HighlighterEngine::GetLine copied the span vector on every call (twice
on a miss) and did a dynamic_cast per call; it now returns the cached
entry (valid until the next call) and dispatches on Stateful().
PieceTable and HighlighterEngine took a mutex in their read paths while
their writes took none, and PieceTable.h claimed concurrent reads were
safe; they are not (reads update caches). Every Buffer is used from the
main thread only (the swap writer thread receives copies; the regex
large-stack thread runs while its caller waits), so the mutexes are
removed and the headers say so. ASan and the threaded tests under TSan
are clean.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
Each edit shifted every later line start in the line index, O(lines) per
keystroke (0.5 ms near the top of a 1M-line file). The shift is now kept
pending ("from entry k, add d") and applied on read; further edits at the
same line only adjust it, and it is folded in when an edit lands
elsewhere.
locate() walked the piece list for every lookup (two per rendered line
per frame on an edited buffer); it now binary-searches prefix sums
rebuilt once per modification (keyed on version_, which every mutation
bumps; AdoptOriginal now bumps it after installing its piece).
Typing on line 10 of a 1M-line file with a frame's worth of line reads
per keystroke: 0.52 ms -> 0.017 ms. A new randomized test checks every
read path against a string model with consolidation forced; it fails
under each of three deliberate breakages of the new bookkeeping.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
A loaded file's bytes are adopted as the piece table's original storage
instead of being appended to the add buffer: the first keystroke no
longer reallocates and copies the whole file (140 ms at 200 MB), and the
read buffer is not copied again.
Save writes the pieces in order instead of materializing the buffer (a
second full copy that then stayed resident). Buffer::Bytes() assembles a
copy from the pieces and replaces four hand-rolled copies (swap
snapshots, recovery comparison, Command.cc's per-row join, the tests'
accessor). A single-piece table (an unedited file) is viewed in place;
GetLineView serves a line from its piece when it lies within one, so it
no longer copies the whole buffer after every edit. Code that needed the
whole text contiguous says so with ContentView().
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
GetLine and LineColToByteOffset fetched each line's last byte (a piece
lookup, an allocation and a cache write) to see whether it was a newline;
the line index already says so: every line but the last ends at one.
LineColToByteOffset runs on every insert. RebuildLineIndex scans with
memchr instead of byte by byte.
Removed, having no callers: OptimizedSearch (built only into its own
test), UndoNodePool.h, SwapManager::RecordSplit/RecordJoin (replay still
reads SPLIT/JOIN), PieceTable::Reserve/Capacity and its capacity
constructor, Buffer's write-only render column, Editor's mode, no-kill,
dirtyex and repeatable flags and the UCount getter, and
RetryPolicy::Conservative.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
- Undo texts of 4 KiB or more (Insert/Paste from the buffer, Delete from
the spans the piece table remembers for its last large deletion) are
held as TextSpan references into the piece table's append-only
storage, after checking they hold exactly the recorded bytes. Undo and
redo insert them with Buffer::insert_spans, which adds pieces over the
stored bytes instead of copying them into storage again (the journal
still gets the bytes, as one record). A replace-all session on a 26 MB
file peaks at 181 MB instead of 332 MB; undo/redo cycles of a 6.6 MB
kill no longer grow memory by 6.6 MB each.
- UndoSystem keeps a byte budget (default max(64 MiB, twice the buffer
size); SetByteBudget). Over it, history is pruned to 75% of the budget:
branches off the current path, then the oldest edits (an undo group
goes whole, and never the current state's group), then the redo line.
When the saved state is dropped the buffer stays modified until saved.
- replace_all_bytes clears undo history, which was recorded against (and
may reference the storage of) the previous content.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
Consolidation rewrites pieces without changing content or offsets but
invalidated the line index, so once a buffer passed the piece limit
every edit paid a full rescan again. A moved-from table kept the index
of the text it gave away, and Insert now updates that index in place,
producing ranges past the end of its buffer.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
- PieceTable::Insert/Delete adjust a valid line index directly (shift
later line starts, add or drop starts for inserted or deleted
newlines) instead of invalidating it, which forced a byte-by-byte
rescan of the whole buffer on the next line query. On a 38 MB,
1M-line buffer, insert + line query drops from 14.7 ms to 0.28 ms.
- The terminal and ImGui renderers fetch only the rows they draw
(Nrows + GetLineString) instead of Buffer::Rows(), which rebuilt a
string for every line of the file on the first frame after each edit.
Qt's line-count uses switch to Nrows().
ImGuiRenderer.cc was syntax-checked with g++ and clang++ against the
vendored ImGui headers; the GUI targets could not be built here (no
SDL2 or Qt6).
Audit findings P1, P2.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
Copy/move assignment kept the destination's line index, so closing a
buffer (vector erase move-assigns later buffers down) left the shifted
buffer with its predecessor's line offsets and out-of-bounds line views.
Appends that merged into an existing piece also skipped invalidation.
Audit findings M1, B12.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
- Introduced comprehensive tests:
- `test_buffer_open_nonexistent_save.cc`: Save after opening a non-existent file.
- `test_buffer_save.cc`: Save buffer contents to disk.
- `test_buffer_save_existing.cc`: Save after opening existing files.
- Implemented `PieceTable::WriteToStream()` to directly stream content without full materialization.
- Updated `Buffer::Save` and `Buffer::SaveAs` to use efficient streaming via `PieceTable`.
- Enhanced editing commands (`Insert`, `Delete`, `Replace`, etc.) to use PieceTable APIs, ensuring proper undo and save functionality.
- Created `piece-table-migration.md` outlining the steps to transition from GapBuffer to a unified PieceTable architecture.
- Included phased approach: extending PieceTable, Buffer adapter layer, command updates, and renderer changes.
- Detailed API changes, file updates, testing strategy, risk assessment, and timeline for each migration phase.
- Document serves as a reference for architecture goals and implementation details.
- Added `PieceTable` class for efficient text manipulation and implemented core editing APIs (`Insert`, `Delete`, `Find`, etc.).
- Integrated `PieceTable` into `Buffer` class with an adapter for rows caching.
- Enabled seamless switching between legacy row-based and new PieceTable-backed editing via `KTE_USE_BUFFER_PIECE_TABLE`.
- Updated file I/O, line-based queries, and cursor operations to support PieceTable-based storage.
- Lazy rebuilding of line index and improved management of edit state for performance.
Claude
kyle