forks/apenwarr-redo
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Change locking stuff from fifos to fcntl.lockf().

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This should reduce filesystem grinding a bit, and makes the code simpler.
It's also theoretically a bit more portable, since I'm guessing fifo
semantics aren't the same on win32 if we ever get there.

Also, a major problem with the old fifo-based system is that if a redo
process died without cleaning up after itself, it wouldn't delete its
lockfiles, so we had to wipe them all at the beginning of each build.  Now
we don't; in theory, you can now have multiple copies of redo poking at the
same tree at the same time and not stepping on each other.
This commit is contained in:
Avery Pennarun 2010-12-10 02:58:13 -08:00
commit 84169c5d27
2 changed files with 58 additions and 79 deletions
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49
builder.py
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@ -43,8 +43,9 @@ def _try_stat(filename):
class BuildJob:
def __init__(self, t, lock, shouldbuildfunc, donefunc):
self.t = t
def __init__(self, t, sf, lock, shouldbuildfunc, donefunc):
self.t = t # original target name, not relative to vars.BASE
self.sf = sf
self.tmpname = '%s.redo.tmp' % t
self.lock = lock
self.shouldbuildfunc = shouldbuildfunc
@ -54,13 +55,13 @@ class BuildJob:
def start(self):
assert(self.lock.owned)
t = self.t
f = state.File(name=t)
sf = self.sf
tmpname = self.tmpname
if not self.shouldbuildfunc(t):
# target doesn't need to be built; skip the whole task
return self._after2(0)
if (os.path.exists(t) and not os.path.exists(t + '/.')
and not f.is_generated):
and not sf.is_generated):
# an existing source file that was not generated by us.
# This step is mentioned by djb in his notes.
# For example, a rule called default.c.do could be used to try
@ -70,16 +71,16 @@ class BuildJob:
# of redo? That would make it easy for someone to override a
# file temporarily, and could be undone by deleting the file.
debug2("-- static (%r)\n" % t)
f.set_static()
f.save()
sf.set_static()
sf.save()
return self._after2(0)
f.zap_deps()
(dofile, basename, ext) = _find_do_file(f)
sf.zap_deps()
(dofile, basename, ext) = _find_do_file(sf)
if not dofile:
if os.path.exists(t):
f.is_generated = False
f.set_static()
f.save()
sf.is_generated = False
sf.set_static()
sf.save()
return self._after2(0)
else:
err('no rule to make %r\n' % t)
@ -100,8 +101,8 @@ class BuildJob:
if vars.VERBOSE or vars.XTRACE: log_('\n')
log('%s\n' % _nice(t))
self.argv = argv
f.is_generated = True
f.save()
sf.is_generated = True
sf.save()
dof = state.File(name=dofile)
dof.set_static()
dof.save()
@ -165,14 +166,14 @@ class BuildJob:
os.rename(tmpname, t)
else:
unlink(tmpname)
sf = state.File(name=t)
sf = self.sf
sf.is_generated=True
sf.update_stamp()
sf.set_changed()
sf.save()
else:
unlink(tmpname)
sf = state.File(name=t)
sf = self.sf
sf.stamp = None
sf.set_changed()
sf.save()
@ -219,18 +220,19 @@ def main(targets, shouldbuildfunc):
err('.redo directory disappeared; cannot continue.\n')
retcode[0] = 205
break
lock = state.Lock(t)
f = state.File(name=t)
lock = state.Lock(f.id)
lock.trylock()
if not lock.owned:
if vars.DEBUG_LOCKS:
log('%s (locked...)\n' % _nice(t))
locked.append(t)
locked.append((f.id,t))
else:
BuildJob(t, lock, shouldbuildfunc, done).start()
BuildJob(t, f, lock, shouldbuildfunc, done).start()
# Now we've built all the "easy" ones. Go back and just wait on the
# remaining ones one by one. This is technically non-optimal; we could
# use select.select() to wait on more than one at a time. But it should
# remaining ones one by one. This is non-optimal; we could go faster if
# we could wait on multiple locks at once. But it should
# be rare enough that it doesn't matter, and the logic is easier this way.
while locked or jwack.running():
state.commit()
@ -244,8 +246,8 @@ def main(targets, shouldbuildfunc):
err('.redo directory disappeared; cannot continue.\n')
retcode[0] = 205
break
t = locked.pop(0)
lock = state.Lock(t)
fid,t = locked.pop(0)
lock = state.Lock(fid)
lock.waitlock()
assert(lock.owned)
if vars.DEBUG_LOCKS:
@ -255,6 +257,7 @@ def main(targets, shouldbuildfunc):
retcode[0] = 2
lock.unlock()
else:
BuildJob(t, lock, shouldbuildfunc, done).start()
BuildJob(t, state.File(id=fid), lock,
shouldbuildfunc, done).start()
state.commit()
return retcode[0]