mixpool: Remove unused exported methods

One exception: we are keeping RemoveConfirmedMixes.  This method behaves
similarly to RemoveSpentPRs but removes mixes that completed with a confirmed
coinjoin transaction matching any of the provided hashes.  This may be used
later by wallet to remove mixes that include transaction hashes in the merkle
tree, while dcrd can just provide the mined transactions themselves and remove
anything that double spends a PR UTXO.

mixing/mixclient/client.go

@@ -538,7 +538,7 @@ func (c *Client) removeUnresponsiveDuringEpoch(prs []*wire.MsgMixPairReq, prevEp
 }
 
 func (c *Client) epochTicker(ctx context.Context) error {
-	prevPRs := c.mixpool.MixPRs(nil)
+	prevPRs := c.mixpool.MixPRs()
 
 	// Wait for the next epoch + the KE timeout + extra duration for local
 	// clock differences, then remove any previous pair requests that are

mixing/mixpool/mixpool.go

@@ -214,19 +214,6 @@ func (p *Pool) Epoch() time.Duration {
 	return p.epoch
 }
 
-// MixPRHashes returns the hashes of all MixPR messages recorded by the pool.
-// This data is provided to peers requesting initial state of the mixpool.
-func (p *Pool) MixPRHashes() []chainhash.Hash {
-	p.mtx.RLock()
-	hashes := make([]chainhash.Hash, 0, len(p.prs))
-	for hash := range p.prs {
-		hashes = append(hashes, hash)
-	}
-	p.mtx.RUnlock()
-
-	return hashes
-}
-
 // Message searches the mixing pool for a message by its hash.
 func (p *Pool) Message(query *chainhash.Hash) (mixing.Message, error) {
 	p.mtx.RLock()
@@ -253,60 +240,25 @@ func (p *Pool) HaveMessage(query *chainhash.Hash) bool {
 	return ok
 }
 
-// MixPR searches the mixing pool for a PR message by its hash.
-func (p *Pool) MixPR(query *chainhash.Hash) (*wire.MsgMixPairReq, error) {
-	var pr *wire.MsgMixPairReq
-
-	p.mtx.RLock()
-	pr = p.prs[*query]
-	p.mtx.RUnlock()
-
-	if pr == nil {
-		return nil, fmt.Errorf("PR message not found")
-	}
-
-	return pr, nil
-}
-
-// MixPRs returns all MixPR messages with hashes matching the query.  Unknown
-// messages are ignored.
-//
-// If query is nil, all PRs are returned.
+// MixPRs returns all MixPR messages.
 //
-// In both cases, any expired PRs that are still internally tracked by the
-// mixpool for ongoing sessions are excluded from the result set.
-func (p *Pool) MixPRs(query []chainhash.Hash) []*wire.MsgMixPairReq {
+// Any expired PRs that are still internally tracked by the mixpool for
+// ongoing sessions are excluded from the result set.
+func (p *Pool) MixPRs() []*wire.MsgMixPairReq {
 	p.mtx.Lock()
 	defer p.mtx.Unlock()
 
 	p.removeConfirmedRuns()
 
-	if query == nil {
-		res := make([]*wire.MsgMixPairReq, 0, len(p.prs))
-		for _, pr := range p.prs {
-			// Exclude expired but not yet removed PRs.
-			if pr.Expiry <= p.expireHeight {
-				continue
-			}
-
-			res = append(res, pr)
+	res := make([]*wire.MsgMixPairReq, 0, len(p.prs))
+	for _, pr := range p.prs {
+		// Exclude expired but not yet removed PRs.
+		if pr.Expiry <= p.expireHeight {
+			continue
 		}
-		return res
-	}
 
-	res := make([]*wire.MsgMixPairReq, 0, len(query))
-	for i := range query {
-		pr, ok := p.prs[query[i]]
-		if ok {
-			// Exclude expired but not yet removed PRs.
-			if pr.Expiry <= p.expireHeight {
-				continue
-			}
-
-			res = append(res, pr)
-		}
+		res = append(res, pr)
 	}
-
 	return res
 }