add basic search

src/document.rs

@@ -94,4 +94,12 @@ impl Document {
     pub fn is_dirty(&self) -> bool {
         self.dirty
     }
+    pub fn find(&self, query: &str) -> Option<Position> {
+        for (y, row) in self.rows.iter().enumerate() {
+            if let Some(x) = row.find(query) {
+                return Some(Position {x, y});
+            }
+        }
+        None
+    }
 }

src/editor.rs

@@ -60,7 +60,7 @@ impl Editor {
     }
     pub fn default() -> Self {
         let args: Vec<String> = env::args().collect();
-        let mut initial_status = String::from("HELP: Ctrl-S = save | Ctrl-Q = quit");
+        let mut initial_status = String::from("HELP: Ctrl-F = find | Ctrl-S = save | Ctrl-Q = quit");
         let document = if let Some(file_name) = args.get(1) {
             let doc = Document::open(file_name);
             if let Ok(doc) = doc {
@@ -106,6 +106,15 @@ impl Editor {
         let pressed_key = Terminal::read_key()?;
         match pressed_key {
             Key::Ctrl('s') => self.save(),
+            Key::Ctrl('f') => {
+                if let Some(query) = self.prompt("Search: ").unwrap_or(None) {
+                    if let Some(position) = self.document.find(&query[..]) {
+                        self.cursor_position = position;
+                    } else {
+                        self.status_message = StatusMessage::from(format!("Not found: {}.", query));
+                    }
+                }
+            }
             Key::Ctrl('q') => {
                 if self.quit_times > 0 && self.document.is_dirty() {
                     self.status_message = StatusMessage::from(format!(

src/row.rs

@@ -1,4 +1,4 @@
-use std::cmp;
+use std::{cmp, usize};
 use unicode_segmentation::UnicodeSegmentation;
 
 #[derive(Default)]
@@ -98,4 +98,15 @@ impl Row {
     pub fn as_bytes(&self) -> &[u8] {
         self.string.as_bytes()
     }
+    pub fn find(&self, query: &str) -> Option<usize> {
+        let matching_byte_index = self.string.find(query);
+        if let Some(matching_byte_index) = matching_byte_index {
+            for (grapheme_index, (byte_index, _)) in self.string[..].grapheme_indices(true).enumerate() {
+                if matching_byte_index == byte_index {
+                    return Some(grapheme_index);
+                }
+            }
+        }
+        None
+    }
 }