2 files changed, 210 insertions, 0 deletions
diff --git a/runtime/js/40_spawn.js b/runtime/js/40_spawn.js
new file mode 100644
index 000000000..c55ce657d
--- /dev/null
+++ b/runtime/js/40_spawn.js
@@ -0,0 +1,206 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+"use strict";
+
+((window) => {
+  const core = window.Deno.core;
+  const { pathFromURL } = window.__bootstrap.util;
+  const { illegalConstructorKey } = window.__bootstrap.webUtil;
+  const {
+    ArrayPrototypeMap,
+    ObjectEntries,
+    String,
+    TypeError,
+    Uint8Array,
+    PromiseAll,
+  } = window.__bootstrap.primordials;
+  const { readableStreamForRid, writableStreamForRid } =
+    window.__bootstrap.streamUtils;
+
+  function spawnChild(command, {
+    args = [],
+    cwd = undefined,
+    clearEnv = false,
+    env = {},
+    uid = undefined,
+    gid = undefined,
+    stdin = "null",
+    stdout = "piped",
+    stderr = "piped",
+  } = {}) {
+    const child = core.opSync("op_spawn_child", {
+      cmd: pathFromURL(command),
+      args: ArrayPrototypeMap(args, String),
+      cwd: pathFromURL(cwd),
+      clearEnv,
+      env: ObjectEntries(env),
+      uid,
+      gid,
+      stdin,
+      stdout,
+      stderr,
+    });
+    return new Child(illegalConstructorKey, child);
+  }
+
+  async function collectOutput(readableStream) {
+    if (!(readableStream instanceof ReadableStream)) {
+      return null;
+    }
+
+    const bufs = [];
+    let size = 0;
+    for await (const chunk of readableStream) {
+      bufs.push(chunk);
+      size += chunk.byteLength;
+    }
+
+    const buffer = new Uint8Array(size);
+    let offset = 0;
+    for (const chunk of bufs) {
+      buffer.set(chunk, offset);
+      offset += chunk.byteLength;
+    }
+
+    return buffer;
+  }
+
+  class Child {
+    #rid;
+
+    #pid;
+    get pid() {
+      return this.#pid;
+    }
+
+    #stdinRid;
+    #stdin = null;
+    get stdin() {
+      return this.#stdin;
+    }
+
+    #stdoutRid;
+    #stdout = null;
+    get stdout() {
+      return this.#stdout;
+    }
+
+    #stderrRid;
+    #stderr = null;
+    get stderr() {
+      return this.#stderr;
+    }
+
+    constructor(key = null, {
+      rid,
+      pid,
+      stdinRid,
+      stdoutRid,
+      stderrRid,
+    } = null) {
+      if (key !== illegalConstructorKey) {
+        throw new TypeError("Illegal constructor.");
+      }
+
+      this.#rid = rid;
+      this.#pid = pid;
+
+      if (stdinRid !== null) {
+        this.#stdinRid = stdinRid;
+        this.#stdin = writableStreamForRid(stdinRid);
+      }
+
+      if (stdoutRid !== null) {
+        this.#stdoutRid = stdoutRid;
+        this.#stdout = readableStreamForRid(stdoutRid);
+      }
+
+      if (stderrRid !== null) {
+        this.#stderrRid = stderrRid;
+        this.#stderr = readableStreamForRid(stderrRid);
+      }
+
+      this.#status = core.opAsync("op_spawn_wait", this.#rid).then((res) => {
+        this.#rid = null;
+        return res;
+      });
+    }
+
+    #status;
+    get status() {
+      return this.#status;
+    }
+
+    async output() {
+      if (this.#rid === null) {
+        throw new TypeError("Child process has already terminated.");
+      }
+      if (this.#stdout?.locked) {
+        throw new TypeError(
+          "Can't collect output because stdout is locked",
+        );
+      }
+      if (this.#stderr?.locked) {
+        throw new TypeError(
+          "Can't collect output because stderr is locked",
+        );
+      }
+
+      const [status, stdout, stderr] = await PromiseAll([
+        this.#status,
+        collectOutput(this.#stdout),
+        collectOutput(this.#stderr),
+      ]);
+
+      return {
+        status,
+        stdout,
+        stderr,
+      };
+    }
+
+    kill(signo) {
+      if (this.#rid === null) {
+        throw new TypeError("Child process has already terminated.");
+      }
+      core.opSync("op_kill", this.#pid, signo);
+    }
+  }
+
+  function spawn(command, options) { // TODO(@crowlKats): more options (like input)?
+    return spawnChild(command, {
+      ...options,
+      stdin: "null",
+      stdout: "piped",
+      stderr: "piped",
+    }).output();
+  }
+
+  function spawnSync(command, {
+    args = [],
+    cwd = undefined,
+    clearEnv = false,
+    env = {},
+    uid = undefined,
+    gid = undefined,
+  } = {}) { // TODO(@crowlKats): more options (like input)?
+    return core.opSync("op_spawn_sync", {
+      cmd: pathFromURL(command),
+      args: ArrayPrototypeMap(args, String),
+      cwd: pathFromURL(cwd),
+      clearEnv,
+      env: ObjectEntries(env),
+      uid,
+      gid,
+      stdin: "null",
+      stdout: "piped",
+      stderr: "piped",
+    });
+  }
+
+  window.__bootstrap.spawn = {
+    Child,
+    spawnChild,
+    spawn,
+    spawnSync,
+  };
+})(this);
diff --git a/runtime/js/90_deno_ns.js b/runtime/js/90_deno_ns.js
index ddaecd7c9..61e894f8a 100644
--- a/runtime/js/90_deno_ns.js
+++ b/runtime/js/90_deno_ns.js
@@ -151,5 +151,9 @@
     funlockSync: __bootstrap.fs.funlockSync,
     refTimer: __bootstrap.timers.refTimer,
     unrefTimer: __bootstrap.timers.unrefTimer,
+    Child: __bootstrap.spawn.Child,
+    spawnChild: __bootstrap.spawn.spawnChild,
+    spawn: __bootstrap.spawn.spawn,
+    spawnSync: __bootstrap.spawn.spawnSync,
   };
 })(this);