extract: if --stdout is given, write all extracted binary data to stdout

attic/archive.py

@@ -230,11 +230,14 @@ class Archive:
         cache.rollback()
         return stats
 
-    def extract_item(self, item, restore_attrs=True, dry_run=False):
-        if dry_run:
+    def extract_item(self, item, restore_attrs=True, dry_run=False, stdout=False):
+        if dry_run or stdout:
             if b'chunks' in item:
-                for _ in self.pipeline.fetch_many([c[0] for c in item[b'chunks']], is_preloaded=True):
-                    pass
+                for data in self.pipeline.fetch_many([c[0] for c in item[b'chunks']], is_preloaded=True):
+                    if stdout:
+                        sys.stdout.buffer.write(data)
+                if stdout:
+                    sys.stdout.buffer.flush()
             return
 
         dest = self.cwd

attic/archiver.py

@@ -202,6 +202,7 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
                           numeric_owner=args.numeric_owner)
         patterns = adjust_patterns(args.paths, args.excludes)
         dry_run = args.dry_run
+        stdout = args.stdout
         strip_components = args.strip_components
         dirs = []
         for item in archive.iter_items(lambda item: not exclude_path(item[b'path'], patterns), preload=True):
@@ -212,7 +213,7 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
                     continue
             if not args.dry_run:
                 while dirs and not item[b'path'].startswith(dirs[-1][b'path']):
-                    archive.extract_item(dirs.pop(-1))
+                    archive.extract_item(dirs.pop(-1), stdout=stdout)
             self.print_verbose(remove_surrogates(orig_path))
             try:
                 if dry_run:
@@ -222,7 +223,7 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
                         dirs.append(item)
                         archive.extract_item(item, restore_attrs=False)
                     else:
-                        archive.extract_item(item)
+                        archive.extract_item(item, stdout=stdout)
             except IOError as e:
                 self.print_error('%s: %s', remove_surrogates(orig_path), e)
 
@@ -592,6 +593,9 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
         subparser.add_argument('--strip-components', dest='strip_components',
                                type=int, default=0, metavar='NUMBER',
                                help='Remove the specified number of leading path elements. Pathnames with fewer elements will be silently skipped.')
+        subparser.add_argument('--stdout', dest='stdout',
+                               action='store_true', default=False,
+                               help='write all extracted data to stdout')
         subparser.add_argument('archive', metavar='ARCHIVE',
                                type=location_validator(archive=True),
                                help='archive to extract')