[#110] Introduces the OS enum and improves one error message (#124)

Resolves #110

This PR adds the `OS` enum and updates `AssetName` logic to use it
instead of `env::consts::OS`.

It also improves a single error message to display `Specify
'asset_name.{get_current_os()}'` in it.

CHANGELOG.md

@@ -17,6 +17,9 @@ available [on GitHub][2].
 * [#111](https://github.com/chshersh/tool-sync/issues/111):
   Adds repo URLs to the output of `default-config` and `install` commands
   (by [@crudiedo][crudiedo])
+* [#110](https://github.com/chshersh/tool-sync/issues/110):
+  Adds the 'OS' enum and improves error messages
+  (by [@crudiedo][crudiedo])
 
 ### Fixed
 

src/config/toml.rs

@@ -7,6 +7,7 @@ use toml::{map::Map, Value};
 use crate::config::schema::{Config, ConfigAsset};
 use crate::infra::err;
 use crate::model::asset_name::AssetName;
+use crate::model::os::OS;
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum TomlError {
@@ -99,9 +100,9 @@ fn decode_asset_name(table: &Map<String, Value>) -> AssetName {
         },
 
         Some(table) => {
-            let linux = str_by_key(table, "linux");
-            let macos = str_by_key(table, "macos");
-            let windows = str_by_key(table, "windows");
+            let linux = str_by_key(table, &OS::Linux.to_string());
+            let macos = str_by_key(table, &OS::MacOS.to_string());
+            let windows = str_by_key(table, &OS::Windows.to_string());
 
             AssetName {
                 linux,

src/model.rs

@@ -1,3 +1,4 @@
 pub mod asset_name;
+pub mod os;
 pub mod release;
 pub mod tool;

src/model/asset_name.rs

@@ -1,4 +1,4 @@
-use std::env;
+use crate::model::os::{get_current_os, OS};
 
 /// Part of the name for each OS to identify proper asset
 #[derive(Debug, PartialEq, Eq)]
@@ -9,17 +9,13 @@ pub struct AssetName {
 }
 
 impl AssetName {
-    /// Get the current OS where the 'tool-sync' is running and extract the
-    /// corresponding name of the downloaded tool
-    ///
-    /// !!! WARNING !!! This function uses OS of the system where 'tool-sync' was
-    /// compiled. The function relies on the assumption that a user will run e.g.
-    /// the macOS executable on macOS
+    /// Get the current OS and extract the corresponding name
+    /// of the downloaded tool
     pub fn get_name_by_os(&self) -> Option<&String> {
-        match env::consts::OS {
-            "windows" => self.windows.as_ref(),
-            "macos" => self.macos.as_ref(),
-            _ => self.linux.as_ref(),
+        match get_current_os() {
+            OS::Windows => self.windows.as_ref(),
+            OS::MacOS => self.macos.as_ref(),
+            OS::Linux => self.linux.as_ref(),
         }
     }
 }

src/model/os.rs

@@ -0,0 +1,63 @@
+use std::env;
+use std::fmt::{Display, Formatter};
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum OS {
+    Windows,
+    MacOS,
+    Linux,
+}
+
+/// Return the current OS where the 'tool-sync' is running
+///
+/// !!! WARNING !!! This function uses OS of the system where 'tool-sync' was
+/// compiled. The function relies on the assumption that a user will run e.g.
+/// the macOS executable on macOS
+pub fn get_current_os() -> OS {
+    match env::consts::OS {
+        "windows" => OS::Windows,
+        "macos" => OS::MacOS,
+        _ => OS::Linux,
+    }
+}
+
+impl Display for OS {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Windows => {
+                write!(f, "windows")
+            }
+            Self::MacOS => {
+                write!(f, "macos")
+            }
+            Self::Linux => {
+                write!(f, "linux")
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn current_os() {
+        let os = get_current_os();
+
+        if cfg!(target_os = "windows") {
+            assert_eq!(os, OS::Windows);
+        } else if cfg!(target_os = "macos") {
+            assert_eq!(os, OS::MacOS);
+        } else {
+            assert_eq!(os, OS::Linux);
+        }
+    }
+
+    #[test]
+    fn os_display() {
+        assert_eq!(OS::Windows.to_string(), String::from("windows"));
+        assert_eq!(OS::MacOS.to_string(), String::from("macos"));
+        assert_eq!(OS::Linux.to_string(), String::from("linux"));
+    }
+}

src/model/release.rs

@@ -1,8 +1,8 @@
 use serde::Deserialize;
-use std::env;
 use std::fmt::{Display, Formatter, Write};
 
 use crate::infra::err;
+use crate::model::os::get_current_os;
 
 #[derive(Deserialize, Debug)]
 pub struct Release {
@@ -35,8 +35,8 @@ impl Display for AssetError {
             Self::OsSelectorUnknown => {
                 write!(
                     f,
-                    "Unknown asset selector for OS: {}. Specify 'asset_name.your_os' in the cofig.",
-                    env::consts::OS
+                    "Unknown asset selector for the current OS. Specify 'asset_name.{}' in the config.",
+                    get_current_os()
                 )
             }
             Self::NotFound(asset_name) => {