zip archives: keep individual files compression type

While hardcoding the compression to zipfile.ZIP_DEFLATED works for
most use cases of mat, being able to produce cleaned up uncompressed
zip files is useful for content that cannot be compressed more.

In addition it also enables to use mat2 for reproducible builds of
Android bootanimation files file that don't support compression.

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>

libmat2/archive.py

@@ -120,6 +120,18 @@ class ArchiveBasedAbstractParser(abstract.AbstractParser):
         # pylint: disable=unused-argument
         return member
 
+    @staticmethod
+    def _get_member_compression(member: ArchiveMember):
+        """Get the compression of the archive member."""
+        # pylint: disable=unused-argument
+        return None
+
+    @staticmethod
+    def _set_member_compression(member: ArchiveMember, compression) -> ArchiveMember:
+        """Set the compression of the archive member."""
+        # pylint: disable=unused-argument
+        return member
+
     def get_meta(self) -> Dict[str, Union[str, dict]]:
         meta = dict()  # type: Dict[str, Union[str, dict]]
 
@@ -184,6 +196,8 @@ class ArchiveBasedAbstractParser(abstract.AbstractParser):
                 original_permissions = os.stat(full_path).st_mode
                 os.chmod(full_path, original_permissions | stat.S_IWUSR | stat.S_IRUSR)
 
+                original_compression = self._get_member_compression(item)
+
                 if self._specific_cleanup(full_path) is False:
                     logging.warning("Something went wrong during deep cleaning of %s",
                                     member_name)
@@ -223,6 +237,7 @@ class ArchiveBasedAbstractParser(abstract.AbstractParser):
 
                 zinfo = self.member_class(member_name)  # type: ignore
                 zinfo = self._set_member_permissions(zinfo, original_permissions)
+                zinfo = self._set_member_compression(zinfo, original_compression)
                 clean_zinfo = self._clean_member(zinfo)
                 self._add_file_to_archive(zout, clean_zinfo, full_path)
 
@@ -368,7 +383,6 @@ class ZipParser(ArchiveBasedAbstractParser):
         super().__init__(filename)
         self.archive_class = zipfile.ZipFile
         self.member_class = zipfile.ZipInfo
-        self.zip_compression_type = zipfile.ZIP_DEFLATED
 
     def is_archive_valid(self):
         try:
@@ -410,7 +424,7 @@ class ZipParser(ArchiveBasedAbstractParser):
         assert isinstance(member, zipfile.ZipInfo)  # please mypy
         with open(full_path, 'rb') as f:
             archive.writestr(member, f.read(),
-                             compress_type=self.zip_compression_type)
+                             compress_type=member.compress_type)
 
     @staticmethod
     def _get_all_members(archive: ArchiveClass) -> List[ArchiveMember]:
@@ -421,3 +435,12 @@ class ZipParser(ArchiveBasedAbstractParser):
     def _get_member_name(member: ArchiveMember) -> str:
         assert isinstance(member, zipfile.ZipInfo)  # please mypy
         return member.filename
+
+    @staticmethod
+    def _get_member_compression(member: ArchiveMember):
+        return member.compress_type
+
+    @staticmethod
+    def _set_member_compression(member: ArchiveMember, compression) -> ArchiveMember:
+        member.compress_type = compression
+        return member

tests/test_libmat2.py

@@ -175,14 +175,30 @@ class TestGetMeta(unittest.TestCase):
 
     def test_zip(self):
         with zipfile.ZipFile('./tests/data/dirty.zip', 'w') as zout:
-            zout.write('./tests/data/dirty.flac')
+            zout.write('./tests/data/dirty.flac',
-            zout.write('./tests/data/dirty.docx')
+                       compress_type = zipfile.ZIP_STORED)
-            zout.write('./tests/data/dirty.jpg')
+            zout.write('./tests/data/dirty.docx',
+                       compress_type = zipfile.ZIP_DEFLATED)
+            zout.write('./tests/data/dirty.jpg',
+                       compress_type = zipfile.ZIP_BZIP2)
+            zout.write('./tests/data/dirty.txt',
+                       compress_type = zipfile.ZIP_LZMA)
         p, mimetype = parser_factory.get_parser('./tests/data/dirty.zip')
         self.assertEqual(mimetype, 'application/zip')
         meta = p.get_meta()
         self.assertEqual(meta['tests/data/dirty.flac']['comments'], 'Thank you for using MAT !')
         self.assertEqual(meta['tests/data/dirty.docx']['word/media/image1.png']['Comment'], 'This is a comment, be careful!')
+
+        with zipfile.ZipFile('./tests/data/dirty.zip') as zipin:
+            members = {
+                'tests/data/dirty.flac' : zipfile.ZIP_STORED,
+                'tests/data/dirty.docx': zipfile.ZIP_DEFLATED,
+                'tests/data/dirty.jpg' : zipfile.ZIP_BZIP2,
+                'tests/data/dirty.txt' : zipfile.ZIP_LZMA,
+            }
+            for k, v in members.items():
+                self.assertEqual(zipin.getinfo(k).compress_type, v)
+
         os.remove('./tests/data/dirty.zip')
 
     def test_wmv(self):
@@ -595,9 +611,14 @@ class TestCleaning(unittest.TestCase):
 class TestCleaningArchives(unittest.TestCase):
     def test_zip(self):
         with zipfile.ZipFile('./tests/data/dirty.zip', 'w') as zout:
-            zout.write('./tests/data/dirty.flac')
+            zout.write('./tests/data/dirty.flac',
-            zout.write('./tests/data/dirty.docx')
+                       compress_type = zipfile.ZIP_STORED)
-            zout.write('./tests/data/dirty.jpg')
+            zout.write('./tests/data/dirty.docx',
+                       compress_type = zipfile.ZIP_DEFLATED)
+            zout.write('./tests/data/dirty.jpg',
+                       compress_type = zipfile.ZIP_BZIP2)
+            zout.write('./tests/data/dirty.txt',
+                       compress_type = zipfile.ZIP_LZMA)
         p = archive.ZipParser('./tests/data/dirty.zip')
         meta = p.get_meta()
         self.assertEqual(meta['tests/data/dirty.docx']['word/media/image1.png']['Comment'], 'This is a comment, be careful!')
@@ -609,6 +630,16 @@ class TestCleaningArchives(unittest.TestCase):
         self.assertEqual(p.get_meta(), {})
         self.assertTrue(p.remove_all())
 
+        with zipfile.ZipFile('./tests/data/dirty.zip') as zipin:
+            members = {
+                'tests/data/dirty.flac' : zipfile.ZIP_STORED,
+                'tests/data/dirty.docx': zipfile.ZIP_DEFLATED,
+                'tests/data/dirty.jpg' : zipfile.ZIP_BZIP2,
+                'tests/data/dirty.txt' : zipfile.ZIP_LZMA,
+            }
+            for k, v in members.items():
+                self.assertEqual(zipin.getinfo(k).compress_type, v)
+
         os.remove('./tests/data/dirty.zip')
         os.remove('./tests/data/dirty.cleaned.zip')
         os.remove('./tests/data/dirty.cleaned.cleaned.zip')