TUIのオーバーホール実装

crates/tui/src/cache.rs

@@ -0,0 +1,52 @@
+//! File content cache for the Edit renderer.
+//!
+//! Holds `path → content` for every file the TUI has observed via a
+//! successful Read (where `ToolResult.output` contains the file body),
+//! Write (where `args.content` is the new body), or Edit (which mutates
+//! the cached body in-place). The cache is purely a display-side view —
+//! it has no opinion on what the filesystem actually contains.
+
+use std::collections::HashMap;
+
+#[derive(Default)]
+pub struct FileCache {
+    contents: HashMap<String, String>,
+}
+
+impl FileCache {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn put(&mut self, path: impl Into<String>, content: impl Into<String>) {
+        self.contents.insert(path.into(), content.into());
+    }
+
+    pub fn get(&self, path: &str) -> Option<&str> {
+        self.contents.get(path).map(String::as_str)
+    }
+
+    /// Apply an Edit-style substitution. When `old` is unique in the
+    /// cached content we swap it for `new`; otherwise we leave the
+    /// cache untouched (the TUI can't reliably reconstruct the new
+    /// state in that case).
+    pub fn apply_edit(&mut self, path: &str, old: &str, new: &str) {
+        let Some(current) = self.contents.get(path) else {
+            return;
+        };
+        // Only swap when `old` appears exactly once — mirrors the
+        // tool's own precondition and keeps the cache from diverging
+        // when ambiguity would otherwise force a guess.
+        let mut occurrences = current.match_indices(old);
+        let first = occurrences.next();
+        let second = occurrences.next();
+        if let (Some((idx, matched)), None) = (first, second) {
+            let end = idx + matched.len();
+            let mut buf = String::with_capacity(current.len() - old.len() + new.len());
+            buf.push_str(&current[..idx]);
+            buf.push_str(new);
+            buf.push_str(&current[end..]);
+            self.contents.insert(path.to_owned(), buf);
+        }
+    }
+}