xref: /haiku/src/apps/diskprobe/DataEditor.cpp (revision 0c93c0a807b27096abbfad677436afb7d1712d4a)
1 /*
2  * Copyright 2004-2007, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
3  * Distributed under the terms of the MIT License.
4  */
5 
6 
7 #include "DataEditor.h"
8 
9 #include <Autolock.h>
10 #include <NodeMonitor.h>
11 #include <Directory.h>
12 #include <Drivers.h>
13 #include <fs_attr.h>
14 #include <fs_info.h>
15 
16 #include <string.h>
17 #include <unistd.h>
18 #include <ctype.h>
19 #include <errno.h>
20 
21 
22 #ifdef TRACE
23 #	undef TRACE
24 #endif
25 
26 //#define TRACE_DATA_EDITOR
27 #ifdef TRACE_DATA_EDITOR
28 #	define TRACE(x) printf x
29 #else
30 #	define TRACE(x) ;
31 #endif
32 
33 
34 class StateWatcher {
35 	public:
36 		StateWatcher(DataEditor &editor);
37 		~StateWatcher();
38 
39 	private:
40 		DataEditor	&fEditor;
41 		bool		fCouldUndo;
42 		bool		fCouldRedo;
43 		bool		fWasModified;
44 };
45 
46 class DataChange {
47 	public:
48 		virtual ~DataChange();
49 
50 		virtual void Apply(off_t offset, uint8 *buffer, size_t size) = 0;
51 		virtual void Revert(off_t offset, uint8 *buffer, size_t size) = 0;
52 		virtual bool Merge(DataChange *change);
53 		virtual void GetRange(off_t fileSize, off_t &_offset, off_t &_size) = 0;
54 };
55 
56 class ReplaceChange : public DataChange {
57 	public:
58 		ReplaceChange(off_t offset, const uint8 *data, size_t size);
59 		~ReplaceChange();
60 
61 		virtual void Apply(off_t offset, uint8 *buffer, size_t size);
62 		virtual void Revert(off_t offset, uint8 *buffer, size_t size);
63 		virtual bool Merge(DataChange *change);
64 		virtual void GetRange(off_t fileSize, off_t &_offset, off_t &_size);
65 
66 	private:
67 		void Normalize(off_t bufferOffset, size_t bufferSize,
68 			off_t &offset, size_t &dataOffset, size_t &size);
69 
70 		uint8 	*fNewData;
71 		uint8 	*fOldData;
72 		size_t	fSize;
73 		off_t	fOffset;
74 };
75 
76 
77 //---------------------
78 
79 
80 #ifdef TRACE_DATA_EDITOR
81 
82 #define DUMPED_BLOCK_SIZE 16
83 
84 static void
85 dump_block(const uint8 *buffer, int size, const char *prefix)
86 {
87 	for (int i = 0; i < size;) {
88 		int start = i;
89 
90 		printf(prefix);
91 		for (; i < start + DUMPED_BLOCK_SIZE; i++) {
92 			if (!(i % 4))
93 				printf(" ");
94 
95 			if (i >= size)
96 				printf("  ");
97 			else
98 				printf("%02x", *(unsigned char *)(buffer + i));
99 		}
100 		printf("  ");
101 
102 		for (i = start; i < start + DUMPED_BLOCK_SIZE; i++) {
103 			if (i < size) {
104 				char c = buffer[i];
105 
106 				if (c < 30)
107 					printf(".");
108 				else
109 					printf("%c", c);
110 			} else
111 				break;
112 		}
113 		printf("\n");
114 	}
115 }
116 #endif	// TRACE_DATA_EDITOR
117 
118 
119 static int
120 CompareCaseInsensitive(const uint8 *a, const uint8 *b, size_t size)
121 {
122 	for (size_t i = 0; i < size; i++) {
123 		uint8 diff = tolower(a[i]) - tolower(b[i]);
124 		if (diff)
125 			return diff;
126 	}
127 
128 	return 0;
129 }
130 
131 
132 static int
133 CompareOffsets(const off_t *a, const off_t *b)
134 {
135 	if (*a < *b)
136 		return -1;
137 	else if (*a > *b)
138 		return 1;
139 
140 	return 0;
141 }
142 
143 
144 //	#pragma mark -
145 
146 
147 StateWatcher::StateWatcher(DataEditor &editor)
148 	:
149 	fEditor(editor)
150 {
151 	fCouldUndo = editor.CanUndo();
152 	fCouldRedo = editor.CanRedo();
153 	fWasModified = editor.IsModified();
154 }
155 
156 
157 StateWatcher::~StateWatcher()
158 {
159 	BMessage update;
160 	if (fCouldRedo != fEditor.CanRedo())
161 		update.AddBool("can_redo", fEditor.CanRedo());
162 	if (fCouldUndo != fEditor.CanUndo())
163 		update.AddBool("can_undo", fEditor.CanUndo());
164 	if (fWasModified != fEditor.IsModified())
165 		update.AddBool("modified", fEditor.IsModified());
166 
167 	// only send an update if we have to report anything
168 	if (!update.IsEmpty())
169 		fEditor.SendNotices(kMsgDataEditorStateChange, &update);
170 }
171 
172 
173 //	#pragma mark -
174 
175 
176 DataChange::~DataChange()
177 {
178 }
179 
180 
181 bool
182 DataChange::Merge(DataChange *change)
183 {
184 	return false;
185 }
186 
187 
188 //	#pragma mark -
189 
190 
191 ReplaceChange::ReplaceChange(off_t offset, const uint8 *data, size_t size)
192 {
193 	fOffset = offset;
194 
195 	fNewData = (uint8 *)malloc(size);
196 	fOldData = (uint8 *)malloc(size);
197 	if (fNewData != NULL && fOldData != NULL) {
198 		memcpy(fNewData, data, size);
199 		fSize = size;
200 	} else
201 		fSize = 0;
202 }
203 
204 
205 ReplaceChange::~ReplaceChange()
206 {
207 	free(fNewData);
208 	free(fOldData);
209 }
210 
211 
212 /** Normalizes the supplied offset & size pair to be limited by
213  *	the buffer offset and size.
214  *	All parameters must have been initialized before calling this
215  *	method.
216  */
217 
218 void
219 ReplaceChange::Normalize(off_t bufferOffset, size_t bufferSize, off_t &offset,
220 	size_t &dataOffset, size_t &size)
221 {
222 	if (fOffset < bufferOffset) {
223 		offset = bufferOffset;
224 		dataOffset = bufferOffset - fOffset;
225 		size -= dataOffset;
226 	}
227 
228 	if (offset + size > bufferOffset + bufferSize)
229 		size = bufferOffset + bufferSize - offset;
230 }
231 
232 
233 void
234 ReplaceChange::Apply(off_t bufferOffset, uint8 *buffer, size_t bufferSize)
235 {
236 	// is it in our range?
237 	if (fOffset > bufferOffset + bufferSize || fOffset + fSize < bufferOffset)
238 		return;
239 
240 	// don't change anything outside the supplied buffer
241 	off_t offset = fOffset;
242 	size_t dataOffset = 0;
243 	size_t size = fSize;
244 	Normalize(bufferOffset, bufferSize, offset, dataOffset, size);
245 	if (size == 0)
246 		return;
247 
248 #ifdef TRACE_DATA_EDITOR
249 	printf("Apply %p (buffer offset = %Ld):\n", this, bufferOffset);
250 	dump_block(buffer + offset - bufferOffset, size, "old:");
251 	dump_block(fNewData + dataOffset, size, "new:");
252 #endif
253 
254 	// now we can safely exchange the buffer!
255 	memcpy(fOldData + dataOffset, buffer + offset - bufferOffset, size);
256 	memcpy(buffer + offset - bufferOffset, fNewData + dataOffset, size);
257 }
258 
259 
260 void
261 ReplaceChange::Revert(off_t bufferOffset, uint8 *buffer, size_t bufferSize)
262 {
263 	// is it in our range?
264 	if (fOffset - bufferOffset > bufferSize || fOffset + fSize < bufferOffset)
265 		return;
266 
267 	// don't change anything outside the supplied buffer
268 	off_t offset = fOffset;
269 	size_t dataOffset = 0;
270 	size_t size = fSize;
271 	Normalize(bufferOffset, bufferSize, offset, dataOffset, size);
272 	if (size == 0)
273 		return;
274 
275 #ifdef TRACE_DATA_EDITOR
276 	printf("Revert %p (buffer offset = %Ld):\n", this, bufferOffset);
277 	dump_block(buffer + offset - bufferOffset, size, "old:");
278 	dump_block(fOldData + dataOffset, size, "new:");
279 #endif
280 
281 	// now we can safely revert the buffer!
282 	memcpy(buffer + offset - bufferOffset, fOldData + dataOffset, size);
283 }
284 
285 
286 bool
287 ReplaceChange::Merge(DataChange *_change)
288 {
289 	ReplaceChange *change = dynamic_cast<ReplaceChange *>(_change);
290 	if (change == NULL)
291 		return false;
292 
293 	if (change->fOffset + change->fSize == fOffset + fSize && change->fSize == 1) {
294 		// this is a special case - the new change changed the last byte of
295 		// the old change: we do this since the same byte is changed twice
296 		// in hex mode editing.
297 		fNewData[fSize - 1] = change->fNewData[0];
298 #ifdef TRACE_DATA_EDITOR
299 		printf("Merge one byte %p (offset = %Ld, size = %lu):\n", this, fOffset, fSize);
300 		dump_block(fOldData, fSize, "old:");
301 		dump_block(fNewData, fSize, "new:");
302 #endif
303 		return true;
304 	}
305 
306 	// are the changes adjacent?
307 
308 	if (change->fOffset + change->fSize != fOffset
309 		&& fOffset + fSize != change->fOffset)
310 		return false;
311 
312 	// okay, we can try to merge the two changes
313 
314 	uint8 *newData = fOffset < change->fOffset ? fNewData : change->fNewData;
315 	size_t size = fSize + change->fSize;
316 
317 	if ((newData = (uint8 *)realloc(newData, size)) == NULL)
318 		return false;
319 
320 	uint8 *oldData = fOffset < change->fOffset ? fOldData : change->fOldData;
321 	if ((oldData = (uint8 *)realloc(oldData, size)) == NULL) {
322 		fNewData = (uint8 *)realloc(newData, fSize);
323 			// if this fails, we can't do anything about it
324 		return false;
325 	}
326 
327 	if (fOffset < change->fOffset) {
328 		memcpy(newData + fSize, change->fNewData, change->fSize);
329 		memcpy(oldData + fSize, change->fOldData, change->fSize);
330 	} else {
331 		memcpy(newData + change->fSize, fNewData, fSize);
332 		memcpy(oldData + change->fSize, fOldData, fSize);
333 		change->fNewData = fNewData;
334 		change->fOldData = fOldData;
335 			// transfer ownership, so that they will be deleted with the change
336 		fOffset = change->fOffset;
337 	}
338 
339 	fNewData = newData;
340 	fOldData = oldData;
341 	fSize = size;
342 
343 #ifdef TRACE_DATA_EDITOR
344 	printf("Merge %p (offset = %Ld, size = %lu):\n", this, fOffset, fSize);
345 	dump_block(fOldData, fSize, "old:");
346 	dump_block(fNewData, fSize, "new:");
347 #endif
348 
349 	return true;
350 }
351 
352 
353 void
354 ReplaceChange::GetRange(off_t /*fileSize*/, off_t &_offset, off_t &_size)
355 {
356 	_offset = fOffset;
357 	_size = fSize;
358 }
359 
360 
361 //	#pragma mark -
362 
363 
364 DataEditor::DataEditor()
365 	: BLocker("data view")
366 {
367 }
368 
369 
370 DataEditor::DataEditor(entry_ref &ref, const char *attribute)
371 	: BLocker("data view")
372 {
373 	SetTo(ref, attribute);
374 }
375 
376 
377 DataEditor::DataEditor(BEntry &entry, const char *attribute)
378 	: BLocker("data view")
379 {
380 	SetTo(entry, attribute);
381 }
382 
383 
384 DataEditor::DataEditor(const DataEditor &editor)
385 	: BLocker("data view")
386 {
387 }
388 
389 
390 DataEditor::~DataEditor()
391 {
392 }
393 
394 
395 status_t
396 DataEditor::SetTo(const char *path, const char *attribute)
397 {
398 	BEntry entry(path);
399 	return SetTo(entry, attribute);
400 }
401 
402 
403 status_t
404 DataEditor::SetTo(entry_ref &ref, const char *attribute)
405 {
406 	BEntry entry(&ref);
407 	return SetTo(entry, attribute);
408 }
409 
410 
411 status_t
412 DataEditor::SetTo(BEntry &entry, const char *attribute)
413 {
414 	fSize = 0;
415 	fLastChange = fFirstChange = NULL;
416 	fChangesFromSaved = 0;
417 	fView = NULL;
418 	fRealViewOffset = 0;
419 	fViewOffset = 0;
420 	fRealViewSize = fViewSize = fBlockSize = 512;
421 
422 	struct stat stat;
423 	status_t status = entry.GetStat(&stat);
424 	if (status < B_OK)
425 		return status;
426 
427 	entry.GetRef(&fAttributeRef);
428 
429 	bool isFileSystem = false;
430 
431 	if (entry.IsDirectory()) {
432 		// we redirect root directories to their volumes
433 		BDirectory directory(&entry);
434 		if (directory.InitCheck() == B_OK && directory.IsRootDirectory()) {
435 			fs_info info;
436 			if (fs_stat_dev(stat.st_dev, &info) != 0)
437 				return errno;
438 
439 			status = entry.SetTo(info.device_name);
440 			if (status < B_OK)
441 				return status;
442 
443 			entry.GetStat(&stat);
444 
445 			fBlockSize = info.block_size;
446 			if (fBlockSize > 0 && fBlockSize <= 65536)
447 				isFileSystem = true;
448 		}
449 	}
450 
451 	status = fFile.SetTo(&entry, B_READ_WRITE);
452 	if (status < B_OK) {
453 		// try to open read only
454 		status = fFile.SetTo(&entry, B_READ_ONLY);
455 		if (status < B_OK)
456 			return status;
457 
458 		fIsReadOnly = true;
459 	} else
460 		fIsReadOnly = false;
461 
462 	entry.GetRef(&fRef);
463 	fIsDevice = S_ISBLK(stat.st_mode) || S_ISCHR(stat.st_mode);
464 
465 	if (attribute != NULL)
466 		fAttribute = strdup(attribute);
467 	else
468 		fAttribute = NULL;
469 
470 	if (IsAttribute()) {
471 		BNode node(&fAttributeRef);
472 		attr_info info;
473 		status = node.GetAttrInfo(fAttribute, &info);
474 		if (status != B_OK) {
475 			fFile.Unset();
476 			return status;
477 		}
478 
479 		fSize = info.size;
480 		fType = info.type;
481 	} else if (fIsDevice) {
482 		device_geometry geometry;
483 		int device = fFile.Dup();
484 		if (device < 0 || ioctl(device, B_GET_GEOMETRY, &geometry) < 0) {
485 			if (device >= 0)
486 				close(device);
487 			fFile.Unset();
488 			return B_ERROR;
489 		}
490 		close(device);
491 
492 		fSize = 1LL * geometry.head_count * geometry.cylinder_count
493 			* geometry.sectors_per_track * geometry.bytes_per_sector;
494 
495 		if (!isFileSystem)
496 			fBlockSize = geometry.bytes_per_sector;
497 	} else if (entry.IsDirectory() || entry.IsSymLink()) {
498 		fSize = 0;
499 		fIsReadOnly = true;
500 	} else {
501 		status = fFile.GetSize(&fSize);
502 		if (status < B_OK) {
503 			fFile.Unset();
504 			return status;
505 		}
506 	}
507 
508 	if (fBlockSize == 0)
509 		fBlockSize = 512;
510 
511 	fRealViewSize = fViewSize = fBlockSize;
512 	fNeedsUpdate = true;
513 
514 	return B_OK;
515 }
516 
517 
518 status_t
519 DataEditor::InitCheck()
520 {
521 	return fFile.InitCheck();
522 }
523 
524 
525 void
526 DataEditor::AddChange(DataChange *change)
527 {
528 	if (change == NULL)
529 		return;
530 
531 	StateWatcher watcher(*this);
532 		// update state observers
533 
534 	RemoveRedos();
535 	change->Apply(fRealViewOffset, fView, fRealViewSize);
536 
537 	SendNotices(change);
538 		// update observers
539 
540 	// try to join changes
541 	if (fLastChange == NULL || !fLastChange->Merge(change)) {
542 		fChanges.AddItem(change);
543 		fLastChange = change;
544 		fChangesFromSaved++;
545 	} else
546 		delete change;
547 }
548 
549 
550 status_t
551 DataEditor::Replace(off_t offset, const uint8 *data, size_t length)
552 {
553 	if (IsReadOnly())
554 		return B_NOT_ALLOWED;
555 
556 	BAutolock locker(this);
557 
558 	if (offset >= fSize)
559 		return B_BAD_VALUE;
560 	if (offset + length > fSize)
561 		length = fSize - offset;
562 
563 	if (fNeedsUpdate) {
564 		status_t status = Update();
565 		if (status < B_OK)
566 			return status;
567 	}
568 
569 	ReplaceChange *change = new ReplaceChange(offset, data, length);
570 	AddChange(change);
571 
572 	return B_OK;
573 }
574 
575 
576 status_t
577 DataEditor::Remove(off_t offset, off_t length)
578 {
579 	if (IsReadOnly())
580 		return B_NOT_ALLOWED;
581 
582 	BAutolock locker(this);
583 
584 	// not yet implemented
585 	// ToDo: this needs some changes to the whole change mechanism
586 
587 	return B_ERROR;
588 }
589 
590 
591 status_t
592 DataEditor::Insert(off_t offset, const uint8 *text, size_t length)
593 {
594 	if (IsReadOnly())
595 		return B_NOT_ALLOWED;
596 
597 	BAutolock locker(this);
598 
599 	// not yet implemented
600 	// ToDo: this needs some changes to the whole change mechanism
601 
602 	return B_ERROR;
603 }
604 
605 
606 void
607 DataEditor::ApplyChanges()
608 {
609 	if (fLastChange == NULL && fFirstChange == NULL)
610 		return;
611 
612 	int32 firstIndex = fFirstChange != NULL ? fChanges.IndexOf(fFirstChange) + 1 : 0;
613 	int32 lastIndex = fChanges.IndexOf(fLastChange);
614 
615 	if (fChangesFromSaved >= 0) {
616 		// ascend changes
617 		TRACE(("ApplyChanges(): ascend from %ld to %ld\n", firstIndex, lastIndex));
618 
619 		for (int32 i = firstIndex; i <= lastIndex; i++) {
620 			DataChange *change = fChanges.ItemAt(i);
621 			change->Apply(fRealViewOffset, fView, fRealViewSize);
622 		}
623 	} else {
624 		// descend changes
625 		TRACE(("ApplyChanges(): descend from %ld to %ld\n", firstIndex - 1, lastIndex));
626 
627 		for (int32 i = firstIndex - 1; i > lastIndex; i--) {
628 			DataChange *change = fChanges.ItemAt(i);
629 			change->Revert(fRealViewOffset, fView, fRealViewSize);
630 		}
631 	}
632 }
633 
634 
635 status_t
636 DataEditor::Save()
637 {
638 	BAutolock locker(this);
639 
640 	if (!IsModified())
641 		return B_OK;
642 
643 	StateWatcher watcher(*this);
644 
645 	// Do we need to ascend or descend the list of changes?
646 
647 	int32 firstIndex = fFirstChange != NULL ? fChanges.IndexOf(fFirstChange) + 1 : 0;
648 	int32 lastIndex = fChanges.IndexOf(fLastChange);
649 	if (fChangesFromSaved < 0 && firstIndex != lastIndex) {
650 		// swap indices
651 		ASSERT(firstIndex > lastIndex);
652 
653 		int32 temp = firstIndex - 1;
654 		firstIndex = lastIndex;
655 		lastIndex = temp;
656 	}
657 
658 	if (firstIndex < 0)
659 		firstIndex = 0;
660 	if (lastIndex > fChanges.CountItems() - 1)
661 		lastIndex = fChanges.CountItems();
662 
663 	// Collect ranges of data we need to write.
664 
665 	// ToDo: This is a very simple implementation and could be drastically
666 	// improved by having items that save ranges, not just offsets. If Insert()
667 	// and Remove() are going to be implemented, it should be improved that
668 	// way to reduce the memory footprint to something acceptable.
669 
670 	BObjectList<off_t> list;
671 	for (int32 i = firstIndex; i <= lastIndex; i++) {
672 		DataChange *change = fChanges.ItemAt(i);
673 
674 		off_t offset, size;
675 		change->GetRange(FileSize(), offset, size);
676 		offset -= offset % BlockSize();
677 
678 		while (size > 0) {
679 			list.BinaryInsertCopyUnique(offset, CompareOffsets);
680 			offset += BlockSize();
681 			size -= BlockSize();
682 		}
683 	}
684 
685 	// read in data and apply changes, write it back to disk
686 
687 	off_t oldOffset = fViewOffset;
688 
689 	for (int32 i = 0; i < list.CountItems(); i++) {
690 		off_t offset = *list.ItemAt(i);
691 
692 		// load the data into our view
693 		SetViewOffset(offset, false);
694 
695 		if (fNeedsUpdate) {
696 			status_t status = Update();
697 			if (status < B_OK)
698 				return status;
699 		}
700 
701 		// save back to disk
702 
703 		// don't try to change the file size
704 		size_t size = fRealViewSize;
705 		if (fRealViewOffset + fRealViewSize > fSize)
706 			size = fSize - fRealViewOffset;
707 
708 		ssize_t bytesWritten;
709 		if (IsAttribute())
710 			bytesWritten = fFile.WriteAttr(fAttribute, fType, fRealViewOffset, fView, size);
711 		else
712 			bytesWritten = fFile.WriteAt(fRealViewOffset, fView, size);
713 
714 		if (bytesWritten < B_OK)
715 			return bytesWritten;
716 	}
717 
718 	// update state
719 
720 	SetViewOffset(oldOffset, false);
721 	if (fNeedsUpdate)
722 		Update();
723 
724 	fChangesFromSaved = 0;
725 	fFirstChange = fLastChange;
726 
727 	return B_OK;
728 }
729 
730 
731 /** This method will be called by DataEditor::AddChange()
732  *	immediately before a change is applied.
733  *	It removes all pending redo nodes from the list that would
734  *	come after the current change.
735  */
736 
737 void
738 DataEditor::RemoveRedos()
739 {
740 	int32 start = fChanges.IndexOf(fLastChange) + 1;
741 
742 	for (int32 i = fChanges.CountItems(); i-- > start; ) {
743 		DataChange *change = fChanges.RemoveItemAt(i);
744 		delete change;
745 	}
746 }
747 
748 
749 status_t
750 DataEditor::Undo()
751 {
752 	BAutolock locker(this);
753 
754 	if (!CanUndo())
755 		return B_ERROR;
756 
757 	StateWatcher watcher(*this);
758 		// update state observers
759 
760 	DataChange *undoChange = fLastChange;
761 
762 	int32 index = fChanges.IndexOf(undoChange);
763 	fChangesFromSaved--;
764 	undoChange->Revert(fRealViewOffset, fView, fRealViewSize);
765 
766 	if (index > 0)
767 		fLastChange = fChanges.ItemAt(index - 1);
768 	else
769 		fLastChange = NULL;
770 
771 	// update observers
772 	SendNotices(undoChange);
773 
774 	return B_OK;
775 }
776 
777 
778 status_t
779 DataEditor::Redo()
780 {
781 	BAutolock locker(this);
782 
783 	if (!CanRedo())
784 		return B_ERROR;
785 
786 	StateWatcher watcher(*this);
787 		// update state observers
788 
789 	int32 index = fChanges.IndexOf(fLastChange);
790 	fLastChange = fChanges.ItemAt(index + 1);
791 	fChangesFromSaved++;
792 
793 	fLastChange->Apply(fRealViewOffset, fView, fRealViewSize);
794 
795 	// update observers
796 	SendNotices(fLastChange);
797 
798 	return B_OK;
799 }
800 
801 
802 bool
803 DataEditor::CanUndo() const
804 {
805 	return fLastChange != NULL;
806 }
807 
808 
809 bool
810 DataEditor::CanRedo() const
811 {
812 	return fChanges.IndexOf(fLastChange) < fChanges.CountItems() - 1;
813 }
814 
815 
816 status_t
817 DataEditor::SetFileSize(off_t size)
818 {
819 	// ToDo: implement me!
820 	//fSize = size;
821 	//return B_OK;
822 	return B_ERROR;
823 }
824 
825 
826 status_t
827 DataEditor::SetViewOffset(off_t offset, bool sendNotices)
828 {
829 	BAutolock locker(this);
830 
831 	if (fView == NULL) {
832 		status_t status = SetViewSize(fViewSize);
833 		if (status < B_OK)
834 			return status;
835 	}
836 
837 	if (offset < 0 || offset > fSize)
838 		return B_BAD_VALUE;
839 
840 	offset = (offset / fViewSize) * fViewSize;
841 	if (offset == fViewOffset)
842 		return B_OK;
843 
844 	fViewOffset = offset;
845 	fRealViewOffset = (fViewOffset / fBlockSize) * fBlockSize;
846 	fNeedsUpdate = true;
847 
848 	if (sendNotices) {
849 		BMessage update;
850 		update.AddInt64("offset", fViewOffset);
851 		SendNotices(kMsgDataEditorParameterChange, &update);
852 	}
853 
854 	return B_OK;
855 }
856 
857 
858 status_t
859 DataEditor::SetViewOffset(off_t offset)
860 {
861 	return SetViewOffset(offset, true);
862 }
863 
864 
865 status_t
866 DataEditor::SetViewSize(size_t size, bool sendNotices)
867 {
868 	BAutolock locker(this);
869 
870 	size_t realSize = (size + fBlockSize - 1) & ~(fBlockSize - 1);
871 		// round to the next multiple of block size
872 
873 	if (realSize == fRealViewSize && fViewSize == size && fView != NULL)
874 		return B_OK;
875 
876 	if (realSize == 0)
877 		return B_BAD_VALUE;
878 
879 	if (realSize != fRealViewSize || fView == NULL) {
880 		uint8 *view = (uint8 *)realloc(fView, realSize);
881 		if (view == NULL)
882 			return B_NO_MEMORY;
883 
884 		fView = view;
885 		fRealViewSize = realSize;
886 	}
887 
888 	fViewSize = size;
889 	fNeedsUpdate = true;
890 
891 	// let's correct the view offset if necessary
892 	if (fViewOffset % size)
893 		SetViewOffset(fViewOffset);
894 
895 	if (sendNotices) {
896 		BMessage update;
897 		update.AddInt32("view_size", size);
898 		SendNotices(kMsgDataEditorParameterChange, &update);
899 	}
900 
901 	return B_OK;
902 }
903 
904 
905 status_t
906 DataEditor::SetViewSize(size_t size)
907 {
908 	return SetViewSize(size, true);
909 }
910 
911 
912 status_t
913 DataEditor::SetBlockSize(size_t size)
914 {
915 	BAutolock locker(this);
916 
917 	fBlockSize = size;
918 	status_t status = SetViewOffset(fViewOffset, false);
919 		// this will trigger an update of the real view offset
920 	if (status == B_OK)
921 		status = SetViewSize(fViewSize, false);
922 
923 	BMessage update;
924 	update.AddInt32("block_size", size);
925 	update.AddInt64("offset", fViewOffset);
926 	SendNotices(kMsgDataEditorParameterChange, &update);
927 
928 	return status;
929 }
930 
931 
932 status_t
933 DataEditor::Update()
934 {
935 	ssize_t bytesRead;
936 	if (IsAttribute()) {
937 		BNode node(&fAttributeRef);
938 		bytesRead = node.ReadAttr(fAttribute, fType, fRealViewOffset, fView, fRealViewSize);
939 	} else
940 		bytesRead = fFile.ReadAt(fRealViewOffset, fView, fRealViewSize);
941 
942 	if (bytesRead < B_OK)
943 		return bytesRead;
944 
945 	if ((size_t)bytesRead < fRealViewSize) {
946 		// make sure the rest of data is cleared
947 		memset(fView + bytesRead, 0, fRealViewSize - bytesRead);
948 	}
949 
950 	ApplyChanges();
951 	fNeedsUpdate = false;
952 
953 	return B_OK;
954 }
955 
956 
957 status_t
958 DataEditor::UpdateIfNeeded(bool *_updated)
959 {
960 	if (!fNeedsUpdate) {
961 		if (_updated)
962 			*_updated = false;
963 		return B_OK;
964 	}
965 
966 	status_t status = B_OK;
967 
968 	if (fView == NULL)
969 		status = SetViewOffset(fViewOffset);
970 
971 	if (status == B_OK && fNeedsUpdate) {
972 		status = Update();
973 		if (status == B_OK && _updated)
974 			*_updated = true;
975 	}
976 
977 	return status;
978 }
979 
980 
981 status_t
982 DataEditor::ForceUpdate()
983 {
984 	BAutolock locker(this);
985 
986 	status_t status = B_OK;
987 
988 	off_t newSize = fSize;
989 	if (IsAttribute()) {
990 		// update attribute size (we ignore the type for now)
991 		attr_info info;
992 		status = fFile.GetAttrInfo(fAttribute, &info);
993 		if (status != B_OK) {
994 			// The attribute may have just been removed before
995 			// it gets rewritten, so we don't do anything
996 			// else here (we just set the file size to 0)
997 			newSize = 0;
998 		} else
999 			newSize = info.size;
1000 	} else if (!IsDevice()) {
1001 		// update file size
1002 
1003 		if (fFile.GetSize(&newSize) != B_OK)
1004 			return B_ERROR;
1005 	}
1006 
1007 	if (fSize != newSize) {
1008 		fSize = newSize;
1009 
1010 		// update observers
1011 		BMessage update;
1012 		update.AddInt64("file_size", newSize);
1013 		SendNotices(kMsgDataEditorParameterChange, &update);
1014 	}
1015 
1016 	if (fView == NULL)
1017 		status = SetViewOffset(fViewOffset);
1018 	else {
1019 		BMessage update;
1020 		update.AddInt64("offset", fViewOffset);
1021 		update.AddInt64("size", fViewSize);
1022 		SendNotices(kMsgDataEditorUpdate, &update);
1023 	}
1024 
1025 	if (status == B_OK)
1026 		status = Update();
1027 
1028 	return status;
1029 }
1030 
1031 
1032 status_t
1033 DataEditor::GetViewBuffer(const uint8 **_buffer)
1034 {
1035 	if (!IsLocked())
1036 		debugger("DataEditor: view not locked");
1037 
1038 	status_t status = UpdateIfNeeded();
1039 	if (status < B_OK)
1040 		return status;
1041 
1042 	*_buffer = fView + fViewOffset - fRealViewOffset;
1043 	return B_OK;
1044 }
1045 
1046 
1047 off_t
1048 DataEditor::Find(off_t startPosition, const uint8 *data, size_t dataSize,
1049 	bool caseInsensitive, bool cyclic, BMessenger progressMonitor,
1050 	volatile bool *stop)
1051 {
1052 	if (data == NULL || dataSize == 0)
1053 		return B_BAD_VALUE;
1054 
1055 	if (startPosition < 0)
1056 		startPosition = 0;
1057 
1058 	BAutolock locker(this);
1059 
1060 	typedef int (*compare_func)(const uint8 *a, const uint8 *b, size_t size);
1061 	compare_func compareFunc;
1062 	if (caseInsensitive)
1063 		compareFunc = CompareCaseInsensitive;
1064 	else
1065 		compareFunc = (compare_func)memcmp;
1066 
1067 	bool savedIsReadOnly = fIsReadOnly;
1068 	fIsReadOnly = true;
1069 	off_t savedOffset = fViewOffset;
1070 	off_t position = (startPosition / fRealViewSize) * fRealViewSize;
1071 	size_t firstByte = startPosition % fRealViewSize;
1072 	size_t matchLastOffset = 0;
1073 	off_t foundAt = B_ENTRY_NOT_FOUND;
1074 	bool noStop = false;
1075 	if (stop == NULL)
1076 		stop = &noStop;
1077 
1078 	// start progress monitor
1079 	{
1080 		BMessage progress(kMsgDataEditorFindProgress);
1081 		progress.AddBool("running", true);
1082 		progressMonitor.SendMessage(&progress);
1083 	}
1084 
1085 	bigtime_t lastReport = 0;
1086 
1087 	off_t blocks = fSize;
1088 	if (!cyclic)
1089 		blocks -= position;
1090 	blocks = (blocks + fRealViewSize - 1) / fRealViewSize;
1091 
1092 	for (; blocks-- > 0 && !*stop; position += fRealViewSize) {
1093 		if (position > fSize)
1094 			position = 0;
1095 
1096 		SetViewOffset(position, false);
1097 		if (fNeedsUpdate)
1098 			Update();
1099 
1100 		bigtime_t current = system_time();
1101 		if (lastReport + 500000LL < current) {
1102 			// report the progress two times a second
1103 			BMessage progress(kMsgDataEditorFindProgress);
1104 			progress.AddInt64("position", position);
1105 			progressMonitor.SendMessage(&progress);
1106 
1107 			lastReport = current;
1108 		}
1109 
1110 		// search for data in current block
1111 
1112 		if (matchLastOffset != 0) {
1113 			// we had a partial match in the previous block, let's
1114 			// check if it is a whole match
1115 			if (!compareFunc(fView, data + matchLastOffset, dataSize - matchLastOffset)) {
1116 				matchLastOffset = 0;
1117 				break;
1118 			}
1119 
1120 			foundAt = B_ENTRY_NOT_FOUND;
1121 			matchLastOffset = 0;
1122 		}
1123 
1124 		for (size_t i = firstByte; i < fRealViewSize; i++) {
1125 			if (position + i + dataSize > fSize)
1126 				break;
1127 
1128 			if (!compareFunc(fView + i, data, 1)) {
1129 				// one byte matches, compare the rest
1130 				size_t size = dataSize - 1;
1131 				size_t offset = i + 1;
1132 
1133 				if (offset + size > fRealViewSize)
1134 					size = fRealViewSize - offset;
1135 
1136 				if (size == 0 || !compareFunc(fView + offset, data + 1, size)) {
1137 					foundAt = position + i;
1138 
1139 					if (size != dataSize - 1) {
1140 						// only a partial match, we have to check the start
1141 						// of the next block
1142 						matchLastOffset = size + 1;
1143 					}
1144 					break;
1145 				}
1146 			}
1147 		}
1148 
1149 		if (foundAt >= 0 && matchLastOffset == 0)
1150 			break;
1151 
1152 		firstByte = 0;
1153 	}
1154 
1155 	fIsReadOnly = savedIsReadOnly;
1156 
1157 	if (foundAt >= 0 && matchLastOffset != 0)
1158 		foundAt = B_ENTRY_NOT_FOUND;
1159 
1160 	// stop progress monitor
1161 	{
1162 		BMessage progress(kMsgDataEditorFindProgress);
1163 		progress.AddBool("running", false);
1164 		progress.AddInt64("position", foundAt >= 0 ? foundAt : savedOffset);
1165 		progressMonitor.SendMessage(&progress);
1166 	}
1167 
1168 	SetViewOffset(savedOffset, false);
1169 		// this is to ensure that we're sending an update when
1170 		// we're set to the found data offset
1171 
1172 	if (foundAt < 0 && *stop)
1173 		return B_INTERRUPTED;
1174 
1175 	return foundAt;
1176 }
1177 
1178 
1179 void
1180 DataEditor::SendNotices(DataChange *change)
1181 {
1182 	off_t offset, size;
1183 	change->GetRange(FileSize(), offset, size);
1184 
1185 	// update observer
1186 	BMessage update;
1187 	update.AddInt64("offset", offset);
1188 	update.AddInt64("size", size);
1189 	SendNotices(kMsgDataEditorUpdate, &update);
1190 }
1191 
1192 
1193 void
1194 DataEditor::SendNotices(uint32 what, BMessage *message)
1195 {
1196 	if (fObservers.CountItems() == 0)
1197 		return;
1198 
1199 	BMessage *notice;
1200 	if (message) {
1201 		notice = new BMessage(*message);
1202 		notice->what = what;
1203 	} else
1204 		notice = new BMessage(what);
1205 
1206 	for (int32 i = fObservers.CountItems(); i-- > 0;) {
1207 		BMessenger *messenger = fObservers.ItemAt(i);
1208 		messenger->SendMessage(notice);
1209 	}
1210 
1211 	delete notice;
1212 }
1213 
1214 
1215 status_t
1216 DataEditor::StartWatching(BMessenger target)
1217 {
1218 	BAutolock locker(this);
1219 
1220 	node_ref node;
1221 	status_t status = fFile.GetNodeRef(&node);
1222 	if (status < B_OK)
1223 		return status;
1224 
1225 	fObservers.AddItem(new BMessenger(target));
1226 
1227 	return watch_node(&node, B_WATCH_STAT | B_WATCH_ATTR, target);
1228 }
1229 
1230 
1231 status_t
1232 DataEditor::StartWatching(BHandler *handler, BLooper *looper)
1233 {
1234 	return StartWatching(BMessenger(handler, looper));
1235 }
1236 
1237 
1238 void
1239 DataEditor::StopWatching(BMessenger target)
1240 {
1241 	BAutolock locker(this);
1242 
1243 	for (int32 i = fObservers.CountItems(); i-- > 0;) {
1244 		BMessenger *messenger = fObservers.ItemAt(i);
1245 		if (*messenger == target) {
1246 			fObservers.RemoveItemAt(i);
1247 			delete messenger;
1248 			break;
1249 		}
1250 	}
1251 
1252 	stop_watching(target);
1253 }
1254 
1255 
1256 void
1257 DataEditor::StopWatching(BHandler *handler, BLooper *looper)
1258 {
1259 	StopWatching(BMessenger(handler, looper));
1260 }
1261 
1262