Improve error handling

7 files changed, 83 insertions, 75 deletions

diff --git a/src/backends/clang.rs b/src/backends/clang.rs
index 0947b49..11c316a 100644
--- a/src/backends/clang.rs
+++ b/src/backends/clang.rs
@@ -5,7 +5,7 @@ use std::io::{ Result as IoResult, Error, ErrorKind };
 use std::process::{ Command };
 use std::collections::hash_map::DefaultHasher;
 use std::hash::{ Hash, Hasher };
-use crate::wait::{ WaitInfo, wait_child };
+use crate::wait::{ ChildExitStatus, wait_child };
 use std::time::Duration;
 
 
@@ -81,7 +81,7 @@ impl Backend for ClangBackend {
         }
     }
 
-    fn run(&self, fname: &Path) -> Result<WaitInfo, RunError> {
+    fn run(&self, fname: &Path) -> Result<ChildExitStatus, RunError> {
         let binary_fname = self.build(fname)?;
 
         let proc = Command::new(&binary_fname)
diff --git a/src/backends/mod.rs b/src/backends/mod.rs
index 3bf9fc7..a5d2d28 100644
--- a/src/backends/mod.rs
+++ b/src/backends/mod.rs
@@ -2,7 +2,7 @@ use std::path::{ Path, PathBuf };
 use std::env::temp_dir;
 use lazy_static::lazy_static;
 use std::io::{ Error, ErrorKind };
-use crate::wait::{ WaitInfo };
+use crate::wait::ChildExitStatus;
 
 pub mod python;
 pub mod clang;
@@ -21,7 +21,7 @@ lazy_static! {
 pub trait Backend {
     fn get_template(&self) -> Option<&str>;
 
-    fn run(&self, fname: &Path) -> Result<WaitInfo, RunError>;
+    fn run(&self, fname: &Path) -> Result<ChildExitStatus, RunError>;
 }
 
 fn mk_tmp_dir() -> std::io::Result<&'static std::path::PathBuf> {
diff --git a/src/backends/python.rs b/src/backends/python.rs
index e3569b1..3ee7b35 100644
--- a/src/backends/python.rs
+++ b/src/backends/python.rs
@@ -2,7 +2,7 @@ use serde_derive::{ Serialize, Deserialize };
 use crate::backends::{ Backend, RunError };
 use std::process::{ Command };
 use std::path::Path;
-use crate::wait::{ wait_child, WaitInfo };
+use crate::wait::{ wait_child, ChildExitStatus };
 
 #[derive(Debug, Serialize, Deserialize, Default)]
 pub struct PythonBackend {
@@ -32,7 +32,7 @@ impl Backend for PythonBackend {
         }
     }
 
-    fn run(&self, fname: &Path) -> Result<WaitInfo, RunError> {
+    fn run(&self, fname: &Path) -> Result<ChildExitStatus, RunError> {
         let timer = std::time::Instant::now();
 
         let child = Command::new(self.get_interpreter())
diff --git a/src/conf.rs b/src/conf.rs
index febfef5..cc281f0 100644
--- a/src/conf.rs
+++ b/src/conf.rs
@@ -1,14 +1,12 @@
 use serde_derive::{ Serialize, Deserialize };
 use std::path::{ PathBuf, Path };
 use toml::de;
-use log::{ error, trace };
-use std::io::prelude::*;
-use nix::sys::wait::WaitStatus;
+use log::{ error };
 
 type Error = std::io::Error;
 use std::io::ErrorKind;
 
-use crate::backends::{ Backend, PythonBackend, ClangBackend, RunError };
+use crate::backends::{ Backend, PythonBackend, ClangBackend };
 
 
 #[derive(Debug, Serialize, Deserialize, Default)]
@@ -42,51 +40,6 @@ impl Conf {
             _ => None
         }
     }
-
-    pub fn run(
-        &self,
-        fname: &Path,
-        show_time: bool,
-        show_mem: bool
-    ) -> Result<(), RunError> {
-        match self.get_backend(fname) {
-            Some(backend) => backend.run(fname).map(|info| {
-                match info.status {
-                    WaitStatus::Exited(_pid, ret) => match ret {
-                        0 => {
-                            if show_time {
-                                println!("wall time: {:?}", info.wall_time);
-                            }
-                            if show_mem {
-                                println!("rss: {}K", info.usage.ru_maxrss);
-                            }
-                        },
-                        _ => error!("process exited with {}", ret)
-                    },
-                    WaitStatus::Signaled(pid, sig, coredump) => {
-                        error!(
-                            "process killed by {} {}. was {}",
-                            sig,
-                            if coredump {"(core dumped)"} else {""},
-                            pid
-                        );
-                    },
-                    _ => error!("process signaled, but not exited")
-                }
-            }),
-            None => Err(Error::new(ErrorKind::InvalidData, "Backend not found").into())
-        }
-    }
-
-    pub fn make(&self, fname: &Path) -> Result<(), RunError> {
-        trace!("Template: {:?}", self.get_template(&fname));
-
-        std::fs::File::create(fname)?
-            .write_all(self.get_template(fname).as_bytes())?;
-
-        trace!("Written some bytes to {}", fname.to_string_lossy());
-        Ok(())
-    }
 }
 
 
diff --git a/src/main.rs b/src/main.rs
index 1621e1b..4eeb298 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ extern crate lazy_static;
 use clap::{ AppSettings, App, Arg };
 use env_logger;
 use log::{ error };
+use std::io::prelude::*;
 
 mod conf;
 mod backends;
@@ -41,19 +42,28 @@ fn main() {
                                               .into();
     let config = conf::get_conf();
 
-    let result =
-        if src_path.exists() {
-            config.run(
-                &src_path,
-                matches.is_present("time"),
-                matches.is_present("mem")
-            )
+    if src_path.exists() {
+        if let Some(backend) = config.get_backend(&src_path) {
+            match backend.run(&src_path) {
+                Ok(status) => {
+                    if matches.is_present("time") {
+                        println!("wall time: {:?}", status.wall_time);
+                    }
+                    if matches.is_present("mem") {
+                        println!("rss: {}K", status.usage.ru_maxrss);
+                    }
+                },
+                Err(err) => error!("{}", err)
+            };
         } else {
-            config.make(&src_path)
-        };
-
-    match result {
-        Ok(_) => {},
-        Err(err) => error!("{}", err)
-    }
+            error!("could not match backend");
+        }
+    } else {
+        let template = config.get_template(&src_path).as_bytes();
+        if let Err(err) =
+            std::fs::File::create(&src_path)
+                .and_then(|mut file| file.write_all(template)) {
+            error!("{}", err);
+        }
+    };
 }
diff --git a/src/wait/error.rs b/src/wait/error.rs
index bb95e81..169097d 100644
--- a/src/wait/error.rs
+++ b/src/wait/error.rs
@@ -2,11 +2,22 @@ use nix;
 use std::time::Duration;
 
 #[derive(Debug)]
+pub struct ProcessSignalInfo {
+    pub pid: nix::unistd::Pid,
+    pub signal: nix::sys::signal::Signal,
+    pub coredump: bool
+}
+
+#[derive(Debug)]
 pub enum WaitError {
     TimedOut(Duration),
-    OsError(nix::Error)
+    ReturnNonZero(i32, nix::unistd::Pid),
+    Signaled(ProcessSignalInfo),
+    OsError(nix::Error),
+    NotExited
 }
 
+
 impl From<nix::Error> for WaitError {
     fn from(err: nix::Error) -> Self {
         WaitError::OsError(err)
@@ -17,7 +28,13 @@ impl std::fmt::Display for WaitError {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match *self {
             WaitError::TimedOut(dur) => write!(f, "process timed out in {:?}", dur),
-            WaitError::OsError(err) => err.fmt(f)
+            WaitError::ReturnNonZero(ret, pid) =>
+                write!(f, "process exited with non-zero exit code ({}). was {}", ret, pid),
+            WaitError::Signaled(ref info) =>
+                write!(f, "process killed by {} {}. was {}",
+                       info.signal, if info.coredump {"(core dumped)"} else {""}, info.pid),
+            WaitError::OsError(err) => err.fmt(f),
+            WaitError::NotExited => write!(f, "process signaled, but not exited")
         }
     }
 }
@@ -25,7 +42,10 @@ impl std::fmt::Display for WaitError {
 impl std::error::Error for WaitError {
     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
         match *self {
-            WaitError::TimedOut(_) => None,
+            WaitError::TimedOut(_) |
+            WaitError::ReturnNonZero(_, _) |
+            WaitError::Signaled(_) |
+            WaitError::NotExited => None,
             WaitError::OsError(ref e) => Some(e)
         }
     }
diff --git a/src/wait/mod.rs b/src/wait/mod.rs
index 9761f08..c591bb1 100644
--- a/src/wait/mod.rs
+++ b/src/wait/mod.rs
@@ -8,20 +8,45 @@ use std::time::{ Instant, Duration };
 use std::process::Child;
 use std::thread;
 use std::sync::mpsc;
+use std::convert::{ TryFrom, TryInto };
 
 mod error;
 mod rusage_ffi;
 pub use rusage_ffi::Rusage;
 
 pub use error::WaitError;
+use error::ProcessSignalInfo;
 
 #[derive(Debug)]
-pub struct WaitInfo {
+struct WaitInfo {
     pub status: WaitStatus,
     pub usage: Rusage,
     pub wall_time: Duration
 }
 
+#[derive(Debug)]
+pub struct ChildExitStatus {
+    pub usage: Rusage,
+    pub wall_time: Duration
+}
+
+impl TryFrom<WaitInfo> for ChildExitStatus {
+    type Error = WaitError;
+
+    fn try_from(info: WaitInfo) -> Result<Self, Self::Error> {
+        match info.status {
+            WaitStatus::Exited(pid, ret) =>
+                match ret {
+                    0 => Ok(ChildExitStatus { usage: info.usage, wall_time: info.wall_time }),
+                    _ => Err(WaitError::ReturnNonZero(ret, pid))
+                },
+            WaitStatus::Signaled(pid, signal, coredump) =>
+                Err(WaitError::Signaled(ProcessSignalInfo { pid, signal, coredump })),
+            _ => Err(WaitError::NotExited)
+        }
+    }
+}
+
 
 fn wait4_pid(
     pid: Pid,
@@ -57,14 +82,14 @@ pub fn wait_child(
     mut child: Child,
     timeout: Duration,
     timer: Instant
-) -> Result<WaitInfo, WaitError> {
+) -> Result<ChildExitStatus, WaitError> {
     let pid = Pid::from_raw(child.id() as i32);
     let (send, recv) = mpsc::channel();
 
     let thr = thread::spawn(move || wait4_pid(pid, send, timer));
 
     match recv.recv_timeout(timeout) {
-        Ok(Ok(usg)) => Ok(usg),
+        Ok(Ok(wait_info)) => wait_info.try_into(),
         Ok(Err(err)) => Err(err.into()),
         Err(mpsc::RecvTimeoutError::Timeout) => {
             drop(recv);