gecko-dev/netwerk/cache/nsDeleteDir.cpp
Nathan Froyd 2f23818440 Bug 1339617 - move GetClosure call prior to canceling timer; r=mayhemer
Some recent work on timers changed how we handle callbacks and
associated closure data: prior to these changes, canceling timers would
not null out associated closure data, so calling GetClosure() on a timer
after canceling it would return what you had put in.  After these
changes, however, GetClosure() after cancellation would retrieve a null
value, causing anything that assumed non-nullness to crash.  The simple
fix is to move the GetClosure() call prior to Cancel()'ing the timer.
2017-02-21 13:35:52 -05:00

455 lines
11 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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 "nsDeleteDir.h"
#include "nsIFile.h"
#include "nsString.h"
#include "mozilla/Telemetry.h"
#include "nsITimer.h"
#include "nsISimpleEnumerator.h"
#include "nsAutoPtr.h"
#include "nsThreadUtils.h"
#include "nsISupportsPriority.h"
#include "nsCacheUtils.h"
#include "prtime.h"
#include <time.h>
using namespace mozilla;
class nsBlockOnBackgroundThreadEvent : public Runnable {
public:
nsBlockOnBackgroundThreadEvent() {}
NS_IMETHOD Run() override
{
MutexAutoLock lock(nsDeleteDir::gInstance->mLock);
nsDeleteDir::gInstance->mNotified = true;
nsDeleteDir::gInstance->mCondVar.Notify();
return NS_OK;
}
};
nsDeleteDir * nsDeleteDir::gInstance = nullptr;
nsDeleteDir::nsDeleteDir()
: mLock("nsDeleteDir.mLock"),
mCondVar(mLock, "nsDeleteDir.mCondVar"),
mNotified(false),
mShutdownPending(false),
mStopDeleting(false)
{
NS_ASSERTION(gInstance==nullptr, "multiple nsCacheService instances!");
}
nsDeleteDir::~nsDeleteDir()
{
gInstance = nullptr;
}
nsresult
nsDeleteDir::Init()
{
if (gInstance)
return NS_ERROR_ALREADY_INITIALIZED;
gInstance = new nsDeleteDir();
return NS_OK;
}
nsresult
nsDeleteDir::Shutdown(bool finishDeleting)
{
if (!gInstance)
return NS_ERROR_NOT_INITIALIZED;
nsCOMArray<nsIFile> dirsToRemove;
nsCOMPtr<nsIThread> thread;
{
MutexAutoLock lock(gInstance->mLock);
NS_ASSERTION(!gInstance->mShutdownPending,
"Unexpected state in nsDeleteDir::Shutdown()");
gInstance->mShutdownPending = true;
if (!finishDeleting)
gInstance->mStopDeleting = true;
// remove all pending timers
for (int32_t i = gInstance->mTimers.Count(); i > 0; i--) {
nsCOMPtr<nsITimer> timer = gInstance->mTimers[i-1];
gInstance->mTimers.RemoveObjectAt(i-1);
nsCOMArray<nsIFile> *arg;
timer->GetClosure((reinterpret_cast<void**>(&arg)));
timer->Cancel();
if (finishDeleting)
dirsToRemove.AppendObjects(*arg);
// delete argument passed to the timer
delete arg;
}
thread.swap(gInstance->mThread);
if (thread) {
// dispatch event and wait for it to run and notify us, so we know thread
// has completed all work and can be shutdown
nsCOMPtr<nsIRunnable> event = new nsBlockOnBackgroundThreadEvent();
nsresult rv = thread->Dispatch(event, NS_DISPATCH_NORMAL);
if (NS_FAILED(rv)) {
NS_WARNING("Failed dispatching block-event");
return NS_ERROR_UNEXPECTED;
}
gInstance->mNotified = false;
while (!gInstance->mNotified) {
gInstance->mCondVar.Wait();
}
nsShutdownThread::BlockingShutdown(thread);
}
}
delete gInstance;
for (int32_t i = 0; i < dirsToRemove.Count(); i++)
dirsToRemove[i]->Remove(true);
return NS_OK;
}
nsresult
nsDeleteDir::InitThread()
{
if (mThread)
return NS_OK;
nsresult rv = NS_NewNamedThread("Cache Deleter", getter_AddRefs(mThread));
if (NS_FAILED(rv)) {
NS_WARNING("Can't create background thread");
return rv;
}
nsCOMPtr<nsISupportsPriority> p = do_QueryInterface(mThread);
if (p) {
p->SetPriority(nsISupportsPriority::PRIORITY_LOWEST);
}
return NS_OK;
}
void
nsDeleteDir::DestroyThread()
{
if (!mThread)
return;
if (mTimers.Count())
// more work to do, so don't delete thread.
return;
nsShutdownThread::Shutdown(mThread);
mThread = nullptr;
}
void
nsDeleteDir::TimerCallback(nsITimer *aTimer, void *arg)
{
Telemetry::AutoTimer<Telemetry::NETWORK_DISK_CACHE_DELETEDIR> timer;
{
MutexAutoLock lock(gInstance->mLock);
int32_t idx = gInstance->mTimers.IndexOf(aTimer);
if (idx == -1) {
// Timer was canceled and removed during shutdown.
return;
}
gInstance->mTimers.RemoveObjectAt(idx);
}
nsAutoPtr<nsCOMArray<nsIFile> > dirList;
dirList = static_cast<nsCOMArray<nsIFile> *>(arg);
bool shuttingDown = false;
// Intentional extra braces to control variable sope.
{
// Low IO priority can only be set when running in the context of the
// current thread. So this shouldn't be moved to where we set the priority
// of the Cache deleter thread using the nsThread's NSPR priority constants.
nsAutoLowPriorityIO autoLowPriority;
for (int32_t i = 0; i < dirList->Count() && !shuttingDown; i++) {
gInstance->RemoveDir((*dirList)[i], &shuttingDown);
}
}
{
MutexAutoLock lock(gInstance->mLock);
gInstance->DestroyThread();
}
}
nsresult
nsDeleteDir::DeleteDir(nsIFile *dirIn, bool moveToTrash, uint32_t delay)
{
Telemetry::AutoTimer<Telemetry::NETWORK_DISK_CACHE_TRASHRENAME> timer;
if (!gInstance)
return NS_ERROR_NOT_INITIALIZED;
nsresult rv;
nsCOMPtr<nsIFile> trash, dir;
// Need to make a clone of this since we don't want to modify the input
// file object.
rv = dirIn->Clone(getter_AddRefs(dir));
if (NS_FAILED(rv))
return rv;
if (moveToTrash) {
rv = GetTrashDir(dir, &trash);
if (NS_FAILED(rv))
return rv;
nsAutoCString origLeaf;
rv = trash->GetNativeLeafName(origLeaf);
if (NS_FAILED(rv))
return rv;
// Append random number to the trash directory and check if it exists.
srand(static_cast<unsigned>(PR_Now()));
nsAutoCString leaf;
for (int32_t i = 0; i < 10; i++) {
leaf = origLeaf;
leaf.AppendInt(rand());
rv = trash->SetNativeLeafName(leaf);
if (NS_FAILED(rv))
return rv;
bool exists;
if (NS_SUCCEEDED(trash->Exists(&exists)) && !exists) {
break;
}
leaf.Truncate();
}
// Fail if we didn't find unused trash directory within the limit
if (!leaf.Length())
return NS_ERROR_FAILURE;
#if defined(MOZ_WIDGET_ANDROID)
nsCOMPtr<nsIFile> parent;
rv = trash->GetParent(getter_AddRefs(parent));
if (NS_FAILED(rv))
return rv;
rv = dir->MoveToNative(parent, leaf);
#else
// Important: must rename directory w/o changing parent directory: else on
// NTFS we'll wait (with cache lock) while nsIFile's ACL reset walks file
// tree: was hanging GUI for *minutes* on large cache dirs.
rv = dir->MoveToNative(nullptr, leaf);
#endif
if (NS_FAILED(rv))
return rv;
} else {
// we want to pass a clone of the original off to the worker thread.
trash.swap(dir);
}
nsAutoPtr<nsCOMArray<nsIFile> > arg(new nsCOMArray<nsIFile>);
arg->AppendObject(trash);
rv = gInstance->PostTimer(arg, delay);
if (NS_FAILED(rv))
return rv;
arg.forget();
return NS_OK;
}
nsresult
nsDeleteDir::GetTrashDir(nsIFile *target, nsCOMPtr<nsIFile> *result)
{
nsresult rv;
#if defined(MOZ_WIDGET_ANDROID)
// Try to use the app cache folder for cache trash on Android
char* cachePath = getenv("CACHE_DIRECTORY");
if (cachePath) {
rv = NS_NewNativeLocalFile(nsDependentCString(cachePath),
true, getter_AddRefs(*result));
if (NS_FAILED(rv))
return rv;
// Add a sub folder with the cache folder name
nsAutoCString leaf;
rv = target->GetNativeLeafName(leaf);
(*result)->AppendNative(leaf);
} else
#endif
{
rv = target->Clone(getter_AddRefs(*result));
}
if (NS_FAILED(rv))
return rv;
nsAutoCString leaf;
rv = (*result)->GetNativeLeafName(leaf);
if (NS_FAILED(rv))
return rv;
leaf.AppendLiteral(".Trash");
return (*result)->SetNativeLeafName(leaf);
}
nsresult
nsDeleteDir::RemoveOldTrashes(nsIFile *cacheDir)
{
if (!gInstance)
return NS_ERROR_NOT_INITIALIZED;
nsresult rv;
nsCOMPtr<nsIFile> trash;
rv = GetTrashDir(cacheDir, &trash);
if (NS_FAILED(rv))
return rv;
nsAutoString trashName;
rv = trash->GetLeafName(trashName);
if (NS_FAILED(rv))
return rv;
nsCOMPtr<nsIFile> parent;
#if defined(MOZ_WIDGET_ANDROID)
rv = trash->GetParent(getter_AddRefs(parent));
#else
rv = cacheDir->GetParent(getter_AddRefs(parent));
#endif
if (NS_FAILED(rv))
return rv;
nsCOMPtr<nsISimpleEnumerator> iter;
rv = parent->GetDirectoryEntries(getter_AddRefs(iter));
if (NS_FAILED(rv))
return rv;
bool more;
nsCOMPtr<nsISupports> elem;
nsAutoPtr<nsCOMArray<nsIFile> > dirList;
while (NS_SUCCEEDED(iter->HasMoreElements(&more)) && more) {
rv = iter->GetNext(getter_AddRefs(elem));
if (NS_FAILED(rv))
continue;
nsCOMPtr<nsIFile> file = do_QueryInterface(elem);
if (!file)
continue;
nsAutoString leafName;
rv = file->GetLeafName(leafName);
if (NS_FAILED(rv))
continue;
// match all names that begin with the trash name (i.e. "Cache.Trash")
if (Substring(leafName, 0, trashName.Length()).Equals(trashName)) {
if (!dirList)
dirList = new nsCOMArray<nsIFile>;
dirList->AppendObject(file);
}
}
if (dirList) {
rv = gInstance->PostTimer(dirList, 90000);
if (NS_FAILED(rv))
return rv;
dirList.forget();
}
return NS_OK;
}
nsresult
nsDeleteDir::PostTimer(void *arg, uint32_t delay)
{
nsresult rv;
nsCOMPtr<nsITimer> timer = do_CreateInstance("@mozilla.org/timer;1", &rv);
if (NS_FAILED(rv))
return NS_ERROR_UNEXPECTED;
MutexAutoLock lock(mLock);
rv = InitThread();
if (NS_FAILED(rv))
return rv;
rv = timer->SetTarget(mThread);
if (NS_FAILED(rv))
return rv;
rv = timer->InitWithFuncCallback(TimerCallback, arg, delay,
nsITimer::TYPE_ONE_SHOT);
if (NS_FAILED(rv))
return rv;
mTimers.AppendObject(timer);
return NS_OK;
}
nsresult
nsDeleteDir::RemoveDir(nsIFile *file, bool *stopDeleting)
{
nsresult rv;
bool isLink;
rv = file->IsSymlink(&isLink);
if (NS_FAILED(rv) || isLink)
return NS_ERROR_UNEXPECTED;
bool isDir;
rv = file->IsDirectory(&isDir);
if (NS_FAILED(rv))
return rv;
if (isDir) {
nsCOMPtr<nsISimpleEnumerator> iter;
rv = file->GetDirectoryEntries(getter_AddRefs(iter));
if (NS_FAILED(rv))
return rv;
bool more;
nsCOMPtr<nsISupports> elem;
while (NS_SUCCEEDED(iter->HasMoreElements(&more)) && more) {
rv = iter->GetNext(getter_AddRefs(elem));
if (NS_FAILED(rv)) {
NS_WARNING("Unexpected failure in nsDeleteDir::RemoveDir");
continue;
}
nsCOMPtr<nsIFile> file2 = do_QueryInterface(elem);
if (!file2) {
NS_WARNING("Unexpected failure in nsDeleteDir::RemoveDir");
continue;
}
RemoveDir(file2, stopDeleting);
// No check for errors to remove as much as possible
if (*stopDeleting)
return NS_OK;
}
}
file->Remove(false);
// No check for errors to remove as much as possible
MutexAutoLock lock(mLock);
if (mStopDeleting)
*stopDeleting = true;
return NS_OK;
}