xpcom/build/LateWriteChecks.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_LateWriteChecks_h
   8 #define mozilla_LateWriteChecks_h
   9
  10 // This file, along with LateWriteChecks.cpp, serves to check for and report
  11 // late writes. The idea is discover writes to the file system that happens
  12 // during shutdown such that these maybe be moved forward and the process may be
  13 // killed without waiting for static destructors.
  14
  15 namespace mozilla {
  16
  17 /** Different shutdown check modes */
  18 enum ShutdownChecksMode {
  19   SCM_CRASH,  /** Crash on shutdown check failure */
  20   SCM_RECORD, /** Record shutdown check violations */
  21   SCM_NOTHING /** Don't attempt any shutdown checks */
  22 };
  23
  24 /**
  25  * Current shutdown check mode.
  26  * This variable is defined and initialized in nsAppRunner.cpp
  27  */
  28 extern ShutdownChecksMode gShutdownChecks;
  29
  30 /**
  31  * Allocate structures and acquire information from XPCOM necessary to do late
  32  * write checks. This function must be invoked before BeginLateWriteChecks()
  33  * and before XPCOM has stopped working.
  34  */
  35 void InitLateWriteChecks();
  36
  37 /**
  38  * Begin recording all writes as late-writes. This function should be called
  39  * when all legitimate writes have occurred. This function does not rely on
  40  * XPCOM as it is designed to be invoked during XPCOM shutdown.
  41  *
  42  * For late-write checks to work you must initialize one or more backends that
  43  * reports IO through the IOInterposer API. PoisonIOInterposer would probably
  44  * be the backend of choice in this case.
  45  *
  46  * Note: BeginLateWriteChecks() must have been invoked before this function.
  47  */
  48 void BeginLateWriteChecks();
  49
  50 /**
  51  * Stop recording all writes as late-writes, call this function when you want
  52  * late-write checks to stop. I.e. exception handling, or the special case on
  53  * Mac described in bug 826029.
  54  */
  55 void StopLateWriteChecks();
  56
  57 /**
  58  * Temporarily suspend late write checks for the current thread. This is useful
  59  * if you're about to perform a write, but it would be fine if this write were
  60  * interrupted or skipped during a fast shutdown.
  61  */
  62 void PushSuspendLateWriteChecks();
  63
  64 /**
  65  * Resume late write checks for the current thread, assuming an ancestor in the
  66  * call stack hasn't also pushed a suspension.
  67  */
  68 void PopSuspendLateWriteChecks();
  69
  70 class MOZ_RAII AutoSuspendLateWriteChecks {
  71  public:
  72   AutoSuspendLateWriteChecks() { PushSuspendLateWriteChecks(); }
  73   ~AutoSuspendLateWriteChecks() { PopSuspendLateWriteChecks(); }
  74 };
  75
  76 }  // namespace mozilla
  77
  78 #endif  // mozilla_LateWriteChecks_h