Signal-iOS/SignalMessaging/groups/GroupsV2Changes.swift
2020-05-19 15:49:36 -03:00

312 lines
14 KiB
Swift

//
// Copyright (c) 2020 Open Whisper Systems. All rights reserved.
//
import Foundation
import SignalServiceKit
import ZKGroup
public struct ChangedGroupModel {
public let oldGroupModel: TSGroupModelV2
public let newGroupModel: TSGroupModelV2
// newDisappearingMessageToken is only set of DM state changed.
public let newDisappearingMessageToken: DisappearingMessageToken?
public let changeAuthorUuid: UUID
public let profileKeys: [UUID: Data]
public init(oldGroupModel: TSGroupModelV2,
newGroupModel: TSGroupModelV2,
newDisappearingMessageToken: DisappearingMessageToken?,
changeAuthorUuid: UUID,
profileKeys: [UUID: Data]) {
self.oldGroupModel = oldGroupModel
self.newGroupModel = newGroupModel
self.newDisappearingMessageToken = newDisappearingMessageToken
self.changeAuthorUuid = changeAuthorUuid
self.profileKeys = profileKeys
}
}
// MARK: -
public class GroupsV2Changes {
// GroupsV2Changes has one responsibility: applying incremental
// changes to group models. It should exactly mimic the behavior
// of the service. Applying these "diffs" allow us to do two things:
//
// * Update groups without the burden of contacting the service.
// * Stay aligned with service state... mostly.
//
// We can always deviate due to a bug or due to new "change actions"
// that the local client doesn't know about. We're not versioning
// the changes so if we introduce a breaking changes to the "change
// actions" we'll need to roll out support for the new actions
// before they go live.
//
// This method applies a single set of "change actions" to a group
// model, thereby deriving a new group model whose revision is
// exactly 1 higher.
class func applyChangesToGroupModel(groupThread: TSGroupThread,
changeActionsProto: GroupsProtoGroupChangeActions,
downloadedAvatars: GroupV2DownloadedAvatars,
transaction: SDSAnyReadTransaction) throws -> ChangedGroupModel {
guard let oldGroupModel = groupThread.groupModel as? TSGroupModelV2 else {
throw OWSAssertionError("Invalid group model.")
}
let groupV2Params = try oldGroupModel.groupV2Params()
// Many change actions have author info, e.g. addedByUserID. But we can
// safely assume that all actions in the "change actions" have the same author.
guard let changeAuthorUuidData = changeActionsProto.sourceUuid else {
throw OWSAssertionError("Missing changeAuthorUuid.")
}
let changeAuthorUuid = try groupV2Params.uuid(forUserId: changeAuthorUuidData)
guard changeActionsProto.hasRevision else {
throw OWSAssertionError("Missing revision.")
}
let newRevision = changeActionsProto.revision
guard newRevision == oldGroupModel.revision + 1 else {
throw OWSAssertionError("Unexpected revision: \(newRevision) != \(oldGroupModel.revision + 1).")
}
var newGroupName: String? = oldGroupModel.groupName
var newAvatarData: Data? = oldGroupModel.groupAvatarData
var newAvatarUrlPath = oldGroupModel.avatarUrlPath
let oldGroupMembership = oldGroupModel.groupMembership
var groupMembershipBuilder = oldGroupMembership.asBuilder
let oldGroupAccess = oldGroupModel.access
var newMembersAccess = oldGroupAccess.members
var newAttributesAccess = oldGroupAccess.attributes
// This client can learn of profile keys from parsing group state protos.
// After parsing, we should fill in profileKeys in the profile manager.
var profileKeys = [UUID: Data]()
for action in changeActionsProto.addMembers {
guard let member = action.added else {
throw OWSAssertionError("Missing member.")
}
guard let userId = member.userID else {
throw OWSAssertionError("Missing userID.")
}
guard let protoRole = member.role else {
throw OWSAssertionError("Missing role.")
}
guard let role = TSGroupMemberRole.role(for: protoRole) else {
throw OWSAssertionError("Invalid role: \(protoRole.rawValue)")
}
let uuid = try groupV2Params.uuid(forUserId: userId)
let address = SignalServiceAddress(uuid: uuid)
guard !oldGroupMembership.allUsers.contains(address) else {
throw OWSAssertionError("Invalid membership.")
}
groupMembershipBuilder.remove(address)
groupMembershipBuilder.addNonPendingMember(address, role: role)
guard let profileKeyCiphertextData = member.profileKey else {
throw OWSAssertionError("Missing profileKeyCiphertext.")
}
let profileKeyCiphertext = try ProfileKeyCiphertext(contents: [UInt8](profileKeyCiphertextData))
let profileKey = try groupV2Params.profileKey(forProfileKeyCiphertext: profileKeyCiphertext,
uuid: uuid)
profileKeys[uuid] = profileKey
}
for action in changeActionsProto.deleteMembers {
guard let userId = action.deletedUserID else {
throw OWSAssertionError("Missing userID.")
}
let uuid = try groupV2Params.uuid(forUserId: userId)
let address = SignalServiceAddress(uuid: uuid)
guard oldGroupMembership.nonPendingMembers.contains(address) else {
throw OWSAssertionError("Invalid membership.")
}
groupMembershipBuilder.remove(address)
}
for action in changeActionsProto.modifyMemberRoles {
guard let userId = action.userID else {
throw OWSAssertionError("Missing userID.")
}
guard let protoRole = action.role else {
throw OWSAssertionError("Missing role.")
}
guard let role = TSGroupMemberRole.role(for: protoRole) else {
throw OWSAssertionError("Invalid role: \(protoRole.rawValue)")
}
let uuid = try groupV2Params.uuid(forUserId: userId)
let address = SignalServiceAddress(uuid: uuid)
guard oldGroupMembership.nonPendingMembers.contains(address) else {
throw OWSAssertionError("Invalid membership.")
}
groupMembershipBuilder.remove(address)
groupMembershipBuilder.addNonPendingMember(address, role: role)
}
for action in changeActionsProto.modifyMemberProfileKeys {
guard let presentationData = action.presentation else {
throw OWSAssertionError("Missing presentation.")
}
let presentation = try ProfileKeyCredentialPresentation(contents: [UInt8](presentationData))
let uuidCiphertext = try presentation.getUuidCiphertext()
let uuid = try groupV2Params.uuid(forUuidCiphertext: uuidCiphertext)
let address = SignalServiceAddress(uuid: uuid)
guard oldGroupMembership.nonPendingMembers.contains(address) else {
throw OWSAssertionError("Invalid membership.")
}
let profileKeyCiphertext = try presentation.getProfileKeyCiphertext()
let profileKey = try groupV2Params.profileKey(forProfileKeyCiphertext: profileKeyCiphertext,
uuid: uuid)
profileKeys[uuid] = profileKey
}
for action in changeActionsProto.addPendingMembers {
guard let pendingMember = action.added else {
throw OWSAssertionError("Missing pendingMember.")
}
guard let member = pendingMember.member else {
throw OWSAssertionError("Missing member.")
}
guard let userId = member.userID else {
throw OWSAssertionError("Missing userID.")
}
guard let protoRole = member.role else {
throw OWSAssertionError("Missing role.")
}
guard let role = TSGroupMemberRole.role(for: protoRole) else {
throw OWSAssertionError("Invalid role: \(protoRole.rawValue)")
}
guard let addedByUserID = pendingMember.addedByUserID else {
throw OWSAssertionError("Group pending member missing addedByUserID.")
}
let uuid: UUID
let addedByUuid: UUID
do {
uuid = try groupV2Params.uuid(forUserId: userId)
addedByUuid = try groupV2Params.uuid(forUserId: addedByUserID)
} catch {
owsFailDebug("Error parsing uuid: \(error)")
continue
}
let address = SignalServiceAddress(uuid: uuid)
guard !oldGroupMembership.allUsers.contains(address) else {
throw OWSAssertionError("Invalid membership.")
}
groupMembershipBuilder.remove(address)
groupMembershipBuilder.addPendingMember(address, role: role, addedByUuid: addedByUuid)
}
for action in changeActionsProto.deletePendingMembers {
guard let userId = action.deletedUserID else {
throw OWSAssertionError("Missing userID.")
}
let uuid = try groupV2Params.uuid(forUserId: userId)
let address = SignalServiceAddress(uuid: uuid)
guard oldGroupMembership.pendingMembers.contains(address) else {
throw OWSAssertionError("Invalid membership.")
}
groupMembershipBuilder.remove(address)
}
for action in changeActionsProto.promotePendingMembers {
guard let presentationData = action.presentation else {
throw OWSAssertionError("Missing presentation.")
}
let presentation = try ProfileKeyCredentialPresentation(contents: [UInt8](presentationData))
let uuidCiphertext = try presentation.getUuidCiphertext()
let uuid = try groupV2Params.uuid(forUuidCiphertext: uuidCiphertext)
let address = SignalServiceAddress(uuid: uuid)
guard oldGroupMembership.pendingMembers.contains(address) else {
throw OWSAssertionError("Invalid membership.")
}
guard !oldGroupMembership.nonPendingMembers.contains(address) else {
throw OWSAssertionError("Invalid membership.")
}
guard let role = oldGroupMembership.role(for: address) else {
throw OWSAssertionError("Missing role.")
}
groupMembershipBuilder.remove(address)
groupMembershipBuilder.addNonPendingMember(address, role: role)
let profileKeyCiphertext = try presentation.getProfileKeyCiphertext()
let profileKey = try groupV2Params.profileKey(forProfileKeyCiphertext: profileKeyCiphertext,
uuid: uuid)
profileKeys[uuid] = profileKey
}
if let action = changeActionsProto.modifyTitle {
// Change clears or updates the group title.
newGroupName = groupV2Params.decryptGroupName(action.title)
}
if let action = changeActionsProto.modifyAvatar {
if let avatarUrl = action.avatar,
!avatarUrl.isEmpty {
do {
newAvatarData = try downloadedAvatars.avatarData(for: avatarUrl)
newAvatarUrlPath = avatarUrl
} catch {
owsFailDebug("Missing or invalid avatar: \(error)")
newAvatarData = nil
newAvatarUrlPath = nil
}
} else {
// Change clears the group avatar.
newAvatarData = nil
newAvatarUrlPath = nil
}
}
var newDisappearingMessageToken: DisappearingMessageToken?
if let action = changeActionsProto.modifyDisappearingMessagesTimer {
// If the timer blob is not populated or has zero duration,
// disappearing messages should be disabled.
newDisappearingMessageToken = groupV2Params.decryptDisappearingMessagesTimer(action.timer)
}
if let action = changeActionsProto.modifyAttributesAccess {
guard let protoAccess = action.attributesAccess else {
throw OWSAssertionError("Missing access.")
}
newAttributesAccess = GroupAccess.groupV2Access(forProtoAccess: protoAccess)
}
if let action = changeActionsProto.modifyMemberAccess {
guard let protoAccess = action.membersAccess else {
throw OWSAssertionError("Missing access.")
}
newMembersAccess = GroupAccess.groupV2Access(forProtoAccess: protoAccess)
}
let newGroupMembership = groupMembershipBuilder.build()
let newGroupAccess = GroupAccess(members: newMembersAccess, attributes: newAttributesAccess)
var builder = oldGroupModel.asBuilder
builder.name = newGroupName
builder.avatarData = newAvatarData
builder.groupMembership = newGroupMembership
builder.groupAccess = newGroupAccess
builder.groupV2Revision = newRevision
builder.avatarUrlPath = newAvatarUrlPath
let newGroupModel = try builder.buildAsV2(transaction: transaction)
return ChangedGroupModel(oldGroupModel: oldGroupModel,
newGroupModel: newGroupModel,
newDisappearingMessageToken: newDisappearingMessageToken,
changeAuthorUuid: changeAuthorUuid,
profileKeys: profileKeys)
}
}