Add filters to sq pki link list.

- Fixes #210.

src/cli/pki/link.rs

@@ -9,6 +9,7 @@ use crate::cli::types::UserIDDesignators;
 use crate::cli::types::userid_designator;
 use crate::cli::types::Expiration;
 use crate::cli::types::TrustAmount;
+use crate::cli::types::cert_designator::*;
 
 #[derive(Parser, Debug)]
 #[clap(
@@ -620,6 +621,11 @@ retracted.
     after_help = LIST_EXAMPLES,
 )]
 pub struct ListCommand {
+    #[command(flatten)]
+    pub certs: CertDesignators<CertUserIDEmailDomainGrepArgs,
+                               NoPrefix,
+                               OptionalValue>,
+
     #[clap(
         long = "ca",
         required = false,
@@ -649,6 +655,14 @@ with the email address alice@example.org.",
                 "sq", "pki", "link", "list",
             ],
         }),
+
+        Action::Example(Example {
+            comment: "List all links in the example.org domain.",
+            command: &[
+                "sq", "pki", "link", "list",
+                "--domain=example.org",
+            ],
+        }),
     ],
 };
 test_examples!(sq_pki_link_list, LIST_EXAMPLES);

src/commands/pki/link.rs

@@ -1,10 +1,13 @@
-use std::time::Duration;
+use std::{
+    sync::Arc,
+    time::Duration,
+};
 
 use sequoia_openpgp as openpgp;
 use openpgp::Result;
 
 use sequoia_cert_store as cert_store;
-use cert_store::Store;
+use cert_store::{LazyCert, Store};
 
 use crate::Sq;
 use crate::commands::active_certification;
@@ -179,7 +182,24 @@ pub fn list(sq: Sq, c: link::ListCommand)
 
     let cert_store = sq.cert_store_or_else()?;
     let mut dirty = false;
-    for cert in cert_store.certs() {
+
+    let (certs, errors) = if c.certs.is_empty() {
+        (cert_store.certs(), Vec::new())
+    } else {
+        let (c, e) = sq.resolve_certs(&c.certs, 0)?;
+        (Box::new(c.into_iter().map(|c| Arc::new(LazyCert::from(c))))
+         as Box<dyn Iterator<Item=Arc<LazyCert<'_>>>>,
+         e)
+    };
+
+    for error in errors.iter() {
+        crate::print_error_chain(error);
+    }
+    if ! errors.is_empty() {
+        return Err(anyhow::anyhow!("Failed to resolve certificates"));
+    }
+
+    for cert in certs {
         let cert = if let Ok(cert) = cert.to_cert() {
             cert
         } else {
@@ -206,6 +226,7 @@ pub fn list(sq: Sq, c: link::ListCommand)
                 .unwrap_or((0, sequoia_wot::FULLY_TRUSTED as u8));
 
             if c.ca && depth == 0 {
+                // Only show CAs.
                 continue;
             }