Oovcde Index
Oovcde Multitasking
The Oovcde program uses many types of multitasking. This provides a brief
explanation of the design and implementation, and what design issues are handled.
- How many threads are run
- How to stop and start threads
- Whether to fail requests when busy, or stop and start new request
- How is output status handled
- How to isolate GUI thread
Editor Highlighting
The OovEditor uses a background thread to run CLang in order to perform
syntax highlighting.
Since the compiler cannot be stopped, a check is made at completion to see
if there were any changes since it was started, and CLang is restarted if so.
When the highlight information is updated, the foreground thread applies the
information to the editor view.
When the view is loaded or edited, a highlight request is made using
ThreadedWorkBackgroundQueue
class that indicates that highlighting is needed.
The ThreadedWorkBackgroundQueue provides a single background thread that
starts CLang when the request is made, and updates the highlight information.
The GUI idle processing is used to update the view with the new highlight
information.
At the moment, there is a single thread for each file view.
Builder
The OovBuilder runs CLang to compile analysis information, and to compile
object files. It also runs other build tools such as nm, and ar, to
get symbol names, build libraries, and to link programs. The goal is to
run as many processes at once while not bogging down the system too much.
The output is sent to the calling program using stdout and stderr,
so that the user can see the output status of each of the build tools.
When a project is analyzed or built, many source files must be compiled
using CLang or one of the other build tools. The build tool process name,
source file name, and arguments are queued using the
ThreadedWorkWaitQueue
class. This queue runs many background threads that each wait from
something to be put on the queue. The client thread only puts things on
the queue if the queue is empty. This reduces the amount of memory used
since many files may have to be processed.
Oovcde
The Oovcde program performs many types of background tasks that are
described below.
Building
The Oovcde program runs the OovBuilder on a background thread so that
other tasks can be performed during a build. The std output of the
builder program shows up in a view in the Oovcde program.
The Oovcde program runs the background builder process using the
OovBackgroundPipeProcess class. This class has a background thread
that listens to the stdout and
stderr of the OovBuilder, and calls a listener callback. The Oovcde
program buffers this data and updates the view with the GUI idle
processing. The Oovcde program is able to kill the OovBuilder
child process at any time.
Loading Analysis Files
The Oovcde program takes some time to load the analysis files for
large projects. During this time, a non-modal screen is displayed
which shows progress, and allows cancelling the loading of files.
Requesting a new load while busy will allow the user to continue
the original load, or start the new load.
When the analysis files are loaded, the
ThreadedWorkBackgroundQueue
class is used that indicates that the analysis must be performed.
A listener is used so that the background thread can update progress
status. The Oovcde program updates the status using the GUI idle
processing and allows the user to abort placement.
An analysis status flag is also updated by the worker
thread. This flag is used to fail client function requests until
the analysis has ended. The GUI part of the Oovcde program detects
the failure, and displays a message to the user to request whether
to stop and start the new job, or let the old job continue.
Updating the Class Graph
The Oovcde program takes time to update class graphs since it
uses a genetic algorithm to optimize class placement in diagrams.
When the graph must be updated, the
ThreadedWorkBackgroundQueue
class is used that indicates that the placement must be performed.
When the placement is complete, it requests the GUI to redraw.
Apparently this GUI provided queue function is thread safe.
A listener is used so that the background thread can update progress
status. The Oovcde program updates the status using the GUI idle
processing and allows the user to abort placement.
When the GUI requests the graph to update, and it is already busy,
it simply stops the current placement and starts the next placement
without notifying the user.