/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 * This file is part of the LibreOffice project.
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 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
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 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
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 */

#ifndef INCLUDED_COMPHELPER_DOCPASSWORDHELPER_HXX
#define INCLUDED_COMPHELPER_DOCPASSWORDHELPER_HXX

#include <com/sun/star/beans/NamedValue.hpp>
#include <comphelper/comphelperdllapi.h>
#include <vector>
#include <comphelper/docpasswordrequest.hxx>

namespace com { namespace sun { namespace star { namespace task { class XInteractionHandler; } } } }
namespace com { namespace sun { namespace star { namespace beans { struct PropertyValue; } } } }

namespace comphelper {

enum DocPasswordVerifierResult
{
    DocPasswordVerifierResult_OK,
    DocPasswordVerifierResult_WRONG_PASSWORD,
    DocPasswordVerifierResult_ABORT
};



/** Base class for a password verifier used by the DocPasswordHelper class
    below.

    Users have to implement the virtual functions and pass an instance of the
    verifier to one of the password request functions.
 */
class COMPHELPER_DLLPUBLIC IDocPasswordVerifier
{
public:
    virtual             ~IDocPasswordVerifier();

    /** Will be called every time a password needs to be verified.

        @param rPassword
            The password to be verified

        @param o_rEncryptionData
            Output parameter, that is filled with the EncryptionData generated
            from the password. The data is filled only if the validation was
            successful.

        @return  The result of the verification.
            - DocPasswordVerifierResult_OK, if and only if the passed password
              is valid and can be used to process the related document.
            - DocPasswordVerifierResult_WRONG_PASSWORD, if the password is
              wrong. The user may be asked again for a new password.
            - DocPasswordVerifierResult_ABORT, if an unrecoverable error
              occurred while password verification. The password request loop
              will be aborted.
     */
    virtual DocPasswordVerifierResult verifyPassword( const OUString& rPassword, css::uno::Sequence< css::beans::NamedValue >& o_rEncryptionData ) = 0;

    /** Will be called every time an encryption data needs to be verified.

        @param rEncryptionData
            The data will be validated

        @return  The result of the verification.
            - DocPasswordVerifierResult_OK, if and only if the passed encryption data
              is valid and can be used to process the related document.
            - DocPasswordVerifierResult_WRONG_PASSWORD, if the encryption data is
              wrong.
            - DocPasswordVerifierResult_ABORT, if an unrecoverable error
              occurred while data verification. The password request loop
              will be aborted.
     */
    virtual DocPasswordVerifierResult verifyEncryptionData( const css::uno::Sequence< css::beans::NamedValue >& o_rEncryptionData ) = 0;

};



/** Helper that asks for a document password and checks its validity.
 */
class COMPHELPER_DLLPUBLIC DocPasswordHelper
{
public:


    /** This helper function generates the information related
        to "Password to modify" provided by user. The result
        sequence contains the hash and the algorithm-related
        info.

        @param aString
            The string for which the info should be generated

        @return
            The sequence containing the hash and the algorithm-related info
      */

    static css::uno::Sequence< css::beans::PropertyValue >
        GenerateNewModifyPasswordInfo( const OUString& aPassword );



    /** This helper function allows to check whether
        the "Password to modify" provided by user is the correct one.

        @param aString
            The string containing the provided password

        @param aInfo
            The sequence containing the hash and the algorithm-info

        @return
            <TRUE/> if the password is correct one
            <FALSE/> otherwise
      */

    static bool IsModifyPasswordCorrect(
                const OUString& aPassword,
                const css::uno::Sequence< css::beans::PropertyValue >& aInfo );




    /** This helper function generates the hash code based on the algorithm
        specified by MS for "Password to modify" feature of Word.

        @param aString
            The string for which the hash should be calculated

        @return
            The hash represented by sal_uInt32
      */

    static sal_uInt32 GetWordHashAsUINT32(
                const OUString& aString );



    /** This helper function generates the hash code based on the algorithm
        specified by MS for "Password to modify" and passwords related to
        table protection of Excel.

        @param aString
            The string for which the hash should be calculated

        @param nEnc
            The encoding that should be used to generate the 8-bit string
            before the hash is generated

        @return
            The hash represented by sal_uInt16
      */

    static sal_uInt16 GetXLHashAsUINT16(
                const OUString& aString,
                rtl_TextEncoding nEnc = RTL_TEXTENCODING_UTF8 );



    /** This helper function generates the hash code based on the algorithm
        specified by MS for "Password to modify" and passwords related to
        table protection.

        @param aString
            The string for which the hash should be calculated

        @param nEnc
            The encoding that should be used to generate the 8-bit string
            before the hash is generated

        @return
            The hash represented by sequence of bytes in BigEndian form
      */

    static css::uno::Sequence< sal_Int8 > GetXLHashAsSequence(
                const OUString& aString,
                rtl_TextEncoding nEnc = RTL_TEXTENCODING_UTF8 );



    /** This helper function generates a random sequence of bytes of
        requested length.
      */

    static css::uno::Sequence< sal_Int8 > GenerateRandomByteSequence(
                sal_Int32 nLength );



    /** This helper function generates a byte sequence representing the
        key digest value used by MSCodec_Std97 codec.
      */

    static css::uno::Sequence< sal_Int8 > GenerateStd97Key(
                const OUString& aPassword,
                const css::uno::Sequence< sal_Int8 >& aDocId );



    /** This helper function generates a byte sequence representing the
        key digest value used by MSCodec_Std97 codec.
      */

    static css::uno::Sequence< sal_Int8 > GenerateStd97Key(
                const sal_uInt16 pPassData[16],
                const css::uno::Sequence< sal_Int8 >& aDocId );

    /** This helper function generates a byte sequence representing the
        key digest value used by MSCodec_Std97 codec.
      */

    static css::uno::Sequence< sal_Int8 > GenerateStd97Key(
                const sal_uInt16 pPassData[16],
                const sal_uInt8 pDocId[16] );



    /** This helper function tries to request and verify a password to load a
        protected document.

        First, the list of default passwords will be tried if provided. This is
        needed by import filters for external file formats that have to check a
        predefined password in some cases without asking the user for a
        password. Every password is checked using the passed password verifier.

        If not successful, the passed password of a medium is tried, that has
        been set e.g. by an API call to load a document. If existing, the
        password is checked using the passed password verifier.

        If still not successful, the passed interaction handler is used to
        request a password from the user. This will be repeated until the
        passed password verifier validates the entered password, or if the user
        chooses to cancel password input.

        @param rVerifier
            The password verifier used to check every processed password.

        @param rMediaPassword
            If not empty, will be passed to the password validator before
            requesting a password from the user. This password usually should
            be querried from a media descriptor.

        @param rxInteractHandler
            The interaction handler that will be used to request a password
            from the user, e.g. by showing a password input dialog.

        @param rDocumentUrl
            The URL of the related document that will be shown in the password
            input dialog.

        @param eRequestType
            The password request type that will be passed to the
            DocPasswordRequest object created internally. See
            docpasswordrequest.hxx for more details.

        @param pDefaultPasswords
            If not null, contains default passwords that will be tried before a
            password will be requested from the media descriptor or the user.

        @param pbIsDefaultPassword
            (output parameter) If not null, the type of the found password will
            be returned. True means the password has been found in the passed
            list of default passwords. False means the password has been taken
            from the rMediaPassword parameter or has been entered by the user.

        @return
            If not empty, contains the password that has been validated by the
            passed password verifier. If empty, no valid password has been
            found, or the user has chossen to cancel password input.
     */
    static css::uno::Sequence< css::beans::NamedValue > requestAndVerifyDocPassword(
                            IDocPasswordVerifier& rVerifier,
                            const css::uno::Sequence< css::beans::NamedValue >& rMediaEncData,
                            const OUString& rMediaPassword,
                            const css::uno::Reference< css::task::XInteractionHandler >& rxInteractHandler,
                            const OUString& rDocumentUrl,
                            DocPasswordRequestType eRequestType,
                            const ::std::vector< OUString >* pDefaultPasswords = nullptr,
                            bool* pbIsDefaultPassword = nullptr );

private:
                        ~DocPasswordHelper();
};



} // namespace comphelper

#endif

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