Extract rollout into its own crate (#15548)

codex-rs/rollout/src/session_index.rs

@@ -0,0 +1,233 @@
+use std::collections::HashMap;
+use std::collections::HashSet;
+use std::fs::File;
+use std::io::Read;
+use std::io::Seek;
+use std::io::SeekFrom;
+use std::path::Path;
+use std::path::PathBuf;
+
+use codex_protocol::ThreadId;
+use serde::Deserialize;
+use serde::Serialize;
+use tokio::io::AsyncBufReadExt;
+use tokio::io::AsyncWriteExt;
+
+const SESSION_INDEX_FILE: &str = "session_index.jsonl";
+const READ_CHUNK_SIZE: usize = 8192;
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+pub struct SessionIndexEntry {
+    pub id: ThreadId,
+    pub thread_name: String,
+    pub updated_at: String,
+}
+
+/// Append a thread name update to the session index.
+/// The index is append-only; the most recent entry wins when resolving names or ids.
+pub async fn append_thread_name(
+    codex_home: &Path,
+    thread_id: ThreadId,
+    name: &str,
+) -> std::io::Result<()> {
+    use time::OffsetDateTime;
+    use time::format_description::well_known::Rfc3339;
+
+    let updated_at = OffsetDateTime::now_utc()
+        .format(&Rfc3339)
+        .unwrap_or_else(|_| "unknown".to_string());
+    let entry = SessionIndexEntry {
+        id: thread_id,
+        thread_name: name.to_string(),
+        updated_at,
+    };
+    append_session_index_entry(codex_home, &entry).await
+}
+
+/// Append a raw session index entry to `session_index.jsonl`.
+/// The file is append-only; consumers scan from the end to find the newest match.
+pub async fn append_session_index_entry(
+    codex_home: &Path,
+    entry: &SessionIndexEntry,
+) -> std::io::Result<()> {
+    let path = session_index_path(codex_home);
+    let mut file = tokio::fs::OpenOptions::new()
+        .create(true)
+        .append(true)
+        .open(&path)
+        .await?;
+    let mut line = serde_json::to_string(entry).map_err(std::io::Error::other)?;
+    line.push('\n');
+    file.write_all(line.as_bytes()).await?;
+    file.flush().await?;
+    Ok(())
+}
+
+/// Find the latest thread name for a thread id, if any.
+pub async fn find_thread_name_by_id(
+    codex_home: &Path,
+    thread_id: &ThreadId,
+) -> std::io::Result<Option<String>> {
+    let path = session_index_path(codex_home);
+    if !path.exists() {
+        return Ok(None);
+    }
+    let id = *thread_id;
+    let entry = tokio::task::spawn_blocking(move || scan_index_from_end_by_id(&path, &id))
+        .await
+        .map_err(std::io::Error::other)??;
+    Ok(entry.map(|entry| entry.thread_name))
+}
+
+/// Find the latest thread names for a batch of thread ids.
+pub async fn find_thread_names_by_ids(
+    codex_home: &Path,
+    thread_ids: &HashSet<ThreadId>,
+) -> std::io::Result<HashMap<ThreadId, String>> {
+    let path = session_index_path(codex_home);
+    if thread_ids.is_empty() || !path.exists() {
+        return Ok(HashMap::new());
+    }
+
+    let file = tokio::fs::File::open(&path).await?;
+    let reader = tokio::io::BufReader::new(file);
+    let mut lines = reader.lines();
+    let mut names = HashMap::with_capacity(thread_ids.len());
+
+    while let Some(line) = lines.next_line().await? {
+        let trimmed = line.trim();
+        if trimmed.is_empty() {
+            continue;
+        }
+        let Ok(entry) = serde_json::from_str::<SessionIndexEntry>(trimmed) else {
+            continue;
+        };
+        let name = entry.thread_name.trim();
+        if !name.is_empty() && thread_ids.contains(&entry.id) {
+            names.insert(entry.id, name.to_string());
+        }
+    }
+
+    Ok(names)
+}
+
+/// Find the most recently updated thread id for a thread name, if any.
+pub async fn find_thread_id_by_name(
+    codex_home: &Path,
+    name: &str,
+) -> std::io::Result<Option<ThreadId>> {
+    if name.trim().is_empty() {
+        return Ok(None);
+    }
+    let path = session_index_path(codex_home);
+    if !path.exists() {
+        return Ok(None);
+    }
+    let name = name.to_string();
+    let entry = tokio::task::spawn_blocking(move || scan_index_from_end_by_name(&path, &name))
+        .await
+        .map_err(std::io::Error::other)??;
+    Ok(entry.map(|entry| entry.id))
+}
+
+/// Locate a recorded thread rollout file by thread name using newest-first ordering.
+/// Returns `Ok(Some(path))` if found, `Ok(None)` if not present.
+pub async fn find_thread_path_by_name_str(
+    codex_home: &Path,
+    name: &str,
+) -> std::io::Result<Option<PathBuf>> {
+    let Some(thread_id) = find_thread_id_by_name(codex_home, name).await? else {
+        return Ok(None);
+    };
+    super::list::find_thread_path_by_id_str(codex_home, &thread_id.to_string()).await
+}
+
+fn session_index_path(codex_home: &Path) -> PathBuf {
+    codex_home.join(SESSION_INDEX_FILE)
+}
+
+fn scan_index_from_end_by_id(
+    path: &Path,
+    thread_id: &ThreadId,
+) -> std::io::Result<Option<SessionIndexEntry>> {
+    scan_index_from_end(path, |entry| entry.id == *thread_id)
+}
+
+fn scan_index_from_end_by_name(
+    path: &Path,
+    name: &str,
+) -> std::io::Result<Option<SessionIndexEntry>> {
+    scan_index_from_end(path, |entry| entry.thread_name == name)
+}
+
+fn scan_index_from_end<F>(
+    path: &Path,
+    mut predicate: F,
+) -> std::io::Result<Option<SessionIndexEntry>>
+where
+    F: FnMut(&SessionIndexEntry) -> bool,
+{
+    let mut file = File::open(path)?;
+    let mut remaining = file.metadata()?.len();
+    let mut line_rev: Vec<u8> = Vec::new();
+    let mut buf = vec![0u8; READ_CHUNK_SIZE];
+
+    while remaining > 0 {
+        let read_size = usize::try_from(remaining.min(READ_CHUNK_SIZE as u64))
+            .map_err(std::io::Error::other)?;
+        remaining -= read_size as u64;
+        file.seek(SeekFrom::Start(remaining))?;
+        file.read_exact(&mut buf[..read_size])?;
+
+        for &byte in buf[..read_size].iter().rev() {
+            if byte == b'\n' {
+                if let Some(entry) = parse_line_from_rev(&mut line_rev, &mut predicate)? {
+                    return Ok(Some(entry));
+                }
+                continue;
+            }
+            line_rev.push(byte);
+        }
+    }
+
+    if let Some(entry) = parse_line_from_rev(&mut line_rev, &mut predicate)? {
+        return Ok(Some(entry));
+    }
+
+    Ok(None)
+}
+
+fn parse_line_from_rev<F>(
+    line_rev: &mut Vec<u8>,
+    predicate: &mut F,
+) -> std::io::Result<Option<SessionIndexEntry>>
+where
+    F: FnMut(&SessionIndexEntry) -> bool,
+{
+    if line_rev.is_empty() {
+        return Ok(None);
+    }
+    line_rev.reverse();
+    let line = std::mem::take(line_rev);
+    let Ok(mut line) = String::from_utf8(line) else {
+        return Ok(None);
+    };
+    if line.ends_with('\r') {
+        line.pop();
+    }
+    let trimmed = line.trim();
+    if trimmed.is_empty() {
+        return Ok(None);
+    }
+    let Ok(entry) = serde_json::from_str::<SessionIndexEntry>(trimmed) else {
+        return Ok(None);
+    };
+    if predicate(&entry) {
+        return Ok(Some(entry));
+    }
+    Ok(None)
+}
+
+#[cfg(test)]
+#[path = "session_index_tests.rs"]
+mod tests;