common/vfs/vfsmemory.cpp

	vfsmemory.cpp revision 985524f3b29e0f50c596635c16fae80bc78dcc45
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/* $Id$ */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/** @file
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * IPRT - Virtual File System, Memory Backed VFS.
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/*
b72d3233df38e3122eda39b39a27b35c27209615vboxsync * Copyright (C) 2010 Oracle Corporation
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync *
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * This file is part of VirtualBox Open Source Edition (OSE), as
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * available from http://www.virtualbox.org. This file is free software;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * you can redistribute it and/or modify it under the terms of the GNU
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * General Public License (GPL) as published by the Free Software
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * Foundation, in version 2 as it comes in the "COPYING" file of the
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync *
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * The contents of this file may alternatively be used under the terms
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * of the Common Development and Distribution License Version 1.0
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * VirtualBox OSE distribution, in which case the provisions of the
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * CDDL are applicable instead of those of the GPL.
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync *
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * You may elect to license modified versions of this file under the
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * terms and conditions of either the GPL or the CDDL or both.
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/*******************************************************************************
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync*   Header Files                                                               *
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync*******************************************************************************/
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync#include "internal/iprt.h"
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync#include <iprt/vfs.h>
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync#include <iprt/asm.h>
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync#include <iprt/assert.h>
230bd8589bba39933ac5ec21482d6186d675e604vboxsync#include <iprt/err.h>
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync#include <iprt/file.h>
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync#include <iprt/list.h>
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync#include <iprt/poll.h>
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync#include <iprt/string.h>
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync#include <iprt/vfslowlevel.h>
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync
b72d3233df38e3122eda39b39a27b35c27209615vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync/*******************************************************************************
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync*   Header Files                                                               *
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync*******************************************************************************/
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync#include "internal/iprt.h"
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync#include <iprt/vfs.h>
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync#include <iprt/err.h>
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync#include <iprt/mem.h>
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync/*******************************************************************************
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync*   Defined Constants And Macros                                               *
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync*******************************************************************************/
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync/** The max extent size. */
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync#define RTVFSMEM_MAX_EXTENT_SIZE    _2M
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync/*******************************************************************************
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync*   Structures and Typedefs                                                    *
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync*******************************************************************************/
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync/**
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync * Memory base object info.
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsynctypedef struct RTVFSMEMBASE
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync{
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    /** The basic object info. */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    RTFSOBJINFO         ObjInfo;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync} RTVFSMEMBASE;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync/**
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * Memory file extent.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync *
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * This stores part of the file content.
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsynctypedef struct RTVFSMEMEXTENT
230bd8589bba39933ac5ec21482d6186d675e604vboxsync{
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    /** Extent list entry. */
230bd8589bba39933ac5ec21482d6186d675e604vboxsync    RTLISTNODE          Entry;
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    /** The offset of this extent within the file. */
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    uint64_t            off;
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    /** The size of the this extent. */
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    uint32_t            cb;
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    /** The data. */
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    uint8_t             abData[1];
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync} RTVFSMEMEXTENT;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/** Pointer to a memory file extent. */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsynctypedef RTVFSMEMEXTENT *PRTVFSMEMEXTENT;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/**
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * Memory file.
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsynctypedef struct RTVFSMEMFILE
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync{
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    /** The base info. */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    RTVFSMEMBASE        Base;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    /** The current file position. */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    uint64_t            offCurPos;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    /** Pointer to the current file extent. */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    PRTVFSMEMEXTENT     pCurExt;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    /** Linked list of file extents - RTVFSMEMEXTENT. */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    RTLISTNODE          ExtentHead;
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    /** The current extent size.
0368e9c310393e82ef37c480b6acbd0f107cf0edvboxsync     * This is slowly grown to RTVFSMEM_MAX_EXTENT_SIZE as the file grows.  */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    uint32_t            cbExtent;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync} RTVFSMEMFILE;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/** Pointer to a memory file. */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsynctypedef RTVFSMEMFILE *PRTVFSMEMFILE;
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/**
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync * @interface_method_impl{RTVFSOBJOPS,pfnClose}
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync */
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsyncstatic DECLCALLBACK(int) rtVfsMemFile_Close(void *pvThis)
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync{
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    /*
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync     * Free the extent list.
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync     */
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync    PRTVFSMEMEXTENT pCur, pNext;
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync    RTListForEachSafe(&pThis->ExtentHead, pCur, pNext, RTVFSMEMEXTENT, Entry)
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync    {
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync        pCur->off       = RTFOFF_MAX;
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync        pCur->cb        = UINT32_MAX;
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync        RTListNodeRemove(&pCur->Entry);
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync        RTMemFree(pCur);
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    }
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    pThis->pCurExt = NULL;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    return VINF_SUCCESS;
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync}
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync/**
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * @interface_method_impl{RTVFSOBJOPS,pfnQueryInfo}
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsyncstatic DECLCALLBACK(int) rtVfsMemFile_QueryInfo(void *pvThis, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr)
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync{
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    switch (enmAddAttr)
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    {
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync        case RTFSOBJATTRADD_NOTHING:
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync        case RTFSOBJATTRADD_UNIX:
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync            *pObjInfo = pThis->Base.ObjInfo;
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync            return VINF_SUCCESS;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync        default:
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync            return VERR_NOT_SUPPORTED;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    }
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync}
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync/**
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync * The slow paths of rtVfsMemFile_LocateExtent.
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync *
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync * @copydoc rtVfsMemFile_LocateExtent
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsyncstatic PRTVFSMEMEXTENT rtVfsMemFile_LocateExtentSlow(PRTVFSMEMFILE pThis, uint64_t off, bool *pfHit)
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync{
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    /*
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync     * Search from the start or the previously used extent.  The heuristics
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync     * are very very simple, but whatever.
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync     */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    PRTVFSMEMEXTENT pExtent = pThis->pCurExt;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    if (!pExtent || pExtent->off < off)
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    {
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync        pExtent = RTListGetFirst(&pThis->ExtentHead, RTVFSMEMEXTENT, Entry);
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync        if (!pExtent)
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync        {
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync            *pfHit = false;
d1c36fd86d36726777e3d6f9d040573e0aaf30devboxsync            return NULL;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync        }
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    }
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    while (off - pExtent->off >= pExtent->cb)
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    {
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync        Assert(pExtent->off <= off);
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync        PRTVFSMEMEXTENT pNext = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync        if (   !pNext
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync            || pNext->off > off)
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync        {
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync            *pfHit = false;
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync            return pExtent;
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync        }
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync        pExtent = pNext;
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    }
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    *pfHit = true;
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync    pThis->pCurExt = pExtent;
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync    return pExtent;
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync}
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync/**
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync * Locates the extent covering the specified offset, or then one before it.
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync *
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync * @returns The closest extent.  NULL if off is 0 and there are no extent
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync *          covering byte 0 yet.
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync * @param   pThis               The memory file.
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync * @param   off                 The offset (0-positive).
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync * @param   pfHit               Where to indicate whether the extent is a
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync *                              direct hit (@c true) or just a closest match
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync *                              (@c false).
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync */
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsyncDECLINLINE(PRTVFSMEMEXTENT) rtVfsMemFile_LocateExtent(PRTVFSMEMFILE pThis, uint64_t off, bool *pfHit)
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync{
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    /*
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync     * The most likely case is that we're hitting the extent we used in the
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync     * previous access or the one immediately following it.
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync     */
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    PRTVFSMEMEXTENT pExtent = pThis->pCurExt;
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync    if (!pExtent)
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync        return rtVfsMemFile_LocateExtentSlow(pThis, off, pfHit);
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync    if (off - pExtent->off >= pExtent->cb)
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync    {
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync        pExtent = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync        if (   !pExtent
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync            || off - pExtent->off >= pExtent->cb)
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync            return rtVfsMemFile_LocateExtentSlow(pThis, off, pfHit);
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync        pThis->pCurExt = pExtent;
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync    }
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync    *pfHit = true;
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync    return pExtent;
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync}
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync
b72d3233df38e3122eda39b39a27b35c27209615vboxsync/**
b72d3233df38e3122eda39b39a27b35c27209615vboxsync * @interface_method_impl{RTVFSIOSTREAMOPS,pfnRead}
5981e6935987b08737b730b63a41acc1dd696377vboxsync */
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsyncstatic DECLCALLBACK(int) rtVfsMemFile_Read(void *pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t *pcbRead)
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync{
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    Assert(pSgBuf->cSegs == 1);
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    Assert(off < 0);
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    NOREF(fBlocking);
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    /*
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync     * Find the current position and check if it's within the file.
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync     */
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    uint64_t offUnsigned = off < 0 ? pThis->offCurPos : (uint64_t)off;
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    if (offUnsigned >= (uint64_t)pThis->Base.ObjInfo.cbObject)
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync    {
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync        if (pcbRead)
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        {
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync            *pcbRead = 0;
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync            pThis->offCurPos = offUnsigned;
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync            return VINF_EOF;
39c2eccedfdb7455c52225543c355e33a65f0c81vboxsync        }
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        return VERR_EOF;
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    }
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    size_t cbLeftToRead;
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    if (offUnsigned + pSgBuf->paSegs[0].cbSeg > (uint64_t)pThis->Base.ObjInfo.cbObject)
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    {
b35e3948f1287430503b6b432945b8cf4bfd3a23vboxsync        if (!pcbRead)
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync            return VERR_EOF;
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        *pcbRead = cbLeftToRead = (size_t)((uint64_t)pThis->Base.ObjInfo.cbObject - offUnsigned);
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    }
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    else
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    {
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        cbLeftToRead = pSgBuf->paSegs[0].cbSeg;
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        if (pcbRead)
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync            *pcbRead = cbLeftToRead;
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    }
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    /*
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync     * Ok, we've got a valid stretch within the file.  Do the reading.
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync     */
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    if (cbLeftToRead > 0)
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync    {
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        uint8_t        *pbDst   = (uint8_t *)pSgBuf->paSegs[0].pvSeg;
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        bool            fHit;
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        PRTVFSMEMEXTENT pExtent = rtVfsMemFile_LocateExtent(pThis, offUnsigned, &fHit);
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        for (;;)
d8dee9a7ef33d4c705d5fd087d5af9c7cb071f85vboxsync        {
0612e2adbcc146b9eb7748983c720e35e38d0dc9vboxsync            PRTVFSMEMEXTENT pNext;
e2a73964f463b9e91f6f096f9e15974a3edcc416vboxsync            size_t          cbThisRead;
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync            Assert(!pExtent || pExtent->off <= offUnsigned);
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            /*
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync             * Do we hit an extent covering the the current file surface?
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync             */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            if (fHit)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                size_t const offExtent = (size_t)(offUnsigned - pExtent->off);
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync                cbThisRead = pExtent->cb - offExtent;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                if (cbThisRead >= cbLeftToRead)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                    cbThisRead = cbLeftToRead;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                memcpy(pbDst, &pExtent->abData[offUnsigned - pExtent->off], cbThisRead);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                offUnsigned  += cbThisRead;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                cbLeftToRead -= cbThisRead;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                if (!cbLeftToRead)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                    break;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                pbDst        += cbThisRead;
aace59ca7fd1b66174593c5a564878cfac89e11evboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                pNext = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                if (   pNext
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                    && pNext->off == pExtent->off + pExtent->cb)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                    pExtent = pNext;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                    continue;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                fHit = false;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync             * No extent of this portion (sparse file).
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync             */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            else if (pExtent)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                pNext = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            else
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                pNext = NULL;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            Assert(!pNext || pNext->off > pExtent->off);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            if (   !pNext
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync                || offUnsigned + cbLeftToRead <= pNext->off)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                cbThisRead = cbLeftToRead;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            else
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync                cbThisRead = (size_t)(pNext->off - offUnsigned);
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            RT_BZERO(pbDst, cbThisRead);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            offUnsigned  += cbThisRead;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            cbLeftToRead -= cbThisRead;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            if (!cbLeftToRead)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                break;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            pbDst        += cbThisRead;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            /* Go on and read content from the next extent. */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            fHit     = true;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            pExtent  = pNext;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    pThis->offCurPos = offUnsigned;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    return VINF_SUCCESS;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync}
aace59ca7fd1b66174593c5a564878cfac89e11evboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync/**
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * Allocates a new extent covering the ground at @a offUnsigned.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync *
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * @returns Pointer to the new extent on success, NULL if we're out of memory.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * @param   pThis               The memory file.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * @param   offUnsigned         The location to allocate the extent at.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * @param   cbToWrite           The number of bytes we're interested in writing
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync *                              starting at @a offUnsigned.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * @param   pPrev               The extention before @a offUnsigned.  NULL if
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync *                              none.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsyncstatic PRTVFSMEMEXTENT rtVfsMemFile_AllocExtent(PRTVFSMEMFILE pThis, uint64_t offUnsigned, size_t cbToWrite,
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                                                PRTVFSMEMEXTENT pPrev)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync{
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     * Adjust the extent size if we haven't reached the max size yet.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    if (pThis->cbExtent != RTVFSMEM_MAX_EXTENT_SIZE)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        if (cbToWrite >= RTVFSMEM_MAX_EXTENT_SIZE)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            pThis->cbExtent = RTVFSMEM_MAX_EXTENT_SIZE;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        else if (!RTListIsEmpty(&pThis->ExtentHead))
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        {
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync            uint32_t cbNextExtent = pThis->cbExtent;
683eff3070b1b86fe71b71af7fda82766ea19d17vboxsync            if (RT_IS_POWER_OF_TWO(cbNextExtent))
b72d3233df38e3122eda39b39a27b35c27209615vboxsync                cbNextExtent *= 2;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            else
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                /* Make it a power of two (seeRTVfsMemorizeIoStreamAsFile). */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                cbNextExtent = _4K;
b72d3233df38e3122eda39b39a27b35c27209615vboxsync                while (cbNextExtent < pThis->cbExtent)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                    cbNextExtent *= 2;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            if (((pThis->Base.ObjInfo.cbAllocated + cbNextExtent) & (cbNextExtent - 1)) == 0)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                pThis->cbExtent = cbNextExtent;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     * Figure out the size and position of the extent we're adding.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    uint64_t        offExtent = offUnsigned & ~(uint64_t)(pThis->cbExtent - 1);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    uint32_t        cbExtent  = pThis->cbExtent;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    uint64_t const  offPrev   = pPrev ? pPrev->off + pPrev->cb : 0;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    if (offExtent < offPrev)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        offExtent = offPrev;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    PRTVFSMEMEXTENT pNext     = pPrev
aace59ca7fd1b66174593c5a564878cfac89e11evboxsync                              ? RTListGetNext(&pThis->ExtentHead, pPrev, RTVFSMEMEXTENT, Entry)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                              : RTListGetFirst(&pThis->ExtentHead, RTVFSMEMEXTENT, Entry);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    if (pNext)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        uint64_t cbMaxExtent = pNext->off - offExtent;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        if (cbMaxExtent < cbExtent)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            cbExtent = (uint32_t)cbMaxExtent;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     * Allocate, initialize and insert the new extent.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    PRTVFSMEMEXTENT pNew = (PRTVFSMEMEXTENT)RTMemAllocZ(RT_OFFSETOF(RTVFSMEMEXTENT, abData[cbExtent]));
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    if (pNew)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        pNew->off = offExtent;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        pNew->cb  = cbExtent;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        if (pPrev)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            RTListNodeInsertAfter(&pPrev->Entry, &pNew->Entry);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        else
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            RTListPrepend(&pThis->ExtentHead, &pNew->Entry);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        pThis->Base.ObjInfo.cbAllocated += cbExtent;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    /** @todo retry with minimum size. */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    return pNew;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync}
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync/**
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * @interface_method_impl{RTVFSIOSTREAMOPS,pfnWrite}
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsyncstatic DECLCALLBACK(int) rtVfsMemFile_Write(void *pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t *pcbWritten)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync{
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    Assert(pSgBuf->cSegs == 1);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    Assert(off < 0);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    NOREF(fBlocking);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     * Validate the write and set up the write loop.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     */
aace59ca7fd1b66174593c5a564878cfac89e11evboxsync    size_t          cbLeftToWrite = pSgBuf->paSegs[0].cbSeg;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    if (!cbLeftToWrite)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        return VINF_SUCCESS; /* pcbWritten is already 0. */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    uint64_t        offUnsigned = off < 0 ? pThis->offCurPos : (uint64_t)off;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    if (offUnsigned + cbLeftToWrite >= (uint64_t)RTFOFF_MAX)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        return VERR_OUT_OF_RANGE;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    int             rc      = VINF_SUCCESS;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    uint8_t const  *pbSrc   = (uint8_t const *)pSgBuf->paSegs[0].pvSeg;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    bool            fHit;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    PRTVFSMEMEXTENT pExtent = rtVfsMemFile_LocateExtent(pThis, offUnsigned, &fHit);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    for (;;)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync         * If we didn't hit an extent, allocate one (unless it's all zeros).
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync         */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        if (!fHit)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            Assert(!pExtent || (pExtent->off < offUnsigned && pExtent->off + pExtent->cb <= offUnsigned));
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            /* Skip leading zeros if there is a whole bunch of them. */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            uint8_t const *pbSrcNZ = (uint8_t const *)ASMMemIsAll8(pbSrc, cbLeftToWrite, 0);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            if (!pbSrcNZ)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                offUnsigned  += cbLeftToWrite;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                cbLeftToWrite = 0;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                break;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            size_t const cbZeros = pbSrcNZ - pbSrc;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            if (cbZeros >= RT_MIN(pThis->cbExtent, _64K))
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                offUnsigned   += cbZeros;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                cbLeftToWrite -= cbZeros;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                pbSrc          = pbSrcNZ;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                pExtent = rtVfsMemFile_LocateExtent(pThis, offUnsigned, &fHit);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                break;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            fHit    = true;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            pExtent = rtVfsMemFile_AllocExtent(pThis, offUnsigned, cbLeftToWrite, pExtent);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            if (!pExtent)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                rc = VERR_NO_MEMORY;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                break;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            }
aace59ca7fd1b66174593c5a564878cfac89e11evboxsync        }
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync         * Copy the source data into the current extent.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync         */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        uint32_t const  offDst      = (uint32_t)(offUnsigned - pExtent->off);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        uint32_t        cbThisWrite = pExtent->cb - offDst;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        if (cbThisWrite > cbLeftToWrite)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            cbThisWrite = (uint32_t)cbLeftToWrite;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        memcpy(&pExtent->abData[offDst], pbSrc, cbThisWrite);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        offUnsigned   += cbLeftToWrite;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        cbLeftToWrite -= cbThisWrite;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        if (!cbLeftToWrite)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            break;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        pbSrc += cbThisWrite;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        Assert(offUnsigned == pExtent->off + pExtent->cb);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync         * Advance to the next extent.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync         */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        PRTVFSMEMEXTENT pNext = RTListGetNext(&pThis->ExtentHead, pExtent, RTVFSMEMEXTENT, Entry);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        Assert(!pNext || pNext->off >= offUnsigned);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        if (pNext && pNext->off == offUnsigned)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            pExtent = pNext;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        else
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync            fHit = false;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    }
b72d3233df38e3122eda39b39a27b35c27209615vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    /*
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     * Update the state, set return value and return.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     * Note! There must be no alternative exit path from the loop above.
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync     */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    pThis->offCurPos = offUnsigned;
b72d3233df38e3122eda39b39a27b35c27209615vboxsync    if ((uint64_t)pThis->Base.ObjInfo.cbObject < offUnsigned)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        pThis->Base.ObjInfo.cbObject = offUnsigned;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    if (pcbWritten)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        *pcbWritten = pSgBuf->paSegs[0].cbSeg - cbLeftToWrite;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    return rc;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync}
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync/**
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * @interface_method_impl{RTVFSIOSTREAMOPS,pfnFlush}
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync */
aace59ca7fd1b66174593c5a564878cfac89e11evboxsyncstatic DECLCALLBACK(int) rtVfsMemFile_Flush(void *pvThis)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync{
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    NOREF(pvThis);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    return VINF_SUCCESS;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync}
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync/**
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync * @interface_method_impl{RTVFSIOSTREAMOPS,pfnPollOne}
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync */
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsyncstatic DECLCALLBACK(int) rtVfsMemFile_PollOne(void *pvThis, uint32_t fEvents, RTMSINTERVAL cMillies, bool fIntr,
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync                                              uint32_t *pfRetEvents)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync{
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    int           rc;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    if (fEvents != RTPOLL_EVT_ERROR)
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    {
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        *pfRetEvents = fEvents & ~RTPOLL_EVT_ERROR;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        rc = VINF_SUCCESS;
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    }
b72d3233df38e3122eda39b39a27b35c27209615vboxsync    else
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync        rc = RTVfsUtilDummyPollOne(fEvents, cMillies, fIntr, pfRetEvents);
9b456547aefb8a2e8f5600eba9ec377dbc9b4475vboxsync    return rc;
b72d3233df38e3122eda39b39a27b35c27209615vboxsync}
b72d3233df38e3122eda39b39a27b35c27209615vboxsync
b72d3233df38e3122eda39b39a27b35c27209615vboxsync
b72d3233df38e3122eda39b39a27b35c27209615vboxsync/**
b72d3233df38e3122eda39b39a27b35c27209615vboxsync * @interface_method_impl{RTVFSIOSTREAMOPS,pfnTell}
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync */
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsyncstatic DECLCALLBACK(int) rtVfsMemFile_Tell(void *pvThis, PRTFOFF poffActual)
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync{
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    *poffActual = pThis->offCurPos;
84f746c9015f34e9ab096b87e063d0d6ab7fc7aevboxsync    return VINF_SUCCESS;
}


/**
 * @interface_method_impl{RTVFSOBJSETOPS,pfnMode}
 */
static DECLCALLBACK(int) rtVfsMemFile_SetMode(void *pvThis, RTFMODE fMode, RTFMODE fMask)
{
    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
    pThis->Base.ObjInfo.Attr.fMode = (pThis->Base.ObjInfo.Attr.fMode & ~fMask) | fMode;
    return VINF_SUCCESS;
}


/**
 * @interface_method_impl{RTVFSOBJSETOPS,pfnSetTimes}
 */
static DECLCALLBACK(int) rtVfsMemFile_SetTimes(void *pvThis, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
                                               PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
{
    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;

    if (pAccessTime)
        pThis->Base.ObjInfo.AccessTime          = *pAccessTime;
    if (pModificationTime)
        pThis->Base.ObjInfo.ModificationTime    = *pModificationTime;
    if (pChangeTime)
        pThis->Base.ObjInfo.ChangeTime          = *pChangeTime;
    if (pBirthTime)
        pThis->Base.ObjInfo.BirthTime           = *pBirthTime;

    return VINF_SUCCESS;
}


/**
 * @interface_method_impl{RTVFSOBJSETOPS,pfnSetOwner}
 */
static DECLCALLBACK(int) rtVfsMemFile_SetOwner(void *pvThis, RTUID uid, RTGID gid)
{
    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;

    if (uid != NIL_RTUID)
        pThis->Base.ObjInfo.Attr.u.Unix.uid = uid;
    if (gid != NIL_RTUID)
        pThis->Base.ObjInfo.Attr.u.Unix.gid = gid;

    return VINF_SUCCESS;
}


/**
 * @interface_method_impl{RTVFSFILEOPS,pfnSeek}
 */
static DECLCALLBACK(int) rtVfsMemFile_Seek(void *pvThis, RTFOFF offSeek, unsigned uMethod, PRTFOFF poffActual)
{
    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;

    /*
     * Seek relative to which position.
     */
    uint64_t offWrt;
    switch (uMethod)
    {
        case RTFILE_SEEK_BEGIN:
            offWrt = 0;
            break;

        case RTFILE_SEEK_CURRENT:
            offWrt = pThis->offCurPos;
            break;

        case RTFILE_SEEK_END:
            offWrt = pThis->Base.ObjInfo.cbObject;
            break;

        default:
            return VERR_INTERNAL_ERROR_5;
    }

    /*
     * Calc new position, take care to stay without bounds.
     */
    uint64_t offNew;
    if (offSeek == 0)
        offNew = offWrt;
    else if (offSeek > 0)
    {
        offNew = offWrt + offSeek;
        if (   offNew < offWrt
            || offNew > RTFOFF_MAX)
            offNew = RTFOFF_MAX;
    }
    else if ((uint64_t)-offSeek < offWrt)
        offNew = offWrt + offSeek;
    else
        offNew = 0;

    /*
     * Update the state and set return value.
     */
    if (   pThis->pCurExt
        && pThis->pCurExt->off - offNew >= pThis->pCurExt->cb)
        pThis->pCurExt = NULL;
    pThis->offCurPos = offNew;

    *poffActual = offNew;
    return VINF_SUCCESS;
}


/**
 * @interface_method_impl{RTVFSFILEOPS,pfnQuerySize}
 */
static DECLCALLBACK(int) rtVfsMemFile_QuerySize(void *pvThis, uint64_t *pcbFile)
{
    PRTVFSMEMFILE pThis = (PRTVFSMEMFILE)pvThis;
    *pcbFile = pThis->Base.ObjInfo.cbObject;
    return VINF_SUCCESS;
}


/**
 * Standard file operations.
 */
DECLHIDDEN(const RTVFSFILEOPS) g_rtVfsStdFileOps =
{
    { /* Stream */
        { /* Obj */
            RTVFSOBJOPS_VERSION,
            RTVFSOBJTYPE_FILE,
            "MemFile",
            rtVfsMemFile_Close,
            rtVfsMemFile_QueryInfo,
            RTVFSOBJOPS_VERSION
        },
        RTVFSIOSTREAMOPS_VERSION,
        RTVFSIOSTREAMOPS_FEAT_NO_SG,
        rtVfsMemFile_Read,
        rtVfsMemFile_Write,
        rtVfsMemFile_Flush,
        rtVfsMemFile_PollOne,
        rtVfsMemFile_Tell,
        NULL /*Skip*/,
        NULL /*ZeroFill*/,
        RTVFSIOSTREAMOPS_VERSION,
    },
    RTVFSFILEOPS_VERSION,
    /*RTVFSIOFILEOPS_FEAT_NO_AT_OFFSET*/ 0,
    { /* ObjSet */
        RTVFSOBJSETOPS_VERSION,
        RT_OFFSETOF(RTVFSFILEOPS, Stream.Obj) - RT_OFFSETOF(RTVFSFILEOPS, ObjSet),
        rtVfsMemFile_SetMode,
        rtVfsMemFile_SetTimes,
        rtVfsMemFile_SetOwner,
        RTVFSOBJSETOPS_VERSION
    },
    rtVfsMemFile_Seek,
    rtVfsMemFile_QuerySize,
    RTVFSFILEOPS_VERSION
};


RTDECL(int) RTVfsMemorizeIoStreamAsFile(RTVFSIOSTREAM hVfsIos, uint32_t fFlags, PRTVFSFILE phVfsFile)
{
    /*
     * Create a memory file instance and try set the extension size to match
     * the length of the I/O stream.
     */
    RTFSOBJINFO ObjInfo;
    int rc = RTVfsIoStrmQueryInfo(hVfsIos, &ObjInfo, RTFSOBJATTRADD_UNIX);
    if (RT_SUCCESS(rc))
    {
        RTVFSFILE       hVfsFile;
        PRTVFSMEMFILE   pThis;
        rc = RTVfsNewFile(&g_rtVfsStdFileOps, sizeof(*pThis), fFlags | RTFILE_O_WRITE, NIL_RTVFS, NIL_RTVFSLOCK,
                          &hVfsFile, (void **)&pThis);
        if (RT_SUCCESS(rc))
        {
            pThis->Base.ObjInfo = ObjInfo;
            pThis->offCurPos    = 0;
            pThis->pCurExt      = NULL;
            RTListInit(&pThis->ExtentHead);
            if (ObjInfo.cbObject <= 0)
                pThis->cbExtent = _4K;
            else if (ObjInfo.cbObject < RTVFSMEM_MAX_EXTENT_SIZE)
                pThis->cbExtent = _4K /* ObjInfo.cbObject */;
            else
                pThis->cbExtent = RTVFSMEM_MAX_EXTENT_SIZE;

            /*
             * Copy the stream.
             */
            RTVFSIOSTREAM hVfsIosDst = RTVfsFileToIoStream(hVfsFile);
            rc = RTVfsUtilPumpIoStreams(hVfsIos, hVfsIosDst, pThis->cbExtent);
            RTVfsIoStrmRelease(hVfsIosDst);
            if (RT_SUCCESS(rc))
            {
                pThis->pCurExt   = RTListGetFirst(&pThis->ExtentHead, RTVFSMEMEXTENT, Entry);
                pThis->offCurPos = 0;

                if (!(fFlags & RTFILE_O_WRITE))
                {
                    /** @todo clear RTFILE_O_WRITE from the resulting. */
                }
                *phVfsFile = hVfsFile;
                return VINF_SUCCESS;
            }
            RTVfsFileRelease(hVfsFile);
        }
    }
    return rc;
}