From d0d17d259462d3b54bf0b1f560d7324f92997ade Mon Sep 17 00:00:00 2001
From: Tatsuyuki Ishi <ishitatsuyuki@gmail.com>
Date: Thu, 16 Dec 2021 15:00:54 +0900
Subject: [PATCH] Implement ProgressBar::suspend

---
 src/progress_bar.rs | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/src/progress_bar.rs b/src/progress_bar.rs
index 062b5939..8cd2f22b 100644
--- a/src/progress_bar.rs
+++ b/src/progress_bar.rs
@@ -231,11 +231,12 @@ impl ProgressBar {
 
     /// Print a log line above the progress bar
     ///
+    /// If the progress bar is hidden (e.g. when standard output is not a terminal), `println()`
+    /// will not do anything. If you want to write to the standard output in such cases as well, use
+    /// \[`suspend`\] instead.
+    ///
     /// If the progress bar was added to a [`MultiProgress`], the log line will be
     /// printed above all other progress bars.
-    ///
-    /// Note that if the progress bar is hidden (which by default happens if the progress bar is
-    /// redirected into a file) `println()` will not do anything either.
     pub fn println<I: AsRef<str>>(&self, msg: I) {
         let mut state = self.state.lock().unwrap();
 
@@ -406,6 +407,29 @@ impl ProgressBar {
         state.draw_target = target;
     }
 
+    /// Hide the progress bar temporarily, execute `f`, then redraw the progress bar.
+    /// Useful for external code that writes to the standard output.
+    ///
+    /// **Note:** The internal lock is held while `f` is executed. Other threads trying to print
+    /// anything on the progress bar will be blocked until `f` finishes.
+    /// Therefore, it is recommended to not do long-running operations in `f`.
+    ///
+    /// ```rust,no_run
+    /// # use indicatif::ProgressBar;
+    /// let mut pb = ProgressBar::new(3);
+    /// pb.suspend(|| {
+    ///     println!("Log message");
+    /// })
+    /// ```
+    pub fn suspend<F: FnOnce()>(&mut self, f: F) {
+        let mut state = self.state.lock().unwrap();
+        let _ = state
+            .draw_target
+            .apply_draw_state(ProgressDrawState::new(vec![], true));
+        f();
+        let _ = state.draw(true);
+    }
+
     /// Wraps an [`Iterator`] with the progress bar
     ///
     /// ```rust,no_run