Onchain identity controller delegation (#1431)

* rebase commit

* remove dead code

identity_iota_core/packages/iota_identity/sources/asset.move

@@ -158,7 +158,7 @@ module iota_identity::asset {
         transfer::share_object(proposal);
     }
 
-    /// Strucure that encodes the logic required to transfer an `AuthenticatedAsset`
+    /// Structure that encodes the logic required to transfer an `AuthenticatedAsset`
     /// from one address to another. The transfer can be refused by the recipient.
     public struct TransferProposal has key {
         id: UID,

identity_iota_core/packages/iota_identity/sources/controller.move

@@ -0,0 +1,144 @@
+module iota_identity::controller {
+  use iota::transfer::Receiving;
+  use iota::borrow::{Self, Referent, Borrow};
+  use iota_identity::permissions;  
+
+  public use fun delete_controller_cap as ControllerCap.delete;
+  public use fun delete_delegation_token as DelegationToken.delete;
+
+  /// This `ControllerCap` cannot delegate access.
+  const ECannotDelegate: u64 = 0;
+  // The permission of the provided `DelegationToken` are not
+  // valid to perform this operation.
+  const EInvalidPermissions: u64 = 1;
+
+  /// Event that is created when a new `DelegationToken` is minted.
+  public struct NewDelegationTokenEvent has copy, drop {
+    controller: ID,
+    token: ID,
+    permissions: u32,
+  }
+
+  /// Capability that allows to access mutative APIs of a `Multicontroller`.
+  public struct ControllerCap has key {
+    id: UID,
+    can_delegate: bool,
+    access_token: Referent<DelegationToken>,
+  }
+
+  public fun id(self: &ControllerCap): &UID {
+    &self.id
+  }
+
+  /// Borrows this `ControllerCap`'s access token.
+  public fun borrow(self: &mut ControllerCap): (DelegationToken, Borrow) {
+    self.access_token.borrow()
+  }
+
+  /// Returns the borrowed access token together with the hot potato.
+  public fun put_back(self: &mut ControllerCap, token: DelegationToken, borrow: Borrow) {
+    self.access_token.put_back(token, borrow);
+  }
+
+  /// Creates a delegation token for this controller. The created `DelegationToken`
+  /// will have full permissions. Use `delegate_with_permissions` to set or unset
+  /// specific permissions.
+  public fun delegate(self: &ControllerCap, ctx: &mut TxContext): DelegationToken {
+    assert!(self.can_delegate, ECannotDelegate);
+    new_delegation_token(self.id.to_inner(), permissions::all(), ctx)
+  }
+
+  /// Creates a delegation token for this controller, specifying the delegate's permissions.
+  public fun delegate_with_permissions(self: &ControllerCap, permissions: u32, ctx: &mut TxContext): DelegationToken {
+    assert!(self.can_delegate, ECannotDelegate);
+    new_delegation_token(self.id.to_inner(), permissions, ctx)
+  }
+
+  /// A token that allows an entity to act in a Controller's stead.
+  public struct DelegationToken has key, store {
+    id: UID,
+    permissions: u32,
+    controller: ID,
+  }
+
+  /// Returns the controller's ID of this `DelegationToken`.
+  public fun controller(self: &DelegationToken): ID {
+    self.controller
+  }
+
+  /// Returns the permissions of this `DelegationToken`.
+  public fun permissions(self: &DelegationToken): u32 {
+    self.permissions
+  }
+
+  /// Returns true if this `DelegationToken` has permission `permission`.
+  public fun has_permission(self: &DelegationToken, permission: u32): bool {
+    self.permissions & permission != 0
+  }
+
+  /// Aborts if this `DelegationToken` doesn't have permission `permission`.
+  public fun assert_has_permission(self: &DelegationToken, permission: u32) {
+    assert!(self.has_permission(permission), EInvalidPermissions)
+  }
+
+  /// Creates a new `ControllerCap`.
+  public(package) fun new(can_delegate: bool, ctx: &mut TxContext): ControllerCap {
+    let id = object::new(ctx);
+    let access_token = borrow::new(new_delegation_token(id.to_inner(), permissions::all(), ctx), ctx);
+
+    ControllerCap {
+      id,
+      access_token,
+      can_delegate,
+    }
+  }
+
+  /// Transfer a `ControllerCap`.
+  public(package) fun transfer(cap: ControllerCap, recipient: address) {
+    transfer::transfer(cap, recipient)
+  }
+
+  /// Receives a `ControllerCap`.
+  public(package) fun receive(owner: &mut UID, cap: Receiving<ControllerCap>): ControllerCap {
+    transfer::receive(owner, cap)
+  }
+
+  public(package) fun new_delegation_token(
+    controller: ID,
+    permissions: u32,
+    ctx: &mut TxContext
+  ): DelegationToken {
+    let id = object::new(ctx);
+
+    iota::event::emit(NewDelegationTokenEvent {
+      controller,
+      token: id.to_inner(),
+      permissions,
+    });
+
+    DelegationToken {
+      id,
+      controller,
+      permissions,
+    }
+  }
+
+  public(package) fun delete_controller_cap(cap: ControllerCap) {
+    let ControllerCap {
+      access_token,
+      id,
+      ..
+    } = cap;
+
+    delete_delegation_token(access_token.destroy());
+    object::delete(id);
+  }
+
+  public(package) fun delete_delegation_token(token: DelegationToken) {
+    let DelegationToken {
+      id,
+      ..
+    } = token;
+    object::delete(id);
+  }
+}