Port sq pki path to the user ID designator framework.

- Port `sq pki path` to the user ID designator framework.
    See #434.

  - This change adds two new additional arguments, `--email` and
    `--name`.

NEWS

@@ -63,6 +63,8 @@
    - `sq pki path` previously interpreted the last positional argument
      as the user ID to authenticate.  Make it a named argument
      instead, `--userid`.
+   - Add `sq pki path --email` and `sq pki path --name` as additional
+     ways to specify the user ID to authenticate.
 
 * Changes in 0.39.0
 ** Notable changes

src/cli/pki/path.rs

@@ -2,13 +2,15 @@ use clap::Parser;
 
 use sequoia_openpgp as openpgp;
 use openpgp::KeyHandle;
-use openpgp::packet::UserID;
 
 use crate::cli::examples;
 use examples::Action;
 use examples::Actions;
 use examples::Example;
 
+use crate::cli::types::UserIDDesignators;
+use crate::cli::types::userid_designator;
+
 use super::CertificationNetworkArg;
 use super::RequiredTrustAmountArg;
 
@@ -45,12 +47,10 @@ the specified user ID.
     )]
     pub path: Vec<KeyHandle>,
 
-    #[clap(
-        long = "userid",
-        value_name = "USERID",
-        help = "The user ID to authenticate",
-    )]
-    pub userid: UserID,
+    #[command(flatten)]
+    pub userids: UserIDDesignators<
+        userid_designator::AnyUserIDEmailNameArgs,
+        userid_designator::OneValue>,
 
     #[command(flatten)]
     pub certification_network: CertificationNetworkArg,

src/cli/types/userid_designator.rs

@@ -63,6 +63,11 @@ pub type ExistingUserIDEmailNameArgs
 pub type AnyUserIDEmailArgs
     = <AnyUserIDArg as std::ops::BitOr<AnyEmailArg>>::Output;
 
+/// Enables --userid, --email, and --name (but not --add-userid,
+/// --add-email, or --add-name).
+pub type AnyUserIDEmailNameArgs
+    = <AnyUserIDEmailArgs as std::ops::BitOr<AnyNameArg>>::Output;
+
 /// Enables --add-userid, and --add-email (but not --userid, --email,
 /// --name, or --add-name).
 pub type AddUserIDEmailArgs
@@ -192,6 +197,27 @@ impl UserIDDesignator {
             userid,
         }
     }
+
+    /// Resolves to the designated user ID.
+    ///
+    /// If an email or a name, first converts them to a user ID in the
+    /// usual manner.
+    pub fn resolve_to_self(&self) -> ResolvedUserID {
+        use UserIDDesignator::*;
+        let userid = match self {
+            UserID(userid) | AnyUserID(userid) | AddUserID(userid) =>
+                openpgp::packet::UserID::from(&userid[..]),
+            Email(email) | AnyEmail(email) | AddEmail(email) =>
+                openpgp::packet::UserID::from(&format!("<{}>", email)[..]),
+            Name(name) | AnyName(name) | AddName(name) =>
+                openpgp::packet::UserID::from(&name[..]),
+        };
+
+        ResolvedUserID {
+            designator: Some(self.clone()),
+            userid,
+        }
+    }
 }
 
 /// A data structure that can be flattened into a clap `Command`, and
@@ -237,6 +263,11 @@ impl<Arguments, Options> UserIDDesignators<Arguments, Options> {
         self.designators.is_empty()
     }
 
+    /// Like `Vec::len`.
+    pub fn len(&self) -> usize {
+        self.designators.len()
+    }
+
     /// Iterates over the user ID designators.
     pub fn iter(&self) -> impl Iterator<Item=&UserIDDesignator> {
         self.designators.iter()

src/commands/pki/path.rs

@@ -16,9 +16,25 @@ pub fn path(sq: Sq, c: Command)
     -> Result<()>
 {
     let Command {
-        certification_network, trust_amount, path, userid,
+        certification_network, trust_amount, path, userids,
     } = c;
 
+    assert_eq!(userids.len(), 1, "guaranteed by clap");
+
+    let target = path.last().expect("guaranteed by clap");
+    let mut userid = None;
+    if let Ok(cert) = sq.lookup_one(target, None, false) {
+        if let Ok(vc) = cert.with_policy(sq.policy, sq.time) {
+            if let Ok(userids) = userids.resolve(&vc) {
+                assert_eq!(userids.len(), 1);
+                userid = Some(userids.into_iter().next().unwrap());
+            }
+        }
+    }
+    let userid = userid.unwrap_or_else(|| {
+        userids.iter().next().unwrap().resolve_to_self()
+    });
+
     // Build the network.
     let cert_store = match sq.cert_store() {
         Ok(Some(cert_store)) => cert_store,
@@ -41,7 +57,7 @@ pub fn path(sq: Sq, c: Command)
 
     assert!(path.len() > 0, "guaranteed by clap");
 
-    let r = q.lint_path(&path, &userid, required_amount, sq.policy);
+    let r = q.lint_path(&path, userid.userid(), required_amount, sq.policy);
 
     let target_kh = path.last().expect("have one");
 
@@ -49,11 +65,11 @@ pub fn path(sq: Sq, c: Command)
         Ok(path) => {
             print_path_header(
                 target_kh,
-                &userid,
+                userid.userid(),
                 path.amount(),
                 required_amount,
             );
-            print_path(&path, &userid, "  ")?;
+            print_path(&path, userid.userid(), "  ")?;
 
             let trust_amount = path.amount();
             if trust_amount >= required_amount {
@@ -65,7 +81,7 @@ pub fn path(sq: Sq, c: Command)
         Err(err) => {
             print_path_header(
                 target_kh,
-                &userid,
+                userid.userid(),
                 0,
                 required_amount,
             );