Objective-C SQLite wrapper

SQLite.h

#import <Foundation/Foundation.h>

@interface SQLiteDatabase: NSObject

- (nullable instancetype)initWithPath:(nonnull NSString *)path;

- (void)executeQuery:(nonnull NSString *)query;
- (void)executeQuery:(nonnull NSString *)query callback:(void(^ _Nullable)(NSDictionary<NSString *, id> * _Nonnull, BOOL * _Nonnull))callback;

@end

@interface SQLiteStatement: NSObject

- (nullable instancetype)initWithQueryTemplate:(nonnull NSString *)template inDatabase:(nonnull SQLiteDatabase *)database;

- (void)execute;
- (void)executeWithParameters:(nullable NSArray *)parameters;
- (void)executeWithCallback:(void(^ _Nullable)(NSDictionary<NSString *, id> * _Nonnull, BOOL * _Nonnull))callback;
- (void)executeWithParameters:(nullable NSArray *)parameters callback:(void(^ _Nullable)(NSDictionary<NSString *, id> * _Nonnull, BOOL * _Nonnull))callback;

@end

SQLite.m

#import "SQLite.h"
#import <sqlite3.h>

@interface SQLiteDatabase ()

@property (assign) sqlite3 *database;

@end

@interface SQLiteStatement ()

@property (assign) sqlite3_stmt *statement;

@end

@implementation SQLiteDatabase

- (instancetype)initWithPath:(NSString *)path {
    self = [super init];
    if (self) {
        if (sqlite3_open([path cStringUsingEncoding:NSUTF8StringEncoding], &_database) != SQLITE_OK) {
            return nil;
        }
    }
    return self;
}

- (void)dealloc {
    if (_database) {
        sqlite3_close(_database);
    }
}

- (void)executeQuery:(NSString *)query {
    [self executeQuery:query callback:nil];
}

- (void)executeQuery:(NSString *)query callback:(void(^)(NSDictionary<NSString *, id> *, BOOL *))callback {
    [[[SQLiteStatement alloc] initWithQueryTemplate:query inDatabase:self] executeWithCallback:callback];
}

@end

@implementation SQLiteStatement

- (instancetype)initWithQueryTemplate:(NSString *)template inDatabase:(SQLiteDatabase *)database {
    self = [super init];
    if (self) {
        if (sqlite3_prepare_v2(database.database, [template cStringUsingEncoding:NSUTF8StringEncoding], -1, &_statement, NULL) != SQLITE_OK) {
            return nil;
        }
    }
    return self;
}

- (void)dealloc {
    if (_statement) {
        sqlite3_finalize(_statement);
    }
}

- (void)execute {
    [self executeWithParameters:nil callback:nil];
}

- (void)executeWithParameters:(NSArray *)parameters {
    [self executeWithParameters:parameters callback:nil];
}

- (void)executeWithCallback:(void(^)(NSDictionary<NSString *, id> *, BOOL *))callback {
    [self executeWithParameters:nil callback:callback];
}

- (void)executeWithParameters:(NSArray *)parameters callback:(void(^)(NSDictionary<NSString *, id> *, BOOL *))callback {
    sqlite3_reset(_statement);
    for (int i = 0; i < parameters.count; i++) {
        id parameter = parameters[i];
        if ([parameter isKindOfClass:[NSNull class]]) {
            sqlite3_bind_null(_statement, i+1);
        } else if ([parameter isKindOfClass:[NSString class]]) {
            sqlite3_bind_text(_statement, i+1, [parameter cStringUsingEncoding:NSUTF8StringEncoding], -1, SQLITE_STATIC);
        } else if ([parameter isKindOfClass:[NSData class]]) {
            sqlite3_bind_blob(_statement, i+1, [parameter bytes], [parameter length], NULL);
        } else if ([parameter isKindOfClass:[NSNumber class]]) {
            switch ([parameter objCType][0]) {
                case 'd':
                case 'f':
                    sqlite3_bind_double(_statement, i+1, [parameter doubleValue]);
                    break;
                default:
                    sqlite3_bind_int64(_statement, i+1, [parameter longLongValue]);
                    break;
            }
        }
    }
    
    BOOL stop = NO;
    int columnCount = sqlite3_column_count(_statement);
    while (!stop && sqlite3_step(_statement) == SQLITE_ROW && callback) {
        NSMutableDictionary<NSString *, id> *row = [[NSMutableDictionary alloc] init];
        for (int i = 0; i < columnCount; i++) {
            NSString *key = [[NSString alloc] initWithCString:sqlite3_column_name(_statement, i) encoding:NSUTF8StringEncoding];
            id value = nil;
            switch (sqlite3_column_type(_statement, i)) {
                case SQLITE_NULL: {
                    value = [NSNull null];
                } break;
                
                case SQLITE_INTEGER: {
                    value = [[NSNumber alloc] initWithLongLong:sqlite3_column_int64(_statement, i)];
                } break;
                    
                case SQLITE_FLOAT: {
                    value = [[NSNumber alloc] initWithDouble:sqlite3_column_double(_statement, i)];
                } break;
                                
                case SQLITE_BLOB: {
                    int length = sqlite3_column_bytes(_statement, i);
                    const void *bytes = sqlite3_column_blob(_statement, i);
                    value = [[NSData alloc] initWithBytes:bytes length:length];
                } break;
                                
                case SQLITE3_TEXT: {
                    int length = sqlite3_column_bytes(_statement, i);
                    const void *bytes = sqlite3_column_blob(_statement, i);
                    value = [[NSString alloc] initWithBytes:bytes length:length encoding:NSUTF8StringEncoding];
                } break;
            }
            row[key] = value;
        }
        callback(row, &stop);
    }
}

@end