/*
 * tclLoad.c --
 *
 *	This file provides the generic portion (those that are the same on all
 *	platforms) of Tcl's dynamic loading facilities.
 *
 * Copyright (c) 1995-1997 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: tclLoad.c,v 1.16 2007/02/20 23:24:03 nijtmans Exp $
 */

#include "tclInt.h"

/*
 * The following structure describes a package that has been loaded either
 * dynamically (with the "load" command) or statically (as indicated by a call

    /*
     * Scan through the list of packages already loaded in the target
     * interpreter. If the package we want is already loaded there, then
     * there's nothing for us to do.
     */

    if (pkgPtr != NULL) {
	ipFirstPtr = (InterpPackage *) Tcl_GetAssocData(target,
		"tclLoad", NULL);
	for (ipPtr = ipFirstPtr; ipPtr != NULL; ipPtr = ipPtr->nextPtr) {
	    if (ipPtr->pkgPtr == pkgPtr) {
		code = TCL_OK;
		goto done;
	    }
	}
    }

	procPtrs[2] = &unloadProc;
	procPtrs[3] = &safeUnloadProc;

	Tcl_MutexLock(&packageMutex);
	code = TclLoadFile(interp, objv[1], 4, symbols, procPtrs,
		&loadHandle, &clientData, &unLoadProcPtr);
	Tcl_MutexUnlock(&packageMutex);
	loadHandle = (Tcl_LoadHandle) clientData;
	if (code != TCL_OK) {
	    goto done;
	}

	if (*procPtrs[0] /* initProc */ == NULL) {
	    Tcl_AppendResult(interp, "couldn't find procedure ",
		    Tcl_DStringValue(&initName), NULL);
	    if (unLoadProcPtr != NULL) {
		(*unLoadProcPtr)(loadHandle);
	    }
	    code = TCL_ERROR;
	    goto done;
	}

	/*
	 * Create a new record to describe this package.
	 */

	pkgPtr = (LoadedPackage *) ckalloc(sizeof(LoadedPackage));
	pkgPtr->fileName	   = (char *) ckalloc((unsigned)
		(strlen(fullFileName) + 1));
	strcpy(pkgPtr->fileName, fullFileName);
	pkgPtr->packageName	   = (char *) ckalloc((unsigned)
		(Tcl_DStringLength(&pkgName) + 1));
	strcpy(pkgPtr->packageName, Tcl_DStringValue(&pkgName));
	pkgPtr->loadHandle	   = loadHandle;
	pkgPtr->unLoadProcPtr	   = unLoadProcPtr;
	pkgPtr->initProc	   = *procPtrs[0];
	pkgPtr->safeInitProc	   = *procPtrs[1];
	pkgPtr->unloadProc	   = (Tcl_PackageUnloadProc*) *procPtrs[2];
	pkgPtr->safeUnloadProc	   = (Tcl_PackageUnloadProc*) *procPtrs[3];
	pkgPtr->interpRefCount	   = 0;
	pkgPtr->safeInterpRefCount = 0;

	Tcl_MutexLock(&packageMutex);
	pkgPtr->nextPtr		   = firstPackagePtr;
	firstPackagePtr		   = pkgPtr;
	Tcl_MutexUnlock(&packageMutex);
    }

    /*
     * Invoke the package's initialization function (either the normal one or
     * the safe one, depending on whether or not the interpreter is safe).
     */

    if (Tcl_IsSafe(target)) {
	if (pkgPtr->safeInitProc != NULL) {
	    code = (*pkgPtr->safeInitProc)(target);
	} else {
	    Tcl_AppendResult(interp,
		    "can't use package in a safe interpreter: no ",
		    pkgPtr->packageName, "_SafeInit procedure", NULL);
	    code = TCL_ERROR;
	    goto done;
	}
    } else {
	code = (*pkgPtr->initProc)(target);
    }

    /*
     * Record the fact that the package has been loaded in the target
     * interpreter.
     */

	Tcl_MutexUnlock(&packageMutex);

	/*
	 * Refetch ipFirstPtr: loading the package may have introduced
	 * additional static packages at the head of the linked list!
	 */

	ipFirstPtr = (InterpPackage *) Tcl_GetAssocData(target,
		"tclLoad", NULL);
	ipPtr = (InterpPackage *) ckalloc(sizeof(InterpPackage));
	ipPtr->pkgPtr = pkgPtr;
	ipPtr->nextPtr = ipFirstPtr;
	Tcl_SetAssocData(target, "tclLoad", LoadCleanupProc,
		(ClientData) ipPtr);
    } else {
	TclTransferResult(target, code, interp);
    }

  done:
    Tcl_DStringFree(&pkgName);
    Tcl_DStringFree(&initName);

    /*
     * Figure out which interpreter we're going to load the package into.
     */

    target = interp;
    if (objc - i == 3) {
	char *slaveIntName;
	slaveIntName = Tcl_GetString(objv[i+2]);
	target = Tcl_GetSlave(interp, slaveIntName);
	if (target == NULL) {
	    return TCL_ERROR;
	}
    }

    /*

     * Scan through the list of packages already loaded in the target
     * interpreter. If the package we want is already loaded there, then we
     * should proceed with unloading.
     */

    code = TCL_ERROR;
    if (pkgPtr != NULL) {
	ipFirstPtr = (InterpPackage *) Tcl_GetAssocData(target,
		"tclLoad", NULL);
	for (ipPtr = ipFirstPtr; ipPtr != NULL; ipPtr = ipPtr->nextPtr) {
	    if (ipPtr->pkgPtr == pkgPtr) {
		code = TCL_OK;
		break;
	    }
	}
    }

	    --trustedRefCount;
	}

	if (safeRefCount <= 0 && trustedRefCount <= 0) {
	    code = TCL_UNLOAD_DETACH_FROM_PROCESS;
	}
    }
    code = (*unloadProc)(target, code);
    if (code != TCL_OK) {
	TclTransferResult(target, code, interp);
	goto done;
    }

    /*
     * The unload function executed fine. Examine the reference count to see

	 */

	if (pkgPtr->fileName[0] != '\0') {
	    Tcl_FSUnloadFileProc *unLoadProcPtr = pkgPtr->unLoadProcPtr;

	    if (unLoadProcPtr != NULL) {
		Tcl_MutexLock(&packageMutex);
		(*unLoadProcPtr)(pkgPtr->loadHandle);

		/*
		 * Remove this library from the loaded library cache.
		 */

		defaultPtr = pkgPtr;
		if (defaultPtr == firstPackagePtr) {

		    }
		}

		/*
		 * Remove this library from the interpreter's library cache.
		 */

		ipFirstPtr = (InterpPackage *) Tcl_GetAssocData(target,
			"tclLoad", NULL);
		ipPtr = ipFirstPtr;
		if (ipPtr->pkgPtr == defaultPtr) {
		    ipFirstPtr = ipFirstPtr->nextPtr;
		} else {
		    InterpPackage *ipPrevPtr;

		    for (ipPrevPtr = ipPtr; ipPtr != NULL;
			    ipPrevPtr = ipPtr, ipPtr = ipPtr->nextPtr) {
			if (ipPtr->pkgPtr == pkgPtr) {
			    ipPrevPtr->nextPtr = ipPtr->nextPtr;
			    break;
			}
		    }
		}
		Tcl_SetAssocData(target, "tclLoad", LoadCleanupProc,
			(ClientData) ipFirstPtr);
		ckfree(defaultPtr->fileName);
		ckfree(defaultPtr->packageName);
		ckfree((char *) defaultPtr);
		ckfree((char *) ipPtr);
		Tcl_MutexUnlock(&packageMutex);
	    } else {
		Tcl_AppendResult(interp, "file \"", fullFileName,

    Tcl_MutexUnlock(&packageMutex);

    /*
     * If the package is not yet recorded as being loaded statically, add it
     * to the list now.
     */

    if ( pkgPtr == NULL ) {
	pkgPtr = (LoadedPackage *) ckalloc(sizeof(LoadedPackage));
	pkgPtr->fileName	= (char *) ckalloc((unsigned) 1);
	pkgPtr->fileName[0]	= 0;
	pkgPtr->packageName	= (char *)
		ckalloc((unsigned) (strlen(pkgName) + 1));
	strcpy(pkgPtr->packageName, pkgName);
	pkgPtr->loadHandle	= NULL;
	pkgPtr->initProc	= initProc;
	pkgPtr->safeInitProc	= safeInitProc;
	Tcl_MutexLock(&packageMutex);
	pkgPtr->nextPtr		= firstPackagePtr;
	firstPackagePtr		= pkgPtr;
	Tcl_MutexUnlock(&packageMutex);
    }

    if (interp != NULL) {

	/*
	 * If we're loading the package into an interpreter, determine whether
	 * it's already loaded.
	 */

	ipFirstPtr = (InterpPackage *) Tcl_GetAssocData(interp,
		"tclLoad", NULL);
	for ( ipPtr = ipFirstPtr; ipPtr != NULL; ipPtr = ipPtr->nextPtr ) {
	    if ( ipPtr->pkgPtr == pkgPtr ) {
		return;
	    }
	}

	/*
	 * Package isn't loade in the current interp yet. Mark it as now being
	 * loaded.
	 */

	ipPtr = (InterpPackage *) ckalloc(sizeof(InterpPackage));
	ipPtr->pkgPtr = pkgPtr;
	ipPtr->nextPtr = ipFirstPtr;
	Tcl_SetAssocData(interp, "tclLoad", LoadCleanupProc,
		(ClientData) ipPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetLoadedPackages --

    Tcl_Interp *interp,		/* Interpreter in which to return information
				 * or error message. */
    char *targetName)		/* Name of target interpreter or NULL. If
				 * NULL, return info about all interps;
				 * otherwise, just return info about this
				 * interpreter. */
{

    Tcl_Interp *target;
    LoadedPackage *pkgPtr;
    InterpPackage *ipPtr;
    const char *prefix;

    if (targetName == NULL) {
	/*

     * interpreter.
     */

    target = Tcl_GetSlave(interp, targetName);
    if (target == NULL) {
	return TCL_ERROR;
    }
    ipPtr = (InterpPackage *) Tcl_GetAssocData(target, "tclLoad", NULL);
    prefix = "{";
    for ( ; ipPtr != NULL; ipPtr = ipPtr->nextPtr) {
	pkgPtr = ipPtr->pkgPtr;
	Tcl_AppendResult(interp, prefix, NULL);
	Tcl_AppendElement(interp, pkgPtr->fileName);
	Tcl_AppendElement(interp, pkgPtr->packageName);
	Tcl_AppendResult(interp, "}", NULL);
	prefix = " {";
    }

LoadCleanupProc(
    ClientData clientData,	/* Pointer to first InterpPackage structure
				 * for interp. */
    Tcl_Interp *interp)		/* Interpreter that is being deleted. */
{
    InterpPackage *ipPtr, *nextPtr;

    ipPtr = (InterpPackage *) clientData;
    while (ipPtr != NULL) {
	nextPtr = ipPtr->nextPtr;
	ckfree((char *) ipPtr);
	ipPtr = nextPtr;
    }
}


TclFinalizeLoad(void)
{
    LoadedPackage *pkgPtr;

    /*
     * No synchronization here because there should just be one thread alive
     * at this point. Logically, packageMutex should be grabbed at this point,
     * but the Mutexes get finalized before the call to this routine. The
     * only subsystem left alive at this point is the memory allocator.
     */

    while (firstPackagePtr != NULL) {
	pkgPtr = firstPackagePtr;
	firstPackagePtr = pkgPtr->nextPtr;

#if defined(TCL_UNLOAD_DLLS) || defined(__WIN32__)
	/*
	 * Some Unix dlls are poorly behaved - registering things like atexit
	 * calls that can't be unregistered. If you unload such dlls, you get
	 * a core on exit because it wants to call a function in the dll after
	 * it has been unloaded.
	 */

	if (pkgPtr->fileName[0] != '\0') {
	    Tcl_FSUnloadFileProc *unLoadProcPtr = pkgPtr->unLoadProcPtr;
	    if (unLoadProcPtr != NULL) {
		(*unLoadProcPtr)(pkgPtr->loadHandle);
	    }
	}
#endif

	ckfree(pkgPtr->fileName);
	ckfree(pkgPtr->packageName);
	ckfree((char *) pkgPtr);