From a703e2d1f2474ba5f82311ddb2a68d2668affed6 Mon Sep 17 00:00:00 2001
From: Jeromy <jeromyj@gmail.com>
Date: Sat, 3 Feb 2018 14:45:11 -0800
Subject: [PATCH] comments

License: MIT
Signed-off-by: Jeromy <jeromyj@gmail.com>
---
 merkledag/merkledag.go | 1 +
 merkledag/readonly.go  | 4 ++++
 merkledag/session.go   | 3 +++
 3 files changed, 8 insertions(+)

diff --git a/merkledag/merkledag.go b/merkledag/merkledag.go
index 080abcb898a..1ee6ccfb671 100644
--- a/merkledag/merkledag.go
+++ b/merkledag/merkledag.go
@@ -146,6 +146,7 @@ func (sg *sesGetter) GetMany(ctx context.Context, keys []*cid.Cid) <-chan *ipld.
 	return getNodesFromBG(ctx, sg.bs, keys)
 }
 
+// Session returns a NodeGetter using a new session for block fetches.
 func (ds *dagService) Session(ctx context.Context) ipld.NodeGetter {
 	return &sesGetter{bserv.NewSession(ctx, ds.Blocks)}
 }
diff --git a/merkledag/readonly.go b/merkledag/readonly.go
index e2344061700..1fd48eff95c 100644
--- a/merkledag/readonly.go
+++ b/merkledag/readonly.go
@@ -6,8 +6,12 @@ import (
 	ipld "gx/ipfs/Qme5bWv7wtjUNGsK2BNGVUFPKiuxWrsqrtvYwCLRw8YFES/go-ipld-format"
 )
 
+// ErrReadOnly is used when a read-only datastructure is written to.
 var ErrReadOnly = fmt.Errorf("cannot write to readonly DAGService")
 
+// NewReadOnlyDagService takes a NodeGetter, and returns a full DAGService
+// implementation that returns ErrReadOnly when its 'write' methods are
+// invoked.
 func NewReadOnlyDagService(ng ipld.NodeGetter) ipld.DAGService {
 	return &ComboService{
 		Read:  ng,
diff --git a/merkledag/session.go b/merkledag/session.go
index 50015dc3a54..fe0df24d0ec 100644
--- a/merkledag/session.go
+++ b/merkledag/session.go
@@ -6,10 +6,13 @@ import (
 	ipld "gx/ipfs/Qme5bWv7wtjUNGsK2BNGVUFPKiuxWrsqrtvYwCLRw8YFES/go-ipld-format"
 )
 
+// SessionMaker is an object that can generate a new fetching session.
 type SessionMaker interface {
 	Session(context.Context) ipld.NodeGetter
 }
 
+// NewSession returns a session backed NodeGetter if the given NodeGetter
+// implements SessionMaker.
 func NewSession(ctx context.Context, g ipld.NodeGetter) ipld.NodeGetter {
 	if sm, ok := g.(SessionMaker); ok {
 		return sm.Session(ctx)