vcl/inc/opengl/zone.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #ifndef INCLUDED_VCL_INC_OPENGL_ZONE_H
  11 #define INCLUDED_VCL_INC_OPENGL_ZONE_H
  12
  13 #include <sal/config.h>
  14 #include <sal/types.h>
  15 #include <vcl/dllapi.h>
  16
  17 #include <atomic>
  18 #include <csignal>
  19 #include <type_traits>
  20
  21 class OpenGLWatchdogThread;
  22
  23 /**
  24  * We want to be able to detect if a given crash came
  25  * from the OpenGL code, so use this helper to track that.
  26  */
  27 class VCL_DLLPUBLIC OpenGLZone {
  28     friend class OpenGLWatchdogThread;
  29     friend class OpenGLSalGraphicsImpl;
  30
  31     // gnEnterCount and gnLeaveCount are accessed both from multiple threads (cf.
  32     // OpenGLWatchdogThread::execute; so need to be of atomic type) and from signal handlers (cf.
  33     // VCLExceptionSignal_impl; so need to be of lock-free atomic type).  sig_atomic_t is chosen as
  34     // the underlying type under the assumption that it is most likely to lead to an atomic type
  35     // that is actually lock-free.  However, gnEnterCount and gnLeaveCount are both monotonically
  36     // increasing, so will eventually overflow, so the underlying type better be unsigned, which
  37     // sig_atomic_t is not guaranteed to be:
  38 #if !defined ARM32 || (defined ARM32 && defined __ARM_PCS_VFP)
  39     using AtomicCounter = std::atomic<std::make_unsigned_t<std::sig_atomic_t>>;
  40     static_assert(AtomicCounter::is_always_lock_free);
  41 #else
  42     using AtomicCounter = volatile std::make_unsigned_t<std::sig_atomic_t>;
  43 #endif
  44
  45     /// how many times have we entered a GL zone
  46     static AtomicCounter gnEnterCount;
  47     /// how many times have we left a new GL zone
  48     static AtomicCounter gnLeaveCount;
  49
  50     static void enter() { gnEnterCount++; }
  51     static void leave() { gnLeaveCount++; }
  52 public:
  53      OpenGLZone() { enter(); }
  54     ~OpenGLZone() { leave(); }
  55     static bool isInZone() { return gnEnterCount != gnLeaveCount; }
  56     static void hardDisable();
  57     static void relaxWatchdogTimings();
  58 };
  59
  60 /// Create this to not only enter the zone, but set VCL context.
  61 class OpenGLVCLContextZone {
  62     OpenGLZone const aZone;
  63 public:
  64     OpenGLVCLContextZone();
  65 };
  66
  67 class VCL_DLLPUBLIC PreDefaultWinNoOpenGLZone {
  68 public:
  69     PreDefaultWinNoOpenGLZone();
  70     ~PreDefaultWinNoOpenGLZone();
  71 };
  72
  73 #endif // INCLUDED_VCL_INC_OPENGL_ZONE_H
  74
  75 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */