/* -*- 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___ */