Replace LineIndex::from_reader(BufReader) with LineIndex::from_bytes(&mmap)
in both open() and reload(), ensuring the line index is always built from
the same mmap snapshot rather than a separate read through the file descriptor.
This closes the race window where an external file modification between
mmap() and from_reader() could cause line_index offsets to disagree with
the mmap data, leading to get_line() returning wrong content or panicking.
Closes#2
File truncation/rotation during mmap lifetime caused SIGBUS crash
because update_for_append() ignored new_size < old_size, leaving
a stale mapping that would fault on access.
Introduce AppendStatus enum (Unchanged/Appended/Reloaded) so the
caller can distinguish shrink events from normal appends. On shrink,
reload() rebuilds the mmap and line index. The TUI layer clamps
cursor and invalidates viewport cache on Reloaded, matching the
existing handle_file_truncated() behavior.
Fixes#1
Add SCAN_AHEAD_LIMIT (10000 lines) to get_line() in Sampling state. Without this, jumping to end-of-file (G) during progressive loading would scan the entire file byte-by-byte on the main thread, blocking the UI and consuming excessive memory. Lines beyond the scanned region + limit now return None, which the TUI renders as empty.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Add ProgressiveFileReader state machine (Sampling/Ready/Error) with scanned_newlines cache for O(1) line lookups. Implement spawn_indexer() for background mmap-based indexing with cancellation and progress reporting. Add VisualHeightIndex with prefix-sum + binary search for O(log N) visual height queries. Register all new io submodules and extend FileReader with reload(), save_cache(), and accessor methods.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Move wrap_line_chars and format_json_line from app.rs to core/io/wrap.rs with MAX_WRAP_INPUT_LEN guard. Add serde derives, pub getters, and extend_from_bytes() to LineIndex for incremental index building.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Implement head/tail 64KB sampling to estimate total line count without scanning the entire file. Also provide read_first_lines() for reading the first N lines for immediate display during progressive loading.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Add xxhash-rust and bincode workspace dependencies for fast hashing and serialization. Implement cache_util for cache directory/path resolution with versioning, and IndexCache for saving/loading line indices to disk with file-hash validation.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Replace Vec<u8> with memmap2::Mmap for file content. Build line index via BufReader streaming (from_reader) instead of scanning mmap'd data, keeping RSS at ~3MB for 5GB files instead of ~5GB.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Rewrite LineIndex to use sparse sampling (every 256 lines) instead of per-line offsets. Add from_reader() for low-RSS streaming index construction via BufReader fill_buf()/consume(), reducing 5GB file RSS from 5122MB to 3.4MB.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
dailz