Another ugly commit, tweak handling of input

Cargo.lock

@@ -15,11 +15,6 @@ name = "cfg-if"
 version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
-[[package]]
-name = "lazy_static"
-version = "1.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
 [[package]]
 name = "libc"
 version = "0.2.62"
@@ -42,15 +37,6 @@ name = "rs-kilo"
 version = "0.1.0"
 dependencies = [
  "nix 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "term-parser 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "term-parser"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -62,8 +48,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3d155346769a6855b86399e9bc3814ab343cd3d62c7e985113d46a0ec3c281fd"
 "checksum cc 1.0.40 (registry+https://github.com/rust-lang/crates.io-index)" = "b548a4ee81fccb95919d4e22cfea83c7693ebfd78f0495493178db20b3139da7"
 "checksum cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "b486ce3ccf7ffd79fdeb678eac06a9e6c09fc88d33836340becb8fffe87c5e33"
-"checksum lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bc5729f27f159ddd61f4df6228e827e86643d4d3e7c32183cb30a1c08f604a14"
 "checksum libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)" = "34fcd2c08d2f832f376f4173a231990fa5aef4e99fb569867318a227ef4c06ba"
 "checksum nix 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3b2e0b4f3320ed72aaedb9a5ac838690a8047c7b275da22711fddff4f8a14229"
-"checksum term-parser 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3c483a684059c71636d0e4ff927bd5feb5f2a533e7a8f16a0008dd33c8752cbc"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"

Cargo.toml

@@ -7,5 +7,5 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+# Rust wrappers for C/POSIX headers
 nix = "0.15.0"
-term-parser = "0.2.0"

src/editor.rs

@@ -9,18 +9,15 @@ use std::io::prelude::*;
 use std::io::{BufReader, Error, Stdin};
 use std::str::Chars;
 
-use term_parser::{Action, ActionIter};
-
 /// Main structure for the editor
-pub struct Editor {
-
-}
+///
+/// impl blocks are split similarly to the original C implementation
+pub struct Editor {}
 
 // init
 impl Editor {
     pub fn new() -> Self {
-        Editor {
-        }
+        Editor {}
     }
 }
 
@@ -28,8 +25,9 @@ impl Editor {
 impl Editor {
     fn read_key(&mut self) -> Option<Vec<char>> {
         let stdin = io::stdin();
+        let stdin = stdin.lock();
         let mut in_str = String::new();
-        let mut input = BufReader::new(stdin.take(1));
+        let mut input = BufReader::with_capacity(3, stdin);
         input.read_to_string(&mut in_str).unwrap();
 
         let mut output: Vec<char> = vec![];
@@ -39,68 +37,44 @@ impl Editor {
         }
 
         if output.len() == 0 {
-            return None
+            return None;
         }
 
-        return Some(output)
-    }
-
-    fn read_term_code(&mut self) -> ActionIter<BufReader<Stdin>> {
-        let stdin = io::stdin();
-        let buffer = BufReader::new(stdin);
-        let term_code_iter = ActionIter::new(buffer);
-
-        /*
-        for term_code in self.read_term_code() {
-            let term_code = match term_code {
-                Ok(code) => code,
-                Err(e) => panic!("{:?}\r\n", e),
-            };
-            print!("{:?}\r\n", term_code);
-        }
-        */
-
-        term_code_iter
+        return Some(output);
     }
 }
 
 // Input
 impl Editor {
     pub fn process_keypress(&mut self) -> Option<()> {
-        let chars= self.read_key();
+        match self.read_key() {
+            // Just continue the input loop on an "empty" keypress
+            None => Some(()),
+            Some(chars) => {
+                let first = chars[0];
 
-        // No input, just continue
-        if chars.is_none() {
-            return Some(())
-        }
-        let chars = chars.unwrap();
-
-        if chars.len() == 1 {
-            let char = chars[0];
-
-            if char == CTRL_KEY('q') {
+                if first == ctrl_key('q') {
                     // Break out of the input loop
                     return None;
                 }
 
-            // Echo characters
-            if char.is_ascii_control() {
-                print!("{}\r\n", char as u8);
-            } else {
-                print!("{} ('{}')\r\n", char as u8, char);
-            }
-
-        } else {
                 print!("{:?}\r\n", chars);
-            // Handle escape sequences
-        }
 
+                // Continue the main input loop
                 Some(())
             }
+        }
+    }
 }
 
-const fn CTRL_KEY(c: char) -> char {
-    let key = c as u8;
+// Output
+impl Editor {
+    pub fn refresh_screen() {
+        let stdout = io::stdout();
+        let mut handle = stdout.lock();
 
-    (key & 0x1f) as char
+        let mut buffer = String::from("\x1b[2J").into_bytes();
+
+        handle.write_all(&mut buffer).unwrap();
+    }
 }

src/helpers.rs

@@ -11,21 +11,40 @@ use std::os::unix::io::RawFd;
 use std::process::exit;
 
 // Redefine the posix constants for rust land
+
+/// The value of the raw file descriptor for STDIN
 pub const STDIN_FILENO: i32 = 0;
 // pub const STDOUT_FILENO: i32 = 1;
 // pub const STDERR_FILENO: i32 = 2;
 
+/// Convert Ctrl+letter chords to their
+/// ASCII table equivalents
+#[inline]
+pub fn ctrl_key(c: char) -> char {
+    let key = c as u8;
+
+    if !c.is_ascii() {
+        panic!("CTRL_KEY only accepts ASCII characters");
+    }
+
+    // Intentionally "overflow" u8 to wrap around to the
+    // beginning of the ASCII table. Ctrl+a is 1, Ctrl+b is 2, etc.
+    (key & 0x1f) as char
+}
+
 pub fn die(code: &Errno, msg: &str) -> ! {
     eprintln!("{:?} ({})", code, msg);
 
     exit(1)
 }
 
+/// Get a `Termios` struct, for getting/setting terminal flags
 pub fn get_termios(fd: RawFd) -> Termios {
     termios::tcgetattr(fd).unwrap()
 }
 
-pub fn enable_raw_mode() -> Result<(), Error> {
+/// Put terminal into raw mode so there is full control of terminal output
+pub fn enable_raw_mode() {
     let mut raw = get_termios(STDIN_FILENO);
 
     raw.input_flags.remove(
@@ -59,21 +78,11 @@ pub fn enable_raw_mode() -> Result<(), Error> {
     raw.control_chars[SpecialCharacterIndices::VMIN as usize] = 0;
     raw.control_chars[SpecialCharacterIndices::VTIME as usize] = 1;
 
-    match termios::tcsetattr(STDIN_FILENO, termios::SetArg::TCSAFLUSH, &raw) {
-        Ok(()) => Ok(()),
-        Err(e) => match e.as_errno() {
-            Some(errno) => die(&errno, "tcsetattr"),
-            None => panic!("Failed to enable raw mode"),
-        },
-    }
+    // Raw mode or bust!
+    termios::tcsetattr(STDIN_FILENO, termios::SetArg::TCSAFLUSH, &raw).unwrap();
 }
 
-pub fn disable_raw_mode(original: &Termios) -> Result<(), Error> {
-    match termios::tcsetattr(STDIN_FILENO, termios::SetArg::TCSAFLUSH, original) {
-        Ok(()) => Ok(()),
-        Err(E) => match E.as_errno() {
-            Some(errno) => die(&errno, "tcsetattr"),
-            None => panic!("Failed to disable raw mode"),
-        },
-    }
+/// Restore terminal to "cooked"/canonical mode
+pub fn disable_raw_mode(original: &Termios) {
+    termios::tcsetattr(STDIN_FILENO, termios::SetArg::TCSAFLUSH, original).unwrap();
 }

src/main.rs

@@ -5,15 +5,22 @@ use crate::editor::Editor;
 use crate::helpers::*;
 
 fn main() {
+    // Save original terminal flags
     let original_termios = get_termios(STDIN_FILENO);
 
-    enable_raw_mode().unwrap();
+    // Disable canonical/"cooked" terminal mode
+    enable_raw_mode();
 
+    // Initialize the editor
     let mut editor = Editor::new();
 
+    // Main input loop. Editor::process_keypress uses an Option Enum as a sentinel.
+    // `None` is returned on a quit action, in other cases, `Some(())` is returned,
+    // continuing the loop
     while editor.process_keypress().is_some() {
         // loop
     }
 
-    disable_raw_mode(&original_termios).unwrap();
+    // Restore previous terminal flags before exit
+    disable_raw_mode(&original_termios);
 }