1 files changed, 135 insertions, 0 deletions

diff --git a/libmat/parser.py b/libmat/parser.py
new file mode 100644
index 0000000..1765da8
--- /dev/null
+++ b/libmat/parser.py
@@ -0,0 +1,135 @@
+''' Parent class of all parser
+'''
+
+import os
+import shutil
+import tempfile
+
+import hachoir_core
+import hachoir_editor
+
+import mat
+
+NOMETA = frozenset((
+    '.bmp',   # "raw" image
+    '.rdf',   # text
+    '.txt',   # plain text
+    '.xml',   # formated text (XML)
+    '.rels',  # openXML formated text
+))
+
+FIELD = object()
+
+
+class GenericParser(object):
+    ''' Parent class of all parsers
+    '''
+    def __init__(self, filename, parser, mime, backup, is_writable, **kwargs):
+        self.filename = ''
+        self.parser = parser
+        self.mime = mime
+        self.backup = backup
+        self.is_writable = is_writable
+        self.editor = hachoir_editor.createEditor(parser)
+        try:
+            self.filename = hachoir_core.cmd_line.unicodeFilename(filename)
+        except TypeError:  # get rid of "decoding Unicode is not supported"
+            self.filename = filename
+        self.basename = os.path.basename(filename)
+        _, output = tempfile.mkstemp()
+        self.output = hachoir_core.cmd_line.unicodeFilename(output)
+
+    def __del__(self):
+        ''' Remove tempfile if it was not used
+        '''
+        if os.path.exists(self.output):
+            mat.secure_remove(self.output)
+
+    def is_clean(self):
+        '''
+            Check if the file is clean from harmful metadatas
+        '''
+        for field in self.editor:
+            if self._should_remove(field):
+                return self._is_clean(self.editor)
+        return True
+
+    def _is_clean(self, fieldset):
+        for field in fieldset:
+            remove = self._should_remove(field)
+            if remove is True:
+                return False
+            if remove is FIELD:
+                if not self._is_clean(field):
+                    return False
+        return True
+
+    def remove_all(self):
+        ''' Remove all compromising fields
+        '''
+        state = self._remove_all(self.editor)
+        hachoir_core.field.writeIntoFile(self.editor, self.output)
+        self.do_backup()
+        return state
+
+    def _remove_all(self, fieldset):
+        ''' Recursive way to handle tree metadatas
+        '''
+        try:
+            for field in fieldset:
+                remove = self._should_remove(field)
+                if remove is True:
+                    self._remove(fieldset, field.name)
+                if remove is FIELD:
+                    self._remove_all(field)
+            return True
+        except:
+            return False
+
+    def _remove(self, fieldset, field):
+        ''' Delete the given field
+        '''
+        del fieldset[field]
+
+    def get_meta(self):
+        ''' Return a dict with all the meta of the file
+        '''
+        metadata = {}
+        self._get_meta(self.editor, metadata)
+        return metadata
+
+    def _get_meta(self, fieldset, metadata):
+        ''' Recursive way to handle tree metadatas
+        '''
+        for field in fieldset:
+            remove = self._should_remove(field)
+            if remove:
+                try:
+                    metadata[field.name] = field.value
+                except:
+                    metadata[field.name] = 'harmful content'
+            if remove is FIELD:
+                self._get_meta(field, None)
+
+    def _should_remove(self, key):
+        ''' Return True if the field is compromising
+            abstract method
+        '''
+        raise NotImplementedError
+
+    def create_backup_copy(self):
+        ''' Create a backup copy
+        '''
+        shutil.copy2(self.filename, self.filename + '.bak')
+
+    def do_backup(self):
+        ''' Keep a backup of the file if asked.
+
+            The process of double-renaming is not very elegant,
+            but it greatly simplify new strippers implementation.
+        '''
+        if self.backup:
+            shutil.move(self.filename, self.filename + '.bak')
+        else:
+            mat.secure_remove(self.filename)
+        shutil.move(self.output, self.filename)