// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "Symbian Foundation License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.symbianfoundation.org/legal/sfl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// NOTE: For the purpose of clarity we have ommitted full error checking in the 

// <hr>

// The Supplier API allows agents to publicise the MIME types they are 

// interested in. When those files arrive on the device, message handling

// applications can check these MIME types and import the file 

// into CAF. The agent transforms the file into a different format

// for use within the device. 

// In most cases this won't be necessary, since the files will arrive in the 

// same format that they will be used in. However, some agents require the device 

// to protect (encrypt) the content at the moment it arrives; the Supplier 

// API fulfills that role.

// The classes used in the supply operation are:

// <code>ContentAccess::CSupplier</code> and instances of <code>ContentAccess::CImportFile</code>.

// <hr>

// The <code>ContentAccess::CSupplier</code> is designed to allow several unrelated files to be imported 

// into CAF. It uses its <code>ContentAccess::CAgentResolver</code> member to determine 

// which CA agent should be used to import each file. The <code>CAgentResolver</code> builds 

// a list of all agents when it is created and updates the list if new agents

// are installed.

// A typical import session will start with the creation of a <code>CSupplier</code>, e.g.,

// //Create Supplier

// CSupplier *mySupplier = CSupplier::NewL();

// Most applications will have a preference for the directory where output files

// are to be stored. Usually the first thing to do with the new <code>CSupplier</code> instance 

// is to set the output path. 

// //Set output path for DRM protected content

// _LIT(KPath,"C:\myOutputFiles");

// mySupplier->SetOutputDirectoryL(KPath());

// It is not necessary to set the output path if the application

// provides output file handles to the agent.

// <hr>

// <b> Check that the MIME type is supported </b>

// Before importing a file into the content access framework, an application

// should check that the MIME type of the file is supported. Each agent publishes a 

// list of the MIME types it supports. The list is configured in the agent's 

// resource file and can be checked using <code>ContentAccess::CSupplier::IsImportSupported()</code>

// if(!mySupplier->IsImportSupported(myMimeType))

// return;

// <b> Create a CMetaDataList object </b>

// The <code>CMetaDataList</code> object is used to store any information associated with the import file that

// may be useful for the agent. These values will be passed to the agent.

// For example OMA DRM 1.0 files sometimes arrive with the HTTP header 

// <code>X-Oma-Drm-Separate-Delivery</code>. This informs the agent how long before rights are expected 

// for the content. If the rights were expected in 12 seconds it would be something like 

// the following:

// // Create meta-data array

// CMetaDataArray *metaDataArray = new (ELeave) CMetaDataArray();

// CleanupStack::PushL(metaDataArray);

// // Add any useful information we can think of....

// metaDataArray->AddL(_L("Content Type"), _L("application/vnd.oma.drm.dm"));

// metaDataArray->AddL(_L("X-Oma-Drm-Separate-Delivery"), _L("12"));

// The file is 'written' to CAF using a <code>ContentAccess::CImportFile</code> object. 

// <code>ContentAccess::CSupplier::ImportFile()</code> creates an <code>CImportFile</code> object for importing a file. 

// The parameters supplied indicate whether the agent will create the output files or whether

// the application using CAF will generate output files for the agent on demand.

// // Create the import object, passing in the metaDataArray created earlier

// // The application will supply the output files

// CImportFile *import = mySupplier->ImportFileL(sourceMimeType, *metaDataArray);

// The application should now transfer the file to CAF using the <code>CImportFile</code> object. 

// Only one file can be transferred by each instance although several output files

// may be produced. Applications should create new <code>CImportFile</code> objects in order to import more files.

// <b> Agents Generating the Output files </b>

// If the application wants the agent to generate the output files, it should supply a suggested

// file name in the call to <code>CSupplier::ImportFile()</code>. Even if this parameter is a zero length

// descriptor, it still indicates that the agent is responsible for generating output files.

// Agents will create the output files in a directory nominated by the application when it called

// <code>CSupplier::SetOutputDirectoryL()</code> or they may decide to store the output files in their private 

// directory.

// Applications should check at the end of the import to find out how many output files were created

// and where they are stored.

// <b> Application generating the Output files</b>

// If no suggested file name is passed to the agent, the application will provide output files for

// the agent to use. This mechanism allows applications to open files in their own private directory and 

// ask the CAF agent to store the output in those files. 

// The way it works is the same as an any other import operation, the difference is that the call 

// to <code>CImportFile::WriteData()</code> or <code>CImportFile::WriteComplete()</code> may return an error code of 

// <code>KErrCANewFileHandleRequired</code>. 

// This error code indicates that the agent needs a new output file handle in order to continue. The 

// application should open a new output file with write access and call <code>CImportFile::ContinueWithNewOutputFile()</code> 

// to supply the new handle to the agent. It is possible that further handles may be needed, if so 

// <code>CImportFile::ContinueWithNewOutputFile()</code> will return <code>KErrCANewFileHandleRequired</code> and the application should 

// repeat the procedure with another file.

// The agent must cache its state before returning <code>KErrCANewFileHandleRequired</code>. The application MUST NOT resend

// the same <code>WriteData()</code> or <code>WriteComplete()</code> command.

// At the end of the import operation the output files will still be listed regardless of whether

// they were supplied by the application or the agent.

// <hr>

// <code>ContentAccess::CImportFile</code> is the class used to write the file data to CAF. 

// It is created by <code>ContentAccess::CSupplier</code> and can only be used to import a single file.

// An application should call <code>WriteData()</code> to transfer a field in 'chunks' to the Content 

// Access Framework. Usually this would be something like the following:

// TFileName fileName;

// TBuf8<128> data;

// TInt err = KErrNone;

// // start importing content

// while( (source still has data) && (err==KErrNone) )

// source.read(data);

// err = import->WriteData(data);

// // need to supply new file to import to ?

// while (err == KErrCANewFileHandleRequired)		

// // supply new file in order to continue writing

// RFile newFile;

// import->GetSuggestedOutputFileName(fileName);

// newFile.Open(fileName, EFileWrite);

// err = import->ContinueWithNewOutputFile(newFile, fileName);

// newFile.Close();

// <hr>

// When all the data is written, the application should call <code>ContentAccess::CImportFile::WriteComplete()</code>, this will 

// let the agent know that all the data has been transferred and allow it to perform any final processing.

// err = import->WriteComplete();

// // When application supplies file handles it must always check to see if 

// // the agent needs a new file handle

// while(err == KErrCANewFileHandleRequired)

// RFile newFile;

// import->GetSuggestedOutputFileName(fileName);

// newFile.Open(fileName, EFileWrite);

// err = import->ContinueWithNewOutputFile(newFile, filename);

// // It is possible that the agent needs yet another file handle

// newFile.Close();   // agent makes a copy so we don't need to keep our file handle

// At this stage all the agent's work is done, the <code>CImportFile</code> object can be deleted.

// <hr>

// When the import is finished the application may wish to check if any output files have 

// been produced. The list of output files is accessed using <code>ContentAccess::CImportFile::OutputFileL()</code>.

// // loop over all the output files produced

// for(TInt i =0; i < import->OutputFileCountL(); i++)

// // Can now retrieve filename, type of file (receipt or content) and 

// // MIME type for the file produced

// TPtr filename =	import->OutputFileL(i).FileName();

// TOutputType type = import->OutputFileL(i).OutputType();

// TPtr8 mimetype = import->OutputFileL(i).MimeType();

// The output files can be either content files or receipts for DRM rights. It is possible that no output

// files will be generated and the file will be "absorbed" into the agent.

// Also, it is important to remember that the MIME type and most likely the file extension of the output files are 

// almost certainly different to the MIME type and file extension of the imported file.

// <hr>

// 

//

/**

 @page CSupplierAPI Importing files into the Content Access Framework

 - @ref SupplierAPI

 - @ref ImportSession

 - @ref ImportCAF

 - @ref Importfile

 - @ref ImportComplete 

 - @ref ImportOutput

 code examples given below. For examples with error checking see @ref ExampleSupplier2.

 @section SupplierAPI Supplier API

 @section ImportSession Starting a new import session

 @code

 @endcode

 @code

 @endcode

 @section ImportCAF Preparing to import the file

 @code

 @endcode

 @code

 @endcode

 @section ImportFile Creating the CImportFile object

 @code

 @endcode

 @section Importfile Transferring the file to the Content Access Agent

 @code

 @endcode

 @section ImportComplete Completing the Import

 @code 

 @endcode

 @section ImportOutput Output files produced

 @code

 @endcode

*/