continue/core/diff/util.ts

111 lines
3.2 KiB
TypeScript

import { distance } from "fastest-levenshtein";
import { ChatMessage } from "../index.js";
import { stripImages } from "../llm/images.js";
export type LineStream = AsyncGenerator<string>;
export type MatchLineResult = {
/**
* -1 if it's a new line, otherwise the index of the first match
* in the old lines.
*/
matchIndex: number;
isPerfectMatch: boolean;
newLine: string;
};
function linesMatchPerfectly(lineA: string, lineB: string): boolean {
return lineA === lineB && lineA !== "";
}
const END_BRACKETS = ["}", "});", "})"];
function linesMatch(lineA: string, lineB: string, linesBetween = 0): boolean {
// Require a perfect (without padding) match for these lines
// Otherwise they are edit distance 1 from empty lines and other single char lines (e.g. each other)
if (["}", "*", "});", "})"].includes(lineA.trim())) {
return lineA.trim() === lineB.trim();
}
const d = distance(lineA, lineB);
return (
// Should be more unlikely for lines to fuzzy match if they are further away
(d / Math.max(lineA.length, lineB.length) < 0.5 - linesBetween * 0.05 ||
lineA.trim() === lineB.trim()) &&
lineA.trim() !== ""
);
}
/**
* Used to find a match for a new line in an array of old lines.
*
* Return the index of the first match and whether it is a perfect match
* Also return a version of the line with correct indentation if needs fixing
*/
export function matchLine(
newLine: string,
oldLines: string[],
permissiveAboutIndentation = false,
): MatchLineResult {
// Only match empty lines if it's the next one:
if (newLine.trim() === "" && oldLines[0]?.trim() === "") {
return {
matchIndex: 0,
isPerfectMatch: true,
newLine: newLine.trim(),
};
}
const isEndBracket = END_BRACKETS.includes(newLine.trim());
for (let i = 0; i < oldLines.length; i++) {
// Don't match end bracket lines if too far away
if (i > 4 && isEndBracket) {
return { matchIndex: -1, isPerfectMatch: false, newLine };
}
if (linesMatchPerfectly(newLine, oldLines[i])) {
return { matchIndex: i, isPerfectMatch: true, newLine };
}
if (linesMatch(newLine, oldLines[i], i)) {
// This is a way to fix indentation, but only for sufficiently long lines to avoid matching whitespace or short lines
if (
newLine.trimStart() === oldLines[i].trimStart() &&
(permissiveAboutIndentation || newLine.trim().length > 8)
) {
return {
matchIndex: i,
isPerfectMatch: true,
newLine: oldLines[i],
};
}
return { matchIndex: i, isPerfectMatch: false, newLine };
}
}
return { matchIndex: -1, isPerfectMatch: false, newLine };
}
/**
* Convert a stream of arbitrary chunks to a stream of lines
*/
export async function* streamLines(
streamCompletion: AsyncGenerator<string | ChatMessage>,
): LineStream {
let buffer = "";
for await (const update of streamCompletion) {
const chunk =
typeof update === "string" ? update : stripImages(update.content);
buffer += chunk;
const lines = buffer.split("\n");
buffer = lines.pop() ?? "";
for (const line of lines) {
yield line;
}
}
if (buffer.length > 0) {
yield buffer;
}
}