Use add_slot_suffix function in edify script

Whenever a device is retrieved from fstab, wrap it with
add_slot_suffix() if it has slotselect option.

Test: change fstab (changes boot image, which is a static partition),
      change system partition (a dynamic partition),
      generate incremental OTA with --force_non_ab and apply it on
      cuttlefish
Bug: 153581609
Change-Id: Id3f8e4425b65176baf1b0ff1ee07ab3d820a3a7f

tools/releasetools/common.py

@@ -2493,11 +2493,12 @@ class BlockDifference(object):
       self.device = 'map_partition("%s")' % partition
     else:
       if OPTIONS.source_info_dict is None:
-        _, device_path = GetTypeAndDevice("/" + partition, OPTIONS.info_dict)
+        _, device_expr = GetTypeAndDeviceExpr("/" + partition,
+                                              OPTIONS.info_dict)
       else:
-        _, device_path = GetTypeAndDevice("/" + partition,
-                                          OPTIONS.source_info_dict)
-      self.device = '"%s"' % device_path
+        _, device_expr = GetTypeAndDeviceExpr("/" + partition,
+                                              OPTIONS.source_info_dict)
+      self.device = device_expr
 
   @property
   def required_cache(self):
@@ -2729,16 +2730,51 @@ PARTITION_TYPES = {
     "squashfs": "EMMC"
 }
 
-
-def GetTypeAndDevice(mount_point, info):
+def GetTypeAndDevice(mount_point, info, check_no_slot=True):
+  """
+  Use GetTypeAndDeviceExpr whenever possible. This function is kept for
+  backwards compatibility. It aborts if the fstab entry has slotselect option
+  (unless check_no_slot is explicitly set to False).
+  """
   fstab = info["fstab"]
   if fstab:
+    if check_no_slot:
+      assert not fstab[mount_point].slotselect, \
+             "Use GetTypeAndDeviceExpr instead"
     return (PARTITION_TYPES[fstab[mount_point].fs_type],
             fstab[mount_point].device)
   else:
     raise KeyError
 
 
+def GetTypeAndDeviceExpr(mount_point, info):
+  """
+  Return the filesystem of the partition, and an edify expression that evaluates
+  to the device at runtime.
+  """
+  fstab = info["fstab"]
+  if fstab:
+    p = fstab[mount_point]
+    device_expr = '"%s"' % fstab[mount_point].device
+    if p.slotselect:
+      device_expr = 'add_slot_suffix(%s)' % device_expr
+    return (PARTITION_TYPES[fstab[mount_point].fs_type], device_expr)
+  else:
+    raise KeyError
+
+
+def GetEntryForDevice(fstab, device):
+  """
+  Returns:
+    The first entry in fstab whose device is the given value.
+  """
+  if not fstab:
+    return None
+  for mount_point in fstab:
+    if fstab[mount_point].device == device:
+      return fstab[mount_point]
+  return None
+
 def ParseCertificate(data):
   """Parses and converts a PEM-encoded certificate into DER-encoded.
 
@@ -2863,8 +2899,10 @@ def MakeRecoveryPatch(input_dir, output_sink, recovery_img, boot_img,
   try:
     # The following GetTypeAndDevice()s need to use the path in the target
     # info_dict instead of source_info_dict.
-    boot_type, boot_device = GetTypeAndDevice("/boot", info_dict)
-    recovery_type, recovery_device = GetTypeAndDevice("/recovery", info_dict)
+    boot_type, boot_device = GetTypeAndDevice("/boot", info_dict,
+                                              check_no_slot=False)
+    recovery_type, recovery_device = GetTypeAndDevice("/recovery", info_dict,
+                                                      check_no_slot=False)
   except KeyError:
     return
 
@@ -2906,8 +2944,8 @@ fi
        'recovery_size': recovery_img.size,
        'recovery_sha1': recovery_img.sha1,
        'boot_type': boot_type,
-       'boot_device': boot_device,
-       'recovery_type': recovery_type,
+       'boot_device': boot_device + '$(getprop ro.boot.slot_suffix)',
+       'recovery_type': recovery_type + '$(getprop ro.boot.slot_suffix)',
        'recovery_device': recovery_device,
        'bonus_args': bonus_args}