path: root/lib/git/objects/submodule/root.py

from base import Submodule
from util import (
					find_first_remote_branch
				)
from git.exc import InvalidGitRepositoryError
import git

import sys

__all__ = ["RootModule"]

	
class RootModule(Submodule):
	"""A (virtual) Root of all submodules in the given repository. It can be used
	to more easily traverse all submodules of the master repository"""
	
	__slots__ = tuple()
	
	k_root_name = '__ROOT__'
	
	def __init__(self, repo):
		# repo, binsha, mode=None, path=None, name = None, parent_commit=None, url=None, ref=None)
		super(RootModule, self).__init__(
										repo, 
										binsha = self.NULL_BIN_SHA, 
										mode = self.k_default_mode, 
										path = '', 
										name = self.k_root_name, 
										parent_commit = repo.head.commit,
										url = '',
										branch_path = git.Head.to_full_path(self.k_head_default)
										)
		
	
	def _clear_cache(self):
		"""May not do anything"""
		pass
	
	#{ Interface 
	
	def update(self, previous_commit=None, recursive=True, force_remove=False, init=True, to_latest_revision=False):
		"""Update the submodules of this repository to the current HEAD commit.
		This method behaves smartly by determining changes of the path of a submodules
		repository, next to changes to the to-be-checked-out commit or the branch to be 
		checked out. This works if the submodules ID does not change.
		Additionally it will detect addition and removal of submodules, which will be handled
		gracefully.
		
		:param previous_commit: If set to a commit'ish, the commit we should use 
			as the previous commit the HEAD pointed to before it was set to the commit it points to now. 
			If None, it defaults to ORIG_HEAD otherwise, or the parent of the current
			commit if it is not given
		:param recursive: if True, the children of submodules will be updated as well
			using the same technique
		:param force_remove: If submodules have been deleted, they will be forcibly removed.
			Otherwise the update may fail if a submodule's repository cannot be deleted as 
			changes have been made to it (see Submodule.update() for more information)
		:param init: If we encounter a new module which would need to be initialized, then do it.
		:param to_latest_revision: If True, instead of checking out the revision pointed to 
			by this submodule's sha, the checked out tracking branch will be merged with the 
			newest remote branch fetched from the repository's origin"""
		if self.repo.bare:
			raise InvalidGitRepositoryError("Cannot update submodules in bare repositories")
		# END handle bare
		
		repo = self.repo
		
		# HANDLE COMMITS
		##################
		cur_commit = repo.head.commit
		if previous_commit is None:
			symref = repo.head.orig_head()
			try:
				previous_commit = symref.commit
			except Exception:
				pcommits = cur_commit.parents
				if pcommits:
					previous_commit = pcommits[0]
				else:
					# in this special case, we just diff against ourselve, which
					# means exactly no change
					previous_commit = cur_commit
				# END handle initial commit
			# END no ORIG_HEAD
		else:
			previous_commit = repo.commit(previous_commit)	 # obtain commit object 
		# END handle previous commit
		
		
		psms = self.list_items(repo, parent_commit=previous_commit)
		sms = self.list_items(self.module())
		spsms = set(psms)
		ssms = set(sms)
		
		# HANDLE REMOVALS
		###################
		for rsm in (spsms - ssms):
			# fake it into thinking its at the current commit to allow deletion
			# of previous module. Trigger the cache to be updated before that
			#rsm.url
			rsm._parent_commit = repo.head.commit
			rsm.remove(configuration=False, module=True, force=force_remove)
		# END for each removed submodule
		
		# HANDLE PATH RENAMES
		#####################
		# url changes + branch changes
		for csm in (spsms & ssms):
			psm = psms[csm.name]
			sm = sms[csm.name]
			
			if sm.path != psm.path and psm.module_exists():
				# move the module to the new path
				psm.move(sm.path, module=True, configuration=False)
			# END handle path changes
			
			if sm.module_exists():
				# handle url change
				if sm.url != psm.url:
					# Add the new remote, remove the old one
					# This way, if the url just changes, the commits will not 
					# have to be re-retrieved
					nn = '__new_origin__'
					smm = sm.module()
					rmts = smm.remotes
					
					# don't do anything if we already have the url we search in place
					if len([r for r in rmts if r.url == sm.url]) == 0:
						
						
						assert nn not in [r.name for r in rmts]
						smr = smm.create_remote(nn, sm.url)
						smr.fetch()
						
						# If we have a tracking branch, it should be available
						# in the new remote as well.
						if len([r for r in smr.refs if r.remote_head == sm.branch_name]) == 0:
							raise ValueError("Submodule branch named %r was not available in new submodule remote at %r" % (sm.branch_name, sm.url))
						# END head is not detached
						
						# now delete the changed one
						rmt_for_deletion = None
						for remote in rmts:
							if remote.url == psm.url:
								rmt_for_deletion = remote
								break
							# END if urls match
						# END for each remote
						
						# if we didn't find a matching remote, but have exactly one, 
						# we can safely use this one
						if rmt_for_deletion is None:
							if len(rmts) == 1:
								rmt_for_deletion = rmts[0]
							else:
								# if we have not found any remote with the original url
								# we may not have a name. This is a special case, 
								# and its okay to fail here
								# Alternatively we could just generate a unique name and leave all
								# existing ones in place
								raise InvalidGitRepositoryError("Couldn't find original remote-repo at url %r" % psm.url)
							#END handle one single remote
						# END handle check we found a remote
						
						orig_name = rmt_for_deletion.name
						smm.delete_remote(rmt_for_deletion)
						# NOTE: Currently we leave tags from the deleted remotes
						# as well as separate tracking branches in the possibly totally 
						# changed repository ( someone could have changed the url to 
						# another project ). At some point, one might want to clean
						# it up, but the danger is high to remove stuff the user
						# has added explicitly
						
						# rename the new remote back to what it was
						smr.rename(orig_name)
						
						# early on, we verified that the our current tracking branch
						# exists in the remote. Now we have to assure that the 
						# sha we point to is still contained in the new remote
						# tracking branch.
						smsha = sm.binsha
						found = False
						rref = smr.refs[self.branch_name]
						for c in rref.commit.traverse():
							if c.binsha == smsha:
								found = True
								break
							# END traverse all commits in search for sha
						# END for each commit
						
						if not found:
							# adjust our internal binsha to use the one of the remote
							# this way, it will be checked out in the next step
							# This will change the submodule relative to us, so 
							# the user will be able to commit the change easily
							print >> sys.stderr, "WARNING: Current sha %s was not contained in the tracking branch at the new remote, setting it the the remote's tracking branch" % sm.hexsha
							sm.binsha = rref.commit.binsha
						#END reset binsha
						
						#NOTE: All checkout is performed by the base implementation of update
						
					# END skip remote handling if new url already exists in module
				# END handle url
				
				if sm.branch_path != psm.branch_path:
					# finally, create a new tracking branch which tracks the 
					# new remote branch
					smm = sm.module()
					smmr = smm.remotes
					try:
						tbr = git.Head.create(smm, sm.branch_name)
					except git.GitCommandError, e:
						if e.status != 128:
							raise
						#END handle something unexpected
						
						# ... or reuse the existing one
						tbr = git.Head(smm, sm.branch_path)
					#END assure tracking branch exists
					
					tbr.set_tracking_branch(find_first_remote_branch(smmr, sm.branch_name))
					# figure out whether the previous tracking branch contains
					# new commits compared to the other one, if not we can 
					# delete it.
					try:
						tbr = find_first_remote_branch(smmr, psm.branch_name)
						if len(smm.git.cherry(tbr, psm.branch)) == 0:
							psm.branch.delete(smm, psm.branch)
						#END delete original tracking branch if there are no changes
					except InvalidGitRepositoryError:
						# ignore it if the previous branch couldn't be found in the
						# current remotes, this just means we can't handle it
						pass
					# END exception handling
					
					#NOTE: All checkout is done in the base implementation of update
					
				#END handle branch
			#END handle 
		# END for each common submodule 
		
		# FINALLY UPDATE ALL ACTUAL SUBMODULES
		######################################
		for sm in sms:
			# update the submodule using the default method
			sm.update(recursive=False, init=init, to_latest_revision=to_latest_revision)
			
			# update recursively depth first - question is which inconsitent 
			# state will be better in case it fails somewhere. Defective branch
			# or defective depth. The RootSubmodule type will never process itself, 
			# which was done in the previous expression
			if recursive:
				type(self)(sm.module()).update(recursive=True, force_remove=force_remove, 
											init=init, to_latest_revision=to_latest_revision)
			#END handle recursive
		# END for each submodule to update

	def module(self):
		""":return: the actual repository containing the submodules"""
		return self.repo
	#} END interface
#} END classes