summaryrefslogtreecommitdiffstats
path: root/xpcom/glue/BlockingResourceBase.h
diff options
context:
space:
mode:
Diffstat (limited to 'xpcom/glue/BlockingResourceBase.h')
-rw-r--r--xpcom/glue/BlockingResourceBase.h344
1 files changed, 344 insertions, 0 deletions
diff --git a/xpcom/glue/BlockingResourceBase.h b/xpcom/glue/BlockingResourceBase.h
new file mode 100644
index 000000000..d70fbcbbf
--- /dev/null
+++ b/xpcom/glue/BlockingResourceBase.h
@@ -0,0 +1,344 @@
+/* -*- 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