arq_restore/http/StreamPairFactory.m

/*
 Copyright (c) 2009-2010, Stefan Reitshamer http://www.haystacksoftware.com
 
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
 
 * Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.
 
 * Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
 
 * Neither the names of PhotoMinds LLC or Haystack Software, nor the names of 
 their contributors may be used to endorse or promote products derived from
 this software without specific prior written permission.
 
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

#import "StreamPairFactory.h"
#import "CFStreamPair.h"

static StreamPairFactory *theFactory = nil;

#define DEFAULT_MAX_STREAM_PAIR_LIFETIME_SECONDS (60)
#define CLEANUP_THREAD_SLEEP_SECONDS (5)

@interface StreamPairMap : NSObject {
    NSMutableDictionary *streamPairs;
}
- (id <StreamPair>)newStreamPairToHost:(NSString *)host port:(int)thePort useSSL:(BOOL)useSSL maxLifeTimeSeconds:(NSTimeInterval)theMaxLifetime error:(NSError **)error;
- (void)dropUnusableStreamPairs;
@end

@implementation StreamPairMap
- (id)init {
    if (self = [super init]) {
        streamPairs = [[NSMutableDictionary alloc] init];
    }
    return self;
}
- (void)dealloc {
    [streamPairs release];
    [super dealloc];
}
- (id <StreamPair>)newStreamPairToHost:(NSString *)host port:(int)thePort useSSL:(BOOL)useSSL maxLifeTimeSeconds:(NSTimeInterval)theMaxLifetime error:(NSError **)error {
    NSString *key = [NSString stringWithFormat:@"%@:%d:%@", [host lowercaseString], thePort, (useSSL ? @"SSL" : @"noSSL")];
    id <StreamPair> streamPair = [streamPairs objectForKey:key];
    if (streamPair != nil) {
        if (![streamPair isUsable]) {
            [streamPairs removeObjectForKey:key];
            streamPair = nil;
        } else {
            [streamPair retain];
        }
    }
    if (streamPair == nil) {
        streamPair = [[CFStreamPair alloc] initWithHost:host port:thePort useSSL:useSSL maxLifetime:theMaxLifetime];
        [streamPairs setObject:streamPair forKey:key];
    }
    return streamPair;
}
- (void)dropUnusableStreamPairs {
    NSMutableArray *keysToDrop = [NSMutableArray array];
    for (NSString *key in streamPairs) {
        id <StreamPair> streamPair = [streamPairs objectForKey:key];
        if (![streamPair isUsable]) {
            [keysToDrop addObject:key];
        }
    }
    [streamPairs removeObjectsForKeys:keysToDrop];
}
@end



@implementation StreamPairFactory
+ (StreamPairFactory *)theFactory {
    if (theFactory == nil) {
        theFactory = [[super allocWithZone:NULL] init];
    }
    return theFactory;
}

/* Singleton recipe: */
+ (id)allocWithZone:(NSZone *)zone {
    return [[StreamPairFactory theFactory] retain];
}
- (id)copyWithZone:(NSZone *)zone {
    return self;
}
- (id)retain {
    return self;
}
- (NSUInteger)retainCount {
    return NSUIntegerMax;  //denotes an object that cannot be released
}
- (void)release {
    //do nothing
}
- (id)autorelease {
    return self;
}

- (id)init {
    if (self = [super init]) {
        lock = [[NSLock alloc] init];
        [lock setName:@"SocketFactory lock"];
        threadMap = [[NSMutableDictionary alloc] init];
        maxStreamPairLifetime = DEFAULT_MAX_STREAM_PAIR_LIFETIME_SECONDS;
        [NSThread detachNewThreadSelector:@selector(dropUnusableSockets) toTarget:self withObject:nil];
    }
    return self;
}
- (void)dealloc {
    [lock release];
    [threadMap release];
    [super dealloc];
}
- (void)setMaxStreamPairLifetime:(NSTimeInterval)theMaxLifetime {
    maxStreamPairLifetime = theMaxLifetime;
}
- (id <StreamPair>)newStreamPairToHost:(NSString *)theHost port:(int)thePort useSSL:(BOOL)isUseSSL error:(NSError **)error {
    void *pthreadPtr = pthread_self();
#ifdef __LP64__
    NSNumber *threadID = [NSNumber numberWithUnsignedLongLong:(uint64_t)pthreadPtr];
#else
    NSNumber *threadID = [NSNumber numberWithUnsignedLong:(uint32_t)pthreadPtr];
#endif
    [lock lock];
    StreamPairMap *map = [threadMap objectForKey:threadID];
    if (map == nil) {
        map = [[StreamPairMap alloc] init];
        [threadMap setObject:map forKey:threadID];
        [map release];
    }
    id <StreamPair> streamPair = [map newStreamPairToHost:theHost port:thePort useSSL:isUseSSL maxLifeTimeSeconds:maxStreamPairLifetime error:error];
    [lock unlock];
    return streamPair;
}
- (void)clear {
    [lock lock];
    [threadMap removeAllObjects];
    [lock unlock];
}

#pragma mark cleanup thread
- (void)dropUnusableSockets {
    for (;;) {
        NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
        @try {
            [NSThread sleepForTimeInterval:CLEANUP_THREAD_SLEEP_SECONDS];
            [lock lock];
            for (StreamPairMap *map in [threadMap allValues]) {
                [map dropUnusableStreamPairs];
            }
            [lock unlock];
        } @catch(NSException *e) {
            HSLogError(@"unexpected exception in StreamPairFactory cleanup thread: %@", [e description]);
        }
        [pool drain];
    }
}
@end