERROR_MODULE_NETWORK, NECKO_MSGS_URL);
    }
    else
        NS_WARNING("failed to get error service");
    
    NS_TIME_FUNCTION_MARK("got Error Service");

    // setup our bad port list stuff
    for(int i=0; gBadPortList[i]; i++)
        mRestrictedPortList.AppendElement(gBadPortList[i]);

    // Further modifications to the port list come from prefs
    nsCOMPtr<nsIPrefBranch2> prefBranch;
    GetPrefBranch(getter_AddRefs(prefBranch));
    if (prefBranch) {
        prefBranch->AddObserver(PORT_PREF_PREFIX, this, PR_TRUE);
        prefBranch->AddObserver(AUTODIAL_PREF, this, PR_TRUE);
        prefBranch->AddObserver(MANAGE_OFFLINE_STATUS_PREF, this, PR_TRUE);
        PrefsChanged(prefBranch);
    }
    
    // Register for profile change notifications
    nsCOMPtr<nsIObserverService> observerService =
        mozilla::services::GetObserverService();
    if (observerService) {
        observerService->AddObserver(this, kProfileChangeNetTeardownTopic, PR_TRUE);
        observerService->AddObserver(this, kProfileChangeNetRestoreTopic, PR_TRUE);
        observerService->AddObserver(this, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID, PR_TRUE);
        observerService->AddObserver(this, NS_NETWORK_LINK_TOPIC, PR_TRUE);
    }
    else
        NS_WARNING("failed to get observer service");
        
    NS_TIME_FUNCTION_MARK("Registered observers");

    // Get the allocator ready
    if (!gBufferCache) {
        nsresult rv = NS_OK;
        nsCOMPtr<nsIRecyclingAllocator> recyclingAllocator =
            do_CreateInstance(NS_RECYCLINGALLOCATOR_CONTRACTID, &rv);

        if (NS_FAILED(rv))
            return rv;
        rv = recyclingAllocator->Init(gDefaultSegmentCount,
                                      (15 * 60), // 15 minutes
                                      "necko");

        NS_WARN_IF_FALSE(NS_SUCCEEDED(rv), "Was unable to allocate.  No gBufferCache.");
        CallQueryInterface(recyclingAllocator, &gBufferCache);
    }

    NS_TIME_FUNCTION_MARK("Set up the recycling allocator");

    gIOService = this;

    // go into managed mode if we can, and chrome process
    if (XRE_GetProcessType() == GeckoProcessType_Default)
        mNetworkLinkService = do_GetService(NS_NETWORK_LINK_SERVICE_CONTRACTID);

    if (!mNetworkLinkService)
        // We can't really determine if the machine has a usable network connection,
        // so let's cross our fingers!
        mManageOfflineStatus = PR_FALSE;

    if (mManageOfflineStatus)
        TrackNetworkLinkStatusForOffline();
    else
        SetOffline(PR_FALSE);
    
    NS_TIME_FUNCTION_MARK("Set up network link service");

    return NS_OK;
}


nsIOService::~nsIOService()
{
    gIOService = nsnull;
}

nsresult
nsIOService::InitializeSocketTransportService()
{
    NS_TIME_FUNCTION;

    nsresult rv = NS_OK;

    if (!mSocketTransportService) {
        mSocketTransportService = do_GetService(NS_SOCKETTRANSPORTSERVICE_CONTRACTID, &rv);
        if (NS_FAILED(rv)) {
            NS_WARNING("failed to get socket transport service");
        }
    }

    if (mSocketTransportService) {
        rv = mSocketTransportService->Init();
        NS_ASSERTION(NS_SUCCEEDED(rv), "socket transport service init failed");
        mSocketTransportService->SetAutodialEnabled(mAutoDialEnabled);
    }

    return rv;
}

nsIOService*
nsIOService::GetInstance() {
    if (!gIOService) {
        gIOService = new nsIOService();
        if (!gIOService)
            return nsnull;
        NS_ADDREF(gIOService);

        nsresult rv = gIOService->Init();
        if (NS_FAILED(rv)) {
            NS_RELEASE(gIOService);
            return nsnull;
        }
        return gIOService;
    }
    NS_ADDREF(gIOService);
    return gIOService;
}

NS_IMPL_THREADSAFE_ISUPPORTS5(nsIOService,
                              nsIIOService,
                              nsIIOService2,
                              nsINetUtil,
                              nsIObserver,
                              nsISupportsWeakReference)

////////////////////////////////////////////////////////////////////////////////

nsresult
nsIOService::AsyncOnChannelRedirect(nsIChannel* oldChan, nsIChannel* newChan,
                                    PRUint32 flags,
                                    nsAsyncRedirectVerifyHelper *helper)
{
    nsCOMPtr<nsIChannelEventSink> sink =
        do_GetService(NS_GLOBAL_CHANNELEVENTSINK_CONTRACTID);
    if (sink) {
        nsresult rv = helper->DelegateOnChannelRedirect(sink, oldChan,
                                                        newChan, flags);
        if (NS_FAILED(rv))
            return rv;
    }

    // Finally, our category
    const nsCOMArray<nsIChannelEventSink>& entries =
        mChannelEventSinks.GetEntries();
    PRInt32 len = entries.Count();
    for (PRInt32 i = 0; i < len; ++i) {
        nsresult rv = helper->DelegateOnChannelRedirect(entries[i], oldChan,
                                                        newChan, flags);
        if (NS_FAILED(rv))
            return rv;
    }
    return NS_OK;
}

nsresult
nsIOService::CacheProtocolHandler(const char *scheme, nsIProtocolHandler *handler)
{
    for (unsigned int i=0; i<NS_N(gScheme); i++)
    {
        if (!nsCRT::strcasecmp(scheme, gScheme[i]))
        {
            nsresult rv;
            NS_ASSERTION(!mWeakHandler[i], "Protocol handler already cached");
            // Make sure the handler supports weak references.
            nsCOMPtr<nsISupportsWeakReference> factoryPtr = do_QueryInterface(handler, &rv);
            if (!factoryPtr)
            {
                // Don't cache handlers that don't support weak reference as
                // there is real danger of a circular reference.
#ifdef DEBUG_dp
                printf("DEBUG: %s protcol handler doesn't support weak ref. Not cached.\n", scheme);
#endif /* DEBUG_dp */
                return NS_ERROR_FAILURE;
            }
            mWeakHandler[i] = do_GetWeakReference(handler);
            return NS_OK;
        }
    }
    return NS_ERROR_FAILURE;
}

nsresult
nsIOService::GetCachedProtocolHandler(const char *scheme, nsIProtocolHandler **result, PRUint32 start, PRUint32 end)
{
    PRUint32 len = end - start - 1;
    for (unsigned int i=0; i<NS_N(gScheme); i++)
    {
        if (!mWeakHandler[i])
            continue;

        // handle unterminated strings
        // start is inclusive, end is exclusive, len = end - start - 1
        if (end ? (!nsCRT::strncasecmp(scheme + start, gScheme[i], len)
                   && gScheme[i][len] == '\0')
                : (!nsCRT::strcasecmp(scheme, gScheme[i])))
        {
            return CallQueryReferent(mWeakHandler[i].get(), result);
        }
    }
    return NS_ERROR_FAILURE;
}
 
NS_IMETHODIMP
nsIOService::GetProtocolHandler(const char* scheme, nsIProtocolHandler* *result)
{
    nsresult rv;

    NS_ENSURE_ARG_POINTER(scheme);
    // XXX we may want to speed this up by introducing our own protocol 
    // scheme -> protocol handler mapping, avoiding the string manipulation
    // and service manager stuff

    rv = GetCachedProtocolHandler(scheme, result);
    if (NS_SUCCEEDED(rv))
        return rv;

    PRBool externalProtocol = PR_FALSE;
    nsCOMPtr<nsIPrefBranch2> prefBranch;
    GetPrefBranch(getter_AddRefs(prefBranch));
    if (prefBranch) {
        nsCAutoString externalProtocolPref("network.protocol-handler.external.");
        externalProtocolPref += scheme;
        rv = prefBranch->GetBoolPref(externalProtocolPref.get(), &externalProtocol);
        if (NS_FAILED(rv)) {
            externalProtocol = PR_FALSE;
        }
    }

    if (!externalProtocol) {
        nsCAutoString contractID(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX);
        contractID += scheme;
        ToLowerCase(contractID);

        rv = CallGetService(contractID.get(), result);
        if (NS_SUCCEEDED(rv)) {
            CacheProtocolHandler(scheme, *result);
            return rv;
        }

#ifdef MOZ_X11
        // check to see whether GVFS can handle this URI scheme.  if it can
        // create a nsIURI for the "scheme:", then we assume it has support for
        // the requested protocol.  otherwise, we failover to using the default
        // protocol handler.

        rv = CallGetService(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX"moz-gio",
                            result);
        if (NS_SUCCEEDED(rv)) {
            nsCAutoString spec(scheme);
            spec.Append(':');

            nsIURI *uri;
            rv = (*result)->NewURI(spec, nsnull, nsnull, &uri);
            if (NS_SUCCEEDED(rv)) {
                NS_RELEASE(uri);
                return rv;
            }

            NS_RELEASE(*result);
        }

        // check to see whether GnomeVFS can handle this URI scheme.  if it can
        // create a nsIURI for the "scheme:", then we assume it has support for
        // the requested protocol.  otherwise, we failover to using the default
        // protocol handler.

        // XXX should this be generalized into something that searches a
        // category?  (see bug 234714)

        rv = CallGetService(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX"moz-gnomevfs",
                            result);
        if (NS_SUCCEEDED(rv)) {
            nsCAutoString spec(scheme);
            spec.Append(':');

            nsIURI *uri;
            rv = (*result)->NewURI(spec, nsnull, nsnull, &uri);
            if (NS_SUCCEEDED(rv)) {
                NS_RELEASE(uri);
                return rv;
            }

            NS_RELEASE(*result);
        }
#endif
    }

    // Okay we don't have a protocol handler to handle this url type, so use
    // the default protocol handler.  This will cause urls to get dispatched
    // out to the OS ('cause we can't do anything with them) when we try to
    // read from a channel created by the default protocol handler.

    rv = CallGetService(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX"default",
                        result);
    if (NS_FAILED(rv))
        return NS_ERROR_UNKNOWN_PROTOCOL;

    return rv;
}

NS_IMETHODIMP
nsIOService::ExtractScheme(const nsACString &inURI, nsACString &scheme)
{
    return net_ExtractURLScheme(inURI, nsnull, nsnull, &scheme);
}

NS_IMETHODIMP 
nsIOService::GetProtocolFlags(const char* scheme, PRUint32 *flags)
{
    nsCOMPtr<nsIProtocolHandler> handler;
    nsresult rv = GetProtocolHandler(scheme, getter_AddRefs(handler));
    if (NS_FAILED(rv)) return rv;

    rv = handler->GetProtocolFlags(flags);
    return rv;
}

class AutoIncrement
{
    public:
        AutoIncrement(PRUint32 *var) : mVar(var)
        {
            ++*var;
        }
        ~AutoIncrement()
        {
            --*mVar;
        }
    private:
        PRUint32 *mVar;
};

nsresult
nsIOService::NewURI(const nsACString &aSpec, const char *aCharset, nsIURI *aBaseURI, nsIURI **result)
{
    NS_ASSERTION(NS_IsMainThread(), "wrong thread");

    static PRUint32 recursionCount = 0;
    if (recursionCount >= MAX_RECURSION_COUNT)
        return NS_ERROR_MALFORMED_URI;
    AutoIncrement inc(&recursionCount);

    nsCAutoString scheme;
    nsresult rv = ExtractScheme(aSpec, scheme);
    if (NS_FAILED(rv)) {
        // then aSpec is relative
        if (!aBaseURI)
            return NS_ERROR_MALFORMED_URI;

        rv = aBaseURI->GetScheme(scheme);
        if (NS_FAILED(rv)) return rv;
    }

    // now get the handler for this scheme
    nsCOMPtr<nsIProtocolHandler> handler;
    rv = GetProtocolHandler(scheme.get(), getter_AddRefs(handler));
    if (NS_FAILED(rv)) return rv;

    return handler->NewURI(aSpec, aCharset, aBaseURI, result);
}


NS_IMETHODIMP 
nsIOService::NewFileURI(nsIFile *file, nsIURI **result)
{
    nsresult rv;
    NS_ENSURE_ARG_POINTER(file);

    nsCOMPtr<nsIProtocolHandler> handler;

    rv = GetProtocolHandler("file", getter_AddRefs(handler));
    if (NS_FAILED(rv)) return rv;

    nsCOMPtr<nsIFileProtocolHandler> fileHandler( do_QueryInterface(handler, &rv) );
    if (NS_FAILED(rv)) return rv;
    
    return fileHandler->NewFileURI(file, result);
}

NS_IMETHODIMP
nsIOService::NewChannelFromURI(nsIURI *aURI, nsIChannel **result)
{
    return NewChannelFromURIWithProxyFlags(aURI, nsnull, 0, result);
}

NS_IMETHODIMP
nsIOService::NewChannelFromURIWithProxyFlags(nsIURI *aURI,
                                             nsIURI *aProxyURI,
                                             PRUint32 proxyFlags,
                                             nsIChannel **result)
{
    nsresult rv;
    NS_ENSURE_ARG_POINTER(aURI);

    nsCAutoString scheme;
    rv = aURI->GetScheme(scheme);
    if (NS_FAILED(rv))
        return rv;

    nsCOMPtr<nsIProtocolHandler> handler;
    rv = GetProtocolHandler(scheme.get(), getter_AddRefs(handler));
    if (NS_FAILED(rv))
        return rv;

    PRUint32 protoFlags;
    rv = handler->GetProtocolFlags(&protoFlags);
    if (NS_FAILED(rv))
        return rv;

    // Talk to the PPS if the protocol handler allows proxying.  Otherwise,
    // skip this step.  This allows us to lazily load the PPS at startup.
    if (protoFlags & nsIProtocolHandler::ALLOWS_PROXY) {
        nsCOMPtr<nsIProxyInfo> pi;
        if (!mProxyService) {
            mProxyService = do_GetService(NS_PROTOCOLPROXYSERVICE_CONTRACTID);
            if (!mProxyService)
                NS_WARNING("failed to get protocol proxy service");
        }
        if (mProxyService) {
            rv = mProxyService->Resolve(aProxyURI ? aProxyURI : aURI,
                                        proxyFlags, getter_AddRefs(pi));
            if (NS_FAILED(rv))
                pi = nsnull;
        }
        if (pi) {
            nsCAutoString type;
            if (NS_SUCCEEDED(pi->GetType(type)) && type.EqualsLiteral("http")) {
                // we are going to proxy this channel using an http proxy
                rv = GetProtocolHandler("http", getter_AddRefs(handler));
                if (NS_FAILED(rv))
                    return rv;
            }
            nsCOMPtr<nsIProxiedProtocolHandler> pph = do_QueryInterface(handler);
            if (pph)
                return pph->NewProxiedChannel(aURI, pi, result);
        }
    }

    rv = handler->NewChannel(aURI, result);
    NS_ENSURE_SUCCESS(rv, rv);

    // Some extensions override the http protocol handler and provide their own
    // implementation. The channels returned from that implementation doesn't
    // seem to always implement the nsIUploadChannel2 interface, presumably
    // because it's a new interface.
    // Eventually we should remove this and simply require that http channels
    // implement the new interface.
    // See bug 529041
    if (!gHasWarnedUploadChannel2 && scheme.EqualsLiteral("http")) {
        nsCOMPtr<nsIUploadChannel2> uploadChannel2 = do_QueryInterface(*result);
        if (!uploadChannel2) {
            nsCOMPtr<nsIConsoleService> consoleService =
                do_GetService(NS_CONSOLESERVICE_CONTRACTID);
            if (consoleService) {
                consoleService->LogStringMessage(NS_LITERAL_STRING(
                    "Http channel implementation doesn't support nsIUploadChannel2. An extension has supplied a non-functional http protocol handler. This will break behavior and in future releases not work at all."
                                                                   ).get());
            }
            gHasWarnedUploadChannel2 = PR_TRUE;
        }
    }

    return NS_OK;
}

NS_IMETHODIMP
nsIOService::NewChannel(const nsACString &aSpec, const char *aCharset, nsIURI *aBaseURI, nsIChannel **result)
{
    nsresult rv;
    nsCOMPtr<nsIURI> uri;
    rv = NewURI(aSpec, aCharset, aBaseURI, getter_AddRefs(uri));
    if (NS_FAILED(rv)) return rv;

    return NewChannelFromURI(uri, result);
}

PRBool
nsIOService::IsLinkUp()
{
    if (!mNetworkLinkService) {
        // We cannot decide, assume the link is up
        return PR_TRUE;
    }

    PRBool isLinkUp;
    nsresult rv;
    rv = mNetworkLinkService->GetIsLinkUp(&isLinkUp);
    if (NS_FAILED(rv)) {
        return PR_TRUE;
    }

    return isLinkUp;
}

NS_IMETHODIMP
nsIOService::GetOffline(PRBool *offline)
{
    *offline = mOffline;
    return NS_OK;
}

NS_IMETHODIMP
nsIOService::SetOffline(PRBool offline)
{
    // When someone wants to go online (!offline) after we got XPCOM shutdown
    // throw ERROR_NOT_AVAILABLE to prevent return to online state.
    if (mShutdown && !offline)
        return NS_ERROR_NOT_AVAILABLE;

    // SetOffline() may re-enter while it's shutting down services.
    // If that happens, save the most recent value and it will be
    // processed when the first SetOffline() call is done bringing
    // down the service.
    mSetOfflineValue = offline;
    if (mSettingOffline) {
        return NS_OK;
    }

    mSettingOffline = PR_TRUE;

    nsCOMPtr<nsIObserverService> observerService =
        mozilla::services::GetObserverService();

    NS_ASSERTION(observerService, "The observer service should not be null");

    if (XRE_GetProcessType() == GeckoProcessType_Default) {
        if (observerService) {
            (void)observerService->NotifyObservers(nsnull,
                NS_IPC_IOSERVICE_SET_OFFLINE_TOPIC, offline ? 
                NS_LITERAL_STRING("true").get() :
                NS_LITERAL_STRING("false").get());
        }
    }

    while (mSetOfflineValue != mOffline) {
        offline = mSetOfflineValue;

        nsresult rv;
        if (offline && !mOffline) {
            NS_NAMED_LITERAL_STRING(offlineString, NS_IOSERVICE_OFFLINE);
            mOffline = PR_TRUE; // indicate we're trying to shutdown

            // don't care if notification fails
            // this allows users to attempt a little cleanup before dns and socket transport are shut down.
            if (observerService)
                observerService->NotifyObservers(static_cast<nsIIOService *>(this),
                                                 NS_IOSERVICE_GOING_OFFLINE_TOPIC,
                                                 offlineString.get());

            // be sure to try and shutdown both (even if the first fails)...
            // shutdown dns service first, because it has callbacks for socket transport
            if (mDNSService) {
                rv = mDNSService->Shutdown();
                NS_ASSERTION(NS_SUCCEEDED(rv), "DNS service shutdown failed");
            }
            if (mSocketTransportService) {
                rv = mSocketTransportService->Shutdown();
                NS_ASSERTION(NS_SUCCEEDED(rv), "socket transport service shutdown failed");
            }

            // don't care if notification fails
            if (observerService)
                observerService->NotifyObservers(static_cast<nsIIOService *>(this),
                                                 NS_IOSERVICE_OFFLINE_STATUS_TOPIC,
                                                 offlineString.get());
        }
        else if (!offline && mOffline) {
            // go online
            if (mDNSService) {
                rv = mDNSService->Init();
                NS_ASSERTION(NS_SUCCEEDED(rv), "DNS service init failed");
            }
            InitializeSocketTransportService();
            mOffline = PR_FALSE;    // indicate success only AFTER we've
                                    // brought up the services

            // trigger a PAC reload when we come back online
            if (mProxyService)
                mProxyService->ReloadPAC();

            // don't care if notification fails
            if (observerService)
                observerService->NotifyObservers(static_cast<nsIIOService *>(this),
                                                 NS_IOSERVICE_OFFLINE_STATUS_TOPIC,
                                                 NS_LITERAL_STRING(NS_IOSERVICE_ONLINE).get());
        }
    }

    mSettingOffline = PR_FALSE;

    return NS_OK;
}


NS_IMETHODIMP
nsIOService::AllowPort(PRInt32 inPort, const char *scheme, PRBool *_retval)
{
    PRInt16 port = inPort;
    if (port == -1) {
        *_retval = PR_TRUE;
        return NS_OK;
    }
        
    // first check to see if the port is in our blacklist:
    PRInt32 badPortListCnt = mRestrictedPortList.Length();
    for (int i=0; i<badPortListCnt; i++)
    {
        if (port == mRestrictedPortList[i])
        {
            *_retval = PR_FALSE;

            // check to see if the protocol wants to override
            if (!scheme)
                return NS_OK;
            
            nsCOMPtr<nsIProtocolHandler> handler;
            nsresult rv = GetProtocolHandler(scheme, getter_AddRefs(handler));
            if (NS_FAILED(rv)) return rv;

            // let the protocol handler decide
            return handler->AllowPort(port, scheme, _retval);
        }
    }

    *_retval = PR_TRUE;
    return NS_OK;
}

////////////////////////////////////////////////////////////////////////////////

void
nsIOService::PrefsChanged(nsIPrefBranch *prefs, const char *pref)
{
    if (!prefs) return;

    // Look for extra ports to block
    if (!pref || strcmp(pref, PORT_PREF("banned")) == 0)
        ParsePortList(prefs, PORT_PREF("banned"), PR_FALSE);

    // ...as well as previous blocks to remove.
    if (!pref || strcmp(pref, PORT_PREF("banned.override")) == 0)
        ParsePortList(prefs, PORT_PREF("banned.override"), PR_TRUE);

    if (!pref || strcmp(pref, AUTODIAL_PREF) == 0) {
        PRBool enableAutodial = PR_FALSE;
        nsresult rv = prefs->GetBoolPref(AUTODIAL_PREF, &enableAutodial);
        // If pref not found, default to disabled.
        mAutoDialEnabled = enableAutodial;
        if (NS_SUCCEEDED(rv)) {
            if (mSocketTransportService)
                mSocketTransportService->SetAutodialEnabled(enableAutodial);
        }
    }

    if (!pref || strcmp(pref, MANAGE_OFFLINE_STATUS_PREF) == 0) {
        PRBool manage;
        if (NS_SUCCEEDED(prefs->GetBoolPref(MANAGE_OFFLINE_STATUS_PREF,
                                            &manage)))
            SetManageOfflineStatus(manage);
    }

    if (!pref || strcmp(pref, NECKO_BUFFER_CACHE_COUNT_PREF) == 0) {
        PRInt32 count;
        if (NS_SUCCEEDED(prefs->GetIntPref(NECKO_BUFFER_CACHE_COUNT_PREF,
                                           &count)))
            /* check for bogus values and default if we find such a value */
            if (count > 0)
                gDefaultSegmentCount = count;
    }
    
    if (!pref || strcmp(pref, NECKO_BUFFER_CACHE_SIZE_PREF) == 0) {
        PRInt32 size;
        if (NS_SUCCEEDED(prefs->GetIntPref(NECKO_BUFFER_CACHE_SIZE_PREF,
                                           &size)))
            /* check for bogus values and default if we find such a value
             * the upper limit here is arbitrary. having a 1mb segment size
             * is pretty crazy.  if you remove this, consider adding some
             * integer rollover test.
             */
            if (size > 0 && size < 1024*1024)
                gDefaultSegmentSize = size;
        NS_WARN_IF_FALSE( (!(size & (size - 1))) , "network buffer cache size is not a power of 2!");
    }
}

void
nsIOService::ParsePortList(nsIPrefBranch *prefBranch, const char *pref, PRBool remove)
{
    nsXPIDLCString portList;

    // Get a pref string and chop it up into a list of ports.
    prefBranch->GetCharPref(pref, getter_Copies(portList));
    if (portList) {
        nsTArray<nsCString> portListArray;
        ParseString(portList, ',', portListArray);
        PRUint32 index;
        for (index=0; index < portListArray.Length(); index++) {
            portListArray[index].StripWhitespace();
            PRInt32 aErrorCode, portBegin, portEnd;

            if (PR_sscanf(portListArray[index].get(), "%d-%d", &portBegin, &portEnd) == 2) {
               if ((portBegin < 65536) && (portEnd < 65536)) {
                   PRInt32 curPort;
                   if (remove) {
                        for (curPort=portBegin; curPort <= portEnd; curPort++)
                            mRestrictedPortList.RemoveElement(curPort);
                   } else {
                        for (curPort=portBegin; curPort <= portEnd; curPort++)
                            mRestrictedPortList.AppendElement(curPort);
                   }
               }
            } else {
               PRInt32 port = portListArray[index].ToInteger(&aErrorCode);
               if (NS_SUCCEEDED(aErrorCode) && port < 65536) {
                   if (remove)
                       mRestrictedPortList.RemoveElement(port);
                   else
                       mRestrictedPortList.AppendElement(port);
               }
            }

        }
    }
}

void
nsIOService::GetPrefBranch(nsIPrefBranch2 **result)
{
    *result = nsnull;
    CallGetService(NS_PREFSERVICE_CONTRACTID, result);
}

// nsIObserver interface
NS_IMETHODIMP
nsIOService::Observe(nsISupports *subject,
                     const char *topic,
                     const PRUnichar *data)
{
    if (!strcmp(topic, NS_PREFBRANCH_PREFCHANGE_TOPIC_ID)) {
        nsCOMPtr<nsIPrefBranch> prefBranch = do_QueryInterface(subject);
        if (prefBranch)
            PrefsChanged(prefBranch, NS_ConvertUTF16toUTF8(data).get());
    }
    else if (!strcmp(topic, kProfileChangeNetTeardownTopic)) {
        if (!mOffline) {
            SetOffline(PR_TRUE);
            mOfflineForProfileChange = PR_TRUE;
        }
    }
    else if (!strcmp(topic, kProfileChangeNetRestoreTopic)) {
        if (mOfflineForProfileChange) {
            mOfflineForProfileChange = PR_FALSE;
            if (!mManageOfflineStatus ||
                NS_FAILED(TrackNetworkLinkStatusForOffline())) {
                SetOffline(PR_FALSE);
            }
        } 
    }
    else if (!strcmp(topic, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID)) {
        // Remember we passed XPCOM shutdown notification to prevent any
        // changes of the offline status from now. We must not allow going
        // online after this point.
        mShutdown = PR_TRUE;

        SetOffline(PR_TRUE);

        // Break circular reference.
        mProxyService = nsnull;
    }
    else if (!strcmp(topic, NS_NETWORK_LINK_TOPIC)) {
        if (!mOfflineForProfileChange && mManageOfflineStatus) {
            TrackNetworkLinkStatusForOffline();
        }
    }
    
    return NS_OK;
}

// nsINetUtil interface
NS_IMETHODIMP
nsIOService::ParseContentType(const nsACString &aTypeHeader,
                              nsACString &aCharset,
                              PRBool *aHadCharset,
                              nsACString &aContentType)
{
    net_ParseContentType(aTypeHeader, aContentType, aCharset, aHadCharset);
    return NS_OK;
}

NS_IMETHODIMP
nsIOService::ProtocolHasFlags(nsIURI   *uri,
                              PRUint32  flags,
                              PRBool   *result)
{
    NS_ENSURE_ARG(uri);

    *result = PR_FALSE;
    nsCAutoString scheme;
    nsresult rv = uri->GetScheme(scheme);
    NS_ENSURE_SUCCESS(rv, rv);
  
    PRUint32 protocolFlags;
    rv = GetProtocolFlags(scheme.get(), &protocolFlags);

    if (NS_SUCCEEDED(rv)) {
        *result = (protocolFlags & flags) == flags;
    }
  
    return rv;
}

NS_IMETHODIMP
nsIOService::URIChainHasFlags(nsIURI   *uri,
                              PRUint32  flags,
                              PRBool   *result)
{
    nsresult rv = ProtocolHasFlags(uri, flags, result);
    NS_ENSURE_SUCCESS(rv, rv);

    if (*result) {
        return rv;
    }

    // Dig deeper into the chain.  Note that this is not a do/while loop to
    // avoid the extra addref/release on |uri| in the common (non-nested) case.
    nsCOMPtr<nsINestedURI> nestedURI = do_QueryInterface(uri);
    while (nestedURI) {
        nsCOMPtr<nsIURI> innerURI;
        rv = nestedURI->GetInnerURI(getter_AddRefs(innerURI));
        NS_ENSURE_SUCCESS(rv, rv);

        rv = ProtocolHasFlags(innerURI, flags, result);

        if (*result) {
            return rv;
        }

        nestedURI = do_QueryInterface(innerURI);
    }

    return rv;
}

NS_IMETHODIMP
nsIOService::ToImmutableURI(nsIURI* uri, nsIURI** result)
{
    if (!uri) {
        *result = nsnull;
        return NS_OK;
    }

    nsresult rv = NS_EnsureSafeToReturn(uri, result);
    NS_ENSURE_SUCCESS(rv, rv);

    NS_TryToSetImmutable(*result);
    return NS_OK;
}

NS_IMETHODIMP
nsIOService::NewSimpleNestedURI(nsIURI* aURI, nsIURI** aResult)
{
    NS_ENSURE_ARG(aURI);

    nsCOMPtr<nsIURI> safeURI;
    nsresult rv = NS_EnsureSafeToReturn(aURI, getter_AddRefs(safeURI));
    NS_ENSURE_SUCCESS(rv, rv);

    NS_IF_ADDREF(*aResult = new nsSimpleNestedURI(safeURI));
    return *aResult ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
}

NS_IMETHODIMP
nsIOService::SetManageOfflineStatus(PRBool aManage) {
    PRBool wasManaged = mManageOfflineStatus;
    mManageOfflineStatus = aManage;
    if (mManageOfflineStatus && !wasManaged)
        return TrackNetworkLinkStatusForOffline();
    return NS_OK;
}

NS_IMETHODIMP
nsIOService::GetManageOfflineStatus(PRBool* aManage) {
    *aManage = mManageOfflineStatus;
    return NS_OK;
}

nsresult
nsIOService::TrackNetworkLinkStatusForOffline()
{
    NS_ASSERTION(mManageOfflineStatus,
                 "Don't call this unless we're managing the offline status");
    if (!mNetworkLinkService)
        return NS_ERROR_FAILURE;

    if (mShutdown)
        return NS_ERROR_NOT_AVAILABLE;
  
    // check to make sure this won't collide with Autodial
    if (mSocketTransportService) {
        PRBool autodialEnabled = PR_FALSE;
        mSocketTransportService->GetAutodialEnabled(&autodialEnabled);
        // If autodialing-on-link-down is enabled, check if the OS auto dial 
        // option is set to always autodial. If so, then we are 
        // always up for the purposes of offline management.
        if (autodialEnabled) {
#if defined(XP_WIN) || defined(MOZ_PLATFORM_MAEMO)
            // On Windows and Maemo (libconic) we should first check with the OS
            // to see if autodial is enabled.  If it is enabled then we are
            // allowed to manage the offline state.
            if(nsNativeConnectionHelper::IsAutodialEnabled()) 
                return SetOffline(PR_FALSE);
#else
            return SetOffline(PR_FALSE);
#endif
        }
    }

    PRBool isUp;
    nsresult rv = mNetworkLinkService->GetIsLinkUp(&isUp);
    NS_ENSURE_SUCCESS(rv, rv);
    return SetOffline(!isUp);
}

NS_IMETHODIMP
nsIOService::EscapeString(const nsACString& aString,
                          PRUint32 aEscapeType,
                          nsACString& aResult)
{
  NS_ENSURE_ARG_RANGE(aEscapeType, 0, 4);

  nsCAutoString stringCopy(aString);
  nsCString result;

  if (!NS_Escape(stringCopy, result, (nsEscapeMask) aEscapeType))
    return NS_ERROR_OUT_OF_MEMORY;

  aResult.Assign(result);

  return NS_OK;
}

NS_IMETHODIMP 
nsIOService::EscapeURL(const nsACString &aStr, 
                       PRUint32 aFlags, nsACString &aResult)
{
  aResult.Truncate();
  NS_EscapeURL(aStr.BeginReading(), aStr.Length(), 
               aFlags | esc_AlwaysCopy, aResult);
  return NS_OK;
}

NS_IMETHODIMP 
nsIOService::UnescapeString(const nsACString &aStr, 
                            PRUint32 aFlags, nsACString &aResult)
{
  aResult.Truncate();
  NS_UnescapeURL(aStr.BeginReading(), aStr.Length(), 
                 aFlags | esc_AlwaysCopy, aResult);
  return NS_OK;
}

NS_IMETHODIMP
nsIOService::ExtractCharsetFromContentType(const nsACString &aTypeHeader,
                                           nsACString &aCharset,
                                           PRInt32 *aCharsetStart,
                                           PRInt32 *aCharsetEnd,
                                           PRBool *aHadCharset)
{
    nsCAutoString ignored;
    net_ParseContentType(aTypeHeader, ignored, aCharset, aHadCharset,
                         aCharsetStart, aCharsetEnd);
    if (*aHadCharset && *aCharsetStart == *aCharsetEnd) {
        *aHadCharset = PR_FALSE;
    }
    return NS_OK;
}