tclthreadtest.c

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/* 
 * tclThreadTest.c --
 *
 *	This file implements the testthread command.  Eventually this
 *	should be tclThreadCmd.c
 *	Some of this code is based on work done by Richard Hipp on behalf of
 *	Conservation Through Innovation, Limited, with their permission.
 *
 * Copyright (c) 1998 by 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: tclThreadTest.c,v 1.16 2002/01/26 01:10:08 dgp Exp $
 */

#include "tclInt.h"

#ifdef TCL_THREADS
/*
 * Each thread has an single instance of the following structure.  There
 * is one instance of this structure per thread even if that thread contains
 * multiple interpreters.  The interpreter identified by this structure is
 * the main interpreter for the thread.  
 *
 * The main interpreter is the one that will process any messages 
 * received by a thread.  Any thread can send messages but only the
 * main interpreter can receive them.
 */

typedef struct ThreadSpecificData {
    Tcl_ThreadId  threadId;          /* Tcl ID for this thread */
    Tcl_Interp *interp;              /* Main interpreter for this thread */
    int flags;                       /* See the TP_ defines below... */
    struct ThreadSpecificData *nextPtr;	/* List for "thread names" */
    struct ThreadSpecificData *prevPtr;	/* List for "thread names" */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;

/*
 * This list is used to list all threads that have interpreters.
 * This is protected by threadMutex.
 */

static struct ThreadSpecificData *threadList;

/*
 * The following bit-values are legal for the "flags" field of the
 * ThreadSpecificData structure.
 */
#define TP_Dying               0x001 /* This thread is being cancelled */

/*
 * An instance of the following structure contains all information that is
 * passed into a new thread when the thread is created using either the
 * "thread create" Tcl command or the TclCreateThread() C function.
 */

typedef struct ThreadCtrl {
    char *script;    /* The TCL command this thread should execute */
    int flags;        /* Initial value of the "flags" field in the 
                       * ThreadSpecificData structure for the new thread.
                       * Might contain TP_Detached or TP_TclThread. */
    Tcl_Condition condWait;
    /* This condition variable is used to synchronize
     * the parent and child threads.  The child won't run
     * until it acquires threadMutex, and the parent function
     * won't complete until signaled on this condition
     * variable. */
} ThreadCtrl;

/*
 * This is the event used to send scripts to other threads.
 */

typedef struct ThreadEvent {
    Tcl_Event event;		/* Must be first */
    char *script;		/* The script to execute. */
    struct ThreadEventResult *resultPtr;
				/* To communicate the result.  This is
				 * NULL if we don't care about it. */
} ThreadEvent;

typedef struct ThreadEventResult {
    Tcl_Condition done;		/* Signaled when the script completes */
    int code;			/* Return value of Tcl_Eval */
    char *result;		/* Result from the script */
    char *errorInfo;		/* Copy of errorInfo variable */
    char *errorCode;		/* Copy of errorCode variable */
    Tcl_ThreadId srcThreadId;	/* Id of sending thread, in case it dies */
    Tcl_ThreadId dstThreadId;	/* Id of target thread, in case it dies */
    struct ThreadEvent *eventPtr;	/* Back pointer */
    struct ThreadEventResult *nextPtr;	/* List for cleanup */
    struct ThreadEventResult *prevPtr;

} ThreadEventResult;

static ThreadEventResult *resultList;

/*
 * This is for simple error handling when a thread script exits badly.
 */

static Tcl_ThreadId errorThreadId;
static char *errorProcString;

/* 
 * Access to the list of threads and to the thread send results is
 * guarded by this mutex. 
 */

TCL_DECLARE_MUTEX(threadMutex)

#undef TCL_STORAGE_CLASS
#define TCL_STORAGE_CLASS DLLEXPORT

EXTERN int	TclThread_Init _ANSI_ARGS_((Tcl_Interp *interp));
EXTERN int	Tcl_ThreadObjCmd _ANSI_ARGS_((ClientData clientData,
	Tcl_Interp *interp, int objc, Tcl_Obj *CONST objv[]));
EXTERN int	TclCreateThread _ANSI_ARGS_((Tcl_Interp *interp,
	char *script, int joinable));
EXTERN int	TclThreadList _ANSI_ARGS_((Tcl_Interp *interp));
EXTERN int	TclThreadSend _ANSI_ARGS_((Tcl_Interp *interp, Tcl_ThreadId id,
	char *script, int wait));

#undef TCL_STORAGE_CLASS
#define TCL_STORAGE_CLASS DLLIMPORT

Tcl_ThreadCreateType	NewTestThread _ANSI_ARGS_((ClientData clientData));
static void	ListRemove _ANSI_ARGS_((ThreadSpecificData *tsdPtr));
static void	ListUpdateInner _ANSI_ARGS_((ThreadSpecificData *tsdPtr));
static int	ThreadEventProc _ANSI_ARGS_((Tcl_Event *evPtr, int mask));
static void	ThreadErrorProc _ANSI_ARGS_((Tcl_Interp *interp));
static void	ThreadFreeProc _ANSI_ARGS_((ClientData clientData));
static int	ThreadDeleteEvent _ANSI_ARGS_((Tcl_Event *eventPtr,
	ClientData clientData));
static void	ThreadExitProc _ANSI_ARGS_((ClientData clientData));


/*
 *----------------------------------------------------------------------
 *
 * TclThread_Init --
 *
 *	Initialize the test thread command.
 *
 * Results:
 *      TCL_OK if the package was properly initialized.
 *
 * Side effects:
 *	Add the "testthread" command to the interp.
 *
 *----------------------------------------------------------------------
 */

int
TclThread_Init(interp)
    Tcl_Interp *interp; /* The current Tcl interpreter */
{
    
    Tcl_CreateObjCommand(interp,"testthread", Tcl_ThreadObjCmd, 
	    (ClientData)NULL ,NULL);
    if (Tcl_PkgProvide(interp, "Thread", "1.0" ) != TCL_OK) {
	return TCL_ERROR;
    }
    return TCL_OK;
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_ThreadObjCmd --
 *
 *	This procedure is invoked to process the "testthread" Tcl command.
 *	See the user documentation for details on what it does.
 *
 *	thread create ?-joinable? ?script?
 *	thread send id ?-async? script
 *	thread exit
 *	thread info id
 *	thread names
 *	thread wait
 *	thread errorproc proc
 *	thread join id
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
int
Tcl_ThreadObjCmd(dummy, interp, objc, objv)
    ClientData dummy;			/* Not used. */
    Tcl_Interp *interp;			/* Current interpreter. */
    int objc;				/* Number of arguments. */
    Tcl_Obj *CONST objv[];		/* Argument objects. */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    int option;
    static CONST char *threadOptions[] = {"create", "exit", "id", "join", "names",
				    "send", "wait", "errorproc",
				    (char *) NULL};
    enum options {THREAD_CREATE, THREAD_EXIT, THREAD_ID, THREAD_JOIN,
		  THREAD_NAMES, THREAD_SEND, THREAD_WAIT, THREAD_ERRORPROC};

    if (objc < 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "option ?args?");
	return TCL_ERROR;
    }
    if (Tcl_GetIndexFromObj(interp, objv[1], threadOptions,
	    "option", 0, &option) != TCL_OK) {
	return TCL_ERROR;
    }

    /* 
     * Make sure the initial thread is on the list before doing anything.
     */

    if (tsdPtr->interp == NULL) {
	Tcl_MutexLock(&threadMutex);
	tsdPtr->interp = interp;
	ListUpdateInner(tsdPtr);
	Tcl_CreateThreadExitHandler(ThreadExitProc, NULL);
	Tcl_MutexUnlock(&threadMutex);
    }

    switch ((enum options)option) {
	case THREAD_CREATE: {
	    char *script;
	    int   joinable, len;

	    if (objc == 2) {
	        /* Neither joinable nor special script
		 */

	        joinable = 0;
		script   = "testthread wait";	/* Just enter the event loop */

	    } else if (objc == 3) {
	        /* Possibly -joinable, then no special script,
		 * no joinable, then its a script.
		 */

	        script = Tcl_GetString(objv[2]);
		len    = strlen (script);

		if ((len > 1) &&
		    (script [0] == '-') && (script [1] == 'j') &&
		    (0 == strncmp (script, "-joinable", (size_t) len))) {
		    joinable = 1;
		    script   = "testthread wait"; /* Just enter the event loop
						   */
		} else {
		    /* Remember the script */
		    joinable = 0;
		}
	    } else if (objc == 4) {
	        /* Definitely a script available, but is the flag
		 * -joinable ?
		 */

	        script = Tcl_GetString(objv[2]);
		len    = strlen (script);

		joinable = ((len > 1) &&
			    (script [0] == '-') && (script [1] == 'j') &&
			    (0 == strncmp (script, "-joinable", (size_t) len)));

		script = Tcl_GetString(objv[3]);
	    } else {
		Tcl_WrongNumArgs(interp, 2, objv, "?-joinable? ?script?");
		return TCL_ERROR;
	    }
	    return TclCreateThread(interp, script, joinable);
	}
	case THREAD_EXIT: {
	    if (objc > 2) {
		Tcl_WrongNumArgs(interp, 1, objv, NULL);
		return TCL_ERROR;
	    }
	    ListRemove(NULL);
	    Tcl_ExitThread(0);
	    return TCL_OK;
	}
	case THREAD_ID:
	    if (objc == 2) {
		Tcl_Obj *idObj = Tcl_NewLongObj((long)Tcl_GetCurrentThread());
		Tcl_SetObjResult(interp, idObj);
		return TCL_OK;
	    } else {
		Tcl_WrongNumArgs(interp, 2, objv, NULL);
		return TCL_ERROR;
	    }
        case THREAD_JOIN: {
	    long id;
	    int result, status;

	    if (objc != 3) {
		Tcl_WrongNumArgs(interp, 1, objv, "join id");
		return TCL_ERROR;
	    }
	    if (Tcl_GetLongFromObj(interp, objv[2], &id) != TCL_OK) {
		return TCL_ERROR;
	    }

	    result = Tcl_JoinThread ((Tcl_ThreadId) id, &status);
	    if (result == TCL_OK) {
	        Tcl_SetIntObj (Tcl_GetObjResult (interp), status);
	    } else {
	        char buf [20];
		sprintf (buf, "%ld", id);
		Tcl_AppendResult (interp, "cannot join thread ", buf, NULL);
	    }
	    return result;
	}
	case THREAD_NAMES: {
	    if (objc > 2) {
		Tcl_WrongNumArgs(interp, 2, objv, NULL);
		return TCL_ERROR;
	    }
	    return TclThreadList(interp);
	}
	case THREAD_SEND: {
	    long id;
	    char *script;
	    int wait, arg;

	    if ((objc != 4) && (objc != 5)) {
		Tcl_WrongNumArgs(interp, 1, objv, "send ?-async? id script");
		return TCL_ERROR;
	    }
	    if (objc == 5) {
		if (strcmp("-async", Tcl_GetString(objv[2])) != 0) {
		    Tcl_WrongNumArgs(interp, 1, objv, "send ?-async? id script");
		    return TCL_ERROR;
		}
		wait = 0;
		arg = 3;
	    } else {
		wait = 1;
		arg = 2;
	    }
	    if (Tcl_GetLongFromObj(interp, objv[arg], &id) != TCL_OK) {
		return TCL_ERROR;
	    }
	    arg++;
	    script = Tcl_GetString(objv[arg]);
	    return TclThreadSend(interp, (Tcl_ThreadId) id, script, wait);
	}
	case THREAD_WAIT: {
	    while (1) {
		(void) Tcl_DoOneEvent(TCL_ALL_EVENTS);
	    }
	}
	case THREAD_ERRORPROC: {
	    /*
	     * Arrange for this proc to handle thread death errors.
	     */

	    char *proc;
	    if (objc != 3) {
		Tcl_WrongNumArgs(interp, 1, objv, "errorproc proc");
		return TCL_ERROR;
	    }
	    Tcl_MutexLock(&threadMutex);
	    errorThreadId = Tcl_GetCurrentThread();
	    if (errorProcString) {
		ckfree(errorProcString);
	    }
	    proc = Tcl_GetString(objv[2]);
	    errorProcString = ckalloc(strlen(proc)+1);
	    strcpy(errorProcString, proc);
	    Tcl_MutexUnlock(&threadMutex);
	    return TCL_OK;
	}
    }
    return TCL_OK;
}


/*
 *----------------------------------------------------------------------
 *
 * TclCreateThread --
 *
 *	This procedure is invoked to create a thread containing an interp to
 *	run a script.  This returns after the thread has started executing.
 *
 * Results:
 *	A standard Tcl result, which is the thread ID.
 *
 * Side effects:
 *	Create a thread.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
int
TclCreateThread(interp, script, joinable)
    Tcl_Interp *interp;			/* Current interpreter. */
    char *script;			/* Script to execute */
    int         joinable;		/* Flag, joinable thread or not */
{
    ThreadCtrl ctrl;
    Tcl_ThreadId id;

    ctrl.script = script;
    ctrl.condWait = NULL;
    ctrl.flags = 0;

    joinable = joinable ? TCL_THREAD_JOINABLE : TCL_THREAD_NOFLAGS;

    Tcl_MutexLock(&threadMutex);
    if (Tcl_CreateThread(&id, NewTestThread, (ClientData) &ctrl,
		 TCL_THREAD_STACK_DEFAULT, joinable) != TCL_OK) {
	Tcl_MutexUnlock(&threadMutex);
        Tcl_AppendResult(interp,"can't create a new thread",0);
	ckfree((void*)ctrl.script);
	return TCL_ERROR;
    }

    /*
     * Wait for the thread to start because it is using something on our stack!
     */

    Tcl_ConditionWait(&ctrl.condWait, &threadMutex, NULL);
    Tcl_MutexUnlock(&threadMutex);
    Tcl_ConditionFinalize(&ctrl.condWait);
    Tcl_SetObjResult(interp, Tcl_NewLongObj((long)id));
    return TCL_OK;
}

/*
 *------------------------------------------------------------------------
 *
 * NewTestThread --
 *
 *    This routine is the "main()" for a new thread whose task is to
 *    execute a single TCL script.  The argument to this function is
 *    a pointer to a structure that contains the text of the TCL script
 *    to be executed.
 *
 *    Space to hold the script field of the ThreadControl structure passed 
 *    in as the only argument was obtained from malloc() and must be freed 
 *    by this function before it exits.  Space to hold the ThreadControl
 *    structure itself is released by the calling function, and the
 *    two condition variables in the ThreadControl structure are destroyed
 *    by the calling function.  The calling function will destroy the
 *    ThreadControl structure and the condition variable as soon as
 *    ctrlPtr->condWait is signaled, so this routine must make copies of
 *    any data it might need after that point.
 *
 * Results:
 *    none
 *
 * Side effects:
 *    A TCL script is executed in a new thread.
 *
 *------------------------------------------------------------------------
 */
Tcl_ThreadCreateType
NewTestThread(clientData)
    ClientData clientData;
{
    ThreadCtrl *ctrlPtr = (ThreadCtrl*)clientData;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    int result;
    char *threadEvalScript;

    /*
     * Initialize the interpreter.  This should be more general.
     */

    tsdPtr->interp = Tcl_CreateInterp();
    result = Tcl_Init(tsdPtr->interp);
    result = TclThread_Init(tsdPtr->interp);

    /*
     * Update the list of threads.
     */

    Tcl_MutexLock(&threadMutex);
    ListUpdateInner(tsdPtr);
    /*
     * We need to keep a pointer to the alloc'ed mem of the script
     * we are eval'ing, for the case that we exit during evaluation
     */
    threadEvalScript = (char *) ckalloc(strlen(ctrlPtr->script)+1);
    strcpy(threadEvalScript, ctrlPtr->script);

    Tcl_CreateThreadExitHandler(ThreadExitProc, (ClientData) threadEvalScript);

    /*
     * Notify the parent we are alive.
     */

    Tcl_ConditionNotify(&ctrlPtr->condWait);
    Tcl_MutexUnlock(&threadMutex);

    /*
     * Run the script.
     */

    Tcl_Preserve((ClientData) tsdPtr->interp);
    result = Tcl_Eval(tsdPtr->interp, threadEvalScript);
    if (result != TCL_OK) {
	ThreadErrorProc(tsdPtr->interp);
    }