286 lines
7.3 KiB
C
286 lines
7.3 KiB
C
/*
|
||
* tclPreserve.c --
|
||
*
|
||
* This file contains a collection of procedures that are used
|
||
* to make sure that widget records and other data structures
|
||
* aren't reallocated when there are nested procedures that
|
||
* depend on their existence.
|
||
*
|
||
* Copyright (c) 1991-1994 The Regents of the University of California.
|
||
* Copyright (c) 1994-1995 Sun Microsystems, Inc.
|
||
*
|
||
* See the file "license.terms" for information on usage and redistribution
|
||
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
|
||
*
|
||
* SCCS: @(#) tclPreserve.c 1.18 96/08/05 13:15:08
|
||
*/
|
||
|
||
#include "tclInt.h"
|
||
|
||
/*
|
||
* The following data structure is used to keep track of all the
|
||
* Tcl_Preserve calls that are still in effect. It grows as needed
|
||
* to accommodate any number of calls in effect.
|
||
*/
|
||
#if( defined(SCM_CODE) && \
|
||
!defined( Tcl_Preserve ) && \
|
||
!defined( Tcl_Release ) && \
|
||
!defined( Tcl_EventuallyFree ) )
|
||
|
||
typedef struct {
|
||
ClientData clientData; /* Address of preserved block. */
|
||
int refCount; /* Number of Tcl_Preserve calls in effect
|
||
* for block. */
|
||
int mustFree; /* Non-zero means Tcl_EventuallyFree was
|
||
* called while a Tcl_Preserve call was in
|
||
* effect, so the structure must be freed
|
||
* when refCount becomes zero. */
|
||
Tcl_FreeProc *freeProc; /* Procedure to call to free. */
|
||
} Reference;
|
||
|
||
static Reference *refArray; /* First in array of references. */
|
||
static int spaceAvl = 0; /* Total number of structures available
|
||
* at *firstRefPtr. */
|
||
static int inUse = 0; /* Count of structures currently in use
|
||
* in refArray. */
|
||
#define INITIAL_SIZE 2
|
||
|
||
/*
|
||
* Static routines in this file:
|
||
*/
|
||
|
||
static void PreserveExitProc _ANSI_ARGS_((ClientData clientData));
|
||
|
||
|
||
/*
|
||
*----------------------------------------------------------------------
|
||
*
|
||
* PreserveExitProc --
|
||
*
|
||
* Called during exit processing to clean up the reference array.
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side effects:
|
||
* Frees the storage of the reference array.
|
||
*
|
||
*----------------------------------------------------------------------
|
||
*/
|
||
|
||
/* ARGSUSED */
|
||
static void
|
||
PreserveExitProc(clientData)
|
||
ClientData clientData; /* NULL -Unused. */
|
||
{
|
||
if (spaceAvl != 0) {
|
||
ckfree((char *) refArray);
|
||
refArray = (Reference *) NULL;
|
||
inUse = 0;
|
||
spaceAvl = 0;
|
||
}
|
||
}
|
||
|
||
/*
|
||
*----------------------------------------------------------------------
|
||
*
|
||
* Tcl_Preserve --
|
||
*
|
||
* This procedure is used by a procedure to declare its interest
|
||
* in a particular block of memory, so that the block will not be
|
||
* reallocated until a matching call to Tcl_Release has been made.
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side effects:
|
||
* Information is retained so that the block of memory will
|
||
* not be freed until at least the matching call to Tcl_Release.
|
||
*
|
||
*----------------------------------------------------------------------
|
||
*/
|
||
void
|
||
Tcl_Preserve(clientData)
|
||
ClientData clientData; /* Pointer to malloc'ed block of memory. */
|
||
{
|
||
Reference *refPtr;
|
||
int i;
|
||
|
||
/*
|
||
* See if there is already a reference for this pointer. If so,
|
||
* just increment its reference count.
|
||
*/
|
||
|
||
for (i = 0, refPtr = refArray; i < inUse; i++, refPtr++) {
|
||
if (refPtr->clientData == clientData) {
|
||
refPtr->refCount++;
|
||
return;
|
||
}
|
||
}
|
||
|
||
/*
|
||
* Make a reference array if it doesn't already exist, or make it
|
||
* bigger if it is full.
|
||
*/
|
||
|
||
if (inUse == spaceAvl) {
|
||
if (spaceAvl == 0) {
|
||
Tcl_CreateExitHandler((Tcl_ExitProc *) PreserveExitProc,
|
||
(ClientData) NULL);
|
||
refArray = (Reference *) ckalloc((unsigned)
|
||
(INITIAL_SIZE*sizeof(Reference)));
|
||
spaceAvl = INITIAL_SIZE;
|
||
} else {
|
||
Reference *new;
|
||
|
||
new = (Reference *) ckalloc((unsigned)
|
||
(2*spaceAvl*sizeof(Reference)));
|
||
memcpy((VOID *) new, (VOID *) refArray,
|
||
spaceAvl*sizeof(Reference));
|
||
ckfree((char *) refArray);
|
||
refArray = new;
|
||
spaceAvl *= 2;
|
||
}
|
||
}
|
||
|
||
/*
|
||
* Make a new entry for the new reference.
|
||
*/
|
||
|
||
refPtr = &refArray[inUse];
|
||
refPtr->clientData = clientData;
|
||
refPtr->refCount = 1;
|
||
refPtr->mustFree = 0;
|
||
refPtr->freeProc = TCL_STATIC;
|
||
inUse += 1;
|
||
}
|
||
|
||
/*
|
||
*----------------------------------------------------------------------
|
||
*
|
||
* Tcl_Release --
|
||
*
|
||
* This procedure is called to cancel a previous call to
|
||
* Tcl_Preserve, thereby allowing a block of memory to be
|
||
* freed (if no one else cares about it).
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side effects:
|
||
* If Tcl_EventuallyFree has been called for clientData, and if
|
||
* no other call to Tcl_Preserve is still in effect, the block of
|
||
* memory is freed.
|
||
*
|
||
*----------------------------------------------------------------------
|
||
*/
|
||
|
||
void
|
||
Tcl_Release(clientData)
|
||
ClientData clientData; /* Pointer to malloc'ed block of memory. */
|
||
{
|
||
Reference *refPtr;
|
||
int mustFree;
|
||
Tcl_FreeProc *freeProc;
|
||
int i;
|
||
|
||
for (i = 0, refPtr = refArray; i < inUse; i++, refPtr++) {
|
||
if (refPtr->clientData != clientData) {
|
||
continue;
|
||
}
|
||
refPtr->refCount--;
|
||
if (refPtr->refCount == 0) {
|
||
|
||
/*
|
||
* Must remove information from the slot before calling freeProc
|
||
* to avoid reentrancy problems if the freeProc calls Tcl_Preserve
|
||
* on the same clientData. Copy down the last reference in the
|
||
* array to overwrite the current slot.
|
||
*/
|
||
|
||
freeProc = refPtr->freeProc;
|
||
mustFree = refPtr->mustFree;
|
||
inUse--;
|
||
if (i < inUse) {
|
||
refArray[i] = refArray[inUse];
|
||
}
|
||
if (mustFree) {
|
||
if ((freeProc == TCL_DYNAMIC) ||
|
||
(freeProc == (Tcl_FreeProc *) free)) {
|
||
ckfree((char *) clientData);
|
||
} else {
|
||
(*freeProc)((char *) clientData);
|
||
}
|
||
}
|
||
}
|
||
return;
|
||
}
|
||
|
||
/*
|
||
* Reference not found. This is a bug in the caller.
|
||
*/
|
||
|
||
panic("Tcl_Release couldn't find reference for 0x%x", clientData);
|
||
}
|
||
|
||
/*
|
||
*----------------------------------------------------------------------
|
||
*
|
||
* Tcl_EventuallyFree --
|
||
*
|
||
* Free up a block of memory, unless a call to Tcl_Preserve is in
|
||
* effect for that block. In this case, defer the free until all
|
||
* calls to Tcl_Preserve have been undone by matching calls to
|
||
* Tcl_Release.
|
||
*
|
||
* Results:
|
||
* None.
|
||
*
|
||
* Side effects:
|
||
* Ptr may be released by calling free().
|
||
*
|
||
*----------------------------------------------------------------------
|
||
*/
|
||
|
||
void
|
||
Tcl_EventuallyFree(clientData, freeProc)
|
||
ClientData clientData; /* Pointer to malloc'ed block of memory. */
|
||
Tcl_FreeProc *freeProc; /* Procedure to actually do free. */
|
||
{
|
||
Reference *refPtr;
|
||
int i;
|
||
|
||
/*
|
||
* See if there is a reference for this pointer. If so, set its
|
||
* "mustFree" flag (the flag had better not be set already!).
|
||
*/
|
||
|
||
for (i = 0, refPtr = refArray; i < inUse; i++, refPtr++) {
|
||
if (refPtr->clientData != clientData) {
|
||
continue;
|
||
}
|
||
if (refPtr->mustFree) {
|
||
panic("Tcl_EventuallyFree called twice for 0x%x\n", clientData);
|
||
}
|
||
refPtr->mustFree = 1;
|
||
refPtr->freeProc = freeProc;
|
||
return;
|
||
}
|
||
|
||
/*
|
||
* No reference for this block. Free it now.
|
||
*/
|
||
|
||
if ((freeProc == TCL_DYNAMIC)
|
||
#ifdef BGLK_CODE
|
||
|| (freeProc == (Tcl_FreeProc *) GC_free)) {
|
||
#else
|
||
|| (freeProc == (Tcl_FreeProc *) free)) {
|
||
#endif
|
||
ckfree((char *) clientData);
|
||
} else {
|
||
(*freeProc)((char *)clientData);
|
||
}
|
||
}
|
||
#endif
|