Use LineWriter when input is stdin (#10)

src/choice.rs

@@ -1,5 +1,4 @@
 use std::convert::TryInto;
-use std::io::{BufWriter, Write};
 use std::iter::FromIterator;
 
 use crate::config::Config;
@@ -36,12 +35,7 @@ impl Choice {
         }
     }
 
-    pub fn print_choice<W: Write>(
-        &self,
-        line: &String,
-        config: &Config,
-        handle: &mut BufWriter<W>,
-    ) {
+    pub fn print_choice<W: WriteReceiver>(&self, line: &String, config: &Config, handle: &mut W) {
         if config.opt.character_wise {
             let line_chars = line[0..line.len() - 1].chars();
             self.print_choice_generic(line_chars, config, handle);
@@ -62,10 +56,10 @@ impl Choice {
         self.negative_index
     }
 
-    fn print_choice_generic<W, T, I>(&self, mut iter: I, config: &Config, handle: &mut BufWriter<W>)
+    fn print_choice_generic<W, T, I>(&self, mut iter: I, config: &Config, handle: &mut W)
     where
-        W: Write,
-        T: Writeable + Copy,
+        W: WriteReceiver,
+        T: Writeable,
         I: Iterator<Item = T>,
     {
         if self.is_reverse_range() && !self.has_negative_index() {
@@ -81,23 +75,14 @@ impl Choice {
         }
     }
 
-    fn print_choice_loop<W, T, I>(iter: I, config: &Config, handle: &mut BufWriter<W>)
-    where
-        W: Write,
-        T: Writeable + Copy,
-        I: Iterator<Item = T>,
-    {
-        Choice::print_choice_loop_max_items(iter, config, handle, isize::max_value());
-    }
-
     fn print_choice_loop_max_items<W, T, I>(
         iter: I,
         config: &Config,
-        handle: &mut BufWriter<W>,
+        handle: &mut W,
         max_items: isize,
     ) where
-        W: Write,
-        T: Writeable + Copy,
+        W: WriteReceiver,
+        T: Writeable,
         I: Iterator<Item = T>,
     {
         let mut peek_iter = iter.peekable();
@@ -111,10 +96,10 @@ impl Choice {
         }
     }
 
-    fn print_choice_negative<W, T, I>(&self, iter: I, config: &Config, handle: &mut BufWriter<W>)
+    fn print_choice_negative<W, T, I>(&self, iter: I, config: &Config, handle: &mut W)
     where
-        W: Write,
-        T: Writeable + Copy,
+        W: WriteReceiver,
+        T: Writeable,
         I: Iterator<Item = T>,
     {
         let vec = Vec::from_iter(iter);
@@ -136,10 +121,10 @@ impl Choice {
         }
     }
 
-    fn print_choice_reverse<W, T, I>(&self, mut iter: I, config: &Config, handle: &mut BufWriter<W>)
+    fn print_choice_reverse<W, T, I>(&self, mut iter: I, config: &Config, handle: &mut W)
     where
-        W: Write,
-        T: Writeable + Copy,
+        W: WriteReceiver,
+        T: Writeable,
         I: Iterator<Item = T>,
     {
         if self.end > 0 {

src/main.rs

@@ -1,5 +1,5 @@
 use std::fs::File;
-use std::io::{self, Read, Write};
+use std::io::{self, Read};
 use std::process;
 use structopt::StructOpt;
 
@@ -22,6 +22,16 @@ use writer::WriteReceiver;
 
 fn main() {
     let opt = Opt::from_args();
+
+    let stdout = io::stdout();
+    let lock = stdout.lock();
+    match opt.input {
+        Some(_) => main_generic(opt, &mut io::BufWriter::new(lock)),
+        None => main_generic(opt, &mut io::LineWriter::new(lock)),
+    }
+}
+
+fn main_generic<W: WriteReceiver>(opt: Opt, handle: &mut W) {
     let config = Config::new(opt);
 
     let read = match &config.opt.input {
@@ -39,16 +49,12 @@ fn main() {
     let mut reader = reader::BufReader::new(read);
     let mut buffer = String::new();
 
-    let stdout = io::stdout();
-    let lock = stdout.lock();
-    let mut handle = io::BufWriter::new(lock);
-
     while let Some(line) = reader.read_line(&mut buffer) {
         match line {
             Ok(l) => {
                 let choice_iter = &mut config.opt.choices.iter().peekable();
                 while let Some(choice) = choice_iter.next() {
-                    choice.print_choice(&l, &config, &mut handle);
+                    choice.print_choice(&l, &config, handle);
                     if choice_iter.peek().is_some() {
                         handle.write_separator(&config);
                     }

src/writeable.rs

@@ -1,4 +1,4 @@
-pub trait Writeable {
+pub trait Writeable: Copy {
     fn to_byte_buf(&self) -> Box<[u8]>;
 }
 

src/writer.rs

@@ -1,14 +1,9 @@
-use std::io::{BufWriter, Write};
+use std::io::{BufWriter, LineWriter, Write};
 
 use crate::config::Config;
 use crate::writeable::Writeable;
 
-pub trait WriteReceiver {
-    fn write_choice<Wa: Writeable>(&mut self, b: Wa, config: &Config, print_separator: bool);
-    fn write_separator(&mut self, config: &Config);
-}
-
-impl<W: Write> WriteReceiver for BufWriter<W> {
+pub trait WriteReceiver: Write {
     fn write_choice<Wa: Writeable>(&mut self, b: Wa, config: &Config, print_separator: bool) {
         let num_bytes_written = match self.write(&b.to_byte_buf()) {
             Ok(x) => x,
@@ -29,3 +24,7 @@ impl<W: Write> WriteReceiver for BufWriter<W> {
         }
     }
 }
+
+impl<W: Write> WriteReceiver for BufWriter<W> {}
+
+impl<W: Write> WriteReceiver for LineWriter<W> {}