From 755bea8112eb50d223823c35364f7474b9a8434b Mon Sep 17 00:00:00 2001
From: zhangyi <zhangyi@hangsheng.com.cn>
Date: Thu, 28 Mar 2019 16:23:31 +0800
Subject: [PATCH] add attach/detach for shm

---
 include/shm.h |  4 +++-
 src/shm.cpp   | 11 +++++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/include/shm.h b/include/shm.h
index b5206c6..a20731e 100644
--- a/include/shm.h
+++ b/include/shm.h
@@ -38,7 +38,9 @@ public:
     void release();
 
     void* get() const;
-    id_t dismiss();
+
+    void attach(id_t);
+    id_t detach();
 
 private:
     class handle_;
diff --git a/src/shm.cpp b/src/shm.cpp
index 3b035a7..71e3a2a 100644
--- a/src/shm.cpp
+++ b/src/shm.cpp
@@ -66,7 +66,7 @@ bool handle::acquire(char const * name, std::size_t size, unsigned mode) {
 
 void handle::release() {
     if (!valid()) return;
-    shm::release(dismiss());
+    shm::release(detach());
 }
 
 void* handle::get() const {
@@ -74,7 +74,14 @@ void* handle::get() const {
     return impl(p_)->m_;
 }
 
-id_t handle::dismiss() {
+void handle::attach(id_t id) {
+    if (id == nullptr) return;
+    release();
+    impl(p_)->id_ = id;
+    impl(p_)->m_  = shm::get_mem(impl(p_)->id_, &(impl(p_)->s_));
+}
+
+id_t handle::detach() {
     if (!valid()) return nullptr;
     auto old = impl(p_)->id_;
     impl(p_)->id_ = nullptr;