Telegram macOS 复制/保存内容限制机制分析

数据来源：服务端标记

限制信息通过 MTProto 协议同步到客户端，分为两个层面：

1. 消息级标记 CopyProtected

• 定义: MessageFlags.CopyProtected = MessageFlags(rawValue: 512) (bit 512)
  • submodules/Postbox/Sources/Message.swift:495
  • submodules/Postbox/Sources/Message.swift:866 (StoreMessageFlags)
• 解析来源: MTProto 消息 flag 第 26 位
  • submodules/TelegramCore/Sources/ApiUtils/StoreMessage_Telegram.swift:1044-1046,1201-1203

2. 对话级标记 copyProtectionEnabled

• 频道: TelegramChannelFlags.copyProtectionEnabled (bit 8)
  • submodules/TelegramCore/Sources/SyncCore/SyncCore_TelegramChannel.swift:181
  • 从 MTProto 第 27 位解析: submodules/TelegramCore/Sources/ApiUtils/ApiGroupOrChannel.swift:125-126
• 群组: TelegramGroupFlags.copyProtectionEnabled (bit 4)
  • submodules/TelegramCore/Sources/SyncCore/SyncCore_TelegramGroup.swift:122
  • 从 MTProto 第 25 位解析: submodules/TelegramCore/Sources/ApiUtils/ApiGroupOrChannel.swift:56-57

3. 服务端切换 API

• submodules/TelegramCore/Sources/TelegramEngine/Peers/CopyProtection.swift:7-17
• 调用 messages.toggleNoForwards 接口

---

核心判断逻辑

通用判断 Message.isCopyProtected()

submodules/TelegramCore/Sources/Utils/MessageUtils.swift:382-392

func isCopyProtected() -> Bool {
    if self.flags.contains(.CopyProtected) { return true }          // 消息级标记
    if group.flags.contains(.copyProtectionEnabled) { return true } // 群组级标记
    if channel.flags.contains(.copyProtectionEnabled) { return true } // 频道级标记
    return false
}

Peer 级判断 Peer.isCopyProtectionEnabled

submodules/TelegramCore/Sources/Utils/PeerUtils.swift:236-245

var isCopyProtectionEnabled: Bool {
    switch self {
    case let group as TelegramGroup:  return group.flags.contains(.copyProtectionEnabled)
    case let channel as TelegramChannel: return channel.flags.contains(.copyProtectionEnabled)
    default: return false
    }
}

macOS 特有判断 Peer.isCopyProtected（对群主/管理员豁免）

Telegram-Mac/CoreExtension.swift:3810-3818

var isCopyProtected: Bool {
    if let peer = self as? TelegramGroup {
        return peer.flags.contains(.copyProtectionEnabled) && !peer.groupAccess.isCreator
    } else if let peer = self as? TelegramChannel {
        return peer.flags.contains(.copyProtectionEnabled) && !(peer.adminRights != nil || peer.groupAccess.isCreator)
    } else {
        return false
    }
}

---

macOS 层执行点

功能	文件	位置	行为
Cmd+C 复制文本	ChatSelectText.swift	L110-115	拦截复制、弹 alert
右键菜单-复制文本	ChatMessageMenuItems.swift	L690	不添加菜单项
右键菜单-复制链接	ChatMessageMenuItems.swift	L701	不添加菜单项
转发到其他聊天	ChatInputAccessory.swift	L297, L328	不添加菜单项
转发能力	ChatRowItem.swift	L1076-1078	canForward 返回 false
Gallery 保存按钮	GalleryModernControls.swift	L190-220	fastSaveControl.isHidden = true
Gallery 右键-另存为	GalleryViewer.swift	L1362-1369	不添加菜单项
Gallery 分享	GalleryViewer.swift	L377-384	canShare 返回 false
MGalleryItem 分享	MGalleryItem.swift	L156	canShare 返回 false
MGalleryItem 保存	MGalleryItem.swift	L326	canSave 返回 false
Gallery 文本识别	GalleryRecognition.swift	L27	跳过 OCR 识别
列表缩略图防截屏	ChatListRowView.swift	L702	preventsCapture = true
管理员开关 UI	ChannelVisibilityController.swift	L719-730	Restrict Copying 开关

---

iOS 层关键执行点（供参考）

功能	文件	位置	行为
文本选择复制	ChatMessageTextBubbleContentNode.swift	L1408-1409	textSelectionNode.enableCopy = false
上下文菜单复制	ChatInterfaceStateContextMenus.swift	L1259-1263	Copy 菜单项不添加
上下文菜单保存到文件	ChatInterfaceStateContextMenus.swift	L1369	不添加菜单项
选中面板-转发/分享	ChatMessageSelectionInputPanelNode.swift	L218-233	弹 copyProtectionTip
另一聊天回复	ChatMessageActionOptions.swift	L424-425	canReplyInAnotherChat = false
Gallery 分享/编辑	ChatItemGalleryFooterContentNode.swift	L943-946	canShare=false, canEdit=false
Gallery 防截屏	ChatImageGalleryItem.swift	L456	setLayerDisableScreenshots
Sticker 分享	ChatMessageStickerItemNode.swift	L566	needsShareButton = false
动画 Sticker 分享	ChatMessageAnimatedStickerItemNode.swift	L945	needsShareButton = false
视频消息分享	ChatMessageInstantVideoItemNode.swift	L384	needsShareButton = false
Bubble 分享	ChatMessageBubbleItemNode.swift	L1783	needsShareButton = false
Video captureProtect	NativeVideoContent.swift	L431-432	captureProtected = true
PeerInfo 防截屏	PeerInfoScreen.swift	L5378-5382	setLayerDisableScreenshots
Story 防截屏	StoryItemImageView.swift	L48-56	UITextField.secureTextEntry 方式
防截屏底层实现	UIKitRuntimeUtils/UIKitUtils.m	L247-269	setLayerDisableScreenshots()

---

架构流程图

服务端 (MTProto)
  │
  ▼
Parsing Layer
  ├── StoreMessage_Telegram.swift         → MessageFlags.CopyProtected (bit 512)
  └── ApiGroupOrChannel.swift             → TelegramChannelFlags / TelegramGroupFlags .copyProtectionEnabled
  │
  ▼
Data Model Layer
  ├── Message.swift                       → flags.contains(.CopyProtected)
  ├── SyncCore_TelegramChannel.swift      → channel.flags.contains(.copyProtectionEnabled)
  └── SyncCore_TelegramGroup.swift        → group.flags.contains(.copyProtectionEnabled)
  │
  ▼
Business Logic Layer
  ├── MessageUtils.swift (isCopyProtected)  → 三者 OR 判断
  ├── PeerUtils.swift (isCopyProtectionEnabled) → peer 级判断
  └── CoreExtension.swift (macOS Peer.isCopyProtected) → 对管理员豁免
  │
  ▼
UI Enforcement Layer
  ├── ChatSelectText.swift                → Cmd+C 拦截
  ├── ChatMessageMenuItems.swift          → 右键菜单项控制
  ├── GalleryModernControls.swift         → 保存按钮隐藏
  ├── GalleryViewer.swift                 → 分享/另存为控制
  ├── ChatInputAccessory.swift            → 转发菜单控制
  ├── ChatRowItem.swift                   → 转发能力控制
  ├── ChatListRowView.swift               → 防截屏
  └── GalleryRecognition.swift            → 文本识别