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Here - CableLabs Community
Refactoring the MMI
contribution
Extending the look and feel
© NDS Ltd 2010. All rights reserved.
Reasoning
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
The original contribution from EchoStar works well and meets
MMI requirements
But
– Couldn‟t easily be re-skinned
– Behaviour could not be tailored
– Wanted to use elements elsewhere in the Stack
• Very useful basic HTML renderer
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The Standard MMI display
The standard display when a single MMI message has been
received.
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The Standard MMI display, thrice
How the display looks after three MMI open messages have been
received.
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The Alternate MMI Display
A quick re-skin later, and the display looks like this.
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Redeployment – basic
When an error is detected in the CableCARD communications, we
can display this OSD.
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Redeployment - advanced
The HTML renderer is now under control of a diagnostics
application.
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What was changed
Original
 HTML rendering in
HTMLComponent.java
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Rework
 HTML rendering now in
MiniBrowser.java with
useful interface
 Data fetched from
abstract UrlGetter
 Dialog now separate
entity
 Added mmi and ui classes
to allow inheritance
Data always fetched from
CableCARD
Dialog was part of
MMIDialog
Flat class structure
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Basic Class Diagram
UrlGetterListener
UrlGetter
DisplayManager
CableCardUrlGetter
MiniBrowser
DisplayManagerImpl
Dialog
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How can I add my own?
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Controlling the display
– Extend DisplayManager and implement these methods
• displayDialog()
• dismissDialog()
– Implement [if required] MiniBrowserListener to receive
updates in the HTML
• contentUpdated()
– Have your own paint()
• Otherwise, it won‟t look at all like you thought
– Create the extended DisplayManager
• You‟ll have to override & extend SystemModuleMgr to
instantiate an extended
SystemModuleRegistrarImpl that creates your new
DisplayManager class
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...and...

Extend ResidentMmiHandler if you want different behavior.
– We did this to enforce a single dialog
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Utilize the methods in MiniBrowser to display help prompts:
– hasLinks()
• true if the HTML page has a link that can be selected
– isScrollable()
• true if the HTML page is bigger than the window
– hasHistory()
• true if the user has selected any link and therefore can
go „back‟ in the browse history.
– Cleared when navigate() is called
– Use navigateBackwards() when back key is pressed
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Extended Class Diagram
DisplayManager
SystemManager
DisplayManagerImpl
SystemModuleMgr
SystemModuleRegistrarImpl
+getDisplayManager()
DisplayManagerExImpl
SystemModuleExMgr
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SystemModuleRegistrarExImpl
Word of warning
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The MMI display behaves like a „Well Behaved Application‟
– i.e. It informs of focus stolen
– But! It doesn‟t listen for focus lost
This means that if you decide to remove the ability to clear the
MMI display, you may find yourself in a whole new world of
hurt as you try to restore focus to the application...
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Using the MiniBrowser elsewhere
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Simply create one and give it the data!
OK, an example:
UrlGetter urlGetter = CableCardUrlGetter.getSession();
MiniBrowser browser = new MiniBrowser(urlGetter);
browser.registerMiniBrowserListener(this); // we implement MiniBrowserListener
// Now fetch the Applications from the POD... And then
PODApplication application = <PODManager>.getApplications().[<index>]
// Set the browser size and color, setBounds(), setBackground() etc.
// Add the browser to your own Container / Component
this.container.add(browser);
// And navigate to the app URL
browser.navigate(application.getURL());

Don‟t forget to add key passing
public void chUpKeyAction() {
browser.scrollVertically(MiniBrowser.SCROLL_UP_1_PAGE);
}
public void selectKeyAction() {
// Doesn’t matter if one is not selected, will call contentUpdated()
browser.followCurrentLink();
}
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Questions
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Thanks

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EchoStar for the original contribution
@ NDS
– Tom Gwozdz
– Laurentiu Dragan
– Madhusmitha Gottipati
– Bigi Porinju
@ Cablelabs
– Steve Maynard
@ Comcast
– Khurram Qureshi
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TDK
Test Development Environment.
© NDS Ltd 2010. All rights reserved.
TDK (Test Development Kit)
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The TDK was created so that Comcast could do integration
testing on the RI set tops.
The TDK runs on a computer/set top environment.
The TDK is built using Maven.
There are two parts to the TDK; the TDK server(Run on PC)
and the TDK app which is run on the set top.
The TDK uses TestNG for its reporting and maven for its
execution.
The TDK server tells the TDK app what tests to run and where
to get the test classes over a UDP socket connection.
The TDK works on top the Comcast CATS framework .
(Comcast proprietary software)
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NDS Contribution to the TDK


NDS has implemented over 500 test cases
Tests around
– Tuning
– Recording
– User key presses
– Time Shift Buffers
– Trick Play
– DSMCC downloading
– Section filtering
– Channel maps
– Performance
– Graphics
– …….
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Build The TDK.
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mvn clean install : build the entire TDK and run all the tests.
mvn clean install –DskipTests=true : Just build the TDK
After the TDK is built.
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You can execute individual test cases with the following
command
mvn test –Dgroups=TC0003,TC0006,….
Or execute the entire suite
mvn test
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TDK Execution.
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TDK tests start to execute.
TDK server opens socket to set top running TGShell app.
TDK tells TGShell app what test class to run and where it can
find that class file.
TGShell executes the class file and reports the results.
Once the TDK run finishes
the TestNG results can be found
in test/target/surefire-report
A detailed report with the test
passes/failures exists there.
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What is TGShell.

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TGShell is the app that is run on the set top.
All TGShell does is when launched opens a socket and waits to
be told what to do.
TGShell receives instructions from that open socket and creates
class files to be executed from those instructions.
TGShell then sends back the results of the execution over the
socket connection.
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CI with Hudson.
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With Hudson the RI can be built on a fixed schedule or even
monitor the SVN/CVS/GIT…. Repoisitory for updates which will
then trigger a new build to be preformed on the new src code.
If the RI build is successful another project can then be
triggered lets say the TDK to then test the new build.
All automated with build artifact/Test results archiving that can
be retrieved at any time.
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The End…..
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Demo
Q & A time 
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Version control
with Git and Gerrit
A different way of working with the RI
© NDS Ltd 2010. All rights reserved.
Question
Who has used Git at work or home before?
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What is Git

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Git is a distributed version control system (DVCS)
– It‟s non-centralized nature makes it ideal for loosely
coupled, widely distributed projects
Git was originally developed by Linus Torvalds for versioning
the Linux kernel
– Now used by a growing number of projects in both open
and closed source communities
Git is itself an open source project
– Available as source code under GPL
– Pre-built packages for all common platforms
– Free as in freedom, and free as in beer!
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What is Gerrit
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Gerrit is a web based code review and repository management
tool for Git
Gerrit is developed by Google and is used for the Android
project
Gerrit is an open source project and is available as a deployable
.war file
For an example have a look at the Android Gerrit
– https://review.source.android.com
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What is wrong with Subversion?
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Nothing, it‟s just not the best tool for this job
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SVN works in a very centralised, server dependent way
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SVN cannot import from other SVN repositories
– Except by using patches, but svn diff is very limited
SVN has poor support for branching and merging
And every now and again SVN gets confused and refuses to let
us commit – normally when we are trying to release
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What are the advantages of Git
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The biggest strength of Git is it‟s distributed nature
– Not dependant on a central server
– Once the initial clone is complete network access is only
required for updates and delivery
– Great for offline working
– Bringing in changes from other repo‟s is normal work flow
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Branching and merging are easy
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Understands SVN
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Reliable – doesn‟t break it‟s own repo
– Well, it hasn‟t yet…
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Our set up
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Although Git does not require or enforce a central server it is
good to have a definitive repository for releases and work
tracking
– The work is not done until it‟s in the definitive repository!
We use Gerrit for code reviews and to manage our repositories
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External
Cablelabs
SVN
Git repositories
SVN
Mirror
NDS SVN
To be retired
Main
Feature
Gerrit
Developers
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Benefits
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Easy merging of Cablelabs commits into our code base
Much better support for feature development
– Separate branch per feature
– Update the branch from the main line regularly
– Easy merge back of the feature once complete
Enforced code reviews
– And a guarantee that what is reviewed is what is committed
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The Future
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Cablelabs support of Git

Cablelabs are currently looking at adding support for Git
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Initially along side SVN
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Then maybe longer term moving across to Git completely
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The benefits for third parties of this would be
– Easier merging of releases
– Better visibility and tracking of fixes
It will also allow us to simplify our set up
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External
Cablelabs
SVN
Git repositories
Cablelabs
Git
Main
Feature
Gerrit
Developers
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Improving the contribution process?

Suggestion
– If Cablelabs were to have a public Gerrit in the same way
the Android project has, then third parties could contribute
fixes and features directly as a code review. Cablelabs and
other interested parties could review and comment on the
submission prior to it‟s acceptance.
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Any Questions?
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SNMP
Implementing ECN-1114 *
© NDS Ltd 2010. All rights reserved.
* and a few other things
© NDS Ltd 2010. All rights reserved.
The reasoning
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ECN-1114 simply states that Applications should be able to
query MIBs where data is supplied from the Stack.
Or the Platform
Or another Application
Or, come to think of it, the ECM
But that‟s not 1114 that‟s 1138 isn‟t it?
And there‟s probably an SNMP server in the Platform
Aargh.
So that‟s easy then.
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The setup
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We put an SNMP Master Agent in the Platform
We open up Agent X on the Master
We put an Agent X client in the Stack
– All the applications register with the Stack, we register via
Agent X with the Master
– All the Stack handlers register in the same way
– The Platform supports queries with its own Agent X client
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We use snmp4j to do this
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Cup of tea and a biscuit, job done
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The sting
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Whadja mean “snmp4j doesn‟t work in the RI”?
Oh, I see, it wants a full J2SE 1.4.2 JVM because it makes
extensive use of nio
So let‟s go find an open source SNMP client we can use...
That we can use.
– And would run on PBP 1.1 – Not J2SE 1.5
We can use.
– And didn‟t upset our lawyers quite so much
Eventually, Hello to the University of Coimbra
And Drexel University
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The fun
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Drexel‟s SNMP implementation was OK.
– We needed to wrap it up a little in case the lawyers decided
we couldn‟t use it, and therefore we wouldn‟t impact the
rest of the stack.
– But, all in all, it handled ASN.1 BER data pretty well.
UoC j.AgentX
– Bit of a student project, shall we say
– Lots of examples of Java coding
– At times, it would almost work
– Got a serious refactoring
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Serious Refactoring
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And then
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Having gotten the SNMP framework in place in the Stack, along
with a simple SNMP Master in the Simulator Platform, we had
to add the ability to register MIBs with that framework.
There is a function in MIBRouter that can add OIDs to the
router, but they don‟t quite support query, table indexing etc.
So, in a slightly more serious vein, here‟s how to add your own
data sources.
But first a slight detour...
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Block Diagram
Register API
Get/Set API
Query API
App
Stack MIBs
SNMP-Proxy
SNMP-Query
AgentX Subagent
SNMP
Java Stack
JNI interface
AgentxRegister
AgentxGet/Set
SNMP Get/Set
JAVA
C
MPE
MPE MIBs
SNMP Get/Set
AgentX Master
SNMP Server
DOCSIS
Net-SNMP
Platform
AgentxRegister
AgentxGet/Set
Agentx-Subagent
Platform MIBs
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The Objects you can use
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A Leaf Handler
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A Leaf Handler is one that supplies a single value for a single
OID
– Each OID is treated independently
– You can‟t provide the base-OID of the group and have the
framework pass all requests to you
The ABC LeafMIBModuleHandler provides the base
functionality; your class must provide
– SNMPResponse processGetRequest(SNMPRequest r)
– String[] getOIDs()

You should also implement MIBModuleHandler as that is
used in dynamic registration
– registerMIBObjects()
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Currently, Leaf Handlers are Read Only handlers as there are
no MIBs that can be set within the Stack.
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processGetRequest(SNMPRequest r)
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This simply passes the SNMP Get request to your handler.
You find the OID requested from
– r.getMIBObject().getOID()
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You return the value as an SNMPResponse
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getOIDs()
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Simply return an array of all the OIDs your handler satisfies.
When a request comes in to the framework, this tests to see if
the OID is handled and if not, will be rejected.
Therefore you know that the OID provided is one you support.
The array can have gaps where OIDs have been deprecated.
– But remeber, the „gap‟ OID will never reach your
processGetRequest() as it is tested in the framework
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registerMIBObjects()
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We‟ll come back to this, but this called by the SNMP Manager
framework when the settop starts.
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A Table Handler
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Another abstract class within the framework is
TableMIBModuleHandler which extends
LeafMIBModuleHandler
Unlike LeafMIBModuleHandler it has a constructor like this:
TableMIBModuleHandler(String rootOID, String[] colOIDs)

The rootOID specifies the base OID and the colOIDs specify
all the columns within that table
– This is to allow gap OIDs to be handled by the framework
– But! The OID must be a complete OID, not just that from
the Root OID
– I messed with the signature to make it fit...
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Again you must implement processGetRequest() as it is
possible to query a table for a definite value.
The is no need to implement getOIDs() as the base class
now implements this.
You will need to implement the interface MIBModuleHandler
for registration purposes.
The new abstract method in this class is
processGetNextRequest(MIBObject o)
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processGetNextRequest(MIBObject o)

Again an SNMPResponse is returned however:
– The OID in the response is the full OID of the element
– If the end of table has been reached you must return
END_OF_MIB_VIEW
• We have an easy way of doing this
– You can use the base class method
getNextOIDDetails(String ) to get the column and
row of the request; even if the request was for the base
table OID
– The framework will reject GET requests that do not have an
entry, row and column
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Helpful Classes
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Throughout the Stack we use a base class SNMPValue
– A simple wrapper of the Drexel SNMPObject class
– Derived classes include
• SNMPValueInteger
• SNMPValueOctetString
• SNMPValueGuage32
• SNMPValueIPAddress
• SNMPValueError
SNMPValueError is a very useful class that allows you access
to standard values for [e.g.]
– „End of Mib View‟ [a table is complete]
– „No such Instance‟ [a bad index]
– „No such Object‟ [a bad OID]
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
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The standard return value is SNMPResponse, but there is also
an extended class SNMPResponseExt
This is very handy as we can construct an SNMPResponse via
an SNMPResponseExt and a class derived from SNMPValue
return new SNMPResponseExt(new SNMPValueInteger(52));
return new SNMPResponseExt(SNMPValueError.END_OF_MIB_VIEW);
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Startup
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When the SNMP system starts up it looks for, and registers,
MIB handlers. Here‟s how.
The property files [base, hn, dvr etc] are scanned for a
property that looks like:
OCAP.MIBHandlers.eas=
org.cablelabs.impl.manager.snmp.EASMIBModuleHandler
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Where eas is just a unique identifier. It could easily be a
number, but that makes extensions difficult.
It then tries to create the class specified, cast it to
MIBModuleHandler and then call the
registerMIBObjects() method on that instance.
The instance should call MIBManager.registerOID() to
register the leaves and tables it supports.
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Just when you thought it was safe...
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Cast your minds way back to Slide 6...
We said that the Drexel SNMP library happily supported ASN.1
BER encoding.
In fact, because we have used SNMPValues throughout the
code, you can easily get the BER of a value.
Sadly, the OCAP spec for MIBObject was a little open to
interpretation and in some cases the methods
– MIBManager.queryMibs()
– MIBManager.setMIBObject()
are assumed to take only the V of the TLV in ASN.1 BER.
This means we are returning data that some applications can‟t
understand. Or that when they attempt to return or set values,
the value cannot be encoded and Exceptions are thrown.
This needs fixing for legacy applications and dual deployment.
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... you can go back in the water soon
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Solutions:
– Inter-application MIBs can be encoded as Opaque
– Stack [or Platform] sourced data can be transcoded
– SNMP Master Writes and Reads can be transcoded
– Application Writes to Stack/Platform will need adaptation
Three Phases:
– Phase 1
• Inter-application - Based on registrant type
• Application read from Stack - Based on source
– Phase 2
• Application write to Stack – Based on GET/SET
– Phase 3
• Heuristic approach for apps that support TLV
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Questions
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Thanks to
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
@ NDS
– Alan Glynne Jones
– David Brockhurst
– Kevin Hendry
– Krushna Reddy
– Laurentiu Dragan
– Madhusmitha Gottipati
– Mark Orchard
– Mike Ertl
– Nitha Ponnanna
@ Cablelabs
– Steve Maynard
– Marcin Korzen
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Real World Issues
CableLabs and NDS
working together
© NDS Ltd 2010. All rights reserved.
An Example
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Recently a defect was raised detailing that the Stack should
wait for an event from the Platform.
This was raised as OCAP_RI-505
– http://java.net/jira/browse/OCAP_RI-505
– The problem was TSB conversion could start before the
Platform had filled the buffer, leading to occasional failure
after a reboot or power cycle.
Before implementing the change we had to ensure that all
Vendors produced the event when recording data.
Although it seemed obvious that this should happen, it‟s always
best to check.
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Another example
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At times Vendors will find defects, or propose enhancements,
that come with a ready made patch.
For example Home Networking issues, OCAP_RI-487:
– http://java.net/jira/browse/OCAP_RI-487
– Couldn‟t retune to encrypted channel when recording
When this happens, NDS will
– Test the fix against the reported defect
– Apply the patch to the current CableLabs 1.1.4 code
– Submit the patch to CableLabs and wait for release
Sometimes the patch is too late, or not applicable to the
CableLabs code.
– Here NDS will incorporate the patch into their own
distribution
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Finally
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NDS tries to keep Vendors aware of up-coming changes to the
MPEOS interfaces.
This is so they can be ready to implement changes when the
code is released.
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