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+/** @file
+ * IPRT - Virtual Filesystem.
+ */
+
+/*
+ * Copyright (C) 2010-2019 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+#ifndef IPRT_INCLUDED_vfs_h
+#define IPRT_INCLUDED_vfs_h
+#ifndef RT_WITHOUT_PRAGMA_ONCE
+# pragma once
+#endif
+
+#include <iprt/cdefs.h>
+#include <iprt/types.h>
+#include <iprt/dir.h>
+#include <iprt/fs.h>
+#include <iprt/handle.h>
+#include <iprt/symlink.h>
+#include <iprt/sg.h>
+#include <iprt/time.h>
+
+
+RT_C_DECLS_BEGIN
+
+/** @defgroup grp_rt_vfs RTVfs - Virtual Filesystem
+ * @ingroup grp_rt
+ *
+ * The virtual filesystem APIs are intended to make it possible to work on
+ * container files, file system sub-trees, file system overlays and other custom
+ * filesystem configurations. It also makes it possible to create filters, like
+ * automatically gunzipping a tar.gz file before feeding it to the RTTar API for
+ * unpacking - or wise versa.
+ *
+ * The virtual filesystem APIs are intended to mirror the RTDir, RTFile, RTPath
+ * and RTFs APIs pretty closely so that rewriting a piece of code to work with
+ * it should be easy. However there are some differences to the way the APIs
+ * works and the user should heed the documentation. The differences are
+ * usually motivated by simplification and in some case to make the VFS more
+ * flexible.
+ *
+ * @{
+ */
+
+/**
+ * The object type.
+ */
+typedef enum RTVFSOBJTYPE
+{
+ /** Invalid type. */
+ RTVFSOBJTYPE_INVALID = 0,
+ /** Pure base object.
+ * This is returned by the filesystem stream to represent directories,
+ * devices, fifos and similar that needs to be created. */
+ RTVFSOBJTYPE_BASE,
+ /** Virtual filesystem. */
+ RTVFSOBJTYPE_VFS,
+ /** Filesystem stream. */
+ RTVFSOBJTYPE_FS_STREAM,
+ /** Pure I/O stream. */
+ RTVFSOBJTYPE_IO_STREAM,
+ /** Directory. */
+ RTVFSOBJTYPE_DIR,
+ /** File. */
+ RTVFSOBJTYPE_FILE,
+ /** Symbolic link. */
+ RTVFSOBJTYPE_SYMLINK,
+ /** End of valid object types. */
+ RTVFSOBJTYPE_END,
+ /** Pure I/O stream. */
+ RTVFSOBJTYPE_32BIT_HACK = 0x7fffffff
+} RTVFSOBJTYPE;
+/** Pointer to a VFS object type. */
+typedef RTVFSOBJTYPE *PRTVFSOBJTYPE;
+
+
+
+/** @name RTVfsCreate flags
+ * @{ */
+/** Whether the file system is read-only. */
+#define RTVFS_C_READONLY RT_BIT(0)
+/** Whether we the VFS should be thread safe (i.e. automaticaly employ
+ * locks). */
+#define RTVFS_C_THREAD_SAFE RT_BIT(1)
+/** @} */
+
+/**
+ * Creates an empty virtual filesystem.
+ *
+ * @returns IPRT status code.
+ * @param pszName Name, for logging and such.
+ * @param fFlags Flags, MBZ.
+ * @param phVfs Where to return the VFS handle. Release the returned
+ * reference by calling RTVfsRelease.
+ */
+RTDECL(int) RTVfsCreate(const char *pszName, uint32_t fFlags, PRTVFS phVfs);
+RTDECL(uint32_t) RTVfsRetain(RTVFS hVfs);
+RTDECL(uint32_t) RTVfsRetainDebug(RTVFS hVfs, RT_SRC_POS_DECL);
+RTDECL(uint32_t) RTVfsRelease(RTVFS hVfs);
+
+/** @name RTVFSMNT_F_XXX - Flags for RTVfsMount
+ * @{ */
+/** Mount read-only. */
+#define RTVFSMNT_F_READ_ONLY RT_BIT_32(0)
+/** Purpose is . */
+#define RTVFSMNT_F_FOR_RANGE_IN_USE RT_BIT_32(1)
+/** Valid mask. */
+#define RTVFSMNT_F_VALID_MASK UINT32_C(0x00000003)
+/** @} */
+
+/**
+ * Does the file system detection and mounting.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_VFS_UNSUPPORTED_FORMAT if not recognized as a support file
+ * system.
+ * @param hVfsFileIn The file handle of the volume.
+ * @param fFlags RTVFSMTN_F_XXX.
+ * @param phVfs Where to return the VFS handle on success.
+ * @param pErrInfo Where to return additional error information.
+ * Optional.
+ */
+RTDECL(int) RTVfsMountVol(RTVFSFILE hVfsFileIn, uint32_t fFlags, PRTVFS phVfs, PRTERRINFO pErrInfo);
+
+RTDECL(int) RTVfsAttach(RTVFS hVfs, const char *pszMountPoint, uint32_t fFlags, RTVFS hVfsAttach);
+RTDECL(int) RTVfsDetach(RTVFS hVfs, const char *pszMountPoint, RTVFS hVfsToDetach, PRTVFS *phVfsDetached);
+RTDECL(uint32_t) RTVfsGetAttachmentCount(RTVFS hVfs);
+RTDECL(int) RTVfsGetAttachment(RTVFS hVfs, uint32_t iOrdinal, PRTVFS *phVfsAttached, uint32_t *pfFlags,
+ char *pszMountPoint, size_t cbMountPoint);
+
+/**
+ * Opens the root director of the given VFS.
+ *
+ * @returns IPRT status code.
+ * @param hVfs VFS handle.
+ * @param phDir Where to return the root directory handle.
+ */
+RTDECL(int) RTVfsOpenRoot(RTVFS hVfs, PRTVFSDIR phDir);
+
+/**
+ * Queries information about a object in the virtual filesystem.
+ *
+ * @returns IPRT Status code.
+ * @param hVfs VFS handle.
+ * @param pszPath Path to the object, relative to the VFS root.
+ * @param pObjInfo Where to return info.
+ * @param enmAddAttr What to return.
+ * @param fFlags RTPATH_F_XXX.
+ * @sa RTPathQueryInfoEx, RTVfsDirQueryPathInfo, RTVfsObjQueryInfo
+ */
+RTDECL(int) RTVfsQueryPathInfo(RTVFS hVfs, const char *pszPath, PRTFSOBJINFO pObjInfo,
+ RTFSOBJATTRADD enmAddAttr, uint32_t fFlags);
+
+/**
+ * Checks whether a given range is in use by the virtual filesystem.
+ *
+ * @returns IPRT status code.
+ * @param hVfs VFS handle.
+ * @param off Start offset to check.
+ * @param cb Number of bytes to check.
+ * @param pfUsed Where to store the result.
+ */
+RTDECL(int) RTVfsQueryRangeState(RTVFS hVfs, uint64_t off, size_t cb, bool *pfUsed);
+
+
+/** @defgroup grp_vfs_obj VFS Base Object API
+ * @{
+ */
+
+/**
+ * Retains a reference to the VFS base object handle.
+ *
+ * @returns New reference count on success, UINT32_MAX on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(uint32_t) RTVfsObjRetain(RTVFSOBJ hVfsObj);
+RTDECL(uint32_t) RTVfsObjRetainDebug(RTVFSOBJ hVfsObj, RT_SRC_POS_DECL);
+
+/**
+ * Releases a reference to the VFS base handle.
+ *
+ * @returns New reference count on success (0 if closed), UINT32_MAX on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(uint32_t) RTVfsObjRelease(RTVFSOBJ hVfsObj);
+
+/** @name RTVFSOBJ_F_XXX - Flags or RTVfsObjOpen and RTVfsDirOpenObj.
+ * @note Must leave space for RTPATH_F_XXX.
+ * @{ */
+/** Directory (RTFS_TYPE_DIRECTORY). */
+#define RTVFSOBJ_F_OPEN_DIRECTORY RT_BIT_32(8)
+/** Symbolic link (RTFS_TYPE_SYMLINK). */
+#define RTVFSOBJ_F_OPEN_SYMLINK RT_BIT_32(9)
+/** Regular file (RTFS_TYPE_FILE). */
+#define RTVFSOBJ_F_OPEN_FILE RT_BIT_32(10)
+/** Character device (RTFS_TYPE_DEV_CHAR). */
+#define RTVFSOBJ_F_OPEN_DEV_CHAR RT_BIT_32(11)
+/** Block device (RTFS_TYPE_DEV_BLOCK). */
+#define RTVFSOBJ_F_OPEN_DEV_BLOCK RT_BIT_32(12)
+/** Named pipe (fifo) (RTFS_TYPE_FIFO). */
+#define RTVFSOBJ_F_OPEN_FIFO RT_BIT_32(13)
+/** Socket (RTFS_TYPE_SOCKET). */
+#define RTVFSOBJ_F_OPEN_SOCKET RT_BIT_32(14)
+/** Mounted VFS. */
+#define RTVFSOBJ_F_OPEN_MOUNT RT_BIT_32(15)
+/** Mask object types we wish to open. */
+#define RTVFSOBJ_F_OPEN_MASK UINT32_C(0x0000ff00)
+/** Any kind of object that translates to RTVFSOBJTYPE_FILE. */
+#define RTVFSOBJ_F_OPEN_ANY_FILE (RTVFSOBJ_F_OPEN_FILE | RTVFSOBJ_F_OPEN_DEV_BLOCK)
+/** Any kind of object that translates to RTVFSOBJTYPE_IOS or
+ * RTVFSOBJTYPE_FILE. */
+#define RTVFSOBJ_F_OPEN_ANY_IO_STREAM ( RTVFSOBJ_F_ANY_OPEN_FILE | RTVFSOBJ_F_DEV_OPEN_BLOCK \
+ | RTVFSOBJ_F_OPEN_FIFO | RTVFSOBJ_F_OPEN_SOCKET)
+/** Any kind of object. */
+#define RTVFSOBJ_F_OPEN_ANY RTVFSOBJ_F_OPEN_MASK
+
+/** Do't create anything, return file not found. */
+#define RTVFSOBJ_F_CREATE_NOTHING UINT32_C(0x00000000)
+/** Create a file if the if the object was not found and the RTFILE_O_XXX
+ * flags allows it. */
+#define RTVFSOBJ_F_CREATE_FILE UINT32_C(0x00010000)
+/** Create a directory if the object was not found and the RTFILE_O_XXX
+ * flags allows it. */
+#define RTVFSOBJ_F_CREATE_DIRECTORY UINT32_C(0x00020000)
+/** The creation type mask. */
+#define RTVFSOBJ_F_CREATE_MASK UINT32_C(0x00070000)
+
+/** Indicate that this call is for traversal.
+ * @internal only */
+#define RTVFSOBJ_F_TRAVERSAL RT_BIT_32(31)
+/** Valid mask for external callers. */
+#define RTVFSOBJ_F_VALID_MASK UINT32_C(0x0007ff00)
+/** @} */
+
+/**
+ * Opens any file system object in the given VFS.
+ *
+ * @returns IPRT status code.
+ * @param hVfs The VFS to open the object within.
+ * @param pszPath Path to the file.
+ * @param fFileOpen RTFILE_O_XXX flags.
+ * @param fObjFlags More flags: RTVFSOBJ_F_XXX, RTPATH_F_XXX.
+ * @param phVfsObj Where to return the object handle.
+ * @sa RTVfsDirOpenObj, RTVfsDirOpenDir, RTVfsDirOpenFile
+ */
+RTDECL(int) RTVfsObjOpen(RTVFS hVfs, const char *pszPath, uint64_t fFileOpen, uint32_t fObjFlags, PRTVFSOBJ phVfsObj);
+
+/**
+ * Query information about the object.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_NOT_SUPPORTED if the @a enmAddAttr value is not handled by the
+ * implementation.
+ *
+ * @param hVfsObj The VFS object handle.
+ * @param pObjInfo Where to return the info.
+ * @param enmAddAttr Which additional attributes should be retrieved.
+ * @sa RTVfsIoStrmQueryInfo, RTVfsFileQueryInfo, RTFileQueryInfo,
+ * RTPathQueryInfo
+ */
+RTDECL(int) RTVfsObjQueryInfo(RTVFSOBJ hVfsObj, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr);
+
+/**
+ * Sets the file mode for the given VFS object.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_INVALID_FUNCTION if the object type has no file mode to set.
+ * Only directories, files and symbolic links support this operation.
+ *
+ * @param hVfsObj The VFS object handle.
+ * @param fMode The mode mask.
+ * @param fMask The bits in the mode mask which should be changed.
+ */
+RTDECL(int) RTVfsObjSetMode(RTVFSOBJ hVfsObj, RTFMODE fMode, RTFMODE fMask);
+
+/**
+ * Sets one or more timestamps for the given VFS object.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_INVALID_FUNCTION if the object type has no file mode to set.
+ * Only directories, files and symbolic links support this operation.
+ *
+ * @param hVfsObj The VFS object handle.
+ * @param pAccessTime Pointer to the new access time. NULL if not to
+ * be changed.
+ * @param pModificationTime Pointer to the new modifcation time. NULL if not
+ * to be changed.
+ * @param pChangeTime Pointer to the new change time. NULL if not to
+ * be changed.
+ * @param pBirthTime Pointer to the new time of birth. NULL if not to
+ * be changed.
+ *
+ * @remarks See RTFileSetTimes for restrictions and behavior imposed by the
+ * host OS or underlying VFS provider.
+ * @sa RTFileSetTimes, RTPathSetTimes
+ */
+RTDECL(int) RTVfsObjSetTimes(RTVFSOBJ hVfsObj, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+ PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime);
+
+/**
+ * Set the unix style owner and group on the given VFS object.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_INVALID_FUNCTION if the object type has no file mode to set.
+ * Only directories, files and symbolic links support this operation.
+ *
+ * @param hVfsObj The VFS object handle.
+ * @param uid The user ID of the new owner. NIL_RTUID if
+ * unchanged.
+ * @param gid The group ID of the new owner group. NIL_RTGID if
+ * unchanged.
+ *
+ * @sa RTFileSetOwner, RTPathSetOwner.
+ */
+RTDECL(int) RTVfsObjSetOwner(RTVFSOBJ hVfsObj, RTUID uid, RTGID gid);
+
+
+/**
+ * Gets the type of a VFS object.
+ *
+ * @returns The VFS object type on success, RTVFSOBJTYPE_INVALID on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(RTVFSOBJTYPE) RTVfsObjGetType(RTVFSOBJ hVfsObj);
+
+/**
+ * Converts a VFS base object handle to a VFS handle.
+ *
+ * @returns Referenced handle on success, NIL on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(RTVFS) RTVfsObjToVfs(RTVFSOBJ hVfsObj);
+
+/**
+ * Converts a VFS base object handle to a VFS filesystem stream handle.
+ *
+ * @returns Referenced handle on success, NIL on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(RTVFSFSSTREAM) RTVfsObjToFsStream(RTVFSOBJ hVfsObj);
+
+/**
+ * Converts a VFS base object handle to a VFS directory handle.
+ *
+ * @returns Referenced handle on success, NIL on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(RTVFSDIR) RTVfsObjToDir(RTVFSOBJ hVfsObj);
+
+/**
+ * Converts a VFS base object handle to a VFS I/O stream handle.
+ *
+ * @returns Referenced handle on success, NIL on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(RTVFSIOSTREAM) RTVfsObjToIoStream(RTVFSOBJ hVfsObj);
+
+/**
+ * Converts a VFS base object handle to a VFS file handle.
+ *
+ * @returns Referenced handle on success, NIL on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(RTVFSFILE) RTVfsObjToFile(RTVFSOBJ hVfsObj);
+
+/**
+ * Converts a VFS base object handle to a VFS symbolic link handle.
+ *
+ * @returns Referenced handle on success, NIL on failure.
+ * @param hVfsObj The VFS base object handle.
+ */
+RTDECL(RTVFSSYMLINK) RTVfsObjToSymlink(RTVFSOBJ hVfsObj);
+
+
+/**
+ * Converts a VFS handle to a VFS base object handle.
+ *
+ * @returns Referenced handle on success, NIL if the input handle was invalid.
+ * @param hVfs The VFS handle.
+ */
+RTDECL(RTVFSOBJ) RTVfsObjFromVfs(RTVFS hVfs);
+
+/**
+ * Converts a VFS filesystem stream handle to a VFS base object handle.
+ *
+ * @returns Referenced handle on success, NIL if the input handle was invalid.
+ * @param hVfsFss The VFS filesystem stream handle.
+ */
+RTDECL(RTVFSOBJ) RTVfsObjFromFsStream(RTVFSFSSTREAM hVfsFss);
+
+/**
+ * Converts a VFS directory handle to a VFS base object handle.
+ *
+ * @returns Referenced handle on success, NIL if the input handle was invalid.
+ * @param hVfsDir The VFS directory handle.
+ */
+RTDECL(RTVFSOBJ) RTVfsObjFromDir(RTVFSDIR hVfsDir);
+
+/**
+ * Converts a VFS I/O stream handle to a VFS base object handle.
+ *
+ * @returns Referenced handle on success, NIL if the input handle was invalid.
+ * @param hVfsIos The VFS I/O stream handle.
+ */
+RTDECL(RTVFSOBJ) RTVfsObjFromIoStream(RTVFSIOSTREAM hVfsIos);
+
+/**
+ * Converts a VFS file handle to a VFS base object handle.
+ *
+ * @returns Referenced handle on success, NIL if the input handle was invalid.
+ * @param hVfsFile The VFS file handle.
+ */
+RTDECL(RTVFSOBJ) RTVfsObjFromFile(RTVFSFILE hVfsFile);
+
+/**
+ * Converts a VFS symbolic link handle to a VFS base object handle.
+ *
+ * @returns Referenced handle on success, NIL if the input handle was invalid.
+ * @param hVfsSym The VFS symbolic link handle.
+ */
+RTDECL(RTVFSOBJ) RTVfsObjFromSymlink(RTVFSSYMLINK hVfsSym);
+
+/** @} */
+
+
+/** @defgroup grp_vfs_fsstream VFS Filesystem Stream API
+ *
+ * Filesystem streams are for tar, cpio and similar. Any virtual filesystem can
+ * be turned into a filesystem stream using RTVfsFsStrmFromVfs.
+ *
+ * @{
+ */
+
+RTDECL(uint32_t) RTVfsFsStrmRetain(RTVFSFSSTREAM hVfsFss);
+RTDECL(uint32_t) RTVfsFsStrmRetainDebug(RTVFSFSSTREAM hVfsFss, RT_SRC_POS_DECL);
+RTDECL(uint32_t) RTVfsFsStrmRelease(RTVFSFSSTREAM hVfsFss);
+RTDECL(int) RTVfsFsStrmQueryInfo(RTVFSFSSTREAM hVfsFss, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr);
+
+/**
+ * Gets the next object in the stream.
+ *
+ * This call may affect the stream posision of a previously returned object.
+ *
+ * The type of object returned here typically boils down to three types:
+ * - I/O streams (representing files),
+ * - symbolic links
+ * - base object
+ * The base objects represent anything not convered by the two other, i.e.
+ * directories, device nodes, fifos, sockets and whatnot. The details can be
+ * queried using RTVfsObjQueryInfo.
+ *
+ * That said, absolutely any object except for filesystem stream objects can be
+ * returned by this call. Any generic code is adviced to just deal with it all.
+ *
+ * @returns IPRT status code.
+ * @retval VINF_SUCCESS if a new object was retrieved.
+ * @retval VERR_EOF when there are no more objects.
+ * @retval VERR_INVALID_FUNCTION if called on a non-readable stream.
+ *
+ * @param hVfsFss The file system stream handle.
+ * @param ppszName Where to return the object name. Must be freed by
+ * calling RTStrFree.
+ * @param penmType Where to return the object type.
+ * @param phVfsObj Where to return the object handle (referenced). This
+ * must be cast to the desired type before use.
+ */
+RTDECL(int) RTVfsFsStrmNext(RTVFSFSSTREAM hVfsFss, char **ppszName, RTVFSOBJTYPE *penmType, PRTVFSOBJ phVfsObj);
+
+/**
+ * Appends a VFS object to the stream.
+ *
+ * The stream must be writable.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_INVALID_FUNCTION if called on a non-writable stream.
+ * @param hVfsFss The file system stream handle.
+ * @param pszPath The path.
+ * @param hVfsObj The VFS object to add.
+ * @param fFlags RTVFSFSSTRM_ADD_F_XXX.
+ */
+RTDECL(int) RTVfsFsStrmAdd(RTVFSFSSTREAM hVfsFss, const char *pszPath, RTVFSOBJ hVfsObj, uint32_t fFlags);
+
+/** @name RTVFSFSSTRM_ADD_F_XXX - Flags for RTVfsFsStrmAdd.
+ * @{ */
+/** Input is an I/O stream of indeterminate length, read to the end and then
+ * update the file header.
+ * @note This is *only* possible if the output stream is actually a file. */
+#define RTVFSFSSTRM_ADD_F_STREAM RT_BIT_32(0)
+/** Mask of flags specific to the target stream. */
+#define RTVFSFSSTRM_ADD_F_SPECIFIC_MASK UINT32_C(0xff000000)
+/** Valid bits. */
+#define RTVFSFSSTRM_ADD_F_VALID_MASK UINT32_C(0xff000001)
+/** @} */
+
+/**
+ * Pushes an byte stream onto the stream.
+ *
+ * The stream must be writable.
+ *
+ * This differs from RTVfsFsStrmAdd() in that it will create a regular file in
+ * the output file system stream and provide the actual content bytes via the
+ * returned I/O stream object.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_INVALID_FUNCTION if called on a non-writable stream.
+ * @param hVfsFss The file system stream handle.
+ * @param pszPath The path to the file.
+ * @param cbFile The file size. This can also be set to UINT64_MAX if
+ * the file system stream is backed by a file.
+ * @param paObjInfo Array of zero or more RTFSOBJINFO structures containing
+ * different pieces of information about the file. If any
+ * provided, the first one should be a RTFSOBJATTRADD_UNIX
+ * one, additional can be supplied if wanted. What exactly
+ * is needed depends on the underlying FS stream
+ * implementation.
+ * @param cObjInfo Number of items in the array @a paObjInfo points at.
+ * @param fFlags RTVFSFSSTRM_PUSH_F_XXX.
+ * @param phVfsIos Where to return the I/O stream to feed the file content
+ * to. If the FS stream is backed by a file, the returned
+ * handle can be cast to a file if necessary.
+ */
+RTDECL(int) RTVfsFsStrmPushFile(RTVFSFSSTREAM hVfsFss, const char *pszPath, uint64_t cbFile,
+ PCRTFSOBJINFO paObjInfo, uint32_t cObjInfo, uint32_t fFlags, PRTVFSIOSTREAM phVfsIos);
+
+/** @name RTVFSFSSTRM_PUSH_F_XXX - Flags for RTVfsFsStrmPushFile.
+ * @{ */
+/** Input is an I/O stream of indeterminate length, read to the end and then
+ * update the file header.
+ * @note This is *only* possible if the output stream is actually a file. */
+#define RTVFSFSSTRM_PUSH_F_STREAM RT_BIT_32(0)
+/** Mask of flags specific to the target stream. */
+#define RTVFSFSSTRM_PUSH_F_SPECIFIC_MASK UINT32_C(0xff000000)
+/** Valid bits. */
+#define RTVFSFSSTRM_PUSH_F_VALID_MASK UINT32_C(0xff000001)
+/** @} */
+
+/**
+ * Marks the end of the stream.
+ *
+ * The stream must be writable.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_INVALID_FUNCTION if called on a non-writable stream.
+ * @param hVfsFss The file system stream handle.
+ */
+RTDECL(int) RTVfsFsStrmEnd(RTVFSFSSTREAM hVfsFss);
+
+/** @} */
+
+
+/** @defgroup grp_vfs_dir VFS Directory API
+ * @{
+ */
+
+/**
+ * Retains a reference to the VFS directory handle.
+ *
+ * @returns New reference count on success, UINT32_MAX on failure.
+ * @param hVfsDir The VFS directory handle.
+ */
+RTDECL(uint32_t) RTVfsDirRetain(RTVFSDIR hVfsDir);
+RTDECL(uint32_t) RTVfsDirRetainDebug(RTVFSDIR hVfsDir, RT_SRC_POS_DECL);
+
+/**
+ * Releases a reference to the VFS directory handle.
+ *
+ * @returns New reference count on success (0 if closed), UINT32_MAX on failure.
+ * @param hVfsDir The VFS directory handle.
+ */
+RTDECL(uint32_t) RTVfsDirRelease(RTVFSDIR hVfsDir);
+
+/**
+ * Opens a directory in the specified file system.
+ *
+ * @returns IPRT status code.
+ * @param hVfs The VFS to open the directory within.
+ * @param pszPath Path to the directory, relative to the root.
+ * @param fFlags Reserved, MBZ.
+ * @param phVfsDir Where to return the directory.
+ */
+RTDECL(int) RTVfsDirOpen(RTVFS hVfs, const char *pszPath, uint32_t fFlags, PRTVFSDIR phVfsDir);
+
+/**
+ * Opens any file system object in or under the given directory.
+ *
+ * @returns IPRT status code.
+ * @param hVfsDir The VFS directory start walking the @a pszPath
+ * relative to.
+ * @param pszPath Path to the file.
+ * @param fFileOpen RTFILE_O_XXX flags.
+ * @param fObjFlags More flags: RTVFSOBJ_F_XXX, RTPATH_F_XXX.
+ * @param phVfsObj Where to return the object handle.
+ * @sa RTVfsObjOpen, RTVfsDirOpenDir, RTVfsDirOpenFile
+ */
+RTDECL(int) RTVfsDirOpenObj(RTVFSDIR hVfsDir, const char *pszPath, uint64_t fFileOpen, uint32_t fObjFlags, PRTVFSOBJ phVfsObj);
+
+/**
+ * Opens a file in or under the given directory.
+ *
+ * @returns IPRT status code.
+ * @param hVfsDir The VFS directory start walking the @a pszPath
+ * relative to.
+ * @param pszPath Path to the file.
+ * @param fOpen RTFILE_O_XXX flags.
+ * @param phVfsFile Where to return the file.
+ * @sa RTVfsDirOpenFileAsIoStream
+ */
+RTDECL(int) RTVfsDirOpenFile(RTVFSDIR hVfsDir, const char *pszPath, uint64_t fOpen, PRTVFSFILE phVfsFile);
+
+/**
+ * Convenience wrapper around RTVfsDirOpenFile that returns an I/O stream.
+ *
+ * @returns IPRT status code.
+ * @param hVfsDir The VFS directory start walking the @a pszPath
+ * relative to.
+ * @param pszPath Path to the file.
+ * @param fOpen RTFILE_O_XXX flags.
+ * @param phVfsIos Where to return the I/O stream handle of the file.
+ * @sa RTVfsDirOpenFile
+ */
+RTDECL(int) RTVfsDirOpenFileAsIoStream(RTVFSDIR hVfsDir, const char *pszPath, uint64_t fOpen, PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Opens a directory in or under the given directory.
+ *
+ * @returns IPRT status code.
+ * @param hVfsDir The VFS directory start walking the @a pszPath
+ * relative to.
+ * @param pszPath Path to the file.
+ * @param fFlags Reserved, MBZ.
+ * @param phVfsDir Where to return the directory.
+ */
+RTDECL(int) RTVfsDirOpenDir(RTVFSDIR hVfsDir, const char *pszPath, uint32_t fFlags, PRTVFSDIR phVfsDir);
+
+/**
+ * Creates a directory relative to @a hVfsDir.
+ *
+ * @returns IPRT status code
+ * @param hVfsDir The directory the path is relative to.
+ * @param pszRelPath The relative path to the new directory.
+ * @param fMode The file mode for the new directory.
+ * @param fFlags Directory creation flags, RTDIRCREATE_FLAGS_XXX.
+ * @param phVfsDir Where to return the handle to the newly created
+ * directory. Optional.
+ * @sa RTDirCreate, RTDirRelDirCreate
+ */
+RTDECL(int) RTVfsDirCreateDir(RTVFSDIR hVfsDir, const char *pszRelPath, RTFMODE fMode, uint32_t fFlags, PRTVFSDIR phVfsDir);
+
+/**
+ * Create a VFS directory handle from a standard IPRT directory handle (RTDIR).
+ *
+ * @returns IPRT status code.
+ * @param hDir The standard IPRT directory handle.
+ * @param fLeaveOpen Whether to leave the handle open when the VFS
+ * directory is released, or to close it (@c false).
+ * @param phVfsDir Where to return the VFS directory handle.
+ */
+RTDECL(int) RTVfsDirFromRTDir(RTDIR hDir, bool fLeaveOpen, PRTVFSDIR phVfsDir);
+
+/**
+ * RTDirOpen + RTVfsDirFromRTDir.
+ *
+ * @returns IPRT status code.
+ * @param pszPath The path to the directory.
+ * @param fFlags RTDIR_F_XXX.
+ * @param phVfsDir Where to return the VFS directory handle.
+ */
+RTDECL(int) RTVfsDirOpenNormal(const char *pszPath, uint32_t fFlags, PRTVFSDIR phVfsDir);
+
+/**
+ * Queries information about a object in or under the given directory.
+ *
+ * @returns IPRT Status code.
+ * @param hVfsDir The VFS directory start walking the @a pszPath
+ * relative to.
+ * @param pszPath Path to the object.
+ * @param pObjInfo Where to return info.
+ * @param enmAddAttr What to return.
+ * @param fFlags RTPATH_F_XXX.
+ * @sa RTPathQueryInfoEx, RTVfsQueryPathInfo, RTVfsObjQueryInfo
+ */
+RTDECL(int) RTVfsDirQueryPathInfo(RTVFSDIR hVfsDir, const char *pszPath, PRTFSOBJINFO pObjInfo,
+ RTFSOBJATTRADD enmAddAttr, uint32_t fFlags);
+
+/**
+ * Removes a directory relative to @a hVfsDir.
+ *
+ * @returns IPRT status code.
+ * @param hVfsDir The VFS directory to start walking the @a pszRelPath
+ * relative to.
+ * @param pszRelPath The path to the directory that should be removed.
+ * @param fFlags Reserved, MBZ.
+ */
+RTDECL(int) RTVfsDirRemoveDir(RTVFSDIR hVfsDir, const char *pszRelPath, uint32_t fFlags);
+
+/**
+ * Reads the next entry in the directory returning extended information.
+ *
+ * @returns VINF_SUCCESS and data in pDirEntry on success.
+ * @returns VERR_NO_MORE_FILES when the end of the directory has been reached.
+ * @returns VERR_BUFFER_OVERFLOW if the buffer is too small to contain the filename. If
+ * pcbDirEntry is specified it will be updated with the required buffer size.
+ * @returns suitable iprt status code on other errors.
+ *
+ * @param hVfsDir The VFS directory.
+ * @param pDirEntry Where to store the information about the next
+ * directory entry on success.
+ * @param pcbDirEntry Optional parameter used for variable buffer size.
+ *
+ * On input the variable pointed to contains the size of the pDirEntry
+ * structure. This must be at least OFFSET(RTDIRENTRYEX, szName[2]) bytes.
+ *
+ * On successful output the field is updated to
+ * OFFSET(RTDIRENTRYEX, szName[pDirEntry->cbName + 1]).
+ *
+ * When the data doesn't fit in the buffer and VERR_BUFFER_OVERFLOW is
+ * returned, this field contains the required buffer size.
+ *
+ * The value is unchanged in all other cases.
+ * @param enmAddAttr Which set of additional attributes to request.
+ * Use RTFSOBJATTRADD_NOTHING if this doesn't matter.
+ *
+ * @sa RTDirReadEx
+ */
+RTDECL(int) RTVfsDirReadEx(RTVFSDIR hVfsDir, PRTDIRENTRYEX pDirEntry, size_t *pcbDirEntry, RTFSOBJATTRADD enmAddAttr);
+
+/** @} */
+
+
+/** @defgroup grp_vfs_symlink VFS Symbolic Link API
+ *
+ * @remarks The TAR VFS and filesystem stream uses symbolic links for
+ * describing hard links as well. The users must use RTFS_IS_SYMLINK
+ * to check if it is a real symlink in those cases.
+ *
+ * @remarks Any VFS which is backed by a real file system may be subject to
+ * races with other processes or threads, so the user may get
+ * unexpected errors when this happends. This is a bit host specific,
+ * i.e. it might be prevent on windows if we care.
+ *
+ * @{
+ */
+
+
+/**
+ * Retains a reference to the VFS symbolic link handle.
+ *
+ * @returns New reference count on success, UINT32_MAX on failure.
+ * @param hVfsSym The VFS symbolic link handle.
+ */
+RTDECL(uint32_t) RTVfsSymlinkRetain(RTVFSSYMLINK hVfsSym);
+RTDECL(uint32_t) RTVfsSymlinkRetainDebug(RTVFSSYMLINK hVfsSym, RT_SRC_POS_DECL);
+
+/**
+ * Releases a reference to the VFS symbolic link handle.
+ *
+ * @returns New reference count on success (0 if closed), UINT32_MAX on failure.
+ * @param hVfsSym The VFS symbolic link handle.
+ */
+RTDECL(uint32_t) RTVfsSymlinkRelease(RTVFSSYMLINK hVfsSym);
+
+/**
+ * Query information about the symbolic link.
+ *
+ * @returns IPRT status code.
+ * @param hVfsSym The VFS symbolic link handle.
+ * @param pObjInfo Where to return the info.
+ * @param enmAddAttr Which additional attributes should be retrieved.
+ *
+ * @sa RTFileQueryInfo, RTPathQueryInfo, RTPathQueryInfoEx
+ */
+RTDECL(int) RTVfsSymlinkQueryInfo(RTVFSSYMLINK hVfsSym, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr);
+
+/**
+ * Set the unix style owner and group.
+ *
+ * @returns IPRT status code.
+ * @param hVfsSym The VFS symbolic link handle.
+ * @param fMode The new mode bits.
+ * @param fMask The mask indicating which bits we are changing.
+ * @sa RTFileSetMode, RTPathSetMode
+ */
+RTDECL(int) RTVfsSymlinkSetMode(RTVFSSYMLINK hVfsSym, RTFMODE fMode, RTFMODE fMask);
+
+/**
+ * Set the timestamps associated with the object.
+ *
+ * @returns IPRT status code.
+ * @param hVfsSym The VFS symbolic link handle.
+ * @param pAccessTime Pointer to the new access time. NULL if not
+ * to be changed.
+ * @param pModificationTime Pointer to the new modifcation time. NULL if
+ * not to be changed.
+ * @param pChangeTime Pointer to the new change time. NULL if not to be
+ * changed.
+ * @param pBirthTime Pointer to the new time of birth. NULL if not to be
+ * changed.
+ * @remarks See RTFileSetTimes for restrictions and behavior imposed by the
+ * host OS or underlying VFS provider.
+ * @sa RTFileSetTimes, RTPathSetTimes
+ */
+RTDECL(int) RTVfsSymlinkSetTimes(RTVFSSYMLINK hVfsSym, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
+ PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime);
+
+/**
+ * Set the unix style owner and group.
+ *
+ * @returns IPRT status code.
+ * @param hVfsSym The VFS symbolic link handle.
+ * @param uid The user ID of the new owner. NIL_RTUID if
+ * unchanged.
+ * @param gid The group ID of the new owner group. NIL_RTGID if
+ * unchanged.
+ * @sa RTFileSetOwner, RTPathSetOwner.
+ */
+RTDECL(int) RTVfsSymlinkSetOwner(RTVFSSYMLINK hVfsSym, RTUID uid, RTGID gid);
+
+/**
+ * Read the symbolic link target.
+ *
+ * @returns IPRT status code.
+ * @param hVfsSym The VFS symbolic link handle.
+ * @param pszTarget The target buffer.
+ * @param cbTarget The size of the target buffer.
+ * @sa RTSymlinkRead
+ */
+RTDECL(int) RTVfsSymlinkRead(RTVFSSYMLINK hVfsSym, char *pszTarget, size_t cbTarget);
+
+/** @} */
+
+
+
+/** @defgroup grp_vfs_iostream VFS I/O Stream API
+ * @{
+ */
+
+/**
+ * Creates a VFS file from a memory buffer.
+ *
+ * @returns IPRT status code.
+ *
+ * @param fFlags A combination of RTFILE_O_READ and RTFILE_O_WRITE.
+ * @param pvBuf The buffer. This will be copied and not referenced
+ * after this function returns.
+ * @param cbBuf The buffer size.
+ * @param phVfsIos Where to return the VFS I/O stream handle.
+ */
+RTDECL(int) RTVfsIoStrmFromBuffer(uint32_t fFlags, void const *pvBuf, size_t cbBuf, PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Creates a VFS I/O stream handle from a standard IPRT file handle (RTFILE).
+ *
+ * @returns IPRT status code.
+ * @param hFile The standard IPRT file handle.
+ * @param fOpen The flags the handle was opened with. Pass 0 to
+ * have these detected.
+ * @param fLeaveOpen Whether to leave the handle open when the VFS file
+ * is released, or to close it (@c false).
+ * @param phVfsIos Where to return the VFS I/O stream handle.
+ */
+RTDECL(int) RTVfsIoStrmFromRTFile(RTFILE hFile, uint64_t fOpen, bool fLeaveOpen, PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Creates a VFS I/O stream handle from a standard IPRT pipe handle (RTPIPE).
+ *
+ * @returns IPRT status code.
+ * @param hPipe The standard IPRT pipe handle.
+ * @param fLeaveOpen Whether to leave the handle open when the VFS file
+ * is released, or to close it (@c false).
+ * @param phVfsIos Where to return the VFS I/O stream handle.
+ */
+RTDECL(int) RTVfsIoStrmFromRTPipe(RTPIPE hPipe, bool fLeaveOpen, PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Convenience function combining RTFileOpen with RTVfsIoStrmFromRTFile.
+ *
+ * @returns IPRT status code.
+ * @param pszFilename The path to the file in the normal file system.
+ * @param fOpen The flags to pass to RTFileOpen when opening the
+ * file, i.e. RTFILE_O_XXX.
+ * @param phVfsIos Where to return the VFS I/O stream handle.
+ */
+RTDECL(int) RTVfsIoStrmOpenNormal(const char *pszFilename, uint64_t fOpen, PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Create a VFS I/O stream handle from one of the standard handles.
+ *
+ * @returns IPRT status code.
+ * @param enmStdHandle The standard IPRT file handle.
+ * @param fOpen The flags the handle was opened with. Pass 0 to
+ * have these detected.
+ * @param fLeaveOpen Whether to leave the handle open when the VFS file
+ * is released, or to close it (@c false).
+ * @param phVfsIos Where to return the VFS I/O stream handle.
+ */
+RTDECL(int) RTVfsIoStrmFromStdHandle(RTHANDLESTD enmStdHandle, uint64_t fOpen, bool fLeaveOpen,
+ PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Retains a reference to the VFS I/O stream handle.
+ *
+ * @returns New reference count on success, UINT32_MAX on failure.
+ * @param hVfsIos The VFS I/O stream handle.
+ */
+RTDECL(uint32_t) RTVfsIoStrmRetain(RTVFSIOSTREAM hVfsIos);
+RTDECL(uint32_t) RTVfsIoStrmRetainDebug(RTVFSIOSTREAM hVfsIos, RT_SRC_POS_DECL);
+
+/**
+ * Releases a reference to the VFS I/O stream handle.
+ *
+ * @returns New reference count on success (0 if closed), UINT32_MAX on failure.
+ * @param hVfsIos The VFS I/O stream handle.
+ */
+RTDECL(uint32_t) RTVfsIoStrmRelease(RTVFSIOSTREAM hVfsIos);
+
+/**
+ * Convert the VFS I/O stream handle to a VFS file handle.
+ *
+ * @returns The VFS file handle on success, this must be released.
+ * NIL_RTVFSFILE if the I/O stream handle is invalid.
+ * @param hVfsIos The VFS I/O stream handle.
+ * @sa RTVfsFileToIoStream
+ */
+RTDECL(RTVFSFILE) RTVfsIoStrmToFile(RTVFSIOSTREAM hVfsIos);
+
+/**
+ * Query information about the I/O stream.
+ *
+ * @returns IPRT status code.
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param pObjInfo Where to return the info.
+ * @param enmAddAttr Which additional attributes should be retrieved.
+ * @sa RTFileQueryInfo
+ */
+RTDECL(int) RTVfsIoStrmQueryInfo(RTVFSIOSTREAM hVfsIos, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr);
+
+/**
+ * Read bytes from the I/O stream.
+ *
+ * @returns IPRT status code.
+ * @retval VINF_SUCCESS and the number of bytes read written to @a pcbRead.
+ * @retval VINF_TRY_AGAIN if @a fBlocking is @c false, @a pcbRead is not NULL,
+ * and no data was available. @a *pcbRead will be set to 0.
+ * @retval VINF_EOF when trying to read __beyond__ the end of the stream and
+ * @a pcbRead is not NULL (it will be set to the number of bytes read,
+ * or 0 if the end of the stream was reached before this call).
+ * When the last byte of the read request is the last byte in the
+ * stream, this status code will not be used. However, VINF_EOF is
+ * returned when attempting to read 0 bytes while standing at the end
+ * of the stream.
+ * @retval VERR_EOF when trying to read __beyond__ the end of the stream and
+ * @a pcbRead is NULL.
+ * @retval VERR_ACCESS_DENIED if the stream is not readable.
+ *
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param pvBuf Where to store the read bytes.
+ * @param cbToRead The number of bytes to read.
+ * @param fBlocking Whether the call is blocking (@c true) or not. If
+ * not, the @a pcbRead parameter must not be NULL.
+ * @param pcbRead Where to always store the number of bytes actually
+ * read. This can be NULL if @a fBlocking is true.
+ * @sa RTVfsFileRead, RTFileRead, RTPipeRead, RTPipeReadBlocking,
+ * RTSocketRead
+ */
+RTDECL(int) RTVfsIoStrmRead(RTVFSIOSTREAM hVfsIos, void *pvBuf, size_t cbToRead, bool fBlocking, size_t *pcbRead);
+
+/**
+ * Read bytes from the I/O stream, optionally with offset.
+ *
+ * @returns IPRT status code.
+ * @retval VINF_SUCCESS and the number of bytes read written to @a pcbRead.
+ * @retval VINF_TRY_AGAIN if @a fBlocking is @c false, @a pcbRead is not NULL,
+ * and no data was available. @a *pcbRead will be set to 0.
+ * @retval VINF_EOF when trying to read __beyond__ the end of the stream and
+ * @a pcbRead is not NULL (it will be set to the number of bytes read,
+ * or 0 if the end of the stream was reached before this call).
+ * When the last byte of the read request is the last byte in the
+ * stream, this status code will not be used. However, VINF_EOF is
+ * returned when attempting to read 0 bytes while standing at the end
+ * of the stream.
+ * @retval VERR_EOF when trying to read __beyond__ the end of the stream and
+ * @a pcbRead is NULL.
+ * @retval VERR_ACCESS_DENIED if the stream is not readable.
+ *
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param off Where to read at, -1 for the current position.
+ * @param pvBuf Where to store the read bytes.
+ * @param cbToRead The number of bytes to read.
+ * @param fBlocking Whether the call is blocking (@c true) or not. If
+ * not, the @a pcbRead parameter must not be NULL.
+ * @param pcbRead Where to always store the number of bytes actually
+ * read. This can be NULL if @a fBlocking is true.
+ * @sa RTVfsFileRead, RTFileRead, RTPipeRead, RTPipeReadBlocking,
+ * RTSocketRead
+ */
+RTDECL(int) RTVfsIoStrmReadAt(RTVFSIOSTREAM hVfsIos, RTFOFF off, void *pvBuf, size_t cbToRead, bool fBlocking, size_t *pcbRead);
+
+/**
+ * Reads the remainder of the stream into a memory buffer.
+ *
+ * For simplifying string-style processing, the is a zero byte after the
+ * returned buffer, making sure it can be used as a zero terminated string.
+ *
+ * @returns IPRT status code.
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param ppvBuf Where to return the buffer. Must pass to
+ * RTVfsIoStrmReadAllFree for freeing, not RTMemFree!
+ * @param pcbBuf Where to return the buffer size.
+ */
+RTDECL(int) RTVfsIoStrmReadAll(RTVFSIOSTREAM hVfsIos, void **ppvBuf, size_t *pcbBuf);
+
+/**
+ * Free memory buffer returned by RTVfsIoStrmReadAll.
+ *
+ * @param pvBuf What RTVfsIoStrmReadAll returned.
+ * @param cbBuf What RTVfsIoStrmReadAll returned.
+ */
+RTDECL(void) RTVfsIoStrmReadAllFree(void *pvBuf, size_t cbBuf);
+
+/**
+ * Write bytes to the I/O stream.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_ACCESS_DENIED if the stream is not writable.
+ *
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param pvBuf The bytes to write.
+ * @param cbToWrite The number of bytes to write.
+ * @param fBlocking Whether the call is blocking (@c true) or not. If
+ * not, the @a pcbWritten parameter must not be NULL.
+ * @param pcbWritten Where to always store the number of bytes actually
+ * written. This can be NULL if @a fBlocking is true.
+ * @sa RTVfsFileWrite, RTFileWrite, RTPipeWrite, RTPipeWriteBlocking,
+ * RTSocketWrite
+ */
+RTDECL(int) RTVfsIoStrmWrite(RTVFSIOSTREAM hVfsIos, const void *pvBuf, size_t cbToWrite, bool fBlocking, size_t *pcbWritten);
+RTDECL(int) RTVfsIoStrmWriteAt(RTVFSIOSTREAM hVfsIos, RTFOFF off, const void *pvBuf, size_t cbToWrite, bool fBlocking, size_t *pcbWritten);
+
+/**
+ * Reads bytes from the I/O stream into a scatter buffer.
+ *
+ * @returns IPRT status code.
+ * @retval VINF_SUCCESS and the number of bytes read written to @a pcbRead.
+ * @retval VINF_TRY_AGAIN if @a fBlocking is @c false, @a pcbRead is not NULL,
+ * and no data was available. @a *pcbRead will be set to 0.
+ * @retval VINF_EOF when trying to read __beyond__ the end of the stream and
+ * @a pcbRead is not NULL (it will be set to the number of bytes read,
+ * or 0 if the end of the stream was reached before this call).
+ * When the last byte of the read request is the last byte in the
+ * stream, this status code will not be used. However, VINF_EOF is
+ * returned when attempting to read 0 bytes while standing at the end
+ * of the stream.
+ * @retval VERR_EOF when trying to read __beyond__ the end of the stream and
+ * @a pcbRead is NULL.
+ * @retval VERR_ACCESS_DENIED if the stream is not readable.
+ *
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param off Where to read at, -1 for the current position.
+ * @param pSgBuf Pointer to a scatter buffer descriptor. The number
+ * of bytes described by the segments is what will be
+ * attemted read.
+ * @param fBlocking Whether the call is blocking (@c true) or not. If
+ * not, the @a pcbRead parameter must not be NULL.
+ * @param pcbRead Where to always store the number of bytes actually
+ * read. This can be NULL if @a fBlocking is true.
+ * @sa RTFileSgRead, RTSocketSgRead, RTPipeRead, RTPipeReadBlocking
+ */
+RTDECL(int) RTVfsIoStrmSgRead(RTVFSIOSTREAM hVfsIos, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t *pcbRead);
+
+/**
+ * Write bytes to the I/O stream from a gather buffer.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_ACCESS_DENIED if the stream is not writable.
+ *
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param off Where to write at, -1 for the current position.
+ * @param pSgBuf Pointer to a gather buffer descriptor. The number
+ * of bytes described by the segments is what will be
+ * attemted written.
+ * @param fBlocking Whether the call is blocking (@c true) or not. If
+ * not, the @a pcbWritten parameter must not be NULL.
+ * @param pcbWritten Where to always store the number of bytes actually
+ * written. This can be NULL if @a fBlocking is true.
+ * @sa RTFileSgWrite, RTSocketSgWrite
+ */
+RTDECL(int) RTVfsIoStrmSgWrite(RTVFSIOSTREAM hVfsIos, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t *pcbWritten);
+
+/**
+ * Flush any buffered data to the I/O stream.
+ *
+ * @returns IPRT status code.
+ * @param hVfsIos The VFS I/O stream handle.
+ * @sa RTVfsFileFlush, RTFileFlush, RTPipeFlush
+ */
+RTDECL(int) RTVfsIoStrmFlush(RTVFSIOSTREAM hVfsIos);
+
+/**
+ * Poll for events.
+ *
+ * @returns IPRT status code.
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param fEvents The events to poll for (RTPOLL_EVT_XXX).
+ * @param cMillies How long to wait for event to eventuate.
+ * @param fIntr Whether the wait is interruptible and can return
+ * VERR_INTERRUPTED (@c true) or if this condition
+ * should be hidden from the caller (@c false).
+ * @param pfRetEvents Where to return the event mask.
+ * @sa RTVfsFilePoll, RTPollSetAdd, RTPoll, RTPollNoResume.
+ */
+RTDECL(int) RTVfsIoStrmPoll(RTVFSIOSTREAM hVfsIos, uint32_t fEvents, RTMSINTERVAL cMillies, bool fIntr,
+ uint32_t *pfRetEvents);
+/**
+ * Tells the current I/O stream position.
+ *
+ * @returns Zero or higher - where to return the I/O stream offset. Values
+ * below zero are IPRT status codes (VERR_XXX).
+ * @param hVfsIos The VFS I/O stream handle.
+ * @sa RTFileTell
+ */
+RTDECL(RTFOFF) RTVfsIoStrmTell(RTVFSIOSTREAM hVfsIos);
+
+/**
+ * Skips @a cb ahead in the stream.
+ *
+ * @returns IPRT status code.
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param cb The number bytes to skip.
+ */
+RTDECL(int) RTVfsIoStrmSkip(RTVFSIOSTREAM hVfsIos, RTFOFF cb);
+
+/**
+ * Fills the stream with @a cb zeros.
+ *
+ * @returns IPRT status code.
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param cb The number of zero bytes to insert.
+ */
+RTDECL(int) RTVfsIoStrmZeroFill(RTVFSIOSTREAM hVfsIos, RTFOFF cb);
+
+/**
+ * Checks if we're at the end of the I/O stream.
+ *
+ * @returns true if at EOS, otherwise false.
+ * @param hVfsIos The VFS I/O stream handle.
+ */
+RTDECL(bool) RTVfsIoStrmIsAtEnd(RTVFSIOSTREAM hVfsIos);
+
+/**
+ * Get the RTFILE_O_XXX flags for the I/O stream.
+ *
+ * @returns RTFILE_O_XXX, 0 on failure.
+ * @param hVfsIos The VFS I/O stream handle.
+ */
+RTDECL(uint64_t) RTVfsIoStrmGetOpenFlags(RTVFSIOSTREAM hVfsIos);
+
+/**
+ * Process the rest of the stream, checking if it's all valid UTF-8 encoding.
+ *
+ * @returns IPRT status code.
+ *
+ * @param hVfsIos The VFS I/O stream handle.
+ * @param fFlags Flags governing the validation, see
+ * RTVFS_VALIDATE_UTF8_XXX.
+ * @param poffError Where to return the error offset. Optional.
+ */
+RTDECL(int) RTVfsIoStrmValidateUtf8Encoding(RTVFSIOSTREAM hVfsIos, uint32_t fFlags, PRTFOFF poffError);
+
+/** @defgroup RTVFS_VALIDATE_UTF8_XXX RTVfsIoStrmValidateUtf8Encoding flags.
+ * @{ */
+/** The text must not contain any null terminator codepoints. */
+#define RTVFS_VALIDATE_UTF8_NO_NULL RT_BIT_32(0)
+/** The codepoints must be in the range covered by RTC-3629. */
+#define RTVFS_VALIDATE_UTF8_BY_RTC_3629 RT_BIT_32(1)
+/** Mask of valid flags. */
+#define RTVFS_VALIDATE_UTF8_VALID_MASK UINT32_C(0x00000003)
+/** @} */
+
+/** @} */
+
+
+/** @defgroup grp_vfs_file VFS File API
+ * @{
+ */
+RTDECL(int) RTVfsFileOpen(RTVFS hVfs, const char *pszFilename, uint64_t fOpen, PRTVFSFILE phVfsFile);
+
+/**
+ * Create a VFS file handle from a standard IPRT file handle (RTFILE).
+ *
+ * @returns IPRT status code.
+ * @param hFile The standard IPRT file handle.
+ * @param fOpen The flags the handle was opened with. Pass 0 to
+ * have these detected.
+ * @param fLeaveOpen Whether to leave the handle open when the VFS file
+ * is released, or to close it (@c false).
+ * @param phVfsFile Where to return the VFS file handle.
+ */
+RTDECL(int) RTVfsFileFromRTFile(RTFILE hFile, uint64_t fOpen, bool fLeaveOpen, PRTVFSFILE phVfsFile);
+RTDECL(RTHCUINTPTR) RTVfsFileToNative(RTFILE hVfsFile);
+
+/**
+ * Convenience function combining RTFileOpen with RTVfsFileFromRTFile.
+ *
+ * @returns IPRT status code.
+ * @param pszFilename The path to the file in the normal file system.
+ * @param fOpen The flags to pass to RTFileOpen when opening the
+ * file, i.e. RTFILE_O_XXX.
+ * @param phVfsFile Where to return the VFS file handle.
+ */
+RTDECL(int) RTVfsFileOpenNormal(const char *pszFilename, uint64_t fOpen, PRTVFSFILE phVfsFile);
+
+/**
+ * Convert the VFS file handle to a VFS I/O stream handle.
+ *
+ * @returns The VFS I/O stream handle on success, this must be released.
+ * NIL_RTVFSIOSTREAM if the file handle is invalid.
+ * @param hVfsFile The VFS file handle.
+ * @sa RTVfsIoStrmToFile
+ */
+RTDECL(RTVFSIOSTREAM) RTVfsFileToIoStream(RTVFSFILE hVfsFile);
+
+/**
+ * Retains a reference to the VFS file handle.
+ *
+ * @returns New reference count on success, UINT32_MAX on failure.
+ * @param hVfsFile The VFS file handle.
+ */
+RTDECL(uint32_t) RTVfsFileRetain(RTVFSFILE hVfsFile);
+RTDECL(uint32_t) RTVfsFileRetainDebug(RTVFSFILE hVfsFile, RT_SRC_POS_DECL);
+
+/**
+ * Releases a reference to the VFS file handle.
+ *
+ * @returns New reference count on success (0 if closed), UINT32_MAX on failure.
+ * @param hVfsFile The VFS file handle.
+ */
+RTDECL(uint32_t) RTVfsFileRelease(RTVFSFILE hVfsFile);
+
+/**
+ * Query information about the object.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_NOT_SUPPORTED if the @a enmAddAttr value is not handled by the
+ * implementation.
+ *
+ * @param hVfsFile The VFS file handle.
+ * @param pObjInfo Where to return the info.
+ * @param enmAddAttr Which additional attributes should be retrieved.
+ * @sa RTVfsObjQueryInfo, RTVfsFsStrmQueryInfo, RTVfsDirQueryInfo,
+ * RTVfsIoStrmQueryInfo, RTVfsFileQueryInfo, RTFileQueryInfo,
+ * RTPathQueryInfo.
+ */
+RTDECL(int) RTVfsFileQueryInfo(RTVFSFILE hVfsFile, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr);
+
+/**
+ * Read bytes from the file at the current position.
+ *
+ * @returns IPRT status code.
+ * @retval VINF_SUCCESS and the number of bytes read written to @a pcbRead.
+ * @retval VINF_EOF when trying to read __beyond__ the end of the file and
+ * @a pcbRead is not NULL (it will be set to the number of bytes read,
+ * or 0 if the end of the file was reached before this call).
+ * When the last byte of the read request is the last byte in the
+ * file, this status code will not be used. However, VINF_EOF is
+ * returned when attempting to read 0 bytes while standing at the end
+ * of the file.
+ * @retval VERR_EOF when trying to read __beyond__ the end of the file and
+ * @a pcbRead is NULL.
+ * @retval VERR_ACCESS_DENIED if the file is not readable.
+ *
+ * @param hVfsFile The VFS file handle.
+ * @param pvBuf Where to store the read bytes.
+ * @param cbToRead The number of bytes to read.
+ * @param pcbRead Where to always store the number of bytes actually
+ * read. Optional.
+ * @sa RTVfsIoStrmRead, RTFileRead, RTPipeRead, RTPipeReadBlocking,
+ * RTSocketRead
+ */
+RTDECL(int) RTVfsFileRead(RTVFSFILE hVfsFile, void *pvBuf, size_t cbToRead, size_t *pcbRead);
+RTDECL(int) RTVfsFileReadAt(RTVFSFILE hVfsFile, RTFOFF off, void *pvBuf, size_t cbToRead, size_t *pcbRead);
+
+/**
+ * Write bytes to the file at the current position.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_ACCESS_DENIED if the file is not writable.
+ *
+ * @param hVfsFile The VFS file handle.
+ * @param pvBuf The bytes to write.
+ * @param cbToWrite The number of bytes to write.
+ * @param pcbWritten Where to always store the number of bytes actually
+ * written. This can be NULL.
+ * @sa RTVfsIoStrmRead, RTFileWrite, RTPipeWrite, RTPipeWriteBlocking,
+ * RTSocketWrite
+ */
+RTDECL(int) RTVfsFileWrite(RTVFSFILE hVfsFile, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten);
+RTDECL(int) RTVfsFileWriteAt(RTVFSFILE hVfsFile, RTFOFF off, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten);
+
+
+/**
+ * Reads bytes from the file into a scatter buffer.
+ *
+ * @returns IPRT status code.
+ * @retval VINF_SUCCESS and the number of bytes read written to @a pcbRead.
+ * @retval VINF_TRY_AGAIN if @a fBlocking is @c false, @a pcbRead is not NULL,
+ * and no data was available. @a *pcbRead will be set to 0.
+ * @retval VINF_EOF when trying to read __beyond__ the end of the stream and
+ * @a pcbRead is not NULL (it will be set to the number of bytes read,
+ * or 0 if the end of the stream was reached before this call).
+ * When the last byte of the read request is the last byte in the
+ * stream, this status code will not be used. However, VINF_EOF is
+ * returned when attempting to read 0 bytes while standing at the end
+ * of the stream.
+ * @retval VERR_EOF when trying to read __beyond__ the end of the stream and
+ * @a pcbRead is NULL.
+ * @retval VERR_ACCESS_DENIED if the stream is not readable.
+ *
+ * @param hVfsFile The VFS file handle.
+ * @param off Where to read at, -1 for the current position.
+ * @param pSgBuf Pointer to a scatter buffer descriptor. The number
+ * of bytes described by the segments is what will be
+ * attemted read.
+ * @param fBlocking Whether the call is blocking (@c true) or not. If
+ * not, the @a pcbRead parameter must not be NULL.
+ * @param pcbRead Where to always store the number of bytes actually
+ * read. This can be NULL if @a fBlocking is true.
+ * @sa RTFileSgRead, RTSocketSgRead, RTPipeRead, RTPipeReadBlocking
+ */
+RTDECL(int) RTVfsFileSgRead(RTVFSFILE hVfsFile, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t *pcbRead);
+
+/**
+ * Write bytes to the file from a gather buffer.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_ACCESS_DENIED if the stream is not writable.
+ *
+ * @param hVfsFile The VFS file handle.
+ * @param off Where to write at, -1 for the current position.
+ * @param pSgBuf Pointer to a gather buffer descriptor. The number
+ * of bytes described by the segments is what will be
+ * attemted written.
+ * @param fBlocking Whether the call is blocking (@c true) or not. If
+ * not, the @a pcbWritten parameter must not be NULL.
+ * @param pcbWritten Where to always store the number of bytes actually
+ * written. This can be NULL if @a fBlocking is true.
+ * @sa RTFileSgWrite, RTSocketSgWrite
+ */
+RTDECL(int) RTVfsFileSgWrite(RTVFSFILE hVfsFile, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t *pcbWritten);
+
+/**
+ * Flush any buffered data to the file.
+ *
+ * @returns IPRT status code.
+ * @param hVfsFile The VFS file handle.
+ * @sa RTVfsIoStrmFlush, RTFileFlush, RTPipeFlush
+ */
+RTDECL(int) RTVfsFileFlush(RTVFSFILE hVfsFile);
+
+/**
+ * Poll for events.
+ *
+ * @returns IPRT status code.
+ * @param hVfsFile The VFS file handle.
+ * @param fEvents The events to poll for (RTPOLL_EVT_XXX).
+ * @param cMillies How long to wait for event to eventuate.
+ * @param fIntr Whether the wait is interruptible and can return
+ * VERR_INTERRUPTED (@c true) or if this condition
+ * should be hidden from the caller (@c false).
+ * @param pfRetEvents Where to return the event mask.
+ * @sa RTVfsIoStrmPoll, RTPollSetAdd, RTPoll, RTPollNoResume.
+ */
+RTDECL(RTFOFF) RTVfsFilePoll(RTVFSFILE hVfsFile, uint32_t fEvents, RTMSINTERVAL cMillies, bool fIntr,
+ uint32_t *pfRetEvents);
+
+/**
+ * Tells the current file position.
+ *
+ * @returns Zero or higher - where to return the file offset. Values
+ * below zero are IPRT status codes (VERR_XXX).
+ * @param hVfsFile The VFS file handle.
+ * @sa RTFileTell, RTVfsIoStrmTell.
+ */
+RTDECL(RTFOFF) RTVfsFileTell(RTVFSFILE hVfsFile);
+
+/**
+ * Changes the current read/write position of a file.
+ *
+ * @returns IPRT status code.
+ *
+ * @param hVfsFile The VFS file handle.
+ * @param offSeek The seek offset.
+ * @param uMethod The seek emthod.
+ * @param poffActual Where to optionally return the new file offset.
+ *
+ * @sa RTFileSeek
+ */
+RTDECL(int) RTVfsFileSeek(RTVFSFILE hVfsFile, RTFOFF offSeek, uint32_t uMethod, uint64_t *poffActual);
+
+/**
+ * Sets the size of a file.
+ *
+ * This may also be used for preallocating space
+ * (RTVFSFILE_SIZE_F_PREALLOC_KEEP_SIZE).
+ *
+ * @returns IPRT status code.
+ * @retval VERR_ACCESS_DENIED if handle isn't writable.
+ * @retval VERR_WRITE_PROTECT if read-only file system.
+ * @retval VERR_FILE_TOO_BIG if cbSize is larger than what the file system can
+ * theoretically deal with.
+ * @retval VERR_DISK_FULL if the file system if full.
+ * @retval VERR_NOT_SUPPORTED if fFlags indicates some operation that's not
+ * supported by the file system / host operating system.
+ *
+ * @param hVfsFile The VFS file handle.
+ * @param cbSize The new file size.
+ * @param fFlags RTVFSFILE_SIZE_F_NORMAL, RTVFSFILE_SIZE_F_GROW, or
+ * RTVFSFILE_SIZE_F_GROW_KEEP_SIZE.
+ *
+ * @sa RTFileSetSize, RTFileSetAllocationSize
+ */
+RTDECL(int) RTVfsFileSetSize(RTVFSFILE hVfsFile, uint64_t cbSize, uint32_t fFlags);
+
+/** @name RTVFSFILE_SIZE_F_XXX - RTVfsFileSetSize flags.
+ * @{ */
+/** Normal truncate or grow (zero'ed) like RTFileSetSize . */
+#define RTVFSFILE_SIZE_F_NORMAL UINT32_C(0x00000001)
+/** Only grow the file, ignore call if cbSize would trunacte the file.
+ * This is what RTFileSetAllocationSize does by default. */
+#define RTVFSFILE_SIZE_F_GROW UINT32_C(0x00000002)
+/** Only grow the file, ignore call if cbSize would trunacte the file.
+ * This is what RTFileSetAllocationSize does by default. */
+#define RTVFSFILE_SIZE_F_GROW_KEEP_SIZE UINT32_C(0x00000003)
+/** Action mask. */
+#define RTVFSFILE_SIZE_F_ACTION_MASK UINT32_C(0x00000003)
+/** Validate the flags.
+ * Will reference @a a_fFlags more than once. */
+#define RTVFSFILE_SIZE_F_IS_VALID(a_fFlags) \
+ ( !((a_fFlags) & ~RTVFSFILE_SIZE_F_ACTION_MASK) && ((a_fFlags) & RTVFSFILE_SIZE_F_ACTION_MASK) != 0 )
+/** @} */
+
+
+/** Mask of valid flags. */
+#define RTFILE_ALLOC_SIZE_F_VALID (RTFILE_ALLOC_SIZE_F_KEEP_SIZE)
+/** @} */
+
+
+RTDECL(int) RTVfsFileGetSize(RTVFSFILE hVfsFile, uint64_t *pcbSize);
+RTDECL(RTFOFF) RTVfsFileGetMaxSize(RTVFSFILE hVfsFile);
+RTDECL(int) RTVfsFileQueryMaxSize(RTVFSFILE hVfsFile, uint64_t *pcbMax);
+
+/**
+ * Get the RTFILE_O_XXX flags for the I/O stream.
+ *
+ * @returns RTFILE_O_XXX, 0 on failure.
+ * @param hVfsFile The VFS file handle.
+ */
+RTDECL(uint64_t) RTVfsFileGetOpenFlags(RTVFSFILE hVfsFile);
+
+/** @} */
+
+
+#ifdef DEBUG
+# undef RTVfsRetain
+# define RTVfsRetain(hVfs) RTVfsRetainDebug(hVfs, RT_SRC_POS)
+# undef RTVfsObjRetain
+# define RTVfsObjRetain(hVfsObj) RTVfsObjRetainDebug(hVfsObj, RT_SRC_POS)
+# undef RTVfsDirRetain
+# define RTVfsDirRetain(hVfsDir) RTVfsDirRetainDebug(hVfsDir, RT_SRC_POS)
+# undef RTVfsFileRetain
+# define RTVfsFileRetain(hVfsFile) RTVfsFileRetainDebug(hVfsFile, RT_SRC_POS)
+# undef RTVfsIoStrmRetain
+# define RTVfsIoStrmRetain(hVfsIos) RTVfsIoStrmRetainDebug(hVfsIos, RT_SRC_POS)
+# undef RTVfsFsStrmRetain
+# define RTVfsFsStrmRetain(hVfsFss) RTVfsFsStrmRetainDebug(hVfsFss, RT_SRC_POS)
+#endif
+
+
+
+/** @defgroup grp_vfs_misc VFS Miscellaneous
+ * @{
+ */
+
+/**
+ * Memorizes the I/O stream as a file backed by memory.
+ *
+ * @returns IPRT status code.
+ *
+ * @param hVfsIos The VFS I/O stream to memorize. This will be read
+ * to the end on success, on failure its position is
+ * undefined.
+ * @param fFlags A combination of RTFILE_O_READ and RTFILE_O_WRITE.
+ * @param phVfsFile Where to return the handle to the memory file on
+ * success.
+ */
+RTDECL(int) RTVfsMemorizeIoStreamAsFile(RTVFSIOSTREAM hVfsIos, uint32_t fFlags, PRTVFSFILE phVfsFile);
+
+/**
+ * Creates a VFS file from a memory buffer.
+ *
+ * @returns IPRT status code.
+ *
+ * @param fFlags A combination of RTFILE_O_READ and RTFILE_O_WRITE.
+ * @param pvBuf The buffer. This will be copied and not referenced
+ * after this function returns.
+ * @param cbBuf The buffer size.
+ * @param phVfsFile Where to return the handle to the memory file on
+ * success.
+ */
+RTDECL(int) RTVfsFileFromBuffer(uint32_t fFlags, void const *pvBuf, size_t cbBuf, PRTVFSFILE phVfsFile);
+
+/**
+ * Creates a memory backed VFS file object for read and write.
+ *
+ * @returns IPRT status code.
+ *
+ * @param hVfsIos The VFS I/O stream to memorize. This will be read
+ * to the end on success, on failure its position is
+ * undefined.
+ * @param cbEstimate The estimated file size.
+ * @param phVfsFile Where to return the handle to the memory file on
+ * success.
+ * @sa RTVfsMemIoStrmCreate
+ */
+RTDECL(int) RTVfsMemFileCreate(RTVFSIOSTREAM hVfsIos, size_t cbEstimate, PRTVFSFILE phVfsFile);
+
+/**
+ * Creates a memory backed VFS file object for read and write.
+ *
+ * @returns IPRT status code.
+ *
+ * @param hVfsIos The VFS I/O stream to memorize. This will be read
+ * to the end on success, on failure its position is
+ * undefined.
+ * @param cbEstimate The estimated file size.
+ * @param phVfsIos Where to return the handle to the memory I/O stream
+ * on success.
+ * @sa RTVfsMemFileCreate
+ */
+RTDECL(int) RTVfsMemIoStrmCreate(RTVFSIOSTREAM hVfsIos, size_t cbEstimate, PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Pumps data from one I/O stream to another.
+ *
+ * The data is read in chunks from @a hVfsIosSrc and written to @a hVfsIosDst
+ * until @a hVfsIosSrc indicates end of stream.
+ *
+ * @returns IPRT status code
+ *
+ * @param hVfsIosSrc The input stream.
+ * @param hVfsIosDst The output stream.
+ * @param cbBufHint Hints at a good temporary buffer size, pass 0 if
+ * clueless.
+ */
+RTDECL(int) RTVfsUtilPumpIoStreams(RTVFSIOSTREAM hVfsIosSrc, RTVFSIOSTREAM hVfsIosDst, size_t cbBufHint);
+
+
+/**
+ * Creates a progress wrapper for an I/O stream.
+ *
+ * @returns IRPT status code.
+ * @param hVfsIos The I/O stream to wrap.
+ * @param pfnProgress The progress callback. The return code is
+ * ignored by default, see
+ * RTVFSPROGRESS_F_CANCELABLE.
+ * @param pvUser The user argument to @a pfnProgress.
+ * @param fFlags RTVFSPROGRESS_F_XXX
+ * @param cbExpectedRead The expected number of bytes read.
+ * @param cbExpectedWritten The execpted number of bytes written.
+ * @param phVfsIos Where to return the I/O stream handle.
+ */
+RTDECL(int) RTVfsCreateProgressForIoStream(RTVFSIOSTREAM hVfsIos, PFNRTPROGRESS pfnProgress, void *pvUser, uint32_t fFlags,
+ uint64_t cbExpectedRead, uint64_t cbExpectedWritten, PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Creates a progress wrapper for a file stream.
+ *
+ * @returns IRPT status code.
+ * @param hVfsFile The file to wrap.
+ * @param pfnProgress The progress callback. The return code is
+ * ignored by default, see
+ * RTVFSPROGRESS_F_CANCELABLE.
+ * @param pvUser The user argument to @a pfnProgress.
+ * @param fFlags RTVFSPROGRESS_F_XXX
+ * @param cbExpectedRead The expected number of bytes read.
+ * @param cbExpectedWritten The execpted number of bytes written.
+ * @param phVfsFile Where to return the file handle.
+ */
+RTDECL(int) RTVfsCreateProgressForFile(RTVFSFILE hVfsFile, PFNRTPROGRESS pfnProgress, void *pvUser, uint32_t fFlags,
+ uint64_t cbExpectedRead, uint64_t cbExpectedWritten, PRTVFSFILE phVfsFile);
+
+/** @name RTVFSPROGRESS_F_XXX - Flags for RTVfsCreateProcessForIoStream and
+ * RTVfsCreateProcessForFile.
+ * @{ */
+/** Cancel if the callback returns a failure status code.
+ * This isn't default behavior because the cancelation is delayed one I/O
+ * operation in most cases and it's uncertain how the VFS user will handle the
+ * cancellation status code. */
+#define RTVFSPROGRESS_F_CANCELABLE RT_BIT_32(0)
+/** Account forward seeks as reads. */
+#define RTVFSPROGRESS_F_FORWARD_SEEK_AS_READ RT_BIT_32(1)
+/** Account fprward seeks as writes. */
+#define RTVFSPROGRESS_F_FORWARD_SEEK_AS_WRITE RT_BIT_32(2)
+/** Valid bits. */
+#define RTVFSPROGRESS_F_VALID_MASK UINT32_C(0x00000007)
+/** @} */
+
+
+/**
+ * Create an I/O stream instance performing simple sequential read-ahead.
+ *
+ * @returns IPRT status code.
+ * @param hVfsIos The input stream to perform read ahead on. If this is
+ * actually for a file object, the returned I/O stream
+ * handle can also be cast to a file handle.
+ * @param fFlags Flags reserved for future use, MBZ.
+ * @param cBuffers How many read ahead buffers to use. Specify 0 for
+ * default value.
+ * @param cbBuffer The size of each read ahead buffer. Specify 0 for
+ * default value.
+ * @param phVfsIos Where to return the read ahead I/O stream handle.
+ *
+ * @remarks Careful using this on a message pipe or socket. The reads are
+ * performed in blocked mode and it may be host and/or implementation
+ * dependent whether they will return ready data immediate or wait
+ * until there's a whole @a cbBuffer (or default) worth ready.
+ *
+ * @sa RTVfsCreateReadAheadForFile
+ */
+RTDECL(int) RTVfsCreateReadAheadForIoStream(RTVFSIOSTREAM hVfsIos, uint32_t fFlags, uint32_t cBuffers, uint32_t cbBuffer,
+ PRTVFSIOSTREAM phVfsIos);
+
+/**
+ * Create an I/O stream instance performing simple sequential read-ahead.
+ *
+ * @returns IPRT status code.
+ * @param hVfsFile The input file to perform read ahead on.
+ * @param fFlags Flags reserved for future use, MBZ.
+ * @param cBuffers How many read ahead buffers to use. Specify 0 for
+ * default value.
+ * @param cbBuffer The size of each read ahead buffer. Specify 0 for
+ * default value.
+ * @param phVfsFile Where to return the read ahead file handle.
+ * @sa RTVfsCreateReadAheadForIoStream
+ */
+RTDECL(int) RTVfsCreateReadAheadForFile(RTVFSFILE hVfsFile, uint32_t fFlags, uint32_t cBuffers, uint32_t cbBuffer,
+ PRTVFSFILE phVfsFile);
+
+
+/**
+ * Create a file system stream for writing to a directory.
+ *
+ * This is just supposed to be a drop in replacement for the TAR creator stream
+ * that instead puts the files and stuff in a directory instead of a TAR
+ * archive. In addition, it has an undo feature for simplying cleaning up after
+ * a botched run
+ *
+ * @returns IPRT status code.
+ * @param hVfsBaseDir The base directory.
+ * @param fFlags RTVFSFSS2DIR_F_XXX
+ * @param phVfsFss Where to return the FSS handle.
+ * @sa RTVfsFsStrmToNormalDir, RTVfsFsStrmToDirUndo
+ */
+RTDECL(int) RTVfsFsStrmToDir(RTVFSDIR hVfsBaseDir, uint32_t fFlags, PRTVFSFSSTREAM phVfsFss);
+
+/**
+ * Create a file system stream for writing to a normal directory.
+ *
+ * This is just supposed to be a drop in replacement for the TAR creator stream
+ * that instead puts the files and stuff in a directory instead of a TAR
+ * archive. In addition, it has an undo feature for simplying cleaning up after
+ * a botched run
+ *
+ * @returns IPRT status code.
+ * @param pszBaseDir The base directory. Must exist.
+ * @param fFlags RTVFSFSS2DIR_F_XXX
+ * @param phVfsFss Where to return the FSS handle.
+ * @sa RTVfsFsStrmToDir, RTVfsFsStrmToDirUndo
+ */
+RTDECL(int) RTVfsFsStrmToNormalDir(const char *pszBaseDir, uint32_t fFlags, PRTVFSFSSTREAM phVfsFss);
+
+/** @name RTVFSFSS2DIR_F_XXX - Flags for RTVfsFsStrmToNormalDir
+ * @{ */
+/** Overwrite existing files (default is to not overwrite anything). */
+#define RTVFSFSS2DIR_F_OVERWRITE_FILES RT_BIT_32(0)
+/** Valid bits. */
+#define RTVFSFSS2DIR_F_VALID_MASK UINT32_C(0x00000001)
+/** @} */
+
+/**
+ * Deletes files, directories, symlinks and stuff created by a FSS returned by
+ * RTVfsFsStrmToNormalDir or RTVfsFsStrmToDir.
+ *
+ * @returns IPRT status code.
+ * @param hVfsFss The write-to-directory FSS handle.
+ */
+RTDECL(int) RTVfsFsStrmToDirUndo(RTVFSFSSTREAM hVfsFss);
+
+
+
+/** @} */
+
+
+/** @defgroup grp_rt_vfs_chain VFS Chains
+ *
+ * VFS chains is for doing pipe like things with VFS objects from the command
+ * line. Imagine you want to cat the readme.gz of an ISO you could do
+ * something like:
+ * RTCat :iprtvfs:file(stdfile,live.iso)|vfs(isofs)|iso(open,readme.gz)|ios(gunzip)
+ * or
+ * RTCat :iprtvfs:file(stdfile,live.iso)|ios(isofs,readme.gz)|ios(gunzip)
+ *
+ * Or say you want to read the README.TXT on a floppy image:
+ * RTCat :iprtvfs:file(stdfile,floppy.img,r)|vfs(fat)|ios(open,README.TXT)
+ * or
+ * RTCat :iprtvfs:file(stdfile,floppy.img,r)|vfs(fat)|README.TXT
+ *
+ * Or in the other direction, you want to write a STUFF.TGZ file to the above
+ * floppy image, using a lazy writer thread for compressing the data:
+ * RTTar cf :iprtvfs:file(stdfile,floppy.img,rw)|ios(fat,STUFF.TGZ)|ios(gzip)|ios(push) .
+ *
+ *
+ * A bit more formally:
+ * :iprtvfs:{type}({provider}[,provider-args])[{separator}{type}...][{separator}{path}]
+ *
+ * The @c type refers to VFS object that should be created by the @c provider.
+ * Valid types:
+ * - vfs: A virtual file system (volume).
+ * - fss: A file system stream (e.g. tar).
+ * - ios: An I/O stream.
+ * - file: A file.
+ * - dir: A directory.
+ * - sym: A symbolic link (not sure how useful this is).
+ *
+ * The @c provider refers to registered chain element providers (see
+ * RTVFSCHAINELEMENTREG for how that works internally). These are asked to
+ * create a VFS object of the specified type using the given arguments (if any).
+ * Default providers:
+ * - std: Standard file, directory and file system.
+ * - open: Opens a file, I/O stream or directory in a vfs or directory object.
+ * - pull: Read-ahead buffering thread on file or I/O stream.
+ * - push: Lazy-writer buffering thread on file or I/O stream.
+ * - gzip: Compresses an I/O stream.
+ * - gunzip: Decompresses an I/O stream.
+ * - fat: FAT file system accessor.
+ * - isofs: ISOFS file system accessor.
+ *
+ * As element @c separator we allow both colon (':') and the pipe character
+ * ('|'). The latter the conventional one, but since it's inconvenient on the
+ * command line, colon is provided as an alternative.
+ *
+ * In the final element we allow a simple @a path to be specified instead of the
+ * type-provider-arguments stuff. The previous object must be a directory, file
+ * system or file system stream. The application will determin exactly which
+ * operation or operations which will be performed.
+ *
+ * @{
+ */
+
+/** The path prefix used to identify an VFS chain specification. */
+#define RTVFSCHAIN_SPEC_PREFIX ":iprtvfs:"
+
+RTDECL(int) RTVfsChainOpenVfs(const char *pszSpec, PRTVFS phVfs, uint32_t *poffError, PRTERRINFO pErrInfo);
+RTDECL(int) RTVfsChainOpenFsStream(const char *pszSpec, PRTVFSFSSTREAM phVfsFss, uint32_t *poffError, PRTERRINFO pErrInfo);
+
+/**
+ * Opens any kind of file system object.
+ *
+ * @returns IPRT status code.
+ * @param pszSpec The VFS chain specification or plain path.
+ * @param fFileOpen RTFILE_O_XXX flags.
+ * @param fObjFlags More flags: RTVFSOBJ_F_XXX, RTPATH_F_XXX.
+ * @param phVfsObj Where to return the handle to the opened object.
+ * @param poffError Where to on error return an offset into @a pszSpec
+ * of what cause the error. Optional.
+ * @param pErrInfo Where to return additional error information.
+ * Optional.
+ */
+RTDECL(int) RTVfsChainOpenObj(const char *pszSpec, uint64_t fFileOpen, uint32_t fObjFlags,
+ PRTVFSOBJ phVfsObj, uint32_t *poffError, PRTERRINFO pErrInfo);
+
+RTDECL(int) RTVfsChainOpenDir(const char *pszSpec, uint32_t fOpen, PRTVFSDIR phVfsDir, uint32_t *poffError, PRTERRINFO pErrInfo);
+RTDECL(int) RTVfsChainOpenParentDir(const char *pszSpec, uint32_t fOpen, PRTVFSDIR phVfsDir, const char **ppszChild,
+ uint32_t *poffError, PRTERRINFO pErrInfo);
+RTDECL(int) RTVfsChainOpenFile(const char *pszSpec, uint64_t fOpen, PRTVFSFILE phVfsFile, uint32_t *poffError, PRTERRINFO pErrInfo);
+RTDECL(int) RTVfsChainOpenIoStream(const char *pszSpec, uint64_t fOpen, PRTVFSIOSTREAM phVfsIos, uint32_t *poffError, PRTERRINFO pErrInfo);
+RTDECL(int) RTVfsChainOpenSymlink(const char *pszSpec, PRTVFSSYMLINK phVfsSym, uint32_t *poffError, PRTERRINFO pErrInfo);
+
+RTDECL(int) RTVfsChainQueryInfo(const char *pszSpec, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs,
+ uint32_t fFlags, uint32_t *poffError, PRTERRINFO pErrInfo);
+
+/**
+ * Tests if the given string is a chain specification or not.
+ *
+ * @returns true if it is, false if it isn't.
+ * @param pszSpec The alleged chain spec.
+ */
+RTDECL(bool) RTVfsChainIsSpec(const char *pszSpec);
+
+/**
+ * Queries the path from the final element.
+ *
+ * @returns IPRT status code.
+ * @retval VERR_VFS_CHAIN_NOT_PATH_ONLY if the final element isn't just a
+ * simple path.
+ * @param pszSpec The chain spec.
+ * @param ppszFinalPath Where to return a copy of the final path on success.
+ * Call RTStrFree when done.
+ * @param poffError Where to on error return an offset into @a pszSpec
+ * of what cause the error. Optional.
+ *
+ */
+RTDECL(int) RTVfsChainQueryFinalPath(const char *pszSpec, char **ppszFinalPath, uint32_t *poffError);
+
+/**
+ * Splits the given chain spec into a final path and the preceeding spec.
+ *
+ * This works on plain paths too.
+ *
+ * @returns IPRT status code.
+ * @param pszSpec The chain spec to split. This will be modified!
+ * @param ppszSpec Where to return the pointer to the chain spec part.
+ * This is set to NULL if it's a plain path or a chain
+ * spec with only a final-path element.
+ * @param ppszFinalPath Where to return the pointer to the final path. This
+ * is set to NULL if no final path.
+ * @param poffError Where to on error return an offset into @a pszSpec
+ * of what cause the error. Optional.
+ */
+RTDECL(int) RTVfsChainSplitOffFinalPath(char *pszSpec, char **ppszSpec, char **ppszFinalPath, uint32_t *poffError);
+
+/**
+ * Common code for reporting errors of a RTVfsChainOpen* API.
+ *
+ * @param pszFunction The API called.
+ * @param pszSpec The VFS chain specification or file path passed to the.
+ * @param rc The return code.
+ * @param offError The error offset value returned (0 if not captured).
+ * @param pErrInfo Additional error information. Optional.
+ *
+ * @sa RTVfsChainMsgErrorExitFailure
+ * @sa RTVfsChainOpenVfs, RTVfsChainOpenFsStream, RTVfsChainOpenDir,
+ * RTVfsChainOpenFile, RTVfsChainOpenIoStream, RTVfsChainOpenSymlink
+ */
+RTDECL(void) RTVfsChainMsgError(const char *pszFunction, const char *pszSpec, int rc, uint32_t offError, PRTERRINFO pErrInfo);
+
+/**
+ * Common code for reporting errors of a RTVfsChainOpen* API.
+ *
+ * @returns RTEXITCODE_FAILURE
+ *
+ * @param pszFunction The API called.
+ * @param pszSpec The VFS chain specification or file path passed to the.
+ * @param rc The return code.
+ * @param offError The error offset value returned (0 if not captured).
+ * @param pErrInfo Additional error information. Optional.
+ *
+ * @sa RTVfsChainMsgError
+ * @sa RTVfsChainOpenVfs, RTVfsChainOpenFsStream, RTVfsChainOpenDir,
+ * RTVfsChainOpenFile, RTVfsChainOpenIoStream, RTVfsChainOpenSymlink
+ */
+RTDECL(RTEXITCODE) RTVfsChainMsgErrorExitFailure(const char *pszFunction, const char *pszSpec,
+ int rc, uint32_t offError, PRTERRINFO pErrInfo);
+
+
+/** @} */
+
+
+/** @} */
+
+RT_C_DECLS_END
+
+#endif /* !IPRT_INCLUDED_vfs_h */
+