add simplified meta syntax, path spec features

2 files changed, 71 insertions, 44 deletions

diff --git a/fondant_derive/Cargo.toml b/fondant_derive/Cargo.toml
index 73a3a19..b93b8a0 100644
--- a/fondant_derive/Cargo.toml
+++ b/fondant_derive/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2018"
 [dependencies]
 proc-macro2 = "1.0.9"
 quote = "1.0"
+directories = "2.0"
 
 [dependencies.syn]
 version = "1.0"
diff --git a/fondant_derive/src/lib.rs b/fondant_derive/src/lib.rs
index 5584d84..946c130 100644
--- a/fondant_derive/src/lib.rs
+++ b/fondant_derive/src/lib.rs
@@ -1,49 +1,63 @@
 extern crate proc_macro;
 
+use ::std::ffi::{OsStr, OsString};
+use ::std::path::{Path, PathBuf};
+use directories::ProjectDirs;
 use proc_macro::TokenStream;
 use proc_macro2::Span;
 use quote::quote;
 use syn::{parse_macro_input, DeriveInput, Error, Ident, Lit, Meta, MetaNameValue, Result};
 
-#[proc_macro_derive(Config, attributes(filename, extension))]
+#[derive(Debug, Default)]
+struct ConfigPath {
+    parent: Option<PathBuf>,
+    filename: Option<OsString>,
+    extension: Option<OsString>,
+}
+
+#[proc_macro_derive(Configure, attributes(config_file))]
 pub fn config_attribute(item: TokenStream) -> TokenStream {
     let ast: DeriveInput = parse_macro_input!(item as DeriveInput);
-    let (filename, filetype) = extract_attributes(&ast);
+    let cfg_path = extract_attributes(&ast);
 
-    gen_impl(
-        &ast,
-        filename.unwrap_or("config".into()),
-        filetype.unwrap_or("toml".into()),
-    )
+    gen_impl(&ast, cfg_path)
 }
 
-fn extract_attributes(ast: &DeriveInput) -> (Option<String>, Option<String>) {
-    let mut filename: Option<String> = None;
-    let mut filetype: Option<String> = None;
+fn extract_attributes(ast: &DeriveInput) -> ConfigPath {
     for option in ast.attrs.iter() {
         let option = option.parse_meta().unwrap();
         match option {
             Meta::NameValue(MetaNameValue {
                 ref path, ref lit, ..
-            }) if path.is_ident("filename") => {
-                if let Lit::Str(f) = lit {
-                    filename = Some(f.value());
-                }
-            }
-            Meta::NameValue(MetaNameValue {
-                ref path, ref lit, ..
-            }) if path.is_ident("extension") => {
+            }) if path.is_ident("config_file") => {
                 if let Lit::Str(f) = lit {
-                    filetype = Some(f.value());
+                    let f = f.value();
+                    let fp = Path::new(&f);
+                    let blank = Path::new("");
+                    let parent = match fp.parent() {
+                        Some(blank) => None,
+                        other => other,
+                    };
+                    return ConfigPath {
+                        parent: parent.map(Path::to_path_buf),
+                        filename: fp.file_stem().map(OsStr::to_os_string),
+                        extension: fp.extension().map(OsStr::to_os_string),
+                    };
                 }
             }
             _ => {}
         }
     }
-    return (filename, filetype);
+    return Default::default();
 }
 
-fn map_ser(ext: &str) -> (Ident, Ident) {
+fn pick_serializer(ext: &str) -> (Ident, Ident) {
+    /* returns serializer and a corresponding function to
+     * stringify with based on file extension
+     * toml::to_string_pretty
+     * serde_yaml::to_string
+     * serde_json::to_string_pretty
+     */
     match ext.as_ref() {
         "toml" => (
             Ident::new("toml", Span::call_site()),
@@ -61,30 +75,48 @@ fn map_ser(ext: &str) -> (Ident, Ident) {
     }
 }
 
-fn gen_impl(ast: &DeriveInput, filename: String, filetype: String) -> TokenStream {
-    let struct_name = &ast.ident.to_string();
+fn gen_impl(ast: &DeriveInput, cfg_path: ConfigPath) -> TokenStream {
     let struct_ident = &ast.ident;
-    let (ser, ser_fn) = map_ser(&filetype);
+
+    let filename = cfg_path
+        .filename
+        .unwrap_or(OsStr::new("config").to_os_string());
+    let filetype = cfg_path
+        .extension
+        .unwrap_or(OsStr::new("toml").to_os_string());
+
+    let filename = filename.into_string().unwrap();
+    let filetype = filetype.into_string().unwrap();
+
+    let pkg_name = env!("CARGO_PKG_NAME");
+    let project = ProjectDirs::from("rs", "", pkg_name).unwrap();
+    let default_dir = project.config_dir();
+    let config_dir = cfg_path.parent.as_deref().unwrap_or(default_dir);
+
+    let tip = Path::new(&filename).with_extension(&filetype);
+    let config_file = [config_dir, tip.as_ref()]
+        .iter()
+        .collect::<PathBuf>()
+        .into_os_string()
+        .into_string()
+        .unwrap();
+    let parent: String = config_dir.to_str().unwrap().into();
+
+    let (ser, ser_fn) = pick_serializer(&filetype);
 
     let gen = quote! {
-        use ::fondant::{ ProjectDirs, toml, serde_json, serde_yaml, FondantError };
-        use ::std::path::{ Path, PathBuf };
+        use ::fondant::{Configure, ProjectDirs, toml, serde_json, serde_yaml, FondantError};
         use ::std::option::Option;
         use ::std::fs::{self, File, OpenOptions};
         use ::std::io::prelude::*;
         use ::std::io::{ ErrorKind::NotFound, Write };
+        use ::std::ffi::{OsStr, OsString};
+        use ::std::path::{Path, PathBuf};
 
-        impl Config for #struct_ident {
+        impl Configure for #struct_ident {
             fn load() -> Result<#struct_ident, FondantError> {
-                let project = ProjectDirs::from("rs", "", #struct_name).ok_or(FondantError::InvalidHomeDir)?;
-                let config_dir = project.config_dir();
-
-                let tip = (Path::new(#filename)).with_extension(&#filetype);
-                let config_file: PathBuf = [config_dir, &tip].iter().collect();
-
-                match File::open(&config_file) {
+                match File::open(&#config_file) {
                     Ok(mut cfg) => {
-                        // the file exists, parse the toml and return the struct
                         let mut cfg_data = String::new();
                         cfg.read_to_string(&mut cfg_data);
 
@@ -93,26 +125,20 @@ fn gen_impl(ast: &DeriveInput, filename: String, filetype: String) -> TokenStrea
                         return Ok(config);
                     },
                     Err(ref e) if e.kind() == NotFound => {
-                        fs::create_dir_all(project.config_dir());
+                        fs::create_dir_all(#parent).map_err(FondantError::DirCreateErr)?;
                         let default_impl = #struct_ident::default();
-                        Config::store(&default_impl)?;
+                        Configure::store(&default_impl)?;
                         return Ok(default_impl);
                     },
                     Err(e) => return Err(FondantError::LoadError),
                 };
             }
             fn store(&self) -> Result<(), FondantError> {
-                let project = ProjectDirs::from("rs", "", #struct_name).ok_or(FondantError::InvalidHomeDir)?;
-                let config_dir = project.config_dir();
-
-                let tip = (Path::new(#filename)).with_extension(&#filetype);
-                let config_file: PathBuf = [config_dir, &tip].iter().collect();
-
                 let mut f = OpenOptions::new()
                     .write(true)
                     .create(true)
                     .truncate(true)
-                    .open(config_file)
+                    .open(#config_file)
                     .map_err(|_| FondantError::FileOpenError)?;
 
                 let s = #ser::#ser_fn(self).map_err(|_| FondantError::ConfigParseError)?;