Remove cleanups from ser-mingw.c

This removes the only cleanup from ser-mingw.c, replacing it with a
specialization of std::unique_ptr.

Tested by the buildbot.

gdb/ChangeLog
2018-06-18  Tom Tromey  <tom@tromey.com>

	* ser-mingw.c (struct pipe_state_destroyer): New.
	(pipe_state_up): New typedef.
	(cleanup_pipe_state): Remove.
	(pipe_windows_open): Use pipe_state_up.  Don't release argv.

2 files changed, 20 insertions, 20 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f80eda0..62d60c2 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
 2018-06-18  Tom Tromey  <tom@tromey.com>
 
+	* ser-mingw.c (struct pipe_state_destroyer): New.
+	(pipe_state_up): New typedef.
+	(cleanup_pipe_state): Remove.
+	(pipe_windows_open): Use pipe_state_up.  Don't release argv.
+
+2018-06-18  Tom Tromey  <tom@tromey.com>
+
 	* rust-lang.h (rust_yyerror): Don't declare.
 	* rust-lang.c (rust_language_defn): Update.
 	* rust-exp.y (yyerror): Now static.
diff --git a/gdb/ser-mingw.c b/gdb/ser-mingw.c
index d5e5aab..605a071 100644
--- a/gdb/ser-mingw.c
+++ b/gdb/ser-mingw.c
@@ -848,20 +848,20 @@ free_pipe_state (struct pipe_state *ps)
   errno = saved_errno;
 }
 
-static void
-cleanup_pipe_state (void *untyped)
+struct pipe_state_destroyer
 {
-  struct pipe_state *ps = (struct pipe_state *) untyped;
+  void operator() (pipe_state *ps) const
+  {
+    free_pipe_state (ps);
+  }
+};
 
-  free_pipe_state (ps);
-}
+typedef std::unique_ptr<pipe_state, pipe_state_destroyer> pipe_state_up;
 
 static int
 pipe_windows_open (struct serial *scb, const char *name)
 {
-  struct pipe_state *ps;
   FILE *pex_stderr;
-  struct cleanup *back_to;
 
   if (name == NULL)
     error_no_arg (_("child command"));
@@ -871,15 +871,14 @@ pipe_windows_open (struct serial *scb, const char *name)
   if (! argv[0] || argv[0][0] == '\0')
     error (_("missing child command"));
 
-  ps = make_pipe_state ();
-  back_to = make_cleanup (cleanup_pipe_state, ps);
+  pipe_state_up ps (make_pipe_state ());
 
   ps->pex = pex_init (PEX_USE_PIPES, "target remote pipe", NULL);
   if (! ps->pex)
-    goto fail;
+    return -1;
   ps->input = pex_input_pipe (ps->pex, 1);
   if (! ps->input)
-    goto fail;
+    return -1;
 
   {
     int err;
@@ -906,23 +905,17 @@ pipe_windows_open (struct serial *scb, const char *name)
 
   ps->output = pex_read_output (ps->pex, 1);
   if (! ps->output)
-    goto fail;
+    return -1;
   scb->fd = fileno (ps->output);
 
   pex_stderr = pex_read_err (ps->pex, 1);
   if (! pex_stderr)
-    goto fail;
+    return -1;
   scb->error_fd = fileno (pex_stderr);
 
-  scb->state = (void *) ps;
+  scb->state = ps.release ();
 
-  argv.release ();
-  discard_cleanups (back_to);
   return 0;
-
- fail:
-  do_cleanups (back_to);
-  return -1;
 }
 
 static int