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jj/cli/testing/fake-formatter.rs

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Rust

// Copyright 2024 The Jujutsu Authors
//
// 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.
use std::fs::OpenOptions;
use std::io::Write;
use std::path::PathBuf;
use std::process::ExitCode;
use clap::arg;
use clap::Parser;
use itertools::Itertools;
/// A fake code formatter, useful for testing
///
/// `fake-formatter` is similar to `cat`.
/// `fake-formatter --reverse` is similar to `rev` (not `tac`).
/// `fake-formatter --stdout foo` is similar to `echo foo`.
/// `fake-formatter --stdout foo --stderr bar --fail` is similar to
/// `echo foo; echo bar >&2; false`.
/// `fake-formatter --tee foo` is similar to `tee foo`).
///
/// This program acts as a portable alternative to that class of shell commands.
#[derive(Parser, Debug)]
struct Args {
/// Exit with non-successful status.
#[arg(long, default_value_t = false)]
fail: bool,
/// Reverse the characters in each line when reading stdin.
#[arg(long, default_value_t = false)]
reverse: bool,
/// Convert all characters to uppercase when reading stdin.
#[arg(long, default_value_t = false)]
uppercase: bool,
/// Convert all characters to lowercase when reading stdin.
#[arg(long, default_value_t = false)]
lowercase: bool,
/// Adds a line to the end of the file
#[arg(long)]
append: Option<String>,
/// Write this string to stdout, and ignore stdin.
#[arg(long)]
stdout: Option<String>,
/// Write this string to stderr.
#[arg(long)]
stderr: Option<String>,
/// Duplicate stdout into this file.
#[arg(long)]
tee: Option<PathBuf>,
}
fn main() -> ExitCode {
let args: Args = Args::parse();
// Code formatters tend to print errors before printing the result.
if let Some(data) = args.stderr {
eprint!("{}", data);
}
let stdout = if let Some(data) = args.stdout {
// Other content-altering flags don't apply to --stdout.
assert!(!args.reverse);
assert!(!args.uppercase);
assert!(!args.lowercase);
assert!(args.append.is_none());
data
} else {
let mut stdout = std::io::stdin()
.lines()
.map(|line| {
format!("{}\n", {
let line = if args.reverse {
line.unwrap().chars().rev().collect()
} else {
line.unwrap()
};
if args.uppercase {
assert!(!args.lowercase);
line.to_uppercase()
} else if args.lowercase {
assert!(!args.uppercase);
line.to_lowercase()
} else {
line
}
})
})
.join("");
if let Some(line) = args.append {
stdout.push_str(&line);
}
stdout
};
print!("{}", stdout);
if let Some(path) = args.tee {
let mut file = OpenOptions::new()
.create(true)
.append(true)
.open(path)
.unwrap();
write!(file, "{}", stdout).unwrap();
}
if args.fail {
ExitCode::FAILURE
} else {
ExitCode::SUCCESS
}
}