From 3eedbf41885fdcee258afec1cde93bda3aa6c02b Mon Sep 17 00:00:00 2001
From: mcrakhman <rakhmanov.m@gmail.com>
Date: Wed, 10 Aug 2022 12:53:15 +0200
Subject: [PATCH] Add read and write methods for treecache

---
 service/api/service.go                        |  2 +-
 service/sync/document/service.go              |  2 +-
 service/sync/requesthandler/requesthandler.go |  6 ++---
 service/treecache/service.go                  | 23 ++++++++++++++++---
 4 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/service/api/service.go b/service/api/service.go
index 8ab7eb26..0f8e5453 100644
--- a/service/api/service.go
+++ b/service/api/service.go
@@ -79,7 +79,7 @@ func (s *service) treeDump(w http.ResponseWriter, req *http.Request) {
 		dump   string
 		err    error
 	)
-	err = s.treeCache.Do(context.Background(), treeId, func(tree acltree.ACLTree) error {
+	err = s.treeCache.DoWrite(context.Background(), treeId, func(tree acltree.ACLTree) error {
 		dump, err = tree.DebugDump()
 		if err != nil {
 			return err
diff --git a/service/sync/document/service.go b/service/sync/document/service.go
index b684e64b..ba9df31c 100644
--- a/service/sync/document/service.go
+++ b/service/sync/document/service.go
@@ -71,7 +71,7 @@ func (s *service) UpdateDocument(ctx context.Context, id, text string) (err erro
 	log.With(zap.String("id", id), zap.String("text", text)).
 		Debug("updating document")
 
-	err = s.treeCache.Do(ctx, id, func(tree acltree.ACLTree) error {
+	err = s.treeCache.DoWrite(ctx, id, func(tree acltree.ACLTree) error {
 		ch, err = tree.AddContent(ctx, func(builder acltree.ChangeBuilder) error {
 			builder.AddChangeContent(
 				&testchangepb.PlainTextChangeData{
diff --git a/service/sync/requesthandler/requesthandler.go b/service/sync/requesthandler/requesthandler.go
index 2eb70551..12908a24 100644
--- a/service/sync/requesthandler/requesthandler.go
+++ b/service/sync/requesthandler/requesthandler.go
@@ -79,7 +79,7 @@ func (r *requestHandler) HandleHeadUpdate(ctx context.Context, senderId string,
 	log.With(zap.String("peerId", senderId), zap.String("treeId", update.TreeId)).
 		Debug("processing head update")
 
-	err = r.treeCache.Do(ctx, update.TreeId, func(tree acltree.ACLTree) error {
+	err = r.treeCache.DoWrite(ctx, update.TreeId, func(tree acltree.ACLTree) error {
 		// TODO: check if we already have those changes
 		result, err = tree.AddRawChanges(ctx, update.Changes...)
 		if err != nil {
@@ -133,7 +133,7 @@ func (r *requestHandler) HandleFullSyncRequest(ctx context.Context, senderId str
 	log.With(zap.String("peerId", senderId), zap.String("treeId", request.TreeId)).
 		Debug("processing full sync request")
 
-	err = r.treeCache.Do(ctx, request.TreeId, func(tree acltree.ACLTree) error {
+	err = r.treeCache.DoWrite(ctx, request.TreeId, func(tree acltree.ACLTree) error {
 		// TODO: check if we already have those changes
 		// if we have non-empty request
 		if len(request.Heads) != 0 {
@@ -177,7 +177,7 @@ func (r *requestHandler) HandleFullSyncResponse(ctx context.Context, senderId st
 	log.With(zap.String("peerId", senderId), zap.String("treeId", response.TreeId)).
 		Debug("processing full sync response")
 
-	err = r.treeCache.Do(ctx, response.TreeId, func(tree acltree.ACLTree) error {
+	err = r.treeCache.DoWrite(ctx, response.TreeId, func(tree acltree.ACLTree) error {
 		// TODO: check if we already have those changes
 		result, err = tree.AddRawChanges(ctx, response.Changes...)
 		if err != nil {
diff --git a/service/treecache/service.go b/service/treecache/service.go
index 687300f0..dc334ea3 100644
--- a/service/treecache/service.go
+++ b/service/treecache/service.go
@@ -22,7 +22,8 @@ type ChangeBuildFunc = func(builder acltree.ChangeBuilder) error
 var log = logger.NewNamed("treecache")
 
 type Service interface {
-	Do(ctx context.Context, treeId string, f ACLTreeFunc) error
+	DoWrite(ctx context.Context, treeId string, f ACLTreeFunc) error
+	DoRead(ctx context.Context, treeId string, f ACLTreeFunc) error
 	Add(ctx context.Context, treeId string, header *treepb.TreeHeader, changes []*aclpb.RawChange, f ACLTreeFunc) error
 	Create(ctx context.Context, build ChangeBuildFunc, f ACLTreeFunc) error
 }
@@ -49,10 +50,10 @@ func (s *service) Create(ctx context.Context, build ChangeBuildFunc, f ACLTreeFu
 		return err
 	}
 
-	return s.Do(ctx, id, f)
+	return s.DoWrite(ctx, id, f)
 }
 
-func (s *service) Do(ctx context.Context, treeId string, f ACLTreeFunc) error {
+func (s *service) DoWrite(ctx context.Context, treeId string, f ACLTreeFunc) error {
 	log.
 		With(zap.String("treeId", treeId)).
 		Debug("requesting tree from cache to perform operation")
@@ -68,6 +69,22 @@ func (s *service) Do(ctx context.Context, treeId string, f ACLTreeFunc) error {
 	return f(tree.(acltree.ACLTree))
 }
 
+func (s *service) DoRead(ctx context.Context, treeId string, f ACLTreeFunc) error {
+	log.
+		With(zap.String("treeId", treeId)).
+		Debug("requesting tree from cache to perform operation")
+
+	tree, err := s.cache.Get(ctx, treeId)
+	defer s.cache.Release(treeId)
+	if err != nil {
+		return err
+	}
+	aclTree := tree.(acltree.ACLTree)
+	aclTree.RLock()
+	defer aclTree.RUnlock()
+	return f(tree.(acltree.ACLTree))
+}
+
 func (s *service) Add(ctx context.Context, treeId string, header *treepb.TreeHeader, changes []*aclpb.RawChange, f ACLTreeFunc) error {
 	log.
 		With(zap.String("treeId", treeId), zap.Int("len(changes)", len(changes))).