Switch from failure to anyhow.

  - Use the anyhow crate instead of failure to implement the dynamic
    side of our error handling.  anyhow::Error derefs to dyn
    std::error::Error, allowing better interoperability with other
    stdlib-based error handling libraries.

  - Fixes #444.

5 files changed, 21 insertions, 22 deletions

diff --git a/ipc/Cargo.toml b/ipc/Cargo.toml
index c38aa7bd..745e4d9d 100644
--- a/ipc/Cargo.toml
+++ b/ipc/Cargo.toml
@@ -23,8 +23,8 @@ maintenance = { status = "actively-developed" }
 sequoia-openpgp = { path = "../openpgp", version = "0.15" }
 sequoia-core = { path = "../core", version = "0.15" }
 
+anyhow = "1"
 capnp-rpc = "0.10"
-failure = "0.1.2"
 fs2 = "0.4.2"
 futures = "0.1"
 lalrpop-util = "0.17"
diff --git a/ipc/src/assuan/mod.rs b/ipc/src/assuan/mod.rs
index 75e05f6e..4234b00e 100644
--- a/ipc/src/assuan/mod.rs
+++ b/ipc/src/assuan/mod.rs
@@ -62,7 +62,7 @@ pub struct Client {
 
 enum WriteState {
     Ready(io::WriteHalf<UnixStream>),
-    Sending(future::FromErr<io::WriteAll<io::WriteHalf<tokio::net::UnixStream>, Vec<u8>>, failure::Error>),
+    Sending(future::FromErr<io::WriteAll<io::WriteHalf<tokio::net::UnixStream>, Vec<u8>>, anyhow::Error>),
     Transitioning,
     Dead,
 }
@@ -70,7 +70,7 @@ enum WriteState {
 impl Client {
     /// Connects to the server.
     pub fn connect<P>(path: P)
-        -> impl Future<Item = Client, Error = failure::Error>
+        -> impl Future<Item = Client, Error = anyhow::Error>
         where P: AsRef<Path>
     {
         UnixStream::connect(path).from_err()
@@ -197,7 +197,7 @@ impl ConnectionFuture {
 
 impl Future for ConnectionFuture {
     type Item = Client;
-    type Error = failure::Error;
+    type Error = anyhow::Error;
 
     fn poll(&mut self) -> std::result::Result<Async<Self::Item>, Self::Error> {
         // Consume the initial message from the server.
@@ -227,7 +227,7 @@ impl Future for ConnectionFuture {
 
 impl Stream for Client {
     type Item = Response;
-    type Error = failure::Error;
+    type Error = anyhow::Error;
 
     /// Attempt to pull out the next value of this stream, returning
     /// None if the stream is finished.
@@ -400,7 +400,7 @@ impl Response {
                                  c)?;
                     }
                 }
-                Err(failure::err_msg(
+                Err(anyhow::anyhow!(
                     String::from_utf8_lossy(&msg).to_string()).into())
             },
         }
diff --git a/ipc/src/gnupg.rs b/ipc/src/gnupg.rs
index ec308ca2..5d6f848d 100644
--- a/ipc/src/gnupg.rs
+++ b/ipc/src/gnupg.rs
@@ -111,7 +111,7 @@ impl Context {
         for argument in arguments {
             gpgconf.arg(argument);
         }
-        let output = gpgconf.output().map_err(|e| -> failure::Error {
+        let output = gpgconf.output().map_err(|e| -> anyhow::Error {
             Error::GPGConf(e.to_string()).into()
         })?;
 
@@ -242,7 +242,7 @@ impl DerefMut for Agent {
 
 impl Stream for Agent {
     type Item = assuan::Response;
-    type Error = failure::Error;
+    type Error = anyhow::Error;
 
     /// Attempt to pull out the next value of this stream, returning
     /// None if the stream is finished.
@@ -263,7 +263,7 @@ impl Agent {
     /// server is running for the given context, this operation will
     /// fail.
     pub fn connect<'c>(ctx: &'c Context)
-                   -> impl Future<Item = Self, Error = failure::Error> + 'c
+                   -> impl Future<Item = Self, Error = anyhow::Error> + 'c
     {
         futures::lazy(move || ctx.socket("agent"))
             .and_then(Self::connect_to)
@@ -275,7 +275,7 @@ impl Agent {
     /// server is running for the given context, this operation will
     /// fail.
     pub fn connect_to<P>(path: P)
-                         -> impl Future<Item = Self, Error = failure::Error>
+                         -> impl Future<Item = Self, Error = anyhow::Error>
         where P: AsRef<Path>
     {
         assuan::Client::connect(path)
@@ -288,7 +288,7 @@ impl Agent {
                        key: &'a Key<key::PublicParts, R>,
                        algo: HashAlgorithm, digest: &'a [u8])
         -> impl Future<Item = crypto::mpis::Signature,
-                       Error = failure::Error> + 'a
+                       Error = anyhow::Error> + 'a
         where R: key::KeyRole
     {
         SigningRequest::new(&mut self.c, key, algo, digest)
@@ -300,7 +300,7 @@ impl Agent {
                           key: &'a Key<key::PublicParts, R>,
                           ciphertext: &'a crypto::mpis::Ciphertext)
         -> impl Future<Item = crypto::SessionKey,
-                       Error = failure::Error> + 'a
+                       Error = anyhow::Error> + 'a
         where R: key::KeyRole
     {
         DecryptionRequest::new(&mut self.c, key, ciphertext)
@@ -407,7 +407,7 @@ impl<'a, 'b, 'c, R> Future for SigningRequest<'a, 'b, 'c, R>
     where R: key::KeyRole
 {
     type Item = crypto::mpis::Signature;
-    type Error = failure::Error;
+    type Error = anyhow::Error;
 
     fn poll(&mut self) -> std::result::Result<Async<Self::Item>, Self::Error> {
         use self::SigningRequestState::*;
@@ -555,7 +555,7 @@ impl<'a, 'b, 'c, R> Future for DecryptionRequest<'a, 'b, 'c, R>
     where R: key::KeyRole
 {
     type Item = crypto::SessionKey;
-    type Error = failure::Error;
+    type Error = anyhow::Error;
 
     fn poll(&mut self) -> std::result::Result<Async<Self::Item>, Self::Error> {
         use self::DecryptionRequestState::*;
@@ -713,7 +713,7 @@ impl<'a> crypto::Signer for KeyPair<'a> {
     }
 
     fn sign(&mut self, hash_algo: HashAlgorithm, digest: &[u8])
-            -> Result<openpgp::crypto::mpis::Signature>
+            -> openpgp::Result<openpgp::crypto::mpis::Signature>
     {
         use crate::openpgp::types::PublicKeyAlgorithm::*;
         use crate::openpgp::crypto::mpis::PublicKey;
@@ -745,7 +745,7 @@ impl<'a> crypto::Decryptor for KeyPair<'a> {
 
     fn decrypt(&mut self, ciphertext: &crypto::mpis::Ciphertext,
                _plaintext_len: Option<usize>)
-               -> Result<crypto::SessionKey>
+               -> openpgp::Result<crypto::SessionKey>
     {
         use crate::openpgp::crypto::mpis::{PublicKey, Ciphertext};
 
diff --git a/ipc/src/lib.rs b/ipc/src/lib.rs
index 9526c031..c4946816 100644
--- a/ipc/src/lib.rs
+++ b/ipc/src/lib.rs
@@ -42,7 +42,6 @@ use std::net::{SocketAddr, AddrParseError, TcpStream, TcpListener};
 use std::path::PathBuf;
 
 extern crate capnp_rpc;
-#[macro_use] extern crate failure;
 extern crate fs2;
 extern crate futures;
 extern crate lalrpop_util;
@@ -51,7 +50,7 @@ extern crate tokio;
 extern crate tokio_core;
 extern crate tokio_io;
 
-use failure::Fallible as Result;
+use anyhow::Result;
 use fs2::FileExt;
 use futures::{Future, Stream};
 
@@ -315,7 +314,7 @@ impl Server {
 
         if args.len() != 7 || args[1] != "--home"
             || args[3] != "--lib" || args[5] != "--ephemeral" {
-                return Err(format_err!(
+                return Err(anyhow::anyhow!(
                     "Usage: {} --home <HOMEDIR> --lib <LIBDIR> \
                      --ephemeral true|false", args[0]));
             }
@@ -328,7 +327,7 @@ impl Server {
                 cfg.set_ephemeral();
             }
         } else {
-            return Err(format_err!(
+            return Err(anyhow::anyhow!(
                 "Expected 'true' or 'false' for --ephemeral, got: {}",
                 args[6]));
         }
diff --git a/ipc/tests/gpg-agent.rs b/ipc/tests/gpg-agent.rs
index 25b8a711..45c532e6 100644
--- a/ipc/tests/gpg-agent.rs
+++ b/ipc/tests/gpg-agent.rs
@@ -172,7 +172,7 @@ fn sign() {
                             None => (),
                         }
                     },
-                    _ => return Err(failure::err_msg(
+                    _ => return Err(anyhow::anyhow!(
                         "Unexpected message structure")),
                 }
             }
@@ -180,7 +180,7 @@ fn sign() {
             if good {
                 Ok(()) // Good signature.
             } else {
-                Err(failure::err_msg("Signature verification failed"))
+                Err(anyhow::anyhow!("Signature verification failed"))
             }
         }
     }