diff options
Diffstat (limited to 'indra')
| -rwxr-xr-x | indra/lib/python/indra/util/llmanifest.py | 82 |
1 files changed, 75 insertions, 7 deletions
diff --git a/indra/lib/python/indra/util/llmanifest.py b/indra/lib/python/indra/util/llmanifest.py index d4e61aedd1..7050ce43b7 100755 --- a/indra/lib/python/indra/util/llmanifest.py +++ b/indra/lib/python/indra/util/llmanifest.py @@ -376,12 +376,30 @@ class LLManifest(object): self.excludes.append(glob) def prefix(self, src='', build=None, dst=None): - """ Pushes a prefix onto the stack. Until end_prefix is - called, all relevant method calls (esp. to path()) will prefix - paths with the entire prefix stack. Source and destination - prefixes can be different, though if only one is provided they - are both equal. To specify a no-op, use an empty string, not - None.""" + """ + Usage: + + with self.prefix(...args as described...): + self.path(...) + + For the duration of the 'with' block, pushes a prefix onto the stack. + Within that block, all relevant method calls (esp. to path()) will + prefix paths with the entire prefix stack. Source and destination + prefixes can be different, though if only one is provided they are + both equal. To specify a no-op, use an empty string, not None. + + Also supports the older (pre-Python-2.5) syntax: + + if self.prefix(...args as described...): + self.path(...) + self.end_prefix(...) + + Before the arrival of the 'with' statement, one was required to code + self.prefix() and self.end_prefix() in matching pairs to push and to + pop the prefix stacks, respectively. The older prefix() method + returned True specifically so that the caller could indent the + relevant block of code with 'if', just for aesthetic purposes. + """ if dst is None: dst = src if build is None: @@ -390,7 +408,57 @@ class LLManifest(object): self.artwork_prefix.append(src) self.build_prefix.append(build) self.dst_prefix.append(dst) - return True # so that you can wrap it in an if to get indentation + + # The above code is unchanged from the original implementation. What's + # new is the return value. We're going to return an instance of + # PrefixManager that binds this LLManifest instance and Does The Right + # Thing on exit. + return self.PrefixManager(self) + + class PrefixManager(object): + def __init__(self, manifest): + self.manifest = manifest + # stack attributes we manage in this LLManifest (sub)class + # instance + stacks = ("src_prefix", "artwork_prefix", "build_prefix", "dst_prefix") + # If the caller wrote: + # with self.prefix(...): + # as intended, then bind the state of each prefix stack as it was + # just BEFORE the call to prefix(). Since prefix() appended an + # entry to each prefix stack, capture len()-1. + self.prevlen = { stack: len(getattr(self.manifest, stack)) - 1 + for stack in stacks } + + def __nonzero__(self): + # If the caller wrote: + # if self.prefix(...): + # then a value of this class had better evaluate as 'True'. + return True + + def __enter__(self): + # nobody uses 'with self.prefix(...) as variable:' + return None + + def __exit__(self, type, value, traceback): + # First, if the 'with' block raised an exception, just propagate. + # Do NOT swallow it. + if type is not None: + return False + + # Okay, 'with' block completed successfully. Restore previous + # state of each of the prefix stacks in self.stacks. + # Note that we do NOT simply call pop() on them as end_prefix() + # does. This is to cope with the possibility that the coder + # changed 'if self.prefix(...):' to 'with self.prefix(...):' yet + # forgot to remove the self.end_prefix(...) call at the bottom of + # the block. In that case, calling pop() again would be Bad! But + # if we restore the length of each stack to what it was before the + # current prefix() block, it doesn't matter whether end_prefix() + # was called or not. + for stack, prevlen in self.prevlen.items(): + # find the attribute in 'self.manifest' named by 'stack', and + # truncate that list back to 'prevlen' + del getattr(self.manifest, stack)[prevlen:] def end_prefix(self, descr=None): """Pops a prefix off the stack. If given an argument, checks |