Add basic support for UICollectionView

No layout, registration is done every dequeue, many other issues :)

Composed.xcodeproj/project.pbxproj

@@ -89,6 +89,10 @@
 		D941140F2297F4FA00077F90 /* ArraySection.swift in Sources */ = {isa = PBXBuildFile; fileRef = D941140E2297F4FA00077F90 /* ArraySection.swift */; };
 		D94114112297F86100077F90 /* SectionProviderMapper.swift in Sources */ = {isa = PBXBuildFile; fileRef = D94114102297F86100077F90 /* SectionProviderMapper.swift */; };
 		D9D7DCBD22981094001DA4D9 /* SectionProviderMapper+Spec.swift in Sources */ = {isa = PBXBuildFile; fileRef = D9D7DCBC22981094001DA4D9 /* SectionProviderMapper+Spec.swift */; };
+		D9D7DCBF22985C44001DA4D9 /* CollectionViewSectionProviderCoordinator.swift in Sources */ = {isa = PBXBuildFile; fileRef = D9D7DCBE22985C44001DA4D9 /* CollectionViewSectionProviderCoordinator.swift */; };
+		D9D7DCC122985F04001DA4D9 /* SectionsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D9D7DCC022985F04001DA4D9 /* SectionsViewController.swift */; };
+		D9D7DCC422986949001DA4D9 /* SectionCollectionUIConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D9D7DCC322986949001DA4D9 /* SectionCollectionUIConfiguration.swift */; };
+		D9D7DCC62298695E001DA4D9 /* CollectionUIConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D9D7DCC52298695E001DA4D9 /* CollectionUIConfiguration.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -219,6 +223,10 @@
 		D941140E2297F4FA00077F90 /* ArraySection.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ArraySection.swift; sourceTree = "<group>"; };
 		D94114102297F86100077F90 /* SectionProviderMapper.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SectionProviderMapper.swift; sourceTree = "<group>"; };
 		D9D7DCBC22981094001DA4D9 /* SectionProviderMapper+Spec.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "SectionProviderMapper+Spec.swift"; sourceTree = "<group>"; };
+		D9D7DCBE22985C44001DA4D9 /* CollectionViewSectionProviderCoordinator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CollectionViewSectionProviderCoordinator.swift; sourceTree = "<group>"; };
+		D9D7DCC022985F04001DA4D9 /* SectionsViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SectionsViewController.swift; sourceTree = "<group>"; };
+		D9D7DCC322986949001DA4D9 /* SectionCollectionUIConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SectionCollectionUIConfiguration.swift; sourceTree = "<group>"; };
+		D9D7DCC52298695E001DA4D9 /* CollectionUIConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CollectionUIConfiguration.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -275,6 +283,7 @@
 			isa = PBXGroup;
 			children = (
 				540221222195C44F00F0E173 /* AppDelegate.swift */,
+				D9D7DCC022985F04001DA4D9 /* SectionsViewController.swift */,
 				54BAB15D221497FA0064CE51 /* GlobalHeaderView.swift */,
 				54BAB15F221498000064CE51 /* GlobalHeaderView.xib */,
 				54BAB1632214D05C0064CE51 /* GlobalFooterView.swift */,
@@ -440,10 +449,21 @@
 				D941140C2297F40500077F90 /* ComposedSectionProvider.swift */,
 				D941140E2297F4FA00077F90 /* ArraySection.swift */,
 				D94114102297F86100077F90 /* SectionProviderMapper.swift */,
+				D9D7DCBE22985C44001DA4D9 /* CollectionViewSectionProviderCoordinator.swift */,
+				D9D7DCC222986942001DA4D9 /* UI */,
 			);
 			path = Sections;
 			sourceTree = "<group>";
 		};
+		D9D7DCC222986942001DA4D9 /* UI */ = {
+			isa = PBXGroup;
+			children = (
+				D9D7DCC52298695E001DA4D9 /* CollectionUIConfiguration.swift */,
+				D9D7DCC322986949001DA4D9 /* SectionCollectionUIConfiguration.swift */,
+			);
+			path = UI;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXHeadersBuildPhase section */
@@ -598,6 +618,7 @@
 				54BAB15E221497FA0064CE51 /* GlobalHeaderView.swift in Sources */,
 				54BAB1642214D05C0064CE51 /* GlobalFooterView.swift in Sources */,
 				548A8B702214FA2800C0A276 /* BackgroundView.swift in Sources */,
+				D9D7DCC122985F04001DA4D9 /* SectionsViewController.swift in Sources */,
 				540221232195C45000F0E173 /* AppDelegate.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -626,13 +647,15 @@
 				54A17324225CC72900A7D7FD /* AggregateDataSource.swift in Sources */,
 				54A17334225CC72900A7D7FD /* FlowLayout+Metrics.swift in Sources */,
 				54A17330225CC72900A7D7FD /* FlowLayoutInvalidationContext.swift in Sources */,
+				D9D7DCBF22985C44001DA4D9 /* CollectionViewSectionProviderCoordinator.swift in Sources */,
 				54A17325225CC72900A7D7FD /* CollectionDataSource.swift in Sources */,
 				54A17331225CC72900A7D7FD /* FlowLayout+Helpers.swift in Sources */,
 				54A17322225CC72900A7D7FD /* DataStore.swift in Sources */,
 				54A1731E225CC72900A7D7FD /* BasicDataSource.swift in Sources */,
 				54A1732A225CC72900A7D7FD /* CollectionUIProvidingDataSource.swift in Sources */,
 				54A1732F225CC72900A7D7FD /* NibLoadable.swift in Sources */,
 				54A17338225CC72900A7D7FD /* Snap.swift in Sources */,
+				D9D7DCC62298695E001DA4D9 /* CollectionUIConfiguration.swift in Sources */,
 				54A1731C225CC72900A7D7FD /* SegmentedDataSource.swift in Sources */,
 				D941140F2297F4FA00077F90 /* ArraySection.swift in Sources */,
 				54A17339225CC72900A7D7FD /* DataSourceViewController.swift in Sources */,
@@ -647,6 +670,7 @@
 				54A17337225CC72900A7D7FD /* DataSourceHeaderFooterView.swift in Sources */,
 				54A1731F225CC72900A7D7FD /* ComposedDataSource.swift in Sources */,
 				54A1733B225CC72900A7D7FD /* CollectionUIViewProvider.swift in Sources */,
+				D9D7DCC422986949001DA4D9 /* SectionCollectionUIConfiguration.swift in Sources */,
 				54A1732E225CC72900A7D7FD /* CollectionUISizingStrategy.swift in Sources */,
 				54A1732B225CC72900A7D7FD /* DataSourceChangeSet.swift in Sources */,
 				54A17320225CC72900A7D7FD /* ArrayDataStore.swift in Sources */,

Composed/Core/Sections/ArraySection.swift

@@ -1,10 +1,14 @@
 import Foundation
 
-public final class ArraySection<Element>: MutableSection {
+open class ArraySection<Element>: MutableSection {
 
     public weak var updateDelegate: SectionUpdateDelegate?
 
-    public var elements: [Element] = []
+    public var elements: [Element]
+
+    public init(elements: [Element] = []) {
+        self.elements = elements
+    }
 
     public func element(at index: Int) -> Element {
         return elements[index]

Composed/Core/Sections/CollectionViewSectionProviderCoordinator.swift

@@ -0,0 +1,60 @@
+import UIKit
+
+public final class CollectionViewSectionProviderCoordinator: NSObject, UICollectionViewDataSource, SectionProviderMapperDelegate {
+
+    private let mapper: SectionProviderMapper
+    private let collectionView: UICollectionView
+
+    public init(collectionView: UICollectionView, sectionProvider: SectionProvider) {
+        self.collectionView = collectionView
+        mapper = SectionProviderMapper(globalProvider: sectionProvider)
+
+        super.init()
+
+        collectionView.dataSource = self
+    }
+
+    // MARK: - SectionProviderMapperDelegate
+
+    public func sectionProviderMapper(_ sectionProviderMapper: SectionProviderMapper, didInsertSections sections: IndexSet) {
+        collectionView.insertSections(sections)
+    }
+
+    public func sectionProviderMapper(_ sectionProviderMapper: SectionProviderMapper, didInsertElementsAt indexPaths: [IndexPath]) {
+        collectionView.insertItems(at: indexPaths)
+    }
+
+    // MARK: - UICollectionViewDataSource
+
+    public func numberOfSections(in collectionView: UICollectionView) -> Int {
+        return mapper.numberOfSections
+    }
+
+    public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
+        return collectionUIConfigurationProvider(for: section)?.numberOfElements ?? 0
+    }
+
+    public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
+        guard let configuration = collectionUIConfigurationProvider(for: indexPath.section) else {
+            fatalError("No UI configuration available for section \(indexPath.section)")
+        }
+
+        let type = Swift.type(of: configuration.prototype)
+        switch configuration.dequeueMethod {
+        case .nib:
+            let nib = UINib(nibName: String(describing: type), bundle: Bundle(for: type))
+            collectionView.register(nib, forCellWithReuseIdentifier: configuration.reuseIdentifier)
+        case .class:
+            collectionView.register(type, forCellWithReuseIdentifier: configuration.reuseIdentifier)
+        }
+
+        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: configuration.reuseIdentifier, for: indexPath)
+        configuration.configure(cell: cell, at: indexPath.row)
+        return cell
+    }
+
+    private func collectionUIConfigurationProvider(for section: Int) -> CollectionUIConfiguration? {
+        return (mapper.globalProvider.sections[section] as? CollectionUIConfigurationProvider)?.collectionUIConfiguration
+    }
+
+}

Composed/Core/Sections/ComposedSectionProvider.swift

@@ -41,6 +41,8 @@ public final class ComposedSectionProvider: AggregateSectionProvider, SectionPro
         })
     }
 
+    public init() { }
+
     public func numberOfElements(in section: Int) -> Int {
         return sections[section].numberOfElements
     }
@@ -72,7 +74,7 @@ public final class ComposedSectionProvider: AggregateSectionProvider, SectionPro
         return -1
     }
 
-    func append(_ child: SectionProvider) {
+    public func append(_ child: SectionProvider) {
         child.updateDelegate = self
 
         let firstIndex = sections.count
@@ -82,7 +84,7 @@ public final class ComposedSectionProvider: AggregateSectionProvider, SectionPro
         updateDelegate?.provider(self, didInsertSections: child.sections, at: IndexSet(integersIn: firstIndex..<endIndex))
     }
 
-    func append(_ child: Section) {
+    public func append(_ child: Section) {
         let index = children.count
         children.append(.section(child))
         updateDelegate?.provider(self, didInsertSections: [child], at: IndexSet(integer: index))

Composed/Core/Sections/UI/CollectionUIConfiguration.swift

@@ -0,0 +1,24 @@
+import UIKit
+
+public protocol CollectionUIConfiguration {
+    var headerConfiguration: CollectionUIViewProvider? { get }
+    var footerConfiguration: CollectionUIViewProvider? { get }
+    var backgroundViewClass: UICollectionReusableView.Type? { get }
+    var numberOfElements: Int { get }
+    var reuseIdentifier: String { get }
+    var prototype: UICollectionReusableView { get }
+    var dequeueMethod: DequeueMethod { get }
+
+    func configure(cell: UICollectionViewCell, at index: Int)
+}
+
+public enum DequeueMethod {
+    /// Load from a nib
+    case nib
+    /// Load from a class
+    case `class`
+}
+
+public protocol CollectionUIConfigurationProvider {
+    var collectionUIConfiguration: CollectionUIConfiguration { get }
+}

Composed/Core/Sections/UI/SectionCollectionUIConfiguration.swift

@@ -0,0 +1,58 @@
+import UIKit
+
+open class SectionCollectionUIConfiguration: CollectionUIConfiguration {
+
+    public let headerConfiguration: CollectionUIViewProvider?
+
+    public let footerConfiguration: CollectionUIViewProvider?
+
+    public let backgroundViewClass: UICollectionReusableView.Type?
+
+    open var numberOfElements: Int {
+        return section?.numberOfElements ?? 0
+    }
+
+    public private(set) lazy var reuseIdentifier: String = {
+        return prototype.reuseIdentifier ?? type(of: prototype).reuseIdentifier
+    }()
+
+    public let dequeueMethod: DequeueMethod
+
+    private let prototypeProvider: () -> UICollectionReusableView
+    private var _prototypeView: UICollectionReusableView?
+
+    public var prototype: UICollectionReusableView {
+        if let view = _prototypeView { return view }
+        let view = prototypeProvider()
+        _prototypeView = view
+        return view
+    }
+
+    private weak var section: Section?
+    private let configureCell: (UICollectionViewCell, Int) -> Void
+
+    public init<Cell: UICollectionViewCell, Section: Composed.Section>(section: Section, prototype: @escaping @autoclosure () -> Cell, cellDequeueMethod: DequeueMethod, cellReuseIdentifier: String? = nil, cellConfigurator: @escaping (Cell, Int, Section) -> Void, headerConfiguration: CollectionUIViewProvider? = nil, footerConfiguration: CollectionUIViewProvider? = nil, backgroundViewClass: UICollectionReusableView.Type? = nil) {
+        self.section = section
+        self.prototypeProvider = prototype
+        self.dequeueMethod = cellDequeueMethod
+        self.configureCell = { [weak section] c, index in
+            guard let cell = c as? Cell else {
+                assertionFailure("Got an unknown cell. Expecting cell of type \(Cell.self), got \(c)")
+                return
+            }
+            guard let section = section else {
+                assertionFailure("Asked to configure cell after section has been deallocated")
+                return
+            }
+            cellConfigurator(cell, index, section)
+        }
+        self.headerConfiguration = headerConfiguration
+        self.footerConfiguration = footerConfiguration
+        self.backgroundViewClass = backgroundViewClass
+    }
+
+    public func configure(cell: UICollectionViewCell, at index: Int) {
+        configureCell(cell, index)
+    }
+
+}