Fix error if ramdisk is minigzip compression

This change intends to fix if ramdisk is not "lz4" compression.
Legacy is "minigzip" compression.

If not lz4, the following error will happen when exec build_super_image.py:
  Unable to get boot image build props: Failed to run command '['lz4', '-d', '/tmp/boot_omdZZ8.img/ramdisk', '/tmp/boot_omdZZ8.img/uncompressed_ramdisk']' (exit code 44):
  Error 44 : Unrecognized header : file cannot be decoded

Change-Id: I71248387bbeecbf184e0c24e6346c235d728518e
Signed-off-by: jiajia tang <tangjiajia@xiaomi.com>

tools/releasetools/Android.bp

@@ -133,6 +133,7 @@ python_defaults {
     required: [
         "brillo_update_payload",
         "checkvintf",
+        "minigzip",
         "lz4",
         "toybox",
         "unpack_bootimg",

tools/releasetools/common.py

@@ -651,6 +651,9 @@ def ExtractFromInputFile(input_file, fn):
       raise KeyError(fn)
     return file
 
+class RamdiskFormat(object):
+  LZ4 = 1
+  GZ = 2
 
 def LoadInfoDict(input_file, repacking=False):
   """Loads the key/value pairs from the given input target_files.
@@ -753,13 +756,17 @@ def LoadInfoDict(input_file, repacking=False):
 
   # Load recovery fstab if applicable.
   d["fstab"] = _FindAndLoadRecoveryFstab(d, input_file, read_helper)
+  if d.get('lz4_ramdisks') == 'true':
+    ramdisk_format = RamdiskFormat.LZ4
+  else:
+    ramdisk_format = RamdiskFormat.GZ
 
   # Tries to load the build props for all partitions with care_map, including
   # system and vendor.
   for partition in PARTITIONS_WITH_BUILD_PROP:
     partition_prop = "{}.build.prop".format(partition)
     d[partition_prop] = PartitionBuildProps.FromInputFile(
-        input_file, partition)
+        input_file, partition, ramdisk_format=ramdisk_format)
   d["build.prop"] = d["system.build.prop"]
 
   # Set up the salt (based on fingerprint) that will be used when adding AVB
@@ -818,6 +825,9 @@ class PartitionBuildProps(object):
     placeholder_values: A dict of runtime variables' values to replace the
         placeholders in the build.prop file. We expect exactly one value for
         each of the variables.
+    ramdisk_format: If name is "boot", the format of ramdisk inside the
+        boot image. Otherwise, its value is ignored.
+        Use lz4 to decompress by default. If its value is gzip, use minigzip.
   """
 
   def __init__(self, input_file, name, placeholder_values=None):
@@ -840,11 +850,11 @@ class PartitionBuildProps(object):
     return props
 
   @staticmethod
-  def FromInputFile(input_file, name, placeholder_values=None):
+  def FromInputFile(input_file, name, placeholder_values=None, ramdisk_format=RamdiskFormat.LZ4):
     """Loads the build.prop file and builds the attributes."""
 
     if name == "boot":
-      data = PartitionBuildProps._ReadBootPropFile(input_file)
+      data = PartitionBuildProps._ReadBootPropFile(input_file, ramdisk_format=ramdisk_format)
     else:
       data = PartitionBuildProps._ReadPartitionPropFile(input_file, name)
 
@@ -853,7 +863,7 @@ class PartitionBuildProps(object):
     return props
 
   @staticmethod
-  def _ReadBootPropFile(input_file):
+  def _ReadBootPropFile(input_file, ramdisk_format):
     """
     Read build.prop for boot image from input_file.
     Return empty string if not found.
@@ -863,7 +873,7 @@ class PartitionBuildProps(object):
     except KeyError:
       logger.warning('Failed to read IMAGES/boot.img')
       return ''
-    prop_file = GetBootImageBuildProp(boot_img)
+    prop_file = GetBootImageBuildProp(boot_img, ramdisk_format=ramdisk_format)
     if prop_file is None:
       return ''
     with open(prop_file, "r") as f:
@@ -3661,12 +3671,12 @@ class DynamicPartitionsDifference(object):
         append('move %s %s' % (p, u.tgt_group))
 
 
-def GetBootImageBuildProp(boot_img):
+def GetBootImageBuildProp(boot_img, ramdisk_format=RamdiskFormat.LZ4):
   """
   Get build.prop from ramdisk within the boot image
 
   Args:
-    boot_img: the boot image file. Ramdisk must be compressed with lz4 format.
+    boot_img: the boot image file. Ramdisk must be compressed with lz4 or minigzip format.
 
   Return:
     An extracted file that stores properties in the boot image.
@@ -3679,7 +3689,16 @@ def GetBootImageBuildProp(boot_img):
       logger.warning('Unable to get boot image timestamp: no ramdisk in boot')
       return None
     uncompressed_ramdisk = os.path.join(tmp_dir, 'uncompressed_ramdisk')
-    RunAndCheckOutput(['lz4', '-d', ramdisk, uncompressed_ramdisk])
+    if ramdisk_format == RamdiskFormat.LZ4:
+      RunAndCheckOutput(['lz4', '-d', ramdisk, uncompressed_ramdisk])
+    elif ramdisk_format == RamdiskFormat.GZ:
+      with open(ramdisk, 'rb') as input_stream:
+        with open(uncompressed_ramdisk, 'wb') as output_stream:
+          p2 = Run(['minigzip', '-d'], stdin=input_stream.fileno(), stdout=output_stream.fileno())
+          p2.wait()
+    else:
+      logger.error('Only support lz4 or minigzip ramdisk format.')
+      return None
 
     abs_uncompressed_ramdisk = os.path.abspath(uncompressed_ramdisk)
     extracted_ramdisk = MakeTempDir('extracted_ramdisk')