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/*
* Copyright 2019 The Starlark in Rust Authors.
* Copyright (c) Facebook, Inc. and its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// This is not public API, but it is used by Starlark command line utility.
#![doc(hidden)]
#[cfg(not(target_arch = "wasm32"))]
mod with_or_without_rustyline {
use std::env;
use std::io;
use rustyline::error::ReadlineError;
use rustyline::history::DefaultHistory;
use rustyline::Editor;
/// Wrapper for the readline library, whichever we are using at the moment.
pub struct ReadLine {
editor: Editor<(), DefaultHistory>,
histfile: Option<String>,
}
impl ReadLine {
pub fn new(histfile_env: &str) -> anyhow::Result<ReadLine> {
let mut editor = Editor::new()?;
let histfile = if let Ok(histfile) = env::var(histfile_env) {
if let Err(e) = editor.load_history(&histfile) {
match e {
ReadlineError::Io(e) if e.kind() == io::ErrorKind::NotFound => {}
e => eprintln!("Failed to load history from `{}`: {}", histfile, e),
}
}
Some(histfile)
} else {
None
};
Ok(ReadLine { editor, histfile })
}
/// Read line. Return `None` on EOF or interrupt.
pub fn read_line(&mut self, prompt: &str) -> anyhow::Result<Option<String>> {
match self.editor.readline(prompt) {
Ok(line) => {
self.editor.add_history_entry(line.as_str())?;
if let Some(histfile) = &self.histfile {
if let Err(e) = self.editor.save_history(&histfile) {
eprintln!("Failed to save history to `{}`: {}", histfile, e);
}
}
Ok(Some(line))
}
// User pressed EOF - disconnected terminal, or similar
Err(ReadlineError::Interrupted) | Err(ReadlineError::Eof) => Ok(None),
Err(e) => Err(e.into()),
}
}
}
}
#[cfg(target_arch = "wasm32")]
mod with_or_without_rustyline {
#[derive(thiserror::Error, Debug)]
#[error("Rustyline is not supported on wasm32")]
struct NoRustyline;
pub struct ReadLine(());
impl ReadLine {
pub fn new(_histfile_env: &str) -> anyhow::Result<ReadLine> {
Err(NoRustyline.into())
}
pub fn read_line(&mut self, _prompt: &str) -> anyhow::Result<Option<String>> {
Err(NoRustyline.into())
}
}
}
pub use with_or_without_rustyline::ReadLine;