display(self, message)

Hook to allow the calling interface to display a message.

This hook gets called as part of preparing a task for execution (that is, a Node to be built). As part of figuring out what Node should be built next, the actually target list may be altered, along with a message describing the alteration. The calling interface can subclass Task and provide a concrete implementation of this method to see those messages.

exc_clear(self)

Clears any recorded exception.

This also changes the "exception_raise" attribute to point to the appropriate do-nothing method.

exc_info(self)

Returns info about a recorded exception.

exception_set(self, exception=None)

Records an exception to be raised at the appropriate time.

This also changes the "exception_raise" attribute to point to the method that will, in fact

execute(self)

Called to execute the task.

This method is called from multiple threads in a parallel build, so only do thread safe stuff here. Do thread unsafe stuff in prepare(), executed() or failed().

executed(self)

Called when the task has been successfully executed and the Taskmaster instance wants to call the Node's callback methods.

This may have been a do-nothing operation (to preserve build order), so we must check the node's state before deciding whether it was "built", in which case we call the appropriate Node method. In any event, we always call "visited()", which will handle any post-visit actions that must take place regardless of whether or not the target was an actual built target or a source Node.

executed_with_callbacks(self)

Called when the task has been successfully executed and the Taskmaster instance wants to call the Node's callback methods.

This may have been a do-nothing operation (to preserve build order), so we must check the node's state before deciding whether it was "built", in which case we call the appropriate Node method. In any event, we always call "visited()", which will handle any post-visit actions that must take place regardless of whether or not the target was an actual built target or a source Node.

executed_without_callbacks(self)

Called when the task has been successfully executed and the Taskmaster instance doesn't want to call the Node's callback methods.

fail_continue(self)

Explicit continue-the-build failure.

This sets failure status on the target nodes and all of their dependent parent nodes.

fail_stop(self)

Explicit stop-the-build failure.

failed(self)

Default action when a task fails: stop the build.

get_target(self)

Fetch the target being built or updated by this task.

make_ready(self)

Marks all targets in a task ready for execution if any target is not current.

This is the default behavior for building only what's necessary.

make_ready_all(self)

Marks all targets in a task ready for execution.

This is used when the interface needs every target Node to be visited--the canonical example being the "scons -c" option.

make_ready_current(self)

Marks all targets in a task ready for execution if any target is not current.

This is the default behavior for building only what's necessary.

postprocess(self)

Post-processes a task after it's been executed.

This examines all the targets just built (or not, we don't care if the build was successful, or even if there was no build because everything was up-to-date) to see if they have any waiting parent Nodes, or Nodes waiting on a common side effect, that can be put back on the candidates list.

prepare(self)

Called just before the task is executed.

This is mainly intended to give the target Nodes a chance to unlink underlying files and make all necessary directories before the Action is actually called to build the targets.