Vellum

• Swift 5.0 or higher
• iOS 9.3 or higher

Vellum is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'Vellum'

• Add it using XCode menu File > Swift Package > Add Package Dependency
• Add https://github.com/hainayanda/Vellum.git as Swift Package URL
• Set rules at version, with Up to Next Major option and put 1.2.3 as its version
• Click next and wait

Add as your target dependency in Package.swift

dependencies: [
    .package(url: "https://github.com/hainayanda/Vellum.git", .upToNextMajor(from: "1.2.3"))
]

Use it in your target as Vellum

 .target(
    name: "MyModule",
    dependencies: ["Vellum"]
)

Then run swift build to build the dependency before you use it

Nayanda Haberty, hainayanda@outlook.com

Vellum is available under the MIT license. See the LICENSE file for more info.

Vellum is using LRU Algorithm. It contains 2 type of storage which is Memory Storage and Disk Storage. Both sizes can be assigned manually.

1. Store data to Memory Storage
2. If Memory Storage is full, it will remove the oldest accessed data from memory until space is enough for new data
3. Data stored in the memory
4. Store data to Disk Storage
5. If Disk Storage is full, it will remove the oldest accessed data from memory until space is enough for new data
6. Data stored to the disk

1. Find data from the Memory Storage
2. If the data exist, it will return the data and the step ended
3. If the data do not exist in the memory, it will try to find data from Disk Storage
4. If the data exist, it will store the data to the Memory Storage for future faster use and return the data and the step ended
5. If the data do not exist, it will return nil

All you need to do is just get the ArchiveManager from factory and store your object which implement Archivable and Codable or using typealias ArchiveCodable which is the same:

let archives = try! ArchivesFactory.shared.archives(
    for: MyArchivable.self,
    trySetMaxMemorySize: 10.megaByte, 
    trySetMaxDiskSize: 20.megaByte
)

// will insert object
archives.record(myObject)

let object = archives.access(archiveWithKey: "object_key")

Archivable actually is just a protocol that has methods to convert an object to data or vice versa. Archivable make sure the object has keys too:

class User: Archivable {
    
    var primaryKey: String { userName }
    var userName: String = ""
    var fullName: String = ""
    var age: Int = 0
    
    func archive() throws -> Data {
        // do something to convert the object to Data
    }
    
    static func deArchive(fromData data: Data) throws -> Archivable {
        // do something to convert the data to object
    }
}

If your object is Codable, just add Archivable or using typealias ArchiveCodable which is the same, your object will have those methods automatically. You just need to add primaryKey property you want as the primary key as long as the value is String:

struct User: Codable, Archivable {
    var primaryKey: String { userName }
    var userName: String
    var fullName: String
    var age: Int
}

To get ArchiveManager, you can use ArchivesFactory. You can assign the maximum size in bytes for memory size and disk size. But keep in mind, the size will only apply on the first creation of the ArchiveManager, If the cache manager is already created, then the memory size and disk size is ignored. If you don't assign the memory size or disk size, it will use the default value which is 1 megabyte for memory and 2 megabyte disk size:

let archives = try! ArchivesFactory.shared.archives(
    for: User.self, 
    trySetMaxMemorySize: 10.kiloByte, 
    trySetMaxDiskSize: 20.kiloByte
)

// or not explicit
let sameArchives: ArchiveManager<User> = try! ArchivesFactory.shared.archives( 
    trySetMaxMemorySize: 10.kiloByte, 
    trySetMaxDiskSize: 20.kiloByte
)

the ArchiveManager have some usable methods and property which are:

• var maxSize: Int { get } to get maximum size of the cache
• var currentSize: Int { get } to get current used size of the cache
• func latestAccessedTime(for key: String) -> Date? to get the latest time the object with same key accessed
• func deleteAllInvalidateArchives(invalidateTimeInterval: TimeInterval) to remove all object older than time interval
• func record(_ object: Archive) to insert object
• func update(_ object: Archive) to update existing object, or insert if have none
• func access(archiveWithKey key: String) -> Archive? to get object with given key
• func accessAll(limitedBy limit: Int) -> [Archive] to get all object limited by limit
• func accessAll() -> [Archive] to get all object stored in cache
• func delete(archiveWithKey key: String) to delete object with given key
• func deleteAll() to remove all object from cache
• func process(queries: [Query<Archive>]) -> [Archive] to process query. This will be disucessed later

You can do a query from the cache. there are 3 types of query which are:

• QueryFinder to find the object/results by its properties
• QuerySorter to sort the results by its properties
• QueryLimiter to limit the results by limit

All Query can be combined and will executed sequentially:

let results = userCache.findWhere { archive in
    archive.userName(.contains("premium"))
        .fullName(.isNotEqual(nil))
}
.getResults()

The code above will find all users in the cache whose userName contains "premium" and its fullName is not nill. The result is an array of User

let results = userCache.sorted { by in 
    by.age(.ascending)
        .fullName(.descending)
}
.getResults()

The code above will get all users in cache and sorted it by its age ascendingly and then its fullName descendingly. The results are sorted array of User

You can add the limit too

let results = userCache.sorted { by in 
    by.age(.ascending)
        .fullName(.descending)
}
.limitResults(by: 10)
.getResults()

The code above will limit the results maximum of just 10

You can even combine the query if you want:

let results = userCache.findWhere { archive in
    archive.userName(.contains("premium"))
        .fullName(.isNotEqual(nil))
}
.sorted { by in 
    by.age(.ascending)
        .fullName(.descending)
}
.limitResults(by: 10)
.getResults()

The code above will find all users in the cache whose userName contains "premium" and its fullName is not nill, then sort it by its age ascendingly and then its fullName descendingly. The results are limited by 10.

here are the list of finder that can be used with QueryFinder:

• contains(string: ) match if string property contains given string
• matches(regex: ) match if string property matches with given regex
• contains(with: ) match if collection property is contains given element
• contains(atLeastOne: ) match if collection property contains at least one of given element
• contains(all: ) match if collection property contains all given element
• countEqual(with: ) match if collection property count equal with given number
• countGreater(than: ) match if collection property count greater than given number
• countLess(than: ) match if collection property count less than given number
• countGreaterOrEqual(with: ) match if collection property count greater than or equal with given number
• countLessOrEqual(with: ) match if collection property count greater than or equal with given number
• isEqual(with: ) match if property equal with given value
• isNotEqual(with: ) match if property not equal with given value
• greater(than: ) match if property greater than given value
• less(than: ) match if property less than given value
• greaterOrEqual(with: ) match if property greater than or equal with given value
• lessOrEqual(with: ) match if property less than or equal with given value

if you want to validate manually, you can just use isValid(_ validator: (Property) -> Bool):

let results = userCache.findWhere { archive in
    archive.userName(.isValid { $0.contains("premium") })
}
.getResults()

You could use Archived property wrapper to wrapped any property so if it assigned it will automatically store those properties into ArchiveManager:

@Archived var user: User?

if you want the property to have an initial value based on the given primary key, just pass the key:

@Archived(initialPrimaryKey: "some") var user: User?

Code above will try to get the user with the given key at first property load.