Refactor: Use PathBuf instead of String for file related CLI options

- Replace `Option<String>` and `Vec<String>` based CLI options dealing
  with files with `Option<PathBuf>` and `Vec<PathBuf>` based ones
  (respectively).
  This allows us to unify the use of input and output facilities using
  globally available CLI options while ensuring (cross-platform) type
  safety.

src/commands/import.rs

@@ -1,4 +1,5 @@
 use std::borrow::Cow;
+use std::path::PathBuf;
 
 use sequoia_openpgp as openpgp;
 use openpgp::{
@@ -22,7 +23,7 @@ pub fn dispatch<'store>(mut config: Config<'store>, cmd: import::Command)
     -> Result<()>
 {
     let inputs = if cmd.input.is_empty() {
-        vec![ "-".to_string() ]
+        vec![ PathBuf::from("-") ]
     } else {
         cmd.input
     };
@@ -32,7 +33,7 @@ pub fn dispatch<'store>(mut config: Config<'store>, cmd: import::Command)
     let inner = || -> Result<()> {
         for input in inputs.into_iter() {
             let input = open_or_stdin(
-                if input == "-" { None } else { Some(&input) })?;
+                if input == PathBuf::from("-") { None } else { Some(&input) })?;
             let raw_certs = RawCertParser::from_reader(input)?;
 
             let cert_store = config.cert_store_mut_or_else()?;

src/commands/inspect.rs

@@ -1,6 +1,5 @@
 use std::convert::TryFrom;
 use std::io::{self, Read};
-use std::path::Path;
 use std::time::{Duration, SystemTime};
 
 use anyhow::Context;
@@ -40,7 +39,11 @@ pub fn inspect(mut config: Config, c: inspect::Command)
     let print_certifications = c.certifications;
 
     let input = c.input.as_deref();
-    let input_name = input.unwrap_or("-");
+    let input_name = if let Some(input) = c.input.as_ref() {
+        format!("{}", input.display())
+    } else {
+        "-".to_string()
+    };
     write!(output, "{}: ", input_name)?;
 
     let mut type_called = false;  // Did we print the type yet?
@@ -53,11 +56,12 @@ pub fn inspect(mut config: Config, c: inspect::Command)
 
     let mut bytes: Vec<u8> = Vec::new();
     let mut ppr = if c.cert.is_empty() {
-        if let Some(input) = input.as_ref() {
+        if let Some(input) = input {
-            if ! Path::new(input).exists() && input.parse::<KeyHandle>().is_ok() {
+            if ! input.exists() &&
+                format!("{}", input.display()).parse::<KeyHandle>().is_ok() {
                 eprintln!("The file {} does not exist, \
                            did you mean \"sq inspect --cert {}\"?",
-                          input, input);
+                          input.display(), input.display());
             }
         }
 

src/commands/key/generate.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use chrono::DateTime;
 use chrono::Utc;
 
@@ -111,33 +113,30 @@ pub fn generate(
         }
     }
 
+    if command.export.is_none() {
+        return Err(anyhow::anyhow!(
+            "Saving generated key to the store isn't implemented yet."
+        ));
+    }
+
     // Generate the key
     let (cert, rev) = builder.generate()?;
 
     // Export
-    if command.export.is_some() {
+    if let Some(key_path) = command.export.as_ref() {
-        let (key_path, rev_path) =
+        if &format!("{}", key_path.display()) == "-"
-            match (command.export.as_deref(), command.rev_cert.as_deref()) {
+            && command.rev_cert.is_none()
-                (Some("-"), Some("-")) => ("-".to_string(), "-".to_string()),
+        {
-                (Some("-"), Some(ref rp)) => ("-".to_string(), rp.to_string()),
+            return Err(anyhow::anyhow!(
-                (Some("-"), None) => {
+                "Missing arguments: --rev-cert is mandatory if --export is '-'."
-                    return Err(anyhow::anyhow!(
+            ))
-                        "Missing arguments: --rev-cert is mandatory \
+        }
-                                     if --export is '-'."
+
-                    ))
+        let rev_path = if command.rev_cert.is_some() {
-                }
+            command.rev_cert
-                (Some(ref kp), None) => (kp.to_string(), format!("{}.rev", kp)),
+        } else {
-                (Some(ref kp), Some("-")) => (kp.to_string(), "-".to_string()),
+            Some(PathBuf::from(format!("{}.rev", key_path.display())))
-                (Some(ref kp), Some(ref rp)) => {
+        };
-                    (kp.to_string(), rp.to_string())
-                }
-                _ => {
-                    return Err(anyhow::anyhow!(
-                        "Conflicting arguments --rev-cert and \
-                                     --export"
-                    ))
-                }
-            };
 
         let headers = cert.armor_headers();
 
@@ -148,7 +147,7 @@ pub fn generate(
                 .map(|value| ("Comment", value.as_str()))
                 .collect();
 
-            let w = config.create_or_stdout_safe(Some(&key_path))?;
+            let w = config.create_or_stdout_safe(Some(key_path))?;
             let mut w = Writer::with_headers(w, Kind::SecretKey, headers)?;
             cert.as_tsk().serialize(&mut w)?;
             w.finalize()?;
@@ -162,16 +161,11 @@ pub fn generate(
                 .collect();
             headers.insert(0, ("Comment", "Revocation certificate for"));
 
-            let w = config.create_or_stdout_safe(Some(&rev_path))?;
+            let w = config.create_or_stdout_safe(rev_path.as_deref())?;
             let mut w = Writer::with_headers(w, Kind::Signature, headers)?;
             Packet::Signature(rev).serialize(&mut w)?;
             w.finalize()?;
         }
-    } else {
-        return Err(anyhow::anyhow!(
-            "Saving generated key to the store isn't implemented \
-                         yet."
-        ));
     }
 
     Ok(())

src/commands/keyring.rs

@@ -5,6 +5,7 @@ use std::{
     io,
     path::PathBuf,
 };
+use std::ops::Deref;
 use anyhow::Context;
 
 use sequoia_openpgp as openpgp;
@@ -162,7 +163,7 @@ pub fn dispatch(config: Config, c: keyring::Command) -> Result<()> {
                 config.create_or_stdout_pgp(c.output.as_deref(),
                                             c.binary,
                                             armor::Kind::PublicKey)?;
-            merge(c.input, &mut output)?;
+            merge(&c.input, &mut output)?;
             output.finalize()
         },
         List(c) => {
@@ -190,16 +191,16 @@ pub fn dispatch(config: Config, c: keyring::Command) -> Result<()> {
 }
 
 /// Joins certificates and keyrings into a keyring, applying a filter.
-fn filter<F>(inputs: &[String], output: &mut dyn io::Write,
+fn filter<F>(inputs: &[PathBuf], output: &mut dyn io::Write,
              mut filter: F, to_certificate: bool)
              -> Result<()>
     where F: FnMut(Cert) -> Option<Cert>,
 {
     if !inputs.is_empty() {
         for name in inputs {
-            for cert in CertParser::from_file(name)? {
+            for cert in CertParser::from_file(name.deref())? {
                 let cert = cert.context(
-                    format!("Malformed certificate in keyring {:?}", name))?;
+                    format!("Malformed certificate in keyring {:?}", name.display()))?;
                 if let Some(cert) = filter(cert) {
                     if to_certificate {
                         cert.serialize(output)?;
@@ -318,7 +319,7 @@ fn split(input: &mut (dyn io::Read + Sync + Send), prefix: &str, binary: bool)
 }
 
 /// Merge multiple keyrings.
-fn merge(inputs: Vec<String>, output: &mut dyn io::Write)
+fn merge(inputs: &[PathBuf], output: &mut dyn io::Write)
              -> Result<()>
 {
     let mut certs: HashMap<Fingerprint, Option<Cert>> = HashMap::new();

src/commands/mod.rs

@@ -4,6 +4,7 @@ use std::cmp::Ordering;
 use std::collections::{HashMap, HashSet};
 use std::fs::File;
 use std::io::{self, Write};
+use std::path::Path;
 use std::time::SystemTime;
 
 use sequoia_net::pks;
@@ -962,7 +963,7 @@ pub fn join(config: Config, c: packet::JoinCommand) -> Result<()> {
     /// OUTPUT.
     fn copy(config: &Config,
             mut ppr: PacketParserResult,
-            output: Option<&str>,
+            output: Option<&Path>,
             sink: &mut Option<Message>)
             -> Result<()> {
         while let PacketParserResult::Some(pp) = ppr {

src/commands/revoke.rs

@@ -1,4 +1,5 @@
 use anyhow::Context as _;
+use std::path::Path;
 use std::time::SystemTime;
 
 use sequoia_openpgp as openpgp;
@@ -145,7 +146,7 @@ pub fn revoke_userid(config: Config, c: revoke::UseridCommand) -> Result<()> {
 }
 
 /// Parse the cert from input and ensure it is only one cert.
-fn read_cert(input: Option<&str>) -> Result<Cert> {
+fn read_cert(input: Option<&Path>) -> Result<Cert> {
     let input = open_or_stdin(input)?;
 
     let cert = CertParser::from_reader(input)?.collect::<Vec<_>>();
@@ -159,7 +160,7 @@ fn read_cert(input: Option<&str>) -> Result<Cert> {
 }
 
 /// Parse the secret key and ensure it is at most one.
-fn read_secret(skf: Option<&str>) -> Result<Option<Cert>> {
+fn read_secret(skf: Option<&Path>) -> Result<Option<Cert>> {
     let secret = load_certs(skf.into_iter())?;
     if secret.len() > 1 {
         Err(anyhow::anyhow!("Multiple secret keys provided."))?;

src/commands/sign.rs

@@ -1,6 +1,7 @@
 use anyhow::Context as _;
 use std::fs;
 use std::io;
+use std::path::Path;
 use std::path::PathBuf;
 use std::time::SystemTime;
 use tempfile::NamedTempFile;
@@ -27,7 +28,7 @@ pub struct SignOpts<'a, 'certdb> {
     pub config: Config<'certdb>,
     pub private_key_store: Option<&'a str>,
     pub input: &'a mut (dyn io::Read + Sync + Send),
-    pub output_path: Option<&'a str>,
+    pub output_path: Option<&'a Path>,
     pub secrets: Vec<openpgp::Cert>,
     pub detached: bool,
     pub binary: bool,

src/sq.rs

@@ -71,19 +71,19 @@ pub mod output;
 pub use output::{wkd::WkdUrlVariant, Model, OutputFormat, OutputVersion};
 
 
-fn open_or_stdin(f: Option<&str>)
+fn open_or_stdin(f: Option<&Path>)
                  -> Result<Box<dyn BufferedReader<()>>> {
     match f {
         Some(f) => Ok(Box::new(
             File::open(f)
-                .with_context(|| format!("Failed to open {}", f))?)),
+                .with_context(|| format!("Failed to open {}", f.display()))?)),
         None => Ok(Box::new(Generic::new(io::stdin(), None))),
     }
 }
 
 /// Loads one TSK from every given file.
 fn load_keys<'a, I>(files: I) -> openpgp::Result<Vec<Cert>>
-    where I: Iterator<Item=&'a str>
+    where I: Iterator<Item=&'a Path>
 {
     let mut certs = vec![];
     for f in files {
@@ -100,7 +100,7 @@ fn load_keys<'a, I>(files: I) -> openpgp::Result<Vec<Cert>>
 
 /// Loads one or more certs from every given file.
 fn load_certs<'a, I>(files: I) -> openpgp::Result<Vec<Cert>>
-    where I: Iterator<Item=&'a str>
+    where I: Iterator<Item=&'a Path>
 {
     let mut certs = vec![];
     for f in files {
@@ -302,7 +302,7 @@ impl<'store> Config<'store> {
     ///
     /// This is suitable for any kind of OpenPGP data, or decrypted or
     /// authenticated payloads.
-    fn create_or_stdout_safe(&self, f: Option<&str>)
+    fn create_or_stdout_safe(&self, f: Option<&Path>)
                              -> Result<Box<dyn io::Write + Sync + Send>> {
         Config::create_or_stdout(f, self.force)
     }
@@ -312,7 +312,7 @@ impl<'store> Config<'store> {
     ///
     /// If our heuristic detects non-interactive use, we will emit a
     /// warning.
-    fn create_or_stdout_unsafe(&mut self, f: Option<&str>)
+    fn create_or_stdout_unsafe(&mut self, f: Option<&Path>)
                                -> Result<Box<dyn io::Write + Sync + Send>> {
         if ! self.unstable_cli_warning_emitted {
             emit_unstable_cli_warning();
@@ -323,7 +323,7 @@ impl<'store> Config<'store> {
 
     /// Opens the file (or stdout) for writing data that is safe for
     /// non-interactive use because it is an OpenPGP data stream.
-    fn create_or_stdout_pgp<'a>(&self, f: Option<&str>,
+    fn create_or_stdout_pgp<'a>(&self, f: Option<&Path>,
                                 binary: bool, kind: armor::Kind)
                                 -> Result<Message<'a>> {
         let sink = self.create_or_stdout_safe(f)?;
@@ -337,15 +337,14 @@ impl<'store> Config<'store> {
     /// Helper function, do not use directly. Instead, use create_or_stdout_safe
     /// or create_or_stdout_unsafe.
     fn create_or_stdout(
-        f: Option<&str>,
+        f: Option<&Path>,
         force: bool,
     ) -> Result<Box<dyn io::Write + Sync + Send>> {
         match f {
             None => Ok(Box::new(io::stdout())),
-            Some(p) if p == "-" => Ok(Box::new(io::stdout())),
+            Some(p) if p == Path::new("-") => Ok(Box::new(io::stdout())),
             Some(f) => {
-                let p = Path::new(f);
+                if !f.exists() || force {
-                if !p.exists() || force {
                     Ok(Box::new(
                         OpenOptions::new()
                             .write(true)
@@ -358,7 +357,7 @@ impl<'store> Config<'store> {
                     Err(anyhow::anyhow!(format!(
                         "File {:?} exists, use \"sq --force ...\" to \
                                 overwrite",
-                        p
+                        f.display()
                     )))
                 }
             }

src/sq_cli/armor.rs

@@ -3,7 +3,6 @@ use clap::Parser;
 use crate::sq_cli::types::{ArmorKind, IoArgs};
 
 // TODO?: Option<_> conflicts with default value
-// TODO: Use PathBuf as input type for more type safety? Investigate conversion
 // TODO: use indoc to transparently (de-)indent static strings
 #[derive(Parser, Debug)]
 #[clap(

src/sq_cli/certify.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::Parser;
 
 use crate::sq_cli::THIRD_PARTY_CERTIFICATION_VALIDITY_DURATION;
@@ -52,7 +54,7 @@ pub struct Command {
         value_name = "FILE",
         help = "Writes to FILE or stdout if omitted"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
     #[clap(
         short = 'B',
         long,
@@ -184,7 +186,7 @@ pub struct Command {
         index = 1,
         help = "Creates the certification using CERTIFIER-KEY.",
     )]
-    pub certifier: String,
+    pub certifier: PathBuf,
     #[clap(
         value_name = "CERTIFICATE",
         required = true,

src/sq_cli/dane.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::{Args, Parser, Subcommand};
 
 use crate::sq_cli::types::NetworkPolicy;
@@ -66,5 +68,5 @@ pub struct GetCommand {
         value_name = "FILE",
         help = "Writes to FILE instead of importing into the certificate store"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
 }

src/sq_cli/decrypt.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::Parser;
 
 use crate::sq_cli::types::{IoArgs, SessionKey};
@@ -62,13 +64,13 @@ pub struct Command {
         value_name = "CERT_FILE",
         help = "Verifies signatures using the certificates in CERT_FILE",
     )]
-    pub sender_cert_file: Vec<String>,
+    pub sender_cert_file: Vec<PathBuf>,
     #[clap(
         long = "recipient-file",
         value_name = "KEY_FILE",
         help = "Decrypts the message using the key in KEY_FILE",
     )]
-    pub secret_key_file: Vec<String>,
+    pub secret_key_file: Vec<PathBuf>,
     #[clap(
         long = "private-key-store",
         value_name = "KEY_STORE",

src/sq_cli/encrypt.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::ArgAction::Count;
 use clap::{ValueEnum, Parser};
 
@@ -71,14 +73,14 @@ pub struct Command {
         value_name = "CERT_RING_FILE",
         help = "Encrypts to all certificates in CERT_RING_FILE",
     )]
-    pub recipients_file: Vec<String>,
+    pub recipients_file: Vec<PathBuf>,
 
     #[clap(
         long = "signer-file",
         value_name = "KEY_FILE",
         help = "Signs the message using the key in KEY_FILE",
     )]
-    pub signer_key_file: Vec<String>,
+    pub signer_key_file: Vec<PathBuf>,
     #[clap(
         long = "private-key-store",
         value_name = "KEY_STORE",

src/sq_cli/import.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::Parser;
 
 #[derive(Parser, Debug)]
@@ -16,5 +18,5 @@ $ sq import < juliet.pgp
 )]
 pub struct Command {
     #[clap(value_name = "FILE", help = "Reads from FILE or stdin if omitted")]
-    pub input: Vec<String>,
+    pub input: Vec<PathBuf>,
 }

src/sq_cli/inspect.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::Parser;
 
 use sequoia_openpgp as openpgp;
@@ -43,7 +45,7 @@ pub struct Command {
         value_name = "FILE",
         help = "Reads from FILE or stdin if omitted",
     )]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         long = "cert",
         value_name = "FINGERPRINT|KEYID",

src/sq_cli/key.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::{ValueEnum, ArgGroup, Args, Parser, Subcommand};
 
 use sequoia_openpgp::cert::CipherSuite as SqCipherSuite;
@@ -180,8 +182,7 @@ pub struct GenerateCommand {
         value_name = "OUTFILE",
         help = "Writes the key to OUTFILE",
     )]
-    // TODO this represents a filename, so it should be a Path
+    pub export: Option<PathBuf>,
-    pub export: Option<String>,
     #[clap(
         long = "rev-cert",
         value_name = "FILE or -",
@@ -192,8 +193,7 @@ pub struct GenerateCommand {
             mandatory if OUTFILE is \"-\". \
             [default: <OUTFILE>.rev]",
     )]
-    // TODO this represents a filename, so it should be a Path
+    pub rev_cert: Option<PathBuf>
-    pub rev_cert: Option<String>
 }
 
 #[derive(ValueEnum, Clone, Debug)]
@@ -472,14 +472,14 @@ pub struct AdoptCommand {
         value_name = "TARGET-KEY",
         help = "Adds keys to TARGET-KEY",
     )]
-    pub certificate: Option<String>,
+    pub certificate: Option<PathBuf>,
     #[clap(
         short,
         long,
         value_name = "FILE",
         help = "Writes to FILE or stdout if omitted"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
     #[clap(
         short = 'B',
         long,
@@ -532,14 +532,14 @@ pub struct AttestCertificationsCommand {
         value_name = "KEY",
         help = "Changes attestations on KEY",
     )]
-    pub key: Option<String>,
+    pub key: Option<PathBuf>,
     #[clap(
         short,
         long,
         value_name = "FILE",
         help = "Writes to FILE or stdout if omitted"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
     #[clap(
         short = 'B',
         long,

src/sq_cli/keyring.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::{Args, Parser, Subcommand};
 
 #[derive(Parser, Debug)]
@@ -75,14 +77,14 @@ $ sq keyring filter --domain example.org --prune-certs certs.pgp
 )]
 pub struct FilterCommand {
     #[clap(value_name = "FILE", help = "Reads from FILE or stdin if omitted")]
-    pub input: Vec<String>,
+    pub input: Vec<PathBuf>,
     #[clap(
         short,
         long,
         value_name = "FILE",
         help = "Writes to FILE or stdout if omitted"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
     #[clap(
         long = "userid",
         value_name = "USERID",
@@ -173,14 +175,14 @@ $ sq keyring join juliet.pgp romeo.pgp alice.pgp
 )]
 pub struct JoinCommand {
     #[clap(value_name = "FILE", help = "Sets the input files to use")]
-    pub input: Vec<String>,
+    pub input: Vec<PathBuf>,
     #[clap(
         short,
         long,
         value_name = "FILE",
         help = "Sets the output file to use"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
     #[clap(
         short = 'B',
         long = "binary",
@@ -212,14 +214,14 @@ pub struct MergeCommand {
         value_name = "FILE",
         help = "Reads from FILE",
     )]
-    pub input: Vec<String>,
+    pub input: Vec<PathBuf>,
     #[clap(
         short,
         long,
         value_name = "FILE",
         help = "Writes to FILE or stdout if omitted"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
     #[clap(
         short = 'B',
         long = "binary",
@@ -252,7 +254,7 @@ pub struct ListCommand {
         value_name = "FILE",
         help = "Reads from FILE or stdin if omitted",
     )]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         long = "all-userids",
         help = "Lists all user ids",
@@ -289,7 +291,7 @@ pub struct SplitCommand {
         value_name = "FILE",
         help = "Reads from FILE or stdin if omitted",
     )]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         short = 'p',
         long = "prefix",

src/sq_cli/keyserver.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::{Args, Parser, Subcommand};
 
 use crate::sq_cli::types::NetworkPolicy;
@@ -65,7 +67,7 @@ pub struct GetCommand {
         value_name = "FILE",
         help = "Writes to FILE instead of importing into the certificate store"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
     #[clap(
         short = 'B',
         long,
@@ -87,5 +89,5 @@ pub struct GetCommand {
 )]
 pub struct SendCommand {
     #[clap(value_name = "FILE", help = "Reads from FILE or stdin if omitted")]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
 }

src/sq_cli/packet.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::{Args, Parser, Subcommand};
 
 use crate::sq_cli::types::{ArmorKind, IoArgs, SessionKey};
@@ -113,7 +115,7 @@ pub struct DecryptCommand {
         value_name = "KEY_FILE",
         help = "Decrypts the message using the key in KEY_FILE",
     )]
-    pub secret_key_file: Vec<String>,
+    pub secret_key_file: Vec<PathBuf>,
     #[clap(
         long = "private-key-store",
         value_name = "KEY_STORE",
@@ -153,7 +155,7 @@ $ sq packet split juliet.pgp
 )]
 pub struct SplitCommand {
     #[clap(value_name = "FILE", help = "Reads from FILE or stdin if omitted")]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         short = 'p',
         long = "prefix",
@@ -187,14 +189,14 @@ $ sq packet join juliet.pgp-[0-3]*
 )]
 pub struct JoinCommand {
     #[clap(value_name = "FILE", help = "Reads from FILE or stdin if omitted")]
-    pub input: Vec<String>,
+    pub input: Vec<PathBuf>,
     #[clap(
         short,
         long,
         value_name = "FILE",
         help = "Writes to FILE or stdout if omitted"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
     #[clap(
         long = "label",
         value_name = "LABEL",

src/sq_cli/revoke.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::Parser;
 use clap::{ValueEnum, Args, Subcommand};
 
@@ -89,7 +91,7 @@ pub struct CertificateCommand {
 "Reads the certificate to revoke from FILE or stdin, if omitted.  It is \
 an error for the file to contain more than one certificate.",
     )]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         long = "revocation-file",
         value_name = "KEY_FILE",
@@ -100,7 +102,7 @@ different from the certificate, this creates a third-party revocation.  If \
 this option is not provided, and the certificate includes secret key material, \
 then that key is used to sign the revocation certificate.",
     )]
-    pub secret_key_file: Option<String>,
+    pub secret_key_file: Option<PathBuf>,
     #[clap(
         long = "private-key-store",
         value_name = "KEY_STORE",
@@ -234,7 +236,7 @@ pub struct SubkeyCommand {
 if omitted.  It is an error for the file to contain more than one \
 certificate."
     )]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         long = "revocation-file",
         value_name = "KEY_FILE",
@@ -246,7 +248,7 @@ is different from the certificate, this creates a third-party revocation.  \
 If this option is not provided, and the certificate includes secret key \
 material, then that key is used to sign the revocation certificate.",
     )]
-    pub secret_key_file: Option<String>,
+    pub secret_key_file: Option<PathBuf>,
     #[clap(
         long = "private-key-store",
         value_name = "KEY_STORE",
@@ -365,7 +367,7 @@ pub struct UseridCommand {
 if omitted.  It is an error for the file to contain more than one \
 certificate."
     )]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         long = "revocation-file",
         value_name = "KEY_FILE",
@@ -376,7 +378,7 @@ different from the certificate, this creates a third-party revocation.  If \
 this option is not provided, and the certificate includes secret key material, \
 then that key is used to sign the revocation certificate.",
     )]
-    pub secret_key_file: Option<String>,
+    pub secret_key_file: Option<PathBuf>,
     #[clap(
         long = "private-key-store",
         value_name = "KEY_STORE",

src/sq_cli/sign.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::Parser;
 
 use crate::sq_cli::types::IoArgs;
@@ -91,13 +93,13 @@ pub struct Command {
         ],
         help = "Merges signatures from the input and SIGNED-MESSAGE",
     )]
-    pub merge: Option<String>,
+    pub merge: Option<PathBuf>,
     #[clap(
         long = "signer-file",
         value_name = "KEY_FILE",
         help = "Signs the message using the key in KEY_FILE",
     )]
-    pub secret_key_file: Vec<String>,
+    pub secret_key_file: Vec<PathBuf>,
     #[clap(
         long,
         value_names = &["NAME", "VALUE"],

src/sq_cli/types.rs

@@ -1,5 +1,6 @@
 use std::fmt::Display;
 use std::fmt::Formatter;
+use std::path::PathBuf;
 use std::str::FromStr;
 use std::time::Duration;
 use std::time::SystemTime;
@@ -22,14 +23,14 @@ use crate::sq_cli::SECONDS_IN_YEAR;
 #[derive(Debug, Args)]
 pub struct IoArgs {
     #[clap(value_name = "FILE", help = "Reads from FILE or stdin if omitted")]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         short,
         long,
         value_name = "FILE",
         help = "Writes to FILE or stdout if omitted"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
 }
 
 #[derive(ValueEnum, Debug, Clone)]

src/sq_cli/verify.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::Parser;
 
 use sequoia_openpgp as openpgp;
@@ -83,10 +85,7 @@ pub struct Command {
     )]
     // TODO: Should at least one sender_file be required? Verification does not make sense
     // without one, does it?
-    // TODO Use PathBuf instead of String. Path representation is platform dependent, so Rust's
+    pub sender_file: Vec<PathBuf>,
-    // utf-8 Strings are not quite appropriate.
-    // TODO: And adapt load_certs in sq.rs
-    pub sender_file: Vec<String>,
     #[clap(
         long = "signer-cert",
         value_name = "FINGERPRINT|KEYID",

src/sq_cli/wkd.rs

@@ -1,3 +1,5 @@
+use std::path::PathBuf;
+
 use clap::{Args, Parser, Subcommand};
 
 use crate::sq_cli::types::NetworkPolicy;
@@ -92,7 +94,7 @@ pub struct GetCommand {
         value_name = "FILE",
         help = "Writes to FILE instead of importing into the certificate store"
     )]
-    pub output: Option<String>,
+    pub output: Option<PathBuf>,
 }
 
 #[derive(Debug, Args)]
@@ -139,7 +141,7 @@ pub struct GenerateCommand {
         value_name = "CERT-RING",
         help = "Adds certificates from CERT-RING to the WKD",
     )]
-    pub input: Option<String>,
+    pub input: Option<PathBuf>,
     #[clap(
         short = 'd',
         long = "direct-method",