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-rw-r--r--generic/tclDictObj.c63
1 files changed, 45 insertions, 18 deletions
diff --git a/generic/tclDictObj.c b/generic/tclDictObj.c
index 5d9fb9a..8755d4e 100644
--- a/generic/tclDictObj.c
+++ b/generic/tclDictObj.c
@@ -9,12 +9,30 @@
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tclDictObj.c,v 1.13 2004/01/14 09:34:33 dkf Exp $
+ * RCS: @(#) $Id: tclDictObj.c,v 1.14 2004/01/14 22:07:43 dkf Exp $
*/
#include "tclInt.h"
/*
+ * Flag values for TraceDictPath().
+ *
+ * DICT_PATH_UPDATE indicates that we are going to be doing an update
+ * at the tip of the path, so duplication of shared objects should be
+ * done along the way.
+ *
+ * DICT_PATH_EXISTS indicates that we are performing an existance test
+ * and a lookup failure should therefore not be an error. If (and
+ * only if) this flag is set, TraceDictPath() will return the special
+ * value DICT_PATH_NON_EXISTENT if the path is not traceable.
+ */
+
+#define DICT_PATH_UPDATE 1
+#define DICT_PATH_EXISTS 2
+
+#define DICT_PATH_NON_EXISTENT ((Tcl_Obj *) (void *) 1)
+
+/*
* Prototypes for procedures defined later in this file:
*/
@@ -58,7 +76,7 @@ static int SetDictFromAny _ANSI_ARGS_((Tcl_Interp *interp,
static void UpdateStringOfDict _ANSI_ARGS_((Tcl_Obj *dictPtr));
static Tcl_Obj * TraceDictPath _ANSI_ARGS_((Tcl_Interp *interp,
Tcl_Obj *rootPtr, int keyc, Tcl_Obj *CONST keyv[],
- int willUpdate));
+ int flags));
struct Dict;
static void DeleteDict _ANSI_ARGS_((struct Dict *dict));
@@ -545,25 +563,27 @@ SetDictFromAny(interp, objPtr)
* Results:
* The object at the end of the path, or NULL if there was an error.
* Note that this it is an error for an intermediate dictionary on
- * the path to not exist.
+ * the path to not exist. If the flags argument is DICT_PATH_EXISTS,
+ * a non-existent path gives a DICT_PATH_NON_EXISTENT result.
*
* Side effects:
- * If the willUpdate flag is false, there are no side effects (other
- * than potential conversion of objects to dictionaries.) If the
- * willUpdate flag is true, the following additional side effects
- * occur. Shared dictionaries along the path are converted into
- * unshared objects, and a backward-pointing chain is built using
- * the chain fields of the dictionaries (for easy invalidation of
- * string representations.)
+ * If the flags argument is zero or DICT_PATH_EXISTS, there are
+ * no side effects (other than potential conversion of objects to
+ * dictionaries.) If the flags argument is DICT_PATH_UPDATE, the
+ * following additional side effects occur. Shared dictionaries
+ * along the path are converted into unshared objects, and a
+ * backward-pointing chain is built using the chain fields of the
+ * dictionaries (for easy invalidation of string
+ * representations.)
*
*----------------------------------------------------------------------
*/
static Tcl_Obj *
-TraceDictPath(interp, dictPtr, keyc, keyv, willUpdate)
+TraceDictPath(interp, dictPtr, keyc, keyv, flags)
Tcl_Interp *interp;
Tcl_Obj *dictPtr, *CONST keyv[];
- int keyc, willUpdate;
+ int keyc, flags;
{
Dict *dict, *newDict;
int i;
@@ -574,7 +594,7 @@ TraceDictPath(interp, dictPtr, keyc, keyv, willUpdate)
}
}
dict = (Dict *) dictPtr->internalRep.otherValuePtr;
- if (willUpdate) {
+ if (flags == DICT_PATH_UPDATE) {
dict->chain = NULL;
}
@@ -583,6 +603,9 @@ TraceDictPath(interp, dictPtr, keyc, keyv, willUpdate)
Tcl_Obj *tmpObj;
if (hPtr == NULL) {
+ if (flags == DICT_PATH_EXISTS) {
+ return DICT_PATH_NON_EXISTENT;
+ }
if (interp != NULL) {
Tcl_ResetResult(interp);
Tcl_AppendStringsToObj(Tcl_GetObjResult(interp),
@@ -599,7 +622,7 @@ TraceDictPath(interp, dictPtr, keyc, keyv, willUpdate)
}
}
newDict = (Dict *) tmpObj->internalRep.otherValuePtr;
- if (willUpdate) {
+ if (flags == DICT_PATH_UPDATE) {
if (Tcl_IsShared(tmpObj)) {
Tcl_DecrRefCount(tmpObj);
tmpObj = Tcl_DuplicateObj(tmpObj);
@@ -1032,7 +1055,7 @@ Tcl_DictObjPutKeyList(interp, dictPtr, keyc, keyv, valuePtr)
Tcl_Panic("Tcl_DictObjPutKeyList called with empty key list");
}
- dictPtr = TraceDictPath(interp, dictPtr, keyc-1, keyv, /*willUpdate*/ 1);
+ dictPtr = TraceDictPath(interp, dictPtr, keyc-1, keyv, DICT_PATH_UPDATE);
if (dictPtr == NULL) {
return TCL_ERROR;
}
@@ -1088,7 +1111,7 @@ Tcl_DictObjRemoveKeyList(interp, dictPtr, keyc, keyv)
Tcl_Panic("Tcl_DictObjRemoveKeyList called with empty key list");
}
- dictPtr = TraceDictPath(interp, dictPtr, keyc-1, keyv, /*willUpdate*/ 1);
+ dictPtr = TraceDictPath(interp, dictPtr, keyc-1, keyv, DICT_PATH_UPDATE);
if (dictPtr == NULL) {
return TCL_ERROR;
}
@@ -1320,7 +1343,7 @@ DictGetCmd(interp, objc, objv)
* going through a chain of searches.) Note that this loop always
* executes at least once.
*/
- dictPtr = TraceDictPath(interp, objv[2], objc-4, objv+3, /*willUpdate*/ 0);
+ dictPtr = TraceDictPath(interp, objv[2], objc-4, objv+3, 0);
if (dictPtr == NULL) {
return TCL_ERROR;
}
@@ -1618,10 +1641,14 @@ DictExistsCmd(interp, objc, objv)
return TCL_ERROR;
}
- dictPtr = TraceDictPath(interp, objv[2], objc-4, objv+3, /*willUpdate*/ 0);
+ dictPtr = TraceDictPath(interp, objv[2], objc-4, objv+3, DICT_PATH_EXISTS);
if (dictPtr == NULL) {
return TCL_ERROR;
}
+ if (dictPtr == DICT_PATH_NON_EXISTENT) {
+ Tcl_SetObjResult(interp, Tcl_NewBooleanObj(0));
+ return TCL_OK;
+ }
result = Tcl_DictObjGet(interp, dictPtr, objv[objc-1], &valuePtr);
if (result != TCL_OK) {
return result;