From fa477593fa0055a6dc8cff35970135fe4d7fd0dd Mon Sep 17 00:00:00 2001
From: Milo Turner <iitalics@gmail.com>
Date: Sat, 7 Mar 2020 20:43:53 -0500
Subject: [PATCH] goodbye failure crate!!

---
 Cargo.lock            | 74 ++++++++-----------------------------------
 hptp-recv/Cargo.toml  |  4 +--
 hptp-recv/src/main.rs | 37 +++++++++++++++++-----
 3 files changed, 44 insertions(+), 71 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 1a67913..c1397e3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,27 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "backtrace"
-version = "0.3.45"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ad235dabf00f36301792cfe82499880ba54c6486be094d1047b02bacb67c14e8"
-dependencies = [
- "backtrace-sys",
- "cfg-if",
- "libc",
- "rustc-demangle",
-]
-
-[[package]]
-name = "backtrace-sys"
-version = "0.1.33"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e17b52e737c40a7d75abca20b29a19a0eb7ba9fc72c5a72dd282a0a3c2c0dc35"
-dependencies = [
- "cc",
- "libc",
-]
-
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -34,40 +12,12 @@ version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "130aac562c0dd69c56b3b1cc8ffd2e17be31d0b6c25b61c96b76231aa23e39e1"
 
-[[package]]
-name = "cc"
-version = "1.0.50"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "95e28fa049fda1c330bcf9d723be7663a899c4679724b34c81e9f5a326aab8cd"
-
 [[package]]
 name = "cfg-if"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
-[[package]]
-name = "failure"
-version = "0.1.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8529c2421efa3066a5cbd8063d2244603824daccb6936b079010bb2aa89464b"
-dependencies = [
- "backtrace",
- "failure_derive",
-]
-
-[[package]]
-name = "failure_derive"
-version = "0.1.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "030a733c8287d6213886dd487564ff5c8f6aae10278b3588ed177f9d18f8d231"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
- "synstructure",
-]
-
 [[package]]
 name = "fuchsia-zircon"
 version = "0.3.3"
@@ -95,8 +45,8 @@ dependencies = [
 name = "hptp-recv"
 version = "0.1.0"
 dependencies = [
- "failure",
  "hptp",
+ "thiserror",
  "tokio",
 ]
 
@@ -219,12 +169,6 @@ dependencies = [
  "proc-macro2",
 ]
 
-[[package]]
-name = "rustc-demangle"
-version = "0.1.16"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4c691c0e608126e00913e33f0ccf3727d5fc84573623b8d65b2df340b5201783"
-
 [[package]]
 name = "slab"
 version = "0.4.2"
@@ -243,15 +187,23 @@ dependencies = [
 ]
 
 [[package]]
-name = "synstructure"
-version = "0.12.3"
+name = "thiserror"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "67656ea1dc1b41b1451851562ea232ec2e5a80242139f7e679ceccfb5d61f545"
+checksum = "ee14bf8e6767ab4c687c9e8bc003879e042a96fd67a3ba5934eadb6536bef4db"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7b51e1fbc44b5a0840be594fbc0f960be09050f2617e61e6aa43bef97cd3ef4"
 dependencies = [
  "proc-macro2",
  "quote",
  "syn",
- "unicode-xid",
 ]
 
 [[package]]
diff --git a/hptp-recv/Cargo.toml b/hptp-recv/Cargo.toml
index 57b7e1a..5ba6726 100644
--- a/hptp-recv/Cargo.toml
+++ b/hptp-recv/Cargo.toml
@@ -9,5 +9,5 @@ edition = "2018"
 
 [dependencies]
 hptp = { path = "../hptp" }
-tokio = {version = "0.2.*", features = ["rt-core", "io-std", "io-util", "udp"]}
-failure = "0.1.7"
+tokio = { version = "0.2.*", features = ["rt-core", "udp"] }
+thiserror = "*"
diff --git a/hptp-recv/src/main.rs b/hptp-recv/src/main.rs
index d9df368..a0b8feb 100644
--- a/hptp-recv/src/main.rs
+++ b/hptp-recv/src/main.rs
@@ -1,23 +1,34 @@
-extern crate failure;
 extern crate hptp;
 extern crate tokio;
+#[macro_use]
+extern crate thiserror;
 
-use failure::Error;
 use hptp::log::Logger;
 use std::net::Ipv4Addr;
 use tokio::net::UdpSocket;
 
-fn main() -> Result<(), Box<dyn std::error::Error>> {
+#[derive(Error, Debug)]
+enum Error {
+    #[error("io error: {0}")]
+    Io(#[from] tokio::io::Error),
+    #[error("no UDP port available for listening")]
+    NoPortAvail,
+}
+
+fn entry() -> Result<(), Error> {
     let mut rt = tokio::runtime::Runtime::new()?;
     let mut log = Logger::new();
-    let fut = start(&mut log);
-    Ok(rt.block_on(fut)?)
+    rt.block_on(start(&mut log))
+}
+
+fn main() {
+    if let Err(e) = entry() {
+        println!("ERROR: {}", e);
+    }
 }
 
 async fn start(log: &mut Logger) -> Result<(), Error> {
-    let host = (Ipv4Addr::LOCALHOST, 3700);
-    let sock = UdpSocket::bind(host).await?;
-
+    let sock = udp_listen_or_retry(3700, 4).await?;
     log.bound(sock.local_addr()?.port()).await;
 
     let (mut rx, _tx) = sock.split();
@@ -31,3 +42,13 @@ async fn start(log: &mut Logger) -> Result<(), Error> {
         .await;
     }
 }
+
+async fn udp_listen_or_retry(init_port: u16, max_tries: u16) -> Result<UdpSocket, Error> {
+    for tries in 0..max_tries {
+        let port = init_port + tries;
+        if let Ok(sock) = UdpSocket::bind((Ipv4Addr::LOCALHOST, port)).await {
+            return Ok(sock);
+        }
+    }
+    Err(Error::NoPortAvail)
+}