1 files changed, 198 insertions, 0 deletions
diff --git a/toolkit/modules/subprocess/Subprocess.sys.mjs b/toolkit/modules/subprocess/Subprocess.sys.mjs
new file mode 100644
index 0000000000..ffbeb0acbb
--- /dev/null
+++ b/toolkit/modules/subprocess/Subprocess.sys.mjs
@@ -0,0 +1,198 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * These modules are loosely based on the subprocess.jsm module created
+ * by Jan Gerber and Patrick Brunschwig, though the implementation
+ * differs drastically.
+ */
+
+import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs";
+import { SubprocessConstants } from "resource://gre/modules/subprocess/subprocess_common.sys.mjs";
+
+const lazy = {};
+
+if (AppConstants.platform == "win") {
+  ChromeUtils.defineESModuleGetters(lazy, {
+    SubprocessImpl: "resource://gre/modules/subprocess/subprocess_win.sys.mjs",
+  });
+} else {
+  ChromeUtils.defineESModuleGetters(lazy, {
+    SubprocessImpl: "resource://gre/modules/subprocess/subprocess_unix.sys.mjs",
+  });
+}
+
+function encodeEnvVar(name, value) {
+  if (typeof name === "string" && typeof value === "string") {
+    return `${name}=${value}`;
+  }
+
+  let encoder = new TextEncoder();
+  function encode(val) {
+    return typeof val === "string" ? encoder.encode(val) : val;
+  }
+
+  return Uint8Array.of(...encode(name), ...encode("="), ...encode(value), 0);
+}
+
+function platformSupportsDisclaimedSpawn() {
+  return AppConstants.isPlatformAndVersionAtLeast("macosx", 18);
+}
+
+/**
+ * Allows for creation of and communication with OS-level sub-processes.
+ *
+ * @namespace
+ */
+export var Subprocess = {
+  /**
+   * Launches a process, and returns a handle to it.
+   *
+   * @param {object} options
+   * An object describing the process to launch.
+   *
+   * @param {string} options.command
+   * The full path of the executable to launch. Relative paths are not
+   * accepted, and `$PATH` is not searched.
+   *
+   * If a path search is necessary, the {@link Subprocess.pathSearch} method may
+   * be used to map a bare executable name to a full path.
+   *
+   * @param {string[]} [options.arguments]
+   * A list of strings to pass as arguments to the process.
+   *
+   * @param {object} [options.environment] An object containing a key
+   * and value for each environment variable to pass to the
+   * process. Values that are `=== null` are ignored. Only the
+   * object's own, enumerable properties are added to the environment.
+   *
+   * @param {boolean} [options.environmentAppend] If true, append the
+   * environment variables passed in `environment` to the existing set
+   * of environment variables. Values that are `=== null` are removed
+   * from the environment. Otherwise, the values in 'environment'
+   * constitute the entire set of environment variables passed to the
+   * new process.
+   *
+   * @param {string} [options.stderr]
+   * Defines how the process's stderr output is handled. One of:
+   *
+   * - `"ignore"`: (default) The process's standard error is not redirected.
+   * - `"stdout"`: The process's stderr is merged with its stdout.
+   * - `"pipe"`: The process's stderr is redirected to a pipe, which can be read
+   *   from via its `stderr` property.
+   *
+   * @param {string} [options.workdir]
+   *        The working directory in which to launch the new process.
+   *
+   * @param {boolean} [options.disclaim]
+   * macOS-specific option for 10.14+ OS versions. If true, enables a
+   * macOS-specific process launch option allowing the parent process to
+   * disclaim responsibility for the child process with respect to privacy/
+   * security permission prompts and decisions. This option is ignored on
+   * platforms that do not support it.
+   *
+   * @returns {Promise<Process>}
+   *
+   * @throws {Error}
+   * May be rejected with an Error object if the process can not be
+   * launched. The object will include an `errorCode` property with
+   * one of the following values if it was rejected for the
+   * corresponding reason:
+   *
+   * - Subprocess.ERROR_BAD_EXECUTABLE: The given command could not
+   *   be found, or the file that it references is not executable.
+   *
+   * Note that if the process is successfully launched, but exits with
+   * a non-zero exit code, the promise will still resolve successfully.
+   */
+  call(options) {
+    options = Object.assign({}, options);
+
+    options.stderr = options.stderr || "ignore";
+    options.workdir = options.workdir || null;
+    options.disclaim = options.disclaim || false;
+
+    let environment = {};
+    if (!options.environment || options.environmentAppend) {
+      environment = this.getEnvironment();
+    }
+
+    if (options.environment) {
+      Object.assign(environment, options.environment);
+    }
+
+    options.environment = Object.entries(environment)
+      .map(([key, val]) => (val !== null ? encodeEnvVar(key, val) : null))
+      .filter(s => s);
+
+    options.arguments = Array.from(options.arguments || []);
+
+    if (options.disclaim && !platformSupportsDisclaimedSpawn()) {
+      options.disclaim = false;
+    }
+
+    return Promise.resolve(
+      lazy.SubprocessImpl.isExecutableFile(options.command)
+    ).then(isExecutable => {
+      if (!isExecutable) {
+        let error = new Error(
+          `File at path "${options.command}" does not exist, or is not executable`
+        );
+        error.errorCode = SubprocessConstants.ERROR_BAD_EXECUTABLE;
+        throw error;
+      }
+
+      options.arguments.unshift(options.command);
+
+      return lazy.SubprocessImpl.call(options);
+    });
+  },
+
+  /**
+   * Returns an object with a key-value pair for every variable in the process's
+   * current environment.
+   *
+   * @returns {object}
+   */
+  getEnvironment() {
+    let environment = Object.create(null);
+    for (let [k, v] of lazy.SubprocessImpl.getEnvironment()) {
+      environment[k] = v;
+    }
+    return environment;
+  },
+
+  /**
+   * Searches for the given executable file in the system executable
+   * file paths as specified by the PATH environment variable.
+   *
+   * On Windows, if the unadorned filename cannot be found, the
+   * extensions in the semicolon-separated list in the PATHSEP
+   * environment variable are successively appended to the original
+   * name and searched for in turn.
+   *
+   * @param {string} command
+   *        The name of the executable to find.
+   * @param {object} [environment]
+   *        An object containing a key for each environment variable to be used
+   *        in the search. If not provided, full the current process environment
+   *        is used.
+   * @returns {Promise<string>}
+   */
+  pathSearch(command, environment = this.getEnvironment()) {
+    // Promise.resolve lets us get around returning one of the Promise.jsm
+    // pseudo-promises returned by Task.jsm.
+    let path = lazy.SubprocessImpl.pathSearch(command, environment);
+    return Promise.resolve(path);
+  },
+};
+
+Object.assign(Subprocess, SubprocessConstants);
+Object.freeze(Subprocess);
+
+export function getSubprocessImplForTest() {
+  return lazy.SubprocessImpl;
+}