diff -r deec7e509f66 -r ca9a0fc2f082 contentmgmt/contentaccessfwfordrm/engineering/dox/Attributes.dox --- a/contentmgmt/contentaccessfwfordrm/engineering/dox/Attributes.dox Wed Oct 06 11:09:48 2010 +0530 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,161 +0,0 @@ -// 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: -// Each of these objects may have properties or attributes associated with it. This section -// outlines how applications can retrieve these using the CAF API. -//
-// Different agents may use different terms to describe the same concept. Generic attributes provide a -// way for applications to query standardised information about a content object. -// These standardised attributes are given by the enumeration ContentAccess::TAttribute. It is possible -// for agents to extend this set of attributes, starting from EAgentSpecificAttributeBase. -// The attribute functions are implemented in ContentAccess::CContent, ContentAccess::CData and -// ContentAccess::CManager. -// Retrieving a Single Attribute -// The attributes of one content object in a file may not necessarily be the same as the -// attributes of other content objects within the same file. Attributes relate to a single -// content object within a file. -// It is possible that the attribute may not make sense for a particular content object. In that -// case the agent will return an error KErrCANotSupported. If an attempt is made to -// retrieve the attributes of a content object that does not exist the agent will return KErrNotFound. -// The following code fragment illustrates how to retrieve an attribute for a particular -// object within a content file. -// CContent* content = CContent::NewL(uri); -// // check if DRM rights are pending for the object specified by uniqueId -// TInt attributeValue; -// TInt err = content->GetAttribute(ERightsPending, attributeValue, uniqueId); -// if(err == KErrNone) -// // Check the value of the attribute -// if(attributeValue == ETrue) -// // Rights are pending, display waiting for rights countdown -// else if(attributeValue == EFalse) -// // Rights are not pending -// else if(err == KErrCANotSupported) -// // This attribute does not apply to this content object -// else if(err == KErrNotFound) -// // Cannot find the object specified by the given uniqueId -// else if (err != KErrPermissionDenied) -// // Unknown error -// User::Leave(err); -// Retrieving Several Attributes -// For some agent implementations it may be more efficient to retrieve all the attributes for a content -// object in one function call. The ContentAccess::RAttributeSet object is used here to provide a way to -// request and store several attributes. -// Querying two attributes using the CManager API would look like the following: -// // Agent manager -// CManager *manager = CManager::NewLC(); -// // Prepare the attributes to query using the CAttributeSet object -// RAttributeSet attributeSet; -// CleanupClosePushL(attributeSet); -// attributeSet.AddL(EProtected); -// attributeSet.AddL(ECanView); -// // Retrieve the attribute values from the agent -// User::LeaveIfError(manager->GetAttributeSet(attributeSet, virtualPath)); -// // Check if the content object is protected -// TInt attributeValue; -// TInt err = attributeSet.GetValue(EProtected, attributeValue); -// if(err == KErrNone && attributeValue) -// // content object is DRM protected -// // Check if the content object can be display on screen -// TInt err = attributeSet.GetValue(ECanView, attributeValue); -// if(err == KErrNone && attributeValue) -// // content object has rights that allow it to be displayed on screen -// // Finished -// CleanupStack::PopAndDestroy(2); // manager, attributeSet -//
-// String attributes are similar to the attributes described above except the value associated -// with the attribute is a string. A good example of where a string attribute is required is the -// MIME type of a content object within a file. -// The string attributes are standardised by the ContentAccess::TStringAttribute enumeration. This -// allows applications to request information such as the MIME type in a generic way for all agents. -// Agents can extend this mechanism to provide agent specific attributes starting at -// EAgentSpecificStringAttributeBase. -// The following example finds the author of a content object. -// CContent* content = CContent::NewL(uri); -// // define a buffer to store the attribute value string -// TBuf <100> buf; -// // retrieve the attribute -// err = content->GetAttribute(EAuthor, authorBuffer, uniqueId); -// // Display the authors name on screen -// if (err == KErrNone) -// DisplayAuthor(buf); -// If the Agent does not support this attribute, it will return KErrCANotSupported. -// Retrieving Several String Attributes -// For some agent implementations it may be more efficient to retrieve several string attributes for a content -// object in one function call. The ContentAccess::RStringAttributeSet object is used here to provide a way to -// request and store several attributes. -// Querying three attributes using the CManager API would look like the following: -// CManager *manager = CManager::NewLC(); -// // Prepare the attributes to query using the CAttributeSet object -// RStringAttributeSet stringAttributeSet; -// CleanupClosePushL(stringAttributeSet); -// stringAttributeSet.AddL(ETitle); -// stringAttributeSet.AddL(EAuthor); -// stringAttributeSet.AddL(EDescription); -// // Retrieve the attribute values from the agent -// User::LeaveIfError(manager->GetStringAttributeSet(stringAttributeSet, virtualPath)); -// // Display the values -// TBuf <256> value; -// TInt err = stringAttributeSet.GetValue(ETitle, value); -// if(err == KErrNone) -// Printf("Title : %s", value); -// err = stringAttributeSet.GetValue(EAuthor, value); -// if(err == KErrNone) -// Printf("Author : %s", value); -// err = stringAttributeSet.GetValue(EDescription, value); -// if(err == KErrNone) -// Printf("Description : %s", value); -// // Finished -// CleanupStack::PopAndDestroy(2); // manager, stringAttributeSet -//
-// Some agents may expose meta data so they can be read using a \c CData object. The format -// of these meta-data objects is not specified by the Content Access Framework but could -// be useful for applications familiar with the agent to read meta data this way. -// \c CData objects for agent specific meta-data can be opened in the same way content objects -// are opened using the ContentAccess::CContent::OpenContentL() function. -// CContent* content = CContent::NewLC(uri); -// // Create an array to store the embedded objects -// RStreamablePtrArray myArray; -// CleanupClosePushL(myArray); -// // Get the embedded "Agent Specific" objects in the current container -// content->GetEmbeddedObjectsL(myArray, EAgentSpecificObject); -// // Get the unique Id of the first meta-data object -// TPtrC aUniqueId = myArray[0]->UniqueId(); -// // create a CData object to read the meta data -// CData *myMetaData = content->OpenContentLC(EPeek, aUniqueId); -// // Do something with the data -// // Finished -// CleanupStack::PopAndDestroy(3); // content, myArray, myMetaData -//
-// -// - -/** - @page ContentAttributes Content Object Attributes - As shown in the @ref CContentAPI "Consumer API", a file may consist of many content and container objects. - - @ref CAFAttributes - - @ref CAFStringAttributes - - @ref CAFAgentSpecificMetaData - @section CAFAttributes Generic Attributes - @code - @endcode - @code - @endcode - @section CAFStringAttributes Generic String attributes - @code - @endcode - @code - @endcode - @section CAFAgentSpecificMetaData Agent specific meta-data - @code - @endcode -*/