/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */

#include "nsAppStartup.h"

#include "nsIAppShellService.h"
#include "nsPIDOMWindow.h"
#include "nsIInterfaceRequestor.h"
#include "nsIFile.h"
#include "nsIObserverService.h"
#include "nsIPrefBranch.h"
#include "nsIPrefService.h"
#include "nsIProfileChangeStatus.h"
#include "nsIPromptService.h"
#include "nsIStringBundle.h"
#include "nsISupportsPrimitives.h"
#include "nsIWebBrowserChrome.h"
#include "nsIWindowMediator.h"
#include "nsIWindowWatcher.h"
#include "nsIXULRuntime.h"
#include "nsIXULWindow.h"
#include "nsNativeCharsetUtils.h"
#include "nsThreadUtils.h"
#include "nsAutoPtr.h"
#include "nsStringGlue.h"
#include "mozilla/Preferences.h"

#include "prprf.h"
#include "nsCRT.h"
#include "nsIInterfaceRequestorUtils.h"
#include "nsWidgetsCID.h"
#include "nsAppShellCID.h"
#include "nsXPCOMCIDInternal.h"
#include "mozilla/Services.h"
#include "nsIXPConnect.h"
#include "jsapi.h"
#include "prenv.h"
#include "nsAppDirectoryServiceDefs.h"
#include "mozilla/mozPoisonWrite.h"

#if defined(XP_WIN)
#include <windows.h>
// windows.h can go to hell 
#undef GetStartupInfo
#elif defined(XP_UNIX)
#include <unistd.h>
#include <sys/syscall.h>
#endif

#if defined(XP_MACOSX) || defined(__DragonFly__) || defined(__FreeBSD__) \
  || defined(__NetBSD__) || defined(__OpenBSD__)
#include <sys/param.h>
#include <sys/sysctl.h>
#endif

#if defined(__DragonFly__) || defined(__FreeBSD__)
#include <sys/user.h>
#endif

#include "mozilla/Telemetry.h"
#include "mozilla/StartupTimeline.h"

#if defined(__NetBSD__)
#undef KERN_PROC
#define KERN_PROC KERN_PROC2
#define KINFO_PROC struct kinfo_proc2
#else
#define KINFO_PROC struct kinfo_proc
#endif

#if defined(XP_MACOSX)
#define KP_START_SEC kp_proc.p_un.__p_starttime.tv_sec
#define KP_START_USEC kp_proc.p_un.__p_starttime.tv_usec
#elif defined(__DragonFly__)
#define KP_START_SEC kp_start.tv_sec
#define KP_START_USEC kp_start.tv_usec
#elif defined(__FreeBSD__)
#define KP_START_SEC ki_start.tv_sec
#define KP_START_USEC ki_start.tv_usec
#else
#define KP_START_SEC p_ustart_sec
#define KP_START_USEC p_ustart_usec
#endif

static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);

#define kPrefLastSuccess "toolkit.startup.last_success"
#define kPrefMaxResumedCrashes "toolkit.startup.max_resumed_crashes"
#define kPrefRecentCrashes "toolkit.startup.recent_crashes"

#if defined(XP_WIN)
#include "mozilla/perfprobe.h"
/**
 * Events sent to the system for profiling purposes
 */
//Keep them syncronized with the .mof file

//Process-wide GUID, used by the OS to differentiate sources
// {509962E0-406B-46F4-99BA-5A009F8D2225}
//Keep it synchronized with the .mof file
#define NS_APPLICATION_TRACING_CID \
  { 0x509962E0, 0x406B, 0x46F4, \
  { 0x99, 0xBA, 0x5A, 0x00, 0x9F, 0x8D, 0x22, 0x25} }

//Event-specific GUIDs, used by the OS to differentiate events
// {A3DA04E0-57D7-482A-A1C1-61DA5F95BACB}
#define NS_PLACES_INIT_COMPLETE_EVENT_CID \
  { 0xA3DA04E0, 0x57D7, 0x482A, \
  { 0xA1, 0xC1, 0x61, 0xDA, 0x5F, 0x95, 0xBA, 0xCB} }
// {917B96B1-ECAD-4DAB-A760-8D49027748AE}
#define NS_SESSION_STORE_WINDOW_RESTORED_EVENT_CID \
  { 0x917B96B1, 0xECAD, 0x4DAB, \
  { 0xA7, 0x60, 0x8D, 0x49, 0x02, 0x77, 0x48, 0xAE} }
// {26D1E091-0AE7-4F49-A554-4214445C505C}
#define NS_XPCOM_SHUTDOWN_EVENT_CID \
  { 0x26D1E091, 0x0AE7, 0x4F49, \
  { 0xA5, 0x54, 0x42, 0x14, 0x44, 0x5C, 0x50, 0x5C} }

static NS_DEFINE_CID(kApplicationTracingCID,
  NS_APPLICATION_TRACING_CID);
static NS_DEFINE_CID(kPlacesInitCompleteCID,
  NS_PLACES_INIT_COMPLETE_EVENT_CID);
static NS_DEFINE_CID(kSessionStoreWindowRestoredCID,
  NS_SESSION_STORE_WINDOW_RESTORED_EVENT_CID);
static NS_DEFINE_CID(kXPCOMShutdownCID,
  NS_XPCOM_SHUTDOWN_EVENT_CID);  
#endif //defined(XP_WIN)

using namespace mozilla;

uint32_t gRestartMode = 0;

class nsAppExitEvent : public nsRunnable {
private:
  nsRefPtr<nsAppStartup> mService;

public:
  nsAppExitEvent(nsAppStartup *service) : mService(service) {}

  NS_IMETHOD Run() {
    // Tell the appshell to exit
    mService->mAppShell->Exit();

    // We're done "shutting down".
    mService->mShuttingDown = false;
    mService->mRunning = false;
    return NS_OK;
  }
};

//
// nsAppStartup
//

nsAppStartup::nsAppStartup() :
  mConsiderQuitStopper(0),
  mRunning(false),
  mShuttingDown(false),
  mAttemptingQuit(false),
  mRestart(false),
  mInterrupted(false),
  mIsSafeModeNecessary(false),
  mStartupCrashTrackingEnded(false),
  mCachedShutdownTime(false),
  mLastShutdownTime(0)
{ }


nsresult
nsAppStartup::Init()
{
  nsresult rv;

  // Create widget application shell
  mAppShell = do_GetService(kAppShellCID, &rv);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIObserverService> os =
    mozilla::services::GetObserverService();
  if (!os)
    return NS_ERROR_FAILURE;

  os->AddObserver(this, "quit-application-forced", true);
  os->AddObserver(this, "sessionstore-windows-restored", true);
  os->AddObserver(this, "profile-change-teardown", true);
  os->AddObserver(this, "xul-window-registered", true);
  os->AddObserver(this, "xul-window-destroyed", true);

#if defined(XP_WIN)
  os->AddObserver(this, "xpcom-shutdown", true);
  os->AddObserver(this, "places-init-complete", true);
  // This last event is only interesting to us for xperf-based measures

  // Initialize interaction with profiler
  mProbesManager =
    new ProbeManager(
                     kApplicationTracingCID,
                     NS_LITERAL_CSTRING("Application startup probe"));
  // Note: The operation is meant mostly for in-house profiling.
  // Therefore, we do not warn if probes manager cannot be initialized

  if (mProbesManager) {
    mPlacesInitCompleteProbe =
      mProbesManager->
      GetProbe(kPlacesInitCompleteCID,
               NS_LITERAL_CSTRING("places-init-complete"));
    NS_WARN_IF_FALSE(mPlacesInitCompleteProbe,
                     "Cannot initialize probe 'places-init-complete'");

    mSessionWindowRestoredProbe =
      mProbesManager->
      GetProbe(kSessionStoreWindowRestoredCID,
               NS_LITERAL_CSTRING("sessionstore-windows-restored"));
    NS_WARN_IF_FALSE(mSessionWindowRestoredProbe,
                     "Cannot initialize probe 'sessionstore-windows-restored'");
                     
    mXPCOMShutdownProbe =
      mProbesManager->
      GetProbe(kXPCOMShutdownCID,
               NS_LITERAL_CSTRING("xpcom-shutdown"));
    NS_WARN_IF_FALSE(mXPCOMShutdownProbe,
                     "Cannot initialize probe 'xpcom-shutdown'");

    rv = mProbesManager->StartSession();
    NS_WARN_IF_FALSE(NS_SUCCEEDED(rv),
                     "Cannot initialize system probe manager");
  }
#endif //defined(XP_WIN)

  return NS_OK;
}


//
// nsAppStartup->nsISupports
//

NS_IMPL_THREADSAFE_ISUPPORTS5(nsAppStartup,
                              nsIAppStartup,
                              nsIWindowCreator,
                              nsIWindowCreator2,
                              nsIObserver,
                              nsISupportsWeakReference)


//
// nsAppStartup->nsIAppStartup
//

NS_IMETHODIMP
nsAppStartup::CreateHiddenWindow()
{
  nsCOMPtr<nsIAppShellService> appShellService
    (do_GetService(NS_APPSHELLSERVICE_CONTRACTID));
  NS_ENSURE_TRUE(appShellService, NS_ERROR_FAILURE);

  return appShellService->CreateHiddenWindow();
}


NS_IMETHODIMP
nsAppStartup::DestroyHiddenWindow()
{
  nsCOMPtr<nsIAppShellService> appShellService
    (do_GetService(NS_APPSHELLSERVICE_CONTRACTID));
  NS_ENSURE_TRUE(appShellService, NS_ERROR_FAILURE);

  return appShellService->DestroyHiddenWindow();
}

NS_IMETHODIMP
nsAppStartup::Run(void)
{
  NS_ASSERTION(!mRunning, "Reentrant appstartup->Run()");

  // If we have no windows open and no explicit calls to
  // enterLastWindowClosingSurvivalArea, or somebody has explicitly called
  // quit, don't bother running the event loop which would probably leave us
  // with a zombie process.

  if (!mShuttingDown && mConsiderQuitStopper != 0) {
#ifdef XP_MACOSX
    EnterLastWindowClosingSurvivalArea();
#endif

    mRunning = true;

    nsresult rv = mAppShell->Run();
    if (NS_FAILED(rv))
      return rv;
  }

  return mRestart ? NS_SUCCESS_RESTART_APP : NS_OK;
}

static TimeStamp gRecordedShutdownStartTime;
static bool gAlreadyFreedShutdownTimeFileName = false;
static char *gRecordedShutdownTimeFileName = NULL;

static char *
GetShutdownTimeFileName()
{
  if (gAlreadyFreedShutdownTimeFileName) {
    return NULL;
  }

  if (!gRecordedShutdownTimeFileName) {
    nsCOMPtr<nsIFile> mozFile;
    NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR, getter_AddRefs(mozFile));
    if (!mozFile)
      return NULL;

    mozFile->AppendNative(NS_LITERAL_CSTRING("Telemetry.ShutdownTime.txt"));
    nsAutoCString nativePath;
    nsresult rv = mozFile->GetNativePath(nativePath);
    if (!NS_SUCCEEDED(rv))
      return NULL;

    gRecordedShutdownTimeFileName = PL_strdup(nativePath.get());
  }

  return gRecordedShutdownTimeFileName;
}

static void
RecordShutdownStartTimeStamp() {
  if (!Telemetry::CanRecord())
    return;

  gRecordedShutdownStartTime = TimeStamp::Now();

  GetShutdownTimeFileName();
}

namespace mozilla {
void
RecordShutdownEndTimeStamp() {
  if (!gRecordedShutdownTimeFileName || gAlreadyFreedShutdownTimeFileName)
    return;

  nsCString name(gRecordedShutdownTimeFileName);
  PL_strfree(gRecordedShutdownTimeFileName);
  gRecordedShutdownTimeFileName = NULL;
  gAlreadyFreedShutdownTimeFileName = true;

  nsCString tmpName = name;
  tmpName += ".tmp";
  FILE *f = fopen(tmpName.get(), "w");
  if (!f)
    return;
  // On a normal release build this should be called just before
  // calling _exit, but on a debug build or when the user forces a full
  // shutdown this is called as late as possible, so we have to
  // white list this write as write poisoning will be enabled.
  int fd = fileno(f);
  MozillaRegisterDebugFD(fd);

  TimeStamp now = TimeStamp::Now();
  MOZ_ASSERT(now >= gRecordedShutdownStartTime);
  TimeDuration diff = now - gRecordedShutdownStartTime;
  uint32_t diff2 = diff.ToMilliseconds();
  int written = fprintf(f, "%d\n", diff2);
  MozillaUnRegisterDebugFILE(f);
  int rv = fclose(f);
  if (written < 0 || rv != 0) {
    PR_Delete(tmpName.get());
    return;
  }
  PR_Delete(name.get());
  PR_Rename(tmpName.get(), name.get());
}
}

NS_IMETHODIMP
nsAppStartup::Quit(uint32_t aMode)
{
  uint32_t ferocity = (aMode & 0xF);

  // Quit the application. We will asynchronously call the appshell's
  // Exit() method via nsAppExitEvent to allow one last pass
  // through any events in the queue. This guarantees a tidy cleanup.
  nsresult rv = NS_OK;
  bool postedExitEvent = false;

  if (mShuttingDown)
    return NS_OK;

  RecordShutdownStartTimeStamp();

  // If we're considering quitting, we will only do so if:
  if (ferocity == eConsiderQuit) {
    if (mConsiderQuitStopper == 0) {
      // there are no windows...
      ferocity = eAttemptQuit;
    }
#ifdef XP_MACOSX
    else if (mConsiderQuitStopper == 1) {
      // ... or there is only a hiddenWindow left, and it's useless:
      nsCOMPtr<nsIAppShellService> appShell
        (do_GetService(NS_APPSHELLSERVICE_CONTRACTID));

      // Failure shouldn't be fatal, but will abort quit attempt:
      if (!appShell)
        return NS_OK;

      bool usefulHiddenWindow;
      appShell->GetApplicationProvidedHiddenWindow(&usefulHiddenWindow);
      nsCOMPtr<nsIXULWindow> hiddenWindow;
      appShell->GetHiddenWindow(getter_AddRefs(hiddenWindow));
      // If the one window is useful, we won't quit:
      if (!hiddenWindow || usefulHiddenWindow)
        return NS_OK;

      ferocity = eAttemptQuit;
    }
#endif
  }

  nsCOMPtr<nsIObserverService> obsService;
  if (ferocity == eAttemptQuit || ferocity == eForceQuit) {

    nsCOMPtr<nsISimpleEnumerator> windowEnumerator;
    nsCOMPtr<nsIWindowMediator> mediator (do_GetService(NS_WINDOWMEDIATOR_CONTRACTID));
    if (mediator) {
      mediator->GetEnumerator(nullptr, getter_AddRefs(windowEnumerator));
      if (windowEnumerator) {
        bool more;
        while (windowEnumerator->HasMoreElements(&more), more) {
          nsCOMPtr<nsISupports> window;
          windowEnumerator->GetNext(getter_AddRefs(window));
          nsCOMPtr<nsPIDOMWindow> domWindow(do_QueryInterface(window));
          if (domWindow) {
            if (!domWindow->CanClose())
              return NS_OK;
          }
        }
      }
    }

    mShuttingDown = true;
    if (!mRestart) {
      mRestart = (aMode & eRestart) != 0;
      gRestartMode = (aMode & 0xF0);
    }

    if (mRestart) {
      // Firefox-restarts reuse the process. Process start-time isn't a useful indicator of startup time
      PR_SetEnv(PR_smprintf("MOZ_APP_RESTART=%lld", (int64_t) PR_Now() / PR_USEC_PER_MSEC));
    }

    obsService = mozilla::services::GetObserverService();

    if (!mAttemptingQuit) {
      mAttemptingQuit = true;
#ifdef XP_MACOSX
      // now even the Mac wants to quit when the last window is closed
      ExitLastWindowClosingSurvivalArea();
#endif
      if (obsService)
        obsService->NotifyObservers(nullptr, "quit-application-granted", nullptr);
    }

    /* Enumerate through each open window and close it. It's important to do
       this before we forcequit because this can control whether we really quit
       at all. e.g. if one of these windows has an unload handler that
       opens a new window. Ugh. I know. */
    CloseAllWindows();

    if (mediator) {
      if (ferocity == eAttemptQuit) {
        ferocity = eForceQuit; // assume success

        /* Were we able to immediately close all windows? if not, eAttemptQuit
           failed. This could happen for a variety of reasons; in fact it's
           very likely. Perhaps we're being called from JS and the window->Close
           method hasn't had a chance to wrap itself up yet. So give up.
           We'll return (with eConsiderQuit) as the remaining windows are
           closed. */
        mediator->GetEnumerator(nullptr, getter_AddRefs(windowEnumerator));
        if (windowEnumerator) {
          bool more;
          while (windowEnumerator->HasMoreElements(&more), more) {
            /* we can't quit immediately. we'll try again as the last window
               finally closes. */
            ferocity = eAttemptQuit;
            nsCOMPtr<nsISupports> window;
            windowEnumerator->GetNext(getter_AddRefs(window));
            nsCOMPtr<nsIDOMWindow> domWindow = do_QueryInterface(window);
            if (domWindow) {
              bool closed = false;
              domWindow->GetClosed(&closed);
              if (!closed) {
                rv = NS_ERROR_FAILURE;
                break;
              }
            }
          }
        }
      }
    }
  }

  if (ferocity == eForceQuit) {
    // do it!

    // No chance of the shutdown being cancelled from here on; tell people
    // we're shutting down for sure while all services are still available.
    if (obsService) {
      NS_NAMED_LITERAL_STRING(shutdownStr, "shutdown");
      NS_NAMED_LITERAL_STRING(restartStr, "restart");
      obsService->NotifyObservers(nullptr, "quit-application",
        mRestart ? restartStr.get() : shutdownStr.get());
    }

    if (!mRunning) {
      postedExitEvent = true;
    }
    else {
      // no matter what, make sure we send the exit event.  If
      // worst comes to worst, we'll do a leaky shutdown but we WILL
      // shut down. Well, assuming that all *this* stuff works ;-).
      nsCOMPtr<nsIRunnable> event = new nsAppExitEvent(this);
      rv = NS_DispatchToCurrentThread(event);
      if (NS_SUCCEEDED(rv)) {
        postedExitEvent = true;
      }
      else {
        NS_WARNING("failed to dispatch nsAppExitEvent");
      }
    }
  }

  // turn off the reentrancy check flag, but not if we have
  // more asynchronous work to do still.
  if (!postedExitEvent)
    mShuttingDown = false;
  return rv;
}


void
nsAppStartup::CloseAllWindows()
{
  nsCOMPtr<nsIWindowMediator> mediator
    (do_GetService(NS_WINDOWMEDIATOR_CONTRACTID));

  nsCOMPtr<nsISimpleEnumerator> windowEnumerator;

  mediator->GetEnumerator(nullptr, getter_AddRefs(windowEnumerator));

  if (!windowEnumerator)
    return;

  bool more;
  while (NS_SUCCEEDED(windowEnumerator->HasMoreElements(&more)) && more) {
    nsCOMPtr<nsISupports> isupports;
    if (NS_FAILED(windowEnumerator->GetNext(getter_AddRefs(isupports))))
      break;

    nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(isupports);
    NS_ASSERTION(window, "not an nsPIDOMWindow");
    if (window)
      window->ForceClose();
  }
}

NS_IMETHODIMP
nsAppStartup::EnterLastWindowClosingSurvivalArea(void)
{
  ++mConsiderQuitStopper;
  return NS_OK;
}


NS_IMETHODIMP
nsAppStartup::ExitLastWindowClosingSurvivalArea(void)
{
  NS_ASSERTION(mConsiderQuitStopper > 0, "consider quit stopper out of bounds");
  --mConsiderQuitStopper;

  if (mRunning)
    Quit(eConsiderQuit);

  return NS_OK;
}

NS_IMETHODIMP
nsAppStartup::GetLastShutdownDuration(uint32_t *aResult)
{
  // We make this check so that GetShutdownTimeFileName() doesn't get
  // called; calling that function without telemetry enabled violates
  // assumptions that the write-the-shutdown-timestamp machinery makes.
  if (!Telemetry::CanRecord()) {
    *aResult = 0;
    return NS_OK;
  }

  if (!mCachedShutdownTime) {
    const char *filename = GetShutdownTimeFileName();

    if (!filename) {
      *aResult = 0;
      return NS_OK;
    }

    FILE *f = fopen(filename, "r");
    if (!f) {
      *aResult = 0;
      return NS_OK;
    }

    int shutdownTime;
    int r = fscanf(f, "%d\n", &shutdownTime);
    fclose(f);
    if (r != 1) {
      *aResult = 0;
      return NS_OK;
    }

    mLastShutdownTime = shutdownTime;
    mCachedShutdownTime = true;
  }

  *aResult = mLastShutdownTime;
  return NS_OK;
}

//
// nsAppStartup->nsIAppStartup2
//

NS_IMETHODIMP
nsAppStartup::GetShuttingDown(bool *aResult)
{
  *aResult = mShuttingDown;
  return NS_OK;
}

NS_IMETHODIMP
nsAppStartup::SetInterrupted(bool aInterrupted)
{
  mInterrupted = aInterrupted;
  return NS_OK;
}

NS_IMETHODIMP
nsAppStartup::GetInterrupted(bool *aInterrupted)
{
  *aInterrupted = mInterrupted;
  return NS_OK;
}

//
// nsAppStartup->nsIWindowCreator
//

NS_IMETHODIMP
nsAppStartup::CreateChromeWindow(nsIWebBrowserChrome *aParent,
                                 uint32_t aChromeFlags,
                                 nsIWebBrowserChrome **_retval)
{
  bool cancel;
  return CreateChromeWindow2(aParent, aChromeFlags, 0, 0, &cancel, _retval);
}


//
// nsAppStartup->nsIWindowCreator2
//

NS_IMETHODIMP
nsAppStartup::CreateChromeWindow2(nsIWebBrowserChrome *aParent,
                                  uint32_t aChromeFlags,
                                  uint32_t aContextFlags,
                                  nsIURI *aURI,
                                  bool *aCancel,
                                  nsIWebBrowserChrome **_retval)
{
  NS_ENSURE_ARG_POINTER(aCancel);
  NS_ENSURE_ARG_POINTER(_retval);
  *aCancel = false;
  *_retval = 0;

  // Non-modal windows cannot be opened if we are attempting to quit
  if (mAttemptingQuit && (aChromeFlags & nsIWebBrowserChrome::CHROME_MODAL) == 0)
    return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;

  nsCOMPtr<nsIXULWindow> newWindow;

  if (aParent) {
    nsCOMPtr<nsIXULWindow> xulParent(do_GetInterface(aParent));
    NS_ASSERTION(xulParent, "window created using non-XUL parent. that's unexpected, but may work.");

    if (xulParent)
      xulParent->CreateNewWindow(aChromeFlags, getter_AddRefs(newWindow));
    // And if it fails, don't try again without a parent. It could fail
    // intentionally (bug 115969).
  } else { // try using basic methods:
    /* You really shouldn't be making dependent windows without a parent.
      But unparented modal (and therefore dependent) windows happen
      in our codebase, so we allow it after some bellyaching: */
    if (aChromeFlags & nsIWebBrowserChrome::CHROME_DEPENDENT)
      NS_WARNING("dependent window created without a parent");

    nsCOMPtr<nsIAppShellService> appShell(do_GetService(NS_APPSHELLSERVICE_CONTRACTID));
    if (!appShell)
      return NS_ERROR_FAILURE;
    
    appShell->CreateTopLevelWindow(0, 0, aChromeFlags,
                                   nsIAppShellService::SIZE_TO_CONTENT,
                                   nsIAppShellService::SIZE_TO_CONTENT,
                                   getter_AddRefs(newWindow));
  }

  // if anybody gave us anything to work with, use it
  if (newWindow) {
    newWindow->SetContextFlags(aContextFlags);
    nsCOMPtr<nsIInterfaceRequestor> thing(do_QueryInterface(newWindow));
    if (thing)
      CallGetInterface(thing.get(), _retval);
  }

  return *_retval ? NS_OK : NS_ERROR_FAILURE;
}


//
// nsAppStartup->nsIObserver
//

NS_IMETHODIMP
nsAppStartup::Observe(nsISupports *aSubject,
                      const char *aTopic, const PRUnichar *aData)
{
  NS_ASSERTION(mAppShell, "appshell service notified before appshell built");
  if (!strcmp(aTopic, "quit-application-forced")) {
    mShuttingDown = true;
  }
  else if (!strcmp(aTopic, "profile-change-teardown")) {
    if (!mShuttingDown) {
      EnterLastWindowClosingSurvivalArea();
      CloseAllWindows();
      ExitLastWindowClosingSurvivalArea();
    }
  } else if (!strcmp(aTopic, "xul-window-registered")) {
    EnterLastWindowClosingSurvivalArea();
  } else if (!strcmp(aTopic, "xul-window-destroyed")) {
    ExitLastWindowClosingSurvivalArea();
  } else if (!strcmp(aTopic, "sessionstore-windows-restored")) {
    StartupTimeline::Record(StartupTimeline::SESSION_RESTORED);
#if defined(XP_WIN)
    if (mSessionWindowRestoredProbe) {
      mSessionWindowRestoredProbe->Trigger();
    }
  } else if (!strcmp(aTopic, "places-init-complete")) {
    if (mPlacesInitCompleteProbe) {
      mPlacesInitCompleteProbe->Trigger();
    }
  } else if (!strcmp(aTopic, "xpcom-shutdown")) {
    if (mXPCOMShutdownProbe) {
      mXPCOMShutdownProbe->Trigger();
    }
#endif //defined(XP_WIN)
  } else {
    NS_ERROR("Unexpected observer topic.");
  }

  return NS_OK;
}

#if defined(LINUX) || defined(ANDROID)
static uint64_t 
JiffiesSinceBoot(const char *file)
{
  char stat[512];
  FILE *f = fopen(file, "r");
  if (!f)
    return 0;
  int n = fread(&stat, 1, sizeof(stat) - 1, f);
  fclose(f);
  if (n <= 0)
    return 0;
  stat[n] = 0;
  
  long long unsigned starttime = 0; // instead of uint64_t to keep GCC quiet
  
  char *s = strrchr(stat, ')');
  if (!s)
    return 0;
  int ret = sscanf(s + 2,
                   "%*c %*d %*d %*d %*d %*d %*u %*u %*u %*u "
                   "%*u %*u %*u %*u %*u %*d %*d %*d %*d %llu",
                   &starttime);
  if (ret != 1 || !starttime)
    return 0;
  return starttime;
}

static void
ThreadedCalculateProcessCreationTimestamp(void *aClosure)
{
  PR_SetCurrentThreadName("Startup Timer");

  PRTime now = PR_Now();
  long hz = sysconf(_SC_CLK_TCK);
  if (!hz)
    return;

  char thread_stat[40];
  sprintf(thread_stat, "/proc/self/task/%d/stat", (pid_t) syscall(__NR_gettid));
  
  uint64_t thread_jiffies = JiffiesSinceBoot(thread_stat);
  uint64_t self_jiffies = JiffiesSinceBoot("/proc/self/stat");
  
  if (!thread_jiffies || !self_jiffies)
    return;

  PRTime interval = (thread_jiffies - self_jiffies) * PR_USEC_PER_SEC / hz;
  StartupTimeline::Record(StartupTimeline::PROCESS_CREATION, now - interval);
}

static PRTime
CalculateProcessCreationTimestamp()
{
 PRThread *thread = PR_CreateThread(PR_USER_THREAD,
                                    ThreadedCalculateProcessCreationTimestamp,
                                    NULL,
                                    PR_PRIORITY_NORMAL,
                                    PR_LOCAL_THREAD,
                                    PR_JOINABLE_THREAD,
                                    0);

  PR_JoinThread(thread);
  return StartupTimeline::Get(StartupTimeline::PROCESS_CREATION);
}
#elif defined(XP_WIN)
static PRTime
CalculateProcessCreationTimestamp()
{
  FILETIME start, foo, bar, baz;
  bool success = GetProcessTimes(GetCurrentProcess(), &start, &foo, &bar, &baz);
  if (!success)
    return 0;
  // copied from NSPR _PR_FileTimeToPRTime
  uint64_t timestamp = 0;
  CopyMemory(&timestamp, &start, sizeof(PRTime));
#ifdef __GNUC__
  timestamp = (timestamp - 116444736000000000LL) / 10LL;
#else
  timestamp = (timestamp - 116444736000000000i64) / 10i64;
#endif
  return timestamp;
}
#elif defined(XP_MACOSX) || defined(__DragonFly__) || defined(__FreeBSD__) \
  || defined(__NetBSD__) || defined(__OpenBSD__)
static PRTime
CalculateProcessCreationTimestamp()
{
  int mib[] = {
    CTL_KERN,
    KERN_PROC,
    KERN_PROC_PID,
    getpid(),
#if defined(__NetBSD__) || defined(__OpenBSD__)
    sizeof(KINFO_PROC),
    1,
#endif
  };
  u_int miblen = sizeof(mib) / sizeof(mib[0]);

  KINFO_PROC proc;
  size_t buffer_size = sizeof(proc);
  if (sysctl(mib, miblen, &proc, &buffer_size, NULL, 0))
    return 0;

  PRTime starttime = static_cast<PRTime>(proc.KP_START_SEC) * PR_USEC_PER_SEC;
  starttime += proc.KP_START_USEC;
  return starttime;
}
#else
static PRTime
CalculateProcessCreationTimestamp()
{
  return 0;
}
#endif
 
NS_IMETHODIMP
nsAppStartup::GetStartupInfo(JSContext* aCx, JS::Value* aRetval)
{
  JSObject *obj = JS_NewObject(aCx, NULL, NULL, NULL);
  *aRetval = OBJECT_TO_JSVAL(obj);

  PRTime ProcessCreationTimestamp = StartupTimeline::Get(StartupTimeline::PROCESS_CREATION);

  if (!ProcessCreationTimestamp) {
    char *moz_app_restart = PR_GetEnv("MOZ_APP_RESTART");
    if (moz_app_restart) {
      ProcessCreationTimestamp = nsCRT::atoll(moz_app_restart) * PR_USEC_PER_MSEC;
    } else {
      ProcessCreationTimestamp = CalculateProcessCreationTimestamp();
    }
    // Bug 670008: Avoid obviously invalid process creation times
    if (PR_Now() <= ProcessCreationTimestamp) {
      ProcessCreationTimestamp = -1;
      Telemetry::Accumulate(Telemetry::STARTUP_MEASUREMENT_ERRORS, StartupTimeline::PROCESS_CREATION);
    }
    StartupTimeline::Record(StartupTimeline::PROCESS_CREATION, ProcessCreationTimestamp);
  }

  for (int i = StartupTimeline::PROCESS_CREATION; i < StartupTimeline::MAX_EVENT_ID; ++i) {
    StartupTimeline::Event ev = static_cast<StartupTimeline::Event>(i);
    if (StartupTimeline::Get(ev) > 0) {
      // always define main to aid with bug 689256
      if ((ev != StartupTimeline::MAIN) &&
          (StartupTimeline::Get(ev) < StartupTimeline::Get(StartupTimeline::PROCESS_CREATION))) {
        Telemetry::Accumulate(Telemetry::STARTUP_MEASUREMENT_ERRORS, i);
        StartupTimeline::Record(ev, -1);
      } else {
        JSObject *date = JS_NewDateObjectMsec(aCx, StartupTimeline::Get(ev) / PR_USEC_PER_MSEC);
        JS_DefineProperty(aCx, obj, StartupTimeline::Describe(ev), OBJECT_TO_JSVAL(date), NULL, NULL, JSPROP_ENUMERATE);
      }
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsAppStartup::GetAutomaticSafeModeNecessary(bool *_retval)
{
  NS_ENSURE_ARG_POINTER(_retval);

  *_retval = mIsSafeModeNecessary;
  return NS_OK;
}

NS_IMETHODIMP
nsAppStartup::TrackStartupCrashBegin(bool *aIsSafeModeNecessary)
{
  const int32_t MAX_TIME_SINCE_STARTUP = 6 * 60 * 60 * 1000;
  const int32_t MAX_STARTUP_BUFFER = 10;
  nsresult rv;

  mStartupCrashTrackingEnded = false;

  StartupTimeline::Record(StartupTimeline::STARTUP_CRASH_DETECTION_BEGIN);

  bool hasLastSuccess = Preferences::HasUserValue(kPrefLastSuccess);
  if (!hasLastSuccess) {
    // Clear so we don't get stuck with SafeModeNecessary returning true if we
    // have had too many recent crashes and the last success pref is missing.
    Preferences::ClearUser(kPrefRecentCrashes);
    return NS_ERROR_NOT_AVAILABLE;
  }

  bool inSafeMode = false;
  nsCOMPtr<nsIXULRuntime> xr = do_GetService(XULRUNTIME_SERVICE_CONTRACTID);
  NS_ENSURE_TRUE(xr, NS_ERROR_FAILURE);

  xr->GetInSafeMode(&inSafeMode);

  PRTime replacedLockTime;
  rv = xr->GetReplacedLockTime(&replacedLockTime);

  if (NS_FAILED(rv) || !replacedLockTime) {
    if (!inSafeMode)
      Preferences::ClearUser(kPrefRecentCrashes);
    GetAutomaticSafeModeNecessary(aIsSafeModeNecessary);
    return NS_OK;
  }

  // check whether safe mode is necessary
  int32_t maxResumedCrashes = -1;
  rv = Preferences::GetInt(kPrefMaxResumedCrashes, &maxResumedCrashes);
  NS_ENSURE_SUCCESS(rv, NS_OK);

  int32_t recentCrashes = 0;
  Preferences::GetInt(kPrefRecentCrashes, &recentCrashes);
  mIsSafeModeNecessary = (recentCrashes > maxResumedCrashes && maxResumedCrashes != -1);

  // Bug 731613 - Don't check if the last startup was a crash if XRE_PROFILE_PATH is set.  After
  // profile manager, the profile lock's mod. time has been changed so can't be used on this startup.
  // After a restart, it's safe to assume the last startup was successful.
  char *xreProfilePath = PR_GetEnv("XRE_PROFILE_PATH");
  if (xreProfilePath) {
    GetAutomaticSafeModeNecessary(aIsSafeModeNecessary);
    return NS_ERROR_NOT_AVAILABLE;
  }

  // time of last successful startup
  int32_t lastSuccessfulStartup;
  rv = Preferences::GetInt(kPrefLastSuccess, &lastSuccessfulStartup);
  NS_ENSURE_SUCCESS(rv, rv);

  int32_t lockSeconds = (int32_t)(replacedLockTime / PR_MSEC_PER_SEC);

  // started close enough to good startup so call it good
  if (lockSeconds <= lastSuccessfulStartup + MAX_STARTUP_BUFFER
      && lockSeconds >= lastSuccessfulStartup - MAX_STARTUP_BUFFER) {
    GetAutomaticSafeModeNecessary(aIsSafeModeNecessary);
    return NS_OK;
  }

  // sanity check that the pref set at last success is not greater than the current time
  if (PR_Now() / PR_USEC_PER_SEC <= lastSuccessfulStartup)
    return NS_ERROR_FAILURE;

  // The last startup was a crash so include it in the count regardless of when it happened.
  Telemetry::Accumulate(Telemetry::STARTUP_CRASH_DETECTED, true);

  if (inSafeMode) {
    GetAutomaticSafeModeNecessary(aIsSafeModeNecessary);
    return NS_OK;
  }

  PRTime now = (PR_Now() / PR_USEC_PER_MSEC);
  // if the last startup attempt which crashed was in the last 6 hours
  if (replacedLockTime >= now - MAX_TIME_SINCE_STARTUP) {
    NS_WARNING("Last startup was detected as a crash.");
    recentCrashes++;
    rv = Preferences::SetInt(kPrefRecentCrashes, recentCrashes);
  } else {
    // Otherwise ignore that crash and all previous since it may not be applicable anymore
    // and we don't want someone to get stuck in safe mode if their prefs are read-only.
    rv = Preferences::ClearUser(kPrefRecentCrashes);
  }
  NS_ENSURE_SUCCESS(rv, rv);

  // recalculate since recent crashes count may have changed above
  mIsSafeModeNecessary = (recentCrashes > maxResumedCrashes && maxResumedCrashes != -1);

  nsCOMPtr<nsIPrefService> prefs = Preferences::GetService();
  rv = prefs->SavePrefFile(nullptr); // flush prefs to disk since we are tracking crashes
  NS_ENSURE_SUCCESS(rv, rv);

  GetAutomaticSafeModeNecessary(aIsSafeModeNecessary);
  return rv;
}

NS_IMETHODIMP
nsAppStartup::TrackStartupCrashEnd()
{
  bool inSafeMode = false;
  nsCOMPtr<nsIXULRuntime> xr = do_GetService(XULRUNTIME_SERVICE_CONTRACTID);
  if (xr)
    xr->GetInSafeMode(&inSafeMode);

  // return if we already ended or we're restarting into safe mode
  if (mStartupCrashTrackingEnded || (mIsSafeModeNecessary && !inSafeMode))
    return NS_OK;
  mStartupCrashTrackingEnded = true;

  StartupTimeline::Record(StartupTimeline::STARTUP_CRASH_DETECTION_END);

  // Use the timestamp of XRE_main as an approximation for the lock file timestamp.
  // See MAX_STARTUP_BUFFER for the buffer time period.
  nsresult rv;
  PRTime mainTime = StartupTimeline::Get(StartupTimeline::MAIN);
  if (mainTime <= 0) {
    NS_WARNING("Could not get StartupTimeline::MAIN time.");
  } else {
    int32_t lockFileTime = (int32_t)(mainTime / PR_USEC_PER_SEC);
    rv = Preferences::SetInt(kPrefLastSuccess, lockFileTime);
    if (NS_FAILED(rv)) NS_WARNING("Could not set startup crash detection pref.");
  }

  if (inSafeMode && mIsSafeModeNecessary) {
    // On a successful startup in automatic safe mode, allow the user one more crash
    // in regular mode before returning to safe mode.
    int32_t maxResumedCrashes = 0;
    int32_t prefType;
    rv = Preferences::GetDefaultRootBranch()->GetPrefType(kPrefMaxResumedCrashes, &prefType);
    NS_ENSURE_SUCCESS(rv, rv);
    if (prefType == nsIPrefBranch::PREF_INT) {
      rv = Preferences::GetInt(kPrefMaxResumedCrashes, &maxResumedCrashes);
      NS_ENSURE_SUCCESS(rv, rv);
    }
    rv = Preferences::SetInt(kPrefRecentCrashes, maxResumedCrashes);
    NS_ENSURE_SUCCESS(rv, rv);
  } else if (!inSafeMode) {
    // clear the count of recent crashes after a succesful startup when not in safe mode
    rv = Preferences::ClearUser(kPrefRecentCrashes);
    if (NS_FAILED(rv)) NS_WARNING("Could not clear startup crash count.");
  }
  nsCOMPtr<nsIPrefService> prefs = Preferences::GetService();
  rv = prefs->SavePrefFile(nullptr); // flush prefs to disk since we are tracking crashes

  return rv;
}

NS_IMETHODIMP
nsAppStartup::RestartInSafeMode(uint32_t aQuitMode)
{
  PR_SetEnv("MOZ_SAFE_MODE_RESTART=1");
  this->Quit(aQuitMode | nsIAppStartup::eRestart);

  return NS_OK;
}