// 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 "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// <hr>

// The Content Access Framework is at released status in Symbian OS v9.1

// <hr>

// The Symbian OS Content Access Framework (CAF) provides services that

// enable agents to publish content in a generic manner that is easy for 

// applications to use. 

// Applications will access content the same way regardless of whether the

// content is plain text, located in a server's private directory, or

// DRM protected.

// Content can be, for example, media files or a level in a game; applications

// would be, for example, a video/sound player or an internet browser; 

// DRM stands for Digital Rights Management.

// <hr>

// The CAF defines an ECom plug-in interface, for third-party CAF Agents. The interface

// allows new agents to be integrated at a later date, dynamically if required. 

// The specification for this interface can be found in <code>ContentAccess::CAgentFactory</code>.

// CAF Agents can be written to provide the following functions:

// The CAF framework does not provide any capability enforcement so it is the responsiblity 

// of the agent to police access to the APIs. The agent can choose to deny some operations 

// in the CAF API based upon application's capabilities or the agent's own policy relating 

// to the use of that API. 

// <hr>

// <code>ContentAccess::CAgentFactory</code>. This is the ECom interface for a CAF Agent.

// The agent's factory will produce products derived from:

// -# <code>ContentAccess::CAgentContent</code>

// -# <code>ContentAccess::CAgentData</code>

// -# <code>ContentAccess::CAgentImportFile</code>

// -# <code>ContentAccess::CAgentManager</code>

// -# <code>ContentAccess::CAgentRightsManager</code>

// These products provide the services described in the introduction (above) on a per 

// agent basis.

// <hr>

// Generally, these APIs fall into four areas:

// <b>Supplier API</b> 

// The Supplier API is used to handle the delivery and transformation of content.

// It can be used to transform DRM protected files when they arrive on a device into 

// a form that allows them to be stored securely on the device.

// It can also be used intercept content and ensure it is stored in an agent's private 

// directory.

// See the classes <code>ContentAccess::CSupplier</code> and <code>ContentAccess::CImportFile</code>

// <b>Consumer API</b> 

// Allows applications to read the content as if it were stored as plain text regardless

// of how it is actually stored on the device. For instance it might be encrypted.

// The consumer API will be used by applications rendering content and/or multimedia 

// plug-ins. By rendering we mean reading data from a file, transforming it, then playing 

// or displaying it on the device.

// See the classes <code>ContentAccess::CContent</code> and <code>ContentAccess::CData</code>.

// <b>Manager API</b> 

// The management of files and content access agents.

// See <code>ContentAccess::CManager</code>

// <b>Rights Manager API</b> 

// A generic API used to manage DRM rights within a particular DRM agent

// See <code>ContentAccess::CRightsManager</code>

// <hr>

// An archive file contains content objects and other containers within the file. Each

// container within the file may contain more content objects or further containers.

// Common examples of archive files are zip and tar files.

// The Content Access Framework allows applications to open archive files and read 

// content from inside them. The content objects and containers inside the 

// file can be traversed using the <code>ContentAccess::CContent</code> class. 

// This class allows applications to use the content within these container files 

// without needing to understand any specifics of the compression or storage mechanism 

// used by the archive.

// <hr>

// The Content Access Framework also provides an abstact way to access DRM protected 

// content. An agent can be designed to implement a DRM scheme.

// Applications use DRM protected files in the same way they would use any other file. 

// The agent enforces the rights applied to the content. Also, it prevents access when rights

// have expired or if the file is accessed by applications without DRM capability.

// To enforce the protection of the content the agent must know what the client intends 

// to do with the content once it has read the plain-text version of that content. Therefore, applications must 

// Applications should \b always specify their intent, whether or not they will using DRM protected content. 

// Non-DRM agents will just ignore the call, but it means the application does not need to treat DRM content 

// as a special case.

// One occasion where applications do need to treat DRM as a special case is where User Interface menu 

// Applications can use the <code>GetAttribute()</code> functions to determine whether the operation is allowed on any 

// given content object.

// Finally any application or plug-in that reads DRM content must handle the unencrypted version of 

// the content responsibly. Only applications proven to work this way will be given the DRM capability. 

// <hr>

// The evaluation of DRM rights hinges on the correct supply of 'DRM

// Intent' from the trusted rendering application to the Content Access

// Framework. The framework provides a number of options so that the

// application can query and evaluate rights appropriately. 

// Briefly, the CAF allows a renderer to:

// - <b>Evalute intent</b> \n

// e.g., ask the question "Could I play this now if I wanted to?". \n

// Here, the ability is queried, but no stateful rights modifications are made.

// - <b>Execute intent</b> \n

// e.g., indicate "I have played this now". \n

// In this example, the CAF would instruct the agent to evaluate and process

// the rights, thus modifying any stateful rights 

// (i.e., rights that have state, e.g. content that has an expiry date or content that can only be played three times, say).

// Essentially, renders will begin by evaluating intent when the \c CData object

// is created. When the content has been rendered successfully, they will execute 

// the intent to ensure that stateful rights are then processed.

// The recommended intent values (for renders and agents to support) are given in <code>ContentAccess::TIntent</code>:

// - \c EPeek: Do not process or evaluate rights in any way

// - \c EPlay: Play the target content (OMA)

// - \c Eview: View the target content (OMA)

// - \c EExecute: Execute the target content (OMA). Note: only supported in

// a Java context

// - \c EPrint: Print the target content (OMA)

// - \c EPause: Pause content playback

// - \c EContinue: Continue content playback

// - \c EUnknown: Client has no idea what the content will be used for. DRM Agents can deny this intent allowing only unprotected content to be accessed this way.

// <hr>

// The F32 Agent provides access to unprotected files. It is really just a wrapper around <code>RFile</code>.

// The Content Access Framework treats the F32 agent as a special case. If no other suitable 

// agent is responsible for a file or directory the F32 Agent will be used. 

// The F32 Agent runs in the same process and thread as the calling application so any 

// file operations it performs will be limited to the file operations permitted for 

// the calling application's process

// <hr>

// Some agents may provide access to files stored in their private directory. They

// can advertise the files' existence to applications through their implementation 

// of the <code>ContentAccess::CAgentManager::GetDir()</code> function.

// In the file system the private directories have the format 

// <code>\\private\\xxxxxxxx\\directory_1\\...directory_n\\filename.ext</code>

// where <code>xxxxxxxx</code> is the UID of the agent.

// CAF will translate that path so applications see the file as:

// <code>\\private\\agent_name\\directory_1\\...directory_n\\filename.ext</code>

// where <code>agent_name</code> is the name of the agent.

// When an application opens a file stored in the private directory, CAF selects the 

// agent which handles that content based upon the name in the path. If the file is not 

// stored in a private directory, CAF asks each of the agents in turn whether they support 

// the file. If no agent supports the file, it will be read as plaintext using the <code>F32Agent</code>.

// <hr>

// - <code>CAF.DLL</code>        - Content Access Framework (the application level APIs)

// - <code>CAFUTILS.DLL</code>   - Utility classes used by agents, applications and CAF itself

// - <code>F32AGENT.DLL</code>   - Agent for reading unprotected files

// - <code>F32AGENTUI.DLL</code> - Agent for reading unprotected files

// - <code>RECCAF.DLL</code>     - Data Recognizer for all agents within the Content Access Framework

// <hr>

// 

//

/**

 @page CAFIntroduction Introduction

 @section CAF_Contents Contents

 - @ref CAF_Status

 - @ref CAF_Intro

 - @ref CAF_Agents

 - @ref CAF_Agent_Interfaces

 - @ref CAFAPIs

 - @ref AboutArchives

 - @ref AboutDRM

 - @ref CAF_Intent

 - @ref AboutF32Agent

 - @ref AboutPrivDir

 - @ref CAF_Delivery

 @section CAF_Status Status

 @section CAF_Intro Overview

 @section CAF_Agents CAF Agents

 @li Indirect access to a private server directory

 @li Plain text access to protected content (even if the content is encrypted)

 @section CAF_Agent_Interfaces Agent Interfaces

 A CAF agent @e must implement a concrete factory derived from 

 @section CAFAPIs Content Access Framework APIs

 @section AboutArchives Access to content within archive files

 @section AboutDRM Digital Rights Management (DRM)

 specify their intent before using DRM protected content, see @ref CAF_Intent. 

 items may need to be disabled. For example, @e save or <i>send via Bluetooth</i> may not be permitted. 

 @section CAF_Intent DRM Intent

 @section AboutF32Agent The F32 Agent

 @section AboutPrivDir Sharing Content in a Private Directory

 @section CAF_Delivery Delivery

*/