/* 

 * tclWinLoad.c --

 *

 *	This procedure provides a version of the TclLoadFile that

 *	works with the Windows "LoadLibrary" and "GetProcAddress"

 *	API for dynamic loading.

 *

 * 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: tclWinLoad.c,v 1.15 2002/10/10 12:25:53 vincentdarley Exp $

 */

#include "tclWinInt.h"

/*

 *----------------------------------------------------------------------

 *

 * TclpDlopen --

 *

 *	Dynamically loads a binary code file into memory and returns

 *	a handle to the new code.

 *

 * Results:

 *	A standard Tcl completion code.  If an error occurs, an error

 *	message is left in the interp's result.

 *

 * Side effects:

 *	New code suddenly appears in memory.

 *

 *----------------------------------------------------------------------

 */

int

TclpDlopen(interp, pathPtr, loadHandle, unloadProcPtr)

    Tcl_Interp *interp;		/* Used for error reporting. */

    Tcl_Obj *pathPtr;		/* Name of the file containing the desired

				 * code (UTF-8). */

    Tcl_LoadHandle *loadHandle;	/* Filled with token for dynamically loaded

				 * file which will be passed back to 

				 * (*unloadProcPtr)() to unload the file. */

    Tcl_FSUnloadFileProc **unloadProcPtr;	

				/* Filled with address of Tcl_FSUnloadFileProc

				 * function which should be used for

				 * this file. */

{

    HINSTANCE handle;

    CONST TCHAR *nativeName;

    /* 

     * First try the full path the user gave us.  This is particularly

     * important if the cwd is inside a vfs, and we are trying to load

     * using a relative path.

     */

    nativeName = Tcl_FSGetNativePath(pathPtr);

    handle = (*tclWinProcs->loadLibraryProc)(nativeName);

    if (handle == NULL) {

	/* 

	 * Let the OS loader examine the binary search path for

	 * whatever string the user gave us which hopefully refers

	 * to a file on the binary path

	 */

	Tcl_DString ds;

        char *fileName = Tcl_GetString(pathPtr);

	nativeName = Tcl_WinUtfToTChar(fileName, -1, &ds);

	handle = (*tclWinProcs->loadLibraryProc)(nativeName);

	Tcl_DStringFree(&ds);

    }

    *loadHandle = (Tcl_LoadHandle) handle;

    if (handle == NULL) {

	DWORD lastError = GetLastError();

#if 0

	/*

	 * It would be ideal if the FormatMessage stuff worked better,

	 * but unfortunately it doesn't seem to want to...

	 */

	LPTSTR lpMsgBuf;

	char *buf;

	int size;

	size = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |

		FORMAT_MESSAGE_ALLOCATE_BUFFER, NULL, lastError, 0,

		(LPTSTR) &lpMsgBuf, 0, NULL);

	buf = (char *) ckalloc((unsigned) TCL_INTEGER_SPACE + size + 1);

	sprintf(buf, "%d %s", lastError, (char *)lpMsgBuf);

#endif

	Tcl_AppendResult(interp, "couldn't load library \"",

			 Tcl_GetString(pathPtr), "\": ", (char *) NULL);

	/*

	 * Check for possible DLL errors.  This doesn't work quite right,

	 * because Windows seems to only return ERROR_MOD_NOT_FOUND for

	 * just about any problem, but it's better than nothing.  It'd be

	 * even better if there was a way to get what DLLs

	 */

	switch (lastError) {

	    case ERROR_MOD_NOT_FOUND:

	    case ERROR_DLL_NOT_FOUND:

		Tcl_AppendResult(interp, "this library or a dependent library",

			" could not be found in library path",

			(char *) NULL);

		break;

	    case ERROR_PROC_NOT_FOUND:

		Tcl_AppendResult(interp, "could not find specified procedure",

			(char *) NULL);

		break;

	    case ERROR_INVALID_DLL:

		Tcl_AppendResult(interp, "this library or a dependent library",

			" is damaged", (char *) NULL);

		break;

	    case ERROR_DLL_INIT_FAILED:

		Tcl_AppendResult(interp, "the library initialization",

			" routine failed", (char *) NULL);

		break;

	    default:

		TclWinConvertError(lastError);

		Tcl_AppendResult(interp, Tcl_PosixError(interp),

			(char *) NULL);

	}

	return TCL_ERROR;

    } else {

	*unloadProcPtr = &TclpUnloadFile;

    }

    return TCL_OK;

}

/*

 *----------------------------------------------------------------------

 *

 * TclpFindSymbol --

 *

 *	Looks up a symbol, by name, through a handle associated with

 *	a previously loaded piece of code (shared library).

 *

 * Results:

 *	Returns a pointer to the function associated with 'symbol' if

 *	it is found.  Otherwise returns NULL and may leave an error

 *	message in the interp's result.

 *

 *----------------------------------------------------------------------

 */

Tcl_PackageInitProc*

TclpFindSymbol(interp, loadHandle, symbol) 

    Tcl_Interp *interp;

    Tcl_LoadHandle loadHandle;

    CONST char *symbol;

{

    Tcl_PackageInitProc *proc = NULL;

    HINSTANCE handle = (HINSTANCE)loadHandle;

    /*

     * For each symbol, check for both Symbol and _Symbol, since Borland

     * generates C symbols with a leading '_' by default.

     */

    proc = (Tcl_PackageInitProc *) GetProcAddress(handle, symbol);

    if (proc == NULL) {

	Tcl_DString ds;

	Tcl_DStringInit(&ds);

	Tcl_DStringAppend(&ds, "_", 1);

	symbol = Tcl_DStringAppend(&ds, symbol, -1);

	proc = (Tcl_PackageInitProc *) GetProcAddress(handle, symbol);

	Tcl_DStringFree(&ds);

    }

    return proc;

}

/*

 *----------------------------------------------------------------------

 *

 * TclpUnloadFile --

 *

 *	Unloads a dynamically loaded binary code file from memory.

 *	Code pointers in the formerly loaded file are no longer valid

 *	after calling this function.

 *

 * Results:

 *	None.

 *

 * Side effects:

 *	Code removed from memory.

 *

 *----------------------------------------------------------------------

 */

void

TclpUnloadFile(loadHandle)

    Tcl_LoadHandle loadHandle;	/* loadHandle returned by a previous call

				 * to TclpDlopen().  The loadHandle is 

				 * a token that represents the loaded 

				 * file. */

{

    HINSTANCE handle;

    handle = (HINSTANCE) loadHandle;

    FreeLibrary(handle);

}

/*

 *----------------------------------------------------------------------

 *

 * TclGuessPackageName --

 *

 *	If the "load" command is invoked without providing a package

 *	name, this procedure is invoked to try to figure it out.

 *

 * Results:

 *	Always returns 0 to indicate that we couldn't figure out a

 *	package name;  generic code will then try to guess the package

 *	from the file name.  A return value of 1 would have meant that

 *	we figured out the package name and put it in bufPtr.

 *

 * Side effects:

 *	None.

 *

 *----------------------------------------------------------------------

 */

int

TclGuessPackageName(fileName, bufPtr)

    CONST char *fileName;	/* Name of file containing package (already

				 * translated to local form if needed). */

    Tcl_DString *bufPtr;	/* Initialized empty dstring.  Append

				 * package name to this if possible. */

{

    return 0;

}