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dashley |
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/* $Header$ */
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dashley |
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/*
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* tclResolve.c --
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*
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* Contains hooks for customized command/variable name resolution
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* schemes. These hooks allow extensions like [incr Tcl] to add
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* their own name resolution rules to the Tcl language. Rules can
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* be applied to a particular namespace, to the interpreter as a
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* whole, or both.
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*
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* Copyright (c) 1998 Lucent Technologies, Inc.
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*
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* See the file "license.terms" for information on usage and redistribution
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* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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*
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* RCS: @(#) $Id: tclresolve.c,v 1.1.1.1 2001/06/13 04:45:45 dtashley Exp $
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*/
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#include "tclInt.h"
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/*
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* Declarations for procedures local to this file:
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*/
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static void BumpCmdRefEpochs _ANSI_ARGS_((Namespace *nsPtr));
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_AddInterpResolvers --
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*
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* Adds a set of command/variable resolution procedures to an
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* interpreter. These procedures are consulted when commands
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* are resolved in Tcl_FindCommand, and when variables are
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* resolved in TclLookupVar and LookupCompiledLocal. Each
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* namespace may also have its own set of resolution procedures
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* which take precedence over those for the interpreter.
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*
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* When a name is resolved, it is handled as follows. First,
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* the name is passed to the resolution procedures for the
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* namespace. If not resolved, the name is passed to each of
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* the resolution procedures added to the interpreter. Finally,
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* if still not resolved, the name is handled using the default
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* Tcl rules for name resolution.
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*
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* Results:
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* Returns pointers to the current name resolution procedures
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* in the cmdProcPtr, varProcPtr and compiledVarProcPtr
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* arguments.
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*
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* Side effects:
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* If a compiledVarProc is specified, this procedure bumps the
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* compileEpoch for the interpreter, forcing all code to be
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* recompiled. If a cmdProc is specified, this procedure bumps
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* the cmdRefEpoch in all namespaces, forcing commands to be
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* resolved again using the new rules.
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*
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*----------------------------------------------------------------------
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*/
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void
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Tcl_AddInterpResolvers(interp, name, cmdProc, varProc, compiledVarProc)
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Tcl_Interp *interp; /* Interpreter whose name resolution
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* rules are being modified. */
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char *name; /* Name of this resolution scheme. */
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Tcl_ResolveCmdProc *cmdProc; /* New procedure for command
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* resolution */
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Tcl_ResolveVarProc *varProc; /* Procedure for variable resolution
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* at runtime */
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Tcl_ResolveCompiledVarProc *compiledVarProc;
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/* Procedure for variable resolution
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* at compile time. */
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{
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Interp *iPtr = (Interp*)interp;
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ResolverScheme *resPtr;
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/*
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* Since we're adding a new name resolution scheme, we must force
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* all code to be recompiled to use the new scheme. If there
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* are new compiled variable resolution rules, bump the compiler
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* epoch to invalidate compiled code. If there are new command
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* resolution rules, bump the cmdRefEpoch in all namespaces.
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*/
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if (compiledVarProc) {
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iPtr->compileEpoch++;
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}
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if (cmdProc) {
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BumpCmdRefEpochs(iPtr->globalNsPtr);
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}
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/*
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* Look for an existing scheme with the given name. If found,
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* then replace its rules.
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*/
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for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
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if (*name == *resPtr->name && strcmp(name, resPtr->name) == 0) {
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resPtr->cmdResProc = cmdProc;
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resPtr->varResProc = varProc;
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resPtr->compiledVarResProc = compiledVarProc;
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return;
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}
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}
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/*
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* Otherwise, this is a new scheme. Add it to the FRONT
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* of the linked list, so that it overrides existing schemes.
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*/
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resPtr = (ResolverScheme *) ckalloc(sizeof(ResolverScheme));
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resPtr->name = (char*)ckalloc((unsigned)(strlen(name)+1));
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strcpy(resPtr->name, name);
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resPtr->cmdResProc = cmdProc;
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resPtr->varResProc = varProc;
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resPtr->compiledVarResProc = compiledVarProc;
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resPtr->nextPtr = iPtr->resolverPtr;
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iPtr->resolverPtr = resPtr;
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_GetInterpResolvers --
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*
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* Looks for a set of command/variable resolution procedures with
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* the given name in an interpreter. These procedures are
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* registered by calling Tcl_AddInterpResolvers.
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*
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* Results:
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* If the name is recognized, this procedure returns non-zero,
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* along with pointers to the name resolution procedures in
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* the Tcl_ResolverInfo structure. If the name is not recognized,
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* this procedure returns zero.
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*
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* Side effects:
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* None.
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*
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*----------------------------------------------------------------------
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*/
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int
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Tcl_GetInterpResolvers(interp, name, resInfoPtr)
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Tcl_Interp *interp; /* Interpreter whose name resolution
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* rules are being queried. */
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char *name; /* Look for a scheme with this name. */
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Tcl_ResolverInfo *resInfoPtr; /* Returns pointers to the procedures,
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* if found */
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{
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Interp *iPtr = (Interp*)interp;
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ResolverScheme *resPtr;
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/*
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* Look for an existing scheme with the given name. If found,
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* then return pointers to its procedures.
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*/
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for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
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if (*name == *resPtr->name && strcmp(name, resPtr->name) == 0) {
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resInfoPtr->cmdResProc = resPtr->cmdResProc;
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resInfoPtr->varResProc = resPtr->varResProc;
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resInfoPtr->compiledVarResProc = resPtr->compiledVarResProc;
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return 1;
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}
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}
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return 0;
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}
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/*
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*----------------------------------------------------------------------
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*
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* Tcl_RemoveInterpResolvers --
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*
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* Removes a set of command/variable resolution procedures
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* previously added by Tcl_AddInterpResolvers. The next time
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* a command/variable name is resolved, these procedures
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* won't be consulted.
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*
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* Results:
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* Returns non-zero if the name was recognized and the
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* resolution scheme was deleted. Returns zero otherwise.
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*
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* Side effects:
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* If a scheme with a compiledVarProc was deleted, this procedure
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* bumps the compileEpoch for the interpreter, forcing all code
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* to be recompiled. If a scheme with a cmdProc was deleted,
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* this procedure bumps the cmdRefEpoch in all namespaces,
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* forcing commands to be resolved again using the new rules.
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*
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*----------------------------------------------------------------------
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*/
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int
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Tcl_RemoveInterpResolvers(interp, name)
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Tcl_Interp *interp; /* Interpreter whose name resolution
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* rules are being modified. */
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char *name; /* Name of the scheme to be removed. */
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{
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Interp *iPtr = (Interp*)interp;
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ResolverScheme **prevPtrPtr, *resPtr;
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/*
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* Look for an existing scheme with the given name.
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*/
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prevPtrPtr = &iPtr->resolverPtr;
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for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
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if (*name == *resPtr->name && strcmp(name, resPtr->name) == 0) {
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break;
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}
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prevPtrPtr = &resPtr->nextPtr;
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}
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/*
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* If we found the scheme, delete it.
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*/
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if (resPtr) {
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/*
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* If we're deleting a scheme with compiled variable resolution
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* rules, bump the compiler epoch to invalidate compiled code.
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* If we're deleting a scheme with command resolution rules,
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* bump the cmdRefEpoch in all namespaces.
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*/
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if (resPtr->compiledVarResProc) {
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iPtr->compileEpoch++;
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}
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if (resPtr->cmdResProc) {
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BumpCmdRefEpochs(iPtr->globalNsPtr);
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}
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*prevPtrPtr = resPtr->nextPtr;
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ckfree(resPtr->name);
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ckfree((char *) resPtr);
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return 1;
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}
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return 0;
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}
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/*
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*----------------------------------------------------------------------
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*
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* BumpCmdRefEpochs --
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*
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* This procedure is used to bump the cmdRefEpoch counters in
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* the specified namespace and all of its child namespaces.
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* It is used whenever name resolution schemes are added/removed
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* from an interpreter, to invalidate all command references.
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*
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* Results:
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* None.
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*
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* Side effects:
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* Bumps the cmdRefEpoch in the specified namespace and its
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* children, recursively.
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*
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*----------------------------------------------------------------------
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*/
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static void
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BumpCmdRefEpochs(nsPtr)
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Namespace *nsPtr; /* Namespace being modified. */
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{
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264 |
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Tcl_HashEntry *entry;
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Tcl_HashSearch search;
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Namespace *childNsPtr;
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nsPtr->cmdRefEpoch++;
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for (entry = Tcl_FirstHashEntry(&nsPtr->childTable, &search);
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entry != NULL;
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entry = Tcl_NextHashEntry(&search)) {
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273 |
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childNsPtr = (Namespace *) Tcl_GetHashValue(entry);
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BumpCmdRefEpochs(childNsPtr);
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}
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}
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279 |
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/*
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281 |
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*----------------------------------------------------------------------
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282 |
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*
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283 |
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* Tcl_SetNamespaceResolvers --
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284 |
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*
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285 |
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* Sets the command/variable resolution procedures for a namespace,
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286 |
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* thereby changing the way that command/variable names are
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* interpreted. This allows extension writers to support different
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288 |
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* name resolution schemes, such as those for object-oriented
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289 |
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* packages.
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290 |
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*
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291 |
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* Command resolution is handled by a procedure of the following
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292 |
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* type:
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293 |
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*
|
294 |
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* typedef int (Tcl_ResolveCmdProc) _ANSI_ARGS_((
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295 |
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* Tcl_Interp* interp, char* name, Tcl_Namespace *context,
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296 |
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* int flags, Tcl_Command *rPtr));
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297 |
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*
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298 |
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* Whenever a command is executed or Tcl_FindCommand is invoked
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299 |
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* within the namespace, this procedure is called to resolve the
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300 |
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* command name. If this procedure is able to resolve the name,
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301 |
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* it should return the status code TCL_OK, along with the
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302 |
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* corresponding Tcl_Command in the rPtr argument. Otherwise,
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303 |
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* the procedure can return TCL_CONTINUE, and the command will
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304 |
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* be treated under the usual name resolution rules. Or, it can
|
305 |
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* return TCL_ERROR, and the command will be considered invalid.
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306 |
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*
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307 |
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* Variable resolution is handled by two procedures. The first
|
308 |
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* is called whenever a variable needs to be resolved at compile
|
309 |
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* time:
|
310 |
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*
|
311 |
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* typedef int (Tcl_ResolveCompiledVarProc) _ANSI_ARGS_((
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312 |
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* Tcl_Interp* interp, char* name, Tcl_Namespace *context,
|
313 |
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* Tcl_ResolvedVarInfo *rPtr));
|
314 |
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*
|
315 |
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* If this procedure is able to resolve the name, it should return
|
316 |
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* the status code TCL_OK, along with variable resolution info in
|
317 |
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* the rPtr argument; this info will be used to set up compiled
|
318 |
|
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* locals in the call frame at runtime. The procedure may also
|
319 |
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* return TCL_CONTINUE, and the variable will be treated under
|
320 |
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* the usual name resolution rules. Or, it can return TCL_ERROR,
|
321 |
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* and the variable will be considered invalid.
|
322 |
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*
|
323 |
|
|
* Another procedure is used whenever a variable needs to be
|
324 |
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* resolved at runtime but it is not recognized as a compiled local.
|
325 |
|
|
* (For example, the variable may be requested via
|
326 |
|
|
* Tcl_FindNamespaceVar.) This procedure has the following type:
|
327 |
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|
*
|
328 |
|
|
* typedef int (Tcl_ResolveVarProc) _ANSI_ARGS_((
|
329 |
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|
* Tcl_Interp* interp, char* name, Tcl_Namespace *context,
|
330 |
|
|
* int flags, Tcl_Var *rPtr));
|
331 |
|
|
*
|
332 |
|
|
* This procedure is quite similar to the compile-time version.
|
333 |
|
|
* It returns the same status codes, but if variable resolution
|
334 |
|
|
* succeeds, this procedure returns a Tcl_Var directly via the
|
335 |
|
|
* rPtr argument.
|
336 |
|
|
*
|
337 |
|
|
* Results:
|
338 |
|
|
* Nothing.
|
339 |
|
|
*
|
340 |
|
|
* Side effects:
|
341 |
|
|
* Bumps the command epoch counter for the namespace, invalidating
|
342 |
|
|
* all command references in that namespace. Also bumps the
|
343 |
|
|
* resolver epoch counter for the namespace, forcing all code
|
344 |
|
|
* in the namespace to be recompiled.
|
345 |
|
|
*
|
346 |
|
|
*----------------------------------------------------------------------
|
347 |
|
|
*/
|
348 |
|
|
|
349 |
|
|
void
|
350 |
|
|
Tcl_SetNamespaceResolvers(namespacePtr, cmdProc, varProc, compiledVarProc)
|
351 |
|
|
Tcl_Namespace *namespacePtr; /* Namespace whose resolution rules
|
352 |
|
|
* are being modified. */
|
353 |
|
|
Tcl_ResolveCmdProc *cmdProc; /* Procedure for command resolution */
|
354 |
|
|
Tcl_ResolveVarProc *varProc; /* Procedure for variable resolution
|
355 |
|
|
* at runtime */
|
356 |
|
|
Tcl_ResolveCompiledVarProc *compiledVarProc;
|
357 |
|
|
/* Procedure for variable resolution
|
358 |
|
|
* at compile time. */
|
359 |
|
|
{
|
360 |
|
|
Namespace *nsPtr = (Namespace*)namespacePtr;
|
361 |
|
|
|
362 |
|
|
/*
|
363 |
|
|
* Plug in the new command resolver, and bump the epoch counters
|
364 |
|
|
* so that all code will have to be recompiled and all commands
|
365 |
|
|
* will have to be resolved again using the new policy.
|
366 |
|
|
*/
|
367 |
|
|
nsPtr->cmdResProc = cmdProc;
|
368 |
|
|
nsPtr->varResProc = varProc;
|
369 |
|
|
nsPtr->compiledVarResProc = compiledVarProc;
|
370 |
|
|
|
371 |
|
|
nsPtr->cmdRefEpoch++;
|
372 |
|
|
nsPtr->resolverEpoch++;
|
373 |
|
|
}
|
374 |
|
|
|
375 |
|
|
/*
|
376 |
|
|
*----------------------------------------------------------------------
|
377 |
|
|
*
|
378 |
|
|
* Tcl_GetNamespaceResolvers --
|
379 |
|
|
*
|
380 |
|
|
* Returns the current command/variable resolution procedures
|
381 |
|
|
* for a namespace. By default, these procedures are NULL.
|
382 |
|
|
* New procedures can be installed by calling
|
383 |
|
|
* Tcl_SetNamespaceResolvers, to provide new name resolution
|
384 |
|
|
* rules.
|
385 |
|
|
*
|
386 |
|
|
* Results:
|
387 |
|
|
* Returns non-zero if any name resolution procedures have been
|
388 |
|
|
* assigned to this namespace; also returns pointers to the
|
389 |
|
|
* procedures in the Tcl_ResolverInfo structure. Returns zero
|
390 |
|
|
* otherwise.
|
391 |
|
|
*
|
392 |
|
|
* Side effects:
|
393 |
|
|
* None.
|
394 |
|
|
*
|
395 |
|
|
*----------------------------------------------------------------------
|
396 |
|
|
*/
|
397 |
|
|
|
398 |
|
|
int
|
399 |
|
|
Tcl_GetNamespaceResolvers(namespacePtr, resInfoPtr)
|
400 |
|
|
|
401 |
|
|
Tcl_Namespace *namespacePtr; /* Namespace whose resolution rules
|
402 |
|
|
* are being modified. */
|
403 |
|
|
Tcl_ResolverInfo *resInfoPtr; /* Returns: pointers for all
|
404 |
|
|
* name resolution procedures
|
405 |
|
|
* assigned to this namespace. */
|
406 |
|
|
{
|
407 |
|
|
Namespace *nsPtr = (Namespace*)namespacePtr;
|
408 |
|
|
|
409 |
|
|
resInfoPtr->cmdResProc = nsPtr->cmdResProc;
|
410 |
|
|
resInfoPtr->varResProc = nsPtr->varResProc;
|
411 |
|
|
resInfoPtr->compiledVarResProc = nsPtr->compiledVarResProc;
|
412 |
|
|
|
413 |
|
|
if (nsPtr->cmdResProc != NULL ||
|
414 |
|
|
nsPtr->varResProc != NULL ||
|
415 |
|
|
nsPtr->compiledVarResProc != NULL) {
|
416 |
|
|
return 1;
|
417 |
|
|
}
|
418 |
|
|
return 0;
|
419 |
|
|
}
|
420 |
|
|
|
421 |
dashley |
66 |
/* End of tclresolve.c */
|