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waf/playground/exclusive_link/excl.py
2015-08-28 21:37:09 +02:00

65 lines
1.5 KiB
Python

#! /usr/bin/env python
# encoding: utf-8
# Thomas Nagy, 2011-2015 (ita)
"""
Prevents link tasks from executing in parallel. This can be used to
improve the linker execution, which may use a lot of memory.
The variable 'MAX' represents the tasks able to run
concurrently (just one by default). The variable 'count'
is the amount of tasks of one kind being executed.
Different constraints can be enforced by changing the scope
of some variables. Remember that:
* the counter could be set on the class level
* the MAX amount of concurrent tasks can be more than 1
"""
from waflib.Utils import threading
from waflib import Task
lock = threading.Lock()
count = 0
MAX = 1
def make_exclusive(cls):
old_runnable_status = cls.runnable_status
def runnable_status(self):
global count, lock, MAX
ret = Task.ASK_LATER
if count >= MAX:
return ret
self.m1_excl = getattr(self, 'm1_excl', 0) + 1
ret = old_runnable_status(self)
self.m1_excl -= 1
if ret == Task.RUN_ME and not self.m1_excl:
lock.acquire()
count += 1
lock.release()
return ret
cls.runnable_status = runnable_status
old_run = cls.run
def run(self):
global count, lock
try:
self.m2_excl = getattr(self, 'm2_excl', 0) + 1
ret = old_run(self)
finally:
self.m2_excl -= 1
if not self.m2_excl:
lock.acquire()
count -= 1
lock.release()
return ret
cls.run = run
for x in 'cprogram cxxprogram cshlib cxxshlib cstlib cxxstlib fcprogram fcshlib fcstlib'.split():
if x in Task.classes:
make_exclusive(Task.classes[x])