From d40c50f80a7e2dfb67daa7078893ae298299af97 Mon Sep 17 00:00:00 2001
From: Adam Jensen <acjensen@gmail.com>
Date: Sun, 13 May 2018 10:27:38 -0400
Subject: [PATCH] Add length deferrer support to composer

---
 composer.go  | 36 ++++++++++++++++++++++++++----------
 composer.mgo |  4 ++++
 2 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/composer.go b/composer.go
index f15b38a..9ec8aa2 100644
--- a/composer.go
+++ b/composer.go
@@ -6,16 +6,18 @@ package tusd
 type StoreComposer struct {
 	Core DataStore
 
-	UsesTerminater bool
-	Terminater     TerminaterDataStore
-	UsesFinisher   bool
-	Finisher       FinisherDataStore
-	UsesLocker     bool
-	Locker         LockerDataStore
-	UsesGetReader  bool
-	GetReader      GetReaderDataStore
-	UsesConcater   bool
-	Concater       ConcaterDataStore
+	UsesTerminater     bool
+	Terminater         TerminaterDataStore
+	UsesFinisher       bool
+	Finisher           FinisherDataStore
+	UsesLocker         bool
+	Locker             LockerDataStore
+	UsesGetReader      bool
+	GetReader          GetReaderDataStore
+	UsesConcater       bool
+	Concater           ConcaterDataStore
+	UsesLengthDeferrer bool
+	LengthDeferrer     LengthDeferrerDataStore
 }
 
 // NewStoreComposer creates a new and empty store composer.
@@ -45,6 +47,9 @@ func newStoreComposerFromDataStore(store DataStore) *StoreComposer {
 	if mod, ok := store.(ConcaterDataStore); ok {
 		composer.UseConcater(mod)
 	}
+	if mod, ok := store.(LengthDeferrerDataStore); ok {
+		composer.UseLengthDeferrer(mod)
+	}
 
 	return composer
 }
@@ -90,6 +95,12 @@ func (store *StoreComposer) Capabilities() string {
 	} else {
 		str += "✗"
 	}
+	str += ` LengthDeferrer: `
+	if store.UsesLengthDeferrer {
+		str += "✓"
+	} else {
+		str += "✗"
+	}
 
 	return str
 }
@@ -120,3 +131,8 @@ func (store *StoreComposer) UseConcater(ext ConcaterDataStore) {
 	store.UsesConcater = ext != nil
 	store.Concater = ext
 }
+
+func (store *StoreComposer) UseLengthDeferrer(ext LengthDeferrerDataStore) {
+	store.UsesLengthDeferrer = ext != nil
+	store.LengthDeferrer = ext
+}
diff --git a/composer.mgo b/composer.mgo
index 32db7ea..247cdb8 100644
--- a/composer.mgo
+++ b/composer.mgo
@@ -31,6 +31,7 @@ type StoreComposer struct {
   USE_FIELD(Locker)
   USE_FIELD(GetReader)
   USE_FIELD(Concater)
+  USE_FIELD(LengthDeferrer)
 }
 
 // NewStoreComposer creates a new and empty store composer.
@@ -50,6 +51,7 @@ func newStoreComposerFromDataStore(store DataStore) *StoreComposer {
   USE_FROM(Locker)
   USE_FROM(GetReader)
   USE_FROM(Concater)
+  USE_FROM(LengthDeferrer)
 
   return composer
 }
@@ -70,6 +72,7 @@ func (store *StoreComposer) Capabilities() string {
   USE_CAP(Locker)
   USE_CAP(GetReader)
   USE_CAP(Concater)
+  USE_CAP(LengthDeferrer)
 
   return str
 }
@@ -85,3 +88,4 @@ USE_FUNC(Finisher)
 USE_FUNC(Locker)
 USE_FUNC(GetReader)
 USE_FUNC(Concater)
+USE_FUNC(LengthDeferrer)