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/*
* Copyright (C) by Daniel Molkentin <danimo@owncloud.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include <QThread>
#include <QDir>
#include "filesystem.h"
#include "folderwatcher.h"
#include "folderwatcher_win.h"
#include "common/utility.h"
#include <stdlib.h>
#include <stdio.h>
#include <tchar.h>
namespace OCC {
void WatcherThread::watchChanges(size_t fileNotifyBufferSize,
bool *increaseBufferSize)
{
*increaseBufferSize = false;
QString longPath = FileSystem::longWinPath(_path);
_directory = CreateFileW(
(wchar_t *)longPath.utf16(),
FILE_LIST_DIRECTORY,
FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE,
nullptr,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
nullptr);
if (_directory == INVALID_HANDLE_VALUE) {
DWORD errorCode = GetLastError();
qCWarning(lcFolderWatcher) << "Failed to create handle for" << _path << ", error:" << errorCode;
_directory = 0;
return;
}
OVERLAPPED overlapped;
overlapped.hEvent = _resultEvent;
// QVarLengthArray ensures the stack-buffer is aligned like double and qint64.
QVarLengthArray<char, 4096 * 10> fileNotifyBuffer;
fileNotifyBuffer.resize(OCC::Utility::convertSizeToInt(fileNotifyBufferSize));
const size_t fileNameBufferSize = 4096;
TCHAR fileNameBuffer[fileNameBufferSize];
while (!_done) {
ResetEvent(_resultEvent);
FILE_NOTIFY_INFORMATION *pFileNotifyBuffer =
(FILE_NOTIFY_INFORMATION *)fileNotifyBuffer.data();
DWORD dwBytesReturned = 0;
SecureZeroMemory(pFileNotifyBuffer, fileNotifyBufferSize);
if (!ReadDirectoryChangesW(_directory, (LPVOID)pFileNotifyBuffer,
OCC::Utility::convertSizeToDWORD(fileNotifyBufferSize), true,
FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME | FILE_NOTIFY_CHANGE_LAST_WRITE,
&dwBytesReturned,
&overlapped,
nullptr)) {
DWORD errorCode = GetLastError();
if (errorCode == ERROR_NOTIFY_ENUM_DIR) {
qCDebug(lcFolderWatcher) << "The buffer for changes overflowed! Triggering a generic change and resizing";
emit changed(_path);
*increaseBufferSize = true;
} else {
qCWarning(lcFolderWatcher) << "ReadDirectoryChangesW error" << errorCode;
}
break;
}
HANDLE handles[] = { _resultEvent, _stopEvent };
DWORD result = WaitForMultipleObjects(
2, handles,
false, // awake once one of them arrives
INFINITE);
if (result == 1) {
qCDebug(lcFolderWatcher) << "Received stop event, aborting folder watcher thread";
break;
}
if (result != 0) {
qCWarning(lcFolderWatcher) << "WaitForMultipleObjects failed" << result << GetLastError();
break;
}
bool ok = GetOverlappedResult(_directory, &overlapped, &dwBytesReturned, false);
if (!ok) {
DWORD errorCode = GetLastError();
if (errorCode == ERROR_NOTIFY_ENUM_DIR) {
qCDebug(lcFolderWatcher) << "The buffer for changes overflowed! Triggering a generic change and resizing";
emit lostChanges();
emit changed(_path);
*increaseBufferSize = true;
} else {
qCWarning(lcFolderWatcher) << "GetOverlappedResult error" << errorCode;
}
break;
}
FILE_NOTIFY_INFORMATION *curEntry = pFileNotifyBuffer;
forever {
size_t len = curEntry->FileNameLength / 2;
QString file = _path + "\\" + QString::fromWCharArray(curEntry->FileName, OCC::Utility::convertSizeToInt(len));
// Unless the file was removed or renamed, get its full long name
// TODO: We could still try expanding the path in the tricky cases...
QString longfile = file;
if (curEntry->Action != FILE_ACTION_REMOVED
&& curEntry->Action != FILE_ACTION_RENAMED_OLD_NAME) {
size_t longNameSize = GetLongPathNameW(reinterpret_cast<LPCWSTR>(file.utf16()), fileNameBuffer, fileNameBufferSize);
if (longNameSize > 0) {
longfile = QString::fromUtf16(reinterpret_cast<const ushort *>(fileNameBuffer), OCC::Utility::convertSizeToInt(longNameSize));
} else {
qCWarning(lcFolderWatcher) << "Error converting file name to full length, keeping original name.";
}
}
longfile = QDir::cleanPath(longfile);
// Skip modifications of folders: One of these is triggered for changes
// and new files in a folder, probably because of the folder's mtime
// changing. We don't need them.
bool skip = curEntry->Action == FILE_ACTION_MODIFIED
&& QFileInfo(longfile).isDir();
if (!skip) {
emit changed(longfile);
}
if (curEntry->NextEntryOffset == 0) {
break;
}
curEntry = (FILE_NOTIFY_INFORMATION *)((char *)curEntry + curEntry->NextEntryOffset);
}
}
CancelIo(_directory);
closeHandle();
}
void WatcherThread::closeHandle()
{
if (_directory) {
CloseHandle(_directory);
_directory = nullptr;
}
}
void WatcherThread::run()
{
_resultEvent = CreateEvent(nullptr, true, false, nullptr);
_stopEvent = CreateEvent(nullptr, true, false, nullptr);
// If this buffer fills up before we've extracted its data we will lose
// change information. Therefore start big.
size_t bufferSize = 4096 * 10;
size_t maxBuffer = 64 * 1024;
while (!_done) {
bool increaseBufferSize = false;
watchChanges(bufferSize, &increaseBufferSize);
if (increaseBufferSize) {
bufferSize = qMin(bufferSize * 2, maxBuffer);
} else if (!_done) {
// Other errors shouldn't actually happen,
// so sleep a bit to avoid running into the same error case in a
// tight loop.
sleep(2);
}
}
}
WatcherThread::~WatcherThread()
{
closeHandle();
}
void WatcherThread::stop()
{
_done = 1;
SetEvent(_stopEvent);
}
FolderWatcherPrivate::FolderWatcherPrivate(FolderWatcher *p, const QString &path)
: _parent(p)
{
_thread = new WatcherThread(path);
connect(_thread, SIGNAL(changed(const QString &)),
_parent, SLOT(changeDetected(const QString &)));
connect(_thread, SIGNAL(lostChanges()),
_parent, SIGNAL(lostChanges()));
_thread->start();
}
FolderWatcherPrivate::~FolderWatcherPrivate()
{
_thread->stop();
_thread->wait();
delete _thread;
}
} // namespace OCC
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