lib/bup/rm.py

   1
   2 import sys
   3
   4 from bup import git, vfs
   5 from bup.client import ClientError
   6 from bup.git import get_commit_items
   7 from bup.helpers import add_error, die_if_errors, log, saved_errors
   8
   9
  10 def append_commit(hash, parent, cp, writer):
  11     ci = get_commit_items(hash, cp)
  12     tree = ci.tree.decode('hex')
  13     author = '%s <%s>' % (ci.author_name, ci.author_mail)
  14     committer = '%s <%s>' % (ci.committer_name, ci.committer_mail)
  15     c = writer.new_commit(tree, parent,
  16                           author, ci.author_sec, ci.author_offset,
  17                           committer, ci.committer_sec, ci.committer_offset,
  18                           ci.message)
  19     return c, tree
  20
  21
  22 def filter_branch(tip_commit_hex, exclude, writer):
  23     # May return None if everything is excluded.
  24     commits = [c for _, c in git.rev_list(tip_commit_hex)]
  25     commits.reverse()
  26     last_c, tree = None, None
  27     # Rather than assert that we always find an exclusion here, we'll
  28     # just let the StopIteration signal the error.
  29     first_exclusion = next(i for i, c in enumerate(commits) if exclude(c))
  30     if first_exclusion != 0:
  31         last_c = commits[first_exclusion - 1]
  32         tree = get_commit_items(last_c.encode('hex'),
  33                                 git.cp()).tree.decode('hex')
  34         commits = commits[first_exclusion:]
  35     for c in commits:
  36         if exclude(c):
  37             continue
  38         last_c, tree = append_commit(c.encode('hex'), last_c, git.cp(), writer)
  39     return last_c
  40
  41
  42 def rm_saves(saves, writer):
  43     assert(saves)
  44     branch_node = saves[0].parent
  45     for save in saves: # Be certain they're all on the same branch
  46         assert(save.parent == branch_node)
  47     rm_commits = frozenset([x.dereference().hash for x in saves])
  48     orig_tip = branch_node.hash
  49     new_tip = filter_branch(orig_tip.encode('hex'),
  50                             lambda x: x in rm_commits,
  51                             writer)
  52     assert(orig_tip)
  53     assert(new_tip != orig_tip)
  54     return orig_tip, new_tip
  55
  56
  57 def dead_items(vfs_top, paths):
  58     """Return an optimized set of removals, reporting errors via
  59     add_error, and if there are any errors, return None, None."""
  60     dead_branches = {}
  61     dead_saves = {}
  62     # Scan for bad requests, and opportunities to optimize
  63     for path in paths:
  64         try:
  65             n = vfs_top.lresolve(path)
  66         except vfs.NodeError as e:
  67             add_error('unable to resolve %s: %s' % (path, e))
  68         else:
  69             if isinstance(n, vfs.BranchList): # rm /foo
  70                 branchname = n.name
  71                 dead_branches[branchname] = n
  72                 dead_saves.pop(branchname, None) # rm /foo obviates rm /foo/bar
  73             elif isinstance(n, vfs.FakeSymlink) and isinstance(n.parent,
  74                                                                vfs.BranchList):
  75                 if n.name == 'latest':
  76                     add_error("error: cannot delete 'latest' symlink")
  77                 else:
  78                     branchname = n.parent.name
  79                     if branchname not in dead_branches:
  80                         dead_saves.setdefault(branchname, []).append(n)
  81             else:
  82                 add_error("don't know how to remove %r yet" % n.fullname())
  83     if saved_errors:
  84         return None, None
  85     return dead_branches, dead_saves
  86
  87
  88 def bup_rm(paths, compression=6, verbosity=None):
  89     root = vfs.RefList(None)
  90
  91     dead_branches, dead_saves = dead_items(root, paths)
  92     die_if_errors('not proceeding with any removals\n')
  93
  94     updated_refs = {}  # ref_name -> (original_ref, tip_commit(bin))
  95
  96     for branch, node in dead_branches.iteritems():
  97         ref = 'refs/heads/' + branch
  98         assert(not ref in updated_refs)
  99         updated_refs[ref] = (node.hash, None)
 100
 101     if dead_saves:
 102         writer = git.PackWriter(compression_level=compression)
 103         try:
 104             for branch, saves in dead_saves.iteritems():
 105                 assert(saves)
 106                 updated_refs['refs/heads/' + branch] = rm_saves(saves, writer)
 107         except:
 108             if writer:
 109                 writer.abort()
 110             raise
 111         else:
 112             if writer:
 113                 # Must close before we can update the ref(s) below.
 114                 writer.close()
 115
 116     # Only update the refs here, at the very end, so that if something
 117     # goes wrong above, the old refs will be undisturbed.  Make an attempt
 118     # to update each ref.
 119     for ref_name, info in updated_refs.iteritems():
 120         orig_ref, new_ref = info
 121         try:
 122             if not new_ref:
 123                 git.delete_ref(ref_name, orig_ref.encode('hex'))
 124             else:
 125                 git.update_ref(ref_name, new_ref, orig_ref)
 126                 if verbosity:
 127                     new_hex = new_ref.encode('hex')
 128                     if orig_ref:
 129                         orig_hex = orig_ref.encode('hex')
 130                         log('updated %r (%s -> %s)\n'
 131                             % (ref_name, orig_hex, new_hex))
 132                     else:
 133                         log('updated %r (%s)\n' % (ref_name, new_hex))
 134         except (git.GitError, ClientError) as ex:
 135             if new_ref:
 136                 add_error('while trying to update %r (%s -> %s): %s'
 137                           % (ref_name, orig_ref, new_ref, ex))
 138             else:
 139                 add_error('while trying to delete %r (%s): %s'
 140                           % (ref_name, orig_ref, ex))