main.rs

use std::{fs::File, io::BufReader, path::PathBuf};

use anyhow::Result;
use serde_json::Value;
use structopt::StructOpt;

#[derive(Debug, StructOpt)]
#[structopt()]
struct Opt {
    path: PathBuf,

    #[structopt(short, long)]
    buffer: bool,

    #[structopt(long)]
    buffer_size: Option<usize>,
}

fn main() -> Result<()> {
    let opt = Opt::from_args();
    let file = File::open(opt.path)?;
    let content: Value = match (opt.buffer, opt.buffer_size) {
        (false, _) => serde_json::from_reader(file)?,
        (true, None) => serde_json::from_reader(BufReader::new(file))?,
        (true, Some(n)) => serde_json::from_reader(BufReader::with_capacity(n, file))?,
    };
    dbg!(content.is_object());
    Ok(())
}