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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 prcountr_h___
+#define prcountr_h___
+
+/*----------------------------------------------------------------------------
+** prcountr.h -- NSPR Instrumentation counters
+**
+** The NSPR Counter Feature provides a means to "count
+** something." Counters can be dynamically defined, incremented,
+** decremented, set, and deleted under application program
+** control.
+**
+** The Counter Feature is intended to be used as instrumentation,
+** not as operational data. If you need a counter for operational
+** data, use native integral types.
+**
+** Counters are 32bit unsigned intergers. On overflow, a counter
+** will wrap. No exception is recognized or reported.
+**
+** A counter can be dynamically created using a two level naming
+** convention. A "handle" is returned when the counter is
+** created. The counter can subsequently be addressed by its
+** handle. An API is provided to get an existing counter's handle
+** given the names with which it was originally created.
+** Similarly, a counter's name can be retrieved given its handle.
+**
+** The counter naming convention is a two-level hierarchy. The
+** QName is the higher level of the hierarchy; RName is the
+** lower level. RNames can be thought of as existing within a
+** QName. The same RName can exist within multiple QNames. QNames
+** are unique. The NSPR Counter is not a near-zero overhead
+** feature. Application designers should be aware of
+** serialization issues when using the Counter API. Creating a
+** counter locks a large asset, potentially causing a stall. This
+** suggest that applications should create counters at component
+** initialization, for example, and not create and destroy them
+** willy-nilly. ... You have been warned.
+**
+** Incrementing and Adding to counters uses atomic operations.
+** The performance of these operations will vary from platform
+** to platform. On platforms where atomic operations are not
+** supported the overhead may be substantial.
+**
+** When traversing the counter database with FindNext functions,
+** the instantaneous values of any given counter is that at the
+** moment of extraction. The state of the entire counter database
+** may not be viewed as atomic.
+**
+** The counter interface may be disabled (No-Op'd) at compile
+** time. When DEBUG is defined at compile time, the Counter
+** Feature is compiled into NSPR and applications invoking it.
+** When DEBUG is not defined, the counter macros compile to
+** nothing. To force the Counter Feature to be compiled into an
+** optimized build, define FORCE_NSPR_COUNTERS at compile time
+** for both NSPR and the application intending to use it.
+**
+** Application designers should use the macro form of the Counter
+** Feature methods to minimize performance impact in optimized
+** builds. The macros normally compile to nothing on optimized
+** builds.
+**
+** Application designers should be aware of the effects of
+** debug and optimized build differences when using result of the
+** Counter Feature macros in expressions.
+**
+** The Counter Feature is thread-safe and SMP safe.
+**
+** /lth. 09-Jun-1998.
+*/
+
+#include "prtypes.h"
+
+PR_BEGIN_EXTERN_C
+
+/*
+** Opaque counter handle type.
+** ... don't even think of looking in here.
+**
+*/
+typedef void * PRCounterHandle;
+
+#define PRCOUNTER_NAME_MAX 31
+#define PRCOUNTER_DESC_MAX 255
+
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_DEFINE_COUNTER() -- Define a PRCounterHandle
+**
+** DESCRIPTION: PR_DEFINE_COUNTER() is used to define a counter
+** handle.
+**
+*/
+#define PR_DEFINE_COUNTER(name) PRCounterHandle name
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_INIT_COUNTER_HANDLE() -- Set the value of a PRCounterHandle
+**
+** DESCRIPTION:
+** PR_INIT_COUNTER_HANDLE() sets the value of a PRCounterHandle
+** to value.
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_INIT_COUNTER_HANDLE(handle,value)\
+ (handle) = (PRCounterHandle)(value)
+#else
+#define PR_INIT_COUNTER_HANDLE(handle,value)
+#endif
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_CreateCounter() -- Create a counter
+**
+** DESCRIPTION: PR_CreateCounter() creates a counter object and
+** initializes it to zero.
+**
+** The macro form takes as its first argument the name of the
+** PRCounterHandle to receive the handle returned from
+** PR_CreateCounter().
+**
+** INPUTS:
+** qName: The QName for the counter object. The maximum length
+** of qName is defined by PRCOUNTER_NAME_MAX
+**
+** rName: The RName for the counter object. The maximum length
+** of qName is defined by PRCOUNTER_NAME_MAX
+**
+** descrioption: The description of the counter object. The
+** maximum length of description is defined by
+** PRCOUNTER_DESC_MAX.
+**
+** OUTPUTS:
+**
+** RETURNS:
+** PRCounterHandle.
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_CREATE_COUNTER(handle,qName,rName,description)\
+ (handle) = PR_CreateCounter((qName),(rName),(description))
+#else
+#define PR_CREATE_COUNTER(handle,qName,rName,description)
+#endif
+
+NSPR_API(PRCounterHandle)
+PR_CreateCounter(
+ const char *qName,
+ const char *rName,
+ const char *description
+);
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_DestroyCounter() -- Destroy a counter object.
+**
+** DESCRIPTION: PR_DestroyCounter() removes a counter and
+** unregisters its handle from the counter database.
+**
+** INPUTS:
+** handle: the PRCounterHandle of the counter to be destroyed.
+**
+** OUTPUTS:
+** The counter is destroyed.
+**
+** RETURNS: void
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_DESTROY_COUNTER(handle) PR_DestroyCounter((handle))
+#else
+#define PR_DESTROY_COUNTER(handle)
+#endif
+
+NSPR_API(void)
+PR_DestroyCounter(
+ PRCounterHandle handle
+);
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_GetCounterHandleFromName() -- Retreive a
+** counter's handle give its name.
+**
+** DESCRIPTION: PR_GetCounterHandleFromName() retreives a
+** counter's handle from the counter database, given the name
+** the counter was originally created with.
+**
+** INPUTS:
+** qName: Counter's original QName.
+** rName: Counter's original RName.
+**
+** OUTPUTS:
+**
+** RETURNS:
+** PRCounterHandle or PRCounterError.
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_GET_COUNTER_HANDLE_FROM_NAME(handle,qName,rName)\
+ (handle) = PR_GetCounterHandleFromName((qName),(rName))
+#else
+#define PR_GET_COUNTER_HANDLE_FROM_NAME(handle,qName,rName)
+#endif
+
+NSPR_API(PRCounterHandle)
+PR_GetCounterHandleFromName(
+ const char *qName,
+ const char *rName
+);
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_GetCounterNameFromHandle() -- Retreive a
+** counter's name, given its handle.
+**
+** DESCRIPTION: PR_GetCounterNameFromHandle() retreives a
+** counter's name given its handle.
+**
+** INPUTS:
+** qName: Where to store a pointer to qName.
+** rName: Where to store a pointer to rName.
+** description: Where to store a pointer to description.
+**
+** OUTPUTS: Pointers to the Counter Feature's copies of the names
+** used when the counters were created.
+**
+** RETURNS: void
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_GET_COUNTER_NAME_FROM_HANDLE(handle,qName,rName,description)\
+ PR_GetCounterNameFromHandle((handle),(qName),(rName),(description))
+#else
+#define PR_GET_COUNTER_NAME_FROM_HANDLE(handle,qName,rName,description )
+#endif
+
+NSPR_API(void)
+PR_GetCounterNameFromHandle(
+ PRCounterHandle handle,
+ const char **qName,
+ const char **rName,
+ const char **description
+);
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_IncrementCounter() -- Add one to the referenced
+** counter.
+**
+** DESCRIPTION: Add one to the referenced counter.
+**
+** INPUTS:
+** handle: The PRCounterHandle of the counter to be incremented
+**
+** OUTPUTS: The counter is incrementd.
+**
+** RETURNS: void
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_INCREMENT_COUNTER(handle) PR_IncrementCounter(handle)
+#else
+#define PR_INCREMENT_COUNTER(handle)
+#endif
+
+NSPR_API(void)
+PR_IncrementCounter(
+ PRCounterHandle handle
+);
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_DecrementCounter() -- Subtract one from the
+** referenced counter
+**
+** DESCRIPTION: Subtract one from the referenced counter.
+**
+** INPUTS:
+** handle: The PRCounterHandle of the coutner to be
+** decremented.
+**
+** OUTPUTS: the counter is decremented.
+**
+** RETURNS: void
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_DECREMENT_COUNTER(handle) PR_DecrementCounter(handle)
+#else
+#define PR_DECREMENT_COUNTER(handle)
+#endif
+
+NSPR_API(void)
+PR_DecrementCounter(
+ PRCounterHandle handle
+);
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_AddToCounter() -- Add a value to a counter.
+**
+** DESCRIPTION: Add value to the counter referenced by handle.
+**
+** INPUTS:
+** handle: the PRCounterHandle of the counter to be added to.
+**
+** value: the value to be added to the counter.
+**
+** OUTPUTS: new value for counter.
+**
+** RETURNS: void
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_ADD_TO_COUNTER(handle,value)\
+ PR_AddToCounter((handle),(value))
+#else
+#define PR_ADD_TO_COUNTER(handle,value)
+#endif
+
+NSPR_API(void)
+PR_AddToCounter(
+ PRCounterHandle handle,
+ PRUint32 value
+);
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_SubtractFromCounter() -- A value is subtracted
+** from a counter.
+**
+** DESCRIPTION:
+** Subtract a value from a counter.
+**
+** INPUTS:
+** handle: the PRCounterHandle of the counter to be subtracted
+** from.
+**
+** value: the value to be subtracted from the counter.
+**
+** OUTPUTS: new value for counter
+**
+** RETURNS: void
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_SUBTRACT_FROM_COUNTER(handle,value)\
+ PR_SubtractFromCounter((handle),(value))
+#else
+#define PR_SUBTRACT_FROM_COUNTER(handle,value)
+#endif
+
+NSPR_API(void)
+PR_SubtractFromCounter(
+ PRCounterHandle handle,
+ PRUint32 value
+);
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_GetCounter() -- Retreive the value of a counter
+**
+** DESCRIPTION:
+** Retreive the value of a counter.
+**
+** INPUTS:
+** handle: the PR_CounterHandle of the counter to be retreived
+**
+** OUTPUTS:
+**
+** RETURNS: The value of the referenced counter
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_GET_COUNTER(counter,handle)\
+ (counter) = PR_GetCounter((handle))
+#else
+#define PR_GET_COUNTER(counter,handle) 0
+#endif
+
+NSPR_API(PRUint32)
+PR_GetCounter(
+ PRCounterHandle handle
+);
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_SetCounter() -- Replace the content of counter
+** with value.
+**
+** DESCRIPTION: The contents of the referenced counter are
+** replaced by value.
+**
+** INPUTS:
+** handle: the PRCounterHandle of the counter whose contents
+** are to be replaced.
+**
+** value: the new value of the counter.
+**
+** OUTPUTS:
+**
+** RETURNS: void
+**
+** RESTRICTIONS:
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_SET_COUNTER(handle,value) PR_SetCounter((handle),(value))
+#else
+#define PR_SET_COUNTER(handle,value)
+#endif
+
+NSPR_API(void)
+PR_SetCounter(
+ PRCounterHandle handle,
+ PRUint32 value
+);
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_FindNextCounterQname() -- Retreive the next QName counter
+** handle iterator
+**
+** DESCRIPTION:
+** PR_FindNextCounterQname() retreives the first or next Qname
+** the counter data base, depending on the value of handle. When
+** handle is NULL, the function attempts to retreive the first
+** QName handle in the database. When handle is a handle previosly
+** retreived QName handle, then the function attempts to retreive
+** the next QName handle.
+**
+** INPUTS:
+** handle: PRCounterHandle or NULL.
+**
+** OUTPUTS: returned
+**
+** RETURNS: PRCounterHandle or NULL when no more QName counter
+** handles are present.
+**
+** RESTRICTIONS:
+** A concurrent PR_CreateCounter() or PR_DestroyCounter() may
+** cause unpredictable results.
+**
+** A PRCounterHandle returned from this function may only be used
+** in another PR_FindNextCounterQname() function call; other
+** operations may cause unpredictable results.
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_FIND_NEXT_COUNTER_QNAME(next,handle)\
+ (next) = PR_FindNextCounterQname((handle))
+#else
+#define PR_FIND_NEXT_COUNTER_QNAME(next,handle) NULL
+#endif
+
+NSPR_API(PRCounterHandle)
+PR_FindNextCounterQname(
+ PRCounterHandle handle
+);
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PR_FindNextCounterRname() -- Retreive the next RName counter
+** handle iterator
+**
+** DESCRIPTION:
+** PR_FindNextCounterRname() retreives the first or next RNname
+** handle from the counter data base, depending on the
+** value of handle. When handle is NULL, the function attempts to
+** retreive the first RName handle in the database. When handle is
+** a handle previosly retreived RName handle, then the function
+** attempts to retreive the next RName handle.
+**
+** INPUTS:
+** handle: PRCounterHandle or NULL.
+** qhandle: PRCounterHandle of a previously aquired via
+** PR_FIND_NEXT_QNAME_HANDLE()
+**
+** OUTPUTS: returned
+**
+** RETURNS: PRCounterHandle or NULL when no more RName counter
+** handles are present.
+**
+** RESTRICTIONS:
+** A concurrent PR_CreateCounter() or PR_DestroyCounter() may
+** cause unpredictable results.
+**
+** A PRCounterHandle returned from this function may only be used
+** in another PR_FindNextCounterRname() function call; other
+** operations may cause unpredictable results.
+**
+*/
+#if defined(DEBUG) || defined(FORCE_NSPR_COUNTERS)
+#define PR_FIND_NEXT_COUNTER_RNAME(next,rhandle,qhandle)\
+ (next) = PR_FindNextCounterRname((rhandle),(qhandle))
+#else
+#define PR_FIND_NEXT_COUNTER_RNAME(next,rhandle,qhandle)
+#endif
+
+NSPR_API(PRCounterHandle)
+PR_FindNextCounterRname(
+ PRCounterHandle rhandle,
+ PRCounterHandle qhandle
+);
+
+PR_END_EXTERN_C
+
+#endif /* prcountr_h___ */