A9Cache: support for limiting the max number of items cached for a given slot id.

1Weather/Ads/AmazonA9/A9Cache.swift

@@ -157,14 +157,19 @@ class A9Cache {
             log.error("Couldn't start a9 preload for slotId \(slotId) adType \(adType): failed to determine adSize!")
             fatalError()
         }
-        
+        let maxCount = configManager.adConfig.a9MaxCachedPerPlacement
+        var uncappedCount = count
         if let cacheItem = cacheItems[slotId] {
-            cacheItem.countToCache += count
+            uncappedCount = cacheItem.countToCache + count
+            cacheItem.countToCache = min(uncappedCount, maxCount)
         }
         else {
-            let newCacheItem = A9CacheItem(slotId: slotId, adSize: adSize, count: count, cache: self)
+            let newCacheItem = A9CacheItem(slotId: slotId, adSize: adSize, count: min(uncappedCount, maxCount), cache: self)
             cacheItems[slotId] = newCacheItem
         }
+        if uncappedCount > maxCount {
+            log.debug("Limit cached count for slotId \(slotId) to \(maxCount)")
+        }
     }
     
     private func preloadAllIfNeeded() {

1Weather/Ads/Configuration/AdConfig.swift

@@ -9,8 +9,11 @@
 import UIKit
 
 struct AdConfig: Codable {
+    private static let defaultA9MaxCachedPerPlacement: UInt = 2
+    
     var adsEnabled: Bool
     var a9RefreshRate: Int
+    var a9MaxCachedPerPlacement: UInt
     
     var placements: [AdPlacementName: AdPlacement]?
     var nativePlacements: [AdPlacementName: NativeAdPlacement]?
@@ -33,12 +36,14 @@ struct AdConfig: Codable {
         
         static let adsEnabled = CodingKeys(stringValue: "ads_enabled")
         static let a9RefreshRate = CodingKeys(stringValue: "a9_refresh_rate")
+        static let a9MaxCachedPerPlacement = CodingKeys(stringValue: "a9_max_cached_per_placement")
         static let placements = CodingKeys(stringValue: "placements")
     }
     
     init() {
         adsEnabled = true
         a9RefreshRate = 0
+        a9MaxCachedPerPlacement = AdConfig.defaultA9MaxCachedPerPlacement
     }
     
     init(from decoder: Decoder) throws {
@@ -46,7 +51,9 @@ struct AdConfig: Codable {
         
         adsEnabled = try container.decode(Bool.self, forKey: .adsEnabled)
         a9RefreshRate = try container.decode(Int.self, forKey: .a9RefreshRate)
-        
+        a9MaxCachedPerPlacement = try container.decodeIfPresent(UInt.self, forKey: .a9MaxCachedPerPlacement) ??
+            AdConfig.defaultA9MaxCachedPerPlacement
+
         if container.contains(.placements) {
             let allPlacementsContainer = try container.nestedContainer(keyedBy: CodingKeys.self, forKey: .placements)
             var placements = [AdPlacementName: AdPlacement](minimumCapacity: allPlacementsContainer.allKeys.count)