Relanding 'update_payload: Add XZ compression support'

This patch adds support for checking a payload that has REPLACE_XZ
operations. REPLACE_XZ was added in minor version 3.

BUG=chromium:758792
TEST=unittests pass; paycheck.py with a xz generated payload pass;
CQ-DEPEND=CL:823234

Change-Id: I6ec8068e233f2d595fda93a985923d85c59f150e
Reviewed-on: https://chromium-review.googlesource.com/872124
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Sen Jiang <senj@chromium.org>

1 files changed, 21 insertions, 2 deletions

diff --git a/scripts/update_payload/applier.py b/scripts/update_payload/applier.py
index e470ac4e..8af89e79 100644
--- a/scripts/update_payload/applier.py
+++ b/scripts/update_payload/applier.py
@@ -18,6 +18,20 @@ import array
 import bz2
 import hashlib
 import itertools
+# Not everywhere we can have the lzma library so we ignore it if we didn't have
+# it because it is not going to be used. For example, 'cros flash' uses
+# devserver code which eventually loads this file, but the lzma library is not
+# included in the client test devices, and it is not necessary to do so. But
+# lzma is not used in 'cros flash' so it should be fine. Python 3.x include
+# lzma, but for backward compatibility with Python 2.7, backports-lzma is
+# needed.
+try:
+  import lzma
+except ImportError:
+  try:
+    from backports import lzma
+  except ImportError:
+    pass
 import os
 import shutil
 import subprocess
@@ -216,7 +230,7 @@ class PayloadApplier(object):
     self.truncate_to_expected_size = truncate_to_expected_size
 
   def _ApplyReplaceOperation(self, op, op_name, out_data, part_file, part_size):
-    """Applies a REPLACE{,_BZ} operation.
+    """Applies a REPLACE{,_BZ,_XZ} operation.
 
     Args:
       op: the operation object
@@ -235,6 +249,10 @@ class PayloadApplier(object):
     if op.type == common.OpType.REPLACE_BZ:
       out_data = bz2.decompress(out_data)
       data_length = len(out_data)
+    elif op.type == common.OpType.REPLACE_XZ:
+      # pylint: disable=no-member
+      out_data = lzma.decompress(out_data)
+      data_length = len(out_data)
 
     # Write data to blocks specified in dst extents.
     data_start = 0
@@ -508,7 +526,8 @@ class PayloadApplier(object):
       # Read data blob.
       data = self.payload.ReadDataBlob(op.data_offset, op.data_length)
 
-      if op.type in (common.OpType.REPLACE, common.OpType.REPLACE_BZ):
+      if op.type in (common.OpType.REPLACE, common.OpType.REPLACE_BZ,
+                     common.OpType.REPLACE_XZ):
         self._ApplyReplaceOperation(op, op_name, data, new_part_file, part_size)
       elif op.type == common.OpType.MOVE:
         self._ApplyMoveOperation(op, op_name, new_part_file)