From 21a271ad96d1be5653c94fa81e32fcf3e2a957f1 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Wed, 25 Nov 2015 12:49:06 +0200
Subject: Make process move-assignable, add default c-tor

---
 butl/process     | 10 ++++++++--
 butl/process.ixx | 30 ++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/butl/process b/butl/process
index 6077ad3..e96f7ce 100644
--- a/butl/process
+++ b/butl/process
@@ -83,14 +83,20 @@ namespace butl
 
     ~process () {if (id != 0) wait ();}
 
-    // Move constructible-only type.
+    // Moveable-only type.
     //
     process (process&&);
-    process& operator= (process&&) = delete;
+    process& operator= (process&&);
 
     process (const process&) = delete;
     process& operator= (const process&) = delete;
 
+    // Create an empty or "already terminated" process. That is, id is 0
+    // and exit status is 0.
+    //
+    process ();
+
+  public:
 #ifndef _WIN32
     typedef pid_t id_type;
     typedef int status_type;
diff --git a/butl/process.ixx b/butl/process.ixx
index a049764..baf55f8 100644
--- a/butl/process.ixx
+++ b/butl/process.ixx
@@ -5,6 +5,16 @@
 namespace butl
 {
   inline process::
+  process ()
+      : id (0),
+        status (0), // This is a bit of an assumption.
+        out_fd (-1),
+        in_ofd (-1),
+        in_efd (-1)
+  {
+  }
+
+  inline process::
   process (char const* const args[], int in, int out, int err)
       : process (nullptr, args, in, out, err) {}
 
@@ -22,4 +32,24 @@ namespace butl
   {
     p.id = 0;
   }
+
+  inline process& process::
+  operator= (process&& p)
+  {
+    if (this != &p)
+    {
+      if (id != 0)
+        wait ();
+
+      id = p.id;
+      status = p.status;
+      out_fd = p.out_fd;
+      in_ofd = p.in_ofd;
+      in_efd = p.in_efd;
+
+      p.id = 0;
+    }
+
+    return *this;
+  }
 }
-- 
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