From 8110b4ebb29174ecd4b22510da0285abf604b8a7 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Tue, 10 Sep 2019 21:55:32 +0200
Subject: [PATCH] Rust cleanup

---
 nix-rust/Cargo.toml     |  1 +
 nix-rust/src/error.rs   |  5 +++
 nix-rust/src/foreign.rs | 14 +++++++++
 nix-rust/src/lib.rs     | 68 ++++-------------------------------------
 nix-rust/src/tarfile.rs | 47 ++++++++++++++++++++++++++++
 src/libstore/rust.hh    |  2 +-
 6 files changed, 74 insertions(+), 63 deletions(-)
 create mode 100644 nix-rust/src/error.rs
 create mode 100644 nix-rust/src/foreign.rs
 create mode 100644 nix-rust/src/tarfile.rs

diff --git a/nix-rust/Cargo.toml b/nix-rust/Cargo.toml
index 2d2bf6752..8b56dc89c 100644
--- a/nix-rust/Cargo.toml
+++ b/nix-rust/Cargo.toml
@@ -2,6 +2,7 @@
 name = "nix-rust"
 version = "0.1.0"
 authors = ["Eelco Dolstra <edolstra@gmail.com>"]
+edition = "2018"
 
 [lib]
 name = "nixrust"
diff --git a/nix-rust/src/error.rs b/nix-rust/src/error.rs
new file mode 100644
index 000000000..28d0abdef
--- /dev/null
+++ b/nix-rust/src/error.rs
@@ -0,0 +1,5 @@
+#[derive(Debug)]
+pub enum Error {
+    Misc(String),
+    Foreign(libc::c_void), // == std::exception_ptr
+}
diff --git a/nix-rust/src/foreign.rs b/nix-rust/src/foreign.rs
new file mode 100644
index 000000000..7bce7753c
--- /dev/null
+++ b/nix-rust/src/foreign.rs
@@ -0,0 +1,14 @@
+/// A wrapper around Nix's Source class that provides the Read trait.
+#[repr(C)]
+pub struct Source {
+    fun: extern "C" fn(this: *mut libc::c_void, data: &mut [u8]) -> usize,
+    this: *mut libc::c_void,
+}
+
+impl std::io::Read for Source {
+    fn read(&mut self, buf: &mut [u8]) -> std::result::Result<usize, std::io::Error> {
+        let n = (self.fun)(self.this, buf);
+        assert!(n <= buf.len());
+        Ok(n)
+    }
+}
diff --git a/nix-rust/src/lib.rs b/nix-rust/src/lib.rs
index ac6dee543..192ca29e4 100644
--- a/nix-rust/src/lib.rs
+++ b/nix-rust/src/lib.rs
@@ -1,66 +1,10 @@
-extern crate libc;
-extern crate tar;
+mod error;
+mod foreign;
+mod tarfile;
 
-use std::fs;
-use std::io;
-use std::os::unix::fs::OpenOptionsExt;
-use std::path::Path;
-use tar::Archive;
-
-/// A wrapper around Nix's Source class that provides the Read trait.
-#[repr(C)]
-pub struct Source {
-    fun: extern "C" fn(this: *mut libc::c_void, data: &mut [u8]) -> usize,
-    this: *mut libc::c_void,
-}
-
-impl std::io::Read for Source {
-    fn read(&mut self, buf: &mut [u8]) -> std::result::Result<usize, std::io::Error> {
-        let n = (self.fun)(self.this, buf);
-        assert!(n <= buf.len());
-        Ok(n)
-    }
-}
+pub use error::Error;
 
 #[no_mangle]
-pub extern "C" fn unpack_tarfile(source: Source, dest_dir: &str) -> bool {
-    // FIXME: handle errors.
-
-    let dest_dir = Path::new(dest_dir);
-
-    let mut tar = Archive::new(source);
-
-    for file in tar.entries().unwrap() {
-        let mut file = file.unwrap();
-
-        let dest_file = dest_dir.join(file.path().unwrap());
-
-        fs::create_dir_all(dest_file.parent().unwrap()).unwrap();
-
-        match file.header().entry_type() {
-            tar::EntryType::Directory => {
-                fs::create_dir(dest_file).unwrap();
-            }
-            tar::EntryType::Regular => {
-                let mode = if file.header().mode().unwrap() & libc::S_IXUSR == 0 {
-                    0o666
-                } else {
-                    0o777
-                };
-                let mut f = fs::OpenOptions::new()
-                    .create(true)
-                    .write(true)
-                    .mode(mode)
-                    .open(dest_file)
-                    .unwrap();
-                io::copy(&mut file, &mut f).unwrap();
-            }
-            tar::EntryType::Symlink => {
-                std::os::unix::fs::symlink(file.header().link_name().unwrap().unwrap(), dest_file).unwrap();
-            }
-            t => panic!("Unsupported tar entry type '{:?}'.", t),
-        }
-    }
-
-    true
+pub extern "C" fn unpack_tarfile(source: foreign::Source, dest_dir: &str) {
+    tarfile::unpack_tarfile(source, dest_dir).unwrap();
 }
diff --git a/nix-rust/src/tarfile.rs b/nix-rust/src/tarfile.rs
new file mode 100644
index 000000000..696118e4d
--- /dev/null
+++ b/nix-rust/src/tarfile.rs
@@ -0,0 +1,47 @@
+use crate::{foreign::Source, Error};
+use std::fs;
+use std::io;
+use std::os::unix::fs::OpenOptionsExt;
+use std::path::Path;
+use tar::Archive;
+
+pub fn unpack_tarfile(source: Source, dest_dir: &str) -> Result<(), Error> {
+    let dest_dir = Path::new(dest_dir);
+
+    let mut tar = Archive::new(source);
+
+    for file in tar.entries().unwrap() {
+        let mut file = file.unwrap();
+
+        let dest_file = dest_dir.join(file.path().unwrap());
+
+        fs::create_dir_all(dest_file.parent().unwrap()).unwrap();
+
+        match file.header().entry_type() {
+            tar::EntryType::Directory => {
+                fs::create_dir(dest_file).unwrap();
+            }
+            tar::EntryType::Regular => {
+                let mode = if file.header().mode().unwrap() & libc::S_IXUSR == 0 {
+                    0o666
+                } else {
+                    0o777
+                };
+                let mut f = fs::OpenOptions::new()
+                    .create(true)
+                    .write(true)
+                    .mode(mode)
+                    .open(dest_file)
+                    .unwrap();
+                io::copy(&mut file, &mut f).unwrap();
+            }
+            tar::EntryType::Symlink => {
+                std::os::unix::fs::symlink(file.header().link_name().unwrap().unwrap(), dest_file)
+                    .unwrap();
+            }
+            t => return Err(Error::Misc(format!("unsupported tar entry type '{:?}'", t))),
+        }
+    }
+
+    Ok(())
+}
diff --git a/src/libstore/rust.hh b/src/libstore/rust.hh
index 7e6c2f54d..4366e4723 100644
--- a/src/libstore/rust.hh
+++ b/src/libstore/rust.hh
@@ -40,5 +40,5 @@ struct Source
 }
 
 extern "C" {
-    bool unpack_tarfile(rust::Source source, rust::StringSlice dest_dir);
+    void unpack_tarfile(rust::Source source, rust::StringSlice dest_dir);
 }