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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
import { CHAR_DOT } from "../_common/constants.ts";import type { ParsedPath } from "../_interface.ts";import { stripTrailingSeparators } from "../_common/strip_trailing_separators.ts";import { assertPath } from "../_common/assert_path.ts";import { isPosixPathSeparator } from "./_util.ts";
export type { ParsedPath } from "../_interface.ts";
/** * Return a `ParsedPath` object of the `path`. * @param path to process */export function parse(path: string): ParsedPath {  assertPath(path);
  const ret: ParsedPath = { root: "", dir: "", base: "", ext: "", name: "" };  if (path.length === 0) return ret;  const isAbsolute = isPosixPathSeparator(path.charCodeAt(0));  let start: number;  if (isAbsolute) {    ret.root = "/";    start = 1;  } else {    start = 0;  }  let startDot = -1;  let startPart = 0;  let end = -1;  let matchedSlash = true;  let i = path.length - 1;
  // Track the state of characters (if any) we see before our first dot and  // after any path separator we find  let preDotState = 0;
  // Get non-dir info  for (; i >= start; --i) {    const code = path.charCodeAt(i);    if (isPosixPathSeparator(code)) {      // If we reached a path separator that was not part of a set of path      // separators at the end of the string, stop now      if (!matchedSlash) {        startPart = i + 1;        break;      }      continue;    }    if (end === -1) {      // We saw the first non-path separator, mark this as the end of our      // extension      matchedSlash = false;      end = i + 1;    }    if (code === CHAR_DOT) {      // If this is our first dot, mark it as the start of our extension      if (startDot === -1) startDot = i;      else if (preDotState !== 1) preDotState = 1;    } else if (startDot !== -1) {      // We saw a non-dot and non-path separator before our dot, so we should      // have a good chance at having a non-empty extension      preDotState = -1;    }  }
  if (    startDot === -1 ||    end === -1 ||    // We saw a non-dot character immediately before the dot    preDotState === 0 ||    // The (right-most) trimmed path component is exactly '..'    (preDotState === 1 && startDot === end - 1 && startDot === startPart + 1)  ) {    if (end !== -1) {      if (startPart === 0 && isAbsolute) {        ret.base = ret.name = path.slice(1, end);      } else {        ret.base = ret.name = path.slice(startPart, end);      }    }    // Fallback to '/' in case there is no basename    ret.base = ret.base || "/";  } else {    if (startPart === 0 && isAbsolute) {      ret.name = path.slice(1, startDot);      ret.base = path.slice(1, end);    } else {      ret.name = path.slice(startPart, startDot);      ret.base = path.slice(startPart, end);    }    ret.ext = path.slice(startDot, end);  }
  if (startPart > 0) {    ret.dir = stripTrailingSeparators(      path.slice(0, startPart - 1),      isPosixPathSeparator,    );  } else if (isAbsolute) ret.dir = "/";
  return ret;}