Refactor run_in_headless_android_emulator.py out of mach test-androi-startup

… and make it more careful about not leaving zombie processes behind.

etc/run_in_headless_android_emulator.py

@@ -0,0 +1,138 @@
+#!/usr/bin/env python
+
+# Copyright 2018 The Servo Project Developers. See the COPYRIGHT
+# file at the top-level directory of this distribution.
+#
+# Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+# http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+# <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+# option. This file may not be copied, modified, or distributed
+# except according to those terms.
+
+import contextlib
+import os
+import signal
+import subprocess
+import sys
+import time
+
+
+def main(avd_name, apk_path, *args):
+    emulator_port = "5580"
+    emulator_args = [
+        tool_path("emulator", "emulator"),
+        "@" + avd_name,
+        "-wipe-data",
+        "-no-window",
+        "-no-snapshot",
+        "-no-snapstorage",
+        "-gpu", "guest",
+        "-port", emulator_port,
+    ]
+    with terminate_on_exit(emulator_args, stdout=sys.stderr) as emulator_process:
+        # This is hopefully enough time for the emulator to exit
+        # if it cannot start because of a configuration problem,
+        # and probably more time than it needs to boot anyway
+        time.sleep(2)
+
+        if emulator_process.poll() is not None:
+            # The emulator process has terminated already,
+            # wait-for-device would block indefinitely
+            print("Emulator did not start")
+            return 1
+
+        adb = [tool_path("platform-tools", "adb"), "-s", "emulator-" + emulator_port]
+
+        with terminate_on_exit(adb + ["wait-for-device"]) as wait_for_device:
+            wait_for_device.wait()
+
+        # Now `adb shell` will work, but `adb install` needs a system service
+        # that might still be in the midle of starting and not be responsive yet.
+
+        # https://stackoverflow.com/a/38896494/1162888
+        while 1:
+            with terminate_on_exit(
+                adb + ["shell", "getprop", "sys.boot_completed"],
+                stdout=subprocess.PIPE,
+            ) as getprop:
+                stdout, stderr = getprop.communicate()
+                if "1" in stdout:
+                    break
+            time.sleep(1)
+
+        check_call(adb + ["install", "-r", apk_path])
+
+        data_dir = "/sdcard/Android/data/com.mozilla.servo/files"
+        params_file = data_dir + "/android_params"
+
+        check_call(adb + ["shell", "mkdir -p %s" % data_dir])
+        check_call(adb + ["shell", "echo 'servo' > %s" % params_file])
+        for arg in args:
+            check_call(adb + ["shell", "echo %s >> %s" % (shell_quote(arg), params_file)])
+
+        check_call(adb + ["shell", "am start com.mozilla.servo/com.mozilla.servo.MainActivity"],
+                   stdout=sys.stderr)
+
+        logcat_args = ["RustAndroidGlueStdouterr:D", "*:S", "-v", "raw"]
+        with terminate_on_exit(adb + ["logcat"] + logcat_args) as logcat:
+            logcat.wait()
+
+
+def tool_path(directory, bin_name):
+    if "ANDROID_SDK" in os.environ:
+        path = os.path.join(os.environ["ANDROID_SDK"], directory, bin_name)
+        if os.path.exists(path):
+            return path
+
+    path = os.path.join(os.path.dirname(__file__), "..", "android-toolchains", "sdk",
+                        directory, bin_name)
+    if os.path.exists(path):
+        return path
+
+    return bin_name
+
+
+@contextlib.contextmanager
+def terminate_on_exit(*args, **kwargs):
+    process = subprocess.Popen(*args, **kwargs)
+    try:
+        yield process
+    finally:
+        if process.poll() is None:
+            # The process seems to be still running
+            process.terminate()
+
+
+def check_call(*args, **kwargs):
+    with terminate_on_exit(*args, **kwargs) as process:
+        exit_code = process.wait()
+        if exit_code != 0:
+            sys.exit(exit_code)
+
+
+# Copied from Python 3.3+'s shlex.quote()
+def shell_quote(arg):
+    # use single quotes, and put single quotes into double quotes
+    # the string $'b is then quoted as '$'"'"'b'
+    return "'" + arg.replace("'", "'\"'\"'") + "'"
+
+
+def interrupt(_signum, _frame):
+    raise KeyboardInterrupt
+
+
+if __name__ == "__main__":
+    if len(sys.argv) < 3:
+        print("Usage: %s avd_name apk_path [servo args...]" % sys.argv[0])
+        print("Example: %s servo-x86 target/i686-linux-android/release/servo.apk https://servo.org"
+              % sys.argv[0])
+        sys.exit(1)
+
+    try:
+        # When `./mach test-android-startup` runs `Popen.terminate()` on this process,
+        # raise an exception in order to make `finally:` blocks run
+        # and also terminate sub-subprocesses.
+        signal.signal(signal.SIGTERM, interrupt)
+        sys.exit(main(*sys.argv[1:]))
+    except KeyboardInterrupt:
+        sys.exit(1)