Package SCons :: Module Taskmaster

Module Taskmaster

This module contains the primary interface(s) between a wrapping user interface and the SCons build engine. There are two key classes here:

Taskmaster

This is the main engine for walking the dependency graph and calling things to decide what does or doesn't need to be built.

Task

This is the base class for allowing a wrapping interface to decide what does or doesn't actually need to be done. The intention is for a wrapping interface to subclass this as appropriate for different types of behavior it may need.

The canonical example is the SCons native Python interface, which has Task subclasses that handle its specific behavior, like printing "'foo' is up to date" when a top-level target doesn't need to be built, and handling the -c option by removing targets as its "build" action. There is also a separate subclass for suppressing this output when the -q option is used.

The Taskmaster instantiates a Task object for each (set of) target(s) that it decides need to be evaluated and/or built.

Classes

[hide private]

Stats
A simple class for holding statistics about the disposition of a Node by the Taskmaster. If we're collecting statistics, each Node processed by the Taskmaster gets one of these attached, in which case the Taskmaster records its decision each time it processes the Node. (Ideally, that's just once per Node.)

Task
Default SCons build engine task.

AlwaysTask

OutOfDateTask

Taskmaster
The Taskmaster for walking the dependency DAG.

Functions

[hide private]

dump_stats()

source code

find_cycle(stack, visited)

source code

Variables

[hide private]

__doc__ = ...

__revision__ = 'src/engine/SCons/Taskmaster.py 3a41ed6b288cee8...

StateString = {0: 'no_state', 1: 'pending', 2: 'executing', 3:...

NODE_NO_STATE = 0

NODE_PENDING = 1

NODE_EXECUTING = 2

NODE_UP_TO_DATE = 3

NODE_EXECUTED = 4

NODE_FAILED = 5

print_prepare = 0

CollectStats = None
hash(x)

StatsNodes = []

fmt = '%(considered)3d %(already_handled)3d %(problem)3d %(chi...

__package__ = 'SCons'

Variables Details

[hide private]

doc

Value:

"""
    Generic Taskmaster module for the SCons build engine.
    =====================================================
    
    This module contains the primary interface(s) between a wrapping u
ser
    interface and the SCons build engine.  There are two key classes h
ere:
...

revision

Value:

'src/engine/SCons/Taskmaster.py 3a41ed6b288cee8d085373ad7fa02894e19038
64 2019-01-23 17:30:35 bdeegan'

StateString

Value:

{0: 'no_state',
 1: 'pending',
 2: 'executing',
 3: 'up_to_date',
 4: 'executed',
 5: 'failed'}

fmt

Value:

'%(considered)3d %(already_handled)3d %(problem)3d %(child_failed)3d %
(not_built)3d %(side_effects)3d %(build)3d '