vfsstdfile.cpp@ 74525

Last change on this file since 74525 was 73097, checked in by vboxsync, 6 years ago
*: Made RT_UOFFSETOF, RT_OFFSETOF, RT_UOFFSETOF_ADD and RT_OFFSETOF_ADD work like builtin_offsetof() and require compile time resolvable requests, adding RT_UOFFSETOF_DYN for the dynamic questions that can only be answered at runtime.
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 19.5 KB

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1	/* $Id: vfsstdfile.cpp 73097 2018-07-12 21:06:33Z vboxsync $ */
2	/** @file
3	* IPRT - Virtual File System, Standard File Implementation.
4	*/
5
6	/*
7	* Copyright (C) 2010-2017 Oracle Corporation
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*/
26
27
28	/*********************************************************************************************************************************
29	* Header Files *
30	*********************************************************************************************************************************/
31	#include <iprt/vfs.h>
32	#include <iprt/vfslowlevel.h>
33
34	#include <iprt/assert.h>
35	#include <iprt/err.h>
36	#include <iprt/file.h>
37	#include <iprt/poll.h>
38	#include <iprt/string.h>
39	#include <iprt/thread.h>
40
41
42	/*********************************************************************************************************************************
43	* Structures and Typedefs *
44	*********************************************************************************************************************************/
45	/**
46	* Private data of a standard file.
47	*/
48	typedef struct RTVFSSTDFILE
49	{
50	/** The file handle. */
51	RTFILE hFile;
52	/** Whether to leave the handle open when the VFS handle is closed. */
53	bool fLeaveOpen;
54	} RTVFSSTDFILE;
55	/** Pointer to the private data of a standard file. */
56	typedef RTVFSSTDFILE *PRTVFSSTDFILE;
57
58
59	/**
60	* @interface_method_impl{RTVFSOBJOPS,pfnClose}
61	*/
62	static DECLCALLBACK(int) rtVfsStdFile_Close(void *pvThis)
63	{
64	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
65
66	int rc;
67	if (!pThis->fLeaveOpen)
68	rc = RTFileClose(pThis->hFile);
69	else
70	rc = VINF_SUCCESS;
71	pThis->hFile = NIL_RTFILE;
72
73	return rc;
74	}
75
76
77	/**
78	* @interface_method_impl{RTVFSOBJOPS,pfnQueryInfo}
79	*/
80	static DECLCALLBACK(int) rtVfsStdFile_QueryInfo(void *pvThis, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr)
81	{
82	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
83	return RTFileQueryInfo(pThis->hFile, pObjInfo, enmAddAttr);
84	}
85
86
87	/**
88	* RTFileRead and RTFileReadAt does not return VINF_EOF or VINF_TRY_AGAIN, this
89	* function tries to fix this as best as it can.
90	*
91	* This fixing can be subject to races if some other thread or process is
92	* modifying the file size between the read and our size query here.
93	*
94	* @returns VINF_SUCCESS, VINF_EOF or VINF_TRY_AGAIN.
95	* @param pThis The instance data.
96	* @param off The offset parameter.
97	* @param cbToRead The number of bytes attempted read .
98	* @param cbActuallyRead The number of bytes actually read.
99	*/
100	DECLINLINE(int) rtVfsStdFile_ReadFixRC(PRTVFSSTDFILE pThis, RTFOFF off, size_t cbToRead, size_t cbActuallyRead)
101	{
102	/* If the read returned less bytes than requested, it means the end of the
103	file has been reached. */
104	if (cbToRead > cbActuallyRead)
105	return VINF_EOF;
106
107	/* The other case here is the very special zero byte read at the end of the
108	file, where we're supposed to indicate EOF. */
109	if (cbToRead > 0)
110	return VINF_SUCCESS;
111
112	uint64_t cbFile;
113	int rc = RTFileGetSize(pThis->hFile, &cbFile);
114	if (RT_FAILURE(rc))
115	return rc;
116
117	uint64_t off2;
118	if (off >= 0)
119	off2 = off;
120	else
121	{
122	rc = RTFileSeek(pThis->hFile, 0, RTFILE_SEEK_CURRENT, &off2);
123	if (RT_FAILURE(rc))
124	return rc;
125	}
126
127	return off2 >= cbFile ? VINF_EOF : VINF_SUCCESS;
128	}
129
130
131	/**
132	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnRead}
133	*/
134	static DECLCALLBACK(int) rtVfsStdFile_Read(void pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t pcbRead)
135	{
136	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
137	int rc;
138
139	NOREF(fBlocking);
140	if (pSgBuf->cSegs == 1)
141	{
142	if (off < 0)
143	rc = RTFileRead( pThis->hFile, pSgBuf->paSegs[0].pvSeg, pSgBuf->paSegs[0].cbSeg, pcbRead);
144	else
145	rc = RTFileReadAt(pThis->hFile, off, pSgBuf->paSegs[0].pvSeg, pSgBuf->paSegs[0].cbSeg, pcbRead);
146	if (rc == VINF_SUCCESS && pcbRead)
147	rc = rtVfsStdFile_ReadFixRC(pThis, off, pSgBuf->paSegs[0].cbSeg, *pcbRead);
148	}
149	else
150	{
151	size_t cbSeg = 0;
152	size_t cbRead = 0;
153	size_t cbReadSeg = 0;
154	rc = VINF_SUCCESS;
155
156	for (uint32_t iSeg = 0; iSeg < pSgBuf->cSegs; iSeg++)
157	{
158	void *pvSeg = pSgBuf->paSegs[iSeg].pvSeg;
159	cbSeg = pSgBuf->paSegs[iSeg].cbSeg;
160
161	cbReadSeg = cbSeg;
162	if (off < 0)
163	rc = RTFileRead( pThis->hFile, pvSeg, cbSeg, pcbRead ? &cbReadSeg : NULL);
164	else
165	rc = RTFileReadAt(pThis->hFile, off, pvSeg, cbSeg, pcbRead ? &cbReadSeg : NULL);
166	if (RT_FAILURE(rc))
167	break;
168	if (off >= 0)
169	off += cbReadSeg;
170	cbRead += cbReadSeg;
171	if ((pcbRead && cbReadSeg != cbSeg) \|\| rc != VINF_SUCCESS)
172	break;
173	}
174
175	if (pcbRead)
176	{
177	*pcbRead = cbRead;
178	if (rc == VINF_SUCCESS)
179	rc = rtVfsStdFile_ReadFixRC(pThis, off, cbSeg, cbReadSeg);
180	}
181	}
182
183	return rc;
184	}
185
186
187	/**
188	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnWrite}
189	*/
190	static DECLCALLBACK(int) rtVfsStdFile_Write(void pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t pcbWritten)
191	{
192	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
193	int rc;
194
195	NOREF(fBlocking);
196	if (pSgBuf->cSegs == 1)
197	{
198	if (off < 0)
199	rc = RTFileWrite(pThis->hFile, pSgBuf->paSegs[0].pvSeg, pSgBuf->paSegs[0].cbSeg, pcbWritten);
200	else
201	rc = RTFileWriteAt(pThis->hFile, off, pSgBuf->paSegs[0].pvSeg, pSgBuf->paSegs[0].cbSeg, pcbWritten);
202	}
203	else
204	{
205	size_t cbWritten = 0;
206	size_t cbWrittenSeg;
207	size_t *pcbWrittenSeg = pcbWritten ? &cbWrittenSeg : NULL;
208	rc = VINF_SUCCESS;
209
210	for (uint32_t iSeg = 0; iSeg < pSgBuf->cSegs; iSeg++)
211	{
212	void *pvSeg = pSgBuf->paSegs[iSeg].pvSeg;
213	size_t cbSeg = pSgBuf->paSegs[iSeg].cbSeg;
214
215	cbWrittenSeg = 0;
216	if (off < 0)
217	rc = RTFileWrite(pThis->hFile, pvSeg, cbSeg, pcbWrittenSeg);
218	else
219	{
220	rc = RTFileWriteAt(pThis->hFile, off, pvSeg, cbSeg, pcbWrittenSeg);
221	off += cbSeg;
222	}
223	if (RT_FAILURE(rc))
224	break;
225	if (pcbWritten)
226	{
227	cbWritten += cbWrittenSeg;
228	if (cbWrittenSeg != cbSeg)
229	break;
230	}
231	}
232
233	if (pcbWritten)
234	*pcbWritten = cbWritten;
235	}
236
237	return rc;
238	}
239
240
241	/**
242	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnFlush}
243	*/
244	static DECLCALLBACK(int) rtVfsStdFile_Flush(void *pvThis)
245	{
246	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
247	int rc = RTFileFlush(pThis->hFile);
248	#ifdef RT_OS_WINDOWS
249	/* Workaround for console handles. / /* @todo push this further down? */
250	if ( rc == VERR_INVALID_HANDLE
251	&& RTFileIsValid(pThis->hFile))
252	rc = VINF_NOT_SUPPORTED; /* not flushable */
253	#endif
254	return rc;
255	}
256
257
258	/**
259	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnPollOne}
260	*/
261	static DECLCALLBACK(int) rtVfsStdFile_PollOne(void *pvThis, uint32_t fEvents, RTMSINTERVAL cMillies, bool fIntr,
262	uint32_t *pfRetEvents)
263	{
264	NOREF(pvThis);
265	int rc;
266	if (fEvents != RTPOLL_EVT_ERROR)
267	{
268	*pfRetEvents = fEvents & ~RTPOLL_EVT_ERROR;
269	rc = VINF_SUCCESS;
270	}
271	else if (fIntr)
272	rc = RTThreadSleep(cMillies);
273	else
274	{
275	uint64_t uMsStart = RTTimeMilliTS();
276	do
277	rc = RTThreadSleep(cMillies);
278	while ( rc == VERR_INTERRUPTED
279	&& !fIntr
280	&& RTTimeMilliTS() - uMsStart < cMillies);
281	if (rc == VERR_INTERRUPTED)
282	rc = VERR_TIMEOUT;
283	}
284	return rc;
285	}
286
287
288	/**
289	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnTell}
290	*/
291	static DECLCALLBACK(int) rtVfsStdFile_Tell(void *pvThis, PRTFOFF poffActual)
292	{
293	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
294	uint64_t offActual;
295	int rc = RTFileSeek(pThis->hFile, 0, RTFILE_SEEK_CURRENT, &offActual);
296	if (RT_SUCCESS(rc))
297	*poffActual = (RTFOFF)offActual;
298	return rc;
299	}
300
301
302	/**
303	* @interface_method_impl{RTVFSIOSTREAMOPS,pfnSkip}
304	*/
305	static DECLCALLBACK(int) rtVfsStdFile_Skip(void *pvThis, RTFOFF cb)
306	{
307	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
308	uint64_t offIgnore;
309	return RTFileSeek(pThis->hFile, cb, RTFILE_SEEK_CURRENT, &offIgnore);
310	}
311
312
313	/**
314	* @interface_method_impl{RTVFSOBJSETOPS,pfnMode}
315	*/
316	static DECLCALLBACK(int) rtVfsStdFile_SetMode(void *pvThis, RTFMODE fMode, RTFMODE fMask)
317	{
318	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
319	if (fMask != ~RTFS_TYPE_MASK)
320	{
321	#if 0
322	RTFMODE fCurMode;
323	int rc = RTFileGetMode(pThis->hFile, &fCurMode);
324	if (RT_FAILURE(rc))
325	return rc;
326	fMode \|= ~fMask & fCurMode;
327	#else
328	RTFSOBJINFO ObjInfo;
329	int rc = RTFileQueryInfo(pThis->hFile, &ObjInfo, RTFSOBJATTRADD_NOTHING);
330	if (RT_FAILURE(rc))
331	return rc;
332	fMode \|= ~fMask & ObjInfo.Attr.fMode;
333	#endif
334	}
335	return RTFileSetMode(pThis->hFile, fMode);
336	}
337
338
339	/**
340	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetTimes}
341	*/
342	static DECLCALLBACK(int) rtVfsStdFile_SetTimes(void *pvThis, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime,
343	PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime)
344	{
345	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
346	return RTFileSetTimes(pThis->hFile, pAccessTime, pModificationTime, pChangeTime, pBirthTime);
347	}
348
349
350	/**
351	* @interface_method_impl{RTVFSOBJSETOPS,pfnSetOwner}
352	*/
353	static DECLCALLBACK(int) rtVfsStdFile_SetOwner(void *pvThis, RTUID uid, RTGID gid)
354	{
355	#if 0
356	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
357	return RTFileSetOwner(pThis->hFile, uid, gid);
358	#else
359	NOREF(pvThis); NOREF(uid); NOREF(gid);
360	return VERR_NOT_IMPLEMENTED;
361	#endif
362	}
363
364
365	/**
366	* @interface_method_impl{RTVFSFILEOPS,pfnSeek}
367	*/
368	static DECLCALLBACK(int) rtVfsStdFile_Seek(void *pvThis, RTFOFF offSeek, unsigned uMethod, PRTFOFF poffActual)
369	{
370	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
371	uint64_t offActual = 0;
372	int rc = RTFileSeek(pThis->hFile, offSeek, uMethod, &offActual);
373	if (RT_SUCCESS(rc))
374	*poffActual = offActual;
375	return rc;
376	}
377
378
379	/**
380	* @interface_method_impl{RTVFSFILEOPS,pfnQuerySize}
381	*/
382	static DECLCALLBACK(int) rtVfsStdFile_QuerySize(void pvThis, uint64_t pcbFile)
383	{
384	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
385	return RTFileGetSize(pThis->hFile, pcbFile);
386	}
387
388
389	/**
390	* @interface_method_impl{RTVFSFILEOPS,pfnSetSize}
391	*/
392	static DECLCALLBACK(int) rtVfsStdFile_SetSize(void *pvThis, uint64_t cbFile, uint32_t fFlags)
393	{
394	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
395	switch (fFlags & RTVFSFILE_SIZE_F_ACTION_MASK)
396	{
397	case RTVFSFILE_SIZE_F_NORMAL:
398	return RTFileSetSize(pThis->hFile, cbFile);
399	case RTVFSFILE_SIZE_F_GROW:
400	return RTFileSetAllocationSize(pThis->hFile, cbFile, RTFILE_ALLOC_SIZE_F_DEFAULT);
401	case RTVFSFILE_SIZE_F_GROW_KEEP_SIZE:
402	return RTFileSetAllocationSize(pThis->hFile, cbFile, RTFILE_ALLOC_SIZE_F_KEEP_SIZE);
403	default:
404	return VERR_NOT_SUPPORTED;
405	}
406	}
407
408
409	/**
410	* @interface_method_impl{RTVFSFILEOPS,pfnQueryMaxSize}
411	*/
412	static DECLCALLBACK(int) rtVfsStdFile_QueryMaxSize(void pvThis, uint64_t pcbMax)
413	{
414	PRTVFSSTDFILE pThis = (PRTVFSSTDFILE)pvThis;
415	RTFOFF cbMax = 0;
416	int rc = RTFileGetMaxSizeEx(pThis->hFile, &cbMax);
417	if (RT_SUCCESS(rc))
418	*pcbMax = cbMax;
419	return rc;
420	}
421
422
423	/**
424	* Standard file operations.
425	*/
426	DECL_HIDDEN_CONST(const RTVFSFILEOPS) g_rtVfsStdFileOps =
427	{
428	{ /* Stream */
429	{ /* Obj */
430	RTVFSOBJOPS_VERSION,
431	RTVFSOBJTYPE_FILE,
432	"StdFile",
433	rtVfsStdFile_Close,
434	rtVfsStdFile_QueryInfo,
435	RTVFSOBJOPS_VERSION
436	},
437	RTVFSIOSTREAMOPS_VERSION,
438	0,
439	rtVfsStdFile_Read,
440	rtVfsStdFile_Write,
441	rtVfsStdFile_Flush,
442	rtVfsStdFile_PollOne,
443	rtVfsStdFile_Tell,
444	rtVfsStdFile_Skip,
445	NULL /ZeroFill/,
446	RTVFSIOSTREAMOPS_VERSION,
447	},
448	RTVFSFILEOPS_VERSION,
449	0,
450	{ /* ObjSet */
451	RTVFSOBJSETOPS_VERSION,
452	RT_UOFFSETOF(RTVFSFILEOPS, ObjSet) - RT_UOFFSETOF(RTVFSFILEOPS, Stream.Obj),
453	rtVfsStdFile_SetMode,
454	rtVfsStdFile_SetTimes,
455	rtVfsStdFile_SetOwner,
456	RTVFSOBJSETOPS_VERSION
457	},
458	rtVfsStdFile_Seek,
459	rtVfsStdFile_QuerySize,
460	rtVfsStdFile_SetSize,
461	rtVfsStdFile_QueryMaxSize,
462	RTVFSFILEOPS_VERSION
463	};
464
465
466	/**
467	* Internal worker for RTVfsFileFromRTFile and RTVfsFileOpenNormal.
468	*
469	* @returns IRPT status code.
470	* @param hFile The IPRT file handle.
471	* @param fOpen The RTFILE_O_XXX flags.
472	* @param fLeaveOpen Whether to leave it open or close it.
473	* @param phVfsFile Where to return the handle.
474	*/
475	static int rtVfsFileFromRTFile(RTFILE hFile, uint64_t fOpen, bool fLeaveOpen, PRTVFSFILE phVfsFile)
476	{
477	PRTVFSSTDFILE pThis;
478	RTVFSFILE hVfsFile;
479	int rc = RTVfsNewFile(&g_rtVfsStdFileOps, sizeof(RTVFSSTDFILE), fOpen, NIL_RTVFS, NIL_RTVFSLOCK,
480	&hVfsFile, (void **)&pThis);
481	if (RT_FAILURE(rc))
482	return rc;
483
484	pThis->hFile = hFile;
485	pThis->fLeaveOpen = fLeaveOpen;
486	*phVfsFile = hVfsFile;
487	return VINF_SUCCESS;
488	}
489
490
491	RTDECL(int) RTVfsFileFromRTFile(RTFILE hFile, uint64_t fOpen, bool fLeaveOpen, PRTVFSFILE phVfsFile)
492	{
493	/*
494	* Check the handle validity.
495	*/
496	RTFSOBJINFO ObjInfo;
497	int rc = RTFileQueryInfo(hFile, &ObjInfo, RTFSOBJATTRADD_NOTHING);
498	if (RT_FAILURE(rc))
499	return rc;
500
501	/*
502	* Set up some fake fOpen flags if necessary and create a VFS file handle.
503	*/
504	if (!fOpen)
505	fOpen = RTFILE_O_READWRITE \| RTFILE_O_DENY_NONE \| RTFILE_O_OPEN_CREATE;
506
507	return rtVfsFileFromRTFile(hFile, fOpen, fLeaveOpen, phVfsFile);
508	}
509
510
511	RTDECL(int) RTVfsFileOpenNormal(const char *pszFilename, uint64_t fOpen, PRTVFSFILE phVfsFile)
512	{
513	/*
514	* Open the file the normal way and pass it to RTVfsFileFromRTFile.
515	*/
516	RTFILE hFile;
517	int rc = RTFileOpen(&hFile, pszFilename, fOpen);
518	if (RT_SUCCESS(rc))
519	{
520	/*
521	* Create a VFS file handle.
522	*/
523	rc = rtVfsFileFromRTFile(hFile, fOpen, false /fLeaveOpen/, phVfsFile);
524	if (RT_FAILURE(rc))
525	RTFileClose(hFile);
526	}
527	return rc;
528	}
529
530
531	RTDECL(int) RTVfsIoStrmFromRTFile(RTFILE hFile, uint64_t fOpen, bool fLeaveOpen, PRTVFSIOSTREAM phVfsIos)
532	{
533	RTVFSFILE hVfsFile;
534	int rc = RTVfsFileFromRTFile(hFile, fOpen, fLeaveOpen, &hVfsFile);
535	if (RT_SUCCESS(rc))
536	{
537	*phVfsIos = RTVfsFileToIoStream(hVfsFile);
538	RTVfsFileRelease(hVfsFile);
539	}
540	return rc;
541	}
542
543
544	RTDECL(int) RTVfsIoStrmOpenNormal(const char *pszFilename, uint64_t fOpen, PRTVFSIOSTREAM phVfsIos)
545	{
546	RTVFSFILE hVfsFile;
547	int rc = RTVfsFileOpenNormal(pszFilename, fOpen, &hVfsFile);
548	if (RT_SUCCESS(rc))
549	{
550	*phVfsIos = RTVfsFileToIoStream(hVfsFile);
551	RTVfsFileRelease(hVfsFile);
552	}
553	return rc;
554	}
555
556
557
558	/**
559	* @interface_method_impl{RTVFSCHAINELEMENTREG,pfnValidate}
560	*/
561	static DECLCALLBACK(int) rtVfsChainStdFile_Validate(PCRTVFSCHAINELEMENTREG pProviderReg, PRTVFSCHAINSPEC pSpec,
562	PRTVFSCHAINELEMSPEC pElement, uint32_t *poffError, PRTERRINFO pErrInfo)
563	{
564	RT_NOREF(pProviderReg);
565
566	/*
567	* Basic checks.
568	*/
569	if (pElement->enmTypeIn != RTVFSOBJTYPE_INVALID)
570	return VERR_VFS_CHAIN_MUST_BE_FIRST_ELEMENT;
571	if ( pElement->enmType != RTVFSOBJTYPE_FILE
572	&& pElement->enmType != RTVFSOBJTYPE_IO_STREAM)
573	return VERR_VFS_CHAIN_ONLY_FILE_OR_IOS;
574
575	/*
576	* Join common cause with the 'open' provider.
577	*/
578	return RTVfsChainValidateOpenFileOrIoStream(pSpec, pElement, poffError, pErrInfo);
579	}
580
581
582	/**
583	* @interface_method_impl{RTVFSCHAINELEMENTREG,pfnInstantiate}
584	*/
585	static DECLCALLBACK(int) rtVfsChainStdFile_Instantiate(PCRTVFSCHAINELEMENTREG pProviderReg, PCRTVFSCHAINSPEC pSpec,
586	PCRTVFSCHAINELEMSPEC pElement, RTVFSOBJ hPrevVfsObj,
587	PRTVFSOBJ phVfsObj, uint32_t *poffError, PRTERRINFO pErrInfo)
588	{
589	RT_NOREF(pProviderReg, pSpec, poffError, pErrInfo);
590	AssertReturn(hPrevVfsObj == NIL_RTVFSOBJ, VERR_VFS_CHAIN_IPE);
591
592	RTVFSFILE hVfsFile;
593	int rc = RTVfsFileOpenNormal(pElement->paArgs[0].psz, pElement->uProvider, &hVfsFile);
594	if (RT_SUCCESS(rc))
595	{
596	*phVfsObj = RTVfsObjFromFile(hVfsFile);
597	RTVfsFileRelease(hVfsFile);
598	if (*phVfsObj != NIL_RTVFSOBJ)
599	return VINF_SUCCESS;
600	rc = VERR_VFS_CHAIN_CAST_FAILED;
601	}
602	return rc;
603	}
604
605
606	/**
607	* @interface_method_impl{RTVFSCHAINELEMENTREG,pfnCanReuseElement}
608	*/
609	static DECLCALLBACK(bool) rtVfsChainStdFile_CanReuseElement(PCRTVFSCHAINELEMENTREG pProviderReg,
610	PCRTVFSCHAINSPEC pSpec, PCRTVFSCHAINELEMSPEC pElement,
611	PCRTVFSCHAINSPEC pReuseSpec, PCRTVFSCHAINELEMSPEC pReuseElement)
612	{
613	RT_NOREF(pProviderReg, pSpec, pReuseSpec);
614	if (strcmp(pElement->paArgs[0].psz, pReuseElement->paArgs[0].psz) == 0)
615	if (pElement->paArgs[0].uProvider == pReuseElement->paArgs[0].uProvider)
616	return true;
617	return false;
618	}
619
620
621	/** VFS chain element 'file'. */
622	static RTVFSCHAINELEMENTREG g_rtVfsChainStdFileReg =
623	{
624	/* uVersion = */ RTVFSCHAINELEMENTREG_VERSION,
625	/* fReserved = */ 0,
626	/* pszName = */ "stdfile",
627	/* ListEntry = */ { NULL, NULL },
628	/* pszHelp = */ "Open a real file, providing either a file or an I/O stream object. Initial element.\n"
629	"First argument is the filename path.\n"
630	"Second argument is access mode, optional: r, w, rw.\n"
631	"Third argument is open disposition, optional: create, create-replace, open, open-create, open-append, open-truncate.\n"
632	"Forth argument is file sharing, optional: nr, nw, nrw, d.",
633	/* pfnValidate = */ rtVfsChainStdFile_Validate,
634	/* pfnInstantiate = */ rtVfsChainStdFile_Instantiate,
635	/* pfnCanReuseElement = */ rtVfsChainStdFile_CanReuseElement,
636	/* uEndMarker = */ RTVFSCHAINELEMENTREG_VERSION
637	};
638
639	RTVFSCHAIN_AUTO_REGISTER_ELEMENT_PROVIDER(&g_rtVfsChainStdFileReg, rtVfsChainStdFileReg);
640

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source: vbox/trunk/src/VBox/Runtime/common/vfs/vfsstdfile.cpp@ 74525

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