Merge pull request #2364 from enkore/f/autocomp

Refactor compression decision stuff

src/borg/archive.py

@@ -21,11 +21,11 @@ logger = create_logger()
 from . import xattr
 from .cache import ChunkListEntry
 from .chunker import Chunker
-from .compress import Compressor
+from .compress import Compressor, CompressionSpec
 from .constants import *  # NOQA
 from .hashindex import ChunkIndex, ChunkIndexEntry
 from .helpers import Manifest
-from .helpers import Chunk, ChunkIteratorFileWrapper, open_item
+from .helpers import ChunkIteratorFileWrapper, open_item
 from .helpers import Error, IntegrityError, set_ec
 from .helpers import uid2user, user2uid, gid2group, group2gid
 from .helpers import parse_timestamp, to_localtime
@@ -36,7 +36,6 @@ from .helpers import bin_to_hex
 from .helpers import safe_ns
 from .helpers import ellipsis_truncate, ProgressIndicatorPercent, log_multi
 from .helpers import PathPrefixPattern, FnmatchPattern
-from .helpers import CompressionDecider1, CompressionDecider2, CompressionSpec
 from .item import Item, ArchiveItem
 from .key import key_factory
 from .platform import acl_get, acl_set, set_flags, get_flags, swidth
@@ -196,7 +195,7 @@ class DownloadPipeline:
         otherwise preloaded chunks will accumulate in RemoteRepository and create a memory leak.
         """
         unpacker = msgpack.Unpacker(use_list=False)
-        for _, data in self.fetch_many(ids):
+        for data in self.fetch_many(ids):
             unpacker.feed(data)
             items = [Item(internal_dict=item) for item in unpacker]
             for item in items:
@@ -238,7 +237,9 @@ class ChunkBuffer:
         if self.buffer.tell() == 0:
             return
         self.buffer.seek(0)
-        chunks = list(Chunk(bytes(s)) for s in self.chunker.chunkify(self.buffer))
+        # The chunker returns a memoryview to its internal buffer,
+        # thus a copy is needed before resuming the chunker iterator.
+        chunks = list(bytes(s) for s in self.chunker.chunkify(self.buffer))
         self.buffer.seek(0)
         self.buffer.truncate(0)
         # Leave the last partial chunk in the buffer unless flush is True
@@ -246,7 +247,7 @@ class ChunkBuffer:
         for chunk in chunks[:end]:
             self.chunks.append(self.write_chunk(chunk))
         if end == -1:
-            self.buffer.write(chunks[-1].data)
+            self.buffer.write(chunks[-1])
 
     def is_full(self):
         return self.buffer.tell() > self.BUFFER_SIZE
@@ -260,7 +261,7 @@ class CacheChunkBuffer(ChunkBuffer):
         self.stats = stats
 
     def write_chunk(self, chunk):
-        id_, _, _ = self.cache.add_chunk(self.key.id_hash(chunk.data), chunk, self.stats, wait=False)
+        id_, _, _ = self.cache.add_chunk(self.key.id_hash(chunk), chunk, self.stats, wait=False)
         self.cache.repository.async_response(wait=False)
         return id_
 
@@ -278,7 +279,7 @@ class Archive:
 
     def __init__(self, repository, key, manifest, name, cache=None, create=False,
                  checkpoint_interval=300, numeric_owner=False, noatime=False, noctime=False, progress=False,
-                 chunker_params=CHUNKER_PARAMS, start=None, start_monotonic=None, end=None, compression=None, compression_files=None,
+                 chunker_params=CHUNKER_PARAMS, start=None, start_monotonic=None, end=None,
                  consider_part_files=False, log_json=False):
         self.cwd = os.getcwd()
         self.key = key
@@ -307,12 +308,8 @@ class Archive:
         self.pipeline = DownloadPipeline(self.repository, self.key)
         self.create = create
         if self.create:
-            self.file_compression_logger = create_logger('borg.debug.file-compression')
             self.items_buffer = CacheChunkBuffer(self.cache, self.key, self.stats)
             self.chunker = Chunker(self.key.chunk_seed, *chunker_params)
-            self.compression_decider1 = CompressionDecider1(compression or CompressionSpec('none'),
-                                                            compression_files or [])
-            key.compression_decider2 = CompressionDecider2(compression or CompressionSpec('none'))
             if name in manifest.archives:
                 raise self.AlreadyExists(name)
             self.last_checkpoint = time.monotonic()
@@ -330,7 +327,7 @@ class Archive:
             self.zeros = None
 
     def _load_meta(self, id):
-        _, data = self.key.decrypt(id, self.repository.get(id))
+        data = self.key.decrypt(id, self.repository.get(id))
         metadata = ArchiveItem(internal_dict=msgpack.unpackb(data, unicode_errors='surrogateescape'))
         if metadata.version != 1:
             raise Exception('Unknown archive metadata version')
@@ -469,7 +466,7 @@ Utilization of max. archive size: {csize_max:.0%}
         metadata = ArchiveItem(metadata)
         data = self.key.pack_and_authenticate_metadata(metadata.as_dict(), context=b'archive')
         self.id = self.key.id_hash(data)
-        self.cache.add_chunk(self.id, Chunk(data), self.stats)
+        self.cache.add_chunk(self.id, data, self.stats)
         while self.repository.async_response(wait=True) is not None:
             pass
         self.manifest.archives[name] = (self.id, metadata.time)
@@ -495,7 +492,7 @@ Utilization of max. archive size: {csize_max:.0%}
         add(self.id)
         for id, chunk in zip(self.metadata.items, self.repository.get_many(self.metadata.items)):
             add(id)
-            _, data = self.key.decrypt(id, chunk)
+            data = self.key.decrypt(id, chunk)
             unpacker.feed(data)
             for item in unpacker:
                 chunks = item.get(b'chunks')
@@ -525,7 +522,7 @@ Utilization of max. archive size: {csize_max:.0%}
         if dry_run or stdout:
             if 'chunks' in item:
                 item_chunks_size = 0
-                for _, data in self.pipeline.fetch_many([c.id for c in item.chunks], is_preloaded=True):
+                for data in self.pipeline.fetch_many([c.id for c in item.chunks], is_preloaded=True):
                     if pi:
                         pi.show(increase=len(data), info=[remove_surrogates(item.path)])
                     if stdout:
@@ -589,7 +586,7 @@ Utilization of max. archive size: {csize_max:.0%}
                 self.zeros = b'\0' * (1 << self.chunker_params[1])
             with fd:
                 ids = [c.id for c in item.chunks]
-                for _, data in self.pipeline.fetch_many(ids, is_preloaded=True):
+                for data in self.pipeline.fetch_many(ids, is_preloaded=True):
                     if pi:
                         pi.show(increase=len(data), info=[remove_surrogates(item.path)])
                     with backup_io('write'):
@@ -717,7 +714,7 @@ Utilization of max. archive size: {csize_max:.0%}
         setattr(metadata, key, value)
         data = msgpack.packb(metadata.as_dict(), unicode_errors='surrogateescape')
         new_id = self.key.id_hash(data)
-        self.cache.add_chunk(new_id, Chunk(data), self.stats)
+        self.cache.add_chunk(new_id, data, self.stats)
         self.manifest.archives[self.name] = (new_id, metadata.time)
         self.cache.chunk_decref(self.id, self.stats)
         self.id = new_id
@@ -764,7 +761,7 @@ Utilization of max. archive size: {csize_max:.0%}
             for (i, (items_id, data)) in enumerate(zip(items_ids, self.repository.get_many(items_ids))):
                 if progress:
                     pi.show(i)
-                _, data = self.key.decrypt(items_id, data)
+                data = self.key.decrypt(items_id, data)
                 unpacker.feed(data)
                 chunk_decref(items_id, stats)
                 try:
@@ -879,10 +876,10 @@ Utilization of max. archive size: {csize_max:.0%}
         self.write_checkpoint()
         return length, number
 
-    def chunk_file(self, item, cache, stats, chunk_iter, chunk_processor=None, **chunk_kw):
+    def chunk_file(self, item, cache, stats, chunk_iter, chunk_processor=None):
         if not chunk_processor:
             def chunk_processor(data):
-                chunk_entry = cache.add_chunk(self.key.id_hash(data), Chunk(data, **chunk_kw), stats, wait=False)
+                chunk_entry = cache.add_chunk(self.key.id_hash(data), data, stats, wait=False)
                 self.cache.repository.async_response(wait=False)
                 return chunk_entry
 
@@ -971,12 +968,10 @@ Utilization of max. archive size: {csize_max:.0%}
         if chunks is not None:
             item.chunks = chunks
         else:
-            compress = self.compression_decider1.decide(path)
-            self.file_compression_logger.debug('%s -> compression %s', path, compress.name)
             with backup_io('open'):
                 fh = Archive._open_rb(path)
             with os.fdopen(fh, 'rb') as fd:
-                self.chunk_file(item, cache, self.stats, backup_io_iter(self.chunker.chunkify(fd, fh)), compress=compress)
+                self.chunk_file(item, cache, self.stats, backup_io_iter(self.chunker.chunkify(fd, fh)))
             if not is_special_file:
                 # we must not memorize special files, because the contents of e.g. a
                 # block or char device will change without its mtime/size/inode changing.
@@ -1212,9 +1207,9 @@ class ArchiveChecker:
                         chunk_ids = list(reversed(chunk_ids_revd))
                         chunk_data_iter = self.repository.get_many(chunk_ids)
                 else:
+                    _chunk_id = None if chunk_id == Manifest.MANIFEST_ID else chunk_id
                     try:
-                        _chunk_id = None if chunk_id == Manifest.MANIFEST_ID else chunk_id
-                        _, data = self.key.decrypt(_chunk_id, encrypted_data)
+                        self.key.decrypt(_chunk_id, encrypted_data)
                     except IntegrityError as integrity_error:
                         self.error_found = True
                         errors += 1
@@ -1284,7 +1279,7 @@ class ArchiveChecker:
         for chunk_id, _ in self.chunks.iteritems():
             cdata = self.repository.get(chunk_id)
             try:
-                _, data = self.key.decrypt(chunk_id, cdata)
+                data = self.key.decrypt(chunk_id, cdata)
             except IntegrityError as exc:
                 logger.error('Skipping corrupted chunk: %s', exc)
                 self.error_found = True
@@ -1329,9 +1324,9 @@ class ArchiveChecker:
                 self.possibly_superseded.add(id_)
 
         def add_callback(chunk):
-            id_ = self.key.id_hash(chunk.data)
+            id_ = self.key.id_hash(chunk)
             cdata = self.key.encrypt(chunk)
-            add_reference(id_, len(chunk.data), len(cdata), cdata)
+            add_reference(id_, len(chunk), len(cdata), cdata)
             return id_
 
         def add_reference(id_, size, csize, cdata=None):
@@ -1352,7 +1347,7 @@ class ArchiveChecker:
             def replacement_chunk(size):
                 data = bytes(size)
                 chunk_id = self.key.id_hash(data)
-                cdata = self.key.encrypt(Chunk(data))
+                cdata = self.key.encrypt(data)
                 csize = len(cdata)
                 return chunk_id, size, csize, cdata
 
@@ -1461,7 +1456,7 @@ class ArchiveChecker:
                 if state > 0:
                     unpacker.resync()
                 for chunk_id, cdata in zip(items, repository.get_many(items)):
-                    _, data = self.key.decrypt(chunk_id, cdata)
+                    data = self.key.decrypt(chunk_id, cdata)
                     unpacker.feed(data)
                     try:
                         for item in unpacker:
@@ -1511,7 +1506,7 @@ class ArchiveChecker:
                     continue
                 mark_as_possibly_superseded(archive_id)
                 cdata = self.repository.get(archive_id)
-                _, data = self.key.decrypt(archive_id, cdata)
+                data = self.key.decrypt(archive_id, cdata)
                 archive = ArchiveItem(internal_dict=msgpack.unpackb(data))
                 if archive.version != 1:
                     raise Exception('Unknown archive metadata version')
@@ -1528,7 +1523,7 @@ class ArchiveChecker:
                 archive.items = items_buffer.chunks
                 data = msgpack.packb(archive.as_dict(), unicode_errors='surrogateescape')
                 new_archive_id = self.key.id_hash(data)
-                cdata = self.key.encrypt(Chunk(data))
+                cdata = self.key.encrypt(data)
                 add_reference(new_archive_id, len(data), len(cdata), cdata)
                 self.manifest.archives[info.name] = (new_archive_id, info.ts)
 
@@ -1562,7 +1557,7 @@ class ArchiveRecreater:
 
     def __init__(self, repository, manifest, key, cache, matcher,
                  exclude_caches=False, exclude_if_present=None, keep_exclude_tags=False,
-                 chunker_params=None, compression=None, compression_files=None, always_recompress=False,
+                 chunker_params=None, compression=None, always_recompress=False,
                  dry_run=False, stats=False, progress=False, file_status_printer=None,
                  checkpoint_interval=1800):
         self.repository = repository
@@ -1583,9 +1578,6 @@ class ArchiveRecreater:
         self.always_recompress = always_recompress
         self.compression = compression or CompressionSpec('none')
         self.seen_chunks = set()
-        self.compression_decider1 = CompressionDecider1(compression or CompressionSpec('none'),
-                                                        compression_files or [])
-        key.compression_decider2 = CompressionDecider2(compression or CompressionSpec('none'))
 
         self.dry_run = dry_run
         self.stats = stats
@@ -1654,24 +1646,21 @@ class ArchiveRecreater:
                 self.cache.chunk_incref(chunk_id, target.stats)
             return item.chunks
         chunk_iterator = self.iter_chunks(archive, target, list(item.chunks))
-        compress = self.compression_decider1.decide(item.path)
-        chunk_processor = partial(self.chunk_processor, target, compress)
+        chunk_processor = partial(self.chunk_processor, target)
         target.chunk_file(item, self.cache, target.stats, chunk_iterator, chunk_processor)
 
-    def chunk_processor(self, target, compress, data):
+    def chunk_processor(self, target, data):
         chunk_id = self.key.id_hash(data)
         if chunk_id in self.seen_chunks:
             return self.cache.chunk_incref(chunk_id, target.stats)
-        chunk = Chunk(data, compress=compress)
-        compression_spec, chunk = self.key.compression_decider2.decide(chunk)
         overwrite = self.recompress
         if self.recompress and not self.always_recompress and chunk_id in self.cache.chunks:
             # Check if this chunk is already compressed the way we want it
             old_chunk = self.key.decrypt(None, self.repository.get(chunk_id), decompress=False)
-            if Compressor.detect(old_chunk.data).name == compression_spec.name:
+            if Compressor.detect(old_chunk).name == self.key.compressor.decide(data).name:
                 # Stored chunk has the same compression we wanted
                 overwrite = False
-        chunk_entry = self.cache.add_chunk(chunk_id, chunk, target.stats, overwrite=overwrite, wait=False)
+        chunk_entry = self.cache.add_chunk(chunk_id, data, target.stats, overwrite=overwrite, wait=False)
         self.cache.repository.async_response(wait=False)
         self.seen_chunks.add(chunk_entry.id)
         return chunk_entry
@@ -1685,7 +1674,7 @@ class ArchiveRecreater:
             yield from target.chunker.chunkify(file)
         else:
             for chunk in chunk_iterator:
-                yield chunk.data
+                yield chunk
 
     def save(self, archive, target, comment=None, replace_original=True):
         if self.dry_run:
@@ -1756,7 +1745,7 @@ class ArchiveRecreater:
     def create_target_archive(self, name):
         target = Archive(self.repository, self.key, self.manifest, name, create=True,
                           progress=self.progress, chunker_params=self.chunker_params, cache=self.cache,
-                          checkpoint_interval=self.checkpoint_interval, compression=self.compression)
+                          checkpoint_interval=self.checkpoint_interval)
         return target
 
     def open_archive(self, name, **kwargs):

src/borg/archiver.py

@@ -34,10 +34,11 @@ from .archive import Archive, ArchiveChecker, ArchiveRecreater, Statistics, is_s
 from .archive import BackupOSError, backup_io
 from .cache import Cache
 from .constants import *  # NOQA
+from .compress import CompressionSpec
 from .crc32 import crc32
 from .helpers import EXIT_SUCCESS, EXIT_WARNING, EXIT_ERROR
 from .helpers import Error, NoManifestError, set_ec
-from .helpers import location_validator, archivename_validator, ChunkerParams, CompressionSpec, ComprSpec
+from .helpers import location_validator, archivename_validator, ChunkerParams
 from .helpers import PrefixSpec, SortBySpec, HUMAN_SORT_KEYS
 from .helpers import BaseFormatter, ItemFormatter, ArchiveFormatter
 from .helpers import format_time, format_timedelta, format_file_size, format_archive
@@ -107,6 +108,15 @@ def with_repository(fake=False, invert_fake=False, create=False, lock=True, excl
             with repository:
                 if manifest or cache:
                     kwargs['manifest'], kwargs['key'] = Manifest.load(repository)
+                    # do_recreate uses args.compression is None as in band signalling for "don't recompress",
+                    # note that it does not look at key.compressor. In this case the default compressor applies
+                    # to new chunks.
+                    #
+                    # We can't use a check like `'compression' in args` (an argparse.Namespace speciality),
+                    # since the compression attribute is set. So we need to see whether it's set to something
+                    # true-ish, like a CompressionSpec instance.
+                    if getattr(args, 'compression', False):
+                        kwargs['key'].compressor = args.compression.compressor
                 if cache:
                     with Cache(repository, kwargs['key'], kwargs['manifest'],
                                do_files=getattr(args, 'cache_files', False),
@@ -167,14 +177,14 @@ class Archiver:
                 a = next(chunks1, end)
                 if a is end:
                     return not blen - bi and next(chunks2, end) is end
-                a = memoryview(a.data)
+                a = memoryview(a)
                 alen = len(a)
                 ai = 0
             if not blen - bi:
                 b = next(chunks2, end)
                 if b is end:
                     return not alen - ai and next(chunks1, end) is end
-                b = memoryview(b.data)
+                b = memoryview(b)
                 blen = len(b)
                 bi = 0
             slicelen = min(alen - ai, blen - bi)
@@ -471,7 +481,6 @@ class Archiver:
                                   numeric_owner=args.numeric_owner, noatime=args.noatime, noctime=args.noctime,
                                   progress=args.progress,
                                   chunker_params=args.chunker_params, start=t0, start_monotonic=t0_monotonic,
-                                  compression=args.compression, compression_files=args.compression_files,
                                   log_json=args.log_json)
                 create_inner(archive, cache)
         else:
@@ -1325,8 +1334,7 @@ class Archiver:
         recreater = ArchiveRecreater(repository, manifest, key, cache, matcher,
                                      exclude_caches=args.exclude_caches, exclude_if_present=args.exclude_if_present,
                                      keep_exclude_tags=args.keep_exclude_tags, chunker_params=args.chunker_params,
-                                     compression=args.compression, compression_files=args.compression_files,
-                                     always_recompress=args.always_recompress,
+                                     compression=args.compression, always_recompress=args.always_recompress,
                                      progress=args.progress, stats=args.stats,
                                      file_status_printer=self.print_file_status,
                                      checkpoint_interval=args.checkpoint_interval,
@@ -1387,7 +1395,7 @@ class Archiver:
         archive = Archive(repository, key, manifest, args.location.archive,
                           consider_part_files=args.consider_part_files)
         for i, item_id in enumerate(archive.metadata.items):
-            _, data = key.decrypt(item_id, repository.get(item_id))
+            data = key.decrypt(item_id, repository.get(item_id))
             filename = '%06d_%s.items' % (i, bin_to_hex(item_id))
             print('Dumping', filename)
             with open(filename, 'wb') as fd:
@@ -1417,7 +1425,7 @@ class Archiver:
             fd.write(do_indent(prepare_dump_dict(archive_meta_orig)))
             fd.write(',\n')
 
-            _, data = key.decrypt(archive_meta_orig[b'id'], repository.get(archive_meta_orig[b'id']))
+            data = key.decrypt(archive_meta_orig[b'id'], repository.get(archive_meta_orig[b'id']))
             archive_org_dict = msgpack.unpackb(data, object_hook=StableDict, unicode_errors='surrogateescape')
 
             fd.write('    "_meta":\n')
@@ -1428,7 +1436,7 @@ class Archiver:
             unpacker = msgpack.Unpacker(use_list=False, object_hook=StableDict)
             first = True
             for item_id in archive_org_dict[b'items']:
-                _, data = key.decrypt(item_id, repository.get(item_id))
+                data = key.decrypt(item_id, repository.get(item_id))
                 unpacker.feed(data)
                 for item in unpacker:
                     item = prepare_dump_dict(item)
@@ -1452,7 +1460,7 @@ class Archiver:
     def do_debug_dump_manifest(self, args, repository, manifest, key):
         """dump decoded repository manifest"""
 
-        _, data = key.decrypt(None, repository.get(manifest.MANIFEST_ID))
+        data = key.decrypt(None, repository.get(manifest.MANIFEST_ID))
 
         meta = prepare_dump_dict(msgpack.fallback.unpackb(data, object_hook=StableDict, unicode_errors='surrogateescape'))
 
@@ -1476,7 +1484,7 @@ class Archiver:
             for id in result:
                 cdata = repository.get(id)
                 give_id = id if id != Manifest.MANIFEST_ID else None
-                _, data = key.decrypt(give_id, cdata)
+                data = key.decrypt(give_id, cdata)
                 filename = '%06d_%s.obj' % (i, bin_to_hex(id))
                 print('Dumping', filename)
                 with open(filename, 'wb') as fd:
@@ -1789,43 +1797,13 @@ class Archiver:
             For compressible data, it uses the given C[,L] compression - with C[,L]
             being any valid compression specifier.
 
-        The decision about which compression to use is done by borg like this:
-
-        1. find a compression specifier (per file):
-           match the path/filename against all patterns in all --compression-from
-           files (if any). If a pattern matches, use the compression spec given for
-           that pattern. If no pattern matches (and also if you do not give any
-           --compression-from option), default to the compression spec given by
-           --compression. See docs/misc/compression.conf for an example config.
-
-        2. if the found compression spec is not "auto", the decision is taken:
-           use the found compression spec.
-
-        3. if the found compression spec is "auto", test compressibility of each
-           chunk using lz4.
-           If it is compressible, use the C,[L] compression spec given within the
-           "auto" specifier. If it is not compressible, use no compression.
-
         Examples::
 
             borg create --compression lz4 REPO::ARCHIVE data
             borg create --compression zlib REPO::ARCHIVE data
             borg create --compression zlib,1 REPO::ARCHIVE data
             borg create --compression auto,lzma,6 REPO::ARCHIVE data
-            borg create --compression-from compression.conf --compression auto,lzma ...
-
-        compression.conf has entries like::
-
-            # example config file for --compression-from option
-            #
-            # Format of non-comment / non-empty lines:
-            # <compression-spec>:<path/filename pattern>
-            # compression-spec is same format as for --compression option
-            # path/filename pattern is same format as for --exclude option
-            none:*.gz
-            none:*.zip
-            none:*.mp3
-            none:*.ogg
+            borg create --compression auto,lzma ...
 
         General remarks:
 
@@ -2411,14 +2389,9 @@ class Archiver:
                                    help='specify the chunker parameters (CHUNK_MIN_EXP, CHUNK_MAX_EXP, '
                                         'HASH_MASK_BITS, HASH_WINDOW_SIZE). default: %d,%d,%d,%d' % CHUNKER_PARAMS)
         archive_group.add_argument('-C', '--compression', dest='compression',
-                                   type=CompressionSpec, default=ComprSpec(name='lz4', spec=None), metavar='COMPRESSION',
+                                   type=CompressionSpec, default=CompressionSpec('lz4'), metavar='COMPRESSION',
                                    help='select compression algorithm, see the output of the '
                                         '"borg help compression" command for details.')
-        archive_group.add_argument('--compression-from', dest='compression_files',
-                                   type=argparse.FileType('r'), action='append',
-                                   metavar='COMPRESSIONCONFIG',
-                                   help='read compression patterns from COMPRESSIONCONFIG, see the output of the '
-                                        '"borg help compression" command for details.')
 
         subparser.add_argument('location', metavar='ARCHIVE',
                                type=location_validator(archive=True),
@@ -2954,7 +2927,7 @@ class Archiver:
         resulting archive will only contain files from these PATHs.
 
         Note that all paths in an archive are relative, therefore absolute patterns/paths
-        will *not* match (--exclude, --exclude-from, --compression-from, PATHs).
+        will *not* match (--exclude, --exclude-from, PATHs).
 
         --compression: all chunks seen will be stored using the given method.
         Due to how Borg stores compressed size information this might display
@@ -3049,11 +3022,6 @@ class Archiver:
         archive_group.add_argument('--always-recompress', dest='always_recompress', action='store_true',
                                    help='always recompress chunks, don\'t skip chunks already compressed with the same '
                                         'algorithm.')
-        archive_group.add_argument('--compression-from', dest='compression_files',
-                                   type=argparse.FileType('r'), action='append',
-                                   metavar='COMPRESSIONCONFIG',
-                                   help='read compression patterns from COMPRESSIONCONFIG, see the output of the '
-                                        '"borg help compression" command for details.')
         archive_group.add_argument('--chunker-params', dest='chunker_params',
                                    type=ChunkerParams, default=CHUNKER_PARAMS,
                                    metavar='PARAMS',

src/borg/cache.py

@@ -424,14 +424,14 @@ Chunk index:    {0.total_unique_chunks:20d} {0.total_chunks:20d}"""
 
         def fetch_and_build_idx(archive_id, repository, key, chunk_idx):
             cdata = repository.get(archive_id)
-            _, data = key.decrypt(archive_id, cdata)
+            data = key.decrypt(archive_id, cdata)
             chunk_idx.add(archive_id, 1, len(data), len(cdata))
             archive = ArchiveItem(internal_dict=msgpack.unpackb(data))
             if archive.version != 1:
                 raise Exception('Unknown archive metadata version')
             unpacker = msgpack.Unpacker()
             for item_id, chunk in zip(archive.items, repository.get_many(archive.items)):
-                _, data = key.decrypt(item_id, chunk)
+                data = key.decrypt(item_id, chunk)
                 chunk_idx.add(item_id, 1, len(data), len(chunk))
                 unpacker.feed(data)
                 for item in unpacker:
@@ -527,7 +527,7 @@ Chunk index:    {0.total_unique_chunks:20d} {0.total_chunks:20d}"""
     def add_chunk(self, id, chunk, stats, overwrite=False, wait=True):
         if not self.txn_active:
             self.begin_txn()
-        size = len(chunk.data)
+        size = len(chunk)
         refcount = self.seen_chunk(id, size)
         if refcount and not overwrite:
             return self.chunk_incref(id, stats)

src/borg/compress.pyx

@@ -1,4 +1,22 @@
+"""
+borg.compress
+=============
+
+Compression is applied to chunks after ID hashing (so the ID is a direct function of the
+plain chunk, compression is irrelevant to it), and of course before encryption.
+
+The "auto" mode (e.g. --compression auto,lzma,4) is implemented as a meta Compressor,
+meaning that Auto acts like a Compressor, but defers actual work to others (namely
+LZ4 as a heuristic whether compression is worth it, and the specified Compressor
+for the actual compression).
+
+Decompression is normally handled through Compressor.decompress which will detect
+which compressor has been used to compress the data and dispatch to the correct
+decompressor.
+"""
+
 import zlib
+
 try:
     import lzma
 except ImportError:
@@ -6,7 +24,7 @@ except ImportError:
 
 from .helpers import Buffer, DecompressionError
 
-API_VERSION = '1.1_02'
+API_VERSION = '1.1_03'
 
 cdef extern from "lz4.h":
     int LZ4_compress_limitedOutput(const char* source, char* dest, int inputSize, int maxOutputSize) nogil
@@ -34,11 +52,34 @@ cdef class CompressorBase:
     def __init__(self, **kwargs):
         pass
 
+    def decide(self, data):
+        """
+        Return which compressor will perform the actual compression for *data*.
+
+        This exists for a very specific case: If borg recreate is instructed to recompress
+        using Auto compression it needs to determine the _actual_ target compression of a chunk
+        in order to detect whether it should be recompressed.
+        
+        For all Compressors that are not Auto this always returns *self*.
+        """
+        return self
+
     def compress(self, data):
+        """
+        Compress *data* (bytes) and return bytes result. Prepend the ID bytes of this compressor,
+        which is needed so that the correct decompressor can be used for decompression.
+        """
         # add ID bytes
         return self.ID + data
 
     def decompress(self, data):
+        """
+        Decompress *data* (bytes) and return bytes result. The leading Compressor ID
+        bytes need to be present.
+
+        Only handles input generated by _this_ Compressor - for a general purpose
+        decompression method see *Compressor.decompress*.
+        """
         # strip ID bytes
         return data[2:]
 
@@ -179,12 +220,64 @@ class ZLIB(CompressorBase):
             raise DecompressionError(str(e)) from None
 
 
+class Auto(CompressorBase):
+    """
+    Meta-Compressor that decides which compression to use based on LZ4's ratio.
+
+    As a meta-Compressor the actual compression is deferred to other Compressors,
+    therefore this Compressor has no ID, no detect() and no decompress().
+    """
+
+    ID = None
+    name = 'auto'
+
+    def __init__(self, compressor):
+        super().__init__()
+        self.compressor = compressor
+        self.lz4 = get_compressor('lz4')
+        self.none = get_compressor('none')
+
+    def _decide(self, data):
+        """
+        Decides what to do with *data*. Returns (compressor, lz4_data).
+
+        *lz4_data* is the LZ4 result if *compressor* is LZ4 as well, otherwise it is None.
+        """
+        lz4_data = self.lz4.compress(data)
+        ratio = len(lz4_data) / len(data)
+        if ratio < 0.97:
+            return self.compressor, None
+        elif ratio < 1:
+            return self.lz4, lz4_data
+        else:
+            return self.none, None
+
+    def decide(self, data):
+        return self._decide(data)[0]
+
+    def compress(self, data):
+        compressor, lz4_data = self._decide(data)
+        if lz4_data is None:
+            return compressor.compress(data)
+        else:
+            return lz4_data
+
+    def decompress(self, data):
+        raise NotImplementedError
+
+    def detect(cls, data):
+        raise NotImplementedError
+
+
+# Maps valid compressor names to their class
 COMPRESSOR_TABLE = {
     CNONE.name: CNONE,
     LZ4.name: LZ4,
     ZLIB.name: ZLIB,
     LZMA.name: LZMA,
+    Auto.name: Auto,
 }
+# List of possible compression types. Does not include Auto, since it is a meta-Compressor.
 COMPRESSOR_LIST = [LZ4, CNONE, ZLIB, LZMA, ]  # check fast stuff first
 
 def get_compressor(name, **kwargs):
@@ -216,3 +309,42 @@ class Compressor:
                 return cls
         else:
             raise ValueError('No decompressor for this data found: %r.', data[:2])
+
+
+class CompressionSpec:
+    def __init__(self, s):
+        values = s.split(',')
+        count = len(values)
+        if count < 1:
+            raise ValueError
+        # --compression algo[,level]
+        self.name = values[0]
+        if self.name in ('none', 'lz4', ):
+            return
+        elif self.name in ('zlib', 'lzma', ):
+            if count < 2:
+                level = 6  # default compression level in py stdlib
+            elif count == 2:
+                level = int(values[1])
+                if not 0 <= level <= 9:
+                    raise ValueError
+            else:
+                raise ValueError
+            self.level = level
+        elif self.name == 'auto':
+            if 2 <= count <= 3:
+                compression = ','.join(values[1:])
+            else:
+                raise ValueError
+            self.inner = CompressionSpec(compression)
+        else:
+            raise ValueError
+
+    @property
+    def compressor(self):
+        if self.name in ('none', 'lz4', ):
+            return get_compressor(self.name)
+        elif self.name in ('zlib', 'lzma', ):
+            return get_compressor(self.name, level=self.level)
+        elif self.name == 'auto':
+            return get_compressor(self.name, compressor=self.inner.compressor)

src/borg/fuse.py

@@ -144,7 +144,7 @@ class FuseOperations(llfuse.Operations):
         self.file_versions = {}  # for versions mode: original path -> version
         unpacker = msgpack.Unpacker()
         for key, chunk in zip(archive.metadata.items, self.repository.get_many(archive.metadata.items)):
-            _, data = self.key.decrypt(key, chunk)
+            data = self.key.decrypt(key, chunk)
             unpacker.feed(data)
             for item in unpacker:
                 item = Item(internal_dict=item)
@@ -340,7 +340,7 @@ class FuseOperations(llfuse.Operations):
                     # evict fully read chunk from cache
                     del self.data_cache[id]
             else:
-                _, data = self.key.decrypt(id, self.repository.get(id))
+                data = self.key.decrypt(id, self.repository.get(id))
                 if offset + n < len(data):
                     # chunk was only partially read, cache it
                     self.data_cache[id] = data

src/borg/helpers.py

@@ -44,13 +44,6 @@ from . import hashindex
 from . import shellpattern
 from .constants import *  # NOQA
 
-# meta dict, data bytes
-_Chunk = namedtuple('_Chunk', 'meta data')
-
-
-def Chunk(data, **meta):
-    return _Chunk(meta, data)
-
 
 '''
 The global exit_code variable is used so that modules other than archiver can increase the program exit code if a
@@ -123,7 +116,7 @@ def check_extension_modules():
         raise ExtensionModuleError
     if chunker.API_VERSION != '1.1_01':
         raise ExtensionModuleError
-    if compress.API_VERSION != '1.1_02':
+    if compress.API_VERSION != '1.1_03':
         raise ExtensionModuleError
     if crypto.API_VERSION != '1.1_01':
         raise ExtensionModuleError
@@ -247,7 +240,7 @@ class Manifest:
         if not key:
             key = key_factory(repository, cdata)
         manifest = cls(key, repository)
-        data = key.decrypt(None, cdata).data
+        data = key.decrypt(None, cdata)
         manifest_dict, manifest.tam_verified = key.unpack_and_verify_manifest(data, force_tam_not_required=force_tam_not_required)
         m = ManifestItem(internal_dict=manifest_dict)
         manifest.id = key.id_hash(data)
@@ -292,7 +285,7 @@ class Manifest:
         self.tam_verified = True
         data = self.key.pack_and_authenticate_metadata(manifest.as_dict())
         self.id = self.key.id_hash(data)
-        self.repository.put(self.MANIFEST_ID, self.key.encrypt(Chunk(data, compression={'name': 'none'})))
+        self.repository.put(self.MANIFEST_ID, self.key.encrypt(data))
 
 
 def prune_within(archives, within):
@@ -726,37 +719,6 @@ def ChunkerParams(s):
     return int(chunk_min), int(chunk_max), int(chunk_mask), int(window_size)
 
 
-ComprSpec = namedtuple('ComprSpec', ('name', 'spec'))
-
-
-def CompressionSpec(s):
-    values = s.split(',')
-    count = len(values)
-    if count < 1:
-        raise ValueError
-    # --compression algo[,level]
-    name = values[0]
-    if name in ('none', 'lz4', ):
-        return ComprSpec(name=name, spec=None)
-    if name in ('zlib', 'lzma', ):
-        if count < 2:
-            level = 6  # default compression level in py stdlib
-        elif count == 2:
-            level = int(values[1])
-            if not 0 <= level <= 9:
-                raise ValueError
-        else:
-            raise ValueError
-        return ComprSpec(name=name, spec=level)
-    if name == 'auto':
-        if 2 <= count <= 3:
-            compression = ','.join(values[1:])
-        else:
-            raise ValueError
-        return ComprSpec(name=name, spec=CompressionSpec(compression))
-    raise ValueError
-
-
 def dir_is_cachedir(path):
     """Determines whether the specified path is a cache directory (and
     therefore should potentially be excluded from the backup) according to
@@ -1940,7 +1902,7 @@ class ItemFormatter(BaseFormatter):
         if 'chunks' not in item:
             return ""
         hash = hashlib.new(hash_function)
-        for _, data in self.archive.pipeline.fetch_many([c.id for c in item.chunks]):
+        for data in self.archive.pipeline.fetch_many([c.id for c in item.chunks]):
             hash.update(data)
         return hash.hexdigest()
 
@@ -1965,7 +1927,7 @@ class ChunkIteratorFileWrapper:
         if not remaining:
             try:
                 chunk = next(self.chunk_iterator)
-                self.chunk = memoryview(chunk.data)
+                self.chunk = memoryview(chunk)
             except StopIteration:
                 self.exhausted = True
                 return 0  # EOF
@@ -2127,73 +2089,6 @@ def clean_lines(lines, lstrip=None, rstrip=None, remove_empty=True, remove_comme
         yield line
 
 
-class CompressionDecider1:
-    def __init__(self, compression, compression_files):
-        """
-        Initialize a CompressionDecider instance (and read config files, if needed).
-
-        :param compression: default CompressionSpec (e.g. from --compression option)
-        :param compression_files: list of compression config files (e.g. from --compression-from) or
-                                  a list of other line iterators
-        """
-        self.compression = compression
-        if not compression_files:
-            self.matcher = None
-        else:
-            self.matcher = PatternMatcher(fallback=compression)
-            for file in compression_files:
-                try:
-                    for line in clean_lines(file):
-                        try:
-                            compr_spec, fn_pattern = line.split(':', 1)
-                        except:
-                            continue
-                        self.matcher.add([parse_pattern(fn_pattern)], CompressionSpec(compr_spec))
-                finally:
-                    if hasattr(file, 'close'):
-                        file.close()
-
-    def decide(self, path):
-        if self.matcher is not None:
-            return self.matcher.match(path)
-        return self.compression
-
-
-class CompressionDecider2:
-    logger = create_logger('borg.debug.file-compression')
-
-    def __init__(self, compression):
-        self.compression = compression
-
-    def decide(self, chunk):
-        # nothing fancy here yet: we either use what the metadata says or the default
-        # later, we can decide based on the chunk data also.
-        # if we compress the data here to decide, we can even update the chunk data
-        # and modify the metadata as desired.
-        compr_spec = chunk.meta.get('compress', self.compression)
-        if compr_spec.name == 'auto':
-            # we did not decide yet, use heuristic:
-            compr_spec, chunk = self.heuristic_lz4(compr_spec, chunk)
-        return compr_spec, chunk
-
-    def heuristic_lz4(self, compr_args, chunk):
-        from .compress import get_compressor
-        meta, data = chunk
-        lz4 = get_compressor('lz4')
-        cdata = lz4.compress(data)
-        data_len = len(data)
-        cdata_len = len(cdata)
-        if cdata_len < 0.97 * data_len:
-            compr_spec = compr_args.spec
-        else:
-            # uncompressible - we could have a special "uncompressible compressor"
-            # that marks such data as uncompressible via compression-type metadata.
-            compr_spec = CompressionSpec('none')
-        self.logger.debug("len(data) == %d, len(lz4(data)) == %d, ratio == %.3f, choosing %s", data_len, cdata_len, cdata_len/data_len, compr_spec)
-        meta['compress'] = compr_spec
-        return compr_spec, Chunk(data, **meta)
-
-
 class ErrorIgnoringTextIOWrapper(io.TextIOWrapper):
     def read(self, n):
         if not self.closed:

src/borg/key.py

@@ -13,14 +13,13 @@ from .logger import create_logger
 logger = create_logger()
 
 from .constants import *  # NOQA
-from .compress import Compressor, get_compressor
+from .compress import Compressor
 from .crypto import AES, bytes_to_long, bytes_to_int, num_aes_blocks, hmac_sha256, blake2b_256, hkdf_hmac_sha512
-from .helpers import Chunk, StableDict
+from .helpers import StableDict
 from .helpers import Error, IntegrityError
 from .helpers import yes
 from .helpers import get_keys_dir, get_security_dir
 from .helpers import bin_to_hex
-from .helpers import CompressionDecider2, CompressionSpec
 from .item import Key, EncryptedKey
 from .platform import SaveFile
 from .nonces import NonceManager
@@ -143,21 +142,16 @@ class KeyBase:
         self.TYPE_STR = bytes([self.TYPE])
         self.repository = repository
         self.target = None  # key location file path / repo obj
-        self.compression_decider2 = CompressionDecider2(CompressionSpec('none'))
-        self.compressor = Compressor('none')  # for decompression
+        # Some commands write new chunks (e.g. rename) but don't take a --compression argument. This duplicates
+        # the default used by those commands who do take a --compression argument.
+        self.compressor = Compressor('lz4')
+        self.decompress = self.compressor.decompress
         self.tam_required = True
 
     def id_hash(self, data):
         """Return HMAC hash using the "id" HMAC key
         """
 
-    def compress(self, chunk):
-        compr_args, chunk = self.compression_decider2.decide(chunk)
-        compressor = Compressor(name=compr_args.name, level=compr_args.spec)
-        meta, data = chunk
-        data = compressor.compress(data)
-        return Chunk(data, **meta)
-
     def encrypt(self, chunk):
         pass
 
@@ -258,8 +252,8 @@ class PlaintextKey(KeyBase):
         return sha256(data).digest()
 
     def encrypt(self, chunk):
-        chunk = self.compress(chunk)
-        return b''.join([self.TYPE_STR, chunk.data])
+        data = self.compressor.compress(chunk)
+        return b''.join([self.TYPE_STR, data])
 
     def decrypt(self, id, data, decompress=True):
         if data[0] != self.TYPE:
@@ -267,10 +261,10 @@ class PlaintextKey(KeyBase):
             raise IntegrityError('Chunk %s: Invalid encryption envelope' % id_str)
         payload = memoryview(data)[1:]
         if not decompress:
-            return Chunk(payload)
-        data = self.compressor.decompress(payload)
+            return payload
+        data = self.decompress(payload)
         self.assert_id(id, data)
-        return Chunk(data)
+        return data
 
     def _tam_key(self, salt, context):
         return salt + context
@@ -336,10 +330,10 @@ class AESKeyBase(KeyBase):
     MAC = hmac_sha256
 
     def encrypt(self, chunk):
-        chunk = self.compress(chunk)
-        self.nonce_manager.ensure_reservation(num_aes_blocks(len(chunk.data)))
+        data = self.compressor.compress(chunk)
+        self.nonce_manager.ensure_reservation(num_aes_blocks(len(data)))
         self.enc_cipher.reset()
-        data = b''.join((self.enc_cipher.iv[8:], self.enc_cipher.encrypt(chunk.data)))
+        data = b''.join((self.enc_cipher.iv[8:], self.enc_cipher.encrypt(data)))
         assert (self.MAC is blake2b_256 and len(self.enc_hmac_key) == 128 or
                 self.MAC is hmac_sha256 and len(self.enc_hmac_key) == 32)
         hmac = self.MAC(self.enc_hmac_key, data)
@@ -361,10 +355,10 @@ class AESKeyBase(KeyBase):
         self.dec_cipher.reset(iv=PREFIX + data[33:41])
         payload = self.dec_cipher.decrypt(data_view[41:])
         if not decompress:
-            return Chunk(payload)
-        data = self.compressor.decompress(payload)
+            return payload
+        data = self.decompress(payload)
         self.assert_id(id, data)
-        return Chunk(data)
+        return data
 
     def extract_nonce(self, payload):
         if not (payload[0] == self.TYPE or
@@ -748,18 +742,18 @@ class AuthenticatedKey(ID_BLAKE2b_256, RepoKey):
     STORAGE = KeyBlobStorage.REPO
 
     def encrypt(self, chunk):
-        chunk = self.compress(chunk)
-        return b''.join([self.TYPE_STR, chunk.data])
+        data = self.compressor.compress(chunk)
+        return b''.join([self.TYPE_STR, data])
 
     def decrypt(self, id, data, decompress=True):
         if data[0] != self.TYPE:
             raise IntegrityError('Chunk %s: Invalid envelope' % bin_to_hex(id))
         payload = memoryview(data)[1:]
         if not decompress:
-            return Chunk(payload)
-        data = self.compressor.decompress(payload)
+            return payload
+        data = self.decompress(payload)
         self.assert_id(id, data)
-        return Chunk(data)
+        return data
 
 
 AVAILABLE_KEY_TYPES = (

src/borg/testsuite/archive.py

@@ -72,8 +72,8 @@ class MockCache:
         self.repository = self.MockRepo()
 
     def add_chunk(self, id, chunk, stats=None, wait=True):
-        self.objects[id] = chunk.data
-        return id, len(chunk.data), len(chunk.data)
+        self.objects[id] = chunk
+        return id, len(chunk), len(chunk)
 
 
 class ArchiveTimestampTestCase(BaseTestCase):

src/borg/testsuite/archiver.py

@@ -34,7 +34,7 @@ from ..cache import Cache
 from ..constants import *  # NOQA
 from ..crypto import bytes_to_long, num_aes_blocks
 from ..helpers import PatternMatcher, parse_pattern, Location, get_security_dir
-from ..helpers import Chunk, Manifest
+from ..helpers import Manifest
 from ..helpers import EXIT_SUCCESS, EXIT_WARNING, EXIT_ERROR
 from ..helpers import bin_to_hex
 from ..item import Item
@@ -2449,7 +2449,7 @@ class ArchiverCheckTestCase(ArchiverTestCaseBase):
                 'version': 1,
             })
             archive_id = key.id_hash(archive)
-            repository.put(archive_id, key.encrypt(Chunk(archive)))
+            repository.put(archive_id, key.encrypt(archive))
             repository.commit()
         self.cmd('check', self.repository_location, exit_code=1)
         self.cmd('check', '--repair', self.repository_location, exit_code=0)
@@ -2537,12 +2537,12 @@ class ManifestAuthenticationTest(ArchiverTestCaseBase):
     def spoof_manifest(self, repository):
         with repository:
             _, key = Manifest.load(repository)
-            repository.put(Manifest.MANIFEST_ID, key.encrypt(Chunk(msgpack.packb({
+            repository.put(Manifest.MANIFEST_ID, key.encrypt(msgpack.packb({
                 'version': 1,
                 'archives': {},
                 'config': {},
                 'timestamp': (datetime.utcnow() + timedelta(days=1)).isoformat(),
-            }))))
+            })))
             repository.commit()
 
     def test_fresh_init_tam_required(self):
@@ -2550,11 +2550,11 @@ class ManifestAuthenticationTest(ArchiverTestCaseBase):
         repository = Repository(self.repository_path, exclusive=True)
         with repository:
             manifest, key = Manifest.load(repository)
-            repository.put(Manifest.MANIFEST_ID, key.encrypt(Chunk(msgpack.packb({
+            repository.put(Manifest.MANIFEST_ID, key.encrypt(msgpack.packb({
                 'version': 1,
                 'archives': {},
                 'timestamp': (datetime.utcnow() + timedelta(days=1)).isoformat(),
-            }))))
+            })))
             repository.commit()
 
         with pytest.raises(TAMRequiredError):
@@ -2570,9 +2570,9 @@ class ManifestAuthenticationTest(ArchiverTestCaseBase):
             key.tam_required = False
             key.change_passphrase(key._passphrase)
 
-            manifest = msgpack.unpackb(key.decrypt(None, repository.get(Manifest.MANIFEST_ID)).data)
+            manifest = msgpack.unpackb(key.decrypt(None, repository.get(Manifest.MANIFEST_ID)))
             del manifest[b'tam']
-            repository.put(Manifest.MANIFEST_ID, key.encrypt(Chunk(msgpack.packb(manifest))))
+            repository.put(Manifest.MANIFEST_ID, key.encrypt(msgpack.packb(manifest)))
             repository.commit()
         output = self.cmd('list', '--debug', self.repository_location)
         assert 'archive1234' in output
@@ -2844,8 +2844,8 @@ def test_get_args():
 
 def test_compare_chunk_contents():
     def ccc(a, b):
-        chunks_a = [Chunk(data) for data in a]
-        chunks_b = [Chunk(data) for data in b]
+        chunks_a = [data for data in a]
+        chunks_b = [data for data in b]
         compare1 = Archiver.compare_chunk_contents(iter(chunks_a), iter(chunks_b))
         compare2 = Archiver.compare_chunk_contents(iter(chunks_b), iter(chunks_a))
         assert compare1 == compare2

src/borg/testsuite/compress.py

@@ -7,7 +7,7 @@ except ImportError:
 
 import pytest
 
-from ..compress import get_compressor, Compressor, CNONE, ZLIB, LZ4
+from ..compress import get_compressor, Compressor, CompressionSpec, CNONE, ZLIB, LZ4, LZMA, Auto
 
 
 buffer = bytes(2**16)
@@ -107,3 +107,48 @@ def test_compressor():
     for params in params_list:
         c = Compressor(**params)
         assert data == c.decompress(c.compress(data))
+
+
+def test_auto():
+    compressor = CompressionSpec('auto,zlib,9').compressor
+
+    compressed = compressor.compress(bytes(500))
+    assert Compressor.detect(compressed) == ZLIB
+
+    compressed = compressor.compress(b'\x00\xb8\xa3\xa2-O\xe1i\xb6\x12\x03\xc21\xf3\x8a\xf78\\\x01\xa5b\x07\x95\xbeE\xf8\xa3\x9ahm\xb1~')
+    assert Compressor.detect(compressed) == CNONE
+
+
+def test_compression_specs():
+    with pytest.raises(ValueError):
+        CompressionSpec('')
+
+    assert isinstance(CompressionSpec('none').compressor, CNONE)
+    assert isinstance(CompressionSpec('lz4').compressor, LZ4)
+
+    zlib = CompressionSpec('zlib').compressor
+    assert isinstance(zlib, ZLIB)
+    assert zlib.level == 6
+    zlib = CompressionSpec('zlib,0').compressor
+    assert isinstance(zlib, ZLIB)
+    assert zlib.level == 0
+    zlib = CompressionSpec('zlib,9').compressor
+    assert isinstance(zlib, ZLIB)
+    assert zlib.level == 9
+    with pytest.raises(ValueError):
+        CompressionSpec('zlib,9,invalid')
+
+    lzma = CompressionSpec('lzma').compressor
+    assert isinstance(lzma, LZMA)
+    assert lzma.level == 6
+    lzma = CompressionSpec('lzma,0').compressor
+    assert isinstance(lzma, LZMA)
+    assert lzma.level == 0
+    lzma = CompressionSpec('lzma,9').compressor
+    assert isinstance(lzma, LZMA)
+    assert lzma.level == 9
+
+    with pytest.raises(ValueError):
+        CompressionSpec('lzma,9,invalid')
+    with pytest.raises(ValueError):
+        CompressionSpec('invalid')

src/borg/testsuite/helpers.py

@@ -21,10 +21,9 @@ from ..helpers import get_cache_dir, get_keys_dir, get_security_dir
 from ..helpers import is_slow_msgpack
 from ..helpers import yes, TRUISH, FALSISH, DEFAULTISH
 from ..helpers import StableDict, int_to_bigint, bigint_to_int, bin_to_hex
-from ..helpers import parse_timestamp, ChunkIteratorFileWrapper, ChunkerParams, Chunk
+from ..helpers import parse_timestamp, ChunkIteratorFileWrapper, ChunkerParams
 from ..helpers import ProgressIndicatorPercent, ProgressIndicatorEndless
 from ..helpers import load_exclude_file, load_pattern_file
-from ..helpers import CompressionSpec, ComprSpec, CompressionDecider1, CompressionDecider2
 from ..helpers import parse_pattern, PatternMatcher
 from ..helpers import PathFullPattern, PathPrefixPattern, FnmatchPattern, ShellPattern, RegexPattern
 from ..helpers import swidth_slice
@@ -698,25 +697,6 @@ def test_pattern_matcher():
     assert PatternMatcher(fallback="hey!").fallback == "hey!"
 
 
-def test_compression_specs():
-    with pytest.raises(ValueError):
-        CompressionSpec('')
-    assert CompressionSpec('none') == ComprSpec(name='none', spec=None)
-    assert CompressionSpec('lz4') == ComprSpec(name='lz4', spec=None)
-    assert CompressionSpec('zlib') == ComprSpec(name='zlib', spec=6)
-    assert CompressionSpec('zlib,0') == ComprSpec(name='zlib', spec=0)
-    assert CompressionSpec('zlib,9') == ComprSpec(name='zlib', spec=9)
-    with pytest.raises(ValueError):
-        CompressionSpec('zlib,9,invalid')
-    assert CompressionSpec('lzma') == ComprSpec(name='lzma', spec=6)
-    assert CompressionSpec('lzma,0') == ComprSpec(name='lzma', spec=0)
-    assert CompressionSpec('lzma,9') == ComprSpec(name='lzma', spec=9)
-    with pytest.raises(ValueError):
-        CompressionSpec('lzma,9,invalid')
-    with pytest.raises(ValueError):
-        CompressionSpec('invalid')
-
-
 def test_chunkerparams():
     assert ChunkerParams('19,23,21,4095') == (19, 23, 21, 4095)
     assert ChunkerParams('10,23,16,4095') == (10, 23, 16, 4095)
@@ -1178,7 +1158,7 @@ def test_partial_format():
 
 
 def test_chunk_file_wrapper():
-    cfw = ChunkIteratorFileWrapper(iter([Chunk(b'abc'), Chunk(b'def')]))
+    cfw = ChunkIteratorFileWrapper(iter([b'abc', b'def']))
     assert cfw.read(2) == b'ab'
     assert cfw.read(50) == b'cdef'
     assert cfw.exhausted
@@ -1220,38 +1200,6 @@ data2
     assert list(clean_lines(conf, remove_comments=False)) == ['#comment', 'data1 #data1', 'data2', 'data3', ]
 
 
-def test_compression_decider1():
-    default = CompressionSpec('zlib')
-    conf = """
-# use super-fast lz4 compression on huge VM files in this path:
-lz4:/srv/vm_disks
-
-# jpeg or zip files do not compress:
-none:*.jpeg
-none:*.zip
-""".splitlines()
-
-    cd = CompressionDecider1(default, [])  # no conf, always use default
-    assert cd.decide('/srv/vm_disks/linux').name == 'zlib'
-    assert cd.decide('test.zip').name == 'zlib'
-    assert cd.decide('test').name == 'zlib'
-
-    cd = CompressionDecider1(default, [conf, ])
-    assert cd.decide('/srv/vm_disks/linux').name == 'lz4'
-    assert cd.decide('test.zip').name == 'none'
-    assert cd.decide('test').name == 'zlib'  # no match in conf, use default
-
-
-def test_compression_decider2():
-    default = CompressionSpec('zlib')
-
-    cd = CompressionDecider2(default)
-    compr_spec, chunk = cd.decide(Chunk(None))
-    assert compr_spec.name == 'zlib'
-    compr_spec, chunk = cd.decide(Chunk(None, compress=CompressionSpec('lzma')))
-    assert compr_spec.name == 'lzma'
-
-
 def test_format_line():
     data = dict(foo='bar baz')
     assert format_line('', data) == ''

src/borg/testsuite/key.py

@@ -9,7 +9,7 @@ import msgpack
 
 from ..crypto import bytes_to_long, num_aes_blocks
 from ..helpers import Location
-from ..helpers import Chunk, StableDict
+from ..helpers import StableDict
 from ..helpers import IntegrityError
 from ..helpers import get_security_dir
 from ..key import PlaintextKey, PassphraseKey, KeyfileKey, RepoKey, Blake2KeyfileKey, Blake2RepoKey, AuthenticatedKey
@@ -104,17 +104,17 @@ class TestKey:
 
     def test_plaintext(self):
         key = PlaintextKey.create(None, None)
-        chunk = Chunk(b'foo')
-        assert hexlify(key.id_hash(chunk.data)) == b'2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae'
-        assert chunk == key.decrypt(key.id_hash(chunk.data), key.encrypt(chunk))
+        chunk = b'foo'
+        assert hexlify(key.id_hash(chunk)) == b'2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae'
+        assert chunk == key.decrypt(key.id_hash(chunk), key.encrypt(chunk))
 
     def test_keyfile(self, monkeypatch, keys_dir):
         monkeypatch.setenv('BORG_PASSPHRASE', 'test')
         key = KeyfileKey.create(self.MockRepository(), self.MockArgs())
         assert bytes_to_long(key.enc_cipher.iv, 8) == 0
-        manifest = key.encrypt(Chunk(b'ABC'))
+        manifest = key.encrypt(b'ABC')
         assert key.extract_nonce(manifest) == 0
-        manifest2 = key.encrypt(Chunk(b'ABC'))
+        manifest2 = key.encrypt(b'ABC')
         assert manifest != manifest2
         assert key.decrypt(None, manifest) == key.decrypt(None, manifest2)
         assert key.extract_nonce(manifest2) == 1
@@ -124,8 +124,8 @@ class TestKey:
         # Key data sanity check
         assert len({key2.id_key, key2.enc_key, key2.enc_hmac_key}) == 3
         assert key2.chunk_seed != 0
-        chunk = Chunk(b'foo')
-        assert chunk == key2.decrypt(key.id_hash(chunk.data), key.encrypt(chunk))
+        chunk = b'foo'
+        assert chunk == key2.decrypt(key.id_hash(chunk), key.encrypt(chunk))
 
     def test_keyfile_nonce_rollback_protection(self, monkeypatch, keys_dir):
         monkeypatch.setenv('BORG_PASSPHRASE', 'test')
@@ -133,9 +133,9 @@ class TestKey:
         with open(os.path.join(get_security_dir(repository.id_str), 'nonce'), "w") as fd:
             fd.write("0000000000002000")
         key = KeyfileKey.create(repository, self.MockArgs())
-        data = key.encrypt(Chunk(b'ABC'))
+        data = key.encrypt(b'ABC')
         assert key.extract_nonce(data) == 0x2000
-        assert key.decrypt(None, data).data == b'ABC'
+        assert key.decrypt(None, data) == b'ABC'
 
     def test_keyfile_kfenv(self, tmpdir, monkeypatch):
         keyfile = tmpdir.join('keyfile')
@@ -144,8 +144,8 @@ class TestKey:
         assert not keyfile.exists()
         key = KeyfileKey.create(self.MockRepository(), self.MockArgs())
         assert keyfile.exists()
-        chunk = Chunk(b'ABC')
-        chunk_id = key.id_hash(chunk.data)
+        chunk = b'ABC'
+        chunk_id = key.id_hash(chunk)
         chunk_cdata = key.encrypt(chunk)
         key = KeyfileKey.detect(self.MockRepository(), chunk_cdata)
         assert chunk == key.decrypt(chunk_id, chunk_cdata)
@@ -158,7 +158,7 @@ class TestKey:
             fd.write(self.keyfile2_key_file)
         monkeypatch.setenv('BORG_PASSPHRASE', 'passphrase')
         key = KeyfileKey.detect(self.MockRepository(), self.keyfile2_cdata)
-        assert key.decrypt(self.keyfile2_id, self.keyfile2_cdata).data == b'payload'
+        assert key.decrypt(self.keyfile2_id, self.keyfile2_cdata) == b'payload'
 
     def test_keyfile2_kfenv(self, tmpdir, monkeypatch):
         keyfile = tmpdir.join('keyfile')
@@ -167,14 +167,14 @@ class TestKey:
         monkeypatch.setenv('BORG_KEY_FILE', str(keyfile))
         monkeypatch.setenv('BORG_PASSPHRASE', 'passphrase')
         key = KeyfileKey.detect(self.MockRepository(), self.keyfile2_cdata)
-        assert key.decrypt(self.keyfile2_id, self.keyfile2_cdata).data == b'payload'
+        assert key.decrypt(self.keyfile2_id, self.keyfile2_cdata) == b'payload'
 
     def test_keyfile_blake2(self, monkeypatch, keys_dir):
         with keys_dir.join('keyfile').open('w') as fd:
             fd.write(self.keyfile_blake2_key_file)
         monkeypatch.setenv('BORG_PASSPHRASE', 'passphrase')
         key = Blake2KeyfileKey.detect(self.MockRepository(), self.keyfile_blake2_cdata)
-        assert key.decrypt(self.keyfile_blake2_id, self.keyfile_blake2_cdata).data == b'payload'
+        assert key.decrypt(self.keyfile_blake2_id, self.keyfile_blake2_cdata) == b'payload'
 
     def test_passphrase(self, keys_dir, monkeypatch):
         monkeypatch.setenv('BORG_PASSPHRASE', 'test')
@@ -184,9 +184,9 @@ class TestKey:
         assert hexlify(key.enc_hmac_key) == b'b885a05d329a086627412a6142aaeb9f6c54ab7950f996dd65587251f6bc0901'
         assert hexlify(key.enc_key) == b'2ff3654c6daf7381dbbe718d2b20b4f1ea1e34caa6cc65f6bb3ac376b93fed2a'
         assert key.chunk_seed == -775740477
-        manifest = key.encrypt(Chunk(b'ABC'))
+        manifest = key.encrypt(b'ABC')
         assert key.extract_nonce(manifest) == 0
-        manifest2 = key.encrypt(Chunk(b'ABC'))
+        manifest2 = key.encrypt(b'ABC')
         assert manifest != manifest2
         assert key.decrypt(None, manifest) == key.decrypt(None, manifest2)
         assert key.extract_nonce(manifest2) == 1
@@ -197,9 +197,9 @@ class TestKey:
         assert key.enc_hmac_key == key2.enc_hmac_key
         assert key.enc_key == key2.enc_key
         assert key.chunk_seed == key2.chunk_seed
-        chunk = Chunk(b'foo')
-        assert hexlify(key.id_hash(chunk.data)) == b'818217cf07d37efad3860766dcdf1d21e401650fed2d76ed1d797d3aae925990'
-        assert chunk == key2.decrypt(key2.id_hash(chunk.data), key.encrypt(chunk))
+        chunk = b'foo'
+        assert hexlify(key.id_hash(chunk)) == b'818217cf07d37efad3860766dcdf1d21e401650fed2d76ed1d797d3aae925990'
+        assert chunk == key2.decrypt(key2.id_hash(chunk), key.encrypt(chunk))
 
     def _corrupt_byte(self, key, data, offset):
         data = bytearray(data)
@@ -224,7 +224,7 @@ class TestKey:
             key.decrypt(id, data)
 
     def test_decrypt_decompress(self, key):
-        plaintext = Chunk(b'123456789')
+        plaintext = b'123456789'
         encrypted = key.encrypt(plaintext)
         assert key.decrypt(None, encrypted, decompress=False) != plaintext
         assert key.decrypt(None, encrypted) == plaintext
@@ -244,10 +244,11 @@ class TestKey:
     def test_authenticated_encrypt(self, monkeypatch):
         monkeypatch.setenv('BORG_PASSPHRASE', 'test')
         key = AuthenticatedKey.create(self.MockRepository(), self.MockArgs())
-        plaintext = Chunk(b'123456789')
+        plaintext = b'123456789'
         authenticated = key.encrypt(plaintext)
-        # 0x06 is the key TYPE, 0x0000 identifies CNONE compression
-        assert authenticated == b'\x06\x00\x00' + plaintext.data
+        # 0x06 is the key TYPE, 0x0100 identifies LZ4 compression, 0x90 is part of LZ4 and means that an uncompressed
+        # block of length nine follows (the plaintext).
+        assert authenticated == b'\x06\x01\x00\x90' + plaintext
 
 
 class TestPassphrase: