Added the 'have_run' dictionary to Distribution, and changed
'run_command()' to refer to it before attempting to run a command --
that way, command classes can freely invoke other commands without fear
of duplicate execution.
Beefed up some comments and docstrings.
diff --git a/Lib/distutils/core.py b/Lib/distutils/core.py
index 4b8c783..8a6cf72 100644
--- a/Lib/distutils/core.py
+++ b/Lib/distutils/core.py
@@ -136,6 +136,10 @@
self.licence = None
self.description = None
+ # 'cmdclass' maps command names to class objects, so we
+ # can 1) quickly figure out which class to instantiate when
+ # we need to create a new command object, and 2) have a way
+ # for the client to override command classes
self.cmdclass = {}
# The rest of these are really the business of various commands,
@@ -152,9 +156,23 @@
setattr (self, k, attrs[k])
# And now initialize bookkeeping stuff that can't be supplied by
- # the caller at all
+ # the caller at all. 'command_obj' maps command names to
+ # Command instances -- that's how we enforce that every command
+ # class is a singleton.
self.command_obj = {}
+ # 'have_run' maps command names to boolean values; it keeps track
+ # of whether we have actually run a particular command, to make it
+ # cheap to "run" a command whenever we think we might need to -- if
+ # it's already been done, no need for expensive filesystem
+ # operations, we just check the 'have_run' dictionary and carry on.
+ # It's only safe to query 'have_run' for a command class
+ # that has been instantiated -- a false value will be put inserted
+ # when the command object is created, and replaced with a true
+ # value when the command is succesfully run. Thus it's
+ # probably best to use '.get()' rather than a straight lookup.
+ self.have_run = {}
+
# __init__ ()
@@ -211,6 +229,7 @@
# attribute, but we're not enforcing that anywhere!
args = fancy_getopt (cmd_obj.options, cmd_obj, args[1:])
self.command_obj[command] = cmd_obj
+ self.have_run[command] = 0
# while args
@@ -347,12 +366,23 @@
# -- Methods that operate on its Commands --------------------------
def run_command (self, command):
- """Create a command object for 'command' if necessary, and
- run the command by invoking its 'run()' method."""
+
+ """Do whatever it takes to run a command (including nothing at all,
+ if the command has already been run). Specifically: if we have
+ already created and run the command named by 'command', return
+ silently without doing anything. If the command named by
+ 'command' doesn't even have a command object yet, create one.
+ Then invoke 'run()' on that command object (or an existing
+ one)."""
+
+ # Already been here, done that? then return silently.
+ if self.have_run.get (command):
+ return
self.announce ("running " + command)
cmd_obj = self.find_command_obj (command)
cmd_obj.run ()
+ self.have_run[command] = 1
def get_command_option (self, command, option):