Database.m

gistfile1.txt

#import "Database.h"

@implementation Database

static Database *db = nil;
static sqlite3 *_database = nil;

#pragma mark -
#pragma mark Singleton methods

+(Database *) sharedDatabase {
	@synchronized(self)
    {
        if (db == nil)
			db = [[Database alloc] init];
		
    }
    return db;
}

+(id) allocWithZone:(NSZone *)zone {
	@synchronized (self) {
		if (db == nil) {
			return [super allocWithZone:zone];
		}
	}
	return nil;
}

- (id)copyWithZone:(NSZone *)zone{
    return self;
}

#pragma mark -
#pragma mark Private Methods

// Returns a reference to the database.
sqlite3 *Pc2MacDatabase() {
    if (_database == nil) {
        // First, test for existence.
		NSError *error;
		NSFileManager *fileManager = [NSFileManager defaultManager];
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:kDatabaseFile];
        
		if ([fileManager fileExistsAtPath:writableDBPath] == NO) {
            // Database file doesnt exists. Copy the database at writable path (documents directory).
			NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:kDatabaseFile];
			
			[fileManager removeItemAtPath:writableDBPath error:nil];
			
			BOOL databaseCopied = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
			if (!databaseCopied) {
				// Handle the error...
			}
        }else {
			// Open the database. The database was prepared outside the application.
			if (sqlite3_open([writableDBPath UTF8String], &_database) != SQLITE_OK) {
				// Even though the open failed, call close to properly clean up resources.
				sqlite3_close(_database);
				_database = nil;
				// Additional error handling, as appropriate...
			}
		}
    }
    return _database;
}

#pragma mark -
#pragma mark Closing database

// Close the database. This should be called when the application terminates.
void ClosePc2MacDatabase() {
    if (_database == nil) return;
    // Close the database.
    if (sqlite3_close(_database) != SQLITE_OK) {
        // Handle the error...
    }
    _database = nil;
}

@end