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Lib: fix a bug with diagnostic output

Browse source 
The header "format-cout.hpp" offers a convenience function
to print pretty much any object or data in human readable form.
However, the formatter for pointers used within this framework
switched std::cout into hexadecimal display of numbers and failed
to clean-up this state.

Since the "stickyness" of IOS stream manipulators is generally a problem,
we now provide a RAII helper to capture the previous stream state and
automatically restore it when leaving the scope.
This commit is contained in:
Fischlurch 2022-09-27 01:51:21 +02:00
parent 8fdde735d4
commit f393780845
7 changed files with 263 additions and 6 deletions
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2
src/lib/format-obj.cpp
View file

@ -42,6 +42,7 @@
#include "lib/error.hpp"
#include "lib/format-obj.hpp"
#include "lib/ios-savepoint.hpp"
//#include "lib/format-string.hpp"
#include "lib/unique-malloc-owner.hpp"
#include "lib/symbol.hpp"
@ -375,6 +376,7 @@ namespace util {
ostream&
showAddr (ostream& stream, void const* addr)
{
IosSavepoint save{stream};
size_t suffix_modulus = size_t(1) << DIAGNOSTICS_ADDRESS_SUFFIX_LEN * 8;
return stream << "╲"
<< hex

82
src/lib/ios-savepoint.hpp Normal file
View file

@ -0,0 +1,82 @@
/*
IOS-SAVEPOINT.hpp - capture and restore std::ostream format settings
Copyright (C) Lumiera.org
2022, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file ios-savepoint.hpp
** Capture previous settings of an `std::ostream` and restore them when leaving scope.
** The stream manipulators of the IOS-Framework from the C++ standard lib allow to adjust
** various aspects of output formatting for following data fed to the output stream.
** Unfortunately many of these settings are _sticky_ and thus may "taint" common
** output streams like `std::cout`. By planting this RAII capsule into a local scope,
** the internal settings of an output stream can be recorded and restored automatically,
** once control flow leaves the scope.
** @remark based on this [stackoverflow] by «[qbert220]», 2013
**
** @see IosSavepoint_test
**
** [qbert220]: https://stackoverflow.com/users/617617/qbert220
** [stackoverflow]: https://stackoverflow.com/a/18822888 "Restore state of `std::cout` after manipulating it"
**
**
*/
#ifndef LIB_IOS_SAVEPOINT_H
#define LIB_IOS_SAVEPOINT_H
#include "lib/nocopy.hpp"
#include <ostream>
namespace util {
/**
* RAII helper to capture and restore
* output stream format settings.
*/
class IosSavepoint
: MoveOnly
{
std::ostream& theStream_;
std::ios_base::fmtflags prevFlags_;
char fillChar_;
public:
explicit
IosSavepoint(std::ostream& stream_to_capture)
: theStream_{stream_to_capture}
, prevFlags_{theStream_.flags()}
, fillChar_{theStream_.fill()}
{ }
~IosSavepoint()
{
theStream_.flags(prevFlags_);
theStream_.fill(fillChar_);
}
};
} // namespace util
#endif /*LIB_IOS_SAVEPOINT_H*/

4
src/lib/meta/function.hpp
View file

@ -85,7 +85,7 @@ namespace meta{
* The following explicit specialisations handle the other cases, which are
* not objects, but primitive types (function (member) pointers and references).
* @remarks The key trick of this solution is to rely on `decltype` of `operator()`
* and was proposed 10/2011 by user "[kennytm]" in this [stackoverflow].
* and was proposed 10/2011 by user «[kennytm]» in this [stackoverflow].
* @note for a member pointer to function, only the actual arguments in the
* function signature are reflected. But if you bind such a member
* pointer into a `std::function`, an additional first parameter
@ -102,7 +102,7 @@ namespace meta{
* @see FunctionSignature_test
*
* [kennytm]: http://stackoverflow.com/users/224671/kennytm
* [stackoverflow] : http://stackoverflow.com/questions/7943525/is-it-possible-to-figure-out-the-parameter-type-and-return-type-of-a-lambda/7943765#7943765 "answer on stackoverflow"
* [stackoverflow]: http://stackoverflow.com/questions/7943525/is-it-possible-to-figure-out-the-parameter-type-and-return-type-of-a-lambda/7943765#7943765 "figure out parameter and return type of a Lambda"
*/
template<typename FUN, typename SEL =void>
struct _Fun

6
src/stage/ui-bus.hpp
View file

@ -38,7 +38,7 @@
**
** # Rationale
** The UI-Bus acts as a **mediating backbone**, impersonating the role
** of the _Model_ and the _Controller_ in the [MVC-Pattern]in common UI architecture.
** of the _Model_ and the _Controller_ in the [MVC-Pattern] in common UI architecture.
**
** The MVC-Pattern as such is fine, and probably the best we know for construction of
** user interfaces. But it doesn't scale well towards the integration into a larger and
@ -66,9 +66,9 @@
** directed towards individual elements. The interactions at the bus are closely interrelated
** with the [elementary UI-Element operations](\ref tangible.hpp).
**
** - *act*: send a [GenNode] representing the action
** - *act*: send a \ref GenNode representing the action
** - the ID is either a globally registered command-ID or an explicitly
** ["opened"](\ref steam::control::SessionCommand::cycle(Symbol,string)) command instance ID.
** [opened](\ref steam::control::SessionCommand::cycle(Symbol,string const&)) command instance ID.
** - the payload is a Record<GenNode> holding the actual command arguments
** - on reception, an _instance_ (anonymous clone copy) of the command is created, bound
** with the arguments and handed over to the SteamDispatcher to be enqueued for execution.

15
tests/15library.tests
View file

@ -424,6 +424,21 @@ return: 0
END
TEST "IOS restore format" IosSavepoint_test <<END
out-lit: 0x2a
out-lit: 42
out-lit: ******************42
out-lit: 42
out-lit: 2a
out-lit: 052
out-lit: 2a
out-lit: 42
out-lit: 1234
out-lit: Tilt
out-lit: 42
END
TEST "configurable Factory" MultiFact_test <<END
END

136
tests/library/ios-savepoint-test.cpp Normal file
View file

@ -0,0 +1,136 @@
/*
IosSavepoint(Test) - manipulate and restore output stream formatting
Copyright (C) Lumiera.org
2022, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
* *****************************************************/
/** @file ios-savepoint-test.cpp
** unit test \ref IosSavepoint_test
*/
#include "lib/test/run.hpp"
#include "lib/format-cout.hpp"
#include "lib/ios-savepoint.hpp"
#include <string>
using std::string;
namespace util {
namespace test {
/***************************************************************************//**
* @test verifies capturing and restoring of std::ostream formatting state.
* @see ios-savepoint.hpp
*/
class IosSavepoint_test
: public Test
{
void
run (Arg)
{
switchToHex();
__verifySane();
setFill();
__verifySane();
nested();
__verifySane();
try {
restoreAfterException();
} catch(...){
cout << "Tilt" <<endl;
}
__verifySane();
}
/** verify that original state is restored */
void
__verifySane()
{
cout << std::setw(10) << 42 <<endl;
}
/** @test verify that hexadecimal output is cleared */
void
switchToHex()
{
IosSavepoint save{cout};
cout << std::hex
<< std::showbase
<< 42 <<endl;
}
/** @test verify that a custom fill character is cleared */
void
setFill()
{
IosSavepoint save{cout};
cout << std::setfill('*')
<< std::setw(20)
<< 42 <<endl;
}
/** @test verify usage in nested scopes */
void
nested()
{
IosSavepoint save{cout};
cout << std::hex << 42 <<endl;
{
IosSavepoint inner(cout);
cout << std::oct << std::showbase << 42 <<endl;
}
cout << 42 <<endl;
}
/** @test verify clean-up happens even in case of an exception */
void
restoreAfterException()
{
auto boom = []() -> float
{ throw 42; };
IosSavepoint save{cout};
cout << std::hexfloat
<< 1234
<< endl
<< boom()
<< endl;
}
};
LAUNCHER (IosSavepoint_test, "unit common");
}} // namespace util::test

24
wiki/thinkPad.ichthyo.mm
View file

@ -18862,8 +18862,30 @@
<node CREATED="1664152996461" ID="ID_1521476415" MODIFIED="1664153038156" TEXT="und dieser f&#xfc;hrt jeweils zu einer anderen Ausdehnung des Hintergrunds (Flackern?)">
<icon BUILTIN="broken-line"/>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1664153044266" ID="ID_175410634" MODIFIED="1664153998416" TEXT="und das Debugging per cout gibt Hexzahlen aus">
<node COLOR="#435e98" CREATED="1664153044266" FOLDED="true" ID="ID_175410634" MODIFIED="1664236010809" TEXT="und das Debugging per cout gibt Hexzahlen aus">
<icon BUILTIN="broken-line"/>
<node CREATED="1664235646216" ID="ID_1679047596" MODIFIED="1664236010445" TEXT="Ursache waren naiv verwendete stream-Manipulatoren">
<richcontent TYPE="NOTE"><html>
<head>
</head>
<body>
<p>
Die meisten IOS-Stream-Manipulatoren sind &#187;sticky&#171;, d.h. sie ver&#228;ndern per Seiteneffekt den Zustand im jeweiligen ostream. Ich hatte eine Methode zum Ausgeben einer Addresse, eingebaut im to-String-Framework, und diese hat std::output auf Hex-Ausgabe umgeschaltet. Erstaunlich da&#223; ich das jahrelang nicht gemerkt habe!
</p>
</body>
</html></richcontent>
<icon BUILTIN="idea"/>
</node>
<node COLOR="#338800" CREATED="1664235664755" ID="ID_1756013187" MODIFIED="1664235705945" TEXT="RAII-Helper-Klasse, die ostream-Format-Zustand speichern und restaurieren kann">
<icon BUILTIN="button_ok"/>
</node>
<node COLOR="#338800" CREATED="1664235714143" ID="ID_1375500060" MODIFIED="1664235720200" TEXT="mit Test abgedeckt">
<icon BUILTIN="button_ok"/>
</node>
<node COLOR="#338800" CREATED="1664235720902" ID="ID_558625134" MODIFIED="1664235875234" TEXT="Bug in format-obj.cpp damit gefixt">
<icon BUILTIN="button_ok"/>
</node>
</node>
</node>
</node>