内存泄漏-mac，xcode

遇到这么一个泄漏事件：

环境：Xcode 4.2.1，mac 10.7.1

先看代码：

.h

@interface TableController : UITableViewController

@property (nonatomic ,retain) NSArray *DataSource;

@end

.m

#import "TableController.h"
#import "TableView.h"
#import "CellItem.h"
#import "Et.h"

#import "DetailController.h"

@implementation TableController

@synthesize DataSource = _DataSource;

- (void)defaultValues
{
    self->_DataSource = nil;
}

- (void)loadDatasFromDB
{
    if (self->_DataSource)
        [self->_DataSource release];
    self->_DataSource = nil;

    // load data from db
    // test code b
    NSMutableArray *mutDatas = [[NSMutableArray alloc] init];
    
    for (int i=0; i<10; i++)
    {
        Et *item = [[Et alloc] init];
        item.ID = i;
        item.RecordDate = [NSDate date];
        item.Content = [NSString stringWithFormat:@"%d,%@",i ,item.RecordDate];
        
        [mutDatas addObject:item];
        
        [item release];
    }
    
    self->_DataSource = [[NSArray alloc] initWithArray:mutDatas];
    [mutDatas removeAllObjects];
    [mutDatas release];
    mutDatas = nil;
    // test code e
}

- (void)gotoView:(id)sender
{
    DetailController *detailViewController = [[DetailController alloc] init];
    [self.navigationController pushViewController:detailViewController animated:YES];
    [detailViewController release];
}

- (void)navSetting
{
    self.navigationItem.title = @"Title";
    
    UIBarButtonItem *btnSettings
    = [[UIBarButtonItem alloc] initWithTitle:@"+"
                                       style:UIBarButtonItemStyleBordered
                                      target:self
                                      action:@selector(gotoView:)];
    self.navigationItem.rightBarButtonItem = btnSettings;
    [btnSettings release];
}

- (id)init
{
    self = [super init];
    if (self)
    {
        [self defaultValues];
    [self loadDatasFromDB];/// ------注意：LeakProblem
    }
    
    return self;
}

- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];
    if (self) {
        // Custom initialization
        [self defaultValues];
    [self loadDatasFromDB];/// ------注意：LeakProblem
    }
    return self;
}

- (void)dealloc
{
    if (self.DataSource)
        [self->_DataSource release];
    
    [self defaultValues];
    
    [super dealloc];
}

- (void)didReceiveMemoryWarning
{
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
    
    // Release any cached data, images, etc that aren't in use.
}

#pragma mark - View lifecycle

- (void)loadView
{    
    TableView *v = [[TableView alloc] init];
    v.dataSource = self;
    v.delegate = self;
    self.view = v;
    [v release];
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Uncomment the following line to preserve selection between presentations.
    // self.clearsSelectionOnViewWillAppear = NO;
 
    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem;
    [self navSetting];
    
    [self loadDatasFromDB];/// ------注意：LeakProblem 修复方式
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
    
    if (self->_DataSource)
        [self->_DataSource release];
    self->_DataSource = nil;
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
}

- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
//#warning Potentially incomplete method implementation.
    // Return the number of sections.
    if (self.DataSource)
        return 1;
    return 0;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
//#warning Incomplete method implementation.
    // Return the number of rows in the section.
    if (self.DataSource)
        return self.DataSource.count;
    return 0;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) 
    {
        cell = [[[CellItem alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
        
        if (self.DataSource)
        {
            if (self.DataSource.count > indexPath.row)
            {
                id cellData = [self.DataSource objectAtIndex:indexPath.row];
                
                if ([cellData isKindOfClass:[Et class]])
                {
                    Et *etItem = (Et *)cellData;
                    
                    CellItem *c = (CellItem *)cell;
                    
                    if (etItem.RecordDate)
                    {
                        NSRange range;
                        range.location = 0;
                        range.length = 10;
                        [c.LblRecordDate setText:[[NSString stringWithFormat:@"%@" ,etItem.RecordDate] substringWithRange:range]];
                    }
                    
                    if (etItem.Content)
                    {
                        NSRange range;
                        range.location = 0;
                        if (etItem.Content.length >10)
                            range.length = 10;
                        else
                            range.length = etItem.Content.length;
                        [c.LblSimpleContent setText:[etItem.Content substringWithRange:range]];
                    }
                    
                    if (c.LblRecordDate)
                        [c addSubview:c.LblRecordDate];
                    
                    if (c.LblSimpleContent)
                        [c addSubview:c.LblSimpleContent];
                }
                
            }
        }
    }
    
    return cell;
}

/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the specified item to be editable.
    return YES;
}
*/

/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
    }   
    else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }   
}
*/

/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
}
*/

/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the item to be re-orderable.
    return YES;
}
*/

#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Navigation logic may go here. Create and push another view controller.
    /*
     <#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:@"<#Nib name#>" bundle:nil];
     // ...
     // Pass the selected object to the new view controller.
     [self.navigationController pushViewController:detailViewController animated:YES];
     [detailViewController release];
     */
    
    NSLog(@"%d" ,indexPath.row);
}

@end

代码中/// ------注意：LeakProblem和/// ------注意：LeakProblem 修复方式 两处语句互斥，不同时存在

保留/// ------注意：LeakProblem，删除/// ------注意：LeakProblem 修复方式
使用Analyze工具分析，没有泄漏代码
使用Profile工具分析，会出现loadDatasFromDB中一个NSArray数组以及10个内容泄漏

在调试中，尝试关闭loadDatasFromDB，在applicationDelegate.m中定义一个数组，赋予给属性Datasource，分别用上述工具再次分析，发现无泄漏

思考再三，移出在init中对loadDatasFromDB函数的调用，在viewDidLoad中调用
就是：
删除/// ------注意：LeakProblem，保留/// ------注意：LeakProblem 修复方式
又用上述工具分析，无泄漏

至于为什么第一种方式会导致profile泄漏，暂时没有找到合适说法

晚点再用xcode4.3.2试下【尝试了，和上述结论一样】

2012-06-28