[meld] vc.darcs: New VC module supporting newest darcs

[Kai Willadsen <kaiw src gnome org>]

commit 12663886ecf91b4c965bad39999b21e2b717e07e
Author: Guillaume Hoffmann <guillaumh gmail com>
Date:   Tue Mar 15 07:19:57 2016 +1000

    vc.darcs: New VC module supporting newest darcs

 meld/vc/darcs.py |  174 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 174 insertions(+), 0 deletions(-)
---
diff --git a/meld/vc/darcs.py b/meld/vc/darcs.py
new file mode 100644
index 0000000..d4d307b
--- /dev/null
+++ b/meld/vc/darcs.py
@@ -0,0 +1,174 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 2010-2015 Kai Willadsen <kai willadsen gmail com>
+# Copyright (C)      2016 Guillaume Hoffmann <guillaumh gmail com>
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import errno
+import os
+import re
+import shutil
+import stat
+import subprocess
+import sys
+import tempfile
+from collections import defaultdict
+from . import _vc
+
+class Vc(_vc.Vc):
+
+# Requires Darcs version >= 2.10.3
+# TODO implement get_commits_to_push_summary using `darcs push --dry-run`
+# Currently `darcs whatsnew` (as of v2.10.3) does not report conflicts
+# see http://bugs.darcs.net/issue2138
+
+    CMD = "darcs"
+    NAME = "Darcs"
+    VC_DIR = "_darcs"
+
+    state_map = {
+        "a": _vc.STATE_NONE,
+        "A": _vc.STATE_NEW,
+        "M": _vc.STATE_MODIFIED,
+        "M!": _vc.STATE_CONFLICT,
+        "R": _vc.STATE_REMOVED,
+        "F": _vc.STATE_NONEXIST,  # previous name of file
+        "T": _vc.STATE_RENAMED,   # new name of file
+    }
+
+    @classmethod
+    def is_installed(cls):
+        try:
+            proc = _vc.popen([cls.CMD, '--version'])
+            # check that version >= 2.10.3
+            (x,y,z) = proc.read().split(" ", 1)[0].split(".", 2)[:3]
+            assert (x,y,z) >= (2,10,3)
+            return True
+        except Exception:
+            return False
+
+    def commit(self, runner, files, message):
+        command = [self.CMD, 'record', '-a', '-m', message]
+        runner(command, [], refresh=True, working_dir=self.root)
+
+    def update(self, runner):
+        command = [self.CMD, 'pull', '-a']
+        runner(command, [], refresh=True, working_dir=self.root)
+
+    def push(self, runner):
+        command = [self.CMD, 'push', '-a']
+        runner(command, [], refresh=True, working_dir=self.root)
+
+    def add(self, runner, files):
+        command = [self.CMD, 'add', '-r']
+        runner(command, files, refresh=True, working_dir=self.root)
+
+    def remove(self, runner, files):
+        command = [self.CMD, 'remove', '-r']
+        runner(command, files, refresh=True, working_dir=self.root)
+
+    def revert(self, runner, files):
+        command = [self.CMD, 'revert', '-a']
+        runner(command, files, refresh=True, working_dir=self.root)
+
+    def get_path_for_repo_file(self, path, commit=None):
+        if commit is not None:
+            raise NotImplementedError()
+
+        if not path.startswith(self.root + os.path.sep):
+            raise _vc.InvalidVCPath(self, path, "Path not in repository")
+
+        # `darcs show contents` needs the path before rename
+        if path in self._reverse_rename_cache:
+            path = self._reverse_rename_cache[path]
+
+        path = path[len(self.root) + 1:]
+        process = subprocess.Popen([self.CMD, "show", "contents", path], cwd=self.root,
+                                   stdout=subprocess.PIPE,
+                                   stderr=subprocess.PIPE)
+
+        with tempfile.NamedTemporaryFile(prefix='meld-tmp', delete=False) as f:
+            shutil.copyfileobj(process.stdout, f)
+        return f.name
+
+    @classmethod
+    def valid_repo(cls, path):
+        return not _vc.call([cls.CMD, "show", "repo", "--no-files"], cwd=path)
+
+    def _update_tree_state_cache(self, path):
+        # FIXME: currently ignoring 'path' due to darcs's bad
+        #        behaviour (= fails) when given "" argument
+        """ Update the state of the file(s) at self._tree_cache['path'] """
+        while 1:
+            try:
+                proc = _vc.popen([self.CMD, "whatsnew" , "-sl", "--machine-readable"],
+                                 cwd=self.location)
+                lines = proc.read().split("\n")[:-1]
+                break
+            except OSError as e:
+                if e.errno != errno.EAGAIN:
+                    raise
+
+        # Files can appear twice in the list if were modified and renamed
+        # at once. Darcs first show file moves then modifications.
+        if len(lines) == 0 and os.path.isfile(path):
+            # If we're just updating a single file there's a chance that it
+            # was it was previously modified, and now has been edited so that
+            # it is un-modified.  This will result in an empty 'entries' list,
+            # and self._tree_cache['path'] will still contain stale data.
+            # When this corner case occurs we force self._tree_cache['path']
+            # to STATE_NORMAL.
+            self._tree_cache[path] = _vc.STATE_NORMAL
+        else:
+            tree_cache = defaultdict(int)
+            tree_meta_cache = defaultdict(list)
+            self._rename_cache = rename_cache = {}
+            self._reverse_rename_cache = {}
+            old_name = None
+            for line in lines:
+                # skip empty lines and line starting with "What's new in foo"
+                if (not line.strip()) or line.startswith("What"):
+                    continue
+                statekey, name = line.split(" ", 1)
+                name = os.path.normpath(name)
+                if statekey == "F":
+                    old_name = name
+
+                path = os.path.join(self.location, name)
+
+                if statekey == "T" and old_name:
+                    old_path = os.path.join(self.location, old_name)
+                    rename_cache[old_path] = path
+                    old_name = None
+
+                state = self.state_map.get(statekey.strip(), _vc.STATE_NONE)
+                tree_cache[path] = state
+
+            for old, new in rename_cache.items():
+                self._reverse_rename_cache[new] = old
+                old_name = old[len(self.root) + 1:]
+                new_name = new[len(self.root) + 1:]
+                tree_meta_cache[new] = ("%s ➡ %s" % (old_name, new_name))
+
+            self._tree_cache.update(
+                dict((x, y) for x, y in tree_cache.items()))
+            self._tree_meta_cache = dict(tree_meta_cache)
+