An Overview of Tools Available in CS 501

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An Overview of Tools Available in CS 501

• Ken Hopkinson
• hopkik_at_cs.cornell.edu

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Talk Overview

• Rational Rose for Design
• Source Management Tools
• A Selection of Available Development Environments
• Debugging Techniques

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Using Rational Rose for Project Design
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Start Rational Rose
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A Typical Design
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Another Sample Design Case
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Remember Your Specifications
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Specification Fields
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General Specification Fields
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Source Code Management

• Also known as Configuration Management
• Source Code Managers are tools that
• Archive your development files
• Serve as a single point of entry/exit when adding
  or updating development files

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Why You Want A Source Control System

• Supports concurrent development
• Manage diverging source code bases
• Records file/release versions
• Easy access to all previous revisions
• Can record why a revision was made
• Optimal disk space usage
• Youll end up doing something equivalent anyway
  so it may as well be automated

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Source Code Management Tools Are Not

• A substitute for project management
• A replacement for developer communication

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How They Work

• Central database of source code, documentation,
  build tools
• Each file stored only once - all other versions
  are diffs of that one copy
• To Make a Change
• Check out the latest version of a file
• Make the changes
• Update the database

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What should be in the database

• Source Code
• Documentation
• Build Tools
• Often need old versions of the tools to build old
  versions of the software
• Ensures software is rebuilt exactly as the
  customer received it
• Test Suites
• Anything else you might want later

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Version Control

• Companies ship several products from the same
  source base (ie Win NT and Windows 2000 versions
  of MS Office)
• When tracking down bugs you want to examine the
  code as it was when the product shipped

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Code Sharing

• Multiple people can work on the same source base
  without colliding
• (1) Locks individual files so only one person at
  a time can modify it OR
• (2) Allows multiple people to modify a source
  file and the system will automatically merge the
  changes (usually)

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Locking

• Only one person can work on a file at once
• Works fairly well if developers work on different
  areas of the project and dont conflict often
• Problem 1 People forget to unlock files when
  they are done
• Problem 2 People work around locking by editing
  a private copy and checking in when the file is
  finally unlocked - easy to goof and lose changes

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Merging

• Several people can work on a file at once
• Before committing changes, each user merges their
  copy with the latest copy in the database
• This is normally done automatically by the system
  and usually works, but you should not blindly
  accept the result of the merge

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Labelling

• Label all the files in the source base that make
  up a product at each milestone
• Just before and just after a major change (eg.
  changing several interfaces)
• When a new version ships

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Version Trees

• Each file in the database has a version tree
• Can branch off the version tree to allow separate
  development paths
• Typically a main path (trunk) for the next major
  version and branches off of shipped versions for
  maintenance

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Branching

• When a new version ships, typically create a
  branch in the version tree for maintenance
• Double update fix a defect in the latest version
  and then merge the changes (often by hand) into
  the maintenance version
• Also create personal versions so you can make a
  change against a stable source base and then
  merge in the latest version later

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Examples

• RCS
• Solaris man rcsintro
• CVS
• Solaris man cvs
• www.cyclic.com/cvs/info.html
• Visual SourceSafe
• msdn.microsoft.com/SSAFE
• ClearCase
• www.rational.com
• SourceForge
• www.sourceforge.net

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RCS

• File management only
• Transaction model
• check out and lock
• edit
• check in and unlock
• Little support for binaries

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CVS

• Built on top of RCS
• Therefore little support for binaries
• Database can be remote
• No locking merge before commit
• Fast
• Integrates with emacs

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SourceSafe

• Microsofts entry into the field
• Project-based
• Checkout-edit-checkin model
• Built-in web site creation tools
• Integrates with MSDEV

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Clearcase

• Clearcase is configuration management on steroids
• You create a view of the database with a config
  spec, which describes how to select files from
  the database.
• When you set a view, Clearcase creates a virtual
  filesystem containing only those versions of the
  files selected by the config spec

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Clearcase Features

• Distributed System
• Several groups at different locations can work on
  the same database
• Can install triggers
• Example e-mail the author of a file when some
  one makes a change to it
• Uses merging model like CVS, but can also lock
  files

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More Clearcase Features

• Integrates with MSDEV
• Build Management
• Knows to rebuild out-of-date files even if your
  makefile doesnt
• Slow and a bit buggy

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SourceForge

• On-line Version Control System
• Projects are available for public discovery and
  development
• A very good environment for open source projects

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Helpful Rules for Version Control Bliss

• Archived Files Should Always Compile
• Code Review Files Before Check-in
• Compile and run latest archived files as a
  set before Check-in
• No Cheating (even simple bug fixes need to
  undergo this process)

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Development Tools Available at Cornell at No
Charge to You
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MSDNAA

• Windows XP
• Visual Studio .Net
• Windows CE Development Tools
• Microsoft SQL Server
• Visual SourceSafe

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Freely Available Software

• GNU
• Free Software Foundation
• Other Public Software Freely Distributed

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Useful Public Software

• Apache Web Server
• g/gdb
• Perl
• Python
• CVS

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Software Installed in Public Windows/Unix Labs

• Microsoft Office including MS Access
• Purify
• CVS Server
• Unix Shell Access

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Key Points to Remember

• Use the most appropriate tools for the job
• Check available Cornell software before buying
  anything
• Ignore licensing agreements at your peril
• No extra credit is given for a one week project
  that does the same work as a one-line library
  call.

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A Closer Look at Two Cool Development Tools

• Purify
• Microsoft Visual Debugger

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Purify

• Purify is a tool for locating runtime errors in a
  C/C program
• Purify can find
• Array bounds errors
• Accesses through dangling pointers
• Uninitialized memory reads
• Memory allocation errors
• Memory leaks
• Purify is available on Windows and UNIX systems
  and is a product of Rational Software
  www.rational.com

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How Purify Works

• Purify instruments a program by adding protection
  instructions around every load and store
  operation
• When program is executed a viewer will be created
  to display errors as they happen
• Purify is flexible and can be run standalone with
  any executable (written in C) or within a
  debugging environment like Visual Studio
• Purify is customizable and can be set to ignore
  certain types of errors

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How to Use Purify

• add purify command to link command
• program (OBJS)
• purify -option ... (CC) (CFLAGS)
  -o\ program (OBJS) (LIBS)
• OR run purify in Visual Studio
• OR load file in purify executable

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Visual Debugger

• Graphically Oriented
• Run from Visual Studio
• Can debug a failed process by selecting the Yes
  button at Debug Application dialog after a
  memory or other failure occurs
• Can attach to a running process by choosing the
  Tools-gtStart Debug-gtAttach to Process menu option

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The Visual Debugger
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Breakpoints

• Can stop execution at any line and in any
  function. (Location)
• Can set conditions on breakpoints if you are only
  interested in specific passes through a piece of
  code (Location-gtCondition)
• Conditional breakpoints detached from any one
  line in the program are also possible, but make
  program execution very slow (Data).

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Breakpoint Window
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Conditional Window
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Conditional Data Breakpoint
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Examining Program State

• Print and/or Change variable state.
• Walk up/down the stack trace.
• View disassembled code.

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Quick Print/Change Variables
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Common Pointer Problems

• Pointer to bogus memory
• Corrupt data structure segments
• Data sharing errors
• Accessing data elements of the wrong type
• Attempting to use memory areas after freeing them

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Conclusion

• Rational Rose is an Excellent Design Tool
• Version Control Software is Very Helpful
• Many Good Project Tools Available at Cornell
• Using Development Tools Well Can Make a Big
  Difference in Your Projects Success