src/INDSequentialTextSelectionManager.mm - ring-client-macosx - Gitiles

 //
 //  INDSequentialTextSelectionManager.m
 //  INDSequentialTextSelectionManager
 //
 //  Created by Indragie Karunaratne on 2014-03-02.
 //  Copyright (c) 2014 Indragie Karunaratne. All rights reserved.
 //

 #import "INDSequentialTextSelectionManager.h"
 #import <objc/runtime.h>

 static NSUInteger INDCharacterIndexForTextViewEvent(NSEvent *event, NSTextView *textView)
 {
     NSView *contentView = event.window.contentView;
     NSPoint point = [contentView convertPoint:event.locationInWindow fromView:nil];
     NSPoint textPoint = [textView convertPoint:point fromView:contentView];
     return [textView characterIndexForInsertionAtPoint:textPoint];
 }

 static NSRange INDForwardRangeForIndices(NSUInteger idx1, NSUInteger idx2) {
     NSRange range;
     if (idx2 >= idx1) {
         range = NSMakeRange(idx1, idx2 - idx1);
     } else if (idx2 < idx1) {
         range = NSMakeRange(idx2, idx1 - idx2);
     } else {
         range = NSMakeRange(NSNotFound, 0);
     }
     return range;
 }

 static void * INDUniqueIdentifierKey = &INDUniqueIdentifierKey;

 @interface NSTextView (INDUniqueIdentifiers)
 @property (nonatomic, copy) NSString *ind_uniqueIdentifier;
 @end

 @implementation NSTextView (INDUniqueIdentifiers)

 - (void)setInd_uniqueIdentifier:(NSString *)ind_uniqueIdentifier
 {
     objc_setAssociatedObject(self, INDUniqueIdentifierKey, ind_uniqueIdentifier, OBJC_ASSOCIATION_COPY_NONATOMIC);
 }

 - (NSString *)ind_uniqueIdentifier
 {
     return objc_getAssociatedObject(self, INDUniqueIdentifierKey);
 }

 @end

 @interface INDAttributeRange : NSObject
 @property (nonatomic, copy, readonly) NSString *attribute;
 @property (nonatomic, strong, readonly) id value;
 @property (nonatomic, assign, readonly) NSRange range;
 - (id)initWithAttribute:(NSString *)attribute value:(id)value range:(NSRange)range;
 @end

 @implementation INDAttributeRange

 - (id)initWithAttribute:(NSString *)attribute value:(id)value range:(NSRange)range
 {
     if ((self = [super init])) {
         _attribute = [attribute copy];
         _value = value;
         _range = range;
     }
     return self;
 }

 @end

 static void * INDBackgroundColorRangesKey = &INDBackgroundColorRangesKey;
 static void * INDHighlightedRangeKey = &INDHighlightedRangeKey;

 #define IND_DISABLED_SELECTED_TEXT_BG_COLOR [NSColor colorWithDeviceRed:0.83 green:0.83 blue:0.83 alpha:1.0]

 @interface NSTextView (INDSelectionHighlight)
 @property (nonatomic, strong) NSArray *ind_backgroundColorRanges;
 @property (nonatomic, assign) NSRange ind_highlightedRange;
 @end

 @implementation NSTextView (INDSelectionHighlight)

 - (void)ind_highlightSelectedTextInRange:(NSRange)range drawActive:(BOOL)active
 {
     if (self.ind_backgroundColorRanges == nil) {
         [self ind_backupBackgroundColorState];
     }
     self.ind_highlightedRange = range;

     NSColor *selectedColor = nil;
     if (active) {
         selectedColor = self.selectedTextAttributes[NSBackgroundColorAttributeName] ?: NSColor.selectedTextBackgroundColor;
     } else {
         selectedColor = IND_DISABLED_SELECTED_TEXT_BG_COLOR;
     }
     [self.textStorage beginEditing];
     [self.textStorage removeAttribute:NSBackgroundColorAttributeName range:NSMakeRange(0, self.textStorage.length)];
     [self.textStorage addAttribute:NSBackgroundColorAttributeName value:selectedColor range:range];
     [self.textStorage endEditing];
     [self setNeedsDisplay:YES];
 }

 - (void)ind_backupBackgroundColorState
 {
     NSMutableArray *ranges = [NSMutableArray array];
     NSString *attribute = NSBackgroundColorAttributeName;
     [self.textStorage enumerateAttribute:attribute inRange:NSMakeRange(0, self.textStorage.length) options:0 usingBlock:^(id value, NSRange range, BOOL *stop) {
         if (value == nil) return;
         INDAttributeRange *attrRange = [[INDAttributeRange alloc] initWithAttribute:attribute value:value range:range];
         [ranges addObject:attrRange];
     }];
     self.ind_backgroundColorRanges = ranges;
 }

 - (void)ind_deselectHighlightedText
 {
     [self.textStorage beginEditing];
     [self.textStorage removeAttribute:NSBackgroundColorAttributeName range:NSMakeRange(0, self.string.length)];
     NSArray *ranges = self.ind_backgroundColorRanges;
     for (INDAttributeRange *range in ranges) {
         [self.textStorage addAttribute:range.attribute value:range.value range:range.range];
     }
     [self.textStorage endEditing];
     [self setNeedsDisplay:YES];

     self.ind_backgroundColorRanges = nil;
     self.ind_highlightedRange = NSMakeRange(0, 0);
 }

 - (void)setInd_backgroundColorRanges:(NSArray *)ind_backgroundColorRanges
 {
     objc_setAssociatedObject(self, INDBackgroundColorRangesKey, ind_backgroundColorRanges, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
 }

 - (NSArray *)ind_backgroundColorRanges
 {
     return objc_getAssociatedObject(self, INDBackgroundColorRangesKey);
 }

 - (void)setInd_highlightedRange:(NSRange)ind_highlightedRange
 {
     objc_setAssociatedObject(self, INDHighlightedRangeKey, [NSValue valueWithRange:ind_highlightedRange], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
 }

 - (NSRange)ind_highlightedRange
 {
     return [objc_getAssociatedObject(self, INDHighlightedRangeKey) rangeValue];
 }

 @end

 @interface INDTextViewSelectionRange : NSObject
 @property (nonatomic, copy, readonly) NSString *textViewIdentifier;
 @property (nonatomic, assign, readonly) NSRange range;
 @property (nonatomic, copy, readonly) NSAttributedString *attributedText;
 - (id)initWithTextView:(NSTextView *)textView selectedRange:(NSRange)range;
 @end

 @implementation INDTextViewSelectionRange

 - (id)initWithTextView:(NSTextView *)textView selectedRange:(NSRange)range
 {
     if ((self = [super init])) {
         _textViewIdentifier = [textView.ind_uniqueIdentifier copy];
         _range = range;
         _attributedText = [[textView.attributedString attributedSubstringFromRange:range] copy];
     }
     return self;
 }

 @end

 @interface INDTextViewSelectionSession : NSObject
 @property (nonatomic, copy, readonly) NSString *textViewIdentifier;
 @property (nonatomic, assign, readonly) NSUInteger characterIndex;
 @property (nonatomic, strong, readonly) NSDictionary *selectionRanges;
 @property (nonatomic, assign) NSPoint windowPoint;
 - (void)addSelectionRange:(INDTextViewSelectionRange *)range;
 - (void)removeSelectionRangeForTextView:(NSTextView *)textView;
 @end

 @implementation INDTextViewSelectionSession {
     NSMutableDictionary *_selectionRanges;
 }
 @synthesize selectionRanges = _selectionRanges;

 - (id)initWithTextView:(NSTextView *)textView event:(NSEvent *)event
 {
     if ((self = [super init])) {
         _textViewIdentifier = [textView.ind_uniqueIdentifier copy];
         _characterIndex = INDCharacterIndexForTextViewEvent(event, textView);
         _selectionRanges = [NSMutableDictionary dictionary];
         _windowPoint = event.locationInWindow;
     }
     return self;
 }

 - (void)addSelectionRange:(INDTextViewSelectionRange *)range
 {
     NSParameterAssert(range.textViewIdentifier);
     _selectionRanges[range.textViewIdentifier] = range;
 }

 - (void)removeSelectionRangeForTextView:(NSTextView *)textView
 {
     NSParameterAssert(textView.ind_uniqueIdentifier);
     [_selectionRanges removeObjectForKey:textView.ind_uniqueIdentifier];
 }

 @end

 @interface INDTextViewMetadata : NSObject
 @property (nonatomic, strong, readonly) NSTextView *textView;
 @property (nonatomic, copy, readonly) INDAttributedTextTransformationBlock transformationBlock;
 - (id)initWithTextView:(NSTextView *)textView transformationBlock:(INDAttributedTextTransformationBlock)transformationBlock;
 @end

 @implementation INDTextViewMetadata

 - (id)initWithTextView:(NSTextView *)textView transformationBlock:(INDAttributedTextTransformationBlock)transformationBlock
 {
     if ((self = [super init])) {
         _textView = textView;
         _transformationBlock = [transformationBlock copy];
     }
     return self;
 }

 @end

 @interface INDSequentialTextSelectionManager ()
 @property (nonatomic, strong, readonly) NSMutableDictionary *textViews;
 @property (nonatomic, strong, readonly) NSMutableOrderedSet *sortedTextViews;
 @property (nonatomic, strong) INDTextViewSelectionSession *currentSession;
 @property (nonatomic, strong) NSAttributedString *cachedAttributedText;
 @property (nonatomic, strong) id eventMonitor;
 @property (nonatomic, assign, getter = isFirstResponder) BOOL firstResponder;
 @end

 @implementation INDSequentialTextSelectionManager

 #pragma mark - Iniialization

 - (id)init
 {
     if ((self = [super init])) {
         _textViews = [NSMutableDictionary dictionary];
         _sortedTextViews = [NSMutableOrderedSet orderedSet];
         _eventMonitor = [self addLocalEventMonitor];
     }
     return self;
 }

 #pragma mark - Cleanup

 - (void)dealloc
 {
     [NSEvent removeMonitor:_eventMonitor];
 }

 #pragma mark - Events

 - (BOOL)handleLeftMouseDown:(NSEvent *)event
 {
     // Allow for correct handling of double clicks on text views.
     if (event.clickCount == 1) {
         [self endSession];

         NSTextView *textView = [self validTextViewForEvent:event];
         // Ignore if the text view is not "owned" by this manager, or if it is being
         // edited at the time of this event.
         if (textView && textView.window.firstResponder != textView) {
             self.currentSession = [[INDTextViewSelectionSession alloc] initWithTextView:textView event:event];
             return YES;
         }
     }
     return NO;
 }

 - (BOOL)handleLeftMouseUp:(NSEvent *)event
 {
     if (self.currentSession == nil) return NO;

     [event.window makeFirstResponder:self];
     NSTextView *textView = [self validTextViewForEvent:event];
     if (textView != nil) {
         // Handle link clicks properly.
         NSUInteger index = INDCharacterIndexForTextViewEvent(event, textView);
         if (index < textView.string.length) {
             NSDictionary *attributes = [textView.attributedString attributesAtIndex:index effectiveRange:NULL];
             id link = attributes[NSLinkAttributeName];

             // From documentation, NSLinkAttributeName could be either an NSString * or NSURL *
             if (link != nil) {
                 [textView clickedOnLink:link atIndex:index];
             }
         }
     }
     return YES;
 }

 - (BOOL)handleLeftMouseDragged:(NSEvent *)event
 {
     if (self.currentSession == nil) return NO;

     NSTextView *textView = [self validTextViewForEvent:event];
     if (textView != nil) {
         [textView.window makeFirstResponder:textView];
         NSSelectionAffinity affinity = (event.locationInWindow.y < self.currentSession.windowPoint.y) ? NSSelectionAffinityDownstream : NSSelectionAffinityUpstream;
         self.currentSession.windowPoint = event.locationInWindow;

         NSUInteger current;
         NSString *identifier = self.currentSession.textViewIdentifier;
         if ([textView.ind_uniqueIdentifier isEqualTo:identifier]) {
             current = self.currentSession.characterIndex;
         } else {
             INDTextViewMetadata *meta = self.textViews[identifier];
             NSUInteger start = [self.sortedTextViews indexOfObject:meta.textView];
             NSUInteger end = [self.sortedTextViews indexOfObject:textView];
             current = (end >= start) ? 0 : textView.string.length;
         }
         NSUInteger index = INDCharacterIndexForTextViewEvent(event, textView);
         NSRange range = INDForwardRangeForIndices(index, current);
         [self setSelectionRangeForTextView:textView withRange:range];
         [self processCompleteSelectionsForTargetTextView:textView affinity:affinity];
     }
     return YES;
 }

 - (BOOL)handleRightMouseDown:(NSEvent *)event
 {
     if (self.currentSession == nil) return NO;

     [event.window makeFirstResponder:self];
     NSTextView *textView = [self validTextViewForEvent:event];
     if (textView != nil) {
         NSMenu *menu = [self menuForEvent:event];
         [NSMenu popUpContextMenu:menu withEvent:event forView:textView];
     }
     return YES;
 }

 - (id)addLocalEventMonitor
 {
     return [NSEvent addLocalMonitorForEventsMatchingMask:NSLeftMouseDownMask | NSLeftMouseDraggedMask | NSLeftMouseUpMask | NSRightMouseDownMask handler:^NSEvent *(NSEvent *event) {
         switch (event.type) {
             case NSLeftMouseDown:
                 return [self handleLeftMouseDown:event] ? nil : event;
             case NSLeftMouseDragged:
                 return [self handleLeftMouseDragged:event] ? nil : event;
             case NSLeftMouseUp:
                 return [self handleLeftMouseUp:event] ? nil : event;
             case NSRightMouseDown:
                 return [self handleRightMouseDown:event] ? nil : event;
             default:
                 return event;
         }
     }];
 }

 - (NSTextView *)validTextViewForEvent:(NSEvent *)event
 {
     NSView *contentView = event.window.contentView;
     NSPoint point = [contentView convertPoint:event.locationInWindow fromView:nil];
     NSView *view = [contentView hitTest:point];
     if ([view isKindOfClass:NSTextView.class]) {
         NSTextView *textView = (NSTextView *)view;
         NSString *identifier = textView.ind_uniqueIdentifier;
         return (textView.isSelectable && identifier && self.textViews[identifier]) ? textView : nil;
     }
     return nil;
 }

 #pragma mark - NSResponder

 - (NSAttributedString *)cachedAttributedText
 {
     if (_cachedAttributedText == nil) {
         _cachedAttributedText = [self buildAttributedStringForCurrentSession];
     }
     return _cachedAttributedText;
 }

 - (void)copy:(id)sender
 {
     NSPasteboard *pboard = NSPasteboard.generalPasteboard;
     [pboard clearContents];
     [pboard writeObjects:@[self.cachedAttributedText]];
 }

 - (NSMenu *)buildSharingMenu
 {
     NSMenu *shareMenu = [[NSMenu alloc] initWithTitle:NSLocalizedString(@"Share", nil)];
     NSArray *services = [NSSharingService sharingServicesForItems:@[self.cachedAttributedText]];
     for (NSSharingService *service in services) {
         NSMenuItem *item = [shareMenu addItemWithTitle:service.title action:@selector(share:) keyEquivalent:@""];
         item.target = self;
         item.image = service.image;
         item.representedObject = service;
     }
     return shareMenu;
 }

 - (NSMenu *)menuForEvent:(NSEvent *)theEvent
 {
     NSMenu *menu = [[NSMenu alloc] initWithTitle:NSLocalizedString(@"Text Actions", nil)];
     NSMenuItem *copy = [menu addItemWithTitle:NSLocalizedString(@"Copy", nil) action:@selector(copy:) keyEquivalent:@""];
     copy.target = self;
     [menu addItem:NSMenuItem.separatorItem];

     NSMenuItem *share = [menu addItemWithTitle:NSLocalizedString(@"Share", nil) action:nil keyEquivalent:@""];
     share.submenu = [self buildSharingMenu];

     return menu;
 }

 - (void)share:(NSMenuItem *)item
 {
     NSSharingService *service = item.representedObject;
     [service performWithItems:@[self.cachedAttributedText]];
 }

 - (void)rehighlightSelectedRangesAsActive:(BOOL)active
 {
     NSArray *ranges = self.currentSession.selectionRanges.allValues;
     for (INDTextViewSelectionRange *range in ranges) {
         INDTextViewMetadata *meta = self.textViews[range.textViewIdentifier];
         [meta.textView ind_highlightSelectedTextInRange:range.range drawActive:active];
     }
 }

 - (BOOL)resignFirstResponder
 {
     [self rehighlightSelectedRangesAsActive:NO];
     self.firstResponder = NO;
     return YES;
 }

 - (BOOL)becomeFirstResponder
 {
     [self rehighlightSelectedRangesAsActive:YES];
     self.firstResponder = YES;
     return YES;
 }

 #pragma mark - Selection

 - (void)setSelectionRangeForTextView:(NSTextView *)textView withRange:(NSRange)range
 {
     if (range.location == NSNotFound || NSMaxRange(range) == 0) {
         [textView ind_deselectHighlightedText];
         [self.currentSession removeSelectionRangeForTextView:textView];
     } else {
         INDTextViewSelectionRange *selRange = [[INDTextViewSelectionRange alloc] initWithTextView:textView selectedRange:range];
         [self.currentSession addSelectionRange:selRange];
         [textView ind_highlightSelectedTextInRange:range drawActive:YES];
     }
 }

 - (void)processCompleteSelectionsForTargetTextView:(NSTextView *)textView affinity:(NSSelectionAffinity)affinity
 {
     if (self.currentSession == nil) return;

     INDTextViewMetadata *meta = self.textViews[self.currentSession.textViewIdentifier];
     NSUInteger start = [self.sortedTextViews indexOfObject:meta.textView];
     NSUInteger end = [self.sortedTextViews indexOfObject:textView];
     if (start == NSNotFound || end == NSNotFound) return;

     NSRange subrange = NSMakeRange(NSNotFound, 0);
     BOOL select = NO;
     NSUInteger count = self.sortedTextViews.count;
     if (end > start) {
         if (affinity == NSSelectionAffinityDownstream) {
             subrange = NSMakeRange(start, end - start);
             select = YES;
         } else if (count > end + 1) {
             subrange = NSMakeRange(end + 1, count - end - 1);
         }
     } else if (end < start) {
         if (affinity == NSSelectionAffinityUpstream) {
             subrange = NSMakeRange(end + 1, start - end);
             select = YES;
         } else {
             subrange = NSMakeRange(0, end);
         }
     }
     NSArray *subarray = nil;
     if (subrange.location == NSNotFound) {
         NSMutableOrderedSet *views = [self.sortedTextViews mutableCopy];
         [views removeObject:textView];
         subarray = views.array;
     } else {
         subarray = [self.sortedTextViews.array subarrayWithRange:subrange];
     }
     for (NSTextView *tv in subarray) {
         NSRange range;
         if (select) {
             NSRange currentRange = tv.ind_highlightedRange;
             if (affinity == NSSelectionAffinityDownstream) {
                 range = NSMakeRange(currentRange.location, tv.string.length - currentRange.location);
             } else {
                 range = NSMakeRange(0, NSMaxRange(currentRange) ?: tv.string.length);
             }
         } else {
             range = NSMakeRange(0, 0);
         }
         [self setSelectionRangeForTextView:tv withRange:range];
     }
 }

 - (void)endSession
 {
     for (INDTextViewMetadata *meta in self.textViews.allValues) {
         [meta.textView ind_deselectHighlightedText];
     }
     self.currentSession = nil;
     self.cachedAttributedText = nil;
 }

 #pragma mark - Text

 - (NSAttributedString *)buildAttributedStringForCurrentSession
 {
     if (self.currentSession == nil) return nil;

     NSDictionary *ranges = self.currentSession.selectionRanges;
     NSMutableArray *keys = [ranges.allKeys mutableCopy];
     NSComparator textViewComparator = self.textViewComparator;
     [keys sortUsingComparator:^NSComparisonResult(NSString *obj1, NSString *obj2) {
         INDTextViewMetadata *meta1 = self.textViews[obj1];
         INDTextViewMetadata *meta2 = self.textViews[obj2];
         return textViewComparator(meta1.textView, meta2.textView);
     }];
     NSMutableAttributedString *string = [[NSMutableAttributedString alloc] init];
     [string beginEditing];
     [keys enumerateObjectsUsingBlock:^(NSString *key, NSUInteger idx, BOOL *stop) {
         INDTextViewSelectionRange *range = ranges[key];
         INDTextViewMetadata *meta = self.textViews[range.textViewIdentifier];
         NSAttributedString *fragment = range.attributedText;
         if (meta.transformationBlock != nil) {
             fragment = meta.transformationBlock(fragment);
         }
         [string appendAttributedString:fragment];
         if (string.length && idx != keys.count - 1) {
             NSDictionary *attributes = [string attributesAtIndex:string.length - 1 effectiveRange:NULL];
             NSAttributedString *newline = [[NSAttributedString alloc] initWithString:@"\n" attributes:attributes];
             [string appendAttributedString:newline];
         }
     }];
     [string endEditing];
     return string;
 }

 #pragma mark - Registration

 - (void)registerTextView:(NSTextView *)textView withUniqueIdentifier:(NSString *)identifier
 {
     [self registerTextView:textView withUniqueIdentifier:identifier transformationBlock:nil];
 }

 - (void)registerTextView:(NSTextView *)textView withUniqueIdentifier:(NSString *)identifier transformationBlock:(INDAttributedTextTransformationBlock)block
 {
     NSParameterAssert(identifier);
     NSParameterAssert(textView);

     [self unregisterTextView:textView];
     textView.ind_uniqueIdentifier = identifier;
     if (self.currentSession) {
         INDTextViewSelectionRange *range = self.currentSession.selectionRanges[identifier];
         if (range) {
             [textView ind_highlightSelectedTextInRange:range.range drawActive:self.firstResponder];
         }
     }
     self.textViews[identifier] = [[INDTextViewMetadata alloc] initWithTextView:textView transformationBlock:block];

     [self.sortedTextViews addObject:textView];
     [self sortTextViews];
 }

 - (NSComparator)textViewComparator
 {
     return ^NSComparisonResult(NSTextView *obj1, NSTextView *obj2) {
         // Convert to window coordinates to normalize coordinate flipped-ness
         NSRect frame1 = [obj1 convertRect:obj1.bounds toView:nil];
         NSRect frame2 = [obj2 convertRect:obj2.bounds toView:nil];

         CGFloat y1 = NSMinY(frame1);
         CGFloat y2 = NSMinY(frame2);

         if (y1 > y2) {
             return NSOrderedAscending;
         } else if (y1 < y2) {
             return NSOrderedDescending;
         } else {
             return NSOrderedSame;
         }
     };
 }

 - (void)sortTextViews
 {
     [self.sortedTextViews sortUsingComparator:self.textViewComparator];
 }

 - (void)unregisterTextView:(NSTextView *)textView
 {
     if (textView.ind_uniqueIdentifier == nil) return;
     [self.textViews removeObjectForKey:textView.ind_uniqueIdentifier];
     [self.sortedTextViews removeObject:textView];
     [self sortTextViews];

     textView.ind_uniqueIdentifier = nil;
 }

 - (void)unregisterAllTextViews
 {
     [self.textViews removeAllObjects];
     [self.sortedTextViews removeAllObjects];
 }

 @end
	//
	// INDSequentialTextSelectionManager.m
	// INDSequentialTextSelectionManager
	//
	// Created by Indragie Karunaratne on 2014-03-02.
	// Copyright (c) 2014 Indragie Karunaratne. All rights reserved.
	//

	#import "INDSequentialTextSelectionManager.h"
	#import <objc/runtime.h>

	static NSUInteger INDCharacterIndexForTextViewEvent(NSEvent event, NSTextView textView)
	{
	NSView *contentView = event.window.contentView;
	NSPoint point = [contentView convertPoint:event.locationInWindow fromView:nil];
	NSPoint textPoint = [textView convertPoint:point fromView:contentView];
	return [textView characterIndexForInsertionAtPoint:textPoint];
	}

	static NSRange INDForwardRangeForIndices(NSUInteger idx1, NSUInteger idx2) {
	NSRange range;
	if (idx2 >= idx1) {
	range = NSMakeRange(idx1, idx2 - idx1);
	} else if (idx2 < idx1) {
	range = NSMakeRange(idx2, idx1 - idx2);
	} else {
	range = NSMakeRange(NSNotFound, 0);
	}
	return range;
	}

	static void * INDUniqueIdentifierKey = &INDUniqueIdentifierKey;

	@interface NSTextView (INDUniqueIdentifiers)
	@property (nonatomic, copy) NSString *ind_uniqueIdentifier;
	@end

	@implementation NSTextView (INDUniqueIdentifiers)

	- (void)setInd_uniqueIdentifier:(NSString *)ind_uniqueIdentifier
	{
	objc_setAssociatedObject(self, INDUniqueIdentifierKey, ind_uniqueIdentifier, OBJC_ASSOCIATION_COPY_NONATOMIC);
	}

	- (NSString *)ind_uniqueIdentifier
	{
	return objc_getAssociatedObject(self, INDUniqueIdentifierKey);
	}

	@end

	@interface INDAttributeRange : NSObject
	@property (nonatomic, copy, readonly) NSString *attribute;
	@property (nonatomic, strong, readonly) id value;
	@property (nonatomic, assign, readonly) NSRange range;
	- (id)initWithAttribute:(NSString *)attribute value:(id)value range:(NSRange)range;
	@end

	@implementation INDAttributeRange

	- (id)initWithAttribute:(NSString *)attribute value:(id)value range:(NSRange)range
	{
	if ((self = [super init])) {
	_attribute = [attribute copy];
	_value = value;
	_range = range;
	}
	return self;
	}

	@end

	static void * INDBackgroundColorRangesKey = &INDBackgroundColorRangesKey;
	static void * INDHighlightedRangeKey = &INDHighlightedRangeKey;

	#define IND_DISABLED_SELECTED_TEXT_BG_COLOR [NSColor colorWithDeviceRed:0.83 green:0.83 blue:0.83 alpha:1.0]

	@interface NSTextView (INDSelectionHighlight)
	@property (nonatomic, strong) NSArray *ind_backgroundColorRanges;
	@property (nonatomic, assign) NSRange ind_highlightedRange;
	@end

	@implementation NSTextView (INDSelectionHighlight)

	- (void)ind_highlightSelectedTextInRange:(NSRange)range drawActive:(BOOL)active
	{
	if (self.ind_backgroundColorRanges == nil) {
	[self ind_backupBackgroundColorState];
	}
	self.ind_highlightedRange = range;

	NSColor *selectedColor = nil;
	if (active) {
	selectedColor = self.selectedTextAttributes[NSBackgroundColorAttributeName] ?: NSColor.selectedTextBackgroundColor;
	} else {
	selectedColor = IND_DISABLED_SELECTED_TEXT_BG_COLOR;
	}
	[self.textStorage beginEditing];
	[self.textStorage removeAttribute:NSBackgroundColorAttributeName range:NSMakeRange(0, self.textStorage.length)];
	[self.textStorage addAttribute:NSBackgroundColorAttributeName value:selectedColor range:range];
	[self.textStorage endEditing];
	[self setNeedsDisplay:YES];
	}

	- (void)ind_backupBackgroundColorState
	{
	NSMutableArray *ranges = [NSMutableArray array];
	NSString *attribute = NSBackgroundColorAttributeName;
	[self.textStorage enumerateAttribute:attribute inRange:NSMakeRange(0, self.textStorage.length) options:0 usingBlock:^(id value, NSRange range, BOOL *stop) {
	if (value == nil) return;
	INDAttributeRange *attrRange = [[INDAttributeRange alloc] initWithAttribute:attribute value:value range:range];
	[ranges addObject:attrRange];
	}];
	self.ind_backgroundColorRanges = ranges;
	}

	- (void)ind_deselectHighlightedText
	{
	[self.textStorage beginEditing];
	[self.textStorage removeAttribute:NSBackgroundColorAttributeName range:NSMakeRange(0, self.string.length)];
	NSArray *ranges = self.ind_backgroundColorRanges;
	for (INDAttributeRange *range in ranges) {
	[self.textStorage addAttribute:range.attribute value:range.value range:range.range];
	}
	[self.textStorage endEditing];
	[self setNeedsDisplay:YES];

	self.ind_backgroundColorRanges = nil;
	self.ind_highlightedRange = NSMakeRange(0, 0);
	}

	- (void)setInd_backgroundColorRanges:(NSArray *)ind_backgroundColorRanges
	{
	objc_setAssociatedObject(self, INDBackgroundColorRangesKey, ind_backgroundColorRanges, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
	}

	- (NSArray *)ind_backgroundColorRanges
	{
	return objc_getAssociatedObject(self, INDBackgroundColorRangesKey);
	}

	- (void)setInd_highlightedRange:(NSRange)ind_highlightedRange
	{
	objc_setAssociatedObject(self, INDHighlightedRangeKey, [NSValue valueWithRange:ind_highlightedRange], OBJC_ASSOCIATION_RETAIN_NONATOMIC);
	}

	- (NSRange)ind_highlightedRange
	{
	return [objc_getAssociatedObject(self, INDHighlightedRangeKey) rangeValue];
	}

	@end

	@interface INDTextViewSelectionRange : NSObject
	@property (nonatomic, copy, readonly) NSString *textViewIdentifier;
	@property (nonatomic, assign, readonly) NSRange range;
	@property (nonatomic, copy, readonly) NSAttributedString *attributedText;
	- (id)initWithTextView:(NSTextView *)textView selectedRange:(NSRange)range;
	@end

	@implementation INDTextViewSelectionRange

	- (id)initWithTextView:(NSTextView *)textView selectedRange:(NSRange)range
	{
	if ((self = [super init])) {
	_textViewIdentifier = [textView.ind_uniqueIdentifier copy];
	_range = range;
	_attributedText = [[textView.attributedString attributedSubstringFromRange:range] copy];
	}
	return self;
	}

	@end

	@interface INDTextViewSelectionSession : NSObject
	@property (nonatomic, copy, readonly) NSString *textViewIdentifier;
	@property (nonatomic, assign, readonly) NSUInteger characterIndex;
	@property (nonatomic, strong, readonly) NSDictionary *selectionRanges;
	@property (nonatomic, assign) NSPoint windowPoint;
	- (void)addSelectionRange:(INDTextViewSelectionRange *)range;
	- (void)removeSelectionRangeForTextView:(NSTextView *)textView;
	@end

	@implementation INDTextViewSelectionSession {
	NSMutableDictionary *_selectionRanges;
	}
	@synthesize selectionRanges = _selectionRanges;

	- (id)initWithTextView:(NSTextView )textView event:(NSEvent )event
	{
	if ((self = [super init])) {
	_textViewIdentifier = [textView.ind_uniqueIdentifier copy];
	_characterIndex = INDCharacterIndexForTextViewEvent(event, textView);
	_selectionRanges = [NSMutableDictionary dictionary];
	_windowPoint = event.locationInWindow;
	}
	return self;
	}

	- (void)addSelectionRange:(INDTextViewSelectionRange *)range
	{
	NSParameterAssert(range.textViewIdentifier);
	_selectionRanges[range.textViewIdentifier] = range;
	}

	- (void)removeSelectionRangeForTextView:(NSTextView *)textView
	{
	NSParameterAssert(textView.ind_uniqueIdentifier);
	[_selectionRanges removeObjectForKey:textView.ind_uniqueIdentifier];
	}

	@end

	@interface INDTextViewMetadata : NSObject
	@property (nonatomic, strong, readonly) NSTextView *textView;
	@property (nonatomic, copy, readonly) INDAttributedTextTransformationBlock transformationBlock;
	- (id)initWithTextView:(NSTextView *)textView transformationBlock:(INDAttributedTextTransformationBlock)transformationBlock;
	@end

	@implementation INDTextViewMetadata

	- (id)initWithTextView:(NSTextView *)textView transformationBlock:(INDAttributedTextTransformationBlock)transformationBlock
	{
	if ((self = [super init])) {
	_textView = textView;
	_transformationBlock = [transformationBlock copy];
	}
	return self;
	}

	@end

	@interface INDSequentialTextSelectionManager ()
	@property (nonatomic, strong, readonly) NSMutableDictionary *textViews;
	@property (nonatomic, strong, readonly) NSMutableOrderedSet *sortedTextViews;
	@property (nonatomic, strong) INDTextViewSelectionSession *currentSession;
	@property (nonatomic, strong) NSAttributedString *cachedAttributedText;
	@property (nonatomic, strong) id eventMonitor;
	@property (nonatomic, assign, getter = isFirstResponder) BOOL firstResponder;
	@end

	@implementation INDSequentialTextSelectionManager

	#pragma mark - Iniialization

	- (id)init
	{
	if ((self = [super init])) {
	_textViews = [NSMutableDictionary dictionary];
	_sortedTextViews = [NSMutableOrderedSet orderedSet];
	_eventMonitor = [self addLocalEventMonitor];
	}
	return self;
	}

	#pragma mark - Cleanup

	- (void)dealloc
	{
	[NSEvent removeMonitor:_eventMonitor];
	}

	#pragma mark - Events

	- (BOOL)handleLeftMouseDown:(NSEvent *)event
	{
	// Allow for correct handling of double clicks on text views.
	if (event.clickCount == 1) {
	[self endSession];

	NSTextView *textView = [self validTextViewForEvent:event];
	// Ignore if the text view is not "owned" by this manager, or if it is being
	// edited at the time of this event.
	if (textView && textView.window.firstResponder != textView) {
	self.currentSession = [[INDTextViewSelectionSession alloc] initWithTextView:textView event:event];
	return YES;
	}
	}
	return NO;
	}

	- (BOOL)handleLeftMouseUp:(NSEvent *)event
	{
	if (self.currentSession == nil) return NO;

	[event.window makeFirstResponder:self];
	NSTextView *textView = [self validTextViewForEvent:event];
	if (textView != nil) {
	// Handle link clicks properly.
	NSUInteger index = INDCharacterIndexForTextViewEvent(event, textView);
	if (index < textView.string.length) {
	NSDictionary *attributes = [textView.attributedString attributesAtIndex:index effectiveRange:NULL];
	id link = attributes[NSLinkAttributeName];

	// From documentation, NSLinkAttributeName could be either an NSString * or NSURL *
	if (link != nil) {
	[textView clickedOnLink:link atIndex:index];
	}
	}
	}
	return YES;
	}

	- (BOOL)handleLeftMouseDragged:(NSEvent *)event
	{
	if (self.currentSession == nil) return NO;

	NSTextView *textView = [self validTextViewForEvent:event];
	if (textView != nil) {
	[textView.window makeFirstResponder:textView];
	NSSelectionAffinity affinity = (event.locationInWindow.y < self.currentSession.windowPoint.y) ? NSSelectionAffinityDownstream : NSSelectionAffinityUpstream;
	self.currentSession.windowPoint = event.locationInWindow;

	NSUInteger current;
	NSString *identifier = self.currentSession.textViewIdentifier;
	if ([textView.ind_uniqueIdentifier isEqualTo:identifier]) {
	current = self.currentSession.characterIndex;
	} else {
	INDTextViewMetadata *meta = self.textViews[identifier];
	NSUInteger start = [self.sortedTextViews indexOfObject:meta.textView];
	NSUInteger end = [self.sortedTextViews indexOfObject:textView];
	current = (end >= start) ? 0 : textView.string.length;
	}
	NSUInteger index = INDCharacterIndexForTextViewEvent(event, textView);
	NSRange range = INDForwardRangeForIndices(index, current);
	[self setSelectionRangeForTextView:textView withRange:range];
	[self processCompleteSelectionsForTargetTextView:textView affinity:affinity];
	}
	return YES;
	}

	- (BOOL)handleRightMouseDown:(NSEvent *)event
	{
	if (self.currentSession == nil) return NO;

	[event.window makeFirstResponder:self];
	NSTextView *textView = [self validTextViewForEvent:event];
	if (textView != nil) {
	NSMenu *menu = [self menuForEvent:event];
	[NSMenu popUpContextMenu:menu withEvent:event forView:textView];
	}
	return YES;
	}

	- (id)addLocalEventMonitor
	{
	return [NSEvent addLocalMonitorForEventsMatchingMask:NSLeftMouseDownMask \| NSLeftMouseDraggedMask \| NSLeftMouseUpMask \| NSRightMouseDownMask handler:^NSEvent (NSEvent event) {
	switch (event.type) {
	case NSLeftMouseDown:
	return [self handleLeftMouseDown:event] ? nil : event;
	case NSLeftMouseDragged:
	return [self handleLeftMouseDragged:event] ? nil : event;
	case NSLeftMouseUp:
	return [self handleLeftMouseUp:event] ? nil : event;
	case NSRightMouseDown:
	return [self handleRightMouseDown:event] ? nil : event;
	default:
	return event;
	}
	}];
	}

	- (NSTextView )validTextViewForEvent:(NSEvent )event
	{
	NSView *contentView = event.window.contentView;
	NSPoint point = [contentView convertPoint:event.locationInWindow fromView:nil];
	NSView *view = [contentView hitTest:point];
	if ([view isKindOfClass:NSTextView.class]) {
	NSTextView textView = (NSTextView )view;
	NSString *identifier = textView.ind_uniqueIdentifier;
	return (textView.isSelectable && identifier && self.textViews[identifier]) ? textView : nil;
	}
	return nil;
	}

	#pragma mark - NSResponder

	- (NSAttributedString *)cachedAttributedText
	{
	if (_cachedAttributedText == nil) {
	_cachedAttributedText = [self buildAttributedStringForCurrentSession];
	}
	return _cachedAttributedText;
	}

	- (void)copy:(id)sender
	{
	NSPasteboard *pboard = NSPasteboard.generalPasteboard;
	[pboard clearContents];
	[pboard writeObjects:@[self.cachedAttributedText]];
	}

	- (NSMenu *)buildSharingMenu
	{
	NSMenu *shareMenu = [[NSMenu alloc] initWithTitle:NSLocalizedString(@"Share", nil)];
	NSArray *services = [NSSharingService sharingServicesForItems:@[self.cachedAttributedText]];
	for (NSSharingService *service in services) {
	NSMenuItem *item = [shareMenu addItemWithTitle:service.title action:@selector(share:) keyEquivalent:@""];
	item.target = self;
	item.image = service.image;
	item.representedObject = service;
	}
	return shareMenu;
	}

	- (NSMenu )menuForEvent:(NSEvent )theEvent
	{
	NSMenu *menu = [[NSMenu alloc] initWithTitle:NSLocalizedString(@"Text Actions", nil)];
	NSMenuItem *copy = [menu addItemWithTitle:NSLocalizedString(@"Copy", nil) action:@selector(copy:) keyEquivalent:@""];
	copy.target = self;
	[menu addItem:NSMenuItem.separatorItem];

	NSMenuItem *share = [menu addItemWithTitle:NSLocalizedString(@"Share", nil) action:nil keyEquivalent:@""];
	share.submenu = [self buildSharingMenu];

	return menu;
	}

	- (void)share:(NSMenuItem *)item
	{
	NSSharingService *service = item.representedObject;
	[service performWithItems:@[self.cachedAttributedText]];
	}

	- (void)rehighlightSelectedRangesAsActive:(BOOL)active
	{
	NSArray *ranges = self.currentSession.selectionRanges.allValues;
	for (INDTextViewSelectionRange *range in ranges) {
	INDTextViewMetadata *meta = self.textViews[range.textViewIdentifier];
	[meta.textView ind_highlightSelectedTextInRange:range.range drawActive:active];
	}
	}

	- (BOOL)resignFirstResponder
	{
	[self rehighlightSelectedRangesAsActive:NO];
	self.firstResponder = NO;
	return YES;
	}

	- (BOOL)becomeFirstResponder
	{
	[self rehighlightSelectedRangesAsActive:YES];
	self.firstResponder = YES;
	return YES;
	}

	#pragma mark - Selection

	- (void)setSelectionRangeForTextView:(NSTextView *)textView withRange:(NSRange)range
	{
	if (range.location == NSNotFound \|\| NSMaxRange(range) == 0) {
	[textView ind_deselectHighlightedText];
	[self.currentSession removeSelectionRangeForTextView:textView];
	} else {
	INDTextViewSelectionRange *selRange = [[INDTextViewSelectionRange alloc] initWithTextView:textView selectedRange:range];
	[self.currentSession addSelectionRange:selRange];
	[textView ind_highlightSelectedTextInRange:range drawActive:YES];
	}
	}

	- (void)processCompleteSelectionsForTargetTextView:(NSTextView *)textView affinity:(NSSelectionAffinity)affinity
	{
	if (self.currentSession == nil) return;

	INDTextViewMetadata *meta = self.textViews[self.currentSession.textViewIdentifier];
	NSUInteger start = [self.sortedTextViews indexOfObject:meta.textView];
	NSUInteger end = [self.sortedTextViews indexOfObject:textView];
	if (start == NSNotFound \|\| end == NSNotFound) return;

	NSRange subrange = NSMakeRange(NSNotFound, 0);
	BOOL select = NO;
	NSUInteger count = self.sortedTextViews.count;
	if (end > start) {
	if (affinity == NSSelectionAffinityDownstream) {
	subrange = NSMakeRange(start, end - start);
	select = YES;
	} else if (count > end + 1) {
	subrange = NSMakeRange(end + 1, count - end - 1);
	}
	} else if (end < start) {
	if (affinity == NSSelectionAffinityUpstream) {
	subrange = NSMakeRange(end + 1, start - end);
	select = YES;
	} else {
	subrange = NSMakeRange(0, end);
	}
	}
	NSArray *subarray = nil;
	if (subrange.location == NSNotFound) {
	NSMutableOrderedSet *views = [self.sortedTextViews mutableCopy];
	[views removeObject:textView];
	subarray = views.array;
	} else {
	subarray = [self.sortedTextViews.array subarrayWithRange:subrange];
	}
	for (NSTextView *tv in subarray) {
	NSRange range;
	if (select) {
	NSRange currentRange = tv.ind_highlightedRange;
	if (affinity == NSSelectionAffinityDownstream) {
	range = NSMakeRange(currentRange.location, tv.string.length - currentRange.location);
	} else {
	range = NSMakeRange(0, NSMaxRange(currentRange) ?: tv.string.length);
	}
	} else {
	range = NSMakeRange(0, 0);
	}
	[self setSelectionRangeForTextView:tv withRange:range];
	}
	}

	- (void)endSession
	{
	for (INDTextViewMetadata *meta in self.textViews.allValues) {
	[meta.textView ind_deselectHighlightedText];
	}
	self.currentSession = nil;
	self.cachedAttributedText = nil;
	}

	#pragma mark - Text

	- (NSAttributedString *)buildAttributedStringForCurrentSession
	{
	if (self.currentSession == nil) return nil;

	NSDictionary *ranges = self.currentSession.selectionRanges;
	NSMutableArray *keys = [ranges.allKeys mutableCopy];
	NSComparator textViewComparator = self.textViewComparator;
	[keys sortUsingComparator:^NSComparisonResult(NSString obj1, NSString obj2) {
	INDTextViewMetadata *meta1 = self.textViews[obj1];
	INDTextViewMetadata *meta2 = self.textViews[obj2];
	return textViewComparator(meta1.textView, meta2.textView);
	}];
	NSMutableAttributedString *string = [[NSMutableAttributedString alloc] init];
	[string beginEditing];
	[keys enumerateObjectsUsingBlock:^(NSString key, NSUInteger idx, BOOL stop) {
	INDTextViewSelectionRange *range = ranges[key];
	INDTextViewMetadata *meta = self.textViews[range.textViewIdentifier];
	NSAttributedString *fragment = range.attributedText;
	if (meta.transformationBlock != nil) {
	fragment = meta.transformationBlock(fragment);
	}
	[string appendAttributedString:fragment];
	if (string.length && idx != keys.count - 1) {
	NSDictionary *attributes = [string attributesAtIndex:string.length - 1 effectiveRange:NULL];
	NSAttributedString *newline = [[NSAttributedString alloc] initWithString:@"\n" attributes:attributes];
	[string appendAttributedString:newline];
	}
	}];
	[string endEditing];
	return string;
	}

	#pragma mark - Registration

	- (void)registerTextView:(NSTextView )textView withUniqueIdentifier:(NSString )identifier
	{
	[self registerTextView:textView withUniqueIdentifier:identifier transformationBlock:nil];
	}

	- (void)registerTextView:(NSTextView )textView withUniqueIdentifier:(NSString )identifier transformationBlock:(INDAttributedTextTransformationBlock)block
	{
	NSParameterAssert(identifier);
	NSParameterAssert(textView);

	[self unregisterTextView:textView];
	textView.ind_uniqueIdentifier = identifier;
	if (self.currentSession) {
	INDTextViewSelectionRange *range = self.currentSession.selectionRanges[identifier];
	if (range) {
	[textView ind_highlightSelectedTextInRange:range.range drawActive:self.firstResponder];
	}
	}
	self.textViews[identifier] = [[INDTextViewMetadata alloc] initWithTextView:textView transformationBlock:block];

	[self.sortedTextViews addObject:textView];
	[self sortTextViews];
	}

	- (NSComparator)textViewComparator
	{
	return ^NSComparisonResult(NSTextView obj1, NSTextView obj2) {
	// Convert to window coordinates to normalize coordinate flipped-ness
	NSRect frame1 = [obj1 convertRect:obj1.bounds toView:nil];
	NSRect frame2 = [obj2 convertRect:obj2.bounds toView:nil];

	CGFloat y1 = NSMinY(frame1);
	CGFloat y2 = NSMinY(frame2);

	if (y1 > y2) {
	return NSOrderedAscending;
	} else if (y1 < y2) {
	return NSOrderedDescending;
	} else {
	return NSOrderedSame;
	}
	};
	}

	- (void)sortTextViews
	{
	[self.sortedTextViews sortUsingComparator:self.textViewComparator];
	}

	- (void)unregisterTextView:(NSTextView *)textView
	{
	if (textView.ind_uniqueIdentifier == nil) return;
	[self.textViews removeObjectForKey:textView.ind_uniqueIdentifier];
	[self.sortedTextViews removeObject:textView];
	[self sortTextViews];

	textView.ind_uniqueIdentifier = nil;
	}

	- (void)unregisterAllTextViews
	{
	[self.textViews removeAllObjects];
	[self.sortedTextViews removeAllObjects];
	}

	@end