Merge commit '7621e2f8dec938cf48181c8b10afc9b01f444e68' into beta

submodules/lottie-ios/Sources/Public/AnimationCache/AnimationCacheProvider.swift

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+//
+//  AnimationCacheProvider.swift
+//  lottie-swift
+//
+//  Created by Brandon Withrow on 2/5/19.
+//
+
+import Foundation
+/// `AnimationCacheProvider` is a protocol that describes an Animation Cache.
+/// Animation Cache is used when loading `Animation` models. Using an Animation Cache
+/// can increase performance when loading an animation multiple times.
+///
+/// Lottie comes with a prebuilt LRU Animation Cache.
+public protocol AnimationCacheProvider {
+
+  func animation(forKey: String) -> Animation?
+
+  func setAnimation(_ animation: Animation, forKey: String)
+
+  func clearCache()
+
+}

submodules/lottie-ios/Sources/Public/AnimationCache/LRUAnimationCache.swift

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+//
+//  LRUAnimationCache.swift
+//  lottie-swift
+//
+//  Created by Brandon Withrow on 2/5/19.
+//
+
+import Foundation
+
+/// An Animation Cache that will store animations up to `cacheSize`.
+///
+/// Once `cacheSize` is reached, the least recently used animation will be ejected.
+/// The default size of the cache is 100.
+public class LRUAnimationCache: AnimationCacheProvider {
+
+  // MARK: Lifecycle
+
+  public init() { }
+
+  // MARK: Public
+
+  /// The global shared Cache.
+  public static let sharedCache = LRUAnimationCache()
+
+  /// The size of the cache.
+  public var cacheSize = 100
+
+  /// Clears the Cache.
+  public func clearCache() {
+    cacheMap.removeAll()
+    lruList.removeAll()
+  }
+
+  public func animation(forKey: String) -> Animation? {
+    guard let animation = cacheMap[forKey] else {
+      return nil
+    }
+    if let index = lruList.firstIndex(of: forKey) {
+      lruList.remove(at: index)
+      lruList.append(forKey)
+    }
+    return animation
+  }
+
+  public func setAnimation(_ animation: Animation, forKey: String) {
+    cacheMap[forKey] = animation
+    lruList.append(forKey)
+    if lruList.count > cacheSize {
+      let removed = lruList.remove(at: 0)
+      if removed != forKey {
+        cacheMap[removed] = nil
+      }
+    }
+  }
+
+  // MARK: Fileprivate
+
+  fileprivate var cacheMap: [String: Animation] = [:]
+  fileprivate var lruList: [String] = []
+
+}