update_engine: Add UMA stats for rollback
Adding the following UMA stats:
- UpdateEngine.Check.TargetVersion: first section of the Chrome OS
target version set by device policy. Sent during update checks if
target version policy is set.
- UpdateEngine.Check.RollbackTargetVersion: first section of the
Chrome OS target version if rollback is also allowed. Sent during
update checks if both policies are set.
- UpdateEngine.EnterpriseRollback.Success: first section of the
Chrome OS version to which rollback succeeded. Sent after
successful installation of the rollback image.
- UpdateEngine.EnterpriseRollback.Failure: first section of the
Chrome OS version to which rollback failed. Sent after
installation of the rollback image failed.
Chromium CL of the new histograms: crrev.com/c/1069129
BUG=chromium:843622
TEST='cros_run_unit_tests --board=caroline --packages update_engine'
Change-Id: I0b76fa286498ae0a1830a90034734ed9aa5efd3d
Reviewed-on: https://chromium-review.googlesource.com/1062033
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Marton Hunyady <hunyadym@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Jesse Doherty <jwd@chromium.org>
diff --git a/common/utils.h b/common/utils.h
index c102a16..8db0cf8 100644
--- a/common/utils.h
+++ b/common/utils.h
@@ -317,6 +317,11 @@
// reboot. Returns whether it succeeded getting the boot_id.
bool GetBootId(std::string* boot_id);
+// Returns the integer value of the first section of |version|. E.g. for
+// "10575.39." returns 10575. Returns 0 if |version| is empty, returns -1 if
+// first section of |version| is invalid (e.g. not a number).
+int VersionPrefix(const std::string& version);
+
} // namespace utils