lib/bup/rm.py

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