зеркало из https://github.com/mozilla/gecko-dev.git
339 строки
8.6 KiB
C++
339 строки
8.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_BlockingResourceBase_h
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#define mozilla_BlockingResourceBase_h
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#include "mozilla/MemoryReporting.h"
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#include "mozilla/ThreadLocal.h"
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#include "nscore.h"
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#include "nsDebug.h"
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#include "prtypes.h"
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#ifdef DEBUG
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// NB: Comment this out to enable callstack tracking.
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# define MOZ_CALLSTACK_DISABLED
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# include "prinit.h"
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# ifndef MOZ_CALLSTACK_DISABLED
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# include "mozilla/Maybe.h"
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# include "nsTArray.h"
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# endif
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#endif
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//
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// This header is not meant to be included by client code.
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//
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namespace mozilla {
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#ifdef DEBUG
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template <class T>
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class DeadlockDetector;
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#endif
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/**
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* BlockingResourceBase
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* Base class of resources that might block clients trying to acquire them.
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* Does debugging and deadlock detection in DEBUG builds.
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**/
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class BlockingResourceBase {
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public:
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// Needs to be kept in sync with kResourceTypeNames.
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enum BlockingResourceType {
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eMutex,
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eReentrantMonitor,
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eCondVar,
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eRecursiveMutex
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};
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/**
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* kResourceTypeName
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* Human-readable version of BlockingResourceType enum.
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*/
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static const char* const kResourceTypeName[];
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#ifdef DEBUG
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static size_t SizeOfDeadlockDetector(MallocSizeOf aMallocSizeOf);
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/**
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* Print
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* Write a description of this blocking resource to |aOut|. If
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* the resource appears to be currently acquired, the current
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* acquisition context is printed and true is returned.
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* Otherwise, we print the context from |aFirstSeen|, the
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* first acquisition from which the code calling |Print()|
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* became interested in us, and return false.
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*
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* *NOT* thread safe. Reads |mAcquisitionContext| without
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* synchronization, but this will not cause correctness
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* problems.
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*
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* FIXME bug 456272: hack alert: because we can't write call
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* contexts into strings, all info is written to stderr, but
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* only some info is written into |aOut|
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*/
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bool Print(nsACString& aOut) const;
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size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
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// NB: |mName| is not reported as it's expected to be a static string.
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// If we switch to a nsString it should be added to the tally.
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// |mChainPrev| is not reported because its memory is not owned.
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size_t n = aMallocSizeOf(this);
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return n;
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}
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// ``DDT'' = ``Deadlock Detector Type''
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typedef DeadlockDetector<BlockingResourceBase> DDT;
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protected:
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# ifdef MOZ_CALLSTACK_DISABLED
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typedef bool AcquisitionState;
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# else
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// Using maybe to use emplacement as the acquisition state flag; we may not
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// always get a stack trace because of possible stack walk suppression or
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// errors, hence can't use !IsEmpty() on the array itself as indication.
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static size_t const kAcquisitionStateStackSize = 24;
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typedef Maybe<AutoTArray<void*, kAcquisitionStateStackSize> >
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AcquisitionState;
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# endif
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/**
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* BlockingResourceBase
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* Initialize this blocking resource. Also hooks the resource into
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* instrumentation code.
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*
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* Thread safe.
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*
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* @param aName A meaningful, unique name that can be used in
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* error messages, et al.
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* @param aType The specific type of |this|, if any.
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**/
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BlockingResourceBase(const char* aName, BlockingResourceType aType);
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~BlockingResourceBase();
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/**
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* CheckAcquire
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*
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* Thread safe.
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**/
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void CheckAcquire();
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/**
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* Acquire
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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**/
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void Acquire(); // NS_NEEDS_RESOURCE(this)
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/**
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* Release
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* Remove this resource from the current thread's acquisition chain.
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* The resource does not have to be at the front of the chain, although
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* it is confusing to release resources in a different order than they
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* are acquired. This generates a warning.
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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**/
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void Release(); // NS_NEEDS_RESOURCE(this)
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/**
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* ResourceChainFront
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*
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* Thread safe.
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*
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* @return the front of the resource acquisition chain, i.e., the last
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* resource acquired.
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*/
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static BlockingResourceBase* ResourceChainFront() {
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return sResourceAcqnChainFront.get();
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}
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/**
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* ResourceChainPrev
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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*/
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static BlockingResourceBase* ResourceChainPrev(
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const BlockingResourceBase* aResource) {
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return aResource->mChainPrev;
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} // NS_NEEDS_RESOURCE(this)
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/**
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* ResourceChainAppend
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* Set |this| to the front of the resource acquisition chain, and link
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* |this| to |aPrev|.
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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*/
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void ResourceChainAppend(BlockingResourceBase* aPrev) {
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mChainPrev = aPrev;
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sResourceAcqnChainFront.set(this);
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} // NS_NEEDS_RESOURCE(this)
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/**
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* ResourceChainRemove
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* Remove |this| from the front of the resource acquisition chain.
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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*/
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void ResourceChainRemove() {
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NS_ASSERTION(this == ResourceChainFront(), "not at chain front");
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sResourceAcqnChainFront.set(mChainPrev);
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} // NS_NEEDS_RESOURCE(this)
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/**
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* TakeAcquisitionState
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* Return whether or not this resource was acquired and mark the resource
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* as not acquired for subsequent uses.
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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*/
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AcquisitionState TakeAcquisitionState() {
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# ifdef MOZ_CALLSTACK_DISABLED
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bool acquired = mAcquired;
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ClearAcquisitionState();
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return acquired;
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# else
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return mAcquired.take();
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# endif
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}
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/**
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* SetAcquisitionState
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* Set whether or not this resource was acquired.
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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*/
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void SetAcquisitionState(AcquisitionState&& aAcquisitionState) {
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mAcquired = std::move(aAcquisitionState);
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}
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/**
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* ClearAcquisitionState
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* Indicate this resource is not acquired.
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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*/
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void ClearAcquisitionState() {
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# ifdef MOZ_CALLSTACK_DISABLED
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mAcquired = false;
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# else
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mAcquired.reset();
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# endif
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}
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/**
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* IsAcquired
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* Indicates if this resource is acquired.
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*
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* *NOT* thread safe. Requires ownership of underlying resource.
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*/
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bool IsAcquired() const { return (bool)mAcquired; }
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/**
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* mChainPrev
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* A series of resource acquisitions creates a chain of orders. This
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* chain is implemented as a linked list; |mChainPrev| points to the
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* resource most recently Acquire()'d before this one.
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**/
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BlockingResourceBase* mChainPrev;
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private:
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/**
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* mName
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* A descriptive name for this resource. Used in error
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* messages etc.
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*/
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const char* mName;
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/**
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* mType
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* The more specific type of this resource. Used to implement
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* special semantics (e.g., reentrancy of monitors).
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**/
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BlockingResourceType mType;
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/**
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* mAcquired
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* Indicates if this resource is currently acquired.
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*/
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AcquisitionState mAcquired;
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# ifndef MOZ_CALLSTACK_DISABLED
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/**
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* mFirstSeen
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* Inidicates where this resource was first acquired.
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*/
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AcquisitionState mFirstSeen;
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# endif
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/**
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* sCallOnce
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* Ensures static members are initialized only once, and in a
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* thread-safe way.
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*/
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static PRCallOnceType sCallOnce;
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/**
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* Thread-private pointer to the front of each thread's resource
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* acquisition chain.
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*/
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static MOZ_THREAD_LOCAL(BlockingResourceBase*) sResourceAcqnChainFront;
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/**
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* sDeadlockDetector
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* Does as named.
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*/
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static DDT* sDeadlockDetector;
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/**
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* InitStatics
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* Inititialize static members of BlockingResourceBase that can't
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* be statically initialized.
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*
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* *NOT* thread safe.
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*/
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static PRStatus InitStatics();
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/**
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* Shutdown
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* Free static members.
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*
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* *NOT* thread safe.
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*/
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static void Shutdown();
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static void StackWalkCallback(uint32_t aFrameNumber, void* aPc, void* aSp,
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void* aClosure);
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static void GetStackTrace(AcquisitionState& aState,
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const void* aFirstFramePC);
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# ifdef MOZILLA_INTERNAL_API
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// so it can call BlockingResourceBase::Shutdown()
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friend void LogTerm();
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# endif // ifdef MOZILLA_INTERNAL_API
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#else // non-DEBUG implementation
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BlockingResourceBase(const char* aName, BlockingResourceType aType) {}
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~BlockingResourceBase() {}
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#endif
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};
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} // namespace mozilla
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#endif // mozilla_BlockingResourceBase_h
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