/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla 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/MPL/
 *
 * 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):
 *   Benjamin Smedberg <benjamin@smedbergs.us>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of 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 MPL, 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 MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef nsXPCOMGlue_h__
#define nsXPCOMGlue_h__

#include "nscore.h"

class nsILocalFile;

/**
 * The following function is available in both the standalone and
 * dynamically linked versions of the glue.
 */

struct GREVersionRange {
    const char *lower;
    PRBool      lowerInclusive;
    const char *upper;
    PRBool      upperInclusive;
};

struct GREProperty {
    const char *property;
    const char *value;
};

/**
 * Locate the path of the xpcom shared library from a GRE with specified
 * properties.
 * 
 * @param versions         An array of version ranges: if any version range
 *                         matches, the GRE is considered acceptable.
 * @param versionsLength   The length of the versions array.
 * @param properties       A null-terminated list of GRE property/value pairs
 *                         which must all be satisfied.
 * @param propertiesLength Length of the properties array.
 * @param buffer           A buffer to be filled with the appropriate path. If
 *                         the "local" GRE is specified (via the USE_LOCAL_GRE
 *                         environment variable, for example), this buffer
 *                         will be set to the empty string.
 * @param buflen           The length of buffer. This must be at least
 *                         PATH_MAX/MAXPATHLEN.
 * @throws NS_ERROR_FAILURE if an appropriate GRE could not be found.
 * @note The properties parameter is ignored on macintosh, because of the
 *       manner in which the XUL frameworks are installed by version.
 * @note Currently this uses a "first-fit" algorithm, it does not select
 *       the newest available GRE.
 */
extern "C" NS_COM_GLUE nsresult
GRE_GetGREPathWithProperties(const GREVersionRange *versions,
                             PRUint32 versionsLength,
                             const GREProperty *properties,
                             PRUint32 propertiesLength,
                             char *buffer, PRUint32 buflen);

#ifdef XPCOM_GLUE

/**
 * The following functions are only available in the standalone glue.
 */

/**
 * Initialize the XPCOM glue by dynamically linking against the XPCOM
 * shared library indicated by xpcomFile.
 */
extern "C" NS_HIDDEN_(nsresult)
XPCOMGlueStartup(const char* xpcomFile);

typedef void (*NSFuncPtr)();

struct nsDynamicFunctionLoad
{
    const char *functionName;
    NSFuncPtr  *function;
};

/**
 * Dynamically load functions from libxul.
 *
 * @throws NS_ERROR_NOT_INITIALIZED if XPCOMGlueStartup() was not called or
 *         if the libxul DLL was not found.
 * @throws NS_ERROR_LOSS_OF_SIGNIFICANT_DATA if only some of the required
 *         functions were found.
 */
extern "C" NS_HIDDEN_(nsresult)
XPCOMGlueLoadXULFunctions(const nsDynamicFunctionLoad *symbols);

/**
 * Finish the XPCOM glue after it is no longer needed.
 */
extern "C" NS_HIDDEN_(nsresult)
XPCOMGlueShutdown();


/**
 * Locate the path of the XPCOM shared library of a compatible GRE.
 * The result of this function is normally passed directly to
 * XPCOMGlueStartup. This looks for the GRE version in
 * nsBuildID.h, which is generated at build time. Unless you set
 * MOZ_MILESTONE_RELEASE this will probably not be a useful GRE version string.
 *
 * @return string buffer pointing to the XPCOM DLL path. Callers do
 *         not need to free this buffer.
 * @status DEPRECATED - Use GRE_GetGREPathWithProperties
 */
extern "C" NS_HIDDEN_(char const *)
GRE_GetXPCOMPath();


/**
 * Locate the directory of a compatible GRE as an nsIFile
 *
 * @param _retval   Ordinary XPCOM getter, returns an addrefed interface.
 */
extern "C" NS_HIDDEN_(nsresult)
GRE_GetGREDirectory(nsILocalFile* *_retval);


/**
 * Embedding applications which don't need a custom
 * directoryserviceprovider may use GRE_Startup to start the XPCOM
 * glue and initialize the GRE in one step.
 */
extern "C" NS_HIDDEN_(nsresult)
GRE_Startup();


/**
 * Shut down XPCOM and the XPCOM glue in one step.
 */
extern "C" NS_HIDDEN_(nsresult)
GRE_Shutdown();

#endif // XPCOM_GLUE
#endif // nsXPCOMGlue_h__