Merge pull request #189 from hotwired/fix-visitable-snapshots-and-dea…

…ctivation-feedback Snapshot and deactivate Visitable during it's lifecycle feedback
hotwired · Mar 22, 2024 · 3bcea29 · 3bcea29
2 parents 979b1a9 + fc05e38
commit 3bcea29
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Showing 6 changed files with 45 additions and 1 deletion.
diff --git a/Source/Session/Session.swift b/Source/Session/Session.swift
@@ -37,6 +37,7 @@ public class Session: NSObject {
 
     private var currentVisit: Visit?
     private var topmostVisit: Visit?
+    private var previousVisit: Visit?
 
     /// The topmost visitable is the visitable that has most recently completed a visit
     public var topmostVisitable: Visitable? {
@@ -227,6 +228,11 @@ extension Session: VisitDelegate {
 
 extension Session: VisitableDelegate {
     public func visitableViewWillAppear(_ visitable: Visitable) {
+        defer {
+            /// Nilling out the previous visit here prevents `double-snapshotting` for web -> web visits.
+            previousVisit = nil
+        }
+
         guard let topmostVisit = self.topmostVisit, let currentVisit = self.currentVisit else { return }
 
         if isSnapshotCacheStale {
@@ -248,7 +254,10 @@ extension Session: VisitableDelegate {
             // Navigating forward - complete navigation early
             completeNavigationForCurrentVisit()
         } else if visitable !== topmostVisit.visitable {
-            // Navigating backward
+            // Navigating backward from a web view screen to a web view screen.
+            visit(visitable, action: .restore)
+        } else if visitable === previousVisit?.visitable {
+            // Navigating backward from a native to a web view screen.
             visit(visitable, action: .restore)
         }
     }
@@ -266,6 +275,15 @@ extension Session: VisitableDelegate {
         }
     }
 
+    public func visitableViewWillDisappear(_ visitable: Visitable) {
+        previousVisit = topmostVisit
+    }
+
+    public func visitableViewDidDisappear(_ visitable: Visitable) {
+        previousVisit?.cacheSnapshot()
+        deactivateVisitable(visitable)
+    }
+
     public func visitableDidRequestReload(_ visitable: Visitable) {
         guard visitable === topmostVisitable else { return }
         reload()

diff --git a/Source/Visit/Visit.swift b/Source/Visit/Visit.swift
@@ -68,6 +68,10 @@ class Visit: NSObject {
         delegate?.visitDidFinish(self)
     }
 
+    func cacheSnapshot() {
+        bridge.cacheSnapshot()
+    }
+
     func startVisit() {}
     func cancelVisit() {}
     func completeVisit() {}

diff --git a/Source/Visitable/Visitable.swift b/Source/Visitable/Visitable.swift
@@ -4,6 +4,8 @@ import WebKit
 public protocol VisitableDelegate: AnyObject {
     func visitableViewWillAppear(_ visitable: Visitable)
     func visitableViewDidAppear(_ visitable: Visitable)
+    func visitableViewWillDisappear(_ visitable: Visitable)
+    func visitableViewDidDisappear(_ visitable: Visitable)
     func visitableDidRequestReload(_ visitable: Visitable)
     func visitableDidRequestRefresh(_ visitable: Visitable)
 }

diff --git a/Source/Visitable/VisitableViewController.swift b/Source/Visitable/VisitableViewController.swift
@@ -28,6 +28,16 @@ open class VisitableViewController: UIViewController, Visitable {
         visitableDelegate?.visitableViewDidAppear(self)
     }
 
+    open override func viewWillDisappear(_ animated: Bool) {
+        super.viewWillDisappear(animated)
+        visitableDelegate?.visitableViewWillDisappear(self)
+    }
+
+    open override func viewDidDisappear(_ animated: Bool) {
+        super.viewDidDisappear(animated)
+        visitableDelegate?.visitableViewDidDisappear(self)
+    }
+
     // MARK: Visitable
 
     open func visitableDidRender() {

diff --git a/Source/WebView/WebViewBridge.swift b/Source/WebView/WebViewBridge.swift
@@ -76,6 +76,10 @@ final class WebViewBridge {
         callJavaScript(function: "window.turboNative.clearSnapshotCache")
     }
 
+    func cacheSnapshot() {
+        callJavaScript(function: "window.turboNative.cacheSnapshot")
+    }
+
     func cancelVisit(withIdentifier identifier: String) {
         callJavaScript(function: "window.turboNative.cancelVisitWithIdentifier", arguments: [identifier])
     }

diff --git a/Source/WebView/turbo.js b/Source/WebView/turbo.js
@@ -64,6 +64,12 @@
       }
     }
 
+    cacheSnapshot() {
+      if (window.Turbo) {
+        Turbo.session.view.cacheSnapshot()
+      }
+    }
+
     // Current visit
 
     issueRequestForVisitWithIdentifier(identifier) {