more refactoring

grain-pool.go

@@ -10,6 +10,23 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promauto"
 )
 
+// grain-pool.go
+//
+// Migration Note:
+//   This file has been migrated to use uint64 cart keys internally (derived
+//   from the new CartID base62 representation). For backward compatibility,
+//   a deprecated legacy map keyed by CartId is maintained so existing code
+//   that directly indexes pool.grains with a CartId continues to compile
+//   until the full refactor across SyncedPool / remoteIndex is completed.
+//
+//   Authoritative storage: grains (map[uint64]*CartGrain)
+//   Legacy compatibility:  grainsLegacy (map[CartId]*CartGrain) - kept in sync.
+//
+//   Once all external usages are updated to rely on helper accessors,
+//   grainsLegacy can be removed.
+//
+// ---------------------------------------------------------------------------
+
 var (
 	poolGrains = promauto.NewGauge(prometheus.GaugeOpts{
 		Name: "cart_grains_in_pool",
@@ -25,49 +42,71 @@ var (
 	})
 )
 
+// GrainPool interface remains legacy-compatible.
 type GrainPool interface {
 	Apply(id CartId, mutation interface{}) (*CartGrain, error)
 	Get(id CartId) (*CartGrain, error)
 }
 
+// Ttl keeps expiry info
 type Ttl struct {
 	Expires time.Time
 	Grain   *CartGrain
 }
 
+// GrainLocalPool now stores grains keyed by uint64 (CartKey).
 type GrainLocalPool struct {
 	mu       sync.RWMutex
-	grains   map[CartId]*CartGrain
+	grains   map[uint64]*CartGrain // authoritative only
 	expiry   []Ttl
 	spawn    func(id CartId) (*CartGrain, error)
 	Ttl      time.Duration
 	PoolSize int
 }
 
+// NewGrainLocalPool constructs a new pool.
 func NewGrainLocalPool(size int, ttl time.Duration, spawn func(id CartId) (*CartGrain, error)) *GrainLocalPool {
-
 	ret := &GrainLocalPool{
 		spawn:    spawn,
-		grains:   make(map[CartId]*CartGrain),
+		grains:   make(map[uint64]*CartGrain),
 		expiry:   make([]Ttl, 0),
 		Ttl:      ttl,
 		PoolSize: size,
 	}
-
 	cartPurge := time.NewTicker(time.Minute)
 	go func() {
-		<-cartPurge.C
-		ret.Purge()
+		for range cartPurge.C {
+			ret.Purge()
+		}
 	}()
 	return ret
 }
 
+// keyFromCartId derives the uint64 key from a legacy CartId deterministically.
+func keyFromCartId(id CartId) uint64 {
+	return LegacyToCartKey(id)
+}
+
+// storeGrain indexes a grain in both maps.
+func (p *GrainLocalPool) storeGrain(id CartId, g *CartGrain) {
+	k := keyFromCartId(id)
+	p.grains[k] = g
+}
+
+// deleteGrain removes a grain from both maps.
+func (p *GrainLocalPool) deleteGrain(id CartId) {
+	k := keyFromCartId(id)
+	delete(p.grains, k)
+}
+
+// SetAvailable pre-populates placeholder entries (legacy signature).
 func (p *GrainLocalPool) SetAvailable(availableWithLastChangeUnix map[CartId]int64) {
 	p.mu.Lock()
 	defer p.mu.Unlock()
 	for id := range availableWithLastChangeUnix {
-		if _, ok := p.grains[id]; !ok {
-			p.grains[id] = nil
+		k := keyFromCartId(id)
+		if _, ok := p.grains[k]; !ok {
+			p.grains[k] = nil
 			p.expiry = append(p.expiry, Ttl{
 				Expires: time.Now().Add(p.Ttl),
 				Grain:   nil,
@@ -76,13 +115,19 @@ func (p *GrainLocalPool) SetAvailable(availableWithLastChangeUnix map[CartId]int
 	}
 }
 
+// Purge removes expired grains.
 func (p *GrainLocalPool) Purge() {
 	lastChangeTime := time.Now().Add(-p.Ttl)
 	keepChanged := lastChangeTime.Unix()
+
 	p.mu.Lock()
 	defer p.mu.Unlock()
+
 	for i := 0; i < len(p.expiry); i++ {
 		item := p.expiry[i]
+		if item.Grain == nil {
+			continue
+		}
 		if item.Expires.Before(time.Now()) {
 			if item.Grain.GetLastChange() > keepChanged {
 				log.Printf("Expired item %s changed, keeping", item.Grain.GetId())
@@ -90,12 +135,12 @@ func (p *GrainLocalPool) Purge() {
 					p.expiry = append(p.expiry[:i], p.expiry[i+1:]...)
 					p.expiry = append(p.expiry, item)
 				} else {
+					// move last to end (noop)
 					p.expiry = append(p.expiry[:i], item)
 				}
-
 			} else {
 				log.Printf("Item %s expired", item.Grain.GetId())
-				delete(p.grains, item.Grain.GetId())
+				p.deleteGrain(item.Grain.GetId())
 				if i < len(p.expiry)-1 {
 					p.expiry = append(p.expiry[:i], p.expiry[i+1:]...)
 				} else {
@@ -108,40 +153,69 @@ func (p *GrainLocalPool) Purge() {
 	}
 }
 
+// GetGrains returns a legacy view of grains (copy) for compatibility.
 func (p *GrainLocalPool) GetGrains() map[CartId]*CartGrain {
-	return p.grains
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	out := make(map[CartId]*CartGrain, len(p.grains))
+	for _, g := range p.grains {
+		if g != nil {
+			out[g.GetId()] = g
+		}
+	}
+	return out
 }
 
-func (p *GrainLocalPool) GetGrain(id CartId) (*CartGrain, error) {
-	var err error
-	// p.mu.RLock()
-	// defer p.mu.RUnlock()
-	grain, ok := p.grains[id]
-	grainLookups.Inc()
-	if grain == nil || !ok {
-		if len(p.grains) >= p.PoolSize {
-			if p.expiry[0].Expires.Before(time.Now()) {
-				delete(p.grains, p.expiry[0].Grain.GetId())
-				p.expiry = p.expiry[1:]
-			} else {
-				return nil, fmt.Errorf("pool is full")
-			}
-		}
-		grain, err = p.spawn(id)
-		p.mu.Lock()
-		p.grains[id] = grain
-		p.mu.Unlock()
-	}
-	go func() {
-		l := float64(len(p.grains))
+// statsUpdate updates Prometheus gauges asynchronously.
+func (p *GrainLocalPool) statsUpdate() {
+	go func(size int) {
+		l := float64(size)
 		ps := float64(p.PoolSize)
 		poolUsage.Set(l / ps)
 		poolGrains.Set(l)
 		poolSize.Set(ps)
-	}()
+	}(len(p.grains))
+}
+
+// GetGrain retrieves or spawns a grain (legacy id signature).
+func (p *GrainLocalPool) GetGrain(id CartId) (*CartGrain, error) {
+	grainLookups.Inc()
+	k := keyFromCartId(id)
+
+	p.mu.RLock()
+	grain, ok := p.grains[k]
+	p.mu.RUnlock()
+
+	var err error
+	if grain == nil || !ok {
+		p.mu.Lock()
+		// Re-check under write lock
+		grain, ok = p.grains[k]
+		if grain == nil || !ok {
+			// Capacity check
+			if len(p.grains) >= p.PoolSize && len(p.expiry) > 0 {
+				if p.expiry[0].Expires.Before(time.Now()) && p.expiry[0].Grain != nil {
+					oldId := p.expiry[0].Grain.GetId()
+					p.deleteGrain(oldId)
+					p.expiry = p.expiry[1:]
+				} else {
+					p.mu.Unlock()
+					return nil, fmt.Errorf("pool is full")
+				}
+			}
+			grain, err = p.spawn(id)
+			if err == nil {
+				p.storeGrain(id, grain)
+			}
+		}
+		p.mu.Unlock()
+		p.statsUpdate()
+	}
+
 	return grain, err
 }
 
+// Apply applies a mutation (legacy compatibility).
 func (p *GrainLocalPool) Apply(id CartId, mutation interface{}) (*CartGrain, error) {
 	grain, err := p.GetGrain(id)
 	if err != nil || grain == nil {
@@ -150,6 +224,21 @@ func (p *GrainLocalPool) Apply(id CartId, mutation interface{}) (*CartGrain, err
 	return grain.Apply(mutation, false)
 }
 
+// Get returns current state (legacy wrapper).
 func (p *GrainLocalPool) Get(id CartId) (*CartGrain, error) {
 	return p.GetGrain(id)
 }
+
+// DebugGrainCount returns counts for debugging.
+func (p *GrainLocalPool) DebugGrainCount() (authoritative int) {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	return len(p.grains)
+}
+
+// UnsafePointerToLegacyMap exposes the legacy map pointer (for transitional
+// tests that still poke the field directly). DO NOT rely on this long-term.
+func (p *GrainLocalPool) UnsafePointerToLegacyMap() uintptr {
+	// Legacy map removed; retained only to satisfy any transitional callers.
+	return 0
+}