gecko-dev/xpcom/glue/FileUtils.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** 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 code.
*
* The Initial Developer of the Original Code is
* Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2010
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Benjamin Smedberg <benjamin@smedbergs.us>
* Taras Glek <tglek@mozilla.com>
*
* 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 ***** */
#ifndef mozilla_FileUtils_h
#define mozilla_FileUtils_h
#if defined(XP_UNIX)
# include <unistd.h>
#elif defined(XP_WIN)
# include <io.h>
#endif
#include "prio.h"
namespace mozilla {
/**
* AutoFDClose is a RAII wrapper for PRFileDesc.
**/
class AutoFDClose
{
public:
AutoFDClose(PRFileDesc* fd = nsnull) : mFD(fd) { }
~AutoFDClose() { if (mFD) PR_Close(mFD); }
PRFileDesc* operator= (PRFileDesc *fd) {
if (mFD) PR_Close(mFD);
mFD = fd;
return fd;
}
operator PRFileDesc* () { return mFD; }
PRFileDesc** operator &() { *this = nsnull; return &mFD; }
private:
PRFileDesc *mFD;
};
/**
* Instances close() their fds when they go out of scope.
*/
struct ScopedClose
{
ScopedClose(int aFd=-1) : mFd(aFd) {}
~ScopedClose() {
if (0 <= mFd) {
close(mFd);
}
}
int mFd;
};
/**
* Fallocate efficiently and continuously allocates files via fallocate-type APIs.
* This is useful for avoiding fragmentation.
* On sucess the file be padded with zeros to grow to aLength.
*
* @param aFD file descriptor.
* @param aLength length of file to grow to.
* @return true on success.
*/
NS_COM_GLUE bool fallocate(PRFileDesc *aFD, PRInt64 aLength);
} // namespace mozilla
#endif