gecko-dev/xpcom/glue/BlockingResourceBase.h

345 строки
8.2 KiB
C++

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