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scripts/python/TerraSync/terrasync/dirindex.py

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+# -*- coding: utf-8 -*-
+
+# dirindex.py --- Class used to parse .dirindex files
+#
+# Copyright (C) 2016  Torsten Dreyer
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+"""Parser for .dirindex files."""
+
+from .exceptions import InvalidDirIndexFile
+from .virtual_path import VirtualPath
+
+
+class DirIndex:
+    """Parser for .dirindex files."""
+
+    def __init__(self, dirIndexFile):
+        self.directories = []
+        self.files = []
+        self.tarballs = []
+        self.version = 0
+        self.path = None        # will be a VirtualPath instance when set
+
+        # readFrom() stores the raw contents of the .dirindex file in this
+        # attribute. This is useful for troubleshooting.
+        self._rawContents = None
+
+        with open(dirIndexFile, "r", encoding="ascii") as f:
+            self.readFrom(f)
+
+        self._sanityCheck()
+
+    @classmethod
+    def checkForBackslashOrLeadingSlash(cls, line, path):
+        if '\\' in path or path.startswith('/'):
+            raise InvalidDirIndexFile(
+                r"invalid '\' or leading '/' in path field from line {!r}"
+                .format(line))
+
+    @classmethod
+    def checkForSlashBackslashOrDoubleColon(cls, line, name):
+        if '/' in name or '\\' in name:
+            raise InvalidDirIndexFile(
+                r"invalid '\' or '/' in name field from line {!r}"
+                .format(line))
+
+        if name == "..":
+            raise InvalidDirIndexFile(
+                r"invalid name field equal to '..' in line {!r}".format(line))
+
+    def readFrom(self, readable):
+        self._rawContents = readable.read()
+
+        for line in self._rawContents.split('\n'):
+            line = line.strip()
+            if line.startswith('#'):
+                continue
+
+            tokens = line.split(':')
+            if len(tokens) == 0:
+                continue
+            elif tokens[0] == "version":
+                self.version = int(tokens[1])
+            elif tokens[0] == "path":
+                self.checkForBackslashOrLeadingSlash(line, tokens[1])
+                # This is relative to the repository root
+                self.path = VirtualPath(tokens[1])
+
+                if ".." in self.path.parts:
+                    raise InvalidDirIndexFile(
+                        "'..' component found in 'path' entry {!r}"
+                        .format(self.path))
+            elif tokens[0] == "d":
+                self.checkForSlashBackslashOrDoubleColon(line, tokens[1])
+                self.directories.append({'name': tokens[1], 'hash': tokens[2]})
+            elif tokens[0] == "f":
+                self.checkForSlashBackslashOrDoubleColon(line, tokens[1])
+                self.files.append({'name': tokens[1],
+                                   'hash': tokens[2], 'size': int(tokens[3])})
+            elif tokens[0] == "t":
+                self.checkForSlashBackslashOrDoubleColon(line, tokens[1])
+                self.tarballs.append({'name': tokens[1], 'hash': tokens[2],
+                                      'size': int(tokens[3])})
+
+    def _sanityCheck(self):
+        if self.path is None:
+            assert self._rawContents is not None
+
+            firstLines = self._rawContents.split('\n')[:5]
+            raise InvalidDirIndexFile(
+                "no 'path' field found; the first lines of this .dirindex file "
+                "follow:\n\n" + '\n'.join(firstLines))