Add start and with_task to ProgressBar

examples/progress.rs

@@ -4,8 +4,6 @@ use cursive::prelude::*;
 
 use std::thread;
 use std::time::Duration;
-use std::sync::Arc;
-use std::sync::atomic::{AtomicUsize, Ordering};
 
 fn main() {
     let mut siv = Cursive::new();
@@ -14,37 +12,36 @@ fn main() {
         .title("Progress bar example")
         .padding((0, 0, 1, 1))
         .content(Button::new("Start", |s| {
-            // These two values will allow us to communicate.
+            // Number of ticks
-            let value = Arc::new(AtomicUsize::new(0));
-
             let n_max = 1000;
 
-            s.pop_layer();
+            // This is the callback channel
-            s.add_layer(Panel::new(FullView::full_width(ProgressBar::new()
-                    .range(0, n_max)
-                    .with_value(value.clone()))));
-
             let cb = s.cb_sink().clone();
 
-            // Spawn a thread to process things in the background.
+            s.pop_layer();
-            thread::spawn(move || {
+            s.add_layer(Panel::new(FullView::full_width(
+                ProgressBar::new()
+                    .range(0, n_max)
+                    .with_task(move |ticker| {
+                        // This closure will be called in a separate thread.
                         for _ in 0..n_max {
-                    thread::sleep(Duration::from_millis(20));
+                            thread::sleep(Duration::from_millis(5));
-                    value.fetch_add(1, Ordering::Relaxed);
+                            // The ticker method increases the progress value
+                            ticker(1);
                         }
+
+                        // When we're done, send a callback through the channel
                         cb.send(Box::new(move |s| {
                             s.pop_layer();
                             s.add_layer(Dialog::empty()
                                         .title("Work done!")
-                            .content(TextView::new("Phew, that was some \
+                                        .content(TextView::new("Phew!"))
-                                                    work!"))
+                                        .button("Finally!", |s| s.quit()));
-                            .button("Sure!", |s| s.quit()));
                         }))
                         .unwrap();
-            });
+                    })
-
+            )));
-        }))
+        })));
-        .with_id("dialog"));
 
     siv.set_fps(30);
 

src/view/progress_bar.rs

@@ -1,5 +1,6 @@
 use std::sync::Arc;
 
+use std::thread;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
 use {Cursive, Printer};
@@ -18,6 +19,8 @@ pub struct ProgressBar {
     label_maker: Box<Fn(usize, (usize, usize)) -> String>,
 }
 
+pub type Ticker = Box<Fn(usize) + Send>;
+
 fn make_percentage(value: usize, (min, max): (usize, usize)) -> String {
     let percent = 101 * (value - min) / (1 + max - min);
     format!("{} %", percent)
@@ -43,11 +46,36 @@ impl ProgressBar {
     }
 
     /// Sets the value to follow.
+    ///
+    /// Use this to manually control the progress to display
+    /// by directly modifying the value pointed to by `value`.
     pub fn with_value(mut self, value: Arc<AtomicUsize>) -> Self {
         self.value = value;
         self
     }
 
+    /// Starts a function in a separate thread, and monitor the progress.
+    ///
+    /// `f` will be given a `Ticker` to increment the bar's progress.
+    pub fn start<F: FnOnce(Ticker) + Send + 'static>(&mut self, f: F) {
+        let value = self.value.clone();
+        let ticker: Ticker = Box::new(move |ticks| {
+            value.fetch_add(ticks, Ordering::Relaxed);
+        });
+
+        thread::spawn(move || {
+            f(ticker);
+        });
+    }
+
+    /// Starts a function in a separate thread, and monitor the progress.
+    ///
+    /// Chainable variant.
+    pub fn with_task<F: FnOnce(Ticker) + Send + 'static>(mut self, task: F) -> Self {
+        self.start(task);
+        self
+    }
+
     /// Sets the label generator.
     ///
     /// The given function will be called with `(value, (min, max))`.