From fcd59ace3a41e97328079d95c052a0570733f75c Mon Sep 17 00:00:00 2001
From: Vladyslav Tronko <git@vtronko.me>
Date: Tue, 14 Mar 2023 19:39:57 +0200
Subject: [PATCH] Fix chmln#100: allow line-buffered input

---
 src/cli.rs   |  4 ++++
 src/input.rs | 31 +++++++++++++++++++++++++++++++
 src/main.rs  |  2 ++
 3 files changed, 37 insertions(+)

diff --git a/src/cli.rs b/src/cli.rs
index ab092db..2636f03 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -19,6 +19,10 @@ pub(crate) struct Options {
     /// Recursively replace files
     pub recursive: bool,
 
+    #[structopt(short = "l", long = "line-buffered-mode")]
+    /// Buffered mode. Doesn't support multiline matching
+    pub line_buffered: bool,
+
     #[structopt(short = "n")]
     /// Limit the number of replacements
     pub replacements: Option<usize>,
diff --git a/src/input.rs b/src/input.rs
index 9751a6d..762b395 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -1,9 +1,11 @@
 use crate::{Replacer, Result};
+use std::io::{BufRead, Write};
 use std::{fs::File, io::prelude::*, path::PathBuf};
 
 #[derive(Debug)]
 pub(crate) enum Source {
     Stdin,
+    StdinLineBuffered,
     Files(Vec<PathBuf>),
 }
 
@@ -54,6 +56,35 @@ impl App {
 
                 Ok(())
             }
+            (Source::StdinLineBuffered, _) => {
+                let stdin = std::io::stdin();
+                let stdout = std::io::stdout();
+                let mut handle = stdout.lock();
+
+                let mut buffer = String::new();
+
+                loop {
+                    let bytes_read = stdin
+                        .lock()
+                        .read_line(&mut buffer)
+                        .expect("Error reading from standard input");
+                    if bytes_read == 0 {
+                        break;
+                    }
+                    let output = if is_tty {
+                        self.replacer.replace_preview(buffer.as_bytes())
+                    } else {
+                        self.replacer.replace(buffer.as_bytes())
+                    };
+                    handle
+                        .write_all(output.as_ref())
+                        .expect("Error writing to standard output");
+                    handle.flush().expect("Error flushing output");
+                    buffer.clear();
+                }
+
+                Ok(())
+            }
             (Source::Files(paths), false) => {
                 use rayon::prelude::*;
 
diff --git a/src/main.rs b/src/main.rs
index 436904a..ea6638b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,6 +16,8 @@ fn main() -> Result<()> {
         Source::recursive()?
     } else if options.files.len() > 0 {
         Source::Files(options.files)
+    } else if options.line_buffered {
+        Source::StdinLineBuffered
     } else {
         Source::Stdin
     };