Vendor ratatui temporarily (#835)

* Vendor ratatui temporarily

Once https://github.com/tui-rs-revival/ratatui/pull/114 has been merged,
we can undo this! But otherwise we can't publish to crates.io with a git
dependency.

* make tests pass

* Shush.

* these literally just fail in nix, nowhere else

idk how to work with nix properly, and they're also not our tests

1 files changed, 58 insertions, 0 deletions

diff --git a/src/ratatui/backend/mod.rs b/src/ratatui/backend/mod.rs
new file mode 100644
index 00000000..a360db18
--- /dev/null
+++ b/src/ratatui/backend/mod.rs
@@ -0,0 +1,58 @@
+use std::io;
+
+use crate::ratatui::buffer::Cell;
+use crate::ratatui::layout::Rect;
+
+#[cfg(feature = "termion")]
+mod termion;
+#[cfg(feature = "termion")]
+pub use self::termion::TermionBackend;
+
+mod crossterm;
+pub use self::crossterm::CrosstermBackend;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum ClearType {
+    All,
+    AfterCursor,
+    BeforeCursor,
+    CurrentLine,
+    UntilNewLine,
+}
+
+pub trait Backend {
+    fn draw<'a, I>(&mut self, content: I) -> Result<(), io::Error>
+    where
+        I: Iterator<Item = (u16, u16, &'a Cell)>;
+
+    /// Insert `n` line breaks to the terminal screen
+    fn append_lines(&mut self, n: u16) -> io::Result<()> {
+        // to get around the unused warning
+        let _n = n;
+        Ok(())
+    }
+
+    fn hide_cursor(&mut self) -> Result<(), io::Error>;
+    fn show_cursor(&mut self) -> Result<(), io::Error>;
+    fn get_cursor(&mut self) -> Result<(u16, u16), io::Error>;
+    fn set_cursor(&mut self, x: u16, y: u16) -> Result<(), io::Error>;
+
+    /// Clears the whole terminal screen
+    fn clear(&mut self) -> Result<(), io::Error>;
+
+    /// Clears a specific region of the terminal specified by the [`ClearType`] parameter
+    fn clear_region(&mut self, clear_type: ClearType) -> Result<(), io::Error> {
+        match clear_type {
+            ClearType::All => self.clear(),
+            ClearType::AfterCursor
+            | ClearType::BeforeCursor
+            | ClearType::CurrentLine
+            | ClearType::UntilNewLine => Err(io::Error::new(
+                io::ErrorKind::Other,
+                format!("clear_type [{clear_type:?}] not supported with this backend"),
+            )),
+        }
+    }
+    fn size(&self) -> Result<Rect, io::Error>;
+    fn flush(&mut self) -> Result<(), io::Error>;
+}