Additional conveniences for offset pagination

apollographql · Feb 14, 2024 · fe2de1a · fe2de1a
1 parent c2de5b7
commit fe2de1a
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Showing 5 changed files with 306 additions and 26 deletions.
diff --git a/apollo-ios-pagination/Sources/ApolloPagination/GraphQLQueryPager+Convenience.swift b/apollo-ios-pagination/Sources/ApolloPagination/GraphQLQueryPager+Convenience.swift
@@ -11,8 +11,8 @@ public extension GraphQLQueryPager {
   static func makeForwardOffsetQueryPager<InitialQuery: GraphQLQuery>(
     client: ApolloClientProtocol,
     watcherDispatchQueue: DispatchQueue = .main,
-    queryProvider: @escaping (OffsetPagination?) -> InitialQuery,
-    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination
+    queryProvider: @escaping (OffsetPagination.Forward?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Forward
   ) -> GraphQLQueryPager where Model == PaginationOutput<InitialQuery, InitialQuery> {
     GraphQLQueryPager(pager: GraphQLQueryPagerCoordinator(
       client: client,
@@ -26,11 +26,33 @@ public extension GraphQLQueryPager {
     ))
   }
 
+  static func makeForwardOffsetQueryPager<InitialQuery: GraphQLQuery>(
+    client: ApolloClientProtocol,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Forward?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Forward,
+    transform: @escaping ([InitialQuery.Data], InitialQuery.Data, [InitialQuery.Data]) throws -> Model
+  ) -> GraphQLQueryPager {
+    GraphQLQueryPager(
+      pager: GraphQLQueryPagerCoordinator(
+        client: client,
+        initialQuery: queryProvider(nil),
+        watcherDispatchQueue: watcherDispatchQueue,
+        extractPageInfo: pageExtraction(transform: extractPageInfo),
+        pageResolver: { page, direction in
+          guard direction == .next else { return nil }
+          return queryProvider(page)
+        }
+      ),
+      transform: transform
+    )
+  }
+
   static func makeForwardOffsetQueryPager<InitialQuery: GraphQLQuery, T>(
     client: ApolloClientProtocol,
     watcherDispatchQueue: DispatchQueue = .main,
-    queryProvider: @escaping (OffsetPagination?) -> InitialQuery,
-    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination,
+    queryProvider: @escaping (OffsetPagination.Forward?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Forward,
     transform: @escaping (InitialQuery.Data) throws -> Model
   ) -> GraphQLQueryPager where Model: RangeReplaceableCollection, T == Model.Element {
     GraphQLQueryPager(
@@ -52,8 +74,8 @@ public extension GraphQLQueryPager {
   static func makeReverseOffsetQueryPager<InitialQuery: GraphQLQuery>(
     client: ApolloClientProtocol,
     watcherDispatchQueue: DispatchQueue = .main,
-    queryProvider: @escaping (OffsetPagination?) -> InitialQuery,
-    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination
+    queryProvider: @escaping (OffsetPagination.Reverse?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Reverse
   ) -> GraphQLQueryPager where Model == PaginationOutput<InitialQuery, InitialQuery> {
     GraphQLQueryPager(pager: GraphQLQueryPagerCoordinator(
       client: client,
@@ -67,11 +89,33 @@ public extension GraphQLQueryPager {
     ))
   }
 
+  static func makeReverseOffsetQueryPager<InitialQuery: GraphQLQuery>(
+    client: ApolloClientProtocol,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Reverse?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Reverse,
+    transform: @escaping ([InitialQuery.Data], InitialQuery.Data, [InitialQuery.Data]) throws -> Model
+  ) -> GraphQLQueryPager {
+    GraphQLQueryPager(
+      pager: GraphQLQueryPagerCoordinator(
+        client: client,
+        initialQuery: queryProvider(nil),
+        watcherDispatchQueue: watcherDispatchQueue,
+        extractPageInfo: pageExtraction(transform: extractPageInfo),
+        pageResolver: { page, direction in
+          guard direction == .previous else { return nil }
+          return queryProvider(page)
+        }
+      ),
+      transform: transform
+    )
+  }
+
   static func makeReverseOffsetQueryPager<InitialQuery: GraphQLQuery, T>(
     client: ApolloClientProtocol,
     watcherDispatchQueue: DispatchQueue = .main,
-    queryProvider: @escaping (OffsetPagination?) -> InitialQuery,
-    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination,
+    queryProvider: @escaping (OffsetPagination.Reverse?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Reverse,
     transform: @escaping (InitialQuery.Data) throws -> Model
   ) -> GraphQLQueryPager where Model: RangeReplaceableCollection, T == Model.Element {
     GraphQLQueryPager(
@@ -90,6 +134,87 @@ public extension GraphQLQueryPager {
     )
   }
 
+  static func makeBidirectionalOffsetQueryPager<InitialQuery: GraphQLQuery>(
+    client: ApolloClientProtocol,
+    start: OffsetPagination.Bidirectional?,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    previousQueryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Bidirectional
+  ) -> GraphQLQueryPager where Model == PaginationOutput<InitialQuery, InitialQuery> {
+    GraphQLQueryPager(pager: GraphQLQueryPagerCoordinator(
+      client: client,
+      initialQuery: queryProvider(start),
+      watcherDispatchQueue: watcherDispatchQueue,
+      extractPageInfo: pageExtraction(transform: extractPageInfo),
+      pageResolver: { page, direction in
+        switch direction {
+        case .next:
+          return queryProvider(page)
+        case .previous:
+          return previousQueryProvider(page)
+        }
+      }
+    ))
+  }
+
+  static func makeBidirectionalOffsetQueryPager<InitialQuery: GraphQLQuery>(
+    client: ApolloClientProtocol,
+    start: OffsetPagination.Bidirectional?,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    previousQueryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Bidirectional,
+    transform: @escaping ([InitialQuery.Data], InitialQuery.Data, [InitialQuery.Data]) throws -> Model
+  ) -> GraphQLQueryPager {
+    GraphQLQueryPager(
+      pager: GraphQLQueryPagerCoordinator(
+        client: client,
+        initialQuery: queryProvider(start),
+        watcherDispatchQueue: watcherDispatchQueue,
+        extractPageInfo: pageExtraction(transform: extractPageInfo),
+        pageResolver: { page, direction in
+          switch direction {
+          case .next:
+            return queryProvider(page)
+          case .previous:
+            return previousQueryProvider(page)
+          }
+        }
+      ),
+      transform: transform
+    )
+  }
+
+  static func makeBidirectionalOffsetQueryPager<InitialQuery: GraphQLQuery, T>(
+    client: ApolloClientProtocol,
+    start: OffsetPagination.Bidirectional?,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    previousQueryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Bidirectional,
+    transform: @escaping (InitialQuery.Data) throws -> Model
+  ) -> GraphQLQueryPager where Model: RangeReplaceableCollection, T == Model.Element {
+    GraphQLQueryPager(
+      pager: GraphQLQueryPagerCoordinator(
+        client: client,
+        initialQuery: queryProvider(start),
+        watcherDispatchQueue: watcherDispatchQueue,
+        extractPageInfo: pageExtraction(transform: extractPageInfo),
+        pageResolver: { page, direction in
+          switch direction {
+          case .next:
+            return queryProvider(page)
+          case .previous:
+            return previousQueryProvider(page)
+          }
+        }
+      ),
+      initialTransform: transform,
+      pageTransform: transform
+    )
+  }
+
   // MARK: CursorBasedPagination.Forward Initializers
 
   /// This convenience function creates an `GraphQLQueryPager` that paginates forward with only one query and has an output type of `Result<(PaginationOutput<InitialQuery, InitialQuery>, UpdateSource), Error>`.
@@ -522,8 +647,8 @@ public extension AsyncGraphQLQueryPager {
   static func makeForwardOffsetQueryPager<InitialQuery: GraphQLQuery>(
     client: ApolloClientProtocol,
     watcherDispatchQueue: DispatchQueue = .main,
-    queryProvider: @escaping (OffsetPagination?) -> InitialQuery,
-    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination
+    queryProvider: @escaping (OffsetPagination.Forward?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Forward
   ) async -> AsyncGraphQLQueryPager where Model == PaginationOutput<InitialQuery, InitialQuery> {
     await AsyncGraphQLQueryPager(pager: AsyncGraphQLQueryPagerCoordinator(
       client: client,
@@ -537,11 +662,33 @@ public extension AsyncGraphQLQueryPager {
     ))
   }
 
+  static func makeForwardOffsetQueryPager<InitialQuery: GraphQLQuery>(
+    client: ApolloClientProtocol,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Forward?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Forward,
+    transform: @escaping ([InitialQuery.Data], InitialQuery.Data, [InitialQuery.Data]) throws -> Model
+  ) async -> AsyncGraphQLQueryPager {
+    await AsyncGraphQLQueryPager(
+      pager: AsyncGraphQLQueryPagerCoordinator(
+        client: client,
+        initialQuery: queryProvider(nil),
+        watcherDispatchQueue: watcherDispatchQueue,
+        extractPageInfo: pageExtraction(transform: extractPageInfo),
+        pageResolver: { page, direction in
+          guard direction == .next else { return nil }
+          return queryProvider(page)
+        }
+      ),
+      transform: transform
+    )
+  }
+
   static func makeForwardOffsetQueryPager<InitialQuery: GraphQLQuery, T>(
     client: ApolloClientProtocol,
     watcherDispatchQueue: DispatchQueue = .main,
-    queryProvider: @escaping (OffsetPagination?) -> InitialQuery,
-    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination,
+    queryProvider: @escaping (OffsetPagination.Forward?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Forward,
     transform: @escaping (InitialQuery.Data) throws -> Model
   ) async -> AsyncGraphQLQueryPager where Model: RangeReplaceableCollection, T == Model.Element {
     await AsyncGraphQLQueryPager(
@@ -563,8 +710,8 @@ public extension AsyncGraphQLQueryPager {
   static func makeReverseOffsetQueryPager<InitialQuery: GraphQLQuery>(
     client: ApolloClientProtocol,
     watcherDispatchQueue: DispatchQueue = .main,
-    queryProvider: @escaping (OffsetPagination?) -> InitialQuery,
-    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination
+    queryProvider: @escaping (OffsetPagination.Reverse?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Reverse
   ) async -> AsyncGraphQLQueryPager where Model == PaginationOutput<InitialQuery, InitialQuery> {
     await AsyncGraphQLQueryPager(pager: AsyncGraphQLQueryPagerCoordinator(
       client: client,
@@ -578,11 +725,33 @@ public extension AsyncGraphQLQueryPager {
     ))
   }
 
+  static func makeReverseOffsetQueryPager<InitialQuery: GraphQLQuery>(
+    client: ApolloClientProtocol,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Reverse?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Reverse,
+    transform: @escaping ([InitialQuery.Data], InitialQuery.Data, [InitialQuery.Data]) throws -> Model
+  ) async -> AsyncGraphQLQueryPager {
+    await AsyncGraphQLQueryPager(
+      pager: AsyncGraphQLQueryPagerCoordinator(
+        client: client,
+        initialQuery: queryProvider(nil),
+        watcherDispatchQueue: watcherDispatchQueue,
+        extractPageInfo: pageExtraction(transform: extractPageInfo),
+        pageResolver: { page, direction in
+          guard direction == .previous else { return nil }
+          return queryProvider(page)
+        }
+      ),
+      transform: transform
+    )
+  }
+
   static func makeReverseOffsetQueryPager<InitialQuery: GraphQLQuery, T>(
     client: ApolloClientProtocol,
     watcherDispatchQueue: DispatchQueue = .main,
-    queryProvider: @escaping (OffsetPagination?) -> InitialQuery,
-    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination,
+    queryProvider: @escaping (OffsetPagination.Reverse?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Reverse,
     transform: @escaping (InitialQuery.Data) throws -> Model
   ) async -> AsyncGraphQLQueryPager where Model: RangeReplaceableCollection, T == Model.Element {
     await AsyncGraphQLQueryPager(
@@ -601,6 +770,87 @@ public extension AsyncGraphQLQueryPager {
     )
   }
 
+  static func makeBidirectionalOffsetQueryPager<InitialQuery: GraphQLQuery>(
+    client: ApolloClientProtocol,
+    start: OffsetPagination.Bidirectional?,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    previousQueryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Bidirectional
+  ) async -> AsyncGraphQLQueryPager where Model == PaginationOutput<InitialQuery, InitialQuery> {
+    await AsyncGraphQLQueryPager(pager: AsyncGraphQLQueryPagerCoordinator(
+      client: client,
+      initialQuery: queryProvider(start),
+      watcherDispatchQueue: watcherDispatchQueue,
+      extractPageInfo: pageExtraction(transform: extractPageInfo),
+      pageResolver: { page, direction in
+        switch direction {
+        case .next:
+          return queryProvider(page)
+        case .previous:
+          return previousQueryProvider(page)
+        }
+      }
+    ))
+  }
+
+  static func makeBidirectionalOffsetQueryPager<InitialQuery: GraphQLQuery>(
+    client: ApolloClientProtocol,
+    start: OffsetPagination.Bidirectional?,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    previousQueryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Bidirectional,
+    transform: @escaping ([InitialQuery.Data], InitialQuery.Data, [InitialQuery.Data]) throws -> Model
+  ) async -> AsyncGraphQLQueryPager {
+    await AsyncGraphQLQueryPager(
+      pager: AsyncGraphQLQueryPagerCoordinator(
+        client: client,
+        initialQuery: queryProvider(start),
+        watcherDispatchQueue: watcherDispatchQueue,
+        extractPageInfo: pageExtraction(transform: extractPageInfo),
+        pageResolver: { page, direction in
+          switch direction {
+          case .next:
+            return queryProvider(page)
+          case .previous:
+            return previousQueryProvider(page)
+          }
+        }
+      ),
+      transform: transform
+    )
+  }
+
+  static func makeBidirectionalOffsetQueryPager<InitialQuery: GraphQLQuery, T>(
+    client: ApolloClientProtocol,
+    start: OffsetPagination.Bidirectional?,
+    watcherDispatchQueue: DispatchQueue = .main,
+    queryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    previousQueryProvider: @escaping (OffsetPagination.Bidirectional?) -> InitialQuery,
+    extractPageInfo: @escaping (InitialQuery.Data) -> OffsetPagination.Bidirectional,
+    transform: @escaping (InitialQuery.Data) throws -> Model
+  ) async -> AsyncGraphQLQueryPager where Model: RangeReplaceableCollection, T == Model.Element {
+    await AsyncGraphQLQueryPager(
+      pager: AsyncGraphQLQueryPagerCoordinator(
+        client: client,
+        initialQuery: queryProvider(start),
+        watcherDispatchQueue: watcherDispatchQueue,
+        extractPageInfo: pageExtraction(transform: extractPageInfo),
+        pageResolver: { page, direction in
+          switch direction {
+          case .next:
+            return queryProvider(page)
+          case .previous:
+            return previousQueryProvider(page)
+          }
+        }
+      ),
+      initialTransform: transform,
+      pageTransform: transform
+    )
+  }
+
   // MARK: CursorBasedPagination.Forward Initializers
 
   /// This convenience function creates an `AsyncGraphQLQueryPager` that paginates forward with only one query and has an output type of `Result<(PaginationOutput<InitialQuery, InitialQuery>, UpdateSource), Error>`.

diff --git a/apollo-ios-pagination/Sources/ApolloPagination/OffsetBasedPagination/Bidirectional.swift b/apollo-ios-pagination/Sources/ApolloPagination/OffsetBasedPagination/Bidirectional.swift
@@ -0,0 +1,13 @@
+extension OffsetPagination {
+  public struct Bidirectional: PaginationInfo, Hashable {
+    public let offset: Int
+    public var canLoadNext: Bool
+    public let canLoadPrevious: Bool
+
+    public init(offset: Int, canLoadNext: Bool, canLoadPrevious: Bool) {
+      self.offset = offset
+      self.canLoadNext = canLoadNext
+      self.canLoadPrevious = canLoadPrevious
+    }
+  }
+}
diff --git a/apollo-ios-pagination/Sources/ApolloPagination/OffsetBasedPagination/ForwardOffset.swift b/apollo-ios-pagination/Sources/ApolloPagination/OffsetBasedPagination/ForwardOffset.swift
@@ -0,0 +1,13 @@
+extension OffsetPagination {
+  public struct Forward: PaginationInfo, Hashable {
+    public let offset: Int
+    public let canLoadNext: Bool
+    public var canLoadPrevious: Bool { false }
+
+    public init(offset: Int, canLoadNext: Bool) {
+      self.offset = offset
+      self.canLoadNext = canLoadNext
+    }
+  }
+
+}