AGApplicationMoved.m

@implementation AppDelegate
{
	AGApplicationMoved * _moved;
}


- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
	_moved = [[AGApplicationMoved watchForApplicationMoving:^{
		[NSApp terminate:nil];
	}] retain];
	
	_moved.allowRelaunch = NO;
	_moved.allowContinue = YES;
}

@end




//
//  AGApplicationMoved.h
//  MovingApplication
//
//  Created by Seth Willits on 8/13/13.
//  Copyright (c) 2013 Seth Willits. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface AGApplicationMoved : NSObject
{
	NSURL * _mainBundleFileReferenceURL;
	void (^_terminationHandler)(void);
	FSEventStreamRef _stream;
	
	BOOL _allowRelaunch;
	BOOL _allowContinue;
	NSString * _localizedMessageText;
	NSString * _localizedInformativeText;
}


+ (AGApplicationMoved *)watchForApplicationMoving:(void (^)(void))terminationHandler;

@property (nonatomic, readwrite) BOOL allowRelaunch;
@property (nonatomic, readwrite) BOOL allowContinue;

@property (nonatomic, readwrite, copy) NSString * localizedMessageText;
@property (nonatomic, readwrite, copy) NSString * localizedInformativeText;

@end







//
//  AGApplicationMoved.m
//  MovingApplication
//
//  Created by Seth Willits on 8/13/13.
//  Copyright (c) 2013 Seth Willits. All rights reserved.
//

#import "AGApplicationMoved.h"

@interface AGApplicationMoved ()
- (void)checkForApplicationBeingMoved;
- (void)relaunchAfterTermination;
@end


@implementation AGApplicationMoved

+ (AGApplicationMoved *)watchForApplicationMoving:(void (^)(void))terminationHandler;
{
	return [[[AGApplicationMoved alloc] initWithTerminationHandler:terminationHandler] autorelease];
}



- (id)initWithTerminationHandler:(void (^)(void))terminationHandler;
{
	if (!(self = [super init])) {
		return nil;
	}
	
	_mainBundleFileReferenceURL = [[[[NSBundle mainBundle] bundleURL] fileReferenceURL] retain];
	_terminationHandler = [terminationHandler copy];
	
	
	FSEventStreamContext context;
	context.copyDescription = NULL;
	context.retain = NULL;
	context.release = NULL;
	context.info = self;
	context.version = 0;
	
	
	_stream = FSEventStreamCreate(NULL, MyFSEventStreamCallback, &context, (CFArrayRef)@[_mainBundleFileReferenceURL.relativePath], kFSEventStreamEventIdSinceNow, 0.0, kFSEventStreamCreateFlagUseCFTypes | kFSEventStreamCreateFlagWatchRoot);
	if (_stream) {
		FSEventStreamScheduleWithRunLoop(_stream, CFRunLoopGetMain(), kCFRunLoopDefaultMode);
		FSEventStreamStart(_stream);
	} else {
		[self release];
		return nil;
	}
	
	_allowRelaunch = NO;
	_allowContinue = YES;
	
	return self;
}



- (void)dealloc;
{
	if (_stream) {
		FSEventStreamStop(_stream);
		FSEventStreamInvalidate(_stream);
		FSEventStreamRelease(_stream);
	}
	
	[_terminationHandler release];
	[_mainBundleFileReferenceURL release];
	[_localizedMessageText release];
	[_localizedInformativeText release];
	[super dealloc];
}



@synthesize allowRelaunch = _allowRelaunch;
@synthesize allowContinue = _allowContinue;
@synthesize localizedMessageText = _localizedMessageText;
@synthesize localizedInformativeText = _localizedInformativeText;

- (NSString *)localizedMessageText;
{
	if (_localizedMessageText) {
		return _localizedMessageText;
	}
	
	NSString * appName = NSRunningApplication.currentApplication.localizedName;
	return [NSString stringWithFormat:@"%@ was moved or renamed while running which can cause problems.", appName];
}



- (NSString *)localizedInformativeText;
{
	if (_localizedInformativeText) {
		return _localizedInformativeText;
	}
	
	NSString * appName = NSRunningApplication.currentApplication.localizedName;
	NSString * inform = nil;
	
	if (self.allowContinue) {
		inform = [NSString stringWithFormat:@"Please quit and relaunch %@, or move the application back to its original location before continuing.", appName];
	} else {
		inform = [NSString stringWithFormat:@"Please quit and relaunch %@.", appName];
	}
	
	return inform;
}



- (void)checkForApplicationBeingMoved;
{
	if (![_mainBundleFileReferenceURL.relativePath isEqual:NSBundle.mainBundle.bundlePath]) {
		NSString * defaultBtn = (self.allowRelaunch ? NSLocalizedString(@"Relaunch", nil) : NSLocalizedString(@"Quit", nil));
		NSString * continueBtn = (self.allowContinue ? NSLocalizedString(@"Continue", nil) : nil);
		
		NSAlert * alert = [NSAlert alertWithMessageText:self.localizedMessageText defaultButton:defaultBtn alternateButton:continueBtn otherButton:nil informativeTextWithFormat:@"%@", self.localizedInformativeText];
		
		NSUInteger response = [alert runModal];
		if (response == NSAlertDefaultReturn) {
			if (self.allowRelaunch) {
				[self relaunchAfterTermination];
			}
			
			if (_terminationHandler) {
				_terminationHandler();
			} else {
				[NSApp terminate:nil];
			}
		}
	}
}



static void MyFSEventStreamCallback(ConstFSEventStreamRef streamRef, void *clientCallBackInfo, size_t numEvents, void *eventPaths, const FSEventStreamEventFlags eventFlags[], const FSEventStreamEventId eventIds[])
{
	for (size_t i = 0; i < numEvents; i++) {
		BOOL rootChanged = ((eventFlags[i] & kFSEventStreamEventFlagRootChanged) > 0);
		if (rootChanged) {
			[(AGApplicationMoved *)clientCallBackInfo checkForApplicationBeingMoved];
		}
	}
}



- (void)relaunchAfterTermination;
{
	// The shell script waits until the original app process terminates.
	// This is done so that the relaunched app opens as the front-most app.
	NSString * script = [NSString stringWithFormat:@"(while [ `ps -p %d | wc -l` -gt 1 ]; do sleep 0.1; done; open '%@') &",
						 NSProcessInfo.processInfo.processIdentifier,
						 _mainBundleFileReferenceURL.relativePath];
	
	@try {
		[NSTask launchedTaskWithLaunchPath:@"/bin/sh" arguments:@[@"-c", script]];
	}
	@catch (id e) {}
}


@end