[Ada] Add push/pop capability in Output
Arnaud Charlet
charlet@adacore.com
Thu Jul 23 13:02:04 GMT 2020
Add the capability to use the Write_* procedures in an environment where
you want to write debugging info but still use them to write to other
files (such a C source files).
[changelog]
* output.ads (Push_Output, Pop_Output): New procedures.
* output.adb (FD_Array, FD_Stack, FD_Stack_Idx): New type and vars.
(Push_Output, Pop_Output): New procedures.
Tested on x86_64-pc-linux-gnu, commited on trunk
---
output.adb | 29 +++++++++++++++++++++++++++++
output.ads | 9 +++++++++
2 files changed, 38 insertions(+)
diff --git output.adb output.adb
index d36aac8..971819b 100644
--- output.adb
+++ output.adb
@@ -45,6 +45,13 @@ package body Output is
Current_FD : File_Descriptor := Standout;
-- File descriptor for current output
+ type FD_Array is array (Nat range 1 .. 3) of File_Descriptor;
+ FD_Stack : FD_Array;
+ FD_Stack_Idx : Nat := FD_Array'First - 1;
+ -- Maintain a small stack for Push_Output and Pop_Output. We'd normally
+ -- use Table for this and allow an unlimited depth, but we're the target
+ -- of a pragma Elaborate_All in Table, so we can't use it here.
+
Special_Output_Proc : Output_Proc := null;
-- Record argument to last call to Set_Special_Output. If this is
-- non-null, then we are in special output mode.
@@ -228,6 +235,28 @@ procedure Outdent is
(Cur_Indentation - Indentation_Amount) mod Indentation_Limit;
end Outdent;
+ ----------------
+ -- Pop_Output --
+ ----------------
+
+ procedure Pop_Output is
+ begin
+ pragma Assert (FD_Stack_Idx >= FD_Array'First);
+ Current_FD := FD_Stack (FD_Stack_Idx);
+ FD_Stack_Idx := FD_Stack_Idx - 1;
+ end Pop_Output;
+
+ -----------------
+ -- Push_Output --
+ -----------------
+
+ procedure Push_Output is
+ begin
+ pragma Assert (FD_Stack_Idx < FD_Array'Last);
+ FD_Stack_Idx := FD_Stack_Idx + 1;
+ FD_Stack (FD_Stack_Idx) := Current_FD;
+ end Push_Output;
+
---------------------------
-- Restore_Output_Buffer --
---------------------------
diff --git output.ads output.ads
index 4574cce..55d308a 100644
--- output.ads
+++ output.ads
@@ -95,6 +95,15 @@ procedure Set_Output (FD : File_Descriptor);
-- output will appear on the given file descriptor only after special
-- output has been cancelled.
+ procedure Push_Output;
+ -- Saves the current output destination on a stack, but leaves it
+ -- unchanged. This subprogram only supports a small stack and is normally
+ -- used with a depth of one.
+
+ procedure Pop_Output;
+ -- Changes the current output destination to be the last output destination
+ -- popped using Push_Output.
+
procedure Indent;
-- Increases the current indentation level. Whenever a line is written
-- (triggered by Eol), an appropriate amount of whitespace is added to the
--
2.1.4
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