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"""SCons.Sig
The Signature package for the scons software construction utility.
"""
#
# __COPYRIGHT__
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
import cPickle
import os
import os.path
import time
import SCons.Node
import SCons.Warnings
try:
import MD5
default_module = MD5
except ImportError:
import TimeStamp
default_module = TimeStamp
default_max_drift = 2*24*60*60
#XXX Get rid of the global array so this becomes re-entrant.
sig_files = []
SConsign_db = None
# 1 means use build signature for derived source files
# 0 means use content signature for derived source files
build_signature = 1
def write():
global sig_files
for sig_file in sig_files:
sig_file.write()
class SConsignEntry:
"""Objects of this type are pickled to the .sconsign file, so it
should only contain simple builtin Python datatypes and no methods.
This class is used to store cache information about nodes between
scons runs for efficiency, and to store the build signature for
nodes so that scons can determine if they are out of date. """
# setup the default value for various attributes:
# (We make the class variables so the default values won't get pickled
# with the instances, which would waste a lot of space)
timestamp = None
bsig = None
csig = None
implicit = None
class _SConsign:
"""
This is the controlling class for the signatures for the collection of
entries associated with a specific directory. The actual directory
association will be maintained by a subclass that is specific to
the underlying storage method. This class provides a common set of
methods for fetching and storing the individual bits of information
that make up signature entry.
"""
def __init__(self, module=None):
"""
module - the signature module being used
"""
if module is None:
self.module = default_calc.module
else:
self.module = module
self.entries = {}
self.dirty = 0
# A null .sconsign entry. We define this here so that it will
# be easy to keep this in sync if/whenever we change the type of
# information returned by the get() method, below.
null_siginfo = (None, None, None)
def get(self, filename):
"""
Get the .sconsign entry for a file
filename - the filename whose signature will be returned
returns - (timestamp, bsig, csig)
"""
entry = self.get_entry(filename)
return (entry.timestamp, entry.bsig, entry.csig)
def get_entry(self, filename):
"""
Create an entry for the filename and return it, or if one already exists,
then return it.
"""
try:
return self.entries[filename]
except:
return SConsignEntry()
def set_entry(self, filename, entry):
"""
Set the entry.
"""
self.entries[filename] = entry
self.dirty = 1
def set_csig(self, filename, csig):
"""
Set the csig .sconsign entry for a file
filename - the filename whose signature will be set
csig - the file's content signature
"""
entry = self.get_entry(filename)
entry.csig = csig
self.set_entry(filename, entry)
def set_bsig(self, filename, bsig):
"""
Set the csig .sconsign entry for a file
filename - the filename whose signature will be set
bsig - the file's built signature
"""
entry = self.get_entry(filename)
entry.bsig = bsig
self.set_entry(filename, entry)
def set_timestamp(self, filename, timestamp):
"""
Set the csig .sconsign entry for a file
filename - the filename whose signature will be set
timestamp - the file's timestamp
"""
entry = self.get_entry(filename)
entry.timestamp = timestamp
self.set_entry(filename, entry)
def get_implicit(self, filename):
"""Fetch the cached implicit dependencies for 'filename'"""
entry = self.get_entry(filename)
return entry.implicit
def set_implicit(self, filename, implicit):
"""Cache the implicit dependencies for 'filename'."""
entry = self.get_entry(filename)
if SCons.Util.is_String(implicit):
implicit = [implicit]
implicit = map(str, implicit)
entry.implicit = implicit
self.set_entry(filename, entry)
class SConsignDB(_SConsign):
"""
A _SConsign subclass that reads and writes signature information
from a global .sconsign.dbm file.
"""
def __init__(self, dir, module=None):
_SConsign.__init__(self, module)
self.dir = dir
try:
global SConsign_db
rawentries = SConsign_db[self.dir.path]
except KeyError:
pass
else:
try:
self.entries = cPickle.loads(rawentries)
if type(self.entries) is not type({}):
self.entries = {}
raise TypeError
except:
SCons.Warnings.warn(SCons.Warnings.CorruptSConsignWarning,
"Ignoring corrupt sconsign entry : %s"%self.dir.path)
global sig_files
sig_files.append(self)
def write(self):
if self.dirty:
global SConsign_db
SConsign_db[self.dir.path] = cPickle.dumps(self.entries, 1)
SConsign_db.sync()
class SConsignDir(_SConsign):
def __init__(self, fp=None, module=None):
"""
fp - file pointer to read entries from
module - the signature module being used
"""
_SConsign.__init__(self, module)
if fp:
self.entries = cPickle.load(fp)
if type(self.entries) is not type({}):
self.entries = {}
raise TypeError
class SConsignDirFile(SConsignDir):
"""
Encapsulates reading and writing a per-directory .sconsign file.
"""
def __init__(self, dir, module=None):
"""
dir - the directory for the file
module - the signature module being used
"""
self.dir = dir
self.sconsign = os.path.join(dir.path, '.sconsign')
try:
fp = open(self.sconsign, 'rb')
except:
fp = None
try:
SConsignDir.__init__(self, fp, module)
except:
SCons.Warnings.warn(SCons.Warnings.CorruptSConsignWarning,
"Ignoring corrupt .sconsign file: %s"%self.sconsign)
global sig_files
sig_files.append(self)
def write(self):
"""
Write the .sconsign file to disk.
Try to write to a temporary file first, and rename it if we
succeed. If we can't write to the temporary file, it's
probably because the directory isn't writable (and if so,
how did we build anything in this directory, anyway?), so
try to write directly to the .sconsign file as a backup.
If we can't rename, try to copy the temporary contents back
to the .sconsign file. Either way, always try to remove
the temporary file at the end.
"""
if self.dirty:
temp = os.path.join(self.dir.path, '.scons%d' % os.getpid())
try:
file = open(temp, 'wb')
fname = temp
except:
try:
file = open(self.sconsign, 'wb')
fname = self.sconsign
except:
return
cPickle.dump(self.entries, file, 1)
file.close()
if fname != self.sconsign:
try:
mode = os.stat(self.sconsign)[0]
os.chmod(self.sconsign, 0666)
os.unlink(self.sconsign)
except:
pass
try:
os.rename(fname, self.sconsign)
except:
open(self.sconsign, 'wb').write(open(fname, 'rb').read())
os.chmod(self.sconsign, mode)
try:
os.unlink(temp)
except:
pass
SConsignForDirectory = SConsignDirFile
def SConsignFile(name):
"""
Arrange for all signatures to be stored in a global .sconsign.dbm
file.
"""
global SConsign_db
if SConsign_db is None:
import anydbm
SConsign_db = anydbm.open(name, "c")
global SConsignForDirectory
SConsignForDirectory = SConsignDB
class Calculator:
"""
Encapsulates signature calculations and .sconsign file generating
for the build engine.
"""
def __init__(self, module=default_module, max_drift=default_max_drift):
"""
Initialize the calculator.
module - the signature module to use for signature calculations
max_drift - the maximum system clock drift used to determine when to
cache content signatures. A negative value means to never cache
content signatures. (defaults to 2 days)
"""
self.module = module
self.max_drift = max_drift
def bsig(self, node, cache=None):
"""
Generate a node's build signature, the digested signatures
of its dependency files and build information.
node - the node whose sources will be collected
cache - alternate node to use for the signature cache
returns - the build signature
This no longer handles the recursive descent of the
node's children's signatures. We expect that they're
already built and updated by someone else, if that's
what's wanted.
"""
if cache is None: cache = node
bsig = cache.get_bsig()
if bsig is not None:
return bsig
children = node.children()
# double check bsig, because the call to childre() above may
# have set it:
bsig = cache.get_bsig()
if bsig is not None:
return bsig
sigs = map(lambda n, c=self: n.calc_signature(c), children)
if node.has_builder():
sigs.append(self.module.signature(node.get_executor()))
bsig = self.module.collect(filter(lambda x: not x is None, sigs))
cache.set_bsig(bsig)
# don't store the bsig here, because it isn't accurate until
# the node is actually built.
return bsig
def csig(self, node, cache=None):
"""
Generate a node's content signature, the digested signature
of its content.
node - the node
cache - alternate node to use for the signature cache
returns - the content signature
"""
if cache is None: cache = node
csig = cache.get_csig()
if csig is not None:
return csig
if self.max_drift >= 0:
oldtime, oldbsig, oldcsig = node.get_prevsiginfo()
else:
oldtime, oldbsig, oldcsig = _SConsign.null_siginfo
mtime = node.get_timestamp()
if (oldtime and oldcsig and oldtime == mtime):
# use the signature stored in the .sconsign file
csig = oldcsig
# Set the csig here so it doesn't get recalculated unnecessarily
# and so it's set when the .sconsign file gets written
cache.set_csig(csig)
else:
csig = self.module.signature(node)
# Set the csig here so it doesn't get recalculated unnecessarily
# and so it's set when the .sconsign file gets written
cache.set_csig(csig)
if self.max_drift >= 0 and (time.time() - mtime) > self.max_drift:
node.store_csig()
node.store_timestamp()
return csig
def current(self, node, newsig):
"""
Check if a signature is up to date with respect to a node.
node - the node whose signature will be checked
newsig - the (presumably current) signature of the file
returns - 1 if the file is current with the specified signature,
0 if it isn't
"""
if node.always_build:
return 0
oldtime, oldbsig, oldcsig = node.get_prevsiginfo()
if not node.has_builder() and node.get_timestamp() == oldtime:
return 1
return self.module.current(newsig, oldbsig)
default_calc = Calculator()
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