/*

    File:       DNSSDBrowser.m

    Contains:   Uses the low-level DNS-SD API to browse for Bonjour services.

    Written by: DTS

    Copyright:  Copyright (c) 2011 Apple Inc. All Rights Reserved.

    Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc.

                ("Apple") in consideration of your agreement to the following

                terms, and your use, installation, modification or

                redistribution of this Apple software constitutes acceptance of

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                not use, install, modify or redistribute this Apple software.

                In consideration of your agreement to abide by the following

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                non-exclusive license, under Apple's copyrights in this

                original Apple software (the "Apple Software"), to use,

                reproduce, modify and redistribute the Apple Software, with or

                without modifications, in source and/or binary forms; provided

                that if you redistribute the Apple Software in its entirety and

                without modifications, you must retain this notice and the

                following text and disclaimers in all such redistributions of

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                or logos of Apple Inc. may be used to endorse or promote

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                this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any

                patent rights that may be infringed by your derivative works or

                by other works in which the Apple Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis. 

                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING

                WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT,

                MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING

                THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

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*/

#import "DNSSDBrowser.h"

#include <dns_sd.h>

#pragma mark * DNSSDBrowser

@interface DNSSDBrowser ()

// private properties

@property (assign, readwrite) DNSServiceRef      sdRef;

// forward declarations

- (void)stopWithError:(NSError *)error notify:(BOOL)notify;

@end

@implementation DNSSDBrowser

@synthesize domain = domain_;

@synthesize type = type_;

@synthesize delegate = delegate_;

@synthesize sdRef = sdRef_;

- (id)initWithDomain:(NSString *)domain type:(NSString *)type

    // See comment in header.

{

    // domain may be nil or empty

    assert( ! [domain hasPrefix:@"."] );

    assert(type != nil);

    assert([type length] != 0);

    assert( ! [type hasPrefix:@"."] );

    self = [super init];

    if (self != nil) {

        if ( ([domain length] != 0) && ! [domain hasSuffix:@"."] ) {

            domain = [domain stringByAppendingString:@"."];

        }

        if ( ! [type hasSuffix:@"."] ) {

            type = [type stringByAppendingString:@"."];

        }

        self->domain_ = [domain copy];

        self->type_ = [type copy];

    }

    return self;

}

- (void)dealloc

{

    if (self->sdRef_ != NULL) {

        DNSServiceRefDeallocate(self->sdRef_);

    }

    [self->domain_ release];

    [self->type_ release];

    [super dealloc];

}

- (void)browseReplyWithFlags:(DNSServiceFlags)flags domain:(NSString *)domain type:(NSString *)type name:(NSString *)name

    // Called when DNS-SD tells us that a service has been discovered or lost.

{

    BOOL            moreComing;

    DNSSDService *   service;

    assert(domain != nil);

    assert(type   != nil);

    assert(name   != nil);

    moreComing = (flags & kDNSServiceFlagsMoreComing) != 0;

    service = [[[DNSSDService alloc] initWithDomain:domain type:type name:name] autorelease];

    assert(service != nil);

    if (flags & kDNSServiceFlagsAdd) {

        if ([self.delegate respondsToSelector:@selector(dnssdBrowser:didAddService:moreComing:)]) {

            [self.delegate dnssdBrowser:self didAddService:service moreComing:moreComing];

        }

    } else {

        if ([self.delegate respondsToSelector:@selector(dnssdBrowser:didRemoveService:moreComing:)]) {

            [self.delegate dnssdBrowser:self didRemoveService:service moreComing:moreComing];

        }

    }

}

static void BrowseReplyCallback(

    DNSServiceRef                       sdRef,

    DNSServiceFlags                     flags,

    uint32_t                            interfaceIndex,

    DNSServiceErrorType                 errorCode,

    const char                          *serviceName,

    const char                          *regtype,

    const char                          *replyDomain,

    void                                *context

)

    // Called by DNS-SD when something happens with the browse operation.

{

    DNSSDBrowser *    obj;

    #pragma unused(interfaceIndex)

    assert([NSThread isMainThread]);        // because sdRef dispatches to the main queue

    obj = (DNSSDBrowser *) context;

    assert([obj isKindOfClass:[DNSSDBrowser class]]);

    assert(sdRef == obj->sdRef_);

    #pragma unused(sdRef)

    if (errorCode == kDNSServiceErr_NoError) {

        [obj browseReplyWithFlags:flags domain:[NSString stringWithUTF8String:replyDomain] type:[NSString stringWithUTF8String:regtype] name:[NSString stringWithUTF8String:serviceName]];

    } else {

        [obj stopWithError:[NSError errorWithDomain:NSNetServicesErrorDomain code:errorCode userInfo:nil] notify:YES];

    }

}

- (void)startBrowse

    // See comment in header.

{

    NSString *              domain;

    DNSServiceErrorType     errorCode;

    if (self.sdRef == NULL) {

        domain = self.domain;

        if (domain == nil) {

            domain = @"";

        }

        errorCode = DNSServiceBrowse(&self->sdRef_, 0, kDNSServiceInterfaceIndexAny, [self.type UTF8String], [domain UTF8String], BrowseReplyCallback, self);

        if (errorCode == kDNSServiceErr_NoError) {

            errorCode = DNSServiceSetDispatchQueue(self.sdRef, dispatch_get_main_queue());

        }

        if (errorCode == kDNSServiceErr_NoError) {

            if ([self.delegate respondsToSelector:@selector(dnssdBrowserWillBrowse:)]) {

                [self.delegate dnssdBrowserWillBrowse:self];

            }

        } else {

            [self stopWithError:[NSError errorWithDomain:NSNetServicesErrorDomain code:errorCode userInfo:nil] notify:YES];

        }

    }

}

- (void)stopWithError:(NSError *)error notify:(BOOL)notify

    // An internal bottleneck for shutting down the object.

{

    if (notify) {

        if (error != nil) {

            if ([self.delegate respondsToSelector:@selector(dnssdBrowser:didNotBrowse:)]) {

                [self.delegate dnssdBrowser:self didNotBrowse:error];

            }

        }

    }

    if (self.sdRef != NULL) {

        DNSServiceRefDeallocate(self.sdRef);

        self.sdRef = NULL;

    }

    if (notify) {

        if ([self.delegate respondsToSelector:@selector(dnssdBrowserDidStopBrowse:)]) {

            [self.delegate dnssdBrowserDidStopBrowse:self];

        }

    }

}

- (void)stop

    // See comment in header.

{

    [self stopWithError:nil notify:NO];

}

@end