1 files changed, 235 insertions, 0 deletions
diff --git a/cli/js/files.ts b/cli/js/files.ts
new file mode 100644
index 000000000..b83a147e1
--- /dev/null
+++ b/cli/js/files.ts
@@ -0,0 +1,235 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import {
+  EOF,
+  Reader,
+  Writer,
+  Seeker,
+  Closer,
+  SeekMode,
+  SyncReader,
+  SyncWriter,
+  SyncSeeker
+} from "./io.ts";
+import { sendAsyncMinimal, sendSyncMinimal } from "./dispatch_minimal.ts";
+import * as dispatch from "./dispatch.ts";
+import {
+  sendSync as sendSyncJson,
+  sendAsync as sendAsyncJson
+} from "./dispatch_json.ts";
+
+/** Open a file and return an instance of the `File` object
+ *  synchronously.
+ *
+ *       const file = Deno.openSync("/foo/bar.txt");
+ */
+export function openSync(filename: string, mode: OpenMode = "r"): File {
+  const rid = sendSyncJson(dispatch.OP_OPEN, { filename, mode });
+  return new File(rid);
+}
+
+/** Open a file and return an instance of the `File` object.
+ *
+ *       (async () => {
+ *         const file = await Deno.open("/foo/bar.txt");
+ *       })();
+ */
+export async function open(
+  filename: string,
+  mode: OpenMode = "r"
+): Promise<File> {
+  const rid = await sendAsyncJson(dispatch.OP_OPEN, { filename, mode });
+  return new File(rid);
+}
+
+/** Read synchronously from a file ID into an array buffer.
+ *
+ * Return `number | EOF` for the operation.
+ *
+ *      const file = Deno.openSync("/foo/bar.txt");
+ *      const buf = new Uint8Array(100);
+ *      const nread = Deno.readSync(file.rid, buf);
+ *      const text = new TextDecoder().decode(buf);
+ *
+ */
+export function readSync(rid: number, p: Uint8Array): number | EOF {
+  const nread = sendSyncMinimal(dispatch.OP_READ, rid, p);
+  if (nread < 0) {
+    throw new Error("read error");
+  } else if (nread == 0) {
+    return EOF;
+  } else {
+    return nread;
+  }
+}
+
+/** Read from a file ID into an array buffer.
+ *
+ * Resolves with the `number | EOF` for the operation.
+ *
+ *       (async () => {
+ *         const file = await Deno.open("/foo/bar.txt");
+ *         const buf = new Uint8Array(100);
+ *         const nread = await Deno.read(file.rid, buf);
+ *         const text = new TextDecoder().decode(buf);
+ *       })();
+ */
+export async function read(rid: number, p: Uint8Array): Promise<number | EOF> {
+  const nread = await sendAsyncMinimal(dispatch.OP_READ, rid, p);
+  if (nread < 0) {
+    throw new Error("read error");
+  } else if (nread == 0) {
+    return EOF;
+  } else {
+    return nread;
+  }
+}
+
+/** Write synchronously to the file ID the contents of the array buffer.
+ *
+ * Resolves with the number of bytes written.
+ *
+ *       const encoder = new TextEncoder();
+ *       const data = encoder.encode("Hello world\n");
+ *       const file = Deno.openSync("/foo/bar.txt");
+ *       Deno.writeSync(file.rid, data);
+ */
+export function writeSync(rid: number, p: Uint8Array): number {
+  const result = sendSyncMinimal(dispatch.OP_WRITE, rid, p);
+  if (result < 0) {
+    throw new Error("write error");
+  } else {
+    return result;
+  }
+}
+
+/** Write to the file ID the contents of the array buffer.
+ *
+ * Resolves with the number of bytes written.
+ *
+ *      (async () => {
+ *        const encoder = new TextEncoder();
+ *        const data = encoder.encode("Hello world\n");
+ *        const file = await Deno.open("/foo/bar.txt");
+ *        await Deno.write(file.rid, data);
+ *      })();
+ *
+ */
+export async function write(rid: number, p: Uint8Array): Promise<number> {
+  const result = await sendAsyncMinimal(dispatch.OP_WRITE, rid, p);
+  if (result < 0) {
+    throw new Error("write error");
+  } else {
+    return result;
+  }
+}
+
+/** Seek a file ID synchronously to the given offset under mode given by `whence`.
+ *
+ *       const file = Deno.openSync("/foo/bar.txt");
+ *       Deno.seekSync(file.rid, 0, 0);
+ */
+export function seekSync(rid: number, offset: number, whence: SeekMode): void {
+  sendSyncJson(dispatch.OP_SEEK, { rid, offset, whence });
+}
+
+/** Seek a file ID to the given offset under mode given by `whence`.
+ *
+ *      (async () => {
+ *        const file = await Deno.open("/foo/bar.txt");
+ *        await Deno.seek(file.rid, 0, 0);
+ *      })();
+ */
+export async function seek(
+  rid: number,
+  offset: number,
+  whence: SeekMode
+): Promise<void> {
+  await sendAsyncJson(dispatch.OP_SEEK, { rid, offset, whence });
+}
+
+/** Close the file ID. */
+export function close(rid: number): void {
+  sendSyncJson(dispatch.OP_CLOSE, { rid });
+}
+
+/** The Deno abstraction for reading and writing files. */
+export class File
+  implements
+    Reader,
+    SyncReader,
+    Writer,
+    SyncWriter,
+    Seeker,
+    SyncSeeker,
+    Closer {
+  constructor(readonly rid: number) {}
+
+  write(p: Uint8Array): Promise<number> {
+    return write(this.rid, p);
+  }
+
+  writeSync(p: Uint8Array): number {
+    return writeSync(this.rid, p);
+  }
+
+  read(p: Uint8Array): Promise<number | EOF> {
+    return read(this.rid, p);
+  }
+
+  readSync(p: Uint8Array): number | EOF {
+    return readSync(this.rid, p);
+  }
+
+  seek(offset: number, whence: SeekMode): Promise<void> {
+    return seek(this.rid, offset, whence);
+  }
+
+  seekSync(offset: number, whence: SeekMode): void {
+    return seekSync(this.rid, offset, whence);
+  }
+
+  close(): void {
+    close(this.rid);
+  }
+}
+
+/** An instance of `File` for stdin. */
+export const stdin = new File(0);
+/** An instance of `File` for stdout. */
+export const stdout = new File(1);
+/** An instance of `File` for stderr. */
+export const stderr = new File(2);
+
+export type OpenMode =
+  /** Read-only. Default. Starts at beginning of file. */
+  | "r"
+  /** Read-write. Start at beginning of file. */
+  | "r+"
+  /** Write-only. Opens and truncates existing file or creates new one for
+   * writing only.
+   */
+  | "w"
+  /** Read-write. Opens and truncates existing file or creates new one for
+   * writing and reading.
+   */
+  | "w+"
+  /** Write-only. Opens existing file or creates new one. Each write appends
+   * content to the end of file.
+   */
+  | "a"
+  /** Read-write. Behaves like "a" and allows to read from file. */
+  | "a+"
+  /** Write-only. Exclusive create - creates new file only if one doesn't exist
+   * already.
+   */
+  | "x"
+  /** Read-write. Behaves like `x` and allows to read from file. */
+  | "x+";
+
+/** A factory function for creating instances of `File` associated with the
+ * supplied file name.
+ * @internal
+ */
+export function create(filename: string): Promise<File> {
+  return open(filename, "w+");
+}