Prepare for clap 4.

Bug: 260823636
Test: atest vm.test encryptedstore.test apkdmverity.test open_then_run.test ZipFuseTest
Change-Id: Iba2c4c317e7e42fc99362caf41ab083b4fc4a8db
diff --git a/encryptedstore/src/main.rs b/encryptedstore/src/main.rs
index 7140ae2..888485b 100644
--- a/encryptedstore/src/main.rs
+++ b/encryptedstore/src/main.rs
@@ -19,9 +19,8 @@
 //! It uses dm_rust lib.
 
 use anyhow::{ensure, Context, Result};
-use clap::{arg, App};
-use dm::crypt::CipherType;
-use dm::util;
+use clap::arg;
+use dm::{crypt::CipherType, util};
 use log::info;
 use std::ffi::CString;
 use std::fs::{create_dir_all, OpenOptions};
@@ -42,18 +41,11 @@
     );
     info!("Starting encryptedstore binary");
 
-    let matches = App::new("encryptedstore")
-        .args(&[
-            arg!(--blkdevice <FILE> "the block device backing the encrypted storage")
-                .required(true),
-            arg!(--key <KEY> "key (in hex) equivalent to 32 bytes)").required(true),
-            arg!(--mountpoint <MOUNTPOINT> "mount point for the storage").required(true),
-        ])
-        .get_matches();
+    let matches = clap_command().get_matches();
 
-    let blkdevice = Path::new(matches.value_of("blkdevice").unwrap());
-    let key = matches.value_of("key").unwrap();
-    let mountpoint = Path::new(matches.value_of("mountpoint").unwrap());
+    let blkdevice = Path::new(matches.get_one::<String>("blkdevice").unwrap());
+    let key = matches.get_one::<String>("key").unwrap();
+    let mountpoint = Path::new(matches.get_one::<String>("mountpoint").unwrap());
     encryptedstore_init(blkdevice, key, mountpoint).context(format!(
         "Unable to initialize encryptedstore on {:?} & mount at {:?}",
         blkdevice, mountpoint
@@ -61,6 +53,14 @@
     Ok(())
 }
 
+fn clap_command() -> clap::Command {
+    clap::Command::new("encryptedstore").args(&[
+        arg!(--blkdevice <FILE> "the block device backing the encrypted storage").required(true),
+        arg!(--key <KEY> "key (in hex) equivalent to 32 bytes)").required(true),
+        arg!(--mountpoint <MOUNTPOINT> "mount point for the storage").required(true),
+    ])
+}
+
 fn encryptedstore_init(blkdevice: &Path, key: &str, mountpoint: &Path) -> Result<()> {
     ensure!(
         std::fs::metadata(&blkdevice)
@@ -160,3 +160,14 @@
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn verify_command() {
+        // Check that the command parsing has been configured in a valid way.
+        clap_command().debug_assert();
+    }
+}