e74be337b0
- remove SourceCode (depricated in >= 4.x)
- remove 'FAST' option as SetCacheMode('force') broken in >= 3.0.5
1068 lines
40 KiB
Python
1068 lines
40 KiB
Python
#
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# __COPYRIGHT__
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be included
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# in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
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# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
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# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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import sys
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__doc__ = """
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Generic Taskmaster module for the SCons build engine.
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=====================================================
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This module contains the primary interface(s) between a wrapping user
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interface and the SCons build engine. There are two key classes here:
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Taskmaster
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----------
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This is the main engine for walking the dependency graph and
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calling things to decide what does or doesn't need to be built.
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Task
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----
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This is the base class for allowing a wrapping interface to
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decide what does or doesn't actually need to be done. The
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intention is for a wrapping interface to subclass this as
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appropriate for different types of behavior it may need.
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The canonical example is the SCons native Python interface,
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which has Task subclasses that handle its specific behavior,
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like printing "'foo' is up to date" when a top-level target
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doesn't need to be built, and handling the -c option by removing
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targets as its "build" action. There is also a separate subclass
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for suppressing this output when the -q option is used.
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The Taskmaster instantiates a Task object for each (set of)
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target(s) that it decides need to be evaluated and/or built.
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"""
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__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
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import operator
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import sys
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import traceback
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from abc import ABC, abstractmethod
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from itertools import chain
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import SCons.Errors
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import SCons.Node
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import SCons.Warnings
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StateString = SCons.Node.StateString
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NODE_NO_STATE = SCons.Node.no_state
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NODE_PENDING = SCons.Node.pending
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NODE_EXECUTING = SCons.Node.executing
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NODE_UP_TO_DATE = SCons.Node.up_to_date
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NODE_EXECUTED = SCons.Node.executed
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NODE_FAILED = SCons.Node.failed
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print_prepare = 0 # set by option --debug=prepare
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# A subsystem for recording stats about how different Nodes are handled by
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# the main Taskmaster loop. There's no external control here (no need for
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# a --debug= option); enable it by changing the value of CollectStats.
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CollectStats = None
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class Stats:
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"""
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A simple class for holding statistics about the disposition of a
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Node by the Taskmaster. If we're collecting statistics, each Node
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processed by the Taskmaster gets one of these attached, in which case
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the Taskmaster records its decision each time it processes the Node.
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(Ideally, that's just once per Node.)
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"""
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def __init__(self):
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"""
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Instantiates a Taskmaster.Stats object, initializing all
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appropriate counters to zero.
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"""
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self.considered = 0
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self.already_handled = 0
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self.problem = 0
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self.child_failed = 0
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self.not_built = 0
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self.side_effects = 0
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self.build = 0
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StatsNodes = []
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fmt = "%(considered)3d "\
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"%(already_handled)3d " \
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"%(problem)3d " \
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"%(child_failed)3d " \
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"%(not_built)3d " \
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"%(side_effects)3d " \
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"%(build)3d "
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def dump_stats():
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for n in sorted(StatsNodes, key=lambda a: str(a)):
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print((fmt % n.attributes.stats.__dict__) + str(n))
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class Task(ABC):
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""" SCons build engine abstract task class.
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This controls the interaction of the actual building of node
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and the rest of the engine.
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This is expected to handle all of the normally-customizable
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aspects of controlling a build, so any given application
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*should* be able to do what it wants by sub-classing this
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class and overriding methods as appropriate. If an application
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needs to customize something by sub-classing Taskmaster (or
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some other build engine class), we should first try to migrate
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that functionality into this class.
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Note that it's generally a good idea for sub-classes to call
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these methods explicitly to update state, etc., rather than
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roll their own interaction with Taskmaster from scratch.
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"""
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def __init__(self, tm, targets, top, node):
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self.tm = tm
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self.targets = targets
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self.top = top
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self.node = node
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self.exc_clear()
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def trace_message(self, method, node, description='node'):
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fmt = '%-20s %s %s\n'
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return fmt % (method + ':', description, self.tm.trace_node(node))
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def display(self, message):
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"""
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Hook to allow the calling interface to display a message.
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This hook gets called as part of preparing a task for execution
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(that is, a Node to be built). As part of figuring out what Node
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should be built next, the actual target list may be altered,
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along with a message describing the alteration. The calling
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interface can subclass Task and provide a concrete implementation
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of this method to see those messages.
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"""
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pass
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def prepare(self):
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"""
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Called just before the task is executed.
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This is mainly intended to give the target Nodes a chance to
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unlink underlying files and make all necessary directories before
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the Action is actually called to build the targets.
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"""
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global print_prepare
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T = self.tm.trace
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if T: T.write(self.trace_message('Task.prepare()', self.node))
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# Now that it's the appropriate time, give the TaskMaster a
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# chance to raise any exceptions it encountered while preparing
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# this task.
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self.exception_raise()
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if self.tm.message:
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self.display(self.tm.message)
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self.tm.message = None
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# Let the targets take care of any necessary preparations.
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# This includes verifying that all of the necessary sources
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# and dependencies exist, removing the target file(s), etc.
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#
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# As of April 2008, the get_executor().prepare() method makes
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# sure that all of the aggregate sources necessary to build this
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# Task's target(s) exist in one up-front check. The individual
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# target t.prepare() methods check that each target's explicit
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# or implicit dependencies exists, and also initialize the
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# .sconsign info.
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executor = self.targets[0].get_executor()
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if executor is None:
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return
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executor.prepare()
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for t in executor.get_action_targets():
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if print_prepare:
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print("Preparing target %s..."%t)
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for s in t.side_effects:
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print("...with side-effect %s..."%s)
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t.prepare()
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for s in t.side_effects:
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if print_prepare:
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print("...Preparing side-effect %s..."%s)
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s.prepare()
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def get_target(self):
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"""Fetch the target being built or updated by this task.
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"""
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return self.node
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@abstractmethod
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def needs_execute(self):
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return
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def execute(self):
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"""
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Called to execute the task.
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This method is called from multiple threads in a parallel build,
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so only do thread safe stuff here. Do thread unsafe stuff in
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prepare(), executed() or failed().
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"""
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T = self.tm.trace
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if T: T.write(self.trace_message('Task.execute()', self.node))
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try:
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cached_targets = []
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for t in self.targets:
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if not t.retrieve_from_cache():
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break
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cached_targets.append(t)
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if len(cached_targets) < len(self.targets):
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# Remove targets before building. It's possible that we
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# partially retrieved targets from the cache, leaving
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# them in read-only mode. That might cause the command
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# to fail.
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#
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for t in cached_targets:
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try:
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t.fs.unlink(t.get_internal_path())
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except (IOError, OSError):
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pass
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self.targets[0].build()
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else:
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for t in cached_targets:
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t.cached = 1
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except SystemExit:
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exc_value = sys.exc_info()[1]
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raise SCons.Errors.ExplicitExit(self.targets[0], exc_value.code)
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except SCons.Errors.UserError:
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raise
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except SCons.Errors.BuildError:
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raise
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except Exception as e:
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buildError = SCons.Errors.convert_to_BuildError(e)
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buildError.node = self.targets[0]
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buildError.exc_info = sys.exc_info()
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raise buildError
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def executed_without_callbacks(self):
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"""
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Called when the task has been successfully executed
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and the Taskmaster instance doesn't want to call
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the Node's callback methods.
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"""
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T = self.tm.trace
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if T: T.write(self.trace_message('Task.executed_without_callbacks()',
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self.node))
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for t in self.targets:
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if t.get_state() == NODE_EXECUTING:
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for side_effect in t.side_effects:
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side_effect.set_state(NODE_NO_STATE)
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t.set_state(NODE_EXECUTED)
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def executed_with_callbacks(self):
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"""
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Called when the task has been successfully executed and
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the Taskmaster instance wants to call the Node's callback
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methods.
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This may have been a do-nothing operation (to preserve build
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order), so we must check the node's state before deciding whether
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it was "built", in which case we call the appropriate Node method.
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In any event, we always call "visited()", which will handle any
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post-visit actions that must take place regardless of whether
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or not the target was an actual built target or a source Node.
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"""
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global print_prepare
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T = self.tm.trace
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if T: T.write(self.trace_message('Task.executed_with_callbacks()',
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self.node))
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for t in self.targets:
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if t.get_state() == NODE_EXECUTING:
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for side_effect in t.side_effects:
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side_effect.set_state(NODE_NO_STATE)
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t.set_state(NODE_EXECUTED)
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if not t.cached:
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t.push_to_cache()
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t.built()
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t.visited()
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if (not print_prepare and
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(not hasattr(self, 'options') or not self.options.debug_includes)):
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t.release_target_info()
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else:
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t.visited()
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executed = executed_with_callbacks
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def failed(self):
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"""
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Default action when a task fails: stop the build.
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Note: Although this function is normally invoked on nodes in
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the executing state, it might also be invoked on up-to-date
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nodes when using Configure().
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"""
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self.fail_stop()
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def fail_stop(self):
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"""
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Explicit stop-the-build failure.
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This sets failure status on the target nodes and all of
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their dependent parent nodes.
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Note: Although this function is normally invoked on nodes in
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the executing state, it might also be invoked on up-to-date
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nodes when using Configure().
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"""
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T = self.tm.trace
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if T: T.write(self.trace_message('Task.failed_stop()', self.node))
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# Invoke will_not_build() to clean-up the pending children
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# list.
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self.tm.will_not_build(self.targets, lambda n: n.set_state(NODE_FAILED))
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# Tell the taskmaster to not start any new tasks
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self.tm.stop()
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# We're stopping because of a build failure, but give the
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# calling Task class a chance to postprocess() the top-level
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# target under which the build failure occurred.
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self.targets = [self.tm.current_top]
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self.top = 1
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def fail_continue(self):
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"""
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Explicit continue-the-build failure.
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This sets failure status on the target nodes and all of
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their dependent parent nodes.
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Note: Although this function is normally invoked on nodes in
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the executing state, it might also be invoked on up-to-date
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nodes when using Configure().
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"""
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T = self.tm.trace
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if T: T.write(self.trace_message('Task.failed_continue()', self.node))
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self.tm.will_not_build(self.targets, lambda n: n.set_state(NODE_FAILED))
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def make_ready_all(self):
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"""
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Marks all targets in a task ready for execution.
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This is used when the interface needs every target Node to be
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visited--the canonical example being the "scons -c" option.
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"""
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T = self.tm.trace
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if T: T.write(self.trace_message('Task.make_ready_all()', self.node))
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self.out_of_date = self.targets[:]
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for t in self.targets:
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t.disambiguate().set_state(NODE_EXECUTING)
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for s in t.side_effects:
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# add disambiguate here to mirror the call on targets above
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s.disambiguate().set_state(NODE_EXECUTING)
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def make_ready_current(self):
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"""
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Marks all targets in a task ready for execution if any target
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is not current.
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This is the default behavior for building only what's necessary.
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"""
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global print_prepare
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T = self.tm.trace
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if T: T.write(self.trace_message('Task.make_ready_current()',
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self.node))
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self.out_of_date = []
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needs_executing = False
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for t in self.targets:
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try:
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t.disambiguate().make_ready()
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is_up_to_date = not t.has_builder() or \
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(not t.always_build and t.is_up_to_date())
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except EnvironmentError as e:
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raise SCons.Errors.BuildError(node=t, errstr=e.strerror, filename=e.filename)
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if not is_up_to_date:
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self.out_of_date.append(t)
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needs_executing = True
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if needs_executing:
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for t in self.targets:
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t.set_state(NODE_EXECUTING)
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for s in t.side_effects:
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# add disambiguate here to mirror the call on targets in first loop above
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s.disambiguate().set_state(NODE_EXECUTING)
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else:
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for t in self.targets:
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# We must invoke visited() to ensure that the node
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# information has been computed before allowing the
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# parent nodes to execute. (That could occur in a
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# parallel build...)
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t.visited()
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t.set_state(NODE_UP_TO_DATE)
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if (not print_prepare and
|
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(not hasattr(self, 'options') or not self.options.debug_includes)):
|
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t.release_target_info()
|
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|
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make_ready = make_ready_current
|
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|
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def postprocess(self):
|
|
"""
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|
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
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|
because everything was up-to-date) to see if they have any
|
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waiting parent Nodes, or Nodes waiting on a common side effect,
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|
that can be put back on the candidates list.
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"""
|
|
T = self.tm.trace
|
|
if T: T.write(self.trace_message('Task.postprocess()', self.node))
|
|
|
|
# We may have built multiple targets, some of which may have
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# common parents waiting for this build. Count up how many
|
|
# targets each parent was waiting for so we can subtract the
|
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# values later, and so we *don't* put waiting side-effect Nodes
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# back on the candidates list if the Node is also a waiting
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# parent.
|
|
|
|
targets = set(self.targets)
|
|
|
|
pending_children = self.tm.pending_children
|
|
parents = {}
|
|
for t in targets:
|
|
# A node can only be in the pending_children set if it has
|
|
# some waiting_parents.
|
|
if t.waiting_parents:
|
|
if T: T.write(self.trace_message('Task.postprocess()',
|
|
t,
|
|
'removing'))
|
|
pending_children.discard(t)
|
|
for p in t.waiting_parents:
|
|
parents[p] = parents.get(p, 0) + 1
|
|
t.waiting_parents = set()
|
|
|
|
for t in targets:
|
|
if t.side_effects is not None:
|
|
for s in t.side_effects:
|
|
if s.get_state() == NODE_EXECUTING:
|
|
s.set_state(NODE_NO_STATE)
|
|
|
|
# The side-effects may have been transferred to
|
|
# NODE_NO_STATE by executed_with{,out}_callbacks, but was
|
|
# not taken out of the waiting parents/pending children
|
|
# data structures. Check for that now.
|
|
if s.get_state() == NODE_NO_STATE and s.waiting_parents:
|
|
pending_children.discard(s)
|
|
for p in s.waiting_parents:
|
|
parents[p] = parents.get(p, 0) + 1
|
|
s.waiting_parents = set()
|
|
for p in s.waiting_s_e:
|
|
if p.ref_count == 0:
|
|
self.tm.candidates.append(p)
|
|
|
|
for p, subtract in parents.items():
|
|
p.ref_count = p.ref_count - subtract
|
|
if T: T.write(self.trace_message('Task.postprocess()',
|
|
p,
|
|
'adjusted parent ref count'))
|
|
if p.ref_count == 0:
|
|
self.tm.candidates.append(p)
|
|
|
|
for t in targets:
|
|
t.postprocess()
|
|
|
|
# Exception handling subsystem.
|
|
#
|
|
# Exceptions that occur while walking the DAG or examining Nodes
|
|
# must be raised, but must be raised at an appropriate time and in
|
|
# a controlled manner so we can, if necessary, recover gracefully,
|
|
# possibly write out signature information for Nodes we've updated,
|
|
# etc. This is done by having the Taskmaster tell us about the
|
|
# exception, and letting
|
|
|
|
def exc_info(self):
|
|
"""
|
|
Returns info about a recorded exception.
|
|
"""
|
|
return self.exception
|
|
|
|
def exc_clear(self):
|
|
"""
|
|
Clears any recorded exception.
|
|
|
|
This also changes the "exception_raise" attribute to point
|
|
to the appropriate do-nothing method.
|
|
"""
|
|
self.exception = (None, None, None)
|
|
self.exception_raise = self._no_exception_to_raise
|
|
|
|
def 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
|
|
"""
|
|
if not exception:
|
|
exception = sys.exc_info()
|
|
self.exception = exception
|
|
self.exception_raise = self._exception_raise
|
|
|
|
def _no_exception_to_raise(self):
|
|
pass
|
|
|
|
def _exception_raise(self):
|
|
"""
|
|
Raises a pending exception that was recorded while getting a
|
|
Task ready for execution.
|
|
"""
|
|
exc = self.exc_info()[:]
|
|
try:
|
|
exc_type, exc_value, exc_traceback = exc
|
|
except ValueError:
|
|
exc_type, exc_value = exc # pylint: disable=unbalanced-tuple-unpacking
|
|
exc_traceback = None
|
|
|
|
# raise exc_type(exc_value).with_traceback(exc_traceback)
|
|
if isinstance(exc_value, Exception): #hasattr(exc_value, 'with_traceback'):
|
|
# If exc_value is an exception, then just reraise
|
|
raise exc_value.with_traceback(exc_traceback)
|
|
else:
|
|
# else we'll create an exception using the value and raise that
|
|
raise exc_type(exc_value).with_traceback(exc_traceback)
|
|
|
|
|
|
# raise e.__class__, e.__class__(e), sys.exc_info()[2]
|
|
# exec("raise exc_type(exc_value).with_traceback(exc_traceback)")
|
|
|
|
|
|
|
|
class AlwaysTask(Task):
|
|
def needs_execute(self):
|
|
"""
|
|
Always returns True (indicating this Task should always
|
|
be executed).
|
|
|
|
Subclasses that need this behavior (as opposed to the default
|
|
of only executing Nodes that are out of date w.r.t. their
|
|
dependencies) can use this as follows:
|
|
|
|
class MyTaskSubclass(SCons.Taskmaster.Task):
|
|
needs_execute = SCons.Taskmaster.AlwaysTask.needs_execute
|
|
"""
|
|
return True
|
|
|
|
class OutOfDateTask(Task):
|
|
def needs_execute(self):
|
|
"""
|
|
Returns True (indicating this Task should be executed) if this
|
|
Task's target state indicates it needs executing, which has
|
|
already been determined by an earlier up-to-date check.
|
|
"""
|
|
return self.targets[0].get_state() == SCons.Node.executing
|
|
|
|
|
|
def find_cycle(stack, visited):
|
|
if stack[-1] in visited:
|
|
return None
|
|
visited.add(stack[-1])
|
|
for n in stack[-1].waiting_parents:
|
|
stack.append(n)
|
|
if stack[0] == stack[-1]:
|
|
return stack
|
|
if find_cycle(stack, visited):
|
|
return stack
|
|
stack.pop()
|
|
return None
|
|
|
|
|
|
class Taskmaster:
|
|
"""
|
|
The Taskmaster for walking the dependency DAG.
|
|
"""
|
|
|
|
def __init__(self, targets=[], tasker=None, order=None, trace=None):
|
|
self.original_top = targets
|
|
self.top_targets_left = targets[:]
|
|
self.top_targets_left.reverse()
|
|
self.candidates = []
|
|
if tasker is None:
|
|
tasker = OutOfDateTask
|
|
self.tasker = tasker
|
|
if not order:
|
|
order = lambda l: l
|
|
self.order = order
|
|
self.message = None
|
|
self.trace = trace
|
|
self.next_candidate = self.find_next_candidate
|
|
self.pending_children = set()
|
|
|
|
def find_next_candidate(self):
|
|
"""
|
|
Returns the next candidate Node for (potential) evaluation.
|
|
|
|
The candidate list (really a stack) initially consists of all of
|
|
the top-level (command line) targets provided when the Taskmaster
|
|
was initialized. While we walk the DAG, visiting Nodes, all the
|
|
children that haven't finished processing get pushed on to the
|
|
candidate list. Each child can then be popped and examined in
|
|
turn for whether *their* children are all up-to-date, in which
|
|
case a Task will be created for their actual evaluation and
|
|
potential building.
|
|
|
|
Here is where we also allow candidate Nodes to alter the list of
|
|
Nodes that should be examined. This is used, for example, when
|
|
invoking SCons in a source directory. A source directory Node can
|
|
return its corresponding build directory Node, essentially saying,
|
|
"Hey, you really need to build this thing over here instead."
|
|
"""
|
|
try:
|
|
return self.candidates.pop()
|
|
except IndexError:
|
|
pass
|
|
try:
|
|
node = self.top_targets_left.pop()
|
|
except IndexError:
|
|
return None
|
|
self.current_top = node
|
|
alt, message = node.alter_targets()
|
|
if alt:
|
|
self.message = message
|
|
self.candidates.append(node)
|
|
self.candidates.extend(self.order(alt))
|
|
node = self.candidates.pop()
|
|
return node
|
|
|
|
def no_next_candidate(self):
|
|
"""
|
|
Stops Taskmaster processing by not returning a next candidate.
|
|
|
|
Note that we have to clean-up the Taskmaster candidate list
|
|
because the cycle detection depends on the fact all nodes have
|
|
been processed somehow.
|
|
"""
|
|
while self.candidates:
|
|
candidates = self.candidates
|
|
self.candidates = []
|
|
self.will_not_build(candidates)
|
|
return None
|
|
|
|
def _validate_pending_children(self):
|
|
"""
|
|
Validate the content of the pending_children set. Assert if an
|
|
internal error is found.
|
|
|
|
This function is used strictly for debugging the taskmaster by
|
|
checking that no invariants are violated. It is not used in
|
|
normal operation.
|
|
|
|
The pending_children set is used to detect cycles in the
|
|
dependency graph. We call a "pending child" a child that is
|
|
found in the "pending" state when checking the dependencies of
|
|
its parent node.
|
|
|
|
A pending child can occur when the Taskmaster completes a loop
|
|
through a cycle. For example, let's imagine a graph made of
|
|
three nodes (A, B and C) making a cycle. The evaluation starts
|
|
at node A. The Taskmaster first considers whether node A's
|
|
child B is up-to-date. Then, recursively, node B needs to
|
|
check whether node C is up-to-date. This leaves us with a
|
|
dependency graph looking like::
|
|
|
|
Next candidate \
|
|
\
|
|
Node A (Pending) --> Node B(Pending) --> Node C (NoState)
|
|
^ |
|
|
| |
|
|
+-------------------------------------+
|
|
|
|
Now, when the Taskmaster examines the Node C's child Node A,
|
|
it finds that Node A is in the "pending" state. Therefore,
|
|
Node A is a pending child of node C.
|
|
|
|
Pending children indicate that the Taskmaster has potentially
|
|
loop back through a cycle. We say potentially because it could
|
|
also occur when a DAG is evaluated in parallel. For example,
|
|
consider the following graph::
|
|
|
|
Node A (Pending) --> Node B(Pending) --> Node C (Pending) --> ...
|
|
| ^
|
|
| |
|
|
+----------> Node D (NoState) --------+
|
|
/
|
|
Next candidate /
|
|
|
|
The Taskmaster first evaluates the nodes A, B, and C and
|
|
starts building some children of node C. Assuming, that the
|
|
maximum parallel level has not been reached, the Taskmaster
|
|
will examine Node D. It will find that Node C is a pending
|
|
child of Node D.
|
|
|
|
In summary, evaluating a graph with a cycle will always
|
|
involve a pending child at one point. A pending child might
|
|
indicate either a cycle or a diamond-shaped DAG. Only a
|
|
fraction of the nodes ends-up being a "pending child" of
|
|
another node. This keeps the pending_children set small in
|
|
practice.
|
|
|
|
We can differentiate between the two cases if we wait until
|
|
the end of the build. At this point, all the pending children
|
|
nodes due to a diamond-shaped DAG will have been properly
|
|
built (or will have failed to build). But, the pending
|
|
children involved in a cycle will still be in the pending
|
|
state.
|
|
|
|
The taskmaster removes nodes from the pending_children set as
|
|
soon as a pending_children node moves out of the pending
|
|
state. This also helps to keep the pending_children set small.
|
|
"""
|
|
|
|
for n in self.pending_children:
|
|
assert n.state in (NODE_PENDING, NODE_EXECUTING), \
|
|
(str(n), StateString[n.state])
|
|
assert len(n.waiting_parents) != 0, (str(n), len(n.waiting_parents))
|
|
for p in n.waiting_parents:
|
|
assert p.ref_count > 0, (str(n), str(p), p.ref_count)
|
|
|
|
|
|
def trace_message(self, message):
|
|
return 'Taskmaster: %s\n' % message
|
|
|
|
def trace_node(self, node):
|
|
return '<%-10s %-3s %s>' % (StateString[node.get_state()],
|
|
node.ref_count,
|
|
repr(str(node)))
|
|
|
|
def _find_next_ready_node(self):
|
|
"""
|
|
Finds the next node that is ready to be built.
|
|
|
|
This is *the* main guts of the DAG walk. We loop through the
|
|
list of candidates, looking for something that has no un-built
|
|
children (i.e., that is a leaf Node or has dependencies that are
|
|
all leaf Nodes or up-to-date). Candidate Nodes are re-scanned
|
|
(both the target Node itself and its sources, which are always
|
|
scanned in the context of a given target) to discover implicit
|
|
dependencies. A Node that must wait for some children to be
|
|
built will be put back on the candidates list after the children
|
|
have finished building. A Node that has been put back on the
|
|
candidates list in this way may have itself (or its sources)
|
|
re-scanned, in order to handle generated header files (e.g.) and
|
|
the implicit dependencies therein.
|
|
|
|
Note that this method does not do any signature calculation or
|
|
up-to-date check itself. All of that is handled by the Task
|
|
class. This is purely concerned with the dependency graph walk.
|
|
"""
|
|
|
|
self.ready_exc = None
|
|
|
|
T = self.trace
|
|
if T: T.write('\n' + self.trace_message('Looking for a node to evaluate'))
|
|
|
|
while True:
|
|
node = self.next_candidate()
|
|
if node is None:
|
|
if T: T.write(self.trace_message('No candidate anymore.') + '\n')
|
|
return None
|
|
|
|
node = node.disambiguate()
|
|
state = node.get_state()
|
|
|
|
# For debugging only:
|
|
#
|
|
# try:
|
|
# self._validate_pending_children()
|
|
# except:
|
|
# self.ready_exc = sys.exc_info()
|
|
# return node
|
|
|
|
if CollectStats:
|
|
if not hasattr(node.attributes, 'stats'):
|
|
node.attributes.stats = Stats()
|
|
StatsNodes.append(node)
|
|
S = node.attributes.stats
|
|
S.considered = S.considered + 1
|
|
else:
|
|
S = None
|
|
|
|
if T: T.write(self.trace_message(' Considering node %s and its children:' % self.trace_node(node)))
|
|
|
|
if state == NODE_NO_STATE:
|
|
# Mark this node as being on the execution stack:
|
|
node.set_state(NODE_PENDING)
|
|
elif state > NODE_PENDING:
|
|
# Skip this node if it has already been evaluated:
|
|
if S: S.already_handled = S.already_handled + 1
|
|
if T: T.write(self.trace_message(' already handled (executed)'))
|
|
continue
|
|
|
|
executor = node.get_executor()
|
|
|
|
try:
|
|
children = executor.get_all_children()
|
|
except SystemExit:
|
|
exc_value = sys.exc_info()[1]
|
|
e = SCons.Errors.ExplicitExit(node, exc_value.code)
|
|
self.ready_exc = (SCons.Errors.ExplicitExit, e)
|
|
if T: T.write(self.trace_message(' SystemExit'))
|
|
return node
|
|
except Exception as e:
|
|
# We had a problem just trying to figure out the
|
|
# children (like a child couldn't be linked in to a
|
|
# VariantDir, or a Scanner threw something). Arrange to
|
|
# raise the exception when the Task is "executed."
|
|
self.ready_exc = sys.exc_info()
|
|
if S: S.problem = S.problem + 1
|
|
if T: T.write(self.trace_message(' exception %s while scanning children.\n' % e))
|
|
return node
|
|
|
|
children_not_visited = []
|
|
children_pending = set()
|
|
children_not_ready = []
|
|
children_failed = False
|
|
|
|
for child in chain(executor.get_all_prerequisites(), children):
|
|
childstate = child.get_state()
|
|
|
|
if T: T.write(self.trace_message(' ' + self.trace_node(child)))
|
|
|
|
if childstate == NODE_NO_STATE:
|
|
children_not_visited.append(child)
|
|
elif childstate == NODE_PENDING:
|
|
children_pending.add(child)
|
|
elif childstate == NODE_FAILED:
|
|
children_failed = True
|
|
|
|
if childstate <= NODE_EXECUTING:
|
|
children_not_ready.append(child)
|
|
|
|
# These nodes have not even been visited yet. Add
|
|
# them to the list so that on some next pass we can
|
|
# take a stab at evaluating them (or their children).
|
|
if children_not_visited:
|
|
if len(children_not_visited) > 1:
|
|
children_not_visited.reverse()
|
|
self.candidates.extend(self.order(children_not_visited))
|
|
|
|
# if T and children_not_visited:
|
|
# T.write(self.trace_message(' adding to candidates: %s' % map(str, children_not_visited)))
|
|
# T.write(self.trace_message(' candidates now: %s\n' % map(str, self.candidates)))
|
|
|
|
# Skip this node if any of its children have failed.
|
|
#
|
|
# This catches the case where we're descending a top-level
|
|
# target and one of our children failed while trying to be
|
|
# built by a *previous* descent of an earlier top-level
|
|
# target.
|
|
#
|
|
# It can also occur if a node is reused in multiple
|
|
# targets. One first descends though the one of the
|
|
# target, the next time occurs through the other target.
|
|
#
|
|
# Note that we can only have failed_children if the
|
|
# --keep-going flag was used, because without it the build
|
|
# will stop before diving in the other branch.
|
|
#
|
|
# Note that even if one of the children fails, we still
|
|
# added the other children to the list of candidate nodes
|
|
# to keep on building (--keep-going).
|
|
if children_failed:
|
|
for n in executor.get_action_targets():
|
|
n.set_state(NODE_FAILED)
|
|
|
|
if S: S.child_failed = S.child_failed + 1
|
|
if T: T.write(self.trace_message('****** %s\n' % self.trace_node(node)))
|
|
continue
|
|
|
|
if children_not_ready:
|
|
for child in children_not_ready:
|
|
# We're waiting on one or more derived targets
|
|
# that have not yet finished building.
|
|
if S: S.not_built = S.not_built + 1
|
|
|
|
# Add this node to the waiting parents lists of
|
|
# anything we're waiting on, with a reference
|
|
# count so we can be put back on the list for
|
|
# re-evaluation when they've all finished.
|
|
node.ref_count = node.ref_count + child.add_to_waiting_parents(node)
|
|
if T: T.write(self.trace_message(' adjusted ref count: %s, child %s' %
|
|
(self.trace_node(node), repr(str(child)))))
|
|
|
|
if T:
|
|
for pc in children_pending:
|
|
T.write(self.trace_message(' adding %s to the pending children set\n' %
|
|
self.trace_node(pc)))
|
|
self.pending_children = self.pending_children | children_pending
|
|
|
|
continue
|
|
|
|
# Skip this node if it has side-effects that are
|
|
# currently being built:
|
|
wait_side_effects = False
|
|
for se in executor.get_action_side_effects():
|
|
if se.get_state() == NODE_EXECUTING:
|
|
se.add_to_waiting_s_e(node)
|
|
wait_side_effects = True
|
|
|
|
if wait_side_effects:
|
|
if S: S.side_effects = S.side_effects + 1
|
|
continue
|
|
|
|
# The default when we've gotten through all of the checks above:
|
|
# this node is ready to be built.
|
|
if S: S.build = S.build + 1
|
|
if T: T.write(self.trace_message('Evaluating %s\n' %
|
|
self.trace_node(node)))
|
|
|
|
# For debugging only:
|
|
#
|
|
# try:
|
|
# self._validate_pending_children()
|
|
# except:
|
|
# self.ready_exc = sys.exc_info()
|
|
# return node
|
|
|
|
return node
|
|
|
|
return None
|
|
|
|
def next_task(self):
|
|
"""
|
|
Returns the next task to be executed.
|
|
|
|
This simply asks for the next Node to be evaluated, and then wraps
|
|
it in the specific Task subclass with which we were initialized.
|
|
"""
|
|
node = self._find_next_ready_node()
|
|
|
|
if node is None:
|
|
return None
|
|
|
|
executor = node.get_executor()
|
|
if executor is None:
|
|
return None
|
|
|
|
tlist = executor.get_all_targets()
|
|
|
|
task = self.tasker(self, tlist, node in self.original_top, node)
|
|
try:
|
|
task.make_ready()
|
|
except Exception as e :
|
|
# We had a problem just trying to get this task ready (like
|
|
# a child couldn't be linked to a VariantDir when deciding
|
|
# whether this node is current). Arrange to raise the
|
|
# exception when the Task is "executed."
|
|
self.ready_exc = sys.exc_info()
|
|
|
|
if self.ready_exc:
|
|
task.exception_set(self.ready_exc)
|
|
|
|
self.ready_exc = None
|
|
|
|
return task
|
|
|
|
def will_not_build(self, nodes, node_func=lambda n: None):
|
|
"""
|
|
Perform clean-up about nodes that will never be built. Invokes
|
|
a user defined function on all of these nodes (including all
|
|
of their parents).
|
|
"""
|
|
|
|
T = self.trace
|
|
|
|
pending_children = self.pending_children
|
|
|
|
to_visit = set(nodes)
|
|
pending_children = pending_children - to_visit
|
|
|
|
if T:
|
|
for n in nodes:
|
|
T.write(self.trace_message(' removing node %s from the pending children set\n' %
|
|
self.trace_node(n)))
|
|
try:
|
|
while len(to_visit):
|
|
node = to_visit.pop()
|
|
node_func(node)
|
|
|
|
# Prune recursion by flushing the waiting children
|
|
# list immediately.
|
|
parents = node.waiting_parents
|
|
node.waiting_parents = set()
|
|
|
|
to_visit = to_visit | parents
|
|
pending_children = pending_children - parents
|
|
|
|
for p in parents:
|
|
p.ref_count = p.ref_count - 1
|
|
if T: T.write(self.trace_message(' removing parent %s from the pending children set\n' %
|
|
self.trace_node(p)))
|
|
except KeyError:
|
|
# The container to_visit has been emptied.
|
|
pass
|
|
|
|
# We have the stick back the pending_children list into the
|
|
# taskmaster because the python 1.5.2 compatibility does not
|
|
# allow us to use in-place updates
|
|
self.pending_children = pending_children
|
|
|
|
def stop(self):
|
|
"""
|
|
Stops the current build completely.
|
|
"""
|
|
self.next_candidate = self.no_next_candidate
|
|
|
|
def cleanup(self):
|
|
"""
|
|
Check for dependency cycles.
|
|
"""
|
|
if not self.pending_children:
|
|
return
|
|
|
|
nclist = [(n, find_cycle([n], set())) for n in self.pending_children]
|
|
|
|
genuine_cycles = [
|
|
node for node,cycle in nclist
|
|
if cycle or node.get_state() != NODE_EXECUTED
|
|
]
|
|
if not genuine_cycles:
|
|
# All of the "cycles" found were single nodes in EXECUTED state,
|
|
# which is to say, they really weren't cycles. Just return.
|
|
return
|
|
|
|
desc = 'Found dependency cycle(s):\n'
|
|
for node, cycle in nclist:
|
|
if cycle:
|
|
desc = desc + " " + " -> ".join(map(str, cycle)) + "\n"
|
|
else:
|
|
desc = desc + \
|
|
" Internal Error: no cycle found for node %s (%s) in state %s\n" % \
|
|
(node, repr(node), StateString[node.get_state()])
|
|
|
|
raise SCons.Errors.UserError(desc)
|
|
|
|
# Local Variables:
|
|
# tab-width:4
|
|
# indent-tabs-mode:nil
|
|
# End:
|
|
# vim: set expandtab tabstop=4 shiftwidth=4:
|