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std/path/_dirname.ts

Deno standard library
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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
import { CHAR_COLON } from "./_constants.ts";import { assertPath, isPathSeparator, isPosixPathSeparator, isWindowsDeviceRoot, stripTrailingSeparators,} from "./_util.ts";
function assertArg(path: string) { assertPath(path); if (path.length === 0) return ".";}
/** * Return the directory path of a `path`. * @param path - path to extract the directory from. */export function posixDirname(path: string): string { assertArg(path);
let end = -1; let matchedNonSeparator = false;
for (let i = path.length - 1; i >= 1; --i) { if (isPosixPathSeparator(path.charCodeAt(i))) { if (matchedNonSeparator) { end = i; break; } } else { matchedNonSeparator = true; } }
// No matches. Fallback based on provided path: // // - leading slashes paths // "/foo" => "/" // "///foo" => "/" // - no slash path // "foo" => "." if (end === -1) { return isPosixPathSeparator(path.charCodeAt(0)) ? "/" : "."; }
return stripTrailingSeparators( path.slice(0, end), isPosixPathSeparator, );}
/** * Return the directory path of a `path`. * @param path - path to extract the directory from. */export function windowsDirname(path: string): string { assertArg(path);
const len = path.length; let rootEnd = -1; let end = -1; let matchedSlash = true; let offset = 0; const code = path.charCodeAt(0);
// Try to match a root if (len > 1) { if (isPathSeparator(code)) { // Possible UNC root
rootEnd = offset = 1;
if (isPathSeparator(path.charCodeAt(1))) { // Matched double path separator at beginning let j = 2; let last = j; // Match 1 or more non-path separators for (; j < len; ++j) { if (isPathSeparator(path.charCodeAt(j))) break; } if (j < len && j !== last) { // Matched! last = j; // Match 1 or more path separators for (; j < len; ++j) { if (!isPathSeparator(path.charCodeAt(j))) break; } if (j < len && j !== last) { // Matched! last = j; // Match 1 or more non-path separators for (; j < len; ++j) { if (isPathSeparator(path.charCodeAt(j))) break; } if (j === len) { // We matched a UNC root only return path; } if (j !== last) { // We matched a UNC root with leftovers
// Offset by 1 to include the separator after the UNC root to // treat it as a "normal root" on top of a (UNC) root rootEnd = offset = j + 1; } } } } } else if (isWindowsDeviceRoot(code)) { // Possible device root
if (path.charCodeAt(1) === CHAR_COLON) { rootEnd = offset = 2; if (len > 2) { if (isPathSeparator(path.charCodeAt(2))) rootEnd = offset = 3; } } } } else if (isPathSeparator(code)) { // `path` contains just a path separator, exit early to avoid // unnecessary work return path; }
for (let i = len - 1; i >= offset; --i) { if (isPathSeparator(path.charCodeAt(i))) { if (!matchedSlash) { end = i; break; } } else { // We saw the first non-path separator matchedSlash = false; } }
if (end === -1) { if (rootEnd === -1) return "."; else end = rootEnd; } return stripTrailingSeparators(path.slice(0, end), isPosixPathSeparator);}