Use file to pass arguments to the shell.

mojo/devtools/common/devtoolslib/android_shell.py

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import atexit
 import hashlib
 import json
 import logging
 import os
 import os.path
 import random
 import re
 import subprocess
 import sys
 import tempfile
 import threading
 import time
+import uuid
 
 from devtoolslib.http_server import start_http_server
 from devtoolslib.shell import Shell
 from devtoolslib.utils import overrides
 
 
 # Tags used by mojo shell Java logging.
 _LOGCAT_JAVA_TAGS = [
     'AndroidHandler',
     'MojoFileHelper',
@@ skipping 314 matching lines @@
             ['shell', 'rm', '-f', STDOUT_PIPE]))
 
         parameters.append('--fifo-path=%s' % STDOUT_PIPE)
         self._read_fifo(STDOUT_PIPE, stdout, on_application_stop)
       else:
         _logger.warning("Running without root access, full stdout of the "
                         "shell won't be available.")
     parameters.extend(arguments)
 
     if parameters:
-      encodedParameters = json.dumps(parameters)
-      cmd += ['--es', 'encodedParameters', encodedParameters]
+      device_filename = (
+          '/sdcard/%s/%s' % (_MOJO_SHELL_PACKAGE_NAME, str(uuid.uuid4())))

[ppi, 2015/10/29 16:27:40]

Should we push this to some /cache/ folder so that these files can be easily
cleaned up if they leak?

[ppi, 2015/10/29 16:27:40]

can you append or prepend "mojo_shell_args" to the name in case anybody ever
looks at these files?

[qsr, 2015/10/29 16:57:02]

Not that I know of. Cache folder are in the app own directory, so they are not
accessible on non-rooted device.

[qsr, 2015/10/29 16:57:02]

It is already in a folder with the shell package name. So I just prepended args_

+      with tempfile.NamedTemporaryFile(delete=False) as temp:
+        try:
+          for parameter in parameters:
+            temp.write(parameter)
+            temp.write('\n')
+          temp.close()
+          subprocess.check_call(self._adb_command(
+              ['push', temp.name, device_filename]))
+        finally:
+          os.remove(temp.name)
+
+      cmd += ['--es', 'parametersFile', device_filename]

[ppi, 2015/10/29 16:27:40]

Should we call it argsFile for consistency?

[qsr, 2015/10/29 16:57:02]

Done.

 
     subprocess.check_call(cmd, stdout=self.verbose_pipe)
 
   def stop_shell(self):
     """Stops the mojo shell."""
     subprocess.check_call(self._adb_command(['shell',
                                             'am',
                                             'force-stop',
                                             _MOJO_SHELL_PACKAGE_NAME]))
 
@@ skipping 94 matching lines @@
           Results.output = rf.read()
 
     run_thread = threading.Thread(target=do_run)
     run_thread.start()
     run_thread.join(timeout)
 
     if run_thread.is_alive():
       self.stop_shell()
       return None, Results.output, True
     return None, Results.output, False