tclobj.c

tcl是工具命令语言

/* 
 * tclObj.c --
 *
 *	This file contains Tcl object-related procedures that are used by
 * 	many Tcl commands.
 *
 * Copyright (c) 1995-1997 Sun Microsystems, Inc.
 * Copyright (c) 1999 by Scriptics Corporation.
 * Copyright (c) 2001 by ActiveState Corporation.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclObj.c,v 1.42 2003/01/17 22:11:02 mdejong Exp $
 */

#include "tclInt.h"
#include "tclCompile.h"
#include "tclPort.h"

/*
 * Table of all object types.
 */

static Tcl_HashTable typeTable;
static int typeTableInitialized = 0;    /* 0 means not yet initialized. */
TCL_DECLARE_MUTEX(tableMutex)

/*
 * Head of the list of free Tcl_Obj structs we maintain.
 */

Tcl_Obj *tclFreeObjList = NULL;

/*
 * The object allocator is single threaded.  This mutex is referenced
 * by the TclNewObj macro, however, so must be visible.
 */

#ifdef TCL_THREADS
Tcl_Mutex tclObjMutex;
#endif

/*
 * Pointer to a heap-allocated string of length zero that the Tcl core uses
 * as the value of an empty string representation for an object. This value
 * is shared by all new objects allocated by Tcl_NewObj.
 */

char tclEmptyString = '\0';
char *tclEmptyStringRep = &tclEmptyString;

/*
 * Prototypes for procedures defined later in this file:
 */

static int		SetBooleanFromAny _ANSI_ARGS_((Tcl_Interp *interp,
			    Tcl_Obj *objPtr));
static int		SetDoubleFromAny _ANSI_ARGS_((Tcl_Interp *interp,
			    Tcl_Obj *objPtr));
static int		SetIntFromAny _ANSI_ARGS_((Tcl_Interp *interp,
			    Tcl_Obj *objPtr));
static void		UpdateStringOfBoolean _ANSI_ARGS_((Tcl_Obj *objPtr));
static void		UpdateStringOfDouble _ANSI_ARGS_((Tcl_Obj *objPtr));
static void		UpdateStringOfInt _ANSI_ARGS_((Tcl_Obj *objPtr));
#ifndef TCL_WIDE_INT_IS_LONG
static int		SetWideIntFromAny _ANSI_ARGS_((Tcl_Interp *interp,
			    Tcl_Obj *objPtr));
static void		UpdateStringOfWideInt _ANSI_ARGS_((Tcl_Obj *objPtr));
#endif

/*
 * Prototypes for the array hash key methods.
 */

static Tcl_HashEntry *	AllocObjEntry _ANSI_ARGS_((
			    Tcl_HashTable *tablePtr, VOID *keyPtr));
static int		CompareObjKeys _ANSI_ARGS_((
			    VOID *keyPtr, Tcl_HashEntry *hPtr));
static void		FreeObjEntry _ANSI_ARGS_((
			    Tcl_HashEntry *hPtr));
static unsigned int	HashObjKey _ANSI_ARGS_((
			    Tcl_HashTable *tablePtr,
			    VOID *keyPtr));

/*
 * Prototypes for the CommandName object type.
 */

static void		DupCmdNameInternalRep _ANSI_ARGS_((Tcl_Obj *objPtr,
			    Tcl_Obj *copyPtr));
static void		FreeCmdNameInternalRep _ANSI_ARGS_((
    			    Tcl_Obj *objPtr));
static int		SetCmdNameFromAny _ANSI_ARGS_((Tcl_Interp *interp,
			    Tcl_Obj *objPtr));


/*
 * The structures below defines the Tcl object types defined in this file by
 * means of procedures that can be invoked by generic object code. See also
 * tclStringObj.c, tclListObj.c, tclByteCode.c for other type manager
 * implementations.
 */

Tcl_ObjType tclBooleanType = {
    "boolean",				/* name */
    (Tcl_FreeInternalRepProc *) NULL,   /* freeIntRepProc */
    (Tcl_DupInternalRepProc *) NULL,	/* dupIntRepProc */
    UpdateStringOfBoolean,		/* updateStringProc */
    SetBooleanFromAny			/* setFromAnyProc */
};

Tcl_ObjType tclDoubleType = {
    "double",				/* name */
    (Tcl_FreeInternalRepProc *) NULL,   /* freeIntRepProc */
    (Tcl_DupInternalRepProc *) NULL,	/* dupIntRepProc */
    UpdateStringOfDouble,		/* updateStringProc */
    SetDoubleFromAny			/* setFromAnyProc */
};

Tcl_ObjType tclIntType = {
    "int",				/* name */
    (Tcl_FreeInternalRepProc *) NULL,   /* freeIntRepProc */
    (Tcl_DupInternalRepProc *) NULL,	/* dupIntRepProc */
    UpdateStringOfInt,			/* updateStringProc */
    SetIntFromAny			/* setFromAnyProc */
};

#ifndef TCL_WIDE_INT_IS_LONG
Tcl_ObjType tclWideIntType = {
    "wideInt",				/* name */
    (Tcl_FreeInternalRepProc *) NULL,   /* freeIntRepProc */
    (Tcl_DupInternalRepProc *) NULL,	/* dupIntRepProc */
    UpdateStringOfWideInt,		/* updateStringProc */
    SetWideIntFromAny			/* setFromAnyProc */
};
#endif

/*
 * The structure below defines the Tcl obj hash key type.
 */
Tcl_HashKeyType tclObjHashKeyType = {
    TCL_HASH_KEY_TYPE_VERSION,		/* version */
    0,					/* flags */
    HashObjKey,				/* hashKeyProc */
    CompareObjKeys,			/* compareKeysProc */
    AllocObjEntry,			/* allocEntryProc */
    FreeObjEntry			/* freeEntryProc */
};

/*
 * The structure below defines the command name Tcl object type by means of
 * procedures that can be invoked by generic object code. Objects of this
 * type cache the Command pointer that results from looking up command names
 * in the command hashtable. Such objects appear as the zeroth ("command
 * name") argument in a Tcl command.
 */

static Tcl_ObjType tclCmdNameType = {
    "cmdName",				/* name */
    FreeCmdNameInternalRep,		/* freeIntRepProc */
    DupCmdNameInternalRep,		/* dupIntRepProc */
    (Tcl_UpdateStringProc *) NULL,	/* updateStringProc */
    SetCmdNameFromAny			/* setFromAnyProc */
};


/*
 * Structure containing a cached pointer to a command that is the result
 * of resolving the command's name in some namespace. It is the internal
 * representation for a cmdName object. It contains the pointer along
 * with some information that is used to check the pointer's validity.
 */

typedef struct ResolvedCmdName {
    Command *cmdPtr;		/* A cached Command pointer. */
    Namespace *refNsPtr;	/* Points to the namespace containing the
				 * reference (not the namespace that
				 * contains the referenced command). */
    long refNsId;		/* refNsPtr's unique namespace id. Used to
				 * verify that refNsPtr is still valid
				 * (e.g., it's possible that the cmd's
				 * containing namespace was deleted and a
				 * new one created at the same address). */
    int refNsCmdEpoch;		/* Value of the referencing namespace's
				 * cmdRefEpoch when the pointer was cached.
				 * Before using the cached pointer, we check
				 * if the namespace's epoch was incremented;
				 * if so, this cached pointer is invalid. */
    int cmdEpoch;		/* Value of the command's cmdEpoch when this
				 * pointer was cached. Before using the
				 * cached pointer, we check if the cmd's
				 * epoch was incremented; if so, the cmd was
				 * renamed, deleted, hidden, or exposed, and
				 * so the pointer is invalid. */
    int refCount;		/* Reference count: 1 for each cmdName
				 * object that has a pointer to this
				 * ResolvedCmdName structure as its internal
				 * rep. This structure can be freed when
				 * refCount becomes zero. */
} ResolvedCmdName;


/*
 *-------------------------------------------------------------------------
 *
 * TclInitObjectSubsystem --
 *
 *	This procedure is invoked to perform once-only initialization of
 *	the type table. It also registers the object types defined in 
 *	this file.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Initializes the table of defined object types "typeTable" with
 *	builtin object types defined in this file.  
 *
 *-------------------------------------------------------------------------
 */

void
TclInitObjSubsystem()
{
    Tcl_MutexLock(&tableMutex);
    typeTableInitialized = 1;
    Tcl_InitHashTable(&typeTable, TCL_STRING_KEYS);
    Tcl_MutexUnlock(&tableMutex);

    Tcl_RegisterObjType(&tclBooleanType);
    Tcl_RegisterObjType(&tclByteArrayType);
    Tcl_RegisterObjType(&tclDoubleType);
    Tcl_RegisterObjType(&tclEndOffsetType);
    Tcl_RegisterObjType(&tclIntType);
#ifndef TCL_WIDE_INT_IS_LONG
    Tcl_RegisterObjType(&tclWideIntType);
#endif
    Tcl_RegisterObjType(&tclStringType);
    Tcl_RegisterObjType(&tclListType);
    Tcl_RegisterObjType(&tclByteCodeType);
    Tcl_RegisterObjType(&tclProcBodyType);
    Tcl_RegisterObjType(&tclArraySearchType);
    Tcl_RegisterObjType(&tclIndexType);
    Tcl_RegisterObjType(&tclNsNameType);
    Tcl_RegisterObjType(&tclCmdNameType);

#ifdef TCL_COMPILE_STATS
    Tcl_MutexLock(&tclObjMutex);
    tclObjsAlloced = 0;
    tclObjsFreed = 0;
    {
	int i;
	for (i = 0;  i < TCL_MAX_SHARED_OBJ_STATS;  i++) {
	    tclObjsShared[i] = 0;
	}
    }
    Tcl_MutexUnlock(&tclObjMutex);
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * TclFinalizeCompExecEnv --
 *
 *	This procedure is called by Tcl_Finalize to clean up the Tcl
 *	compilation and execution environment so it can later be properly
 *	reinitialized.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Cleans up the compilation and execution environment
 *
 *----------------------------------------------------------------------
 */

void
TclFinalizeCompExecEnv()
{
    Tcl_MutexLock(&tableMutex);
    if (typeTableInitialized) {
        Tcl_DeleteHashTable(&typeTable);
        typeTableInitialized = 0;
    }
    Tcl_MutexUnlock(&tableMutex);
    Tcl_MutexLock(&tclObjMutex);
    tclFreeObjList = NULL;
    Tcl_MutexUnlock(&tclObjMutex);

    TclFinalizeCompilation();
    TclFinalizeExecution();
}

/*
 *--------------------------------------------------------------
 *
 * Tcl_RegisterObjType --
 *
 *	This procedure is called to register a new Tcl object type
 *	in the table of all object types supported by Tcl.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The type is registered in the Tcl type table. If there was already
 *	a type with the same name as in typePtr, it is replaced with the
 *	new type.
 *
 *--------------------------------------------------------------
 */

void
Tcl_RegisterObjType(typePtr)
    Tcl_ObjType *typePtr;	/* Information about object type;
				 * storage must be statically
				 * allocated (must live forever). */
{
    register Tcl_HashEntry *hPtr;
    int new;

    /*
     * If there's already an object type with the given name, remove it.
     */
    Tcl_MutexLock(&tableMutex);
    hPtr = Tcl_FindHashEntry(&typeTable, typePtr->name);
    if (hPtr != (Tcl_HashEntry *) NULL) {
        Tcl_DeleteHashEntry(hPtr);
    }

    /*
     * Now insert the new object type.
     */

    hPtr = Tcl_CreateHashEntry(&typeTable, typePtr->name, &new);
    if (new) {
	Tcl_SetHashValue(hPtr, typePtr);
    }
    Tcl_MutexUnlock(&tableMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AppendAllObjTypes --
 *
 *	This procedure appends onto the argument object the name of each
 *	object type as a list element. This includes the builtin object
 *	types (e.g. int, list) as well as those added using
 *	Tcl_NewObj. These names can be used, for example, with
 *	Tcl_GetObjType to get pointers to the corresponding Tcl_ObjType
 *	structures.
 *
 * Results:
 *	The return value is normally TCL_OK; in this case the object
 *	referenced by objPtr has each type name appended to it. If an
 *	error occurs, TCL_ERROR is returned and the interpreter's result
 *	holds an error message.
 *
 * Side effects:
 *	If necessary, the object referenced by objPtr is converted into
 *	a list object.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_AppendAllObjTypes(interp, objPtr)
    Tcl_Interp *interp;		/* Interpreter used for error reporting. */
    Tcl_Obj *objPtr;		/* Points to the Tcl object onto which the
				 * name of each registered type is appended
				 * as a list element. */
{
    register Tcl_HashEntry *hPtr;
    Tcl_HashSearch search;
    Tcl_ObjType *typePtr;
    int result;
 
    /*
     * This code assumes that types names do not contain embedded NULLs.
     */

    Tcl_MutexLock(&tableMutex);
    for (hPtr = Tcl_FirstHashEntry(&typeTable, &search);
	    hPtr != NULL;  hPtr = Tcl_NextHashEntry(&search)) {
        typePtr = (Tcl_ObjType *) Tcl_GetHashValue(hPtr);
	result = Tcl_ListObjAppendElement(interp, objPtr,
	        Tcl_NewStringObj(typePtr->name, -1));
	if (result == TCL_ERROR) {
	    Tcl_MutexUnlock(&tableMutex);
	    return result;
	}
    }
    Tcl_MutexUnlock(&tableMutex);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetObjType --
 *
 *	This procedure looks up an object type by name.
 *
 * Results:
 *	If an object type with name matching "typeName" is found, a pointer
 *	to its Tcl_ObjType structure is returned; otherwise, NULL is
 *	returned.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

Tcl_ObjType *
Tcl_GetObjType(typeName)
    CONST char *typeName;	/* Name of Tcl object type to look up. */
{
    register Tcl_HashEntry *hPtr;
    Tcl_ObjType *typePtr;

    Tcl_MutexLock(&tableMutex);
    hPtr = Tcl_FindHashEntry(&typeTable, typeName);
    if (hPtr != (Tcl_HashEntry *) NULL) {
        typePtr = (Tcl_ObjType *) Tcl_GetHashValue(hPtr);
	Tcl_MutexUnlock(&tableMutex);
	return typePtr;
    }
    Tcl_MutexUnlock(&tableMutex);
    return NULL;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ConvertToType --
 *
 *	Convert the Tcl object "objPtr" to have type "typePtr" if possible.
 *
 * Results:
 *	The return value is TCL_OK on success and TCL_ERROR on failure. If
 *	TCL_ERROR is returned, then the interpreter's result contains an
 *	error message unless "interp" is NULL. Passing a NULL "interp"
 *	allows this procedure to be used as a test whether the conversion
 *	could be done (and in fact was done).
 *
 * Side effects:
 *	Any internal representation for the old type is freed.
 *