% title: Eclipse Plug-in Development % title_class: #empty, largeblend[123] or fullblend % subtitle: Extending the CDT Debugger % author: Marc Khouzam % author: Marc-André Laperle % thankyou: Thank you % thankyou_details:

title: Agenda class: nobackground build_lists: false content_class:

Day 1: Plug-in development
- Module 1: Eclipse Platform and plug-in development
- Module 2: Implementing a first plug-in
Day 2: Getting to know DSF
- Module 3: DSF concepts and exercises
- Module 4: DSF events and exercises

title: Other content available but not covered build_lists: false

Getting to know DSF-GDB
- Module 5: DSF-GDB concepts and exercises
Modifying DSF-GDB's behaviour
- Module 6: Changing the Debug View
- Module 7: Changing GDB's initialization
  
  ##Let's get started! [//]: (This is a comment)

title: Approach to course

A mix of theory and hands-on exercises
Teams of 2
Ask questions often and give feeback
9h30 to 16h30 schedule
One hour lunch
15 minute break, morning and afternoon
Please tell us if you are confused during the course

title: Start your Eclipse

Execute the start script ~/workspace-training/start.tcsh
All good?

##

Plug-in development

title: Module 1 subtitle: Eclipse Platform and Plug-in Development

Intro to Eclipse Platform
Plug-in development

title: The Eclipse Platform

Frameworks and Common services for:

Rich Client Platform (RCP)
Tool integration

Examples of rich client applications:

Eclipse for Java Developpers, Eclipse SDK, Stand-alone C/C++ Debugger, Trace Compass, etc.

Examples of tool integrations:

CDT, EGit, Trace Compass plugins

title: The Eclipse Platform

title: Eclipse Runtime

Mainly composed of the Eclipse Equinox project.

Eclipse Equinox:

Implements the OSGI specification (modules, services, etc)
P2: Provisioning framework. Installs new plug-ins, resolves dependencies, etc.
Miscellaneous Core functionallity like the extension registry (plug-ins), Jobs, Preferences, etc.
Eclipse launcher (native)

title: Workspace

The workspace is a view of the user's data files: the resources.
Types of resources: projects, folders, and files
Only one workspace per running platform
Structure: Workspace root > Projects > IFolders or IFiles
Common classes:
- IResource
- IWorkspace
- IFile
- IFolder
- IProject
Resource names and their paths in the workspace to not have to match the location on the filesystem

title: Workspace

Other features than navigation/listing:

Markers: to display problems like compilation errors
Properties: per-file storage. Think flags like "read-only" but more customizable.
Virtual folders: for greater flexibility when organizing projects
Project natures: to differentiate between different kind of projects (Java, C/C++)
Resource deltas: Listen to file modification, creation, deletion, etc.

title: EFS

Eclipse File System (EFS).

An abstract file system API
The Workspace resources sit on top of EFS
The default implementations is for Local file systems
Other implementations: SSH, FTP, dstore, ZIP, etc.

title: Eclipse Team

Framework to integrate SCMs.

Repository configuration
Resource management: Hooks for delete, move, add. Decorators in the UI.
Synchronization: tracks whether or not resources are in sync. Local history.
Logical Model Integration: Operate at the model level instead of per-file.
Views: Synchronize, History, etc.

EGit, CVS, Subversion, Perforce use this.

title: Eclipse Help

Table of content, Search, indexed
Context sensitive (F1). Plug-ins can set context "ids"
Runs on a local server, either in internal browser (SWT wiget) or external

Other "User Assistance" features

Cheat cheets
Welcome page
Tutorials

--- title: SWT

Standard Widget Toolkit (org.eclipse.swt.*)

A Java library of widgets aimed at providing efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.

This is typically the lowest level of UI programming done in Eclipse development.

title: SWT subtitle: Features

Native look
Quite fast!
Button, Text, Browser, Group, Table, Tree, etc.
Parent is specified in constructor (versus add child to parent container explicitly)
Can be used as a stand-alone Java library (without anything else Eclipse)

title: SWT subtitle: Implementation

Single UI thread
Implemented using JNI calling the OS native library (which means SWT has some native glue code)
- Windows: Win32
- Mac: Cocoa
- Linux: GTK2 and GTK3
Browser widget is integrated with different libraries: Webkit, Internet Explorer, XULRunner (Firefox)
Most crashes (i.e. segmentation fault) in Eclipse due to native libraries called by SWT
- GTK, WebKitGTK+, Ubuntu-specific libraries (Unity)
A bit hard (but fun) to debug. Java + Native C

title: JFace

JFace is a UI toolkit with classes for handling many common UI programming tasks. It is designed to work with SWT without hiding it.

org.eclipse.jface.*

Common uses:

Viewers: TreeViewer, TableViewer, etc.
Dialogs: Message dialog, error dialog, etc.
Wizards: Wizard dialog, pages

title: Workbench

org.eclipse.ui.*

This is where classes more related to the common IDE UI fonctionality reside.

title: Workbench

A Workbench has one or more workbench windows.
Each Workbench Window has workbench pages.
Each Workbench Page has workbench parts, of which there are two kinds: views and editors.
Each Workbench Part is either a View or an Editor.

title: Workbench

Common uses:

Views: IViewPart and the extension point org.eclipse.ui.views
Commands and Handlers: org.eclipse.ui.commands, org.eclipse.ui.handlers extension points.
Preference pages: org.eclipse.ui.preferencePages extension point
Editors: org.eclipse.ui.editors extension point. IEditorPart and useful classes like TextEditor

title: The Eclipse SDK

To be able to work with the Eclipse Platform, you need tools.

=+

The Eclipse SDK = Platform (including source) + JDT + PDE

title: JDT: Eclipse Java development tools

Those are the tools suitable for any Java-based programming

title: PDE: Plug-in Development Environment

Provides tools to create, develop, test, debug, build and deploy Eclipse plug-ins.

title: Module 2 subtitle: Implementing a First Plug-in

title: Project for exercices

We will create a new view that will display a log. Every time the debugger stops, print function:linenumber.

--- title: What IS an Eclipse plug-in?

It's an OSGI bundle, a java module. But with an Eclipse flavor. Among other things:

Specifies dependencies to other plug-ins
Uses extensions to plug into existing extension points
Can define new extension points for others to extend
Specifies what to package in the (Jar)
Specifies the execution environment (Java 7, 8, etc).

Difference between extension and extension point?

Extension = plug
Extension point = socket

A lot of things are done through extension points. For that, we need a plug-in.

title: Exercise: Create a plug-in

Go to Plug-in Development perspective
File > New > Plug-in project
Name your plug-in (org.eclipse.cdt.example.framespy)
Press Next then Finish
Go!

What are all the tabs for?

title: Step to prepare

Since we want to use the Git repo, delete the project and import existing one.
- Right-click on your project and press Delete then press OK

title: Step to prepare (2)

Go to Plug-in Development perspective:
- File->Import...->General->Existing Projects into Workspace
- Press Next
- Press Browse...
- Choose ~/workspace-training/EclipseTraining/org.eclipse.cdt.example.framespy
- Make sure a single project is showing and is selected
- Press Finish
Right-click on project and choose Team->Fetch from Upstream

title: Exercise: Create a view

Reset to PLUG1
Add a new view by adding an extension (plugin.xml)
Create the view class (tip: click the hyperlink to bring up the New Class wizard)
Make sure the view has an id, name
To test your progress

Go!

title: SWT Basic widget creation

Text textBox = new Text(parentComposite, SWT.SOMESTYLE | SWT.OTHERSTYLE);
textBox.set*Somesetter*
textBox.add*Somelistener*

Composite are containers of widgets that can be layed out.

Composites can be in composites!

title: Exercise: Add button to view

Let's add a Button. Let's make it a checkbox button.

Reset to PLUG2
In view class, in createPartControl() add new Button with a "checkbox style"
Add selection listener to detect when it's pressed
Output something to the console
Go!

But the button does not belong in view itself, it would be nicer in the toolbar.

title: Eclipse commands and handlers

The Commands framework is a way to add user actions to the user interface. A command has:

An id that declares a semantic behavior
One or more handlers

For example, the Copy command has the id org.eclipse.ui.edit.copy. But it has many handlers that behave differently depending on the context (selection, view)

title: Exercise: Create the command and handler

Reset to PLUG3
Add a command extension to toggle log on/off
Create a defaultHandler class (tip: use hyperlink to create class). Make it extend AbstractHandler (the one in 'core')
Implement the execute method to make it print something to the console
Go!

title: The menus extension point

The org.eclipse.ui.menus extension point can add commands to:

Main menu (menu)
Main toolbars (toolbar)
View context menus (popup)
View toolbars (toolbar)
View menus (menu)

It has an odd locationURI field: [Scheme]:[ID]?[placement]

For example:

menu:org.eclipse.ui.main.menu?after=additions

title: Exercise: Add toolbar button

Let's add the command to the view toolbar.

Reset to PLUG4
Create the menus extension (Extension tab, org.eclipse.ui.menus extension)
Add a menuContribution, set the locationURI so that it gets displayed in the view toolbar, after additions
- locationUri: toolbar:my.view.id?after=additions
Right-click on menuContribution, Add a command. Set the id, icon and style
- id: the id of your command
- icon: enablespy.gif
- style: push
Go!

It would be nice in the context menu as well.

title: Exercise: Context menu

Let's add the same command in the context menu.

Reset to PLUG5
Add a new menuContribution (right-click on org.eclipse.ui.menus). Because it needs different locationURI.
- locationUri= popup:my.view.id
Add the command (right-click on menuContribution). Set the id, icon and style (push)
Create a context menu in the view, to be populated:

// put in createPartControl
fMenuManager = new MenuManager();
Menu menu = fMenuManager.createContextMenu(composite);
composite.setMenu(menu);
getViewSite().registerContextMenu(fMenuManager, null);
...
// put in dispose (override the method)
fMenuManager.dispose();

Go!

title: Exercise: Show the toggle state

The user needs to see whether logging is enabled or not.

Let's add a label that displays that.

Reset to PLUG6
Add a Label (a SWT widget) at the view creation.
- Label label = new Label(c, SWT.NONE)
- label.setText(Boolean.FALSE.toString());
When the command executes:
- Set the toggle state (you can add a method to the view)
- In the handler, get the view with FrameSpyView part = (FrameSpyView) HandlerUtil.getActivePartChecked(event);
- Update the label text
  - label.setText
Go!

If you enable logging and close/reopen the view, what happens?

title: The Preference Store

We should make sure that the toggle state is remembered when the view is closed (or Eclipse is restarted). There are multiple ways to do this. A useful one is the Preference Store.

Works like a key/value map
Can be applied to different scopes:
- DefaultScope: When the user presses "restore defaults" it restores to this.
- InstanceScope: Saved at the workspace level. Overrides Default.
- ProjectScope: Saved at the project level. Overrides Instance.
- Custom!
Organized in nodes (think namespaces). Typically the plug-in id.

title: Exercise: Persist the toggle state

Reset to PLUG7
When the toggle state is set:
- Get the InstanceScope
- Get the node
- Set the key/value

Saving the preferences in our FrameSpyView.togleState method

IEclipsePreferences preferences = InstanceScope.INSTANCE.getNode(Activator.PLUGIN_ID);
preferences.put(TOGGLE_STATE_PREF_KEY, Boolean.toString(fToggledState));

title: Exercise: Persist the toggle state

When the view is created:
- Get the InstanceScope
- Get the node
- Get value using key, set the label text

IEclipsePreferences preferences = InstanceScope.INSTANCE.getNode(Activator.PLUGIN_ID);
preferences.get(TOGGLE_STATE_PREF_KEY, Boolean.toString(false)); // set to false in case it was never set

Go!

title: Eclipse Jobs

Jobs are similar to Java Thread but have Eclipse flavor.

Some differences:

Scheduling rules: determine which jobs can run concurrently
Deadlock detection: and recovery (ILock)
Shown in the Progress View to the user (or not) with progress (IProgressMonitor)
Can be made cancellable by the user
Returns a status (IStatus)

In Eclipse code, Jobs and Threads are both commonly used, depending on the situation.

For the first implementation of our logging feature, we will poll every one second using a job.

title: Eclipse Jobs

job = new Job("Frame Spy Polling Job") {
	@Override
	protected IStatus run(IProgressMonitor monitor) {
		return Status.OK_STATUS;
	}

};
job.schedule();

title: Exercise: Creating a polling job

Reset to PLUG8
When toggle state is on, create and schedule a job. Store it in a field (fJob).
- Give the job a nice name to be shown in the Progress View
In the job run() method, sleep for 1 sec. Use Thread.sleep
After the 1 sec, reschedule the job (only if the toggle state is still on!). Use schedule()
Print something to the console every tick "polling..."
If the toggle state becomes 'off' cancel the job. Use fJob.cancel().
Go!

title: Exercise: Print to view

Every tick, we would like to show the elapsed time in the view. It can just be an incrementing counter.

Reset to PLUG9
Create a counter (a simple int) that is incremented each tick.
Set the text label with the value of the counter
Go!

What happens?

title: SWT Display and the UI thread

Changes to the UI (widgets) should always be done on the UI thread.

The Display implements the event loop. There is only one instance in a running Eclipse.

Display.getDefault().asyncExec // Execute code at the next reasonable opportunity. Caller continues in parallel.
Display.getDefault().syncExec // Blocks calling thread until executed on UI thread

With this knowledge we can fix the Invalid Thread Access. We can use asyncExec in this case. (PLUG10)

title: Exercise: Handle cancel

An IProgressMonitor is passed to the job.

We can use it to know if the user canceled the logging.

Reset to PLUG10
Use monitor.isCanceled() to know when user canceled
Set the toggle state to off when canceled
Go!

What happens? Do you have a problem with the job starting again? If you need results from UI thread right away -> syncExec

title: Exercise Review subtitle: What we accomplished

Create a plug-in
- File > New > Plug-in project

title: Exercise Review (2) subtitle: What we accomplished build_lists: false

Creating a view
- extension point="org.eclipse.ui.views"
- Extending ViewPart and filling createPartControl()
Using SWT widgets
- Using Button, Label
- Using the UI Thread for such things
- Display.getDefault().syncExec()/asyncExec()

title: Exercise Review (3) subtitle: What we accomplished build_lists: false

Using commands, handlers and menus
- extension point="org.eclipse.ui.commands"
- Extending AbstractHandler#execute() to do the work of the command
- extension point="org.eclipse.ui.menus"
  - toolbar:org.eclipse.cdt.example.framespy.view?after=additions
  - popup:org.eclipse.cdt.example.framespy.view
- Initializing a context-menu using MenuManager

title: Exercise Review (4) subtitle: What we accomplished build_lists: false

Using the preference store
- InstanceScope.INSTANCE.getNode(PLUGIN_ID)
Using Jobs and Progress Monitors
- Job#schedule()
- monitor.isCanceled()

##

Getting to know DSF

title: Module 3 subtitle: DSF Concepts and Exercises

Eclipse Debug Platform
What is DSF?
DSF concepts applied
DSF Exercise 1

title: Building on our new view

Debug Frame Spy
- New view logging each method:line at which the debugger stopped.

title: Debug Frame Spy Details

Show list of method:line of each location the program was interrupted
Show time of interrupt for each entry
Show the number of arguments of the function for each entry

title: Eclipse Debug Platform

Eclipse provides a foundation for Debugging
- Debug perspective
- Debug views
- Debug Actions, Toolbar, Menus
- Debug Launching

title: What is DSF?

Overview
View Model and Data Model
Services
Data Model contexts
DSF Executor thread
DSF Session
Asynchronous (callback) programming

title: DSF Overview

API for integrating debuggers in Eclipse
Also designed for efficiency (slow or remote targets)
Figure shows typical debugger integration using DSF

title: View Model

View Model provides layer of abstraction for views
- User-presentable structure of the data
View Model allows to easily modify presentation e.g.,
- Hide running threads
- Limit number of stack frames
- Only show processes if there is more than one

title: Using the CDT Debugger

Start your test Eclipse
Use the debug icon to debug a C program
Step, look at variables, set breakpoints, resume

title: Data Model

Data Model deals directly with the backend debugger
- Natural or backend structure of the data
- Independent of presentation to user
- Provides building blocks for the view model
- Uses common debugger concepts
  - Execution elements (e.g., processes, threads)
  - Formatted values (e.g., variables, registers)
  - etc

title: DSF Services

DSF provides a service API to access the Data Model
Built on top of OSGi (as Eclipse is)
Services are entities managing logical subsets of the data model
Services are used to request information or to perform actions

title: DSF Services (2)

For example, the IRunControl service:
- Provides list of execution elements (e.g., threads, processes)
- Provides details about such elements (e.g., name, state)
- Supports step, resume, interrupt, etc
Other services: IMemory, IRegisters, IExpressions, IDisassembly...
All services extend IDsfService (press F4 on IDsfService)

title: Data Model Contexts

IDMContext class is a 'pointer' to any type of backend data
- IExecutionDMContext - thread, process, group
- IFrameDMContext - stack frames
- IBreakpointDMContext - breakpoint, tracepoint, dprintf
- All contexts extend IDMContext (use F4)
Contexts are hierachical
- process -> thread -> frame -> expression
- DMContexts.getAncestorOfType()
Contexts are used to retrieve data from services

title: DSF Executor thread

Accessing data from different threads requires synchronization
DSF uses a single-threaded executor to avoid synchronization

title: DSF Session

Instances of DSF services are grouped into a DSF session
There can be multiple sessions running at the same time
The session provides the DSF Executor (DsfSession#getExecutor())
A session handles sending events to registered listeners

title: Asynchronous (callback) programming

Most DSF APIs return void but indicate completion in a callback
RequestMonitor is the main callback class
- Remember to call done() when real work is finished
- This calls: handleCompleted(), handleSuccess(), handleError()
DataRequestMonitor to "return" a value
- getData() to get that value

title: RequestMonitor example

To call an asynchronous method, such as:

void asyncCall(IDMContext dmc, RequestMonitor rm);

there are two main coding styles:

Declarative:

   RequestMonitor myRm =
           new RequestMonitor(getExecutor(), parentRm);
   asyncCall(dmc, myRm);

In-line:

   asyncCall(dmc, new RequestMonitor(getExecutor(), parentRm));

title: Declarative Style

First declare the RequestMonitor and what it should do
Then call the asynchronous method, passing the RM

   RequestMonitor myRm =
           new RequestMonitor(getExecutor(), parentRm) {
               @Override
               void handleSuccess() {
                   System.out.println("Async call succeeded");
                   parentRm.done();
               }
           };

   asyncCall(dmc, myRm);

title: In-line Style

Directly call the asynchronous method
Declare and define the RM in-line

   asyncCall(dmc, 
             new RequestMonitor(getExecutor(), parentRm) {
                 @Override
                 void handleSuccess() {
                     System.out.println("Async call succeeded");
                     parentRm.done();
                 }
             });

In-line has the benefit of showing the execution flow

title: DataRequestMonitor

Extention of RequestMonitor which "returns" data

   DataRequestMonitor parentRm =
              new DataRequestMonitor(getExecutor, null);
   asyncCallWithData(
      dmc, 
      new DataRequestMonitor(getExecutor(), parentRm) {
      @Override
      void handleSuccess() {
          String resultString = "Success with result " + getData();
          parentRm.done(resultString);
      }
   });

title: Other RequestMonitors

CountingRequestMonitor and MultiRequestMonitor
- For multiple asynchronous request in parallel
ImmediateRequestMonitor and similar
- handleSuccess() and others are called on the thread where the ImmediateRM was created.

title: DSF concepts review build_lists: false

APIs to integrate a debugger 'more easily' e.g., GDB
View Model for presentation layer
Data Model to communicate with backend (GDB)
Services API to access Data
No synchronization: DSF Executor must be used to access Data
Services for one backend are grouped in a Session
Heavy use of asynchronous programming for responsiveness

title: DSF practical review build_lists: false

Services extend IDsfService
Contexts extend IDMContext
Context hierarchy searched with DMContexts
Executor can be found with DsfSession#getExecutor()
RequestMonitor and DataRequestMonitor for callbacks

title: DSF Exercise build_lists: false

FrameSpy to periodically print "method:line" for current frame
- Reset branch to commit starting with
  - DSF1_START or DSF1_ADVANCED
- To test, make sure you launch a C/C++ Debug session first
- Use the Tasks view to see what needs to be done
- Go!

title: Exercise review build_lists: false

Finding the DSF session using debug context
- Debug View and Debug Context
- Adapter pattern
Calling an existing DSF service
- Using a DsfServicesTracker for the DSF session
Call the asynchronous IStack.getTopFrame()
- Using a new DataRequestMonitor
- Calling getData() in handledSuccess()

title: Exercise review (2)

IDMContext vs IDMData
- call IStack.getFrameData()
- Using a new DataRequestMonitor
- Calling getData() in handledSuccess()
- Then finally display "method:line"

title: Exercise follow-up part 1 build_lists: false

What if you select the process element?
- The top frame of which thread should we use?
For now, just handle the error (as seen on console)
- Reset to DSF1_ANSWERS if you need
- Override handleError()
- Go!

title: Follow-up part 1 review

title: Exercise follow-up part 2

Assertions are a great way to notice unexpected situations
Enable assertions in development eclipse for test eclipse
- In launch configuration, Arguments tab, VM arguments
- Add -ea
- Make sure you have a breakpoint for AssertionError
- Re-launch and try
- Go!

title: Exercise follow-up part 2

Did you use the DSF Executor?
- Which code runs on the Executor, which not?
Wrap first call to DSF service in Executor
- Call submit() of the Executor
- Pass a DsfRunnable() whose run() does the work
- Go!

title: Follow-up part 2 review

title: Module 4 subtitle: DSF Events and Exercises

What are DSF events
Sending and receving DSF events
DSF Exercises 2 and 3

title: DSF Events

DSF uses events to notify listeners of different things e.g.,
- Thread/Process started/exited
- Thread/Process suspend/resumed
- Breakpoint added/updated/removed
- etc

title: DSF Events (2) build_lists: false

Events are how the Data Model tells the View Model of changes
- e.g., Thread stops => Update Debug View
- View Model is an advanced topic not covered in this course
Events also notify services of other services' changes
- e.g., Clearing caches when execution resumes

title: DSF Events details

Most events implement IDMEvent which provides an IDMContext
- e.g., When thread suspends, event specifies which thread
Event types usually found in the different service interfaces e.g.,
- IRunControl:
  - ISuspendedDMEvent, IContainerSuspendedDMEvent
  - IResumedDMEvent, IContainerResumedDMEvent
Not all services trigger events
- IStack has not events

title: Sending DSF Events

To send an event a service calls DsfSession#dispatchEvent()

title: Receiving DSF Events

To receive a DSF events a client must:
- Declare a public method of any name
- Method takes the event of interest as a parameter
- Annotate method with @DsfServiceEventHandler
- Register with the DSF Session using DsfSession#addServiceEventListener()
- Registration must be done on the Executor
The method is called on the DSF Executor

title: Receiving event example

The following method from SomeClass will be called for every suspended event

    @DsfServiceEventHandler
    public void anyName(ISuspendedDMEvent e) {
        System.out.println("Received " + e.toString());
    }

as long as we register the class with the session

    getSession().addServiceEventListener(SomeClass.this, null);

Remember that registration must be done on Executor

title: Help with the Executor build_lists: false

DSF provides Java Annotations to guide with Executor use
- @ThreadSafe
  - Safe for any thread (synchronization used)
- @ConfinedToDsfExecutor(executor)
  - Must use specified executor
- @ThreadSafeAndProhibitedFromDsfExecutor(executor)
  - Safe for any thread except the specified executor
They are hierarchical, so apply to children (e.g., methods of class)
Unfortunetly, there is no compiler support so they are effectively just comments (that are sometimes missing)

title: DSF Event Exercise

Show "method:line" each time a thread stops instead of polling
- Reset branch to commit starting with
  - DSF2_START or DSF2_ADVANCED
  - Polling job has been removed for you
  - "method:line" only shown when FrameSpy first enabled
- To test:
  - make sure your debug session is in Non-Stop mode
  - step program and check new "method:line" each step
- Go!

title: Event Exercise Review

Registering for DSF events
- addServiceEventListener() using the Executor
- Must pass FrameSpyView.this (or another listener class)
Unregister for DSF events when FrameSpy disabled
- removeServiceEventListener() using the Executor
- Must pass FrameSpyView.this (or listener used)

title: Event Exercise Review (2)

Receiving the event

@DsfServiceEventHandler
public void anyName(ISuspendedDMEvent event) {
    // Fetch frame info and print it
}

title: Event Exercise for All-Stop

ISuspendedDMEvent is used for Non-stop only
IContainerSuspendedDMEvent for All-stop
- Represents the process stopping
- The top frame of which thread should we use?
This event specifies which thread caused the stop
- Use that triggerring thread (context)
- (Look at declaration of IContainerSuspendedDMEvent)
- Reset to DSF2_ANSWERS
- Go!

title: All-Stop Exercise Review

title: Handling a new session

FrameSpy has an important limitation now
- enable FrameSpy
- stop the session and start a new one
- step the new session
- FrameSpy no longer prints

title: Handling a new session (2)

##

Why?

title: Handling a new session (3) build_lists: false

When new session starts, we are not registered for its events
How to know when new session starts so we can register?

title: DsfSession to the rescue

DsfSession notifies registered listeners of start/end of all sessions
- addSessionStartedListener(), removeSessionStartedListener()
- addSessionEndedListener(), removeSessionEndedListener()
DsfSession provides access to all running sessions:
- getActiveSessions(), getSession(id)

title: Multiple Session Exercise

Register for event for each new DSF session
- Reset to DSF3_START or DSF3_ADVANCED
- Listen for new session and register with them
- Unregister when FrameSpy gets disabled
- Go!

title: Sessions Exercise Review

title: Final Recap

We've created a new view that used existing services
We've created a new service that the new view can use
We've created a replacement service for our own delegate

title: Module 5

What is DSF-GDB
A little history
DSF-GDB's service structure
DSF Exercises 4, 5 and 6

title: What is DSF-GDB

Integration of GDB using DSF
- Cannot use run DSF by itself
Extra features on top of base DSF
- Tracepoints
- Visualizer
- OS Resources

title: History of DSF-GDB

How it started
Ericsson's involvement
GDB's evolution
Default CDT Debugger integration
Where we stand today

title: DSF-GDB's services

DSF provides API for services
- IStack, IBreakpoints, IExpressions, etc
DSF-GDB provides an implementation
Hierarchy of DSF-GDB services
- Press F4 on IDsfService
- MI[service] vs GDB[service] (historical)
- GDB[service][version]
- GDB[service]_HEAD

title: New Service Exercise build_lists: false

Write a new service providing the current time
- Reset to DSF4_START or DSF4_ADVANCED
- FrameSpyService.java already created for you
- Make it into a DSF service that can be found by name
- Provide methods:
  - Synchronous getLocalTimeOfDayString method
  - Asynchronous getTargetTimeOfDayString method
- Go!

title: New Service Review build_lists: false

AbstractDsfService can be used as a base class for services
- Need to implement getBundleContext()
- Need to advertise a service using register()
  - Any name can be used but class or interface name is good
- initialize() and shutdown() should be enhanced
- Some method providing the service functionality is needed

title: Asynchronous vs Synchronous API

Slowest part of the CDT debugger is communication with GDB
- DSF provides infrastructure for async communication
- New async API can use that infrastructure
- New sync API cannot
Async API can be used synchronously but not other way around

title: Using new service

Prepend every printout in FrameSpyView with the time of day
- Reset to DSF4_UPDATE_START
- FrameSpyView to show: [time] method:line
- If you test it, it will not work (yet)
- Go!

title: Instantiating new service build_lists: false

We can't find the service because we didn't instantiate it
We need one instance for each DSF session
A DSF-GDB session instantiates its services
- We haven't hooked into a DSF-GDB session (yet)
- We need to manage our new service ourselves
- Remember addSessionStartedListener() and friends?

title: Instantiation Exercise

Implement a managing class to create/dispose of the new service
- Reset to DSF5_START or DSF5_ADVANCED
- Done for you:
  - Singleton FrameSpyServiceManager.java
  - initialize() and dispose() called by Activator
- Instantiate and initialize() a FrameSpyService for each new DSF session
- When done FrameSpyView should show: [time] method:line
- Go!

title: Service Shutdown

We instantiate a service for each new DSF session
What about shutting down those instances?
- Each time a DSF session ends
DSF-GDB automatically shutsdown all DSF services
- Anything registered and implementing IDsfService
- We don't need to take care of it ourselves
- Refer to DSF-GDB's ShutdownSequence.java

title: Frame Argument count build_lists: false

Provide the number of arguments when printing "method:line"
- Reset to DSF6_START or DSF6_ADVANCED
- Provide API (method) in your service for arguments count
- Async or Sync?
  - Is the info needed in GDB?
  - Are you going to call any async APIs?
- Use IStack service to get list of frame arguments
- Update FrameSpyView to show: [time] method:line (# args)
- Go!

title: Exercise Review

##

Modifying DSF-GDB's behaviour

title: Module 6 subtitle: Changing the Debug View

Extending an existing service
Launch Delegates and Launch Configuration Types
Service Factories
DSF Exercises 7 and 8

title: Building on DSF-GDB

For a new debugging feature
- Use existing DSF-GDB services
- Re-work obtained information
- Provide new information to view

title: Modifying DSF-GDB

To change an existing debugging feature
- Override View Model code
- Override Data Model code
We will focus on overriding a service (i.e., the data model)

title: Extending a service build_lists: false

For stack frames, replace method name "main" with "entry"
- Reset to DSF7.1_START or DSF7.1_ADVANCED
- FrameSpyStackService.java extends existing Stack service
- Override getFrameData()
- "Return" an IFrameDMData whose getFunction() returns "entry" instead of "main"
- Go!

title: New Service Instantiation build_lists: true

Like before we now have a new class we must instantiate
Can we use FrameSpyServiceManager?
- FrameSpyStackService extends existing GDBStack_HEAD service
- GDBStack_HEAD is already being instantiated by DSF-GDB
- Instantiating ours would create two IStack services
We need to instantiate our service instead of the original one

title: Two approaches to extend DSF-GDB

Creating a new view and a new service
- Does not affect the rest of the debugging views
- We can do this to any DSF-GDB session
- This was our first set of exercises
Replacing a service and changing an existing view
- Does affect normal debugger behaviour
- Should be chosen by user explicitly
- Aimed at specific scenarios
- This is what we need now

So, how do we replace a service?

title: First solution

New Launch Configuration Type
- Current ones i. C/C++ Application i. C/C++ Attach to Application i. C/C++ Postmortem Debugger i. C/C++ Remote Application
- Add a new one such as "IMA2l-Chip Debugger"
- Launch Config Types need a Launch Delegate
- When chosen by user, we know to replace IStack service

title: Second solution

New Launch Delegate to existing Launch Configuration Type
- Current ones for C/C++ Application i. GDB (DSF) Debug Process Launcher i. Legacy Create Process Launcher (will be removed)
- Add a new one such as "IMA2l-Chip Local Launcher"
- When chosen by user, we know to replace IStack service

title: Differences

Both solutions are almost the same
- Both need a new launch delegate
- The first also provides a new launch config type
- The second re-uses existing launch config types
Base choice on the UI presented to the user
Code differences are minor

title: Launch Delegate exercise build_lists: false

Create a new Launch Delegate for C/C++ Application
- Reset to DSF7.2_START
- FrameSpyLaunchDelegate.java extends GdbLaunchDelegate
- Update Extensions tab of plugin.xml
  - Fill-in org.eclipse.debug.core.launchDelegates
  - "Main" Launch tab has been provided for you
- Go!

title: Launch Delegate Review

When creating a "C/C++ Application" launch, we can now select our delegate
But the new delegate does exactly what DSF-GDB does
It still does not instantiate FrameSpyStackService

title: New Services Factory

Now that we have a new delegate, we can create a new Services Factory
A DSF Service Factory is used to create the different services
- Let's have a look at GdbDebugServicesFactory
When user chooses new delegate, they will get new IStack service

title: Services Factory Exercise build_lists: false

Create a new Services Factory for our Launch Delegate
- Reset to DSF7.3_START
- FrameSpyServicesFactory.java extends GdbDebugServicesFactory
- This new service factory instantiates FrameSpyStackService
- Our delegate uses FrameSpyServicesFactory
  - by overridding newServiceFactory()
- Go!
- You should be able to see "entry" instead of "main"

title: Current status

We have a new delegate FrameSpyLaunchDelegate
We have a new service factory FrameSpyServicesFactory
We have a new service FrameSpyStackService
New delegate uses new service which replaces "main" with "entry"

title: Service_HEAD pattern

Why did our new service extend GDBStack_HEAD?
Recent improvement allows extenders to stay on newest GDB version
Let's look at an example
- F4 on GDBControl_HEAD
GDBService_HEAD always points at newest service version
Favors stability of latest GDB version at the detriment of older ones

title: Launch Config Type exercise

Create a new Launch Configuration Type for our delegate
- Reset to DSF8_START
- Use extension points in plugin.xml
- o.e.debug.core.launchConfigurationTypes
- o.e.debug.ui.launchConfigurationTypeImages
- o.e.debug.ui.launchConfigurationTabGroups
- Assign our launch delegate to new launch config type
- Assign our launch tab to new launch tab group
- Go!

title: What we've seen

We've created a new view that used existing services
We've created a new service that the new view can use
We've created a replacement service for our own delegate

title: Module 7 subtitle: Changing GDB's Initialization

DSF-GDB Launch steps
Communicating directly with GDB
FinalLaunchSequence
Extending the FinalLaunchSequence
DSF Exercise 9

title: Modifying GDB initialization

DSF-GDB initializes GDB based on parameters of the launch config, e.g.,
- Enable non-stop mode
- Connect to a remote target
- Open a core file
In some situations, we may want to modify how GDB is initialized, e.g.,
- Remove step that connects to remote target
- Modify which .gdbinit file is read
- Send a new command before connecting to target

title: DSF-GDB launch steps

GdbLaunchDelegate#launch() called by platform
- FrameSpyLaunchDelegate#launch() for our extension
ServicesLaunchSequence triggered to start services
- This uses the Services Factory we saw earlier
FinalLaunchSequence triggered to initialize GDB

title: Adding a step at initialization

Goal: Turn on GDB verbosity (debug printouts) from the beginning
- Need to send GDB the MI command: -gdb-set verbose on
- Need to send it before other commands sent to GDB
Exercises:
- Provide API in FrameSpyService to send new command
- Extend DSF-GDB's initialization class: (FinalLaunchSequence)
- Use extended initialization class instead of DSF-GDB's one

title: Communicating with GDB

ICommandControl#queueCommand() used to send a command to GDB

ICommandControl#queueCommand(
            new MIExecContinue(threadContext),
            new DataRequestMonitor(getExecutor(), parentRm));

ICommandControl#queueCommand(
           new MIStackInfoDepth(threadContext),
           new DataRequestMonitor(getExecutor(), parentRm) {
                @Override
                protected void handleSuccess() {
                    parentRm.setData(getData().getDepth());
                    parentRm.done();
                }
            });

title: ICommandControl service

ICommandControl also provides APIs for:
- Getting notified of GDB commands status changes
  - Queued, Sent, Removed, Done
- Getting notified of asynchronous GDB events.
  - =breakpoint-created/deleted/modified
  - =memory-changed
  - *stopped/*running
  - etc

title: Sending a command to GDB exercise

Add a method to FrameSpyService that will send the command "-gdb-set verbose on"
- Reset to DSF9.1_START or DSF9.1_ADVANCED
- Go!

title: When to trigger this new command

We want to enable debug logs
We should send the command as early as possible

title: The ReflectionSequence class

Used by FinalLaunchSequence to be extendable
Born out of necessity
Support grouping of steps.
- In practice, only GROUP_TOP_LEVEL is used

title: The ReflectionSequence class (2)

getExecutionOrder() returns array of steps using method names

return new String[] { "stepGDBVersion",
                      "stepSetEnvironmentDirectory",
                      "stepSetBreakpointPending",
                    ...

getExecutionOrder() can be overridden to add/remove steps
Steps are implemented by methods with specific name and tagged with @Execute

title: Extending GDB Initialization Sequence

Have FrameSpyFinalLaunchSequence extend FinalLaunchSequence
Add a new stepSetVerbose() to this initialization sequence
- Reset to DSF9.2_START or DSF9.2_ADVANCED
- Go!

title: Instantiating the new sequence

As for previous steps, we need to instantiate our new sequence

title: Using new initialization Sequence

Have FrameSpyControlService extend the existing ICommandControl service
Override getCompleteInitializationSequence() to choose new launch sequence
- Reset to DSF9.3_ADVANCED
- Go!

title: Final Recap

We've created a new view that used existing services
We've created a new service that the new view can use
We've created a replacement service for our own delegate
We've modified GDB's initialization sequence

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But the button does not belong in view itself, it would be nicer in the toolbar.

If you enable logging and close/reopen the view, what happens?

What happens?

With this knowledge we can fix the Invalid Thread Access. We can use asyncExec in this case. (PLUG10)

title: Exercise Review

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But the button does not belong in view itself, it would be nicer in the toolbar.

If you enable logging and close/reopen the view, what happens?

What happens?

With this knowledge we can fix the Invalid Thread Access. We can use asyncExec in this case. (PLUG10)

title: Exercise Review