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 = [x.decode('hex') for x 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 def commit_oid(item):
  42     if isinstance(item, vfs.Commit):
  43         return item.coid
  44     assert isinstance(item, vfs.RevList)
  45     return item.oid
  46
  47 def rm_saves(saves, writer):
  48     assert(saves)
  49     first_branch_item = saves[0][1]
  50     for save, branch in saves: # Be certain they're all on the same branch
  51         assert(branch == first_branch_item)
  52     rm_commits = frozenset([commit_oid(save) for save, branch in saves])
  53     orig_tip = commit_oid(first_branch_item)
  54     new_tip = filter_branch(orig_tip.encode('hex'),
  55                             lambda x: x in rm_commits,
  56                             writer)
  57     assert(orig_tip)
  58     assert(new_tip != orig_tip)
  59     return orig_tip, new_tip
  60
  61
  62 def dead_items(repo, paths):
  63     """Return an optimized set of removals, reporting errors via
  64     add_error, and if there are any errors, return None, None."""
  65     dead_branches = {}
  66     dead_saves = {}
  67     # Scan for bad requests, and opportunities to optimize
  68     for path in paths:
  69         try:
  70             resolved = vfs.lresolve(repo, path)
  71         except vfs.IOError as e:
  72             add_error(e)
  73             continue
  74         else:
  75             leaf_name, leaf_item = resolved[-1]
  76             if not leaf_item:
  77                 add_error('error: cannot access %r in %r'
  78                           % ('/'.join(name for name, item in resolved),
  79                              path))
  80                 continue
  81             if isinstance(leaf_item, vfs.RevList):  # rm /foo
  82                 branchname = leaf_name
  83                 dead_branches[branchname] = leaf_item
  84                 dead_saves.pop(branchname, None)  # rm /foo obviates rm /foo/bar
  85             elif isinstance(leaf_item, vfs.Commit):  # rm /foo/bar
  86                 if leaf_name == 'latest':
  87                     add_error("error: cannot delete 'latest' symlink")
  88                 else:
  89                     branchname, branchitem = resolved[-2]
  90                     if branchname not in dead_branches:
  91                         dead = leaf_item, branchitem
  92                         dead_saves.setdefault(branchname, []).append(dead)
  93             else:
  94                 add_error("don't know how to remove %r yet" % path)
  95     if saved_errors:
  96         return None, None
  97     return dead_branches, dead_saves
  98
  99
 100 def bup_rm(repo, paths, compression=6, verbosity=None):
 101     dead_branches, dead_saves = dead_items(repo, paths)
 102     die_if_errors('not proceeding with any removals\n')
 103
 104     updated_refs = {}  # ref_name -> (original_ref, tip_commit(bin))
 105
 106     for branchname, branchitem in dead_branches.iteritems():
 107         ref = 'refs/heads/' + branchname
 108         assert(not ref in updated_refs)
 109         updated_refs[ref] = (branchitem.oid, None)
 110
 111     if dead_saves:
 112         writer = git.PackWriter(compression_level=compression)
 113         try:
 114             for branch, saves in dead_saves.iteritems():
 115                 assert(saves)
 116                 updated_refs['refs/heads/' + branch] = rm_saves(saves, writer)
 117         except:
 118             if writer:
 119                 writer.abort()
 120             raise
 121         else:
 122             if writer:
 123                 # Must close before we can update the ref(s) below.
 124                 writer.close()
 125
 126     # Only update the refs here, at the very end, so that if something
 127     # goes wrong above, the old refs will be undisturbed.  Make an attempt
 128     # to update each ref.
 129     for ref_name, info in updated_refs.iteritems():
 130         orig_ref, new_ref = info
 131         try:
 132             if not new_ref:
 133                 git.delete_ref(ref_name, orig_ref.encode('hex'))
 134             else:
 135                 git.update_ref(ref_name, new_ref, orig_ref)
 136                 if verbosity:
 137                     new_hex = new_ref.encode('hex')
 138                     if orig_ref:
 139                         orig_hex = orig_ref.encode('hex')
 140                         log('updated %r (%s -> %s)\n'
 141                             % (ref_name, orig_hex, new_hex))
 142                     else:
 143                         log('updated %r (%s)\n' % (ref_name, new_hex))
 144         except (git.GitError, ClientError) as ex:
 145             if new_ref:
 146                 add_error('while trying to update %r (%s -> %s): %s'
 147                           % (ref_name, orig_ref, new_ref, ex))
 148             else:
 149                 add_error('while trying to delete %r (%s): %s'
 150                           % (ref_name, orig_ref, ex))