From 811d4229c196c1c98ff865fdfd981ef2908f6d8b Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Fri, 21 Jul 2017 09:36:05 +0200
Subject: Improve auto_rm

---
 libbutl/filesystem.hxx | 20 +++++++++-----------
 libbutl/filesystem.ixx | 13 +++++++------
 2 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/libbutl/filesystem.hxx b/libbutl/filesystem.hxx
index e23fcd3..9bf6f0c 100644
--- a/libbutl/filesystem.hxx
+++ b/libbutl/filesystem.hxx
@@ -157,21 +157,22 @@ namespace butl
   LIBBUTL_SYMEXPORT rmfile_status
   try_rmfile (const path&, bool ignore_error = false);
 
-  // Automatically try to remove the path on destruction unless cancelled.
-  // Since the non-cancelled destruction will normally happen as a result
-  // of an exception, the failure to remove the path is silently ignored.
+  // Automatically try to remove a non-empty the path on destruction unless
+  // cancelled. Since the non-cancelled destruction will normally happen as a
+  // result of an exception, the failure to remove the path is silently
+  // ignored.
   //
   template <typename P>
   struct auto_rm
   {
+    P path;
+    bool active;
+
     explicit
-    auto_rm (P p = P ()): path_ (std::move (p)) {}
+    auto_rm (P p = P (), bool a = true): path (std::move (p)), active (a) {}
 
     void
-    cancel () {path_ = P ();}
-
-    const P&
-    path () const {return path_;}
+    cancel () {active = false;}
 
     // Movable-only type. Move-assignment cancels the lhs object.
     //
@@ -181,9 +182,6 @@ namespace butl
     auto_rm& operator= (const auto_rm&) = delete;
 
     ~auto_rm ();
-
-  private:
-    P path_;
   };
 
   using auto_rmfile = auto_rm<path>;
diff --git a/libbutl/filesystem.ixx b/libbutl/filesystem.ixx
index a53aa47..a618d5b 100644
--- a/libbutl/filesystem.ixx
+++ b/libbutl/filesystem.ixx
@@ -44,9 +44,9 @@ namespace butl
   template <typename P>
   inline auto_rm<P>::
   auto_rm (auto_rm&& x)
-      : path_ (std::move (x.path_))
+      : path (std::move (x.path)), active (x.active)
   {
-    x.cancel ();
+    x.active = false;
   }
 
   template <typename P>
@@ -55,8 +55,9 @@ namespace butl
   {
     if (this != &x)
     {
-      path_ = std::move (x.path_);
-      x.cancel ();
+      path = std::move (x.path);
+      active = x.active;
+      x.active = false;
     }
 
     return *this;
@@ -64,11 +65,11 @@ namespace butl
 
   template <>
   inline auto_rm<path>::
-  ~auto_rm () {if (!path_.empty ()) try_rmfile (path_, true);}
+  ~auto_rm () {if (active && !path.empty ()) try_rmfile (path, true);}
 
   template <>
   inline auto_rm<dir_path>::
-  ~auto_rm () {if (!path_.empty ()) try_rmdir_r (path_, true);}
+  ~auto_rm () {if (active && !path.empty ()) try_rmdir_r (path, true);}
 
   // cpflags
   //
-- 
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