/*
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File: DirectoryWatcher.m
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Abstract:
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Object used to monitor the contents of a given directory by using
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"kqueue": a kernel event notification mechanism.
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Version: 1.4
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Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
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Inc. ("Apple") in consideration of your agreement to the following
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terms, and your use, installation, modification or redistribution of
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this Apple software constitutes acceptance of these terms. If you do
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not agree with these terms, please do not use, install, modify or
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redistribute this Apple software.
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In consideration of your agreement to abide by the following terms, and
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subject to these terms, Apple grants you a personal, non-exclusive
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license, under Apple's copyrights in this original Apple software (the
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"Apple Software"), to use, reproduce, modify and redistribute the Apple
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Software, with or without modifications, in source and/or binary forms;
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provided that if you redistribute the Apple Software in its entirety and
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without modifications, you must retain this notice and the following
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text and disclaimers in all such redistributions of the Apple Software.
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Neither the name, trademarks, service marks or logos of Apple Inc. may
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be used to endorse or promote products derived from the Apple Software
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without specific prior written permission from Apple. Except as
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expressly stated in this notice, no other rights or licenses, express or
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implied, are granted by Apple herein, including but not limited to any
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patent rights that may be infringed by your derivative works or by other
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works in which the Apple Software may be incorporated.
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The Apple Software is provided by Apple on an "AS IS" basis. APPLE
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MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
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THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
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FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
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OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
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IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
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MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
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AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
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STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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Copyright (C) 2012 Apple Inc. All Rights Reserved.
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*/
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#import "DirectoryWatcher.h"
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#include <sys/types.h>
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#include <sys/event.h>
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#include <sys/time.h>
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#include <fcntl.h>
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#include <unistd.h>
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#import <CoreFoundation/CoreFoundation.h>
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@interface DirectoryWatcher (DirectoryWatcherPrivate)
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- (BOOL)startMonitoringDirectory:(NSString *)dirPath;
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- (void)kqueueFired;
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@end
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#pragma mark -
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@implementation DirectoryWatcher
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@synthesize delegate;
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- (id)init
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{
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self= [super init];
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delegate = NULL;
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dirFD = -1;
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kq = -1;
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dirKQRef = NULL;
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return self;
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}
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- (void)dealloc
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{
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[self invalidate];
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}
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+ (DirectoryWatcher *)watchFolderWithPath:(NSString *)watchPath delegate:(id)watchDelegate
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{
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DirectoryWatcher *retVal = NULL;
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if ((watchDelegate != NULL) && (watchPath != NULL))
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{
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DirectoryWatcher *tempManager = [[DirectoryWatcher alloc] init];
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tempManager.delegate = watchDelegate;
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if ([tempManager startMonitoringDirectory: watchPath])
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{
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// Everything appears to be in order, so return the DirectoryWatcher.
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// Otherwise we'll fall through and return NULL.
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retVal = tempManager;
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}
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}
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return retVal;
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}
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- (void)invalidate
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{
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if (dirKQRef != NULL)
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{
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CFFileDescriptorInvalidate(dirKQRef);
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CFRelease(dirKQRef);
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dirKQRef = NULL;
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// We don't need to close the kq, CFFileDescriptorInvalidate closed it instead.
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// Change the value so no one thinks it's still live.
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kq = -1;
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}
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if(dirFD != -1)
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{
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close(dirFD);
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dirFD = -1;
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}
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}
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@end
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#pragma mark -
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@implementation DirectoryWatcher (DirectoryWatcherPrivate)
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- (void)kqueueFired
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{
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assert(kq >= 0);
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struct kevent event;
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struct timespec timeout = {0, 0};
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int eventCount;
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eventCount = kevent(kq, NULL, 0, &event, 1, &timeout);
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assert((eventCount >= 0) && (eventCount < 2));
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// call our delegate of the directory change
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[delegate directoryDidChange:self];
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CFFileDescriptorEnableCallBacks(dirKQRef, kCFFileDescriptorReadCallBack);
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}
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static void KQCallback(CFFileDescriptorRef kqRef, CFOptionFlags callBackTypes, void *info)
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{
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DirectoryWatcher *obj;
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obj = (__bridge DirectoryWatcher *)info;
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assert([obj isKindOfClass:[DirectoryWatcher class]]);
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assert(kqRef == obj->dirKQRef);
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assert(callBackTypes == kCFFileDescriptorReadCallBack);
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[obj kqueueFired];
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}
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- (BOOL)startMonitoringDirectory:(NSString *)dirPath
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{
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// Double initializing is not going to work...
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if ((dirKQRef == NULL) && (dirFD == -1) && (kq == -1))
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{
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// Open the directory we're going to watch
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dirFD = open([dirPath fileSystemRepresentation], O_EVTONLY);
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if (dirFD >= 0)
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{
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// Create a kqueue for our event messages...
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kq = kqueue();
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if (kq >= 0)
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{
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struct kevent eventToAdd;
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eventToAdd.ident = dirFD;
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eventToAdd.filter = EVFILT_VNODE;
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eventToAdd.flags = EV_ADD | EV_CLEAR;
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eventToAdd.fflags = NOTE_WRITE;
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eventToAdd.data = 0;
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eventToAdd.udata = NULL;
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int errNum = kevent(kq, &eventToAdd, 1, NULL, 0, NULL);
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if (errNum == 0)
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{
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CFFileDescriptorContext context = { 0, (__bridge void *)(self), NULL, NULL, NULL };
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CFRunLoopSourceRef rls;
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// Passing true in the third argument so CFFileDescriptorInvalidate will close kq.
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dirKQRef = CFFileDescriptorCreate(NULL, kq, true, KQCallback, &context);
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if (dirKQRef != NULL)
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{
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rls = CFFileDescriptorCreateRunLoopSource(NULL, dirKQRef, 0);
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if (rls != NULL)
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{
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CFRunLoopAddSource(CFRunLoopGetCurrent(), rls, kCFRunLoopDefaultMode);
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CFRelease(rls);
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CFFileDescriptorEnableCallBacks(dirKQRef, kCFFileDescriptorReadCallBack);
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// If everything worked, return early and bypass shutting things down
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return YES;
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}
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// Couldn't create a runloop source, invalidate and release the CFFileDescriptorRef
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CFFileDescriptorInvalidate(dirKQRef);
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CFRelease(dirKQRef);
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dirKQRef = NULL;
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}
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}
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// kq is active, but something failed, close the handle...
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close(kq);
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kq = -1;
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}
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// file handle is open, but something failed, close the handle...
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close(dirFD);
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dirFD = -1;
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}
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}
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return NO;
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}
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@end
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