From 8a33f19986f77c57de6e5c3f307c7db8a64e1234 Mon Sep 17 00:00:00 2001
From: Kleissner <peter@kleissner.investments>
Date: Wed, 21 Apr 2021 02:49:31 +0200
Subject: [PATCH] Remove unnecessary ListIR. Removes complexity.

---
 dht/DHT Lite.go            |  6 -----
 dht/Information Request.go | 53 +++-----------------------------------
 2 files changed, 3 insertions(+), 56 deletions(-)

diff --git a/dht/DHT Lite.go b/dht/DHT Lite.go
index d10b118..d228c56 100644
--- a/dht/DHT Lite.go	
+++ b/dht/DHT Lite.go	
@@ -12,7 +12,6 @@ import (
 	"bytes"
 	"errors"
 	"sort"
-	"sync"
 	"time"
 )
 
@@ -24,10 +23,6 @@ type DHT struct {
 	// The alpha amount of nodes will be contacted in parallel for finding the target.
 	alpha int
 
-	// ListIR keeps track of all active information requests.
-	ListIR      map[string]*InformationRequest
-	listIRmutex sync.RWMutex
-
 	// Functions below must be set and provided by the caller.
 
 	// ShouldEvict determines whether the given node shall be evicted
@@ -52,7 +47,6 @@ func NewDHT(self *Node, bits, bucketSize, alpha int) *DHT {
 		ht:          newHashTable(self, bits, bucketSize),
 		alpha:       alpha,
 		TMsgTimeout: 2 * time.Second,
-		ListIR:      make(map[string]*InformationRequest),
 	}
 }
 
diff --git a/dht/Information Request.go b/dht/Information Request.go
index 035c599..fe15f81 100644
--- a/dht/Information Request.go	
+++ b/dht/Information Request.go	
@@ -44,10 +44,6 @@ func (dht *DHT) NewInformationRequest(Action int, Key []byte, Nodes []*Node) (ir
 		ActiveNodes:     uint64(len(Nodes)),
 	}
 
-	for _, node := range Nodes {
-		dht.irAdd(node.ID, ir)
-	}
-
 	return
 }
 
@@ -84,53 +80,10 @@ func (ir *InformationRequest) Terminate() {
 	close(ir.ResultChan)
 }
 
-// ActiveNodesAdd increases the number of active nodes handling this request
-func (ir *InformationRequest) ActiveNodesAdd(count uint64) {
-	atomic.AddUint64(&ir.ActiveNodes, count)
-}
-
-// ActiveNodesSub decreases the number of active nodes handling this request
-func (ir *InformationRequest) ActiveNodesSub(count uint64) {
-	if atomic.AddUint64(&ir.ActiveNodes, ^uint64(count-1)) <= 0 {
+// Done is called when a remote node is done.
+func (ir *InformationRequest) Done() {
+	if atomic.AddUint64(&ir.ActiveNodes, ^uint64(0)) <= 0 {
 		// If the counter reaches 0, it means no nodes are handling this request anymore -> terminate it.
 		ir.Terminate()
 	}
 }
-
-// ---- keep track of information requests ----
-
-// irRemove add the information request to the list
-// If a request to the same node with the same key exists, it is overwritten. This will be improved. TODO: A nonce could easily fix that?
-func (dht *DHT) irAdd(nodeID []byte, request *InformationRequest) {
-	dht.listIRmutex.Lock()
-	defer dht.listIRmutex.Unlock()
-
-	// The list only supports one request per target node and key. This should be improved.
-	lookupKey := string(nodeID) + string(request.Key)
-	dht.ListIR[lookupKey] = request
-
-	// auto remove from list upon termination
-	go func(lookupKey string, terminateChan <-chan struct{}) {
-		<-terminateChan
-		dht.irRemove(lookupKey)
-	}(lookupKey, request.TerminateSignal)
-}
-
-// irRemove removes the information request from the list
-func (dht *DHT) irRemove(lookupKey string) {
-	dht.listIRmutex.Lock()
-	defer dht.listIRmutex.Unlock()
-
-	delete(dht.ListIR, lookupKey)
-}
-
-// IRLookup looks up the information request based on the peers public key and hash
-func (dht *DHT) IRLookup(nodeID []byte, hash []byte) (request *InformationRequest) {
-	dht.listIRmutex.RLock()
-	defer dht.listIRmutex.RUnlock()
-
-	lookupKey := string(nodeID) + string(hash)
-	request = dht.ListIR[lookupKey]
-
-	return request
-}