From 5d460e8815a8b49915da7ffabccc4a8b96a61acc Mon Sep 17 00:00:00 2001
From: Alex Potsides <alex@achingbrain.net>
Date: Tue, 4 Oct 2022 16:20:52 +0100
Subject: [PATCH] feat: add acceptIncomingConnection to ConnectionManager
 (#295)

* feat: add acceptIncomingConnection to ConnectionManager

In order to check we can accept an incoming connection before exchanging
PeerIds, add a method to the ConnectionManager interface that can
be called by the upgrader.

* chore: return boolean
---
 packages/interface-connection-manager/src/index.ts | 10 +++++++++-
 packages/interface-mocks/src/connection-manager.ts |  4 ++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/packages/interface-connection-manager/src/index.ts b/packages/interface-connection-manager/src/index.ts
index 0f34d583e..0eadaebb0 100644
--- a/packages/interface-connection-manager/src/index.ts
+++ b/packages/interface-connection-manager/src/index.ts
@@ -1,6 +1,6 @@
 import type { AbortOptions } from '@libp2p/interfaces'
 import type { EventEmitter } from '@libp2p/interfaces/events'
-import type { Connection } from '@libp2p/interface-connection'
+import type { Connection, MultiaddrConnection } from '@libp2p/interface-connection'
 import type { PeerId } from '@libp2p/interface-peer-id'
 import type { Multiaddr } from '@multiformats/multiaddr'
 
@@ -24,6 +24,14 @@ export interface ConnectionManager extends EventEmitter<ConnectionManagerEvents>
    * Close our connections to a peer
    */
   closeConnections: (peer: PeerId) => Promise<void>
+
+  /**
+   * Invoked after an incoming connection is opened but before PeerIds are
+   * exchanged, this lets the ConnectionManager check we have sufficient
+   * resources to accept the connection in which case it will return true,
+   * otherwise it will return false.
+   */
+  acceptIncomingConnection: (maConn: MultiaddrConnection) => Promise<boolean>
 }
 
 export interface Dialer {
diff --git a/packages/interface-mocks/src/connection-manager.ts b/packages/interface-mocks/src/connection-manager.ts
index 12e9ee05a..32eeb41f1 100644
--- a/packages/interface-mocks/src/connection-manager.ts
+++ b/packages/interface-mocks/src/connection-manager.ts
@@ -134,6 +134,10 @@ class MockConnectionManager extends EventEmitter<ConnectionManagerEvents> implem
 
     await componentsB.getConnectionManager().closeConnections(this.components.getPeerId())
   }
+
+  async acceptIncomingConnection (): Promise<boolean> {
+    return true
+  }
 }
 
 export function mockConnectionManager () {