From b7f32cea30174e391027fecc9d431ca16b2f87c2 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 25 Oct 2022 10:24:53 +0200
Subject: All passing to process ownership to one end of pipe

---
 libbutl/process-run.cxx |  2 +-
 libbutl/process-run.txx | 10 ++++++----
 libbutl/process.cxx     |  1 -
 libbutl/process.hxx     | 28 ++++++++++++++++++++++++----
 libbutl/process.ixx     | 36 ++++++++++++++++++++++++++++++++++++
 5 files changed, 67 insertions(+), 10 deletions(-)

(limited to 'libbutl')

diff --git a/libbutl/process-run.cxx b/libbutl/process-run.cxx
index a5014f6..b044ea1 100644
--- a/libbutl/process-run.cxx
+++ b/libbutl/process-run.cxx
@@ -24,7 +24,7 @@ namespace butl
     try
     {
       return process (pp, cmd,
-                      in, out, err,
+                      move (in), move (out), move (err),
                       cwd != nullptr ? cwd->string ().c_str () : nullptr,
                       envvars);
     }
diff --git a/libbutl/process-run.txx b/libbutl/process-run.txx
index 8e6ca57..67426f0 100644
--- a/libbutl/process-run.txx
+++ b/libbutl/process-run.txx
@@ -87,21 +87,21 @@ namespace butl
   // valid file descriptor.
   //
   inline process::pipe
-  process_stdin (const process::pipe& v)
+  process_stdin (process::pipe v)
   {
     assert (v.in >= 0);
     return v;
   }
 
   inline process::pipe
-  process_stdout (const process::pipe& v)
+  process_stdout (process::pipe v)
   {
     assert (v.out >= 0);
     return v;
   }
 
   inline process::pipe
-  process_stderr (const process::pipe& v)
+  process_stderr (process::pipe v)
   {
     assert (v.out >= 0);
     return v;
@@ -170,7 +170,9 @@ namespace butl
     return process_start (env.cwd,
                           *env.path, cmd.data (),
                           env.vars,
-                          in_i, out_i, err_i);
+                          std::move (in_i),
+                          std::move (out_i),
+                          std::move (err_i));
   }
 
   template <typename C,
diff --git a/libbutl/process.cxx b/libbutl/process.cxx
index a19719f..aee4508 100644
--- a/libbutl/process.cxx
+++ b/libbutl/process.cxx
@@ -1794,7 +1794,6 @@ namespace butl
 
       using namespace chrono;
 
-
       // Retry for about 1 hour.
       //
       system_clock::duration timeout (1h);
diff --git a/libbutl/process.hxx b/libbutl/process.hxx
index 47cc507..cf5bcd8 100644
--- a/libbutl/process.hxx
+++ b/libbutl/process.hxx
@@ -298,21 +298,41 @@ namespace butl
              const char* const* envvars = nullptr);
 
     // If the descriptors are pipes that you have created, then you should use
-    // this constructor instead to communicate this information.
+    // this constructor instead to communicate this information (the parent
+    // end may need to be "probed" on Windows).
     //
     // For generality, if the "other" end of the pipe is -1, then assume this
     // is not a pipe.
     //
     struct pipe
     {
-      int in  = -1;
-      int out = -1;
-
       pipe () = default;
       pipe (int i, int o): in (i), out (o) {}
 
       explicit
       pipe (const fdpipe& p): in (p.in.get ()), out (p.out.get ()) {}
+
+      // Transfer ownership to one end of the pipe.
+      //
+      pipe (auto_fd i, int o): in (i.release ()), out (o), own_in (true) {}
+      pipe (int i, auto_fd o): in (i), out (o.release ()), own_out (true) {}
+
+      // Moveable-only type.
+      //
+      pipe (pipe&&);
+      pipe& operator= (pipe&&);
+
+      pipe (const pipe&) = delete;
+      pipe& operator= (const pipe&) = delete;
+
+      ~pipe ();
+
+    public:
+      int in  = -1;
+      int out = -1;
+
+      bool own_in = false;
+      bool own_out = false;
     };
 
     process (const process_path&, const char* [],
diff --git a/libbutl/process.ixx b/libbutl/process.ixx
index 256454b..0f04127 100644
--- a/libbutl/process.ixx
+++ b/libbutl/process.ixx
@@ -124,6 +124,42 @@ namespace butl
   }
 #endif
 
+  // process::pipe
+  //
+  inline process::pipe::
+  pipe (pipe&& p)
+      : in (p.in), out (p.out), own_in (p.own_in), own_out (p.own_out)
+  {
+    p.in = p.out = -1;
+  }
+
+  inline process::pipe& process::pipe::
+  operator= (pipe&& p)
+  {
+    if (this != &p)
+    {
+      int d (own_in ? in : own_out ? out : -1);
+      if (d != -1)
+        fdclose (d);
+
+      in = p.in;
+      out = p.out;
+      own_in = p.own_in;
+      own_out = p.own_out;
+
+      p.in = p.out = -1;
+    }
+    return *this;
+  }
+
+  inline process::pipe::
+  ~pipe ()
+  {
+    int d (own_in ? in : own_out ? out : -1);
+    if (d != -1)
+      fdclose (d);
+  }
+
   // process
   //
 #ifndef _WIN32
-- 
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