/* 

  * 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;

 }