add the functions for multi-stage packages to updater

In order to support multi-stage recovery packages, we add the
set_stage() and get_stage() functions, which store a short string
somewhere it can be accessed across invocations of recovery.  We also
add reboot_now() which updater can invoke to immediately reboot the
device, without doing normal recovery cleanup.  (It can also choose
whether to boot off the boot or recovery partition.)

If the stage string is of the form "#/#", recovery's UI will be
augmented with a simple indicator of what stage you're in, so it
doesn't look like a reboot loop.

Change-Id: I62f7ff0bc802b549c9bcf3cc154a6bad99f94603

1 files changed, 2 insertions, 0 deletions

diff --git a/ui.h b/ui.h
index 6c8987a..0757260 100644
--- a/ui.h
+++ b/ui.h
@@ -30,6 +30,8 @@ class RecoveryUI {
 
     // Initialize the object; called before anything else.
     virtual void Init();
+    // Show a stage indicator.  Call immediately after Init().
+    virtual void SetStage(int current, int max) { }
 
     // After calling Init(), you can tell the UI what locale it is operating in.
     virtual void SetLocale(const char* locale) { }