Implement support for conversions of paths (#608)

Author: filmor

rustler/src/types/mod.rs

@@ -3,6 +3,7 @@ use crate::{Env, Error, NifResult, Term};
 #[macro_use]
 pub mod atom;
 pub mod i128;
+pub mod path;
 pub use crate::types::atom::Atom;
 
 pub mod binary;

rustler/src/types/path.rs

@@ -0,0 +1,29 @@
+use crate::{Decoder, Encoder, Env, Error, NifResult, Term};
+use std::path::{Path, PathBuf};
+
+impl Encoder for Path {
+    fn encode<'a>(&self, env: Env<'a>) -> Term<'a> {
+        self.as_os_str().to_str().encode(env)
+    }
+}
+
+impl Encoder for PathBuf {
+    fn encode<'a>(&self, env: Env<'a>) -> Term<'a> {
+        self.as_path().encode(env)
+    }
+}
+
+impl<'a> Decoder<'a> for &'a Path {
+    fn decode(term: Term<'a>) -> NifResult<Self> {
+        let bin = term.decode_as_binary().or(Err(Error::BadArg))?;
+        let s = std::str::from_utf8(bin.as_slice()).or(Err(Error::BadArg))?;
+        Ok(Path::new(s))
+    }
+}
+
+impl<'a> Decoder<'a> for PathBuf {
+    fn decode(term: Term<'a>) -> NifResult<Self> {
+        let s: &str = term.decode()?;
+        Ok(PathBuf::from(s))
+    }
+}

rustler_tests/lib/rustler_test.ex

@@ -133,4 +133,6 @@ defmodule RustlerTest do
   def maybe_add_one_to_tuple(_tuple), do: err()
   def add_i32_from_tuple(_tuple), do: err()
   def greeting_person_from_tuple(_tuple), do: err()
+
+  def append_to_path(_path, _to_append), do: err()
 end

rustler_tests/native/rustler_test/src/lib.rs

@@ -7,6 +7,7 @@ mod test_error;
 mod test_list;
 mod test_map;
 mod test_nif_attrs;
+mod test_path;
 mod test_primitives;
 mod test_range;
 mod test_resource;
@@ -103,6 +104,7 @@ rustler::init!(
         test_codegen::reserved_keywords::reserved_keywords_type_echo,
         test_codegen::generic_types::generic_struct_echo,
         test_codegen::generic_types::mk_generic_map,
+        test_path::append_to_path,
     ],
     load = load
 );

rustler_tests/native/rustler_test/src/test_path.rs

@@ -0,0 +1,8 @@
+use std::path::{Path, PathBuf};
+
+#[rustler::nif]
+pub fn append_to_path(p: &Path, comp: &str) -> PathBuf {
+    let mut p = p.to_path_buf();
+    p.push(comp);
+    p
+}