sqlite3 - stringWithUTF8String泄露了！

Question

如果有人能帮我解决我的漏水问题，我将不胜感激。泄漏发生在: aImage、aCategory、aDescription、category和categories。我在dealloc中释放它们，但显然这还不够：

-(void) readListFromDatabase:(char *) sqlStatement {
    // Setup some globals
    databaseName = @"mydatabase.sql";

    // Get the path to the documents directory and append the databaseName
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDir = [documentPaths objectAtIndex:0];
    databasePath = [documentsDir stringByAppendingPathComponent:databaseName];

    // Setup the database object
    sqlite3 *database;

    // Init the categories Array
    categories = [[NSMutableArray alloc] init];

    // Open the database from the users filessytem
    if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
        // Setup the SQL Statement and compile it for faster access
        sqlite3_stmt *compiledStatement;
        if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
            // Loop through the results and add them to the feeds array
            while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
                // Read the data from the result row
                aImage = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 0)];
                aCategory = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
                aDescription = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];

                // Create a new category object with the data from the database             
                category=[[Category alloc] initWithName:aImage category_name:aCategory description_text:aDescription];

                // Add the category object to the categories Array
                [categories addObject:category];

                [category release];
            }
        }
        // Release the compiled statement from memory
        sqlite3_finalize(compiledStatement);
    }
    sqlite3_close(database);

}

- (void)dealloc {
    [databaseName release];
    [databasePath release];
    [categories release];
    [aImage release];
    [aCategory release];
    [aDescription release];
    [category release];


    [super dealloc];
}

Answer 1

如果多次调用该方法，则字符串将泄漏，因为您需要释放以前的值。您还会在dealloc中过度释放字符串，因为您从未保留过它们。你应该像这样写作业：

[aImage release];
aImage = [[NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 0)] retain];

这些字符串可能泄漏的唯一另一种方式是，如果您从线程调用此方法，并且您没有创建自动释放池。

如果从新线程调用该方法，则需要一个自动释放池：

- (void)myThreadFunction {
    NSAutoReleasePool *pool = [[NSAutoReleasePool alloc] init];
    try {
        // ...
        [self readListFromDatabase:whatever];
        // ...
    } @finally {
        [pool release];
    }

}

Answer 2

您发布的方法是否在同一对象上被多次调用？如果是，则第一次调用的类别将泄漏，因为每次调用readListFromDatabase:时都会覆盖该类别。尝试：

// Init the categories Array
[categories release];
categories = [[NSMutableArray alloc] init];

Answer 3

当我在循环中包含aImage自动释放时，为什么应用程序终止(如果是aImage释放，它也终止)？