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import { ensureDir } from "https://deno.land/std@0.145.0/fs/ensure_dir.ts";import { join } from "https://deno.land/std@0.145.0/path/mod.ts";
/** download and cache remote contents */export async function cache(  url: string,): Promise<{ content: Uint8Array; contentType: string | null }> {  const { protocol, hostname, port, pathname, search } = new URL(url);  const isLocalhost = ["0.0.0.0", "127.0.0.1", "localhost"].includes(hostname);  const cacheDir = join(    await getDenoDir(),    "deps",    protocol.replace(":", ""),    hostname + (port ? "_PORT" + port : ""),  );  const hashname = toHex(    await crypto.subtle.digest(      "sha-256",      new TextEncoder().encode(pathname + search),    ),  );  const contentFilepath = join(cacheDir, hashname);  const metaFilepath = join(cacheDir, hashname + ".metadata.json");
  if (    !isLocalhost &&    await existsFile(contentFilepath) &&    await existsFile(metaFilepath)  ) {    const [content, meta] = await Promise.all([      Deno.readFile(contentFilepath),      Deno.readTextFile(metaFilepath),    ]);    try {      const { headers = {} } = JSON.parse(meta);      return {        content,        contentType: headers["content-type"] || null,      };    } catch (_e) {      // ignore    }  }
  const retryTimes = 3;  let err = new Error("Unknown");  for (let i = 0; i < retryTimes; i++) {    try {      const resp = await fetch(url);      if (resp.status >= 400) {        err = new Error(resp.statusText);        continue;      }      const buffer = await resp.arrayBuffer();      const content = new Uint8Array(buffer);      if (!isLocalhost) {        const headers: Record<string, string> = {};        resp.headers.forEach((val, key) => {          headers[key] = val;        });        await ensureDir(cacheDir);        await Promise.all([          Deno.writeFile(contentFilepath, content),          Deno.writeTextFile(            metaFilepath,            JSON.stringify(              { headers, url, createdAt: Date.now() },              undefined,              2,            ),          ),        ]);      }      return {        content,        contentType: resp.headers.get("content-type"),      };    } catch (e) {      err = e;    }  }
  return Promise.reject(err);}
function toHex(buffer: ArrayBuffer) {  const bytes = new Uint8Array(buffer);  return [...bytes].map((b) => b.toString(16).padStart(2, "0")).join("");}
/** get the deno cache dir. */async function getDenoDir() {  const p = Deno.run({    cmd: [Deno.execPath(), "info", "--json"],    stdout: "piped",    stderr: "null",  });  const output = new TextDecoder().decode(await p.output());  const { denoDir } = JSON.parse(output);  p.close();  if (denoDir === undefined || !await existsDir(denoDir)) {    throw new Error(`can"t find the deno dir`);  }  return denoDir;}
/* check whether or not the given path exists as a directory. */async function existsDir(path: string): Promise<boolean> {  try {    const fi = await Deno.lstat(path);    if (fi.isDirectory) {      return true;    }    return false;  } catch (err) {    if (err instanceof Deno.errors.NotFound) {      return false;    }    throw err;  }}
/* check whether or not the given path exists as regular file. */async function existsFile(path: string): Promise<boolean> {  try {    const fi = await Deno.lstat(path);    if (fi.isFile) {      return true;    }    return false;  } catch (err) {    if (err instanceof Deno.errors.NotFound) {      return false;    }    throw err;  }}