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QuickLookDownloader/MyDocument.m

/*

 Copyright (C) 2017 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 MyDocument manages a list of downloaded items.

*/

#import "MyDocument.h"

#import "DownloadItem.h"

#import "DownloadCell.h"

@import Quartz;   // Quartz framework provides the QLPreviewPanel public API

// DownloadItem will be used directlty as the items in preview panel

// The class just need to implement the QLPreviewItem protocol

//

@interface DownloadItem (QLPreviewItem) <QLPreviewItem>

@end

#pragma mark -

@implementation DownloadItem (QLPreviewItem)

- (NSURL *)previewItemURL

    return self.resolvedFileURL;

- (NSString *)previewItemTitle

    return [self.originalURL absoluteString];

@end

#pragma mark -

@interface MyDocument () <QLPreviewPanelDataSource, QLPreviewPanelDelegate, NSURLDownloadDelegate, NSTextFieldDelegate>

    BOOL downloading;

@property (strong) NSMutableArray *downloads;

@property (strong) NSURLDownload *download;

@property (assign) long long downloadedSoFar;

@property (assign) long long expectedContentLength;

@property (strong) NSURL *originalURL;

@property (strong) NSURL *targetFileURL;

@property (getter = isDownloading, setter = setDownloading:) BOOL downloading;

@property CGFloat downloadProgress;

@property BOOL downloadIsIndeterminate;

@property (nonatomic, copy) NSArray *selectedDownloads;

@property (nonatomic, copy) NSIndexSet *selectedIndexes;

@property IBOutlet NSTextField *downloadURLField;

@property IBOutlet NSView *downloadsView;

@property IBOutlet NSTableView *downloadsTableView;

@property IBOutlet NSButton *downloadButton;

@property IBOutlet NSView *downloadProgressView;

@property (strong) QLPreviewPanel *previewPanel;

@end

#pragma mark -

@implementation MyDocument

- (id)init

    self = [super init];

    if (self != nil)

        _downloads = [[NSMutableArray alloc] init];

        _selectedIndexes = [[NSIndexSet alloc] init];

    return self;

- (void)dealloc

    [self.download cancel];

- (NSString *)windowNibName

    return @"MyDocument";

// write method of NSDocument

//

- (NSData *)dataOfType:(NSString *)typeName error:(NSError **)outError

    NSMutableArray *propertyList = [[NSMutableArray alloc] initWithCapacity:self.downloads.count];

    for (DownloadItem *item in self.downloads)

        id plistForItem = [item propertyListForSaving];

        if (plistForItem)

            [propertyList addObject:plistForItem];

    NSData *result = [NSPropertyListSerialization dataWithPropertyList:propertyList

                                                                format:NSPropertyListBinaryFormat_v1_0

                                                               options:0

                                                                 error:NULL];

    assert(result);

    return result;

// read method of NSDocument

//

- (BOOL)readFromData:(NSData *)data ofType:(NSString *)typeName error:(NSError **)outError

    NSArray *propertyList = [NSPropertyListSerialization propertyListWithData:data

                                                                      options:NSPropertyListImmutable

                                                                       format:NULL

                                                                        error:outError];

    if (!propertyList)

        return NO;

    if (![propertyList isKindOfClass:[NSArray class]])

        if (outError != NULL)

            *outError = [NSError errorWithDomain:NSCocoaErrorDomain

                                            code:NSFileReadCorruptFileError

                                        userInfo:NULL];

        return NO;

    NSMutableArray *observableDownloads = [self mutableArrayValueForKey:@"downloads"];

    [observableDownloads removeAllObjects];

    for (id plistItem in propertyList)

        DownloadItem *item = [[DownloadItem alloc] initWithSavedPropertyList:plistItem];

        if (item)

            [observableDownloads addObject:item];

    return YES;

#pragma mark - Downloading

// the URL field text has changed, update the enable state of our Download button

- (void)controlTextDidChange:(NSNotification *)obj

    NSTextField *textField = [obj object];

    [self.downloadButton setEnabled:(textField.stringValue.length > 0)];

// called when the user clicks the Download button

- (IBAction)startDownload:(id)sender

    assert(!self.download);

    [self.downloadButton setEnabled:NO]; // don't allow download button to work while downloading

    NSString *urlString = [self.downloadURLField stringValue];

    assert(urlString);

    urlString = [urlString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

    NSURL *url = [NSURL URLWithString:urlString];

    _originalURL = [url copy];

    NSURLRequest *request = [NSURLRequest requestWithURL:url];

    self.downloadIsIndeterminate = YES;

    self.downloadProgress = 0.0f;

    self.downloading = YES;

    _download = [[NSURLDownload alloc] initWithRequest:request delegate:self];

    [[self.downloadsTableView window] makeFirstResponder:self.downloadsTableView];

- (void)setSelectedIndexes:(NSIndexSet *)indexSet

    if (indexSet != _selectedIndexes)

        indexSet = [indexSet copy];

        _selectedIndexes = indexSet;

        self.selectedDownloads = [self.downloads objectsAtIndexes:indexSet];

- (void)setSelectedDownloads:(NSArray *)array

    if (array != _selectedDownloads)

        array = [array copy];

        _selectedDownloads = array;

        [self.previewPanel reloadData];

#pragma mark - Download support

- (void)displayDownloadProgressView

    if (self.downloading && self.downloadProgressView.superview == nil)

        // position and size downloadsProgressFrame appropriately

        NSRect downloadProgressFrame = self.downloadProgressView.frame;

        NSRect downloadsFrame = self.downloadsView.frame;

        downloadProgressFrame.size.width = CGRectGetWidth(downloadsFrame);

        downloadProgressFrame.origin.y = NSMaxY(downloadsFrame);

        [self.downloadProgressView setFrame:downloadProgressFrame];

        [[[self.downloadsView superview] animator] addSubview:self.downloadProgressView

                                                   positioned:NSWindowBelow

                                                   relativeTo:self.downloadsView];

- (void)startDisplayingProgressView

    if (!self.downloading || [self.downloadProgressView superview])

        return;

    // we are starting a download, display the download progress view

    NSRect downloadProgressFrame = self.downloadProgressView.frame;

    NSRect downloadsFrame = self.downloadsView.frame;

    // reduce the size of the downloads view

    downloadsFrame.size.height -= CGRectGetHeight(downloadProgressFrame);

    [NSAnimationContext beginGrouping];

        [[NSAnimationContext currentContext] setDuration:0.2];

        [[self.downloadsView animator] setFrame:downloadsFrame];

    [NSAnimationContext endGrouping];

    [self performSelector:@selector(displayDownloadProgressView) withObject:nil afterDelay:0.2];

- (void)hideDownloadProgressView

    if (!self.downloading)

        [NSObject cancelPreviousPerformRequestsWithTarget:self

                                                 selector:@selector(displayDownloadProgressView)

                                                   object:nil];

        // we are ending a download, remove the download progress view

        [self.downloadProgressView removeFromSuperview];

        [NSAnimationContext beginGrouping];

            [[NSAnimationContext currentContext] setDuration:0.5];

            [[self.downloadsView animator] setFrame:[[self.downloadsView superview] bounds]];

        [NSAnimationContext endGrouping];

- (BOOL)isDownloading

    return downloading;

- (void)setDownloading:(BOOL)flag

    if (!flag != !downloading)

        downloading = flag;

        if (downloading)

            [self performSelector:@selector(startDisplayingProgressView) withObject:nil afterDelay:0.0];

        else

            [self performSelector:@selector(hideDownloadProgressView) withObject:nil afterDelay:0.1];

            _originalURL = nil;

            _targetFileURL = nil;

            _download = nil;

- (void)download:(NSURLDownload *)download didReceiveResponse:(NSURLResponse *)response

    _expectedContentLength = [response expectedContentLength];

    if (self.expectedContentLength > 0.0)

        self.downloadIsIndeterminate = NO;

        _downloadedSoFar = 0;

- (void)download:(NSURLDownload *)download didReceiveDataOfLength:(NSUInteger)length

    _downloadedSoFar += length;

    if (self.downloadedSoFar >= self.expectedContentLength)

        // the expected content length was wrong as we downloaded more than expected

        // make the progress indeterminate

//

        self.downloadIsIndeterminate = YES;

    else

        self.downloadProgress = (float)self.downloadedSoFar / (float)self.expectedContentLength;

- (void)download:(NSURLDownload *)aDownload decideDestinationWithSuggestedFilename:(NSString *)filename

    // find the user's Downloads folder

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDownloadsDirectory, NSUserDomainMask, YES);

    NSString *documentsDirectory = paths[0];

    NSString *downloadPath = [documentsDirectory stringByAppendingPathComponent:filename];

    [aDownload setDestination:downloadPath allowOverwrite:NO];

- (void)download:(NSURLDownload *)download didCreateDestination:(NSString *)path

    _targetFileURL = [[NSURL alloc] initFileURLWithPath:path];

- (void)downloadDidFinish:(NSURLDownload *)download

    if (self.originalURL && self.targetFileURL)

        DownloadItem *item = [[DownloadItem alloc] initWithOriginalURL:self.originalURL fileURL:self.targetFileURL];

        if (item != nil)

            [[self mutableArrayValueForKey:@"downloads"] addObject:item];

            [self updateChangeCount:NSChangeDone];

        else

            NSLog(@"Can't create download item at %@", self.targetFileURL);

    self.downloading = NO;

    [self.downloadButton setEnabled:YES];    // allow for downloads again

- (void)download:(NSURLDownload *)aDownload didFailWithError:(NSError *)error

    [self presentError:error modalForWindow:[self windowForSheet] delegate:nil didPresentSelector:NULL contextInfo:NULL];

    self.downloading = NO;

#pragma mark - NSTableViewDelegate

- (void)tableView:(NSTableView *)tableView willDisplayCell:(id)cell forTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row

    if ([[tableColumn identifier] isEqual:@"Filename"])

        ((DownloadCell *)cell).originalURL = ((DownloadItem *)self.downloads[row]).originalURL;

        [cell setFont:[NSFont systemFontOfSize:TEXT_SIZE]];

#pragma mark - Quick Look panel support

- (BOOL)acceptsPreviewPanelControl:(QLPreviewPanel *)panel

    return YES;

- (void)beginPreviewPanelControl:(QLPreviewPanel *)panel

    // This document is now responsible of the preview panel

    // It is allowed to set the delegate, data source and refresh panel.

//

    _previewPanel = panel;

    panel.delegate = self;

    panel.dataSource = self;

- (void)endPreviewPanelControl:(QLPreviewPanel *)panel

    // This document loses its responsisibility on the preview panel

    // Until the next call to -beginPreviewPanelControl: it must not

    // change the panel's delegate, data source or refresh it.

//

    _previewPanel = nil;

#pragma mark - QLPreviewPanelDataSource

- (NSInteger)numberOfPreviewItemsInPreviewPanel:(QLPreviewPanel *)panel

    return self.selectedDownloads.count;

- (id <QLPreviewItem>)previewPanel:(QLPreviewPanel *)panel previewItemAtIndex:(NSInteger)index

    return (self.selectedDownloads)[index];

#pragma mark - QLPreviewPanelDelegate

- (BOOL)previewPanel:(QLPreviewPanel *)panel handleEvent:(NSEvent *)event

    // redirect all key down events to the table view

    if ([event type] == NSKeyDown)

        [self.downloadsTableView keyDown:event];

        return YES;

    return NO;

// This delegate method provides the rect on screen from which the panel will zoom.

- (NSRect)previewPanel:(QLPreviewPanel *)panel sourceFrameOnScreenForPreviewItem:(id <QLPreviewItem>)item

    NSRect returnIconRect = NSZeroRect;

    NSInteger index = [self.downloads indexOfObject:item];

    if (index != NSNotFound)

        NSRect iconRect = [self.downloadsTableView frameOfCellAtColumn:0 row:index];

        // Check that the icon rect is visible on screen.

        NSRect visibleRect = [self.downloadsTableView visibleRect];

        if (NSIntersectsRect(visibleRect, iconRect))

            // Convert icon rect to screen coordinates.

            NSRect convertedRect = [self.downloadsTableView convertRect:iconRect toView:nil];

            convertedRect.origin = [self.downloadsTableView.window convertRectToScreen:convertedRect].origin;

            returnIconRect = convertedRect;

    return returnIconRect;

// this delegate method provides a transition image between the table view and the preview panel

//

- (id)previewPanel:(QLPreviewPanel *)panel transitionImageForPreviewItem:(id <QLPreviewItem>)item contentRect:(NSRect *)contentRect

    DownloadItem *downloadItem = (DownloadItem *)item;

    return downloadItem.iconImage;

@end

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