import cStringIO
import cPickle as pickle
import os
import sys
import tempfile
import traceback

from mercurial import context
from mercurial import hg
from mercurial import ui
from mercurial import util
from mercurial import revlog
from mercurial import node
from svn import delta
from svn import core

import svnexternals
import util as our_util

def pickle_atomic(data, file_path, dir=None):
    """pickle some data to a path atomically.

    This is present because I kept corrupting my revmap by managing to hit ^C
    during the pickle of that file.
    """
    try:
        f, path = tempfile.mkstemp(prefix='pickling', dir=dir)
        f = os.fdopen(f, 'w')
        pickle.dump(data, f)
        f.close()
    except: #pragma: no cover
        raise
    else:
        util.rename(path, file_path)

def stash_exception_on_self(fn):
    """Stash any exception raised in the method on self.

    This is required because the SWIG bindings just mutate any exception into
    a generic Subversion exception with no way of telling what the original was.
    This allows the editor object to notice when you try and commit and really
    got an exception in the replay process.
    """
    def fun(self, *args, **kwargs):
        try:
            return fn(self, *args, **kwargs)
        except: #pragma: no cover
            if not hasattr(self, '_exception_info'):
                self._exception_info = sys.exc_info()
            raise
    return fun


class HgChangeReceiver(delta.Editor):
    def add_to_revmap(self, revnum, branch, node_hash):
        f = open(self.revmap_file, 'a')
        f.write(str(revnum) + ' ' + node.hex(node_hash) + ' ' + (branch or '') + '\n')
        f.flush()
        f.close()
        self.revmap[revnum, branch] = node_hash

    def __init__(self, path=None, repo=None, ui_=None,
                 subdir='', author_host='',
                 tag_locations=['tags'],
                 authors=None,
                 filemap=None):
        """path is the path to the target hg repo.

        subdir is the subdirectory of the edits *on the svn server*.
        It is needed for stripping paths off in certain cases.
        """
        if not ui_:
            ui_ = ui.ui()
        self.ui = ui_
        if repo:
            self.repo = repo
            self.path = os.path.normpath(os.path.join(self.repo.path, '..'))
        elif path:
            self.path = path
            self.__setup_repo(path)
        else: #pragma: no cover
            raise TypeError("Expected either path or repo argument")

        self.subdir = subdir
        if self.subdir and self.subdir[0] == '/':
            self.subdir = self.subdir[1:]
        self.revmap = {}
        if os.path.exists(self.revmap_file):
            self.revmap = our_util.parse_revmap(self.revmap_file)
        self.branches = {}
        if os.path.exists(self.branch_info_file):
            f = open(self.branch_info_file)
            self.branches = pickle.load(f)
            f.close()
        self.tags = {}
        if os.path.exists(self.tag_info_file):
            f = open(self.tag_info_file)
            self.tags = pickle.load(f)
            f.close()
        if os.path.exists(self.tag_locations_file):
            f = open(self.tag_locations_file)
            self.tag_locations = pickle.load(f)
            f.close()
        else:
            self.tag_locations = tag_locations
        pickle_atomic(self.tag_locations, self.tag_locations_file,
                      self.meta_data_dir)

        self.clear_current_info()
        self.author_host = author_host
        self.authors = {}
        if os.path.exists(self.authors_file):
            self.readauthors(self.authors_file)
        if authors and os.path.exists(authors):
            self.readauthors(authors)
        if self.authors:
            self.writeauthors()
        self.includepaths = {}
        self.excludepaths = {}
        if filemap and os.path.exists(filemap):
            self.readfilemap(filemap)

    def __setup_repo(self, repo_path):
        """Verify the repo is going to work out for us.

        This method will fail an assertion if the repo exists but doesn't have
        the Subversion metadata.
        """
        if os.path.isdir(repo_path) and len(os.listdir(repo_path)):
            self.repo = hg.repository(self.ui, repo_path)
            assert os.path.isfile(self.revmap_file)
            assert os.path.isfile(self.svn_url_file)
            assert os.path.isfile(self.uuid_file)
            assert os.path.isfile(self.last_revision_handled_file)
        else:
            self.repo = hg.repository(self.ui, repo_path, create=True)
            os.makedirs(os.path.dirname(self.uuid_file))
            f = open(self.revmap_file, 'w')
            f.write('%s\n' % our_util.REVMAP_FILE_VERSION)
            f.flush()
            f.close()

    def clear_current_info(self):
        '''Clear the info relevant to a replayed revision so that the next
        revision can be replayed.
        '''
        # Map files to raw svn data (symlink prefix is preserved)
        self.current_files = {}
        self.deleted_files = {}
        self.current_rev = None
        self.current_files_exec = {}
        self.current_files_symlink = {}
        self.dir_batons = {}
        # Map fully qualified destination file paths to module source path
        self.copies = {}
        self.missing_plaintexts = set()
        self.commit_branches_empty = {}
        self.base_revision = None
        self.branches_to_delete = set()
        self.externals = {}

    def _save_metadata(self):
        '''Save the Subversion metadata. This should really be called after
        every revision is created.
        '''
        pickle_atomic(self.branches, self.branch_info_file, self.meta_data_dir)
        pickle_atomic(self.tags, self.tag_info_file, self.meta_data_dir)

    def branches_in_paths(self, paths):
        '''Given a list of paths, return mapping of all branches touched
        to their branch path.
        '''
        branches = {}
        for p in paths:
            relpath, branch, branchpath = self._split_branch_path(p)
            if relpath is not None:
                branches[branch] = branchpath
        return branches

    def _path_and_branch_for_path(self, path):
        return self._split_branch_path(path)[:2]

    def _split_branch_path(self, path):
        """Figure out which branch inside our repo this path represents, and
        also figure out which path inside that branch it is.

        Raises an exception if it can't perform its job.
        """
        path = self._normalize_path(path)
        if path.startswith('trunk'):
            p = path[len('trunk'):]
            if p and p[0] == '/':
                p = p[1:]
            return p, None, 'trunk'
        elif path.startswith('branches/'):
            p = path[len('branches/'):]
            br = p.split('/')[0]
            if br:
                p = p[len(br)+1:]
                if p and p[0] == '/':
                    p = p[1:]
                return p, br, 'branches/' + br
        return None, None, None

    def set_current_rev(self, rev):
        """Set the revision we're currently converting.
        """
        self.current_rev = rev

    def set_file(self, path, data, isexec=False, islink=False):
        if islink:
            data = 'link ' + data
        self.current_files[path] = data
        self.current_files_exec[path] = isexec
        self.current_files_symlink[path] = islink
        if path in self.deleted_files:
            del self.deleted_files[path]

    def delete_file(self, path):
        self.deleted_files[path] = True
        self.current_files[path] = ''
        self.current_files_exec[path] = False
        self.current_files_symlink[path] = False
        self.ui.status('D %s\n' % path)

    def _normalize_path(self, path):
        '''Normalize a path to strip of leading slashes and our subdir if we
        have one.
        '''
        if path and path[0] == '/':
            path = path[1:]
        if path and path.startswith(self.subdir):
            path = path[len(self.subdir):]
        if path and path[0] == '/':
            path = path[1:]
        return path
        
    def _is_file_included(self, subpath):
        def checkpathinmap(path, mapping):
            def rpairs(name):
                yield '.', name
                e = len(name)
                while e != -1:
                    yield name[:e], name[e+1:]
                    e = name.rfind('/', 0, e)
            
            for pre, suf in rpairs(path):
                try:
                    return mapping[pre]
                except KeyError, err:
                    pass
            return None
        
        if len(self.includepaths) and len(subpath):
            inc = checkpathinmap(subpath, self.includepaths)
        else:
            inc = subpath
        if len(self.excludepaths) and len(subpath):
            exc = checkpathinmap(subpath, self.excludepaths)
        else:
            exc = None
        if inc is None or exc is not None:
            return False
        return True

    def _is_path_valid(self, path):
        subpath = self._split_branch_path(path)[0]
        if subpath is None:
            return False
        return self._is_file_included(subpath)
        

    def _is_path_tag(self, path):
        """If path represents the path to a tag, returns the tag name.

        Otherwise, returns False.
        """
        path = self._normalize_path(path)
        for tags_path in self.tag_locations:
            if path and (path.startswith(tags_path) and
                         len(path) > len('%s/' % tags_path)):
                return path[len(tags_path)+1:].split('/')[0]
        return False

    def get_parent_svn_branch_and_rev(self, number, branch):
        number -= 1
        if (number, branch) in self.revmap:
            return number, branch
        real_num = 0
        for num, br in self.revmap.iterkeys():
            if br != branch:
                continue
            if num <= number and num > real_num:
                real_num = num
        if branch in self.branches:
            parent_branch = self.branches[branch][0]
            parent_branch_rev = self.branches[branch][1]
            # check to see if this branch already existed and is the same
            if parent_branch_rev < real_num:
                return real_num, branch
            # if that wasn't true, then this is the a new branch with the
            # same name as some old deleted branch
            if parent_branch_rev <= 0 and real_num == 0:
                return None, None
            branch_created_rev = self.branches[branch][2]
            if parent_branch == 'trunk':
                parent_branch = None
            if branch_created_rev <= number+1 and branch != parent_branch:
                return self.get_parent_svn_branch_and_rev(
                                                parent_branch_rev+1,
                                                parent_branch)
        if real_num != 0:
            return real_num, branch
        return None, None

    def get_parent_revision(self, number, branch):
        '''Get the parent revision hash for a commit on a specific branch.
        '''
        r, br = self.get_parent_svn_branch_and_rev(number, branch)
        if r is not None:
            return self.revmap[r, br]
        return revlog.nullid

    def update_branch_tag_map_for_rev(self, revision):
        paths = revision.paths
        added_branches = {}
        added_tags = {}
        self.branches_to_delete = set()
        tags_to_delete = set()
        for p in sorted(paths):
            fi, br = self._path_and_branch_for_path(p)
            if fi is not None:
                if fi == '' and paths[p].action != 'D':
                    src_p = paths[p].copyfrom_path
                    src_rev = paths[p].copyfrom_rev
                    src_tag = self._is_path_tag(src_p)

                    if not ((src_p and self._is_path_valid(src_p)) or
                            (src_tag and src_tag in self.tags)):
                        # The branch starts here and is not a copy
                        src_branch = None
                        src_rev = 0
                    elif src_tag:
                        # this is a branch created from a tag. Note that this
                        # really does happen (see Django)
                        src_branch, src_rev = self.tags[src_tag]
                    else:
                        # Not from a tag, and from a valid repo path
                        (src_p,
                        src_branch) = self._path_and_branch_for_path(src_p)
                        if src_p is None:
                            continue
                    if (br not in self.branches or
                        not (src_rev == 0 and src_branch == None)):
                        added_branches[br] = src_branch, src_rev, revision.revnum
                elif fi == '' and br in self.branches:
                    self.branches_to_delete.add(br)
            else:
                t_name = self._is_path_tag(p)
                if t_name == False:
                    continue
                src_p, src_rev = paths[p].copyfrom_path, paths[p].copyfrom_rev
                # if you commit to a tag, I'm calling you stupid and ignoring
                # you.
                if src_p is not None and src_rev is not None:
                    file, branch = self._path_and_branch_for_path(src_p)
                    if file is None:
                        # some crazy people make tags from other tags
                        file = ''
                        from_tag = self._is_path_tag(src_p)
                        if not from_tag:
                            continue
                        branch, src_rev = self.tags[from_tag]
                    if t_name not in added_tags:
                        added_tags[t_name] = branch, src_rev
                    elif file and src_rev > added_tags[t_name][1]:
                        added_tags[t_name] = branch, src_rev
                elif (paths[p].action == 'D' and p.endswith(t_name)
                      and t_name in self.tags):
                        tags_to_delete.add(t_name)
        for t in tags_to_delete:
            del self.tags[t]
        for br in self.branches_to_delete:
            del self.branches[br]
        for t, info in added_tags.items():
            self.ui.status('Tagged %s@%s as %s\n' %
                           (info[0] or 'trunk', info[1], t))
        self.tags.update(added_tags)
        self.branches.update(added_branches)
        self._save_metadata()

    def _updateexternals(self):
        if not self.externals:
            return
        # Accumulate externals records for all branches
        revnum = self.current_rev.revnum
        branches = {}
        for path, entry in self.externals.iteritems():
            if not self._is_path_valid(path):
                continue
            p, b, bp = self._split_branch_path(path)
            if bp not in branches:
                external = svnexternals.externalsfile()
                parent = self.get_parent_revision(revnum, b)
                pctx = self.repo[parent]
                if '.hgsvnexternals' in pctx:
                    external.read(pctx['.hgsvnexternals'].data())
                branches[bp] = external
            else:
                external = branches[bp]
            external[p] = entry

        # Register the file changes
        for bp, external in branches.iteritems():
            path = bp + '/.hgsvnexternals'
            if external:
                self.current_files[path] = external.write()
                self.current_files_symlink[path] = False
                self.current_files_exec[path] = False
            else:
                self.delete_file(path)

    def commit_current_delta(self):
        if hasattr(self, '_exception_info'):  #pragma: no cover
            traceback.print_exception(*self._exception_info)
            raise ReplayException()
        if self.missing_plaintexts:
            raise MissingPlainTextError()
        self._updateexternals()
        files_to_commit = self.current_files.keys()
        files_to_commit.extend(self.current_files_symlink.keys())
        files_to_commit.extend(self.current_files_exec.keys())
        files_to_commit = sorted(set(files_to_commit))
        branch_batches = {}
        rev = self.current_rev
        date = rev.date.replace('T', ' ').replace('Z', '').split('.')[0]
        date += ' -0000'

        # build up the branches that have files on them
        for f in files_to_commit:
            if not  self._is_path_valid(f):
                continue
            p, b = self._path_and_branch_for_path(f)
            if b not in branch_batches:
                branch_batches[b] = []
            branch_batches[b].append((p, f))
        # close any branches that need it
        closed_revs = set()
        for branch in self.branches_to_delete:
            closed = revlog.nullid
            if 'closed-branches' in self.repo.branchtags():
                closed = self.repo['closed-branches'].node()
            branchedits = sorted(filter(lambda x: x[0][1] == branch and x[0][0] < rev.revnum,
                                        self.revmap.iteritems()), reverse=True)
            if len(branchedits) < 1:
                # can't close a branch that never existed
                continue
            ha = branchedits[0][1]
            closed_revs.add(ha)
            # self.get_parent_revision(rev.revnum, branch)
            parentctx = self.repo.changectx(ha)
            parents = (ha, closed)
            def del_all_files(*args):
                raise IOError
            files = parentctx.manifest().keys()
            current_ctx = context.memctx(self.repo,
                                         parents,
                                         rev.message or ' ',
                                         files,
                                         del_all_files,
                                         self.authorforsvnauthor(rev.author),
                                         date,
                                         {'branch': 'closed-branches'})
            new_hash = self.repo.commitctx(current_ctx)
            self.ui.status('Marked branch %s as closed.\n' % (branch or
                                                              'default'))
        for branch, files in branch_batches.iteritems():
            if branch in self.commit_branches_empty and files:
                del self.commit_branches_empty[branch]
            files = dict(files)

            parents = (self.get_parent_revision(rev.revnum, branch),
                       revlog.nullid)
            if parents[0] in closed_revs and branch in self.branches_to_delete:
                continue
            # TODO this needs to be fixed with the new revmap
            extra = our_util.build_extra(rev.revnum, branch,
                                         open(self.uuid_file).read(),
                                         self.subdir)
            if branch is not None:
                if (branch not in self.branches
                    and branch not in self.repo.branchtags()):
                    continue
            parent_ctx = self.repo.changectx(parents[0])
            if '.hgsvnexternals' not in parent_ctx and '.hgsvnexternals' in files:
                # Do not register empty externals files
                if not self.current_files[files['.hgsvnexternals']]:
                    del files['.hgsvnexternals']

            def filectxfn(repo, memctx, path):
                current_file = files[path]
                if current_file in self.deleted_files:
                    raise IOError()
                copied = self.copies.get(current_file)
                flags = parent_ctx.flags(path)
                is_exec = self.current_files_exec.get(current_file, 'x' in flags)
                is_link = self.current_files_symlink.get(current_file, 'l' in flags)
                if current_file in self.current_files:
                    data = self.current_files[current_file]
                    if is_link:
                        assert data.startswith('link ')
                        data = data[len('link '):]
                else:
                    data = parent_ctx.filectx(path).data()
                return context.memfilectx(path=path,
                                          data=data,
                                          islink=is_link, isexec=is_exec,
                                          copied=copied)
            current_ctx = context.memctx(self.repo,
                                         parents,
                                         rev.message or '...',
                                         files.keys(),
                                         filectxfn,
                                         self.authorforsvnauthor(rev.author),
                                         date,
                                         extra)
            new_hash = self.repo.commitctx(current_ctx)
            self.ui.status('committed as %s on branch %s\n' %
                           (node.hex(new_hash), (branch or 'default')))
            if (rev.revnum, branch) not in self.revmap:
                self.add_to_revmap(rev.revnum, branch, new_hash)
        # now we handle branches that need to be committed without any files
        for branch in self.commit_branches_empty:
            ha = self.get_parent_revision(rev.revnum, branch)
            if ha == node.nullid:
                continue
            parent_ctx = self.repo.changectx(ha)
            def del_all_files(*args):
                raise IOError
           # True here meant nuke all files, shouldn't happen with branch closing
            if self.commit_branches_empty[branch]: #pragma: no cover
               assert False, 'Got asked to commit non-closed branch as empty with no files. Please report this issue.'
            extra = our_util.build_extra(rev.revnum, branch,
                                     open(self.uuid_file).read(),
                                     self.subdir)
            current_ctx = context.memctx(self.repo,
                                         (ha, node.nullid),
                                         rev.message or ' ',
                                         [],
                                         del_all_files,
                                         self.authorforsvnauthor(rev.author),
                                         date,
                                         extra)
            new_hash = self.repo.commitctx(current_ctx)
            self.ui.status('committed as %s on branch %s\n' %
                           (node.hex(new_hash), (branch or 'default')))
            if (rev.revnum, branch) not in self.revmap:
                self.add_to_revmap(rev.revnum, branch, new_hash)
        self.clear_current_info()

    def authorforsvnauthor(self, author):
        if(author in self.authors):
            return self.authors[author]
        return '%s%s' %(author, self.author_host)

    def readauthors(self, authorfile):
        self.ui.status(
            ('Reading authormap %s\n')
            % authorfile)
        f = open(authorfile, 'r')
        for line in f:
            if not line.strip():
                continue
            try:
                srcauth, dstauth = line.split('=', 1)
                srcauth = srcauth.strip()
                dstauth = dstauth.strip()
                if srcauth in self.authors and dstauth != self.authors[srcauth]:
                    self.ui.status(
                        ('Overriding mapping for author %s, was %s, now %s\n')
                        % (srcauth, self.authors[srcauth], dstauth))
                else:
                    self.ui.debug(('Mapping author %s to %s\n')
                        % (srcauth, dstauth))
                    self.authors[srcauth] = dstauth
            except IndexError:
                self.ui.warn(
                    ('Ignoring bad line in author map file %s: %s\n')
                    % (authorfile, line.rstrip()))
        f.close()

    def writeauthors(self):
        f = open(self.authors_file, 'w+')
        self.ui.status(
            ('Writing author map file %s\n')
            % self.authors_file)
        for author in self.authors:
            f.write("%s=%s\n" % (author, self.authors[author]))
        f.close()

    def readfilemap(self, filemapfile):
        self.ui.status(
            ('Reading filemap %s\n')
            % filemapfile)
        def addpathtomap(path, mapping, mapname):
            if path in mapping:
                self.ui.warn(
                    ('%d alreading in %s list\n')
                    % (path, mapname))
            else:
                mapping[path] = path
        
        f = open(filemapfile, 'r')
        for line in f:
            if line.strip() == '':
                continue
            try:
                cmd, path = line.split(' ', 1)
                cmd = cmd.strip()
                path = path.strip()
                if cmd == 'include':
                    addpathtomap(path, self.includepaths, 'include')
                elif cmd == 'exclude':
                    addpathtomap(path, self.excludepaths, 'exclude')
                else:
                    self.ui.warn(
                        ('Unknown filemap command %s\n')
                        % cmd)
            except IndexError:
                self.ui.warn(
                    ('Ignoring bad line in filemap %s: %s\n')
                    % (filemapfile, line.rstrip()))
        f.close()

    @property
    def meta_data_dir(self):
        return os.path.join(self.path, '.hg', 'svn')

    def meta_file_named(self, name):
        return os.path.join(self.meta_data_dir, name)

    @property
    def revmap_file(self):
        return self.meta_file_named('rev_map')

    @property
    def svn_url_file(self):
        return self.meta_file_named('url')

    @property
    def uuid_file(self):
        return self.meta_file_named('uuid')

    @property
    def last_revision_handled_file(self):
        return self.meta_file_named('last_rev')

    @property
    def branch_info_file(self):
        return self.meta_file_named('branch_info')

    @property
    def tag_info_file(self):
        return self.meta_file_named('tag_info')

    @property
    def tag_locations_file(self):
        return self.meta_file_named('tag_locations')

    @property
    def url(self):
        return open(self.svn_url_file).read()

    @property
    def authors_file(self):
        return self.meta_file_named('authors')

    @stash_exception_on_self
    def delete_entry(self, path, revision_bogus, parent_baton, pool=None):
        br_path, branch = self._path_and_branch_for_path(path)
        if br_path == '':
            self.branches_to_delete.add(branch)
        if br_path is not None:
            ha = self.get_parent_revision(self.current_rev.revnum, branch)
            if ha == revlog.nullid:
                return
            ctx = self.repo.changectx(ha)
            if br_path not in ctx:
                br_path2 = ''
                if br_path != '':
                    br_path2 = br_path + '/'
                # assuming it is a directory
                self.externals[path] = None
                def delete_x(x):
                    self.deleted_files[x] = True
                map(delete_x, [pat for pat in self.current_files.iterkeys()
                               if pat.startswith(path)])
                for f in ctx.walk(our_util.PrefixMatch(br_path2)):
                    f_p = '%s/%s' % (path, f[len(br_path2):])
                    if f_p not in self.current_files:
                        self.delete_file(f_p)
            self.delete_file(path)

    @stash_exception_on_self
    def open_file(self, path, parent_baton, base_revision, p=None):
        self.current_file = 'foobaz'
        fpath, branch = self._path_and_branch_for_path(path)
        if fpath:
            self.current_file = path
            self.ui.status('M %s\n' % path)
            if base_revision != -1:
                self.base_revision = base_revision
            else:
                self.base_revision = None
            self.should_edit_most_recent_plaintext = True

    def aresamefiles(self, parentctx, childctx, files):
        """Assuming all files exist in childctx and parentctx, return True
        if none of them was changed in-between.
        """
        if parentctx == childctx:
            return True
        if parentctx.rev() > childctx.rev():
            parentctx, childctx = childctx, parentctx

        def selfandancestors(selfctx):
            yield selfctx
            for ctx in selfctx.ancestors():
                yield ctx

        files = dict.fromkeys(files)
        for pctx in selfandancestors(childctx):
            if pctx.rev() <= parentctx.rev():
                return True
            for f in pctx.files():
                if f in files:
                    return False
        # parentctx is not an ancestor of childctx, files are unrelated
        return False

    @stash_exception_on_self
    def add_file(self, path, parent_baton, copyfrom_path,
                 copyfrom_revision, file_pool=None):
        self.current_file = 'foobaz'
        self.base_revision = None
        if path in self.deleted_files:
            del self.deleted_files[path]
        fpath, branch = self._path_and_branch_for_path(path)
        if not fpath:
            return
        self.current_file = path
        self.should_edit_most_recent_plaintext = False
        if not copyfrom_path:
            self.ui.status('A %s\n' % path)
            return
        self.ui.status('A+ %s\n' % path)
        (from_file,
         from_branch) = self._path_and_branch_for_path(copyfrom_path)
        if not from_file:
            self.missing_plaintexts.add(path)
            return
        ha = self.get_parent_revision(copyfrom_revision + 1,
                                      from_branch)
        ctx = self.repo.changectx(ha)
        if from_file in ctx:
            fctx = ctx.filectx(from_file)
            flags = fctx.flags()
            cur_file = self.current_file
            self.set_file(cur_file, fctx.data(), 'x' in flags, 'l' in flags)
        if from_branch == branch:
            parentid = self.get_parent_revision(self.current_rev.revnum,
                                                branch)
            if parentid != revlog.nullid:
                parentctx = self.repo.changectx(parentid)
                if self.aresamefiles(parentctx, ctx, [from_file]):
                    self.copies[path] = from_file

    @stash_exception_on_self
    def add_directory(self, path, parent_baton, copyfrom_path,
                      copyfrom_revision, dir_pool=None):
        self.dir_batons[path] = path
        br_path, branch = self._path_and_branch_for_path(path)
        if br_path is not None:
            if not copyfrom_path and not br_path:
                self.commit_branches_empty[branch] = True
            else:
                self.commit_branches_empty[branch] = False
        if br_path is None or not copyfrom_path:
            return path
        if copyfrom_path:
            tag = self._is_path_tag(copyfrom_path)
            if tag not in self.tags:
                tag = None
            if not self._is_path_valid(copyfrom_path) and not tag:
                self.missing_plaintexts.add('%s/' % path)
                return path

        if tag:
            source_branch, source_rev = self.tags[tag]
            cp_f = ''
        else:
            source_rev = copyfrom_revision
            cp_f, source_branch = self._path_and_branch_for_path(copyfrom_path)
        new_hash = self.get_parent_revision(source_rev + 1,
                                            source_branch)
        if new_hash == node.nullid:
            self.missing_plaintexts.add('%s/' % path)
            return path
        cp_f_ctx = self.repo.changectx(new_hash)
        if cp_f != '/' and cp_f != '':
            cp_f = '%s/' % cp_f
        else:
            cp_f = ''
        copies = {}
        for f in cp_f_ctx:
            if not f.startswith(cp_f):
                continue
            f2 = f[len(cp_f):]
            fctx = cp_f_ctx.filectx(f)
            fp_c = path + '/' + f2
            self.set_file(fp_c, fctx.data(), 'x' in fctx.flags(), 'l' in fctx.flags())
            if fp_c in self.deleted_files:
                del self.deleted_files[fp_c]
            if branch == source_branch:
                copies[fp_c] = f
        if copies:
            # Preserve the directory copy records if no file was changed between
            # the source and destination revisions, or discard it completely.
            parentid = self.get_parent_revision(self.current_rev.revnum, branch)
            if parentid != revlog.nullid:
                parentctx = self.repo.changectx(parentid)
                if self.aresamefiles(parentctx, cp_f_ctx, copies.values()):
                    self.copies.update(copies)
        return path

    @stash_exception_on_self
    def change_file_prop(self, file_baton, name, value, pool=None):
        if name == 'svn:executable':
            self.current_files_exec[self.current_file] = bool(value is not None)
        elif name == 'svn:special':
            self.current_files_symlink[self.current_file] = bool(value is not None)

    @stash_exception_on_self
    def change_dir_prop(self, dir_baton, name, value, pool=None):
        if dir_baton is None:
            return
        path = self.dir_batons[dir_baton]
        if name == 'svn:externals':
            self.externals[path] = value

    @stash_exception_on_self
    def open_directory(self, path, parent_baton, base_revision, dir_pool=None):
        self.dir_batons[path] = path
        p_, branch = self._path_and_branch_for_path(path)
        if p_ == '':
            self.commit_branches_empty[branch] = False
        return path

    @stash_exception_on_self
    def close_directory(self, dir_baton, dir_pool=None):
        if dir_baton is not None:
            del self.dir_batons[dir_baton]

    @stash_exception_on_self
    def apply_textdelta(self, file_baton, base_checksum, pool=None):
        base = ''
        if not self._is_path_valid(self.current_file):
            return lambda x: None
        if (self.current_file in self.current_files
            and not self.should_edit_most_recent_plaintext):
            base = self.current_files[self.current_file]
        elif (base_checksum is not None or
              self.should_edit_most_recent_plaintext):
                p_, br = self._path_and_branch_for_path(self.current_file)
                par_rev = self.current_rev.revnum
                if self.base_revision:
                    par_rev = self.base_revision + 1
                ha = self.get_parent_revision(par_rev, br)
                if ha != revlog.nullid:
                    ctx = self.repo.changectx(ha)
                    if not p_ in ctx:
                        self.missing_plaintexts.add(self.current_file)
                        # short circuit exit since we can't do anything anyway
                        return lambda x: None
                    fctx = ctx[p_]
                    base = fctx.data()
                    if 'l' in fctx.flags():
                        base = 'link ' + base
        source = cStringIO.StringIO(base)
        target = cStringIO.StringIO()
        self.stream = target

        handler, baton = delta.svn_txdelta_apply(source, target, None)
        if not callable(handler): #pragma: no cover
            # TODO(augie) Raise a real exception, don't just fail an assertion.
            assert False, 'handler not callable, bindings are broken'
        def txdelt_window(window):
            try:
                if not self._is_path_valid(self.current_file):
                    return
                handler(window, baton)
                # window being None means commit this file
                if not window:
                    self.current_files[self.current_file] = target.getvalue()
            except core.SubversionException, e: #pragma: no cover
                if e.message == 'Delta source ended unexpectedly':
                    self.missing_plaintexts.add(self.current_file)
                else: #pragma: no cover
                    self._exception_info = sys.exc_info()
                    raise
            except: #pragma: no cover
                print len(base), self.current_file
                self._exception_info = sys.exc_info()
                raise
        return txdelt_window

class MissingPlainTextError(Exception):
    """Exception raised when the repo lacks a source file required for replaying
    a txdelta.
    """

class ReplayException(Exception):
    """Exception raised when you try and commit but the replay encountered an
    exception.
    """