| 1 | /*
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| 2 | * tclPreserve.c --
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| 3 | *
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| 4 | * This file contains a collection of procedures that are used
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| 5 | * to make sure that widget records and other data structures
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| 6 | * aren't reallocated when there are nested procedures that
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| 7 | * depend on their existence.
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| 8 | *
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| 9 | * Copyright (c) 1991-1994 The Regents of the University of California.
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| 10 | * Copyright (c) 1994-1995 Sun Microsystems, Inc.
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| 11 | *
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| 12 | * See the file "license.terms" for information on usage and redistribution
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| 13 | * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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| 14 | *
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| 15 | * RCS: @(#) $Id: tclPreserve.c,v 1.1 2008-06-04 13:58:10 demin Exp $
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| 16 | */
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| 17 |
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| 18 | #include "tclInt.h"
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| 19 |
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| 20 | /*
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| 21 | * The following data structure is used to keep track of all the
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| 22 | * Tcl_Preserve calls that are still in effect. It grows as needed
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| 23 | * to accommodate any number of calls in effect.
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| 24 | */
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| 25 |
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| 26 | typedef struct {
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| 27 | ClientData clientData; /* Address of preserved block. */
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| 28 | int refCount; /* Number of Tcl_Preserve calls in effect
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| 29 | * for block. */
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| 30 | int mustFree; /* Non-zero means Tcl_EventuallyFree was
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| 31 | * called while a Tcl_Preserve call was in
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| 32 | * effect, so the structure must be freed
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| 33 | * when refCount becomes zero. */
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| 34 | Tcl_FreeProc *freeProc; /* Procedure to call to free. */
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| 35 | } Reference;
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| 36 |
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| 37 | static Reference *refArray; /* First in array of references. */
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| 38 | static int inUse = 0; /* Count of structures currently in use
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| 39 | * in refArray. */
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| 40 | #define INITIAL_SIZE 2
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| 41 |
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| 42 | /*
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| 43 | *----------------------------------------------------------------------
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| 44 | *
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| 45 | * Tcl_EventuallyFree --
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| 46 | *
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| 47 | * Free up a block of memory, unless a call to Tcl_Preserve is in
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| 48 | * effect for that block. In this case, defer the free until all
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| 49 | * calls to Tcl_Preserve have been undone by matching calls to
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| 50 | * Tcl_Release.
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| 51 | *
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| 52 | * Results:
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| 53 | * None.
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| 54 | *
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| 55 | * Side effects:
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| 56 | * Ptr may be released by calling free().
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| 57 | *
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| 58 | *----------------------------------------------------------------------
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| 59 | */
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| 60 |
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| 61 | void
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| 62 | Tcl_EventuallyFree(clientData, freeProc)
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| 63 | ClientData clientData; /* Pointer to malloc'ed block of memory. */
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| 64 | Tcl_FreeProc *freeProc; /* Procedure to actually do free. */
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| 65 | {
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| 66 | Reference *refPtr;
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| 67 | int i;
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| 68 |
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| 69 | /*
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| 70 | * See if there is a reference for this pointer. If so, set its
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| 71 | * "mustFree" flag (the flag had better not be set already!).
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| 72 | */
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| 73 |
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| 74 | for (i = 0, refPtr = refArray; i < inUse; i++, refPtr++) {
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| 75 | if (refPtr->clientData != clientData) {
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| 76 | continue;
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| 77 | }
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| 78 | if (refPtr->mustFree) {
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| 79 | panic("Tcl_EventuallyFree called twice for 0x%x\n", clientData);
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| 80 | }
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| 81 | refPtr->mustFree = 1;
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| 82 | refPtr->freeProc = freeProc;
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| 83 | return;
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| 84 | }
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| 85 |
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| 86 | /*
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| 87 | * No reference for this block. Free it now.
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| 88 | */
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| 89 |
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| 90 | if ((freeProc == TCL_DYNAMIC)
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| 91 | || (freeProc == (Tcl_FreeProc *) free)) {
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| 92 | ckfree((char *) clientData);
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| 93 | } else {
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| 94 | (*freeProc)((char *)clientData);
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| 95 | }
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| 96 | }
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