PGActivity.m

/* Copyright © 2010, The Sequential Project
All rights reserved.

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      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 name of the the Sequential Project nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE SEQUENTIAL PROJECT ''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 SEQUENTIAL PROJECT 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
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#import "PGActivity.h"

static PGActivity *PGApplicationActivity;

@interface PGActivity(Private)

- (void)_addChildActivity:(PGActivity *)activity;
- (void)_removeChildActivity:(PGActivity *)activity;
- (void)_prioritizeChildActivity:(PGActivity *)activity;

@end

@implementation PGActivity

#pragma mark +PGActivity

+ (id)applicationActivity
{
	return PGApplicationActivity;
}

#pragma mark +NSObject

+ (void)initialize
{
	if(!PGApplicationActivity) PGApplicationActivity = [[self alloc] init];
}

#pragma mark -PGActivity

- (id)initWithOwner:(NSObject<PGActivityOwner> *)owner
{
	if((self = [self init])) {
		_owner = owner;
	}
	return self;
}
- (NSObject<PGActivityOwner> *)owner
{
	@synchronized(self) {
		return _owner;
	}
	return nil;
}
- (PGActivity *)parentActivity
{
	@synchronized(self) {
		return _parentActivity;
	}
	return nil;
}
- (void)setParentActivity:(PGActivity *)activity
{
	@synchronized(self) {
		if(activity == _parentActivity) return;
		[_parentActivity _removeChildActivity:self];
		_parentActivity = activity;
		[_parentActivity _addChildActivity:self];
	}
}
- (NSString *)activityDescription
{
	NSString *const desc = [[self owner] descriptionForActivity:self];
	return desc ? desc : @"";
}
- (CGFloat)progress
{
	NSObject<PGActivityOwner> *const owner = [self owner];
	return owner ? [owner progressForActivity:self] : -1.0f;
}
- (BOOL)isActive
{
	if([self progress] >= 0.0f) return YES;
	@synchronized(self) {
		for(PGActivity *const child in _childActivities) if([child isActive]) return YES;
	}
	return NO;
}
- (NSArray *)childActivities:(BOOL)activeOnly
{
	NSMutableArray *activeChildren = nil;
	@synchronized(self) {
		if(activeOnly) {
			activeChildren = [NSMutableArray arrayWithCapacity:[_childActivities count]];
			for(PGActivity *const child in _childActivities) if([child isActive]) [activeChildren addObject:child];
		} else activeChildren = [[_childActivities copy] autorelease];
	}
	return activeChildren;
}

#pragma mark -

- (IBAction)cancel:(id)sender
{
	@synchronized(self) {
		[self setParentActivity:nil];
		[[[_childActivities copy] autorelease] makeObjectsPerformSelector:@selector(cancel:) withObject:sender];
	}
	[[self owner] cancelActivity:self];
}
- (IBAction)prioritize:(id)sender
{
	@synchronized(self) {
		[_parentActivity _prioritizeChildActivity:self];
	}
}
- (void)invalidate
{
	@synchronized(self) {
		_owner = nil;
		[self setParentActivity:nil];
	}
}

#pragma mark -PGActivity(Private)

- (void)_addChildActivity:(PGActivity *)activity
{
	@synchronized(self) {
		NSUInteger const i = [_childActivities indexOfObjectIdenticalTo:activity];
		NSParameterAssert(NSNotFound == i);
		[_childActivities addObject:activity];
	}
}
- (void)_removeChildActivity:(PGActivity *)activity
{
	@synchronized(self) {
		[_childActivities removeObjectIdenticalTo:activity];
	}
}
- (void)_prioritizeChildActivity:(PGActivity *)activity
{
	@synchronized(self) {
		NSUInteger const i = [_childActivities indexOfObjectIdenticalTo:activity];
		NSParameterAssert(NSNotFound != i);
		[_childActivities removeObjectAtIndex:i];
		[_childActivities insertObject:activity atIndex:0];
		[_parentActivity _prioritizeChildActivity:self];
	}
}

#pragma mark -NSObject

- (id)init
{
	if((self = [super init])) {
		_childActivities = [[NSMutableArray alloc] init];
	}
	return self;
}
- (void)dealloc
{
	[[[_childActivities copy] autorelease] makeObjectsPerformSelector:@selector(setParentActivity:) withObject:nil];
	[_childActivities release];
	[super dealloc];
}

@end

@implementation NSObject(PGActivityOwner)

- (CGFloat)progressForActivity:(PGActivity *)activity
{
	return -1.0f;
}
- (void)cancelActivity:(PGActivity *)activity {}

@end