Temp

submodules/TelegramUI/Sources/SharedVideoContextManager.swift

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+import Foundation
+import UIKit
+import AsyncDisplayKit
+import SwiftSignalKit
+
+class SharedVideoContext {
+    func dispose() {
+    }
+}
+
+private final class SharedVideoContextSubscriber {
+    let id: Int32
+    let priority: Int32
+    let update: (SharedVideoContext?) -> Void
+    var active: Bool = false
+    
+    init(id: Int32, priority: Int32, update: @escaping (SharedVideoContext?) -> Void) {
+        self.id = id
+        self.priority = priority
+        self.update = update
+    }
+}
+
+private final class SharedVideoContextHolder {
+    private var nextId: Int32 = 0
+    private var subscribers: [SharedVideoContextSubscriber] = []
+    let context: SharedVideoContext
+    
+    init(context: SharedVideoContext) {
+        self.context = context
+    }
+    
+    var isEmpty: Bool {
+        return self.subscribers.isEmpty
+    }
+    
+    func addSubscriber(priority: Int32, update: @escaping (SharedVideoContext?) -> Void) -> Int32 {
+        let id = self.nextId
+        self.nextId += 1
+        
+        self.subscribers.append(SharedVideoContextSubscriber(id: id, priority: priority, update: update))
+        self.subscribers.sort(by: { lhs, rhs in
+            if lhs.priority != rhs.priority {
+                return lhs.priority < rhs.priority
+            }
+            return lhs.id < rhs.id
+        })
+        
+        return id
+    }
+    
+    func removeSubscriberAndUpdate(id: Int32) {
+        for i in 0 ..< self.subscribers.count {
+            if self.subscribers[i].id == id {
+                let subscriber = self.subscribers[i]
+                self.subscribers.remove(at: i)
+                if subscriber.active {
+                    subscriber.update(nil)
+                    self.update()
+                }
+                break
+            }
+        }
+    }
+    
+    func update() {
+        for i in (0 ..< self.subscribers.count) {
+            if i == self.subscribers.count - 1 {
+                if !self.subscribers[i].active {
+                    self.subscribers[i].active = true
+                    self.subscribers[i].update(self.context)
+                }
+            } else {
+                if self.subscribers[i].active {
+                    self.subscribers[i].active = false
+                    self.subscribers[i].update(nil)
+                }
+            }
+        }
+    }
+}
+
+final class SharedVideoContextManager {
+    private var holders: [AnyHashable: SharedVideoContextHolder] = [:]
+    
+    func attachSharedVideoContext(id: AnyHashable, priority: Int32, create: () -> SharedVideoContext, update: @escaping (SharedVideoContext?) -> Void) -> Int32 {
+        assert(Queue.mainQueue().isCurrent())
+        
+        let holder: SharedVideoContextHolder
+        if let current = self.holders[id] {
+            holder = current
+        } else {
+            holder = SharedVideoContextHolder(context: create())
+            self.holders[id] = holder
+        }
+        
+        let id = holder.addSubscriber(priority: priority, update: update)
+        holder.update()
+        return id
+    }
+    
+    func detachSharedVideoContext(id: AnyHashable, index: Int32) {
+        assert(Queue.mainQueue().isCurrent())
+        
+        if let holder = self.holders[id] {
+            holder.removeSubscriberAndUpdate(id: index)
+            if holder.isEmpty {
+                holder.context.dispose()
+                self.holders.removeValue(forKey: id)
+            }
+        }
+    }
+    
+    func withSharedVideoContext(id: AnyHashable, _ f: (SharedVideoContext?) -> Void) {
+        if let holder = self.holders[id] {
+            f(holder.context)
+        } else {
+            f(nil)
+        }
+    }
+}