set-verity-state: Simplify args parsing logic

Bug: 241688845
Test: adb [disable|enable]-verity
Test: adb shell set-verity-state [0|1]
Change-Id: I751e6b79c690d986a9cde7fc94c81c5b3ce884f0
diff --git a/set-verity-state/set-verity-state.cpp b/set-verity-state/set-verity-state.cpp
index e132263..d8e3d31 100644
--- a/set-verity-state/set-verity-state.cpp
+++ b/set-verity-state/set-verity-state.cpp
@@ -24,6 +24,8 @@
 #include <fs_mgr_overlayfs.h>
 #include <log/log_properties.h>
 
+using namespace std::string_literals;
+
 #ifdef ALLOW_DISABLE_VERITY
 static const bool kAllowDisableVerity = true;
 #else
@@ -95,32 +97,19 @@
     LOG(FATAL) << "set-verity-state called with empty argv";
   }
 
-  std::optional<bool> enable_opt;
+  bool enable = false;
   std::string procname = android::base::Basename(argv[0]);
   if (procname == "enable-verity") {
-    enable_opt = true;
+    enable = true;
   } else if (procname == "disable-verity") {
-    enable_opt = false;
+    enable = false;
+  } else if (argc == 2 && (argv[1] == "1"s || argv[1] == "0"s)) {
+    enable = (argv[1] == "1"s);
+  } else {
+    printf("usage: %s [1|0]\n", argv[0]);
+    return 1;
   }
 
-  if (!enable_opt.has_value()) {
-    if (argc != 2) {
-      printf("usage: %s [1|0]\n", argv[0]);
-      return 1;
-    }
-
-    if (strcmp(argv[1], "1") == 0) {
-      enable_opt = true;
-    } else if (strcmp(argv[1], "0") == 0) {
-      enable_opt = false;
-    } else {
-      printf("usage: %s [1|0]\n", argv[0]);
-      return 1;
-    }
-  }
-
-  bool enable = enable_opt.value();
-
   // Figure out if we're using VB1.0 or VB2.0 (aka AVB) - by
   // contract, androidboot.vbmeta.digest is set by the bootloader
   // when using AVB).