michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /*
michael@0: ** prcountr.c -- NSPR Instrumentation Counters
michael@0: **
michael@0: ** Implement the interface defined in prcountr.h
michael@0: **
michael@0: ** Design Notes:
michael@0: **
michael@0: ** The Counter Facility (CF) has a single anchor: qNameList.      
michael@0: ** The anchor is a PRCList. qNameList is a list of links in QName
michael@0: ** structures. From qNameList any QName structure and its
michael@0: ** associated RName structure can be located. 
michael@0: ** 
michael@0: ** For each QName, a list of RName structures is anchored at
michael@0: ** rnLink in the QName structure.
michael@0: ** 
michael@0: ** The counter itself is embedded in the RName structure.
michael@0: ** 
michael@0: ** For manipulating the counter database, single lock is used to
michael@0: ** protect the entire list: counterLock.
michael@0: **
michael@0: ** A PRCounterHandle, defined in prcountr.h, is really a pointer
michael@0: ** to a RName structure. References by PRCounterHandle are
michael@0: ** dead-reconed to the RName structure. The PRCounterHandle is
michael@0: ** "overloaded" for traversing the QName structures; only the
michael@0: ** function PR_FindNextQnameHandle() uses this overloading.
michael@0: **
michael@0: ** 
michael@0: ** ToDo (lth): decide on how to lock or atomically update
michael@0: ** individual counters. Candidates are: the global lock; a lock
michael@0: ** per RName structure; Atomic operations (Note that there are
michael@0: ** not adaquate atomic operations (yet) to achieve this goal). At
michael@0: ** this writing (6/19/98) , the update of the counter variable in
michael@0: ** a QName structure is unprotected.
michael@0: **
michael@0: */
michael@0: 
michael@0: #include "prcountr.h"
michael@0: #include "prclist.h"
michael@0: #include "prlock.h"
michael@0: #include "prlog.h"
michael@0: #include "prmem.h"
michael@0: #include <string.h>
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: typedef struct QName
michael@0: {
michael@0:     PRCList link;
michael@0:     PRCList rNameList;
michael@0:     char    name[PRCOUNTER_NAME_MAX+1];
michael@0: } QName;
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: typedef struct RName
michael@0: {
michael@0:     PRCList link;
michael@0:     QName   *qName;
michael@0:     PRLock  *lock;
michael@0:     volatile PRUint32   counter;    
michael@0:     char    name[PRCOUNTER_NAME_MAX+1]; 
michael@0:     char    desc[PRCOUNTER_DESC_MAX+1]; 
michael@0: } RName;
michael@0: 
michael@0: 
michael@0: /*
michael@0: ** Define the Counter Facility database
michael@0: */
michael@0: static PRLock  *counterLock;
michael@0: static PRCList qNameList;
michael@0: static PRLogModuleInfo *lm;
michael@0: 
michael@0: /*
michael@0: ** _PR_CounterInitialize() -- Initialize the Counter Facility
michael@0: **
michael@0: */
michael@0: static void _PR_CounterInitialize( void )
michael@0: {
michael@0:     /*
michael@0:     ** This function should be called only once
michael@0:     */
michael@0:     PR_ASSERT( counterLock == NULL );
michael@0:     
michael@0:     counterLock = PR_NewLock();
michael@0:     PR_INIT_CLIST( &qNameList );
michael@0:     lm = PR_NewLogModule("counters");
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: Initialization complete"));
michael@0: 
michael@0:     return;
michael@0: } /* end _PR_CounterInitialize() */
michael@0: 
michael@0: /*
michael@0: ** PR_CreateCounter() -- Create a counter
michael@0: **
michael@0: **  ValidateArguments
michael@0: **  Lock
michael@0: **  if (qName not already in database)
michael@0: **      NewQname
michael@0: **  if (rName already in database )
michael@0: **      Assert
michael@0: **  else NewRname
michael@0: **  NewCounter
michael@0: **  link 'em up
michael@0: **  Unlock
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(PRCounterHandle) 
michael@0: 	PR_CreateCounter( 
michael@0: 		const char *qName, 
michael@0:     	const char *rName, 
michael@0:         const char *description 
michael@0: ) 
michael@0: {
michael@0:     QName   *qnp;
michael@0:     RName   *rnp;
michael@0:     PRBool  matchQname = PR_FALSE;
michael@0: 
michael@0:     /* Self initialize, if necessary */
michael@0:     if ( counterLock == NULL )
michael@0:         _PR_CounterInitialize();
michael@0: 
michael@0:     /* Validate input arguments */
michael@0:     PR_ASSERT( strlen(qName) <= PRCOUNTER_NAME_MAX );
michael@0:     PR_ASSERT( strlen(rName) <= PRCOUNTER_NAME_MAX );
michael@0:     PR_ASSERT( strlen(description) <= PRCOUNTER_DESC_MAX );
michael@0: 
michael@0:     /* Lock the Facility */
michael@0:     PR_Lock( counterLock );
michael@0: 
michael@0:     /* Do we already have a matching QName? */
michael@0:     if (!PR_CLIST_IS_EMPTY( &qNameList ))
michael@0:     {
michael@0:         qnp = (QName *) PR_LIST_HEAD( &qNameList );
michael@0:         do {
michael@0:             if ( strcmp(qnp->name, qName) == 0)
michael@0:             {
michael@0:                 matchQname = PR_TRUE;
michael@0:                 break;
michael@0:             }
michael@0:             qnp = (QName *)PR_NEXT_LINK( &qnp->link );
michael@0:         } while( qnp != (QName *)&qNameList );
michael@0:     }
michael@0:     /*
michael@0:     ** If we did not find a matching QName,
michael@0:     **    allocate one and initialize it.
michael@0:     **    link it onto the qNameList.
michael@0:     **
michael@0:     */
michael@0:     if ( matchQname != PR_TRUE )
michael@0:     {
michael@0:         qnp = PR_NEWZAP( QName );
michael@0:         PR_ASSERT( qnp != NULL );
michael@0:         PR_INIT_CLIST( &qnp->link ); 
michael@0:         PR_INIT_CLIST( &qnp->rNameList ); 
michael@0:         strcpy( qnp->name, qName );
michael@0:         PR_APPEND_LINK( &qnp->link, &qNameList ); 
michael@0:     }
michael@0: 
michael@0:     /* Do we already have a matching RName? */
michael@0:     if (!PR_CLIST_IS_EMPTY( &qnp->rNameList ))
michael@0:     {
michael@0:         rnp = (RName *) PR_LIST_HEAD( &qnp->rNameList );
michael@0:         do {
michael@0:             /*
michael@0:             ** No duplicate RNames are allowed within a QName
michael@0:             **
michael@0:             */
michael@0:             PR_ASSERT( strcmp(rnp->name, rName));
michael@0:             rnp = (RName *)PR_NEXT_LINK( &rnp->link );
michael@0:         } while( rnp != (RName *)&qnp->rNameList );
michael@0:     }
michael@0: 
michael@0:     /* Get a new RName structure; initialize its members */
michael@0:     rnp = PR_NEWZAP( RName );
michael@0:     PR_ASSERT( rnp != NULL );
michael@0:     PR_INIT_CLIST( &rnp->link );
michael@0:     strcpy( rnp->name, rName );
michael@0:     strcpy( rnp->desc, description );
michael@0:     rnp->lock = PR_NewLock();
michael@0:     if ( rnp->lock == NULL )
michael@0:     {
michael@0:         PR_ASSERT(0);
michael@0:     }
michael@0: 
michael@0:     PR_APPEND_LINK( &rnp->link, &qnp->rNameList ); /* add RName to QName's rnList */    
michael@0:     rnp->qName = qnp;                       /* point the RName to the QName */
michael@0: 
michael@0:     /* Unlock the Facility */
michael@0:     PR_Unlock( counterLock );
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: Create: QName: %s %p, RName: %s %p\n\t",
michael@0:         qName, qnp, rName, rnp ));
michael@0: 
michael@0:     return((PRCounterHandle)rnp);
michael@0: } /*  end PR_CreateCounter() */
michael@0:   
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(void) 
michael@0: 	PR_DestroyCounter( 
michael@0: 		PRCounterHandle handle 
michael@0: )
michael@0: {
michael@0:     RName   *rnp = (RName *)handle;
michael@0:     QName   *qnp = rnp->qName;
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: Deleting: QName: %s, RName: %s", 
michael@0:         qnp->name, rnp->name));
michael@0: 
michael@0:     /* Lock the Facility */
michael@0:     PR_Lock( counterLock );
michael@0: 
michael@0:     /*
michael@0:     ** Remove RName from the list of RNames in QName
michael@0:     ** and free RName
michael@0:     */
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: Deleting RName: %s, %p", 
michael@0:         rnp->name, rnp));
michael@0:     PR_REMOVE_LINK( &rnp->link );
michael@0:     PR_Free( rnp->lock );
michael@0:     PR_DELETE( rnp );
michael@0: 
michael@0:     /*
michael@0:     ** If this is the last RName within QName
michael@0:     **   remove QName from the qNameList and free it
michael@0:     */
michael@0:     if ( PR_CLIST_IS_EMPTY( &qnp->rNameList ) )
michael@0:     {
michael@0:         PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: Deleting unused QName: %s, %p", 
michael@0:             qnp->name, qnp));
michael@0:         PR_REMOVE_LINK( &qnp->link );
michael@0:         PR_DELETE( qnp );
michael@0:     } 
michael@0: 
michael@0:     /* Unlock the Facility */
michael@0:     PR_Unlock( counterLock );
michael@0:     return;
michael@0: } /*  end PR_DestroyCounter() */
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(PRCounterHandle) 
michael@0: 	PR_GetCounterHandleFromName( 
michael@0:     	const char *qName, 
michael@0:     	const char *rName 
michael@0: )
michael@0: {
michael@0:     const char    *qn, *rn, *desc;
michael@0:     PRCounterHandle     qh, rh = NULL;
michael@0:     RName   *rnp = NULL;
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: GetCounterHandleFromName:\n\t"
michael@0:         "QName: %s, RName: %s", qName, rName ));
michael@0: 
michael@0:     qh = PR_FindNextCounterQname( NULL );
michael@0:     while (qh != NULL)
michael@0:     {
michael@0:         rh = PR_FindNextCounterRname( NULL, qh );
michael@0:         while ( rh != NULL )
michael@0:         {
michael@0:             PR_GetCounterNameFromHandle( rh, &qn, &rn, &desc );
michael@0:             if ( (strcmp( qName, qn ) == 0)
michael@0:                 && (strcmp( rName, rn ) == 0 ))
michael@0:             {
michael@0:                 rnp = (RName *)rh;
michael@0:                 goto foundIt;
michael@0:             }
michael@0:             rh = PR_FindNextCounterRname( rh, qh );
michael@0:         }
michael@0:         qh = PR_FindNextCounterQname( NULL );
michael@0:     }
michael@0: 
michael@0: foundIt:
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: GetConterHandleFromName: %p", rnp ));
michael@0:     return(rh);
michael@0: } /*  end PR_GetCounterHandleFromName() */
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(void) 
michael@0: 	PR_GetCounterNameFromHandle( 
michael@0:     	PRCounterHandle handle,  
michael@0: 	    const char **qName, 
michael@0: 	    const char **rName, 
michael@0: 		const char **description 
michael@0: )
michael@0: {
michael@0:     RName   *rnp = (RName *)handle;
michael@0:     QName   *qnp = rnp->qName;
michael@0: 
michael@0:     *qName = qnp->name;
michael@0:     *rName = rnp->name;
michael@0:     *description = rnp->desc;
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: GetConterNameFromHandle: "
michael@0:         "QNp: %p, RNp: %p,\n\tQName: %s, RName: %s, Desc: %s", 
michael@0:         qnp, rnp, qnp->name, rnp->name, rnp->desc ));
michael@0: 
michael@0:     return;
michael@0: } /*  end PR_GetCounterNameFromHandle() */
michael@0: 
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(void) 
michael@0: 	PR_IncrementCounter( 
michael@0: 		PRCounterHandle handle
michael@0: )
michael@0: {
michael@0:     PR_Lock(((RName *)handle)->lock);
michael@0:     ((RName *)handle)->counter++;
michael@0:     PR_Unlock(((RName *)handle)->lock);
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: Increment: %p, %ld", 
michael@0:         handle, ((RName *)handle)->counter ));
michael@0: 
michael@0:     return;
michael@0: } /*  end PR_IncrementCounter() */
michael@0: 
michael@0: 
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(void) 
michael@0: 	PR_DecrementCounter( 
michael@0: 		PRCounterHandle handle
michael@0: )
michael@0: {
michael@0:     PR_Lock(((RName *)handle)->lock);
michael@0:     ((RName *)handle)->counter--;
michael@0:     PR_Unlock(((RName *)handle)->lock);
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: Decrement: %p, %ld", 
michael@0:         handle, ((RName *)handle)->counter ));
michael@0: 
michael@0:     return;
michael@0: } /*  end PR_DecrementCounter()  */
michael@0: 
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(void) 
michael@0: 	PR_AddToCounter( 
michael@0:     	PRCounterHandle handle, 
michael@0: 	    PRUint32 value 
michael@0: )
michael@0: {
michael@0:     PR_Lock(((RName *)handle)->lock);
michael@0:     ((RName *)handle)->counter += value;
michael@0:     PR_Unlock(((RName *)handle)->lock);
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: AddToCounter: %p, %ld", 
michael@0:         handle, ((RName *)handle)->counter ));
michael@0: 
michael@0:     return;
michael@0: } /*  end PR_AddToCounter() */
michael@0: 
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(void) 
michael@0: 	PR_SubtractFromCounter( 
michael@0:     	PRCounterHandle handle, 
michael@0: 	    PRUint32 value 
michael@0: )
michael@0: {
michael@0:     PR_Lock(((RName *)handle)->lock);
michael@0:     ((RName *)handle)->counter -= value;
michael@0:     PR_Unlock(((RName *)handle)->lock);
michael@0:     
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: SubtractFromCounter: %p, %ld", 
michael@0:         handle, ((RName *)handle)->counter ));
michael@0: 
michael@0:     return;
michael@0: } /*  end  PR_SubtractFromCounter() */
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(PRUint32) 
michael@0: 	PR_GetCounter( 
michael@0: 		PRCounterHandle handle 
michael@0: )
michael@0: {
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: GetCounter: %p, %ld", 
michael@0:         handle, ((RName *)handle)->counter ));
michael@0: 
michael@0:     return(((RName *)handle)->counter);
michael@0: } /*  end  PR_GetCounter() */
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(void) 
michael@0: 	PR_SetCounter( 
michael@0: 		PRCounterHandle handle, 
michael@0: 		PRUint32 value 
michael@0: )
michael@0: {
michael@0:     ((RName *)handle)->counter = value;
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: SetCounter: %p, %ld", 
michael@0:         handle, ((RName *)handle)->counter ));
michael@0: 
michael@0:     return;
michael@0: } /*  end  PR_SetCounter() */
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(PRCounterHandle) 
michael@0: 	PR_FindNextCounterQname( 
michael@0:         PRCounterHandle handle
michael@0: )
michael@0: {
michael@0:     QName *qnp = (QName *)handle;
michael@0: 
michael@0:     if ( PR_CLIST_IS_EMPTY( &qNameList ))
michael@0:             qnp = NULL;
michael@0:     else if ( qnp == NULL )
michael@0:         qnp = (QName *)PR_LIST_HEAD( &qNameList );
michael@0:     else if ( PR_NEXT_LINK( &qnp->link ) ==  &qNameList )
michael@0:         qnp = NULL;
michael@0:     else  
michael@0:         qnp = (QName *)PR_NEXT_LINK( &qnp->link );
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: FindNextQname: Handle: %p, Returns: %p", 
michael@0:         handle, qnp ));
michael@0: 
michael@0:     return((PRCounterHandle)qnp);
michael@0: } /*  end  PR_FindNextCounterQname() */
michael@0: 
michael@0: 
michael@0: /*
michael@0: **
michael@0: */
michael@0: PR_IMPLEMENT(PRCounterHandle) 
michael@0: 	PR_FindNextCounterRname( 
michael@0:         PRCounterHandle rhandle, 
michael@0:         PRCounterHandle qhandle 
michael@0: )
michael@0: {
michael@0:     RName *rnp = (RName *)rhandle;
michael@0:     QName *qnp = (QName *)qhandle;
michael@0: 
michael@0: 
michael@0:     if ( PR_CLIST_IS_EMPTY( &qnp->rNameList ))
michael@0:         rnp = NULL;
michael@0:     else if ( rnp == NULL )
michael@0:         rnp = (RName *)PR_LIST_HEAD( &qnp->rNameList );
michael@0:     else if ( PR_NEXT_LINK( &rnp->link ) ==  &qnp->rNameList )
michael@0:         rnp = NULL;
michael@0:     else
michael@0:         rnp = (RName *)PR_NEXT_LINK( &rnp->link );
michael@0: 
michael@0:     PR_LOG( lm, PR_LOG_DEBUG, ("PR_Counter: FindNextRname: Rhandle: %p, QHandle: %p, Returns: %p", 
michael@0:         rhandle, qhandle, rnp ));
michael@0: 
michael@0:     return((PRCounterHandle)rnp);
michael@0: } /*  end PR_FindNextCounterRname() */