nvim + pi / bi-directional communication
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234import { mkdir, readFile, rename, stat, unlink, writeFile,} from "node:fs/promises";import { dirname } from "node:path";import { computeUndoHash, contentToUndoLines, undoLineCount } from "./hash";import { parseUndofile } from "./parse";import { DEFAULT_UNDODIR, getUndoFilePath } from "./path";import { serializeUndofile } from "./serialize";import type { Pos, UndoFile, UndoHeader, UpdateUndofileResult } from "./types";
const UH_CHANGED = 0x01;const UHP_SAVE_NR = 1;
export type AppendUndoEntryOptions = { now?: Date;};
type AppendUndoEntryFailureReason = | "hash-mismatch" | "line-count-mismatch" | "unsupported-tree";
type AppendUndoEntryResult = | { ok: true; file: UndoFile } | { ok: false; reason: AppendUndoEntryFailureReason };
function zeroPos(): Pos { return { lnum: 0, col: 0, coladd: 0 };}
function onePos(): Pos { return { lnum: 1, col: 0, coladd: 0 };}
function writeInt32Field(value: number): Buffer { const buffer = Buffer.alloc(4); buffer.writeInt32BE(value); return buffer;}
function findHeader(file: UndoFile, seq: number): UndoHeader | undefined { return file.headers.find((header) => header.seq === seq);}
function validateLatestTree(file: UndoFile): boolean { if (file.curHeadSeq !== 0) return false; if (file.newHeadSeq !== 0 && !findHeader(file, file.newHeadSeq)) return false; if (file.oldHeadSeq !== 0 && !findHeader(file, file.oldHeadSeq)) return false;
const seen = new Set<number>(); for (const header of file.headers) { if (header.seq <= 0 || seen.has(header.seq)) return false; seen.add(header.seq); }
for (const header of file.headers) { for (const seq of [ header.nextSeq, header.prevSeq, header.altNextSeq, header.altPrevSeq, ]) { if (seq !== 0 && !seen.has(seq)) return false; } }
return true;}
export function appendUndoEntryToUndofile( file: UndoFile, oldContent: string, newContent: string, options: AppendUndoEntryOptions = {},): AppendUndoEntryResult { const oldHash = computeUndoHash(oldContent); if (!file.hash.equals(oldHash)) { return { ok: false, reason: "hash-mismatch" }; }
const oldLineCount = undoLineCount(oldContent); if (file.lineCount !== oldLineCount) { return { ok: false, reason: "line-count-mismatch" }; }
if (!validateLatestTree(file)) { return { ok: false, reason: "unsupported-tree" }; }
const newLineCount = undoLineCount(newContent); const newSeq = file.seqLast + 1; const nowSeconds = BigInt( Math.floor((options.now ?? new Date()).getTime() / 1000), ); const oldNewHead = file.newHeadSeq === 0 ? undefined : findHeader(file, file.newHeadSeq); if (file.newHeadSeq !== 0 && !oldNewHead) { return { ok: false, reason: "unsupported-tree" }; } if (oldNewHead && oldNewHead.prevSeq !== 0) { return { ok: false, reason: "unsupported-tree" }; }
if (oldNewHead) { oldNewHead.prevSeq = newSeq; }
const header: UndoHeader = { nextSeq: file.newHeadSeq, prevSeq: 0, altNextSeq: 0, altPrevSeq: 0, seq: newSeq, cursor: onePos(), cursorVcol: -1, flags: UH_CHANGED, namedMarks: Array.from({ length: 26 }, () => zeroPos()), visual: { start: zeroPos(), end: zeroPos(), mode: 0, curswant: 0, }, time: nowSeconds, optionalFields: [{ what: UHP_SAVE_NR, data: writeInt32Field(0) }], entries: [ { top: 0, bot: newLineCount + 1, lcount: oldLineCount, lines: contentToUndoLines(oldContent), }, ], extmarks: [], };
file.headers.push(header); file.hash = computeUndoHash(newContent); file.lineCount = newLineCount; if (file.oldHeadSeq === 0) { file.oldHeadSeq = newSeq; } file.newHeadSeq = newSeq; file.curHeadSeq = 0; file.seqLast = newSeq; file.seqCur = newSeq; file.timeCur = nowSeconds + 1n;
return { ok: true, file };}
export async function updateUndofileForExternalWrite({ filePath, oldContent, newContent, undodir = DEFAULT_UNDODIR,}: { filePath: string; oldContent: string; newContent: string; undodir?: string;}): Promise<UpdateUndofileResult> { if (oldContent.includes("\0") || newContent.includes("\0")) { return { ok: false, reason: "unsupported-content" }; }
const undoFilePath = await getUndoFilePath(filePath, undodir);
let original: Buffer; try { original = await readFile(undoFilePath); } catch (error: unknown) { const code = typeof error === "object" && error !== null && "code" in error ? error.code : undefined; return { ok: false, undoFilePath, reason: code === "ENOENT" ? "missing" : "parse-error", error, }; }
let file: UndoFile; try { file = parseUndofile(original); } catch (error) { return { ok: false, undoFilePath, reason: "parse-error", error }; }
let roundtrip: Buffer; try { roundtrip = serializeUndofile(file); } catch (error) { return { ok: false, undoFilePath, reason: "roundtrip-mismatch", error }; } if (!roundtrip.equals(original)) { return { ok: false, undoFilePath, reason: "roundtrip-mismatch" }; }
let updated: AppendUndoEntryResult; try { updated = appendUndoEntryToUndofile(file, oldContent, newContent); } catch (error) { return { ok: false, undoFilePath, reason: "unsupported-content", error }; }
if (!updated.ok) { return { ok: false, undoFilePath, reason: updated.reason }; }
const next = serializeUndofile(updated.file); const tempPath = `${undoFilePath}.pi-tmp-${process.pid}-${Date.now()}`;
try { const currentStat = await stat(undoFilePath); const currentMode = currentStat.mode & 0o777; await mkdir(dirname(undoFilePath), { recursive: true }); await writeFile(tempPath, next, { mode: currentMode || 0o600 }); await rename(tempPath, undoFilePath); } catch (error) { await unlink(tempPath).catch(() => undefined); return { ok: false, undoFilePath, reason: "write-error", error }; }
return { ok: true, undoFilePath };}