1 files changed, 130 insertions, 0 deletions

diff --git a/crates/ra_cli/src/progress_bar.rs b/crates/ra_cli/src/progress_bar.rs
new file mode 100644
index 000000000..95bfcf4d0
--- /dev/null
+++ b/crates/ra_cli/src/progress_bar.rs
@@ -0,0 +1,130 @@
+//! A simple progress bar
+//!
+//! A single thread non-optimized progress bar
+use std::io::Write;
+
+/// A Simple ASCII Progress Bar
+pub struct ProgressBar {
+    curr: f32,
+    text: String,
+    anim: usize,
+    hidden: bool,
+
+    len: u64,
+    pos: u64,
+    msg: String,
+}
+
+impl ProgressBar {
+    const ANIMATION: &'static str = r#"|/-\"#;
+    const BLOCK_COUNT: usize = 20;
+
+    pub fn new(len: u64) -> ProgressBar {
+        ProgressBar {
+            curr: 0.0,
+            text: String::new(),
+            anim: 0,
+            hidden: false,
+            len,
+            pos: 0,
+            msg: String::new(),
+        }
+    }
+
+    pub fn hidden() -> ProgressBar {
+        ProgressBar {
+            curr: 0.0,
+            text: String::new(),
+            anim: 0,
+            hidden: true,
+            len: 0,
+            pos: 0,
+            msg: String::new(),
+        }
+    }
+
+    pub fn set_message(&mut self, msg: &str) {
+        self.msg = msg.to_string();
+        self.tick();
+    }
+
+    pub fn println<I: Into<String>>(&mut self, msg: I) {
+        self.clear();
+        println!("{}", msg.into());
+        self.tick();
+    }
+
+    pub fn inc(&mut self, delta: u64) {
+        self.pos += delta;
+        if self.len == 0 {
+            self.set_value(0.0)
+        } else {
+            self.set_value((self.pos as f32) / (self.len as f32))
+        }
+        self.tick();
+    }
+
+    pub fn finish_and_clear(&mut self) {
+        self.clear();
+    }
+
+    pub fn tick(&mut self) {
+        if self.hidden {
+            return;
+        }
+
+        let progress_block: usize = (self.curr * Self::BLOCK_COUNT as f32) as usize;
+        let percent = (self.curr * 100.0) as u32;
+        let text = format!(
+            "[{}{}] {:3>}% {} {}",
+            "#".repeat(progress_block),
+            "-".repeat(Self::BLOCK_COUNT - progress_block),
+            percent,
+            Self::ANIMATION.chars().nth(self.anim).unwrap(),
+            self.msg,
+        );
+
+        self.anim = (self.anim + 1) % Self::ANIMATION.len();
+        self.update_text(&text);
+    }
+
+    fn update_text(&mut self, text: &str) {
+        // Get length of common portion
+        let mut common_prefix_length = 0;
+        let common_length = usize::min(self.text.len(), text.len());
+
+        while common_prefix_length < common_length
+            && text.chars().nth(common_prefix_length).unwrap()
+                == self.text.chars().nth(common_prefix_length).unwrap()
+        {
+            common_prefix_length += 1;
+        }
+
+        // Backtrack to the first differing character
+        let mut output = String::new();
+        output += &'\x08'.to_string().repeat(self.text.len() - common_prefix_length);
+        // Output new suffix
+        output += &text[common_prefix_length..text.len()];
+
+        // If the new text is shorter than the old one: delete overlapping characters
+        if let Some(overlap_count) = self.text.len().checked_sub(text.len()) {
+            if overlap_count > 0 {
+                output += &" ".repeat(overlap_count);
+                output += &"\x08".repeat(overlap_count);
+            }
+        }
+
+        let _ = std::io::stdout().write(output.as_bytes());
+        let _ = std::io::stdout().flush();
+        self.text = text.to_string();
+    }
+
+    fn set_value(&mut self, value: f32) {
+        self.curr = f32::max(0.0, f32::min(1.0, value));
+    }
+
+    fn clear(&mut self) {
+        print!("{}", "\x08".repeat(self.text.len()));
+        self.text = String::new();
+    }
+}