Fix some compiler warnings

Also enables debug symbols in release profile by default. Until
Alacritty ships, there's going to be lots of perf analysis which needs
debug symbols.

The PriorityMutex low priority method was never used. Now it's just a
fair mutex.

5 files changed, 25 insertions, 80 deletions

diff --git a/src/ansi.rs b/src/ansi.rs
index 8a4a36af..48f79d2b 100644
--- a/src/ansi.rs
+++ b/src/ansi.rs
@@ -52,7 +52,7 @@ struct ProcessorState;
 /// Processor creates a Performer when running advance and passes the Performer
 /// to vte::Parser.
 struct Performer<'a, H: Handler + TermInfo + 'a> {
-    state: &'a mut ProcessorState,
+    _state: &'a mut ProcessorState,
     handler: &'a mut H
 }
 
@@ -61,7 +61,7 @@ impl<'a, H: Handler + TermInfo + 'a> Performer<'a, H> {
     #[inline]
     pub fn new<'b>(state: &'b mut ProcessorState, handler: &'b mut H) -> Performer<'b, H> {
         Performer {
-            state: state,
+            _state: state,
             handler: handler
         }
     }
@@ -648,9 +648,7 @@ impl<'a, H: Handler + TermInfo + 'a> vte::Perform for Performer<'a, H> {
     }
 
     #[inline]
-    fn esc_dispatch(&mut self, params: &[i64], intermediates: &[u8], ignore: bool, byte: u8) {
-        let private = intermediates.get(0).map(|b| *b == b'?').unwrap_or(false);
-
+    fn esc_dispatch(&mut self, params: &[i64], intermediates: &[u8], _ignore: bool, byte: u8) {
         match byte {
             b'D' => self.handler.linefeed(),
             b'E' => self.handler.newline(),
diff --git a/src/event.rs b/src/event.rs
index bb5eebe0..303c6d8e 100644
--- a/src/event.rs
+++ b/src/event.rs
@@ -5,15 +5,14 @@ use std;
 use glutin;
 
 use input;
-use sync::PriorityMutex;
+use sync::FairMutex;
 use term::Term;
-use tty::process_should_exit;
 
 /// The event processor
 pub struct Processor<'a, W: 'a> {
     writer: &'a mut W,
     input_processor: input::Processor,
-    terminal: Arc<PriorityMutex<Term>>,
+    terminal: Arc<FairMutex<Term>>,
     resize_tx: mpsc::Sender<(u32, u32)>,
 }
 
@@ -25,7 +24,7 @@ impl<'a, W> Processor<'a, W>
     /// Takes a writer which is expected to be hooked up to the write end of a
     /// pty.
     pub fn new(writer: &mut W,
-               terminal: Arc<PriorityMutex<Term>>,
+               terminal: Arc<FairMutex<Term>>,
                resize_tx: mpsc::Sender<(u32, u32)>)
                -> Processor<W>
     {
@@ -55,12 +54,12 @@ impl<'a, W> Processor<'a, W>
             glutin::Event::Resized(w, h) => {
                 self.resize_tx.send((w, h)).expect("send new size");
                 // Acquire term lock
-                let mut terminal = self.terminal.lock_high();
+                let mut terminal = self.terminal.lock();
                 terminal.dirty = true;
             },
             glutin::Event::KeyboardInput(state, _code, key, mods) => {
                 // Acquire term lock
-                let terminal = self.terminal.lock_high();
+                let terminal = self.terminal.lock();
 
                 self.input_processor.process(state, key, mods,
                                              &mut input::WriteNotifier(self.writer),
diff --git a/src/main.rs b/src/main.rs
index 0b72c374..e520b08d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -56,12 +56,12 @@ mod sync;
 use std::sync::{mpsc, Arc};
 use std::sync::atomic::{AtomicBool, Ordering};
 
-use parking_lot::{Condvar, Mutex, MutexGuard};
+use parking_lot::{MutexGuard};
 
 use config::Config;
 use meter::Meter;
 use renderer::{QuadRenderer, GlyphCache};
-use sync::PriorityMutex;
+use sync::FairMutex;
 use term::Term;
 use tty::process_should_exit;
 use util::thread;
@@ -183,7 +183,7 @@ fn main() {
 
     let signal_flag = Flag::new(false);
 
-    let terminal = Arc::new(PriorityMutex::new(terminal));
+    let terminal = Arc::new(FairMutex::new(terminal));
     let window = Arc::new(window);
 
     let pty_reader = PtyReader::spawn(
@@ -196,7 +196,6 @@ fn main() {
     // Wraps a renderer and gives simple draw() api.
     let mut display = Display::new(
         window.clone(),
-        terminal.clone(),
         renderer,
         glyph_cache,
         render_timer,
@@ -212,7 +211,7 @@ fn main() {
         processor.process_events(&window);
 
         // Maybe draw the terminal
-        let terminal = terminal.lock_high();
+        let terminal = terminal.lock();
         signal_flag.set(false);
         if terminal.dirty {
             display.draw(terminal);
@@ -231,7 +230,7 @@ fn main() {
 struct PtyReader;
 
 impl PtyReader {
-    pub fn spawn<R>(terminal: Arc<PriorityMutex<Term>>,
+    pub fn spawn<R>(terminal: Arc<FairMutex<Term>>,
                     mut pty: R,
                     proxy: ::glutin::WindowProxy,
                     signal_flag: Flag)
@@ -244,7 +243,7 @@ impl PtyReader {
 
             loop {
                 if let Ok(got) = pty.read(&mut buf[..]) {
-                    let mut terminal = terminal.lock_high();
+                    let mut terminal = terminal.lock();
 
                     for byte in &buf[..got] {
                         pty_parser.advance(&mut *terminal, *byte);
@@ -271,7 +270,6 @@ impl PtyReader {
 
 struct Display {
     window: Arc<glutin::Window>,
-    terminal_mutex: Arc<PriorityMutex<Term>>,
     renderer: QuadRenderer,
     glyph_cache: GlyphCache,
     render_timer: bool,
@@ -281,7 +279,6 @@ struct Display {
 
 impl Display {
     pub fn new(window: Arc<glutin::Window>,
-               terminal_mutex: Arc<PriorityMutex<Term>>,
                renderer: QuadRenderer,
                glyph_cache: GlyphCache,
                render_timer: bool,
@@ -290,7 +287,6 @@ impl Display {
     {
         Display {
             window: window,
-            terminal_mutex: terminal_mutex,
             renderer: renderer,
             glyph_cache: glyph_cache,
             render_timer: render_timer,
diff --git a/src/sync.rs b/src/sync.rs
index e341d78e..e314b7e8 100644
--- a/src/sync.rs
+++ b/src/sync.rs
@@ -14,81 +14,34 @@
 
 //! Synchronization types
 //!
-//! Most importantly, a priority mutex is included
-use std::ops::{Deref, DerefMut};
-
+//! Most importantly, a fair mutex is included
 use parking_lot::{Mutex, MutexGuard};
 
-/// A priority mutex
-///
-/// A triple locking strategy is used where low priority locks must go through an additional mutex
-/// to access the data. The gist is
-///
-/// Low priority: lock low, lock next, lock data, unlock next, {do work}, unlock data, unlock low
-/// High priority: lock next, lock data, unlock next, {do work}, unlock data
+/// A fair mutex
 ///
-/// By keeping the low lock active while working on data, a high priority consumer has immediate
-/// access to the next mutex.
-pub struct PriorityMutex<T> {
+/// Uses an extra lock to ensure that if one thread is waiting that it will get
+/// the lock before a single thread can re-lock it.
+pub struct FairMutex<T> {
     /// Data
     data: Mutex<T>,
     /// Next-to-access
     next: Mutex<()>,
-    /// Low-priority access
-    low: Mutex<()>,
-}
-
-/// Mutex guard for low priority locks
-pub struct LowPriorityMutexGuard<'a, T: 'a> {
-    data: MutexGuard<'a, T>,
-    _low: MutexGuard<'a, ()>,
 }
 
-impl<'a, T> Deref for LowPriorityMutexGuard<'a, T> {
-    type Target = T;
-
-    #[inline]
-    fn deref(&self) -> &T {
-        self.data.deref()
-    }
-}
-
-impl<'a, T> DerefMut for LowPriorityMutexGuard<'a, T> {
-    #[inline]
-    fn deref_mut(&mut self) -> &mut T {
-        self.data.deref_mut()
-    }
-}
-
-impl<T> PriorityMutex<T> {
-    /// Create a new priority mutex
-    pub fn new(data: T) -> PriorityMutex<T> {
-        PriorityMutex {
+impl<T> FairMutex<T> {
+    /// Create a new fair mutex
+    pub fn new(data: T) -> FairMutex<T> {
+        FairMutex {
             data: Mutex::new(data),
             next: Mutex::new(()),
-            low: Mutex::new(()),
         }
     }
 
-    /// Lock the mutex with high priority
-    pub fn lock_high(&self) -> MutexGuard<T> {
+    /// Lock the mutex
+    pub fn lock(&self) -> MutexGuard<T> {
         // Must bind to a temporary or the lock will be freed before going
         // into data.lock()
         let _next = self.next.lock();
         self.data.lock()
     }
-
-    /// Lock the mutex with low priority
-    pub fn lock_low(&self) -> LowPriorityMutexGuard<T> {
-        let low = self.low.lock();
-        // Must bind to a temporary or the lock will be freed before going
-        // into data.lock()
-        let _next = self.next.lock();
-        let data = self.data.lock();
-
-        LowPriorityMutexGuard {
-            data: data,
-            _low: low,
-        }
-    }
 }
diff --git a/src/term.rs b/src/term.rs
index 58f60b87..c209d4ad 100644
--- a/src/term.rs
+++ b/src/term.rs
@@ -456,7 +456,6 @@ impl ansi::Handler for Term {
     /// A character to be displayed
     #[inline]
     fn input(&mut self, c: char) {
-        debug_print!("{}; attrs = {:?}", c, self.attr);
         if self.cursor.col == self.grid.num_cols() {
             debug_println!("wrapping");
             if (self.cursor.line + 1) >= self.scroll_region.end {