Merge branch 'master' of github.com:algolia/instantsearch-core-swift

Sources/Searcher.swift

@@ -207,6 +207,12 @@ import Foundation
     /// All currently ongoing requests.
     private var pendingRequests: [Int: Operation] = [:]
 
+    /// Maximum number of pending requests allowed.
+    /// If many requests are made in a short time, this will keep only the N most recent and cancel the older ones.
+    /// This helps to avoid filling up the request queue when the network is slow.
+    ///
+    @objc public var maxPendingRequests: Int = 3
+
     // MARK: - Initialization, termination
 
     /// Create a new searcher targeting the specified index.
@@ -339,6 +345,12 @@ import Foundation
             Searcher.notificationSeqNoKey: currentSeqNo
         ]
 
+        // Cancel too old requests.
+        let tooOldRequests = pendingRequests.filter({ $0.0 <= currentSeqNo - maxPendingRequests })
+        for (seqNo, _) in tooOldRequests {
+            cancelRequest(seqNo: seqNo)
+        }
+
         // Run request
         // -----------
         var operation: Operation!
@@ -416,6 +428,37 @@ import Foundation
         }
     }
 
+    // MARK: - Search for facet values
+
+    /// Search for values of a given facet.
+    ///
+    /// This is a convenience shortcut for Algolia Search's `Index.searchForFacetValues(...)` method that will
+    /// automatically use the current search `params` as the refining query, also taking into account the
+    /// conjunctive/disjunctive status of the targeted facet (i.e. refinements for the targeted facet will be discarded
+    /// when the facet is disjunctive).
+    ///
+    /// Unlike a regular `search()`:
+    ///
+    /// - The searched text has to be passed as an argument to the method, as it differs in purpose from `params.query`.
+    /// - Result handlers or the delegate are not called; instead, the provided completion handler is called.
+    ///   Notifications are not issued either.
+    ///
+    /// - parameter facetName: Name of the facet to search. It must have been declared in the index's
+    ///       `attributesForFaceting` setting with the `searchable()` modifier.
+    /// - parameter text: Text to search for in the facet's values.
+    /// - parameter completionHandler: Completion handler to be notified of the request's outcome.
+    /// - returns: A cancellable operation.
+    ///
+    @objc @discardableResult
+    public func searchForFacetValues(of facetName: String, matching text: String, completionHandler: @escaping CompletionHandler) -> Operation {
+        let facetSearchParams = SearchParameters(from: self.params)
+        // If the searched facet is disjunctive, clear any refinements that it may have.
+        if facetSearchParams.isDisjunctiveFacet(name: facetName) {
+            facetSearchParams.clearFacetRefinements(name: facetName)
+        }
+        return index.searchForFacetValues(of: facetName, matching: text, query: facetSearchParams, completionHandler: completionHandler)
+    }
+
     // MARK: - Managing requests
 
     /// Indicates whether there are any pending requests.