From ea16391beffca62e3dc602452c0adc29c18c32e9 Mon Sep 17 00:00:00 2001
From: whyrusleeping <why@ipfs.io>
Date: Wed, 7 Feb 2024 12:21:12 -0800
Subject: [PATCH] WIP: global block cache for carstore

---
 carstore/bs.go | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/carstore/bs.go b/carstore/bs.go
index 0095c9fd7..efddcc442 100644
--- a/carstore/bs.go
+++ b/carstore/bs.go
@@ -45,6 +45,8 @@ type CarStore struct {
 
 	lscLk          sync.Mutex
 	lastShardCache map[models.Uid]*CarShard
+
+	globalCache map[cid.Cid]blockformat.Block
 }
 
 func NewCarStore(meta *gorm.DB, root string) (*CarStore, error) {
@@ -68,6 +70,7 @@ func NewCarStore(meta *gorm.DB, root string) (*CarStore, error) {
 		meta:           meta,
 		rootDir:        root,
 		lastShardCache: make(map[models.Uid]*CarShard),
+		globalCache:    make(map[cid.Cid]blockformat.Block),
 	}, nil
 }
 
@@ -138,6 +141,10 @@ func unpackCids(b []byte) ([]cid.Cid, error) {
 	return out, nil
 }
 
+func (cs *CarStore) SetGlobalCacheEntry(k cid.Cid, v blockformat.Block) {
+	cs.globalCache[k] = v
+}
+
 type userView struct {
 	cs   *CarStore
 	user models.Uid
@@ -594,6 +601,11 @@ func (ds *DeltaSession) Get(ctx context.Context, c cid.Cid) (blockformat.Block,
 		return b, nil
 	}
 
+	gcb, ok := ds.cs.globalCache[c]
+	if ok {
+		return gcb, nil
+	}
+
 	return ds.base.Get(ctx, c)
 }
 
@@ -603,6 +615,11 @@ func (ds *DeltaSession) Has(ctx context.Context, c cid.Cid) (bool, error) {
 		return true, nil
 	}
 
+	_, ok = ds.cs.globalCache[c]
+	if ok {
+		return true, nil
+	}
+
 	return ds.base.Has(ctx, c)
 }
 
@@ -616,6 +633,11 @@ func (ds *DeltaSession) GetSize(ctx context.Context, c cid.Cid) (int, error) {
 		return len(b.RawData()), nil
 	}
 
+	gcb, ok := ds.cs.globalCache[c]
+	if ok {
+		return len(gcb.RawData()), nil
+	}
+
 	return ds.base.GetSize(ctx, c)
 }