ITCamp 2012 - Raffaele Rialdi - Introduction to WinRT

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Introduction to

Windows Runtime (WinRT)

Raffaele Rialdi

@raffaeler

[email protected] http://www.iamraf.net


Mobile &

Development ITCamp 2012 sponsors


Mobile &

Development

• You already heard about

– «Tailored User eXperience»

• Inspiring confidence, Fast and fluid, Touch-first, Immersive,

Engaging and Alive, Connected

– Why current applications does not fit the new market

• We will dig into:

– What is the Windows Runtime (WinRT)

– Why Win8 is not a simple UI restyling

– What are the pillars (from a developer point of view)

– How can you get it to the max

Agenda


Mobile &

Development

• Procedural languages have no implicit lifetime

concept

– malloc free, CreateFile CloseHandle, …

• In .NET, Dispose pattern is a partial solution

– It's not automatic

– Can lead to resources leak

• Requires PInvoke for accessing C-Libraries

• Communication between processes is done via IPC

and not between components

OO vs not-OO


Mobile &

Development Windows Runtime Architecture

Metro apps Desktop apps

Windows Runtime APIs and Services

Win32

Language Projections

.NET / Js / C++

XAML DirectX HTML HTML WPF SL Win form

MFC

DX

.NET / Js / C++

Windows Kernel Services

Win32 XAML Pickers … Network

UI Controls Media Storage

Windows Metadata

Windows Runtime Core

Runtime Broker

Filtered access to WinRT

BCL / libraries


Mobile &

Development

• It's the evolution of Component Object

Model (COM)

– Easier

– Totally different Type System

– Same metadata of the .NET Fx (ECMA-335)

• WinRT and CLR talks the same "language"

• No marshalling gotchas

• It's not a replacement for the CLR

• CLR is required for managed languages

infrastructure

What is the Windows Runtime


Mobile &

Development Reference Count VS Garbage Collector

• Circular references • GC finds can find them as it freeze the app and search the roots

• Reference Count is autonomous and it can't

• In the new C++11 standard we have weak references

A B

Root

Parent

Parent

A B

Root

Parent


Mobile &

Development WinRT Type System

• Basic types - bool, integers, floats, enum, guid, type, object

• Strings - binary compatibile with .NET (string) and C++ STL (wstring)

- are immutable

- are value-types (non-nullable)

• There are Reference Types - All types that implement WinRT interfaces

• There are Value Types - All the others … for example arrays and structures

- Structures can't declare reference (deep/shallow copy problem)

• "Complex" types - Vector (collection) and Map (dictionary)

- Vector<T> implements IObservableVector<T> that is mapped to INotifyCollectionChanged


Mobile &

Development Language Projections

•Projections map WinRT types to the projected language

• Different casing standards - Javascript (camelCase), C++ and .NET (PascalCase)

• Developers need to understand edge-cases - Javascript standard only support IEEE-754 (floats).

This means the max integer is 53 bit maximum

• Few types are defined both in WinRT and .NET - They are treated as 'special' and seen as equivalent

- INotifyPropertyChanged, INotifyCollectionChanged, …

• Some .NET types cannot be mapped transparently - Streams, Buffers, Tasks are mapped via extension methods

• I expect third party projections too - Java?, Python?, D language?, Delphi?, …


Mobile &

Development

Class Catalog

Explorer.exe

Activation System

Activate RPCSS

DCOM Launch

Application.exe

Application Activation


Mobile &

Development Contracts : «XXI century's clipboard»

• A standard way to "talk" to other Apps or OS services

• A sort of publisher / subscriber pattern

• Main Contracts available:

• Search, Share, Protocol, PlayTo, App to App picking

• WinRT activate Apps that expose Contracts

• Running Apps is done via Launch Contract

• Tiles are NOT shortcuts!

• Apps use the Manifest to opt-in for Contracts

• They receive parameters in the activation method


Mobile &

Development Asynchronous by design

• Special objects wraps Asynchronous Operations

• In WinRT they implement IAsyncOperation<T>

• AsTask extension method is used to convert it to a Task<T>

• In .NET these objects are Task<T>

• AsAsyncOperation extension method to obtain an IAsyncOperation<T>

• C# 5.0 have new async/await keywords

• Javascript and C++ can use "promises" pattern

Problem: Apps should never block UI thread

Solution: API that may take more than 50ms are only async


Mobile &

Development Application lifecycle

• Suspension happens after ~5s the App is not visible

• Suspension message is used to save App state

• Resume happens when user switch to the App

• Typically used to refresh data from sensors, WS, …

•There is no notification for the close transition

• App state is already saved during suspension

App is

Activated

Process in

Active state

Suspend Process

in Suspended state

Low Memory (system)

App is

closed Resume


Mobile &

Development

Marketplace

The sandbox

Application Package

WinRT

Windows Kernel Services

Win32

Security Broker Proxy

Libraries

White-listed

Manifest

Application code


Mobile &

Development Developing with WinRT • XAML UI for .NET and C++

• XAML / DirectX can share surfaces • DirectX inside a XAML control

• Large virtual DirectX surface in conjunction with XAML

• High Performance DirectX drawing, XAML overlapped

• Custom WinRT components are easy to write • i.e. exposing C# or C++ code to Javascript or vice-versa

• Custom components are private to the App (no RegSvr32)

• Cross language calls are cheap • No more P-Invokes!

• As fast as a vtable call

• Desktop Apps can use a WinRT APIs subset

• CLR have an additional weapon: "Portable Class Library" • A DLL with code that run on Metro, desktop, SL, …

• As it's IL code, it runs as 32 or 64 bits as well


Mobile &

Development Metro profile for .NET development

• What else is not in the Metro profile?

• APIs that are already in WinRT (Storage, Sockets, Network, etc.)

• Server libraries like WCF, Asp.net, …

• APIs that could bypass the sandbox • System.Data, Remoting, AppDomain, Private Reflection, …

Metro Fx 4.5 WP7

# assemblies 15 120 22

# namespaces 60 400 88

# types ~1'000 ~14'000 ~2'000

# members ~10'000 ~110'000 ~14'000

Metro profile was a good opportunity to clean BCL • Removed: Xml DOM, WebClient, Threads, … • Moved Reflection in System.Reflection

• GetTypeInfo extension method to access reflection classes


Mobile &

Development Developer thoughts

• No need to elevate (UAC) a Metro App • Admin Apps will run in the old desktop

• Storage • Apps can access only locations specified by manifest

• Users can pick (via UI) a file that is stored elsewhere

• No local db APIs at the moment

• Media and Sensors • Easy access to cameras, accelerometer, …

• Require user consent (requested via manifest)

• Network • Great library to ease oAuth authentication

• Flexible HttpClient replace WebClient

• Websockets support

• Dig into the APIs and discover it by yourself!


Mobile &

Development Takeaways

• WinRT is a great step in Windows evolution

• Exposes native OS services in a pure OOP way

• Closes the gap between managed and native

languages

• Developers can use their current knowledge to

create Apps from small devices to classic PCs

• Marketplace is an opportunity for developers

and a sweet experience for end-users

• Think about performance/battery issues

• It's Framework.NET best friend


Mobile &

Development Tools for WinRT

• WinRT.codeplex.com

• Debug Activation, WRL project template, ... (more to come)


Q & A

ITCamp 2012 - Raffaele Rialdi - Introduction to WinRT

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