feat: add customizable terminators (#15)

While using `cargo-get` in scripts, it is often useful to be able to
change the ending character of the output -- ensuring that a newline
does *not* get printed, adding a NUL terminator, etc.

This commit adds an option `--terminator` which changes the terminator
that is printed after the requested output from `cargo-get`.

Signed-off-by: vados <[email protected]>

src/cli.rs

@@ -2,7 +2,7 @@ use std::{error::Error, path::PathBuf};
 
 use clap::{Args, Parser, Subcommand};
 
-use crate::delimiter::Delimiter;
+use crate::{delimiter::Delimiter, terminator::Terminator};
 
 #[derive(Parser)]
 #[command(author, version, about, long_about = None)]
@@ -25,6 +25,14 @@ pub struct Cli {
         help = "Delimiter for array values"
     )]
     pub delimiter: Option<Delimiter>,
+
+    #[clap(
+        global = true,
+        long,
+        value_name = "CR | LF | CRLF | Nul | String",
+        help = "String terminator for the output that is returned"
+    )]
+    pub terminator: Option<Terminator>,
 }
 
 #[derive(Args, Clone)]

src/main.rs

@@ -1,33 +1,36 @@
 mod cli;
 mod delimiter;
 mod error;
+mod terminator;
 
 use cargo_toml::Manifest;
 use clap::Parser;
 use delimiter::Delimiter;
 use error::NotSpecified;
 use std::{error::Error, path::PathBuf};
+use terminator::Terminator;
 
 fn main() -> Result<(), Box<dyn Error>> {
     let mut args: Vec<_> = std::env::args().collect();
 
-    if args.get(1) == Some(&"get".to_owned()) {
+    if let Some("get") = args.get(1).map(String::as_ref) {
         args.remove(1);
     }
 
     let cli = cli::Cli::parse_from(args);
 
     match output(cli) {
-        Ok(out) => println!("{}", out),
+        Ok(out) => print!("{out}"),
         Err(err) => {
-            eprintln!("Error: {}", err);
+            eprintln!("Error: {err}");
             std::process::exit(1);
         }
     }
 
     Ok(())
 }
 
+/// Generate output string that will be printed to the console
 pub fn output(cli: cli::Cli) -> Result<String, Box<dyn Error>> {
     let entry_point = match cli.entry.clone() {
         Some(p) => p,
@@ -48,8 +51,9 @@ pub fn output(cli: cli::Cli) -> Result<String, Box<dyn Error>> {
 
     let delimiter: Delimiter = cli.delimiter.unwrap_or_default();
     let delim_string = delimiter.to_string();
+    let terminator: Terminator = cli.terminator.unwrap_or_default();
 
-    let output = match cli.command {
+    let mut output = match cli.command {
         cli::Command::PackageVersion { inner } => {
             let v: semver::Version = package()?.version().parse()?;
             inner.match_version(v, &delimiter)?
@@ -225,9 +229,12 @@ pub fn output(cli: cli::Cli) -> Result<String, Box<dyn Error>> {
             .to_string(),
     };
 
+    output.push_str(terminator.to_string().as_ref());
+
     Ok(output)
 }
 
+/// Search the given directory for Cargo.toml, recursively searching upwards
 fn search_manifest_path(dir: &std::path::Path) -> Option<PathBuf> {
     let manifest = dir.join("Cargo.toml");
 

src/terminator.rs

@@ -0,0 +1,73 @@
+use std::fmt;
+
+#[derive(Debug, PartialEq, Clone, Default)]
+pub enum Terminator {
+    Cr,
+    CrLf,
+    #[default]
+    Lf,
+    Nul,
+    String(String),
+}
+
+impl fmt::Display for Terminator {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str(match self {
+            Self::Cr => "\r",
+            Self::CrLf => "\r\n",
+            Self::Lf => "\n",
+            Self::Nul => "\0",
+            Self::String(s) => s,
+        })
+    }
+}
+
+impl std::str::FromStr for Terminator {
+    type Err = std::convert::Infallible;
+
+    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
+        match s.to_lowercase().as_ref() {
+            "cr" => Ok(Self::Cr),
+            "crlf" => Ok(Self::CrLf),
+            "lf" => Ok(Self::Lf),
+            "nul" => Ok(Self::Nul),
+            _ => Ok(Self::String(s.to_owned())),
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn display_ok() {
+        let res = format!(
+            "{} {} {} {} {}",
+            Terminator::Cr,
+            Terminator::CrLf,
+            Terminator::Lf,
+            Terminator::Nul,
+            Terminator::String("abc!@#$%^&*()".to_owned())
+        );
+
+        let expected = "\r \r\n \n \0 abc!@#$%^&*()".to_owned();
+
+        assert_eq!(res, expected);
+    }
+
+    #[test]
+    fn parse_ok() -> Result<(), Box<dyn std::error::Error>> {
+        for (input, result) in [
+            ("Cr", Terminator::Cr),
+            ("CrLf", Terminator::CrLf),
+            ("Lf", Terminator::Lf),
+            ("Nul", Terminator::Nul),
+        ] {
+            assert_eq!(input.parse::<Terminator>()?, result);
+            assert_eq!(input.to_lowercase().parse::<Terminator>()?, result);
+            assert_eq!(input.to_uppercase().parse::<Terminator>()?, result);
+        }
+        Ok(())
+    }
+}

tests/terminator.rs

@@ -0,0 +1,74 @@
+use assert_cmd::Command;
+use predicates::prelude::*;
+
+#[test]
+fn pkg_name_with_custom_terminator() {
+    let mut cmd = Command::cargo_bin("cargo-get").unwrap();
+    let p = std::fs::canonicalize("tests/data/toml_02").unwrap();
+    cmd.current_dir(p);
+
+    let assert = cmd.arg("package.name").arg("--terminator=.exe").assert();
+    assert
+        .success()
+        .stdout(predicate::eq(b"test-name.exe" as &[u8]));
+}
+
+#[test]
+fn pkg_name_with_cr_as_terminator() {
+    let mut cmd = Command::cargo_bin("cargo-get").unwrap();
+    let p = std::fs::canonicalize("tests/data/toml_02").unwrap();
+    cmd.current_dir(p);
+
+    let assert = cmd.arg("package.name").arg("--terminator=cr").assert();
+    assert
+        .success()
+        .stdout(predicate::eq(b"test-name\r" as &[u8]));
+}
+
+#[test]
+fn pkg_name_with_lf_as_terminator() {
+    let mut cmd = Command::cargo_bin("cargo-get").unwrap();
+    let p = std::fs::canonicalize("tests/data/toml_02").unwrap();
+    cmd.current_dir(p);
+
+    let assert = cmd.arg("package.name").arg("--terminator=lf").assert();
+    assert
+        .success()
+        .stdout(predicate::eq(b"test-name\n" as &[u8]));
+}
+
+#[test]
+fn pkg_name_with_crlf_as_terminator() {
+    let mut cmd = Command::cargo_bin("cargo-get").unwrap();
+    let p = std::fs::canonicalize("tests/data/toml_02").unwrap();
+    cmd.current_dir(p);
+
+    let assert = cmd.arg("package.name").arg("--terminator=crlf").assert();
+    assert
+        .success()
+        .stdout(predicate::eq(b"test-name\r\n" as &[u8]));
+}
+
+#[test]
+fn pkg_name_with_semicolon_as_terminator() {
+    let mut cmd = Command::cargo_bin("cargo-get").unwrap();
+    let p = std::fs::canonicalize("tests/data/toml_02").unwrap();
+    cmd.current_dir(p);
+
+    let assert = cmd.arg("package.name").arg("--terminator=;").assert();
+    assert
+        .success()
+        .stdout(predicate::eq(b"test-name;" as &[u8]));
+}
+
+#[test]
+fn pkg_name_with_nul_as_terminator() {
+    let mut cmd = Command::cargo_bin("cargo-get").unwrap();
+    let p = std::fs::canonicalize("tests/data/toml_02").unwrap();
+    cmd.current_dir(p);
+
+    let assert = cmd.arg("package.name").arg("--terminator=nul").assert();
+    assert
+        .success()
+        .stdout(predicate::eq(b"test-name\0" as &[u8]));
+}