GH-339 React to scroll events on both sides

VimR/MarkdownRenderer.swift

@@ -102,6 +102,7 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
   }
 
   fileprivate let flow: EmbeddableComponent
+  fileprivate let scrollFlow: EmbeddableComponent
 
   fileprivate let scheduler = ConcurrentDispatchQueueScheduler(qos: .userInitiated)
   fileprivate let baseUrl = Bundle.main.resourceURL!.appendingPathComponent("markdown")
@@ -131,6 +132,10 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
     return self.flow.sink
   }
 
+  var scrollSink: Observable<Any> {
+    return self.scrollFlow.sink
+  }
+
   let toolbar: NSView? = NSView(forAutoLayout: ())
   let menuItems: [NSMenuItem]?
 
@@ -151,6 +156,7 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
     self.template = template
 
     self.flow = EmbeddableComponent(source: source)
+    self.scrollFlow = EmbeddableComponent(source: scrollSource)
 
     let configuration = WKWebViewConfiguration()
     configuration.userContentController = self.userContentController
@@ -185,8 +191,6 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
 
     super.init()
 
-    self.flow.set(subscription: self.subscription)
-
     self.initCustomUiElements()
 
     refreshMenuItem.target = self
@@ -202,13 +206,8 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
     refreshOnWriteMenuItem.target = self
     refreshOnWriteMenuItem.action = #selector(MarkdownRenderer.refreshOnWriteAction)
 
-    scrollSource
+    self.flow.set(subscription: self.subscription)
-      .throttle(1, latest: true, scheduler: self.scheduler)
+    self.scrollFlow.set(subscription: self.scrollSubscription)
-      .filter { $0 is MainWindowComponent.ScrollAction }
-      .subscribe(onNext: { action in
-        NSLog("neovim scrolled to  \(self.neoVimInfoProvider?.currentLine()) x \(self.neoVimInfoProvider?.currentColumn())")
-      })
-      .addDisposableTo(self.flow.disposeBag)
 
     self.addReactions()
     self.userContentController.add(webviewMessageHandler, name: "com_vimr_preview_markdown")
@@ -218,6 +217,15 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
     return extensions.contains(fileExtension)
   }
 
+  fileprivate func scrollSubscription(source: Observable<Any>) -> Disposable {
+    return source
+      .throttle(1, latest: true, scheduler: self.scheduler)
+      .filter { $0 is MainWindowComponent.ScrollAction }
+      .subscribe(onNext: { [unowned self] action in
+        NSLog("neovim scrolled to  \(self.neoVimInfoProvider?.currentLine()) x \(self.neoVimInfoProvider?.currentColumn())")
+      })
+  }
+
   fileprivate func subscription(source: Observable<Any>) -> Disposable {
     return source
       .observeOn(self.scheduler)
@@ -281,7 +289,9 @@ class MarkdownRenderer: NSObject, Flow, PreviewRenderer {
         switch action {
         case let .scroll(lineBegin, columnBegin, _, _):
           self?.currentPreviewPosition = Position(row: lineBegin, column: columnBegin)
-          self?.flow.publish(event: PreviewRendererAction.scroll(to: Position(row: lineBegin, column: columnBegin)))
+          self?.scrollFlow.publish(
+            event: PreviewRendererAction.scroll(to: Position(row: lineBegin, column: columnBegin))
+          )
         }
       })
       .addDisposableTo(self.flow.disposeBag)

VimR/PreviewComponent.swift

@@ -73,6 +73,7 @@ class PreviewComponent: NSView, ViewComponent, ToolDataHolder {
     }
   }
 
+  fileprivate let scheduler = ConcurrentDispatchQueueScheduler(qos: .userInitiated)
   fileprivate let flow: EmbeddableComponent
 
   fileprivate var currentUrl: URL?
@@ -136,7 +137,7 @@ class PreviewComponent: NSView, ViewComponent, ToolDataHolder {
   var view: NSView {
     return self
   }
-  
+
   init(source: Observable<Any>, scrollSource: Observable<Any>, neoVimInfoProvider: NeoVimInfoProvider, initialData: PrefData) {
     self.neoVimInfoProvider = neoVimInfoProvider
     self.flow = EmbeddableComponent(source: source)
@@ -224,6 +225,25 @@ class PreviewComponent: NSView, ViewComponent, ToolDataHolder {
   }
 
   fileprivate func addReactions() {
+    self.markdownRenderer.scrollSink
+      .throttle(1, latest: true, scheduler: self.scheduler)
+      .filter { $0 is PreviewRendererAction }
+      .map { $0 as! PreviewRendererAction }
+      .subscribe(onNext: { action in
+        guard self.isOpen else {
+          return
+        }
+
+        switch action {
+        case let .scroll(to:position):
+          self.flow.publish(event: PreviewComponent.Action.scroll(to: position))
+
+        default:
+          return
+        }
+      })
+      .addDisposableTo(self.flow.disposeBag)
+
     self.markdownRenderer.sink
       .filter { $0 is PreviewRendererAction }
       .map { $0 as! PreviewRendererAction }
@@ -241,12 +261,12 @@ class PreviewComponent: NSView, ViewComponent, ToolDataHolder {
         case let .view(_, view):
           self.currentView = view
 
-        case let .scroll(to: position):
-          self.flow.publish(event: PreviewComponent.Action.scroll(to: position))
-
         case .error:
           self.webview.loadHTMLString(self.previewService.errorHtml(), baseURL: self.baseUrl)
 
+        default:
+          return
+
         }
       })
       .addDisposableTo(self.flow.disposeBag)

VimR/PreviewRenderer.swift

@@ -4,6 +4,7 @@
  */
 
 import Cocoa
+import RxSwift
 
 protocol PreviewRenderer: class {
 
@@ -12,6 +13,7 @@ protocol PreviewRenderer: class {
 
   var identifier: String { get }
   var prefData: StandardPrefData? { get }
+  var scrollSink: Observable<Any> { get }
 
   var toolbar: NSView? { get }
   var menuItems: [NSMenuItem]? { get }