Initial revision

1 files changed, 697 insertions, 0 deletions

diff --git a/generic/tclEvent.c b/generic/tclEvent.c
new file mode 100644
index 0000000..4672982
--- /dev/null
+++ b/generic/tclEvent.c
@@ -0,0 +1,697 @@
+/* 
+ * tclEvent.c --
+ *
+ *	This file implements some general event related interfaces including
+ *	background errors, exit handlers, and the "vwait" and "update"
+ *	command procedures. 
+ *
+ * Copyright (c) 1990-1994 The Regents of the University of California.
+ * Copyright (c) 1994-1997 Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * SCCS: @(#) tclEvent.c 1.153 97/08/11 20:22:31
+ */
+
+#include "tclInt.h"
+#include "tclPort.h"
+
+/*
+ * The data structure below is used to report background errors.  One
+ * such structure is allocated for each error;  it holds information
+ * about the interpreter and the error until bgerror can be invoked
+ * later as an idle handler.
+ */
+
+typedef struct BgError {
+    Tcl_Interp *interp;		/* Interpreter in which error occurred.  NULL
+				 * means this error report has been cancelled
+				 * (a previous report generated a break). */
+    char *errorMsg;		/* The error message (interp->result when
+				 * the error occurred).  Malloc-ed. */
+    char *errorInfo;		/* Value of the errorInfo variable
+				 * (malloc-ed). */
+    char *errorCode;		/* Value of the errorCode variable
+				 * (malloc-ed). */
+    struct BgError *nextPtr;	/* Next in list of all pending error
+				 * reports for this interpreter, or NULL
+				 * for end of list. */
+} BgError;
+
+/*
+ * One of the structures below is associated with the "tclBgError"
+ * assoc data for each interpreter.  It keeps track of the head and
+ * tail of the list of pending background errors for the interpreter.
+ */
+
+typedef struct ErrAssocData {
+    BgError *firstBgPtr;	/* First in list of all background errors
+				 * waiting to be processed for this
+				 * interpreter (NULL if none). */
+    BgError *lastBgPtr;		/* Last in list of all background errors
+				 * waiting to be processed for this
+				 * interpreter (NULL if none). */
+} ErrAssocData;
+
+/*
+ * For each exit handler created with a call to Tcl_CreateExitHandler
+ * there is a structure of the following type:
+ */
+
+typedef struct ExitHandler {
+    Tcl_ExitProc *proc;		/* Procedure to call when process exits. */
+    ClientData clientData;	/* One word of information to pass to proc. */
+    struct ExitHandler *nextPtr;/* Next in list of all exit handlers for
+				 * this application, or NULL for end of list. */
+} ExitHandler;
+
+static ExitHandler *firstExitPtr = NULL;
+				/* First in list of all exit handlers for
+				 * application. */
+
+/*
+ * The following variable is a "secret" indication to Tcl_Exit that
+ * it should dump out the state of memory before exiting.  If the
+ * value is non-NULL, it gives the name of the file in which to
+ * dump memory usage information.
+ */
+
+char *tclMemDumpFileName = NULL;
+
+/*
+ * This variable is set to 1 when Tcl_Exit is called, and at the end of
+ * its work, it is reset to 0. The variable is checked by TclInExit() to
+ * allow different behavior for exit-time processing, e.g. in closing of
+ * files and pipes.
+ */
+
+static int tclInExit = 0;
+
+/*
+ * Prototypes for procedures referenced only in this file:
+ */
+
+static void		BgErrorDeleteProc _ANSI_ARGS_((ClientData clientData,
+			    Tcl_Interp *interp));
+static void		HandleBgErrors _ANSI_ARGS_((ClientData clientData));
+static char *		VwaitVarProc _ANSI_ARGS_((ClientData clientData,
+			    Tcl_Interp *interp, char *name1, char *name2,
+			    int flags));
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_BackgroundError --
+ *
+ *	This procedure is invoked to handle errors that occur in Tcl
+ *	commands that are invoked in "background" (e.g. from event or
+ *	timer bindings).
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The command "bgerror" is invoked later as an idle handler to
+ *	process the error, passing it the error message.  If that fails,
+ *	then an error message is output on stderr.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_BackgroundError(interp)
+    Tcl_Interp *interp;		/* Interpreter in which an error has
+				 * occurred. */
+{
+    BgError *errPtr;
+    char *errResult, *varValue;
+    ErrAssocData *assocPtr;
+
+    /*
+     * The Tcl_AddErrorInfo call below (with an empty string) ensures that
+     * errorInfo gets properly set.  It's needed in cases where the error
+     * came from a utility procedure like Tcl_GetVar instead of Tcl_Eval;
+     * in these cases errorInfo still won't have been set when this
+     * procedure is called.
+     */
+
+    Tcl_AddErrorInfo(interp, "");
+
+    errResult = TclGetStringFromObj(Tcl_GetObjResult(interp), (int *) NULL);
+	
+    errPtr = (BgError *) ckalloc(sizeof(BgError));
+    errPtr->interp = interp;
+    errPtr->errorMsg = (char *) ckalloc((unsigned) (strlen(errResult) + 1));
+    strcpy(errPtr->errorMsg, errResult);
+    varValue = Tcl_GetVar(interp, "errorInfo", TCL_GLOBAL_ONLY);
+    if (varValue == NULL) {
+	varValue = errPtr->errorMsg;
+    }
+    errPtr->errorInfo = (char *) ckalloc((unsigned) (strlen(varValue) + 1));
+    strcpy(errPtr->errorInfo, varValue);
+    varValue = Tcl_GetVar(interp, "errorCode", TCL_GLOBAL_ONLY);
+    if (varValue == NULL) {
+	varValue = "";
+    }
+    errPtr->errorCode = (char *) ckalloc((unsigned) (strlen(varValue) + 1));
+    strcpy(errPtr->errorCode, varValue);
+    errPtr->nextPtr = NULL;
+
+    assocPtr = (ErrAssocData *) Tcl_GetAssocData(interp, "tclBgError",
+	    (Tcl_InterpDeleteProc **) NULL);
+    if (assocPtr == NULL) {
+
+	/*
+	 * This is the first time a background error has occurred in
+	 * this interpreter.  Create associated data to keep track of
+	 * pending error reports.
+	 */
+
+	assocPtr = (ErrAssocData *) ckalloc(sizeof(ErrAssocData));
+	assocPtr->firstBgPtr = NULL;
+	assocPtr->lastBgPtr = NULL;
+	Tcl_SetAssocData(interp, "tclBgError", BgErrorDeleteProc,
+		(ClientData) assocPtr);
+    }
+    if (assocPtr->firstBgPtr == NULL) {
+	assocPtr->firstBgPtr = errPtr;
+	Tcl_DoWhenIdle(HandleBgErrors, (ClientData) assocPtr);
+    } else {
+	assocPtr->lastBgPtr->nextPtr = errPtr;
+    }
+    assocPtr->lastBgPtr = errPtr;
+    Tcl_ResetResult(interp);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * HandleBgErrors --
+ *
+ *	This procedure is invoked as an idle handler to process all of
+ *	the accumulated background errors.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Depends on what actions "bgerror" takes for the errors.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+HandleBgErrors(clientData)
+    ClientData clientData;	/* Pointer to ErrAssocData structure. */
+{
+    Tcl_Interp *interp;
+    char *command;
+    char *argv[2];
+    int code;
+    BgError *errPtr;
+    ErrAssocData *assocPtr = (ErrAssocData *) clientData;
+    Tcl_Channel errChannel;
+
+    Tcl_Preserve((ClientData) assocPtr);
+    
+    while (assocPtr->firstBgPtr != NULL) {
+	interp = assocPtr->firstBgPtr->interp;
+	if (interp == NULL) {
+	    goto doneWithInterp;
+	}
+
+	/*
+	 * Restore important state variables to what they were at
+	 * the time the error occurred.
+	 */
+
+	Tcl_SetVar(interp, "errorInfo", assocPtr->firstBgPtr->errorInfo,
+		TCL_GLOBAL_ONLY);
+	Tcl_SetVar(interp, "errorCode", assocPtr->firstBgPtr->errorCode,
+		TCL_GLOBAL_ONLY);
+
+	/*
+	 * Create and invoke the bgerror command.
+	 */
+
+	argv[0] = "bgerror";
+	argv[1] = assocPtr->firstBgPtr->errorMsg;
+	command = Tcl_Merge(2, argv);
+	Tcl_AllowExceptions(interp);
+        Tcl_Preserve((ClientData) interp);
+	code = Tcl_GlobalEval(interp, command);
+	ckfree(command);
+	if (code == TCL_ERROR) {
+
+            /*
+             * If the interpreter is safe, we look for a hidden command
+             * named "bgerror" and call that with the error information.
+             * Otherwise, simply ignore the error. The rationale is that
+             * this could be an error caused by a malicious applet trying
+             * to cause an infinite barrage of error messages. The hidden
+             * "bgerror" command can be used by a security policy to
+             * interpose on such attacks and e.g. kill the applet after a
+             * few attempts.
+             */
+
+            if (Tcl_IsSafe(interp)) {
+                Tcl_HashTable *hTblPtr;
+                Tcl_HashEntry *hPtr;
+
+                hTblPtr = (Tcl_HashTable *) Tcl_GetAssocData(interp,
+                        "tclHiddenCmds", NULL);
+                if (hTblPtr == (Tcl_HashTable *) NULL) {
+                    goto doneWithInterp;
+                }
+                hPtr = Tcl_FindHashEntry(hTblPtr, "bgerror");
+                if (hPtr == (Tcl_HashEntry *) NULL) {
+                    goto doneWithInterp;
+                }
+
+                /*
+                 * OK, the hidden command "bgerror" exists, invoke it.
+                 */
+
+                argv[0] = "bgerror";
+                argv[1] = ckalloc((unsigned)
+                        strlen(assocPtr->firstBgPtr->errorMsg));
+                strcpy(argv[1], assocPtr->firstBgPtr->errorMsg);
+                (void) TclInvoke(interp, 2, argv, TCL_INVOKE_HIDDEN);
+                ckfree(argv[1]);
+
+                goto doneWithInterp;
+            } 
+
+            /*
+             * We have to get the error output channel at the latest possible
+             * time, because the eval (above) might have changed the channel.
+             */
+            
+            errChannel = Tcl_GetStdChannel(TCL_STDERR);
+            if (errChannel != (Tcl_Channel) NULL) {
+                if (strcmp(interp->result,
+           "\"bgerror\" is an invalid command name or ambiguous abbreviation")
+                        == 0) {
+                    Tcl_Write(errChannel, assocPtr->firstBgPtr->errorInfo, -1);
+                    Tcl_Write(errChannel, "\n", -1);
+                } else {
+                    Tcl_Write(errChannel,
+                            "bgerror failed to handle background error.\n",
+                            -1);
+                    Tcl_Write(errChannel, "    Original error: ", -1);
+                    Tcl_Write(errChannel, assocPtr->firstBgPtr->errorMsg,
+                            -1);
+                    Tcl_Write(errChannel, "\n", -1);
+                    Tcl_Write(errChannel, "    Error in bgerror: ", -1);
+                    Tcl_Write(errChannel, interp->result, -1);
+                    Tcl_Write(errChannel, "\n", -1);
+                }
+                Tcl_Flush(errChannel);
+            }
+	} else if (code == TCL_BREAK) {
+
+	    /*
+	     * Break means cancel any remaining error reports for this
+	     * interpreter.
+	     */
+
+	    for (errPtr = assocPtr->firstBgPtr; errPtr != NULL;
+		    errPtr = errPtr->nextPtr) {
+		if (errPtr->interp == interp) {
+		    errPtr->interp = NULL;
+		}
+	    }
+	}
+
+	/*
+	 * Discard the command and the information about the error report.
+	 */
+
+doneWithInterp:
+
+	if (assocPtr->firstBgPtr) {
+	    ckfree(assocPtr->firstBgPtr->errorMsg);
+	    ckfree(assocPtr->firstBgPtr->errorInfo);
+	    ckfree(assocPtr->firstBgPtr->errorCode);
+	    errPtr = assocPtr->firstBgPtr->nextPtr;
+	    ckfree((char *) assocPtr->firstBgPtr);
+	    assocPtr->firstBgPtr = errPtr;
+	}
+        
+        if (interp != NULL) {
+            Tcl_Release((ClientData) interp);
+        }
+    }
+    assocPtr->lastBgPtr = NULL;
+
+    Tcl_Release((ClientData) assocPtr);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * BgErrorDeleteProc --
+ *
+ *	This procedure is associated with the "tclBgError" assoc data
+ *	for an interpreter;  it is invoked when the interpreter is
+ *	deleted in order to free the information assoicated with any
+ *	pending error reports.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Background error information is freed: if there were any
+ *	pending error reports, they are cancelled.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+BgErrorDeleteProc(clientData, interp)
+    ClientData clientData;	/* Pointer to ErrAssocData structure. */
+    Tcl_Interp *interp;		/* Interpreter being deleted. */
+{
+    ErrAssocData *assocPtr = (ErrAssocData *) clientData;
+    BgError *errPtr;
+
+    while (assocPtr->firstBgPtr != NULL) {
+	errPtr = assocPtr->firstBgPtr;
+	assocPtr->firstBgPtr = errPtr->nextPtr;
+	ckfree(errPtr->errorMsg);
+	ckfree(errPtr->errorInfo);
+	ckfree(errPtr->errorCode);
+	ckfree((char *) errPtr);
+    }
+    Tcl_CancelIdleCall(HandleBgErrors, (ClientData) assocPtr);
+    Tcl_EventuallyFree((ClientData) assocPtr, TCL_DYNAMIC);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_CreateExitHandler --
+ *
+ *	Arrange for a given procedure to be invoked just before the
+ *	application exits.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Proc will be invoked with clientData as argument when the
+ *	application exits.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_CreateExitHandler(proc, clientData)
+    Tcl_ExitProc *proc;		/* Procedure to invoke. */
+    ClientData clientData;	/* Arbitrary value to pass to proc. */
+{
+    ExitHandler *exitPtr;
+
+    exitPtr = (ExitHandler *) ckalloc(sizeof(ExitHandler));
+    exitPtr->proc = proc;
+    exitPtr->clientData = clientData;
+    exitPtr->nextPtr = firstExitPtr;
+    firstExitPtr = exitPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_DeleteExitHandler --
+ *
+ *	This procedure cancels an existing exit handler matching proc
+ *	and clientData, if such a handler exits.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	If there is an exit handler corresponding to proc and clientData
+ *	then it is cancelled;  if no such handler exists then nothing
+ *	happens.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_DeleteExitHandler(proc, clientData)
+    Tcl_ExitProc *proc;		/* Procedure that was previously registered. */
+    ClientData clientData;	/* Arbitrary value to pass to proc. */
+{
+    ExitHandler *exitPtr, *prevPtr;
+
+    for (prevPtr = NULL, exitPtr = firstExitPtr; exitPtr != NULL;
+	    prevPtr = exitPtr, exitPtr = exitPtr->nextPtr) {
+	if ((exitPtr->proc == proc)
+		&& (exitPtr->clientData == clientData)) {
+	    if (prevPtr == NULL) {
+		firstExitPtr = exitPtr->nextPtr;
+	    } else {
+		prevPtr->nextPtr = exitPtr->nextPtr;
+	    }
+	    ckfree((char *) exitPtr);
+	    return;
+	}
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_Exit --
+ *
+ *	This procedure is called to terminate the application.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	All existing exit handlers are invoked, then the application
+ *	ends.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_Exit(status)
+    int status;			/* Exit status for application;  typically
+				 * 0 for normal return, 1 for error return. */
+{
+    Tcl_Finalize();
+#ifdef TCL_MEM_DEBUG
+    if (tclMemDumpFileName != NULL) {
+	Tcl_DumpActiveMemory(tclMemDumpFileName);
+    }
+#endif
+    TclPlatformExit(status);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_Finalize --
+ *
+ *	Runs the exit handlers to allow Tcl to clean up its state prior
+ *	to being unloaded. Called by Tcl_Exit and when Tcl was dynamically
+ *	loaded and is now being unloaded.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Whatever the exit handlers do. Also frees up storage associated
+ *	with the Tcl object type table.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_Finalize()
+{
+    ExitHandler *exitPtr;
+    
+    /*
+     * Invoke exit handler first.
+     */
+
+    tclInExit = 1;
+    for (exitPtr = firstExitPtr; exitPtr != NULL; exitPtr = firstExitPtr) {
+	/*
+	 * Be careful to remove the handler from the list before invoking
+	 * its callback.  This protects us against double-freeing if the
+	 * callback should call Tcl_DeleteExitHandler on itself.
+	 */
+
+	firstExitPtr = exitPtr->nextPtr;
+	(*exitPtr->proc)(exitPtr->clientData);
+	ckfree((char *) exitPtr);
+    }
+
+    /*
+     * Now finalize the Tcl execution environment.  Note that this must be done
+     * after the exit handlers, because there are order dependencies.
+     */
+    
+    TclFinalizeCompExecEnv();
+    TclFinalizeEnvironment();
+    firstExitPtr = NULL;
+    tclInExit = 0;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TclInExit --
+ *
+ *	Determines if we are in the middle of exit-time cleanup.
+ *
+ * Results:
+ *	If we are in the middle of exiting, 1, otherwise 0.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+TclInExit()
+{
+    return tclInExit;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_VwaitCmd --
+ *
+ *	This procedure is invoked to process the "vwait" Tcl command.
+ *	See the user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+	/* ARGSUSED */
+int
+Tcl_VwaitCmd(clientData, interp, argc, argv)
+    ClientData clientData;	/* Not used. */
+    Tcl_Interp *interp;		/* Current interpreter. */
+    int argc;			/* Number of arguments. */
+    char **argv;		/* Argument strings. */
+{
+    int done, foundEvent;
+
+    if (argc != 2) {
+	Tcl_AppendResult(interp, "wrong # args: should be \"",
+		argv[0], " name\"", (char *) NULL);
+	return TCL_ERROR;
+    }
+    if (Tcl_TraceVar(interp, argv[1],
+	    TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
+	    VwaitVarProc, (ClientData) &done) != TCL_OK) {
+	return TCL_ERROR;
+    };
+    done = 0;
+    foundEvent = 1;
+    while (!done && foundEvent) {
+	foundEvent = Tcl_DoOneEvent(TCL_ALL_EVENTS);
+    }
+    Tcl_UntraceVar(interp, argv[1],
+	    TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
+	    VwaitVarProc, (ClientData) &done);
+
+    /*
+     * Clear out the interpreter's result, since it may have been set
+     * by event handlers.
+     */
+
+    Tcl_ResetResult(interp);
+    if (!foundEvent) {
+	Tcl_AppendResult(interp, "can't wait for variable \"", argv[1],
+		"\":  would wait forever", (char *) NULL);
+	return TCL_ERROR;
+    }
+    return TCL_OK;
+}
+
+	/* ARGSUSED */
+static char *
+VwaitVarProc(clientData, interp, name1, name2, flags)
+    ClientData clientData;	/* Pointer to integer to set to 1. */
+    Tcl_Interp *interp;		/* Interpreter containing variable. */
+    char *name1;		/* Name of variable. */
+    char *name2;		/* Second part of variable name. */
+    int flags;			/* Information about what happened. */
+{
+    int *donePtr = (int *) clientData;
+
+    *donePtr = 1;
+    return (char *) NULL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_UpdateCmd --
+ *
+ *	This procedure is invoked to process the "update" Tcl command.
+ *	See the user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *----------------------------------------------------------------------
+ */
+
+	/* ARGSUSED */
+int
+Tcl_UpdateCmd(clientData, interp, argc, argv)
+    ClientData clientData;	/* Not used. */
+    Tcl_Interp *interp;		/* Current interpreter. */
+    int argc;			/* Number of arguments. */
+    char **argv;		/* Argument strings. */
+{
+    int flags;
+
+    if (argc == 1) {
+	flags = TCL_ALL_EVENTS|TCL_DONT_WAIT;
+    } else if (argc == 2) {
+	if (strncmp(argv[1], "idletasks", strlen(argv[1])) != 0) {
+	    Tcl_AppendResult(interp, "bad option \"", argv[1],
+		    "\": must be idletasks", (char *) NULL);
+	    return TCL_ERROR;
+	}
+	flags = TCL_WINDOW_EVENTS|TCL_IDLE_EVENTS|TCL_DONT_WAIT;
+    } else {
+	Tcl_AppendResult(interp, "wrong # args: should be \"",
+		argv[0], " ?idletasks?\"", (char *) NULL);
+	return TCL_ERROR;
+    }
+
+    while (Tcl_DoOneEvent(flags) != 0) {
+	/* Empty loop body */
+    }
+
+    /*
+     * Must clear the interpreter's result because event handlers could
+     * have executed commands.
+     */
+
+    Tcl_ResetResult(interp);
+    return TCL_OK;
+}