1 files changed, 167 insertions, 0 deletions
diff --git a/var/shell-complete.rs b/var/shell-complete.rs
new file mode 100644
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--- /dev/null
+++ b/var/shell-complete.rs
@@ -0,0 +1,167 @@
+// shell-complete.rs
+
+// *************************************************************************
+// * Copyright (C) 2020 Daniel Mueller (deso@posteo.net)                   *
+// *                                                                       *
+// * This program is free software: you can redistribute it and/or modify  *
+// * it under the terms of the GNU General Public License as published by  *
+// * the Free Software Foundation, either version 3 of the License, or     *
+// * (at your option) any later version.                                   *
+// *                                                                       *
+// * This program is distributed in the hope that it will be useful,       *
+// * but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+// * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+// * GNU General Public License for more details.                          *
+// *                                                                       *
+// * You should have received a copy of the GNU General Public License     *
+// * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
+// *************************************************************************
+
+use std::io;
+
+use structopt::clap;
+use structopt::StructOpt as _;
+
+#[allow(unused)]
+mod nitrocli {
+  include!("../src/arg_util.rs");
+
+  // We only need a stripped down version of the `Command` macro.
+  macro_rules! Command {
+    ( $(#[$docs:meta])* $name:ident, [
+      $( $(#[$doc:meta])* $var:ident$(($inner:ty))? => $exec:expr, ) *
+    ] ) => {
+      $(#[$docs])*
+      #[derive(Debug, PartialEq, structopt::StructOpt)]
+      pub enum $name {
+        $(
+          $(#[$doc])*
+          $var$(($inner))?,
+        )*
+      }
+    };
+  }
+
+  include!("../src/args.rs");
+}
+
+/// Generate a bash completion script for nitrocli.
+///
+/// The script will be emitted to standard output.
+#[derive(Debug, structopt::StructOpt)]
+pub struct Args {
+  /// The command for which to generate the bash completion script.
+  #[structopt(default_value = "nitrocli")]
+  pub command: String,
+}
+
+fn generate_bash<W>(command: &str, output: &mut W)
+where
+  W: io::Write,
+{
+  let mut app = nitrocli::Args::clap();
+  app.gen_completions_to(command, clap::Shell::Bash, output);
+}
+
+fn main() {
+  let args = Args::from_args();
+  generate_bash(&args.command, &mut io::stdout())
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  use std::io;
+  use std::ops::Add as _;
+  use std::process;
+
+  /// Separate the given words by newlines.
+  fn lines<'w, W>(mut words: W) -> String
+  where
+    W: Iterator<Item = &'w str>,
+  {
+    let first = words.next().unwrap_or("");
+    words
+      .fold(first.to_string(), |words, word| {
+        format!("{}\n{}", words, word)
+      })
+      .add("\n")
+  }
+
+  /// Check if `bash` is present on the system.
+  fn has_bash() -> bool {
+    match process::Command::new("bash").arg("-c").arg("exit").spawn() {
+      // We deliberately only indicate that bash does not exist if we
+      // get a file-not-found error. We don't expect any other error but
+      // should there be one things will blow up later.
+      Err(ref err) if err.kind() == io::ErrorKind::NotFound => false,
+      _ => true,
+    }
+  }
+
+  /// Perform a bash completion of the given arguments to nitrocli.
+  fn complete_bash<'w, W>(words: W) -> Vec<u8>
+  where
+    W: ExactSizeIterator<Item = &'w str>,
+  {
+    let mut buffer = Vec::new();
+    generate_bash("nitrocli", &mut buffer);
+
+    let script = String::from_utf8(buffer).unwrap();
+    let command = format!(
+      "
+set -e;
+eval '{script}';
+export COMP_WORDS=({words});
+export COMP_CWORD={index};
+_nitrocli;
+echo -n ${{COMPREPLY}}
+      ",
+      index = words.len(),
+      words = lines(Some("nitrocli").into_iter().chain(words)),
+      script = script
+    );
+
+    let output = process::Command::new("bash")
+      .arg("-c")
+      .arg(command)
+      .output()
+      .unwrap();
+
+    output.stdout
+  }
+
+  #[test]
+  fn array_lines() {
+    assert_eq!(&lines(vec![].into_iter()), "\n");
+    assert_eq!(&lines(vec!["first"].into_iter()), "first\n");
+    assert_eq!(
+      &lines(vec!["first", "second"].into_iter()),
+      "first\nsecond\n"
+    );
+    assert_eq!(
+      &lines(vec!["first", "second", "third"].into_iter()),
+      "first\nsecond\nthird\n"
+    );
+  }
+
+  #[test]
+  fn complete_all_the_things() {
+    if !has_bash() {
+      return;
+    }
+
+    assert_eq!(complete_bash(vec!["stat"].into_iter()), b"status");
+    assert_eq!(
+      complete_bash(vec!["status", "--ver"].into_iter()),
+      b"--version"
+    );
+    assert_eq!(complete_bash(vec!["--version"].into_iter()), b"--version");
+    assert_eq!(complete_bash(vec!["--model", "s"].into_iter()), b"storage");
+    assert_eq!(
+      complete_bash(vec!["otp", "get", "--model", "p"].into_iter()),
+      b"pro"
+    );
+  }
+}