Add hotswaps

index.js

@@ -961,7 +961,6 @@ module.exports = class Hypercore extends EventEmitter {
     if (this.opened === false) await this.opening
 
     const activeRequests = (range && range.activeRequests) || this.activeRequests
-
     return this.replicator.addRange(activeRequests, range)
   }
 

lib/replicator.js

@@ -428,6 +428,11 @@ class Peer {
     return Math.max(this.inflightRange[0], Math.round(Math.min(this.inflightRange[1], this.inflightRange[0] * scale)))
   }
 
+  getMaxHotswapInflight () {
+    const inf = this.getMaxInflight()
+    return Math.max(16, inf / 2)
+  }
+
   signalUpgrade () {
     if (this._shouldUpdateCanUpgrade() === true) this._updateCanUpgradeAndSync()
     else this.sendSync()
@@ -1838,6 +1843,13 @@ module.exports = class Replicator {
 
     b.resolve(value)
 
+    if (b.inflight.length > 0) {
+      for (let i = b.inflight.length - 1; i >= 0; i--) {
+        const req = b.inflight[i]
+        req.peer._cancelRequest(req)
+      }
+    }
+
     return true
   }
 
@@ -2161,6 +2173,28 @@ module.exports = class Replicator {
     return false
   }
 
+  _updateHotswap (peer) {
+    const maxHotswaps = peer.getMaxHotswapInflight()
+    if (!peer.isActive() || peer.inflight >= maxHotswaps) return
+
+    console.log('in update hotswap!')
+
+    let n = 0
+
+    for (const b of this._blocks) {
+      if (b.inflight.length !== 1) continue
+      if (b.inflight[0].peer === peer) continue
+
+      if (peer._requestBlock(b) === false) continue
+
+      n++
+
+      if (peer.inflight >= maxHotswaps) break
+    }
+
+    console.log('asked for', n, 'swaps')
+  }
+
   _updatePeer (peer) {
     if (!peer.isActive() || peer.inflight >= peer.getMaxInflight()) {
       return false
@@ -2230,6 +2264,10 @@ module.exports = class Replicator {
     while (this._updatePeer(peer) === true);
     while (this._updatePeerNonPrimary(peer) === true);
 
+    if (this.peers.length > 1 && this._blocks.isEmpty() === false) {
+      this._updateHotswap(peer)
+    }
+
     this._checkUpgradeIfAvailable()
     this._maybeResolveIfAvailableRanges()
   }