[gcc(refs/users/guojiufu/heads/guojiufu-branch)] [Ada] AI12-0350 Swap for Indefinite_Holders

[Jiu Fu Guo]

https://gcc.gnu.org/g:5052a270c0f685998a3456d87d441a59bc1d67ee

commit 5052a270c0f685998a3456d87d441a59bc1d67ee
Author: Arnaud Charlet <charlet@adacore.com>
Date:   Mon Mar 23 04:49:13 2020 -0400

    [Ada] AI12-0350 Swap for Indefinite_Holders
    
    2020-06-12  Arnaud Charlet  <charlet@adacore.com>
    
    gcc/ada/
    
            * libgnat/a-coinho.ads, libgnat/a-coinho.adb,
            libgnat/a-coinho__shared.ads, libgnat/a-coinho__shared.adb
            (Swap): New procedure.

Diff:
---
 gcc/ada/libgnat/a-coinho.adb         | 24 ++++++++++++++++++++++++
 gcc/ada/libgnat/a-coinho.ads         |  2 ++
 gcc/ada/libgnat/a-coinho__shared.adb | 24 ++++++++++++++++++++++++
 gcc/ada/libgnat/a-coinho__shared.ads |  2 ++
 4 files changed, 52 insertions(+)

diff --git a/gcc/ada/libgnat/a-coinho.adb b/gcc/ada/libgnat/a-coinho.adb
index ef58e9e556d..c5da9432dd9 100644
--- a/gcc/ada/libgnat/a-coinho.adb
+++ b/gcc/ada/libgnat/a-coinho.adb
@@ -304,6 +304,30 @@ package body Ada.Containers.Indefinite_Holders is
       end;
    end Replace_Element;
 
+   ----------
+   -- Swap --
+   ----------
+
+   procedure Swap (Left, Right : in out Holder) is
+   begin
+      if Left.Busy /= 0 then
+         raise Program_Error with "attempt to tamper with elements";
+      end if;
+
+      if Right.Busy /= 0 then
+         raise Program_Error with "attempt to tamper with elements";
+      end if;
+
+      if Left.Element /= Right.Element then
+         declare
+            Tmp : constant Element_Access := Left.Element;
+         begin
+            Left.Element := Right.Element;
+            Right.Element := Tmp;
+         end;
+      end if;
+   end Swap;
+
    ---------------
    -- To_Holder --
    ---------------
diff --git a/gcc/ada/libgnat/a-coinho.ads b/gcc/ada/libgnat/a-coinho.ads
index af22cbf70e5..bf6165e954d 100644
--- a/gcc/ada/libgnat/a-coinho.ads
+++ b/gcc/ada/libgnat/a-coinho.ads
@@ -92,6 +92,8 @@ package Ada.Containers.Indefinite_Holders is
 
    procedure Move (Target : in out Holder; Source : in out Holder);
 
+   procedure Swap (Left, Right : in out Holder);
+
 private
 
    use Ada.Finalization;
diff --git a/gcc/ada/libgnat/a-coinho__shared.adb b/gcc/ada/libgnat/a-coinho__shared.adb
index bfeb6adfc65..43f5d52f7db 100644
--- a/gcc/ada/libgnat/a-coinho__shared.adb
+++ b/gcc/ada/libgnat/a-coinho__shared.adb
@@ -426,6 +426,30 @@ package body Ada.Containers.Indefinite_Holders is
       end if;
    end Replace_Element;
 
+   ----------
+   -- Swap --
+   ----------
+
+   procedure Swap (Left, Right : in out Holder) is
+   begin
+      if Left.Busy /= 0 then
+         raise Program_Error with "attempt to tamper with elements";
+      end if;
+
+      if Right.Busy /= 0 then
+         raise Program_Error with "attempt to tamper with elements";
+      end if;
+
+      if Left.Reference /= Right.Reference then
+         declare
+            Tmp : constant Shared_Holder_Access := Left.Reference;
+         begin
+            Left.Reference := Right.Reference;
+            Right.Reference := Tmp;
+         end;
+      end if;
+   end Swap;
+
    ---------------
    -- To_Holder --
    ---------------
diff --git a/gcc/ada/libgnat/a-coinho__shared.ads b/gcc/ada/libgnat/a-coinho__shared.ads
index af2e7e0e343..0345b5ee0db 100644
--- a/gcc/ada/libgnat/a-coinho__shared.ads
+++ b/gcc/ada/libgnat/a-coinho__shared.ads
@@ -96,6 +96,8 @@ package Ada.Containers.Indefinite_Holders is
 
    procedure Move (Target : in out Holder; Source : in out Holder);
 
+   procedure Swap (Left, Right : in out Holder);
+
 private
 
    use Ada.Finalization;