/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: NPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is 
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or 
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the NPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the NPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/* Dll
 *
 * Programmatic representation of a dll. Stores modifiedTime and size for
 * easy detection of change in dll.
 *
 * dp Suresh <dp@netscape.com>
 */

#ifndef xcDll_h__
#define xcDll_h__

#include "prio.h"
#include "prlink.h"
#include "nsISupports.h"
#include "nsILocalFile.h"
#include "nsCOMPtr.h"
#include "nsString.h"

class nsIModule;
class nsIServiceManager;

typedef enum nsDllStatus
{
	DLL_OK = 0,
	DLL_NO_MEM = 1,
	DLL_STAT_ERROR = 2,
	DLL_NOT_FILE = 3,
	DLL_INVALID_PARAM = 4
} nsDllStatus;

class nsDll
{
private:
    char *m_dllName;			// Stores the dllName to load.

    nsCOMPtr<nsIFile> m_dllSpec;	    // Filespec representing the component

	PRLibrary *m_instance;	// Load instance
	nsDllStatus m_status;	// holds current status
    nsIModule *m_moduleObject;

    // Cache frequent queries
    nsCString m_persistentDescriptor;
    nsCString m_nativePath;

    PRBool m_markForUnload;
    char *m_registryLocation;

    void Init(nsIFile *dllSpec);
    void Init(const char *persistentDescriptor);

    void BreakAfterLoad(const char *nsprPath);

public:
 
	nsDll(nsIFile *dllSpec, const char *registryLocation);
	nsDll(const char *persistentDescriptor);
    nsDll(const char *dll, int type /* dummy */);

	~nsDll(void);

	// Status checking on operations completed
	nsDllStatus GetStatus(void) { return (m_status); }

	// Dll Loading
	PRBool Load(void);
	PRBool Unload(void);
	PRBool IsLoaded(void)
	{
		return ((m_instance != 0) ? PR_TRUE : PR_FALSE);
	}
    void MarkForUnload(PRBool mark) { m_markForUnload = mark; }
    PRBool IsMarkedForUnload(void) { return m_markForUnload; }

    // Shutdown the dll. This will call any on unload hook for the dll.
    // This wont unload the dll. Unload() implicitly calls Shutdown().
    nsresult Shutdown(void);

	void *FindSymbol(const char *symbol);
	
    PRBool HasChanged(void);

    // WARNING: DONT FREE string returned.
    const char *GetDisplayPath(void);
    // WARNING: DONT FREE string returned.
    const char *GetPersistentDescriptorString(void);
    // WARNING: DONT FREE string returned.
    const char *GetRegistryLocation(void) { return m_registryLocation; }
	PRLibrary *GetInstance(void) { return (m_instance); }

    // NS_RELEASE() is required to be done on objects returned
    nsresult GetDllSpec(nsIFile **dllSpec);
    nsresult GetModule(nsISupports *servMgr, nsIModule **mobj);
};

#endif /* xcDll_h__ */
