iphone memory leak with uitableview and sqlite

Question

Hi All,

I am having a problem with what I believe is a memory leak which after some time is causing my app to slow down. I have a sectioned uitableview that has sections of 'movie directors' with rows of thier movies in their particular section. To do this I am calling a data object (and passing it the section header) to return that section's data and populate the section rows. So I am calling that object a few times on the same view(numberOfRowsInSection, cellForRowAtIndexPath, and didSelectRowAtIndexPath) this happens for each section. Looking at Instruments, I believe the leak is coming from getDirectorsMovies:theDirector from Movies.m. Can anyone tell me what I am doing that is causing this leak. Any help would be greatly appreciated, I've been working on this for a few weeks. Below is some code to show what I am doing.

Thanks in advance!!!

    //Movies.h
    #import <Foundation/Foundation.h>
    #import <sqlite3.h>
    #import "Movie.h"

    @interface Movies : NSObject {
    }

    - (NSMutableArray *) getDirectorsMovies:(NSString *)theDirector;

    @end


    //Movies.m  //getDirectorsMovies:(NSString *)theDirector goes to the database, gets the directors movies, and returns them in an array
    #import "Movies.h"

    @implementation Movies

    - (NSMutableArray *) getDirectorsMovies:(NSString *)theDirector
    {
        sqlite3 *database;
        NSString *databaseName = @"Movies.sql";
        NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDir = [documentPaths objectAtIndex:0];
        NSString *databasePath = [documentsDir stringByAppendingPathComponent:databaseName];

         NSMutableArray *theDirectorsMovies = [[NSMutableArray alloc] init];

        if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {
         const char *sqlStatement = "select * from movies where lastname = ? order by lastname, movie";
         sqlite3_stmt *compiledStatement;
         if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
          sqlite3_bind_text(compiledStatement, 1, [theDirector UTF8String], -1, SQLITE_TRANSIENT);
          while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
           NSString *aLastName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
           NSString *aDirector = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];
           NSString *aMovie = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 3)];

           Movie *movie = [[Movie alloc] initWithName:aMovie lastname:aLastName director:aDirector];
           [theDirectorsMovies addObject:movie];
           [movie release];

          }
         }
         sqlite3_finalize(compiledStatement);
        }
        sqlite3_close(database);

        return theDirectorsMovies;
        [theDirectorsMovies release];

    }


    @end

//Calling getDirectorsMovies:(NSString *)theDirector

MoviesAppDelegate *appDelegate = (MoviesAppDelegate *)[[UIApplication sharedApplication] delegate];
Director *director = (Director *)[appDelegate.director objectAtIndex:indexPath.section];//appDelegate.director IS A MSMutableArray defined in the AppDelegate

self.theMovies = nil;//THIS IS A MSMutableArray defined in the AppDelegate
Movies *directorMovies = [[Movies alloc] init];
self.theMovies = [directorMovies getDirectorMovies:director.lastname];
[directorMovies release];

Movie *movie = (Movie *)[theMovies objectAtIndex:indexPath.row];
//do whatever with the data 

[movie release];

Answer 1

You have this:

return theDirectorsMovies;
[theDirectorsMovies release];

Nothing happens after the return statement, so your call to release will never happen. It was for this very reason that AutoreleasePools were invented (and patented). Simply do:

return [theDirectorsMovies autorelease];

And your memory leak will go away.