DNDArrayController.m

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 */



#import "DNDArrayController.h"
#import "MyDocument.h"


NSString *MovedRowsType = @"MOVED_ROWS_TYPE";


/*
 Utility method to retrieve the number of indexes in a given range
 */
@interface NSIndexSet (CountOfIndexesInRange)
-(unsigned int)countOfIndexesInRange:(NSRange)range;
@end



@implementation DNDArrayController



- (void)awakeFromNib
{
    // register for drag and drop
    
	[tableView setDraggingSourceOperationMask:NSDragOperationLink forLocal:NO];
	[tableView setDraggingSourceOperationMask:(NSDragOperationCopy | NSDragOperationMove) forLocal:YES];
	
	[tableView registerForDraggedTypes:
	 [NSArray arrayWithObjects:CopiedRowsType, MovedRowsType, NSURLPboardType, nil]];
    [tableView setAllowsMultipleSelection:YES];
	
	[super awakeFromNib];
}



- (BOOL)tableView:(NSTableView *)aTableView
writeRowsWithIndexes:(NSIndexSet *)rowIndexes
	 toPasteboard:(NSPasteboard *)pboard
{
	// declare our own pasteboard types
    NSArray *typesArray = [NSArray arrayWithObjects:CopiedRowsType, MovedRowsType, nil];
	
	/*
	 If the number of rows is not 1, then we only support our own types.
	 If there is just one row, then try to create an NSURL from the url
	 value in that row.  If that's possible, add NSURLPboardType to the
	 list of supported types, and add the NSURL to the pasteboard.
	 */
	if ([rowIndexes count] != 1)
	{
		[pboard declareTypes:typesArray owner:self];
	}
	else
	{
		// Try to create an URL
		// If we can, add NSURLPboardType to the declared types and write
		//the URL to the pasteboard; otherwise declare existing types
		unsigned int row = [rowIndexes firstIndex];
		NSString *urlString = [[[self arrangedObjects] objectAtIndex:row] valueForKey:@"url"];
		NSURL *url;
		
		if (urlString && (url = [NSURL URLWithString:urlString]))
		{
			typesArray = [typesArray arrayByAddingObject:NSURLPboardType];	
			[pboard declareTypes:typesArray owner:self];
			[url writeToPasteboard:pboard];	
		}
		else
		{
			[pboard declareTypes:typesArray owner:self];
		}
	}
	
    // add rows array for local move
	NSData *rowIndexesArchive = [NSKeyedArchiver archivedDataWithRootObject:rowIndexes];
    [pboard setData:rowIndexesArchive forType:MovedRowsType];
	
	// create new array of selected rows for remote drop
    // could do deferred provision, but keep it direct for clarity
	NSMutableArray *rowCopies = [NSMutableArray arrayWithCapacity:[rowIndexes count]];
	
    unsigned int currentIndex = [rowIndexes firstIndex];
    while (currentIndex != NSNotFound)
    {
		[rowCopies addObject:[[self arrangedObjects] objectAtIndex:currentIndex]];
        currentIndex = [rowIndexes indexGreaterThanIndex: currentIndex];
    }
	
	// setPropertyList works here because we're using dictionaries, strings,
	// and dates; otherwise, archive collection to NSData...
	[pboard setPropertyList:rowCopies forType:CopiedRowsType];
	
    return YES;
}


- (NSDragOperation)tableView:(NSTableView*)tv
				validateDrop:(id <NSDraggingInfo>)info
				 proposedRow:(int)row
	   proposedDropOperation:(NSTableViewDropOperation)op
{
    
    NSDragOperation dragOp = NSDragOperationCopy;
    
    // if drag source is self, it's a move unless the Option key is pressed
    if ([info draggingSource] == tableView) {
		
		NSEvent *currentEvent = [NSApp currentEvent];
		int optionKeyPressed = [currentEvent modifierFlags] & NSAlternateKeyMask;
		if (optionKeyPressed == 0) {
			dragOp =  NSDragOperationMove;
		}
    }
    // we want to put the object at, not over,
    // the current row (contrast NSTableViewDropOn) 
    [tv setDropRow:row dropOperation:NSTableViewDropAbove];
	
    return dragOp;
}



- (BOOL)tableView:(NSTableView*)tv
	   acceptDrop:(id <NSDraggingInfo>)info
			  row:(int)row
	dropOperation:(NSTableViewDropOperation)op
{
    if (row < 0) {
		row = 0;
	}
	// if drag source is self, it's a move unless the Option key is pressed
    if ([info draggingSource] == tableView) {
		
		NSEvent *currentEvent = [NSApp currentEvent];
		int optionKeyPressed = [currentEvent modifierFlags] & NSAlternateKeyMask;
		
		if (optionKeyPressed == 0) {
			
			NSData *rowsData = [[info draggingPasteboard] dataForType:MovedRowsType];
			NSIndexSet *indexSet = [NSKeyedUnarchiver unarchiveObjectWithData:rowsData];
			
			NSIndexSet *destinationIndexes = [self moveObjectsInArrangedObjectsFromIndexes:indexSet toIndex:row];
			// set selected rows to those that were just moved
			[self setSelectionIndexes:destinationIndexes];
			
			return YES;
		}
    }
	
	// Can we get rows from another document?  If so, add them, then return.
	NSArray *newRows = [[info draggingPasteboard] propertyListForType:CopiedRowsType];
	
	if (newRows) {
		NSRange range = NSMakeRange(row, [newRows count]);
		NSIndexSet *indexSet = [NSIndexSet indexSetWithIndexesInRange:range];
		
		[self insertObjects:newRows atArrangedObjectIndexes:indexSet];
		// set selected rows to those that were just copied
		[self setSelectionIndexes:indexSet];
		return YES;
    }
	
	// Can we get an URL?  If so, add a new row, configure it, then return.
	NSURL *url = [NSURL URLFromPasteboard:[info draggingPasteboard]];
	
	if (url) {
		id newObject = [self newObject];	
		[self insertObject:newObject atArrangedObjectIndex:row];
		// "new" -- returned with retain count of 1
		[newObject release];
		[newObject takeValue:[url absoluteString] forKey:@"url"];
		[newObject takeValue:[NSCalendarDate date] forKey:@"date"];
		// set selected rows to those that were just copied
		[self setSelectionIndex:row];
		return YES;		
	}
    return NO;
}



-(NSIndexSet *) moveObjectsInArrangedObjectsFromIndexes:(NSIndexSet*)fromIndexSet
												toIndex:(unsigned int)insertIndex
{	
	// If any of the removed objects come before the insertion index,
	// we need to decrement the index appropriately
	unsigned int adjustedInsertIndex =
	insertIndex - [fromIndexSet countOfIndexesInRange:(NSRange){0, insertIndex}];
	NSRange destinationRange = NSMakeRange(adjustedInsertIndex, [fromIndexSet count]);
	NSIndexSet *destinationIndexes = [NSIndexSet indexSetWithIndexesInRange:destinationRange];
	
	NSArray *objectsToMove = [[self arrangedObjects] objectsAtIndexes:fromIndexSet];
	[self removeObjectsAtArrangedObjectIndexes:fromIndexSet];	
	[self insertObjects:objectsToMove atArrangedObjectIndexes:destinationIndexes];
	
	return destinationIndexes;
}



@end



/*
 Implementation of NSIndexSet utility category
 */
@implementation NSIndexSet (CountOfIndexesInRange)

-(unsigned int)countOfIndexesInRange:(NSRange)range
{
	unsigned int start, end, count;
	
	if ((start == 0) && (range.length == 0))
	{
		return 0;	
	}
	
	start	= range.location;
	end		= start + range.length;
	count	= 0;
	
	unsigned int currentIndex = [self indexGreaterThanOrEqualToIndex:start];
	
	while ((currentIndex != NSNotFound) && (currentIndex < end))
	{
		count++;
		currentIndex = [self indexGreaterThanIndex:currentIndex];
	}
	
	return count;
}
@end