refactor(users/Profpatsch): move arglib_netencode into its own lib r/2167

arglib is the simple idea of passing structured data via a
conventional environment variable instead of implementing an optparser
for every little tool.

Pop the envvar, decode the contents, return the contents.

Change-Id: Ie44148293a58aae9a0a613895176227d43b491bb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2449
Tested-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

2 files changed, 43 insertions, 21 deletions

diff --git a/users/Profpatsch/arglib/default.nix b/users/Profpatsch/arglib/default.nix
new file mode 100644
index 000000000000..4f9f8e4cae79
--- /dev/null
+++ b/users/Profpatsch/arglib/default.nix
@@ -0,0 +1,40 @@
+{ depot, pkgs, lib, ... }:
+
+let
+  netencode = {
+    rust = depot.users.Profpatsch.writers.rustSimpleLib {
+      name = "arglib-netencode";
+      dependencies = [
+        depot.users.Profpatsch.netencode.netencode-rs
+      ];
+    } ''
+      extern crate netencode;
+
+      use netencode::{T};
+      use std::os::unix::ffi::OsStrExt;
+
+      pub fn arglib_netencode(env: Option<&std::ffi::OsStr>) -> Result<T, String> {
+          let env = match env {
+              None => std::ffi::OsStr::from_bytes("ARGLIB_NETENCODE".as_bytes()),
+              Some(a) => a
+          };
+          match std::env::var_os(env) {
+              None => Err(format!("could not read args, envvar {} not set", env.to_string_lossy())),
+              // TODO: good error handling for the different parser errors
+              Some(soup) => match netencode::parse::t_t(soup.as_bytes()) {
+                  Ok((remainder, t)) => match remainder.is_empty() {
+                      true => Ok(t),
+                      false => Err(format!("there was some unparsed bytes remaining: {:?}", remainder))
+                  },
+                  Err(err) => Err(format!("parsing error: {:?}", err))
+              }
+          }
+      }
+    '';
+  };
+
+in {
+   inherit
+    netencode
+    ;
+}
diff --git a/users/Profpatsch/netencode/netencode-mustache.rs b/users/Profpatsch/netencode/netencode-mustache.rs
index 796c7a68d4bb..5c7242ed0869 100644
--- a/users/Profpatsch/netencode/netencode-mustache.rs
+++ b/users/Profpatsch/netencode/netencode-mustache.rs
@@ -1,5 +1,6 @@
 extern crate netencode;
 extern crate mustache;
+extern crate arglib_netencode;
 
 use mustache::{Data};
 use netencode::{T};
@@ -7,25 +8,6 @@ use std::collections::HashMap;
 use std::os::unix::ffi::{OsStrExt};
 use std::io::{Read};
 
-fn arglib_netencode(env: Option<&std::ffi::OsStr>) -> Result<T, String> {
-    let env = match env {
-        None => std::ffi::OsStr::from_bytes("ARGLIB_NETENCODE".as_bytes()),
-        Some(a) => a
-    };
-    match std::env::var_os(env) {
-        None => Err(format!("could not read args, envvar {} not set", env.to_string_lossy())),
-        // TODO: good error handling for the different parser errors
-        Some(soup) => match netencode::parse::t_t(soup.as_bytes()) {
-            Ok((remainder, t)) => match remainder.is_empty() {
-                true => Ok(t),
-                false => Err(format!("there was some unparsed bytes remaining: {:?}", remainder))
-            },
-            Err(err) => Err(format!("parsing error: {:?}", err))
-        }
-    }
-}
-
-
 fn netencode_to_mustache_data_dwim(t: T) -> Data {
     match t {
         // TODO: good idea?
@@ -42,7 +24,7 @@ fn netencode_to_mustache_data_dwim(t: T) -> Data {
         T::Sum(tag) => unimplemented!(),
         T::Record(xs) => Data::Map(
             xs.into_iter()
-                .map(|(key, val)| (key, netencode_to_mustache_data_dwim(*val)))
+                .map(|(key, val)| (key, netencode_to_mustache_data_dwim(val)))
                 .collect::<HashMap<_,_>>()
         ),
         T::List(xs) => Data::Vec(
@@ -55,7 +37,7 @@ fn netencode_to_mustache_data_dwim(t: T) -> Data {
 
 pub fn from_stdin() -> () {
     let data = netencode_to_mustache_data_dwim(
-        arglib_netencode(None).unwrap()
+        arglib_netencode::arglib_netencode(Some(std::ffi::OsStr::new("TEMPLATE_DATA"))).unwrap()
     );
     let mut stdin = String::new();
     std::io::stdin().read_to_string(&mut stdin).unwrap();