Basic Objective-C RocksDB Wrapper (w/ KVC)

AXDatabase.h

//
//  AXDatabase.h
//  YoDogg
//
//  Created by Alexander Böhn on 2/19/17.
//  Copyright © 2017 Alexander Böhn. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface AXDatabase : NSObject {}

- (instancetype) initWithDatabase:(NSString*)dbFileName;

@end

@interface AXDatabase (NSKeyValueCoding)

- (void) setValue:(id)value forKey:(NSString*)key;
- (void) removeValueForKey:(NSString*)key;
- (id) valueForKey:(NSString*)key;

- (void) setObject:(id)object forKey:(NSString*)key;
- (void) removeObjectForKey:(NSString*)key;
- (id) objectForKey:(NSString*)key;

- (NSArray*) allObjects;
- (NSUInteger) count;

- (id) objectForKeyedSubscript:(NSString*)key;
- (void) setObject:(id)object forKeyedSubscript:(NSString*)key;

@end

AXDatabase.mm

//
//  AXDatabase.mm
//  YoDogg
//
//  Created by Alexander Böhn on 2/19/17.
//  Copyright © 2017 Alexander Böhn. All rights reserved.
//

#import "AXDatabase.h"

#include <string>
#include "rocksdb/db.h"

@interface AXDatabase ()

@property (nonatomic, unsafe_unretained) rocksdb::DB* rocks;

@end


@implementation AXDatabase

- (instancetype) initWithDatabase:(NSString*)dbFileName {
    self = [super init];
    rocksdb::Options options;
    options.create_if_missing = true;
    rocksdb::Status status = rocksdb::DB::Open(options, [dbFileName UTF8String], &_rocks);
    NSLog(@"[AXDatabase initWithDatabase:%s] (status: %s)",
          [dbFileName UTF8String],
          status.ok() ? "OK" : "Not OK");
    return self;
}

- (void) dealloc {
    delete _rocks;
}

#pragma mark - Public API: NSKeyValueCoding

- (void) setValue:(id)value forKey:(NSString*)key {
    NSData* data = [NSKeyedArchiver archivedDataWithRootObject:value];
    if (data == nil) { return; }
    std::string sval((char const*)data.bytes, data.length);
    rocksdb::Status status = self.rocks->Put(rocksdb::WriteOptions(), [key UTF8String], sval);
    rocksdb::Status flushed = self.rocks->Flush(rocksdb::FlushOptions());
}

- (void) removeValueForKey:(NSString*)key {
    rocksdb::Status status = self.rocks->Delete(rocksdb::WriteOptions(), [key UTF8String]);
}

- (id) valueForKey:(NSString*)key {
    std::string sval;
    rocksdb::Status status = self.rocks->Get(rocksdb::ReadOptions(), [key UTF8String], &sval);
    if (!status.ok()) { return nil; }
    NSData* data = [[NSData alloc] initWithBytes:sval.data() length:sval.size()];
    if (data == nil) { return nil; }
    return [NSKeyedUnarchiver unarchiveObjectWithData:data];
}

- (void) setObject:(id)object forKey:(NSString*)key {
    NSData* data = [NSKeyedArchiver archivedDataWithRootObject:object];
    if (data == nil) { return; }
    std::string sval((char const*)data.bytes, data.length);
    rocksdb::Status status = self.rocks->Put(rocksdb::WriteOptions(), [key UTF8String], sval);
    rocksdb::Status flushed = self.rocks->Flush(rocksdb::FlushOptions());
}

- (void) removeObjectForKey:(NSString*)key {
    rocksdb::Status status = self.rocks->Delete(rocksdb::WriteOptions(), [key UTF8String]);
}

- (id) objectForKey:(NSString*)key {
    std::string sval;
    rocksdb::Status status = self.rocks->Get(rocksdb::ReadOptions(), [key UTF8String], &sval);
    if (!status.ok()) { return nil; }
    NSData* data = [[NSData alloc] initWithBytes:sval.data() length:sval.size()];
    if (data == nil) { return nil; }
    return [NSKeyedUnarchiver unarchiveObjectWithData:data];
}

- (NSArray*) allObjects {
    rocksdb::Iterator* it = self.rocks->NewIterator(rocksdb::ReadOptions());
    NSMutableArray* out = [[NSMutableArray alloc] init];
    for (it->SeekToFirst(); it->Valid(); it->Next()) {
        std::string sval(it->value().ToString());
        NSData* data = [[NSData alloc] initWithBytes:sval.data() length:sval.size()];
        if (data != nil) {
            [out addObject:[NSKeyedUnarchiver unarchiveObjectWithData:data]];
        }
    }
    delete it;
    return [NSArray arrayWithArray:out];
}

- (NSUInteger) count {
    uint64_t cnt;
    bool status = self.rocks->GetIntProperty(rocksdb::DB::Properties::kEstimateNumKeys, &cnt);
    if (status) {
        return cnt;
    }
    return 0;
}

- (id) objectForKeyedSubscript:(NSString*)key {
    std::string sval;
    rocksdb::Status status = self.rocks->Get(rocksdb::ReadOptions(), [key UTF8String], &sval);
    if (!status.ok()) { return nil; }
    NSData* data = [[NSData alloc] initWithBytes:sval.data() length:sval.size()];
    if (data == nil) { return nil; }
    return [NSKeyedUnarchiver unarchiveObjectWithData:data];
}

- (void) setObject:(id)object forKeyedSubscript:(NSString*)key {
    NSData* data = [NSKeyedArchiver archivedDataWithRootObject:object];
    if (data == nil) { return; }
    std::string sval((char const*)data.bytes, data.length);
    rocksdb::Status status = self.rocks->Put(rocksdb::WriteOptions(), [key UTF8String], sval);
    rocksdb::Status flushed = self.rocks->Flush(rocksdb::FlushOptions());
}

@end