tclIndexObj.c Go to the documentation of this file. /* * tclIndexObj.c -- * * This file implements objects of type "index". This object type is used * to lookup a keyword in a table of valid values and cache the index of * the matching entry. * * Copyright (c) 1997 Sun Microsystems, Inc. * * See the file "license.terms" for information on usage and redistribution of * this file, and for a DISCLAIMER OF ALL WARRANTIES. * * RCS: @(#) $Id: tclIndexObj.c,v 1.38 2007/12/13 15:23:18 dgp Exp $ */ #include "tclInt.h" /* * Prototypes for functions defined later in this file: */ static int SetIndexFromAny(Tcl_Interp *interp, Tcl_Obj *objPtr); static void UpdateStringOfIndex(Tcl_Obj *objPtr); static void DupIndex(Tcl_Obj *srcPtr, Tcl_Obj *dupPtr); static void FreeIndex(Tcl_Obj *objPtr); /* * The structure below defines the index Tcl object type by means of functions * that can be invoked by generic object code. */ static Tcl_ObjType indexType = { "index", /* name */ FreeIndex, /* freeIntRepProc */ DupIndex, /* dupIntRepProc */ UpdateStringOfIndex, /* updateStringProc */ SetIndexFromAny /* setFromAnyProc */ }; /* * The definition of the internal representation of the "index" object; The * internalRep.otherValuePtr field of an object of "index" type will be a * pointer to one of these structures. * * Keep this structure declaration in sync with tclTestObj.c */ typedef struct { void *tablePtr; /* Pointer to the table of strings */ int offset; /* Offset between table entries */ int index; /* Selected index into table. */ } IndexRep; /* * The following macros greatly simplify moving through a table... */ #define STRING_AT(table, offset, index) \ (*((const char *const *)(((char *)(table)) + ((offset) * (index))))) #define NEXT_ENTRY(table, offset) \ (&(STRING_AT(table, offset, 1))) #define EXPAND_OF(indexRep) \ STRING_AT((indexRep)->tablePtr, (indexRep)->offset, (indexRep)->index)  /* *---------------------------------------------------------------------- * * Tcl_GetIndexFromObj -- * * This function looks up an object's value in a table of strings and * returns the index of the matching string, if any. * * Results: * If the value of objPtr is identical to or a unique abbreviation for * one of the entries in objPtr, then the return value is TCL_OK and the * index of the matching entry is stored at *indexPtr. If there isn't a * proper match, then TCL_ERROR is returned and an error message is left * in interp's result (unless interp is NULL). The msg argument is used * in the error message; for example, if msg has the value "option" then * the error message will say something flag 'bad option "foo": must be * ...' * * Side effects: * The result of the lookup is cached as the internal rep of objPtr, so * that repeated lookups can be done quickly. * *---------------------------------------------------------------------- */ int Tcl_GetIndexFromObj( Tcl_Interp *interp, /* Used for error reporting if not NULL. */ Tcl_Obj *objPtr, /* Object containing the string to lookup. */ const char **tablePtr, /* Array of strings to compare against the * value of objPtr; last entry must be NULL * and there must not be duplicate entries. */ const char *msg, /* Identifying word to use in error * messages. */ int flags, /* 0 or TCL_EXACT */ int *indexPtr) /* Place to store resulting integer index. */ { /* * See if there is a valid cached result from a previous lookup (doing the * check here saves the overhead of calling Tcl_GetIndexFromObjStruct in * the common case where the result is cached). */ if (objPtr->typePtr == &indexType) { IndexRep *indexRep = objPtr->internalRep.otherValuePtr; /* * Here's hoping we don't get hit by unfortunate packing constraints * on odd platforms like a Cray PVP... */ if (indexRep->tablePtr == (void *) tablePtr && indexRep->offset == sizeof(char *)) { *indexPtr = indexRep->index; return TCL_OK; } } return Tcl_GetIndexFromObjStruct(interp, objPtr, tablePtr, sizeof(char *), msg, flags, indexPtr); }  /* *---------------------------------------------------------------------- * * Tcl_GetIndexFromObjStruct -- * * This function looks up an object's value given a starting string and * an offset for the amount of space between strings. This is useful when * the strings are embedded in some other kind of array. * * Results: * If the value of objPtr is identical to or a unique abbreviation for * one of the entries in objPtr, then the return value is TCL_OK and the * index of the matching entry is stored at *indexPtr. If there isn't a * proper match, then TCL_ERROR is returned and an error message is left * in interp's result (unless interp is NULL). The msg argument is used * in the error message; for example, if msg has the value "option" then * the error message will say something flag 'bad option "foo": must be * ...' * * Side effects: * The result of the lookup is cached as the internal rep of objPtr, so * that repeated lookups can be done quickly. * *---------------------------------------------------------------------- */ int Tcl_GetIndexFromObjStruct( Tcl_Interp *interp, /* Used for error reporting if not NULL. */ Tcl_Obj *objPtr, /* Object containing the string to lookup. */ const void *tablePtr, /* The first string in the table. The second * string will be at this address plus the * offset, the third plus the offset again, * etc. The last entry must be NULL and there * must not be duplicate entries. */ int offset, /* The number of bytes between entries */ const char *msg, /* Identifying word to use in error * messages. */ int flags, /* 0 or TCL_EXACT */ int *indexPtr) /* Place to store resulting integer index. */ { int index, idx, numAbbrev; char *key, *p1; const char *p2; const char *const *entryPtr; Tcl_Obj *resultPtr; IndexRep *indexRep; /* * See if there is a valid cached result from a previous lookup. */ if (objPtr->typePtr == &indexType) { indexRep = objPtr->internalRep.otherValuePtr; if (indexRep->tablePtr==tablePtr && indexRep->offset==offset) { *indexPtr = indexRep->index; return TCL_OK; } } /* * Lookup the value of the object in the table. Accept unique * abbreviations unless TCL_EXACT is set in flags. */ key = TclGetString(objPtr); index = -1; numAbbrev = 0; /* * Scan the table looking for one of: * - An exact match (always preferred) * - A single abbreviation (allowed depending on flags) * - Several abbreviations (never allowed, but overridden by exact match) */ for (entryPtr = tablePtr, idx = 0; *entryPtr != NULL; entryPtr = NEXT_ENTRY(entryPtr, offset), idx++) { for (p1 = key, p2 = *entryPtr; *p1 == *p2; p1++, p2++) { if (*p1 == '\0') { index = idx; goto done; } } if (*p1 == '\0') { /* * The value is an abbreviation for this entry. Continue checking * other entries to make sure it's unique. If we get more than one * unique abbreviation, keep searching to see if there is an exact * match, but remember the number of unique abbreviations and * don't allow either. */ numAbbrev++; index = idx; } } /* * Check if we were instructed to disallow abbreviations. */ if ((flags & TCL_EXACT) || (key[0] == '\0') || (numAbbrev != 1)) { goto error; } done: /* * Cache the found representation. Note that we want to avoid allocating a * new internal-rep if at all possible since that is potentially a slow * operation. */ if (objPtr->typePtr == &indexType) { indexRep = objPtr->internalRep.otherValuePtr; } else { TclFreeIntRep(objPtr); indexRep = (IndexRep *) ckalloc(sizeof(IndexRep)); objPtr->internalRep.otherValuePtr = indexRep; objPtr->typePtr = &indexType; } indexRep->tablePtr = (void *) tablePtr; indexRep->offset = offset; indexRep->index = index; *indexPtr = index; return TCL_OK; error: if (interp != NULL) { /* * Produce a fancy error message. */ int count; TclNewObj(resultPtr); Tcl_SetObjResult(interp, resultPtr); Tcl_AppendStringsToObj(resultPtr, (numAbbrev > 1) && !(flags & TCL_EXACT) ? "ambiguous " : "bad ", msg, " \"", key, "\": must be ", STRING_AT(tablePtr, offset, 0), NULL); for (entryPtr = NEXT_ENTRY(tablePtr, offset), count = 0; *entryPtr != NULL; entryPtr = NEXT_ENTRY(entryPtr, offset), count++) { if (*NEXT_ENTRY(entryPtr, offset) == NULL) { Tcl_AppendStringsToObj(resultPtr, ((count > 0) ? "," : ""), " or ", *entryPtr, NULL); } else { Tcl_AppendStringsToObj(resultPtr, ", ", *entryPtr, NULL); } } Tcl_SetErrorCode(interp, "TCL", "LOOKUP", "INDEX", msg, key, NULL); } return TCL_ERROR; }  /* *---------------------------------------------------------------------- * * SetIndexFromAny -- * * This function is called to convert a Tcl object to index internal * form. However, this doesn't make sense (need to have a table of * keywords in order to do the conversion) so the function always * generates an error. * * Results: * The return value is always TCL_ERROR, and an error message is left in * interp's result if interp isn't NULL. * * Side effects: * None. * *---------------------------------------------------------------------- */ static int SetIndexFromAny( Tcl_Interp *interp, /* Used for error reporting if not NULL. */ register Tcl_Obj *objPtr) /* The object to convert. */ { Tcl_SetObjResult(interp, Tcl_NewStringObj( "can't convert value to index except via Tcl_GetIndexFromObj API", -1)); return TCL_ERROR; }  /* *---------------------------------------------------------------------- * * UpdateStringOfIndex -- * * This function is called to convert a Tcl object from index internal * form to its string form. No abbreviation is ever generated. * * Results: * None. * * Side effects: * The string representation of the object is updated. * *---------------------------------------------------------------------- */ static void UpdateStringOfIndex( Tcl_Obj *objPtr) { IndexRep *indexRep = objPtr->internalRep.otherValuePtr; register char *buf; register unsigned len; register const char *indexStr = EXPAND_OF(indexRep); len = strlen(indexStr); buf = (char *) ckalloc(len + 1); memcpy(buf, indexStr, len+1); objPtr->bytes = buf; objPtr->length = len; }  /* *---------------------------------------------------------------------- * * DupIndex -- * * This function is called to copy the internal rep of an index Tcl * object from to another object. * * Results: * None. * * Side effects: * The internal representation of the target object is updated and the * type is set. * *---------------------------------------------------------------------- */ static void DupIndex( Tcl_Obj *srcPtr, Tcl_Obj *dupPtr) { IndexRep *srcIndexRep = srcPtr->internalRep.otherValuePtr; IndexRep *dupIndexRep = (IndexRep *) ckalloc(sizeof(IndexRep)); memcpy(dupIndexRep, srcIndexRep, sizeof(IndexRep)); dupPtr->internalRep.otherValuePtr = dupIndexRep; dupPtr->typePtr = &indexType; }  /* *---------------------------------------------------------------------- * * FreeIndex -- * * This function is called to delete the internal rep of an index Tcl * object. * * Results: * None. * * Side effects: * The internal representation of the target object is deleted. * *---------------------------------------------------------------------- */ static void FreeIndex( Tcl_Obj *objPtr) { ckfree((char *) objPtr->internalRep.otherValuePtr); }  /* *---------------------------------------------------------------------- * * Tcl_WrongNumArgs -- * * This function generates a "wrong # args" error message in an * interpreter. It is used as a utility function by many command * functions, including the function that implements procedures. * * Results: * None. * * Side effects: * An error message is generated in interp's result object to indicate * that a command was invoked with the wrong number of arguments. The * message has the form * wrong # args: should be "foo bar additional stuff" * where "foo" and "bar" are the initial objects in objv (objc determines * how many of these are printed) and "additional stuff" is the contents * of the message argument. * * The message printed is modified somewhat if the command is wrapped * inside an ensemble. In that case, the error message generated is * rewritten in such a way that it appears to be generated from the * user-visible command and not how that command is actually implemented, * giving a better overall user experience. * * Internally, the Tcl core may set the flag INTERP_ALTERNATE_WRONG_ARGS * in the interpreter to generate complex multi-part messages by calling * this function repeatedly. This allows the code that knows how to * handle ensemble-related error messages to be kept here while still * generating suitable error messages for commands like [read] and * [socket]. Ideally, this would be done through an extra flags argument, * but that wouldn't be source-compatible with the existing API and it's * a fairly rare requirement anyway. * *---------------------------------------------------------------------- */ void Tcl_WrongNumArgs( Tcl_Interp *interp, /* Current interpreter. */ int objc, /* Number of arguments to print from objv. */ Tcl_Obj *const objv[], /* Initial argument objects, which should be * included in the error message. */ const char *message) /* Error message to print after the leading * objects in objv. The message may be * NULL. */ { Tcl_Obj *objPtr; int i, len, elemLen, flags; Interp *iPtr = (Interp *) interp; const char *elementStr; /* * [incr Tcl] does something fairly horrific when generating error * messages for its ensembles; it passes the whole set of ensemble * arguments as a list in the first argument. This means that this code * causes a problem in iTcl if it attempts to correctly quote all * arguments, which would be the correct thing to do. We work around this * nasty behaviour for now, and hope that we can remove it all in the * future... */ #ifndef AVOID_HACKS_FOR_ITCL int isFirst = 1; /* Special flag used to inhibit the treating * of the first word as a list element so the * hacky way Itcl generates error messages for * its ensembles will still work. [Bug * 1066837] */ # define MAY_QUOTE_WORD (!isFirst) # define AFTER_FIRST_WORD (isFirst = 0) #else /* !AVOID_HACKS_FOR_ITCL */ # define MAY_QUOTE_WORD 1 # define AFTER_FIRST_WORD (void) 0 #endif /* AVOID_HACKS_FOR_ITCL */ TclNewObj(objPtr); if (iPtr->flags & INTERP_ALTERNATE_WRONG_ARGS) { Tcl_AppendObjToObj(objPtr, Tcl_GetObjResult(interp)); Tcl_AppendToObj(objPtr, " or \"", -1); } else { Tcl_AppendToObj(objPtr, "wrong # args: should be \"", -1); } /* * Check to see if we are processing an ensemble implementation, and if so * rewrite the results in terms of how the ensemble was invoked. */ if (iPtr->ensembleRewrite.sourceObjs != NULL) { int toSkip = iPtr->ensembleRewrite.numInsertedObjs; int toPrint = iPtr->ensembleRewrite.numRemovedObjs; Tcl_Obj *const *origObjv = iPtr->ensembleRewrite.sourceObjs; /* * We only know how to do rewriting if all the replaced objects are * actually arguments (in objv) to this function. Otherwise it just * gets too complicated and we'd be better off just giving a slightly * confusing error message... */ if (objc < toSkip) { goto addNormalArgumentsToMessage; } /* * Strip out the actual arguments that the ensemble inserted. */ objv += toSkip; objc -= toSkip; /* * We assume no object is of index type. */ for (i=0 ; i<toPrint ; i++) { /* * Add the element, quoting it if necessary. */ if (origObjv[i]->typePtr == &indexType) { register IndexRep *indexRep = origObjv[i]->internalRep.otherValuePtr; elementStr = EXPAND_OF(indexRep); elemLen = strlen(elementStr); } else if (origObjv[i]->typePtr == &tclEnsembleCmdType) { register EnsembleCmdRep *ecrPtr = origObjv[i]->internalRep.otherValuePtr; elementStr = ecrPtr->fullSubcmdName; elemLen = strlen(elementStr); } else { elementStr = TclGetStringFromObj(origObjv[i], &elemLen); } len = Tcl_ScanCountedElement(elementStr, elemLen, &flags); if (MAY_QUOTE_WORD && len != elemLen) { char *quotedElementStr = TclStackAlloc(interp, (unsigned)len); len = Tcl_ConvertCountedElement(elementStr, elemLen, quotedElementStr, flags); Tcl_AppendToObj(objPtr, quotedElementStr, len); TclStackFree(interp, quotedElementStr); } else { Tcl_AppendToObj(objPtr, elementStr, elemLen); } AFTER_FIRST_WORD; /* * Add a space if the word is not the last one (which has a * moderately complex condition here). */ if (i<toPrint-1 || objc!=0 || message!=NULL) { Tcl_AppendStringsToObj(objPtr, " ", NULL); } } } /* * Now add the arguments (other than those rewritten) that the caller took * from its calling context. */ addNormalArgumentsToMessage: for (i = 0; i < objc; i++) { /* * If the object is an index type use the index table which allows for * the correct error message even if the subcommand was abbreviated. * Otherwise, just use the string rep. */ if (objv[i]->typePtr == &indexType) { register IndexRep *indexRep = objv[i]->internalRep.otherValuePtr; Tcl_AppendStringsToObj(objPtr, EXPAND_OF(indexRep), NULL); } else if (objv[i]->typePtr == &tclEnsembleCmdType) { register EnsembleCmdRep *ecrPtr = objv[i]->internalRep.otherValuePtr; Tcl_AppendStringsToObj(objPtr, ecrPtr->fullSubcmdName, NULL); } else { /* * Quote the argument if it contains spaces (Bug 942757). */ elementStr = TclGetStringFromObj(objv[i], &elemLen); len = Tcl_ScanCountedElement(elementStr, elemLen, &flags); if (MAY_QUOTE_WORD && len != elemLen) { char *quotedElementStr = TclStackAlloc(interp,(unsigned) len); len = Tcl_ConvertCountedElement(elementStr, elemLen, quotedElementStr, flags); Tcl_AppendToObj(objPtr, quotedElementStr, len); TclStackFree(interp, quotedElementStr); } else { Tcl_AppendToObj(objPtr, elementStr, elemLen); } } AFTER_FIRST_WORD; /* * Append a space character (" ") if there is more text to follow * (either another element from objv, or the message string). */ if (i<objc-1 || message!=NULL) { Tcl_AppendStringsToObj(objPtr, " ", NULL); } } /* * Add any trailing message bits and set the resulting string as the * interpreter result. Caller is responsible for reporting this as an * actual error. */ if (message != NULL) { Tcl_AppendStringsToObj(objPtr, message, NULL); } Tcl_AppendStringsToObj(objPtr, "\"", NULL); Tcl_SetObjResult(interp, objPtr); #undef MAY_QUOTE_WORD #undef AFTER_FIRST_WORD }  /* * Local Variables: * mode: c * c-basic-offset: 4 * fill-column: 78 * End: */

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