#import "ASTextKitContext.h"

#import "ASLayoutManager.h"

#import "ASThread.h"

#include <memory>

@implementation ASTextKitContext

{

// All TextKit operations (even non-mutative ones) must be executed serially.

std::shared_ptr<ASDN::Mutex> __instanceLock__;

NSLayoutManager *_layoutManager;

NSTextStorage *_textStorage;

NSTextContainer *_textContainer;

}

- (instancetype)initWithAttributedString:(NSAttributedString *)attributedString

lineBreakMode:(NSLineBreakMode)lineBreakMode

maximumNumberOfLines:(NSUInteger)maximumNumberOfLines

exclusionPaths:(NSArray *)exclusionPaths

constrainedSize:(CGSize)constrainedSize

{

if (self = [super init]) {

// Concurrently initialising TextKit components crashes (rdar://18448377) so we use a global lock.

static ASDN::Mutex __staticMutex;

ASDN::MutexLocker l(__staticMutex);

__instanceLock__ = std::make_shared<ASDN::Mutex>();

// Create the TextKit component stack with our default configuration.

_textStorage = (attributedString ? [[NSTextStorage alloc] initWithAttributedString:attributedString] : [[NSTextStorage alloc] init]);

_layoutManager = [[ASLayoutManager alloc] init];

_layoutManager.usesFontLeading = NO;

[_textStorage addLayoutManager:_layoutManager];

_textContainer = [[NSTextContainer alloc] initWithSize:constrainedSize];

// We want the text laid out up to the very edges of the container.

_textContainer.lineFragmentPadding = 0;

_textContainer.lineBreakMode = lineBreakMode;

_textContainer.maximumNumberOfLines = maximumNumberOfLines;

_textContainer.exclusionPaths = exclusionPaths;

[_layoutManager addTextContainer:_textContainer];

}

return self;

}

- (void)performBlockWithLockedTextKitComponents:(void (^)(NSLayoutManager *,

NSTextStorage *,

NSTextContainer *))block

{

ASDN::MutexSharedLocker l(__instanceLock__);

if (block) {

block(_layoutManager, _textStorage, _textContainer);

}

}