Pretty universal UITableView / UICollectionView data source implementation in Swift.

SimpleDataSource.swift

import UIKit

class BaseSimpleDataSource<Cell: ReusableView, Collection: CollectionType
    where Collection.Index == Int,
          Collection.Generator.Element: CollectionType,
          Collection.Generator.Element.Index == Int,
          Collection.Generator.Element.Generator.Element == Cell.Model>: NSObject {

    typealias Item = Cell.Model

    var items: Collection? // [[section0item0, section0item1, ...], [section1item0, section1item1, ...], ...]

    func itemByIndexPath(indexPath: NSIndexPath) -> Item {
        return items![indexPath.section][indexPath.row]
    }

    var tuneCell: ((Cell, NSIndexPath) -> ())?

}

class SimpleTableViewDataSource<Cell: ReusableView, Collection: CollectionType
    where Cell: UITableViewCell,
          Collection.Index == Int,
          Collection.Generator.Element: CollectionType,
          Collection.Generator.Element.Index == Int,
          Collection.Generator.Element.Generator.Element == Cell.Model>: BaseSimpleDataSource<Cell, Collection>, UITableViewDataSource {

    // MARK: UITableViewDataSource

    final func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return items?.count ?? 0
    }

    final func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items![section].count
    }

    final func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell: Cell! = tableView.dequeueReusableCellWithIdentifier(Cell.reuseId, forIndexPath: indexPath) as! Cell
        cell.loadModel(itemByIndexPath(indexPath))
        tuneCell?(cell, indexPath)
        return cell
    }

}

class SimpleCollectionViewDataSource<Cell: ReusableView, Collection: CollectionType
    where Cell: UICollectionViewCell,
          Collection.Index == Int,
          Collection.Generator.Element: CollectionType,
          Collection.Generator.Element.Index == Int,
          Collection.Generator.Element.Generator.Element == Cell.Model>: BaseSimpleDataSource<Cell, Collection>, UICollectionViewDataSource {

    // MARK: UICollectionViewDataSource

    final func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return items?.count ?? 0
    }

    final func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return items![section].count
    }

    final func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell: Cell! = collectionView.dequeueReusableCellWithReuseIdentifier(Cell.reuseId, forIndexPath: indexPath) as! Cell
        cell.loadModel(itemByIndexPath(indexPath))
        tuneCell?(cell, indexPath)
        return cell
    }

}

View.swift

import Foundation

protocol View {

    typealias Model

    func loadModel(m: Model)

}

/// Use with `UITableViewCell` and `UICollectionView` subclasses.
protocol ReusableView: View {

    static var reuseId: String { get }

}

extension ReusableView {

    static var reuseId: String {
        get {
            return typeName(self)
        }
    }

}