Add support for building the Dart VM for Android OS.

runtime/tools/android_finder.py

+#!/usr/bin/env python
+
+# Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+
+"""
+Find an Android device with a given ABI

[ahe, 2012/08/30 10:24:10]

Missing period.

[jackpal, 2012/08/30 18:25:20]

Done.

+
+The name of the Android device is printed to stdout

[ahe, 2012/08/30 10:24:10]

Missing period.

[jackpal, 2012/08/30 18:25:20]

Done.

+
+Optionally configure and launch an emulator if there's no existing device for a
+given ABI. Will download and install Android SDK components as needed.
+"""
+
+import optparse
+import os
+import re
+import sys
+import traceback
+import utils
+
+
+DEBUG = False
+VERBOSE = False
+
+
+def BuildOptions():
+  result = optparse.OptionParser()
+  result.add_option(
+      "-a", "--abi",
+      action="store", type="string",
+      help="Desired ABI. armeabi-v7a or x86")

[ahe, 2012/08/30 10:24:10]

Missing period.

[jackpal, 2012/08/30 18:25:20]

Done.

+  result.add_option(
+      "-b", "--bootstrap",
+      help='Bootstrap - create an emulator, installing SDK packages if needed.',
+      default=False, action="store_true")
+  result.add_option(
+      "-d", "--debug",
+      help='Turn on debugging diagnostics.',
+      default=False, action="store_true")
+  result.add_option(
+      "-v", "--verbose",
+      help='Verbose output.',
+      default=False, action="store_true")
+  return result
+
+
+def ProcessOptions(options):
+  global DEBUG
+  DEBUG = options.debug
+  global VERBOSE
+  VERBOSE = options.verbose
+  if options.abi is None:
+    sys.stderr.write('--abi not specified\n')

[ahe, 2012/08/30 10:24:10]

Missing period.

[ahe, 2012/08/30 10:24:10]

FYI: I just discovered this alternative:

print >> sys.stderr, '--abi not specified.'

[jackpal, 2012/08/30 18:25:20]

Interesting! I read on stack overflow that one benefit of using print >>
sys.stderr is that the print statement performs automatic coercion of the
arguments to strings. I'll think about using it instead of sys.stderr.write in
the future.

On 2012/08/30 10:24:10, ahe wrote:

+    return False
+  return True
+
+
+def ParseAndroidListSdkResult(text):
+  """
+  Parse the output of an 'android list sdk' command.
+
+  Return list of (id-num, id-key, type, description)

[ahe, 2012/08/30 10:24:10]

Missing period.

[jackpal, 2012/08/30 18:25:20]

Done.

+  """
+  header_regex = re.compile(
+      r'Packages available for installation or update: \d+\n')
+  packages = re.split(header_regex, text)
+  if len(packages) != 2:
+    raise Exception("Could not get a list of packages to install")
+  entry_regex = re.compile(
+      r'^id\: (\d+) or "([^"]*)"\n\s*Type\: ([^\n]*)\n\s*Desc\: (.*)')
+  entries = []
+  for entry in packages[1].split('----------\n'):
+    match = entry_regex.match(entry)
+    if match == None:
+      continue
+    entries.append((int(match.group(1)), match.group(2), match.group(3),
+        match.group(4)))
+  return entries
+
+
+def AndroidListSdk():
+  return ParseAndroidListSdkResult(utils.RunCommand(
+      ["android", "list", "sdk", "-a", "-e"]))

[ahe, 2012/08/30 10:24:10]

I assume you already checked that there is no "machine readable" output from
this command?

[jackpal, 2012/08/30 18:25:20]

Yeah, unfortunately the "android" tool wasn't designed with an eye towards being
easy to script.

+
+
+def AndroidSdkFindPackage(packages, key):
+  """key is (id-key, type, description-prefix)"""

[ahe, 2012/08/30 10:24:10]

If you want symbolic names instead of indexing, I think you can write:

(id_key, type, description_prefix) = key

[jackpal, 2012/08/30 18:25:20]

Done.

+  for package in packages:

[ahe, 2012/08/30 10:24:10]

And here I think you can write this:

for (i, t, d) in packages:

[jackpal, 2012/08/30 18:25:20]

Well, I want to return the package in line 93, so I think it's better to keep
line 90 the way it is now.

But I'll add a destructuring assignment to make lines 91 and 92 clearer. 

+    if (package[1] == key[0] and package[2] == key[1]
+        and package[3].find(key[2]) == 0):
+      return package
+  return None
+
+
+def EnsureSdkPackageInstalled(packages, key):
+  """
+  Makes sure the package with a given key is installed.
+
+  key is (id-key, type, description-prefix)
+
+  Returns True if the package was not already installed.
+  """
+  entry = AndroidSdkFindPackage(packages, key)
+  if entry is None:
+    raise Exception("Could not find a package for key %s" % key)
+  packageId = entry[0]
+  if VERBOSE:
+    sys.stderr.write('Checking Android SDK package %s...\n' % str(entry))

[ahe, 2012/08/30 10:24:10]

Why is verbose output written to stderr?

[jackpal, 2012/08/30 18:25:20]

To avoid polluting stdout, which is where we return the name of the environment
we've found.

+  out = utils.RunCommand(
+      ["android", "update", "sdk", "-a", "-u", "--filter", str(packageId)])
+  return out.find('\nInstalling Archives:\n') >= 0

[ahe, 2012/08/30 10:24:10]

return '\nInstalling Archives:\n' in out

[jackpal, 2012/08/30 18:25:20]

Sweet!

+
+
+def SdkPackagesForAbi(abi):
+  packagesForAbi = {
+    'armeabi-v7a': [
+      # The platform needed to install the armeabi ABI system image:
+      ('android-15', 'Platform',  'Android SDK Platform 4.0.3'),
+      # The armeabi-v7a ABI system image:
+      ('sysimg-15', 'SystemImage',  'Android SDK Platform 4.0.3')
+    ],
+    'x86': [
+      # The platform needed to install the x86 ABI system image:
+      ('android-15', 'Platform',  'Android SDK Platform 4.0.3'),
+      # The x86 ABI system image:
+      ('sysimg-15', 'SystemImage',  'Android SDK Platform 4.0.4')
+    ]
+  }
+
+  if abi not in packagesForAbi:
+    raise Exception('Unsupported abi %s' % abi)
+  return packagesForAbi[abi]
+
+
+def TargetForAbi(abi):
+  for package in SdkPackagesForAbi(abi):
+    if package[1] == 'Platform':
+      return package[0]
+

[ahe, 2012/08/30 10:24:10]

Missing newline.

[jackpal, 2012/08/30 18:25:20]

Done.

+def EnsureAndroidSdkPackagesInstalled(abi):
+  """Return true if at least one package was not already installed."""
+  abiPackageList = SdkPackagesForAbi(abi)
+  installedSomething = False
+  packages = AndroidListSdk()
+  for package in abiPackageList:
+    installedSomething |= EnsureSdkPackageInstalled(packages, package)
+  return installedSomething
+
+
+def ParseAndroidListAvdResult(text):
+  """
+  Parse the output of an 'android list avd' command.
+  Return List of {Name: Path: Target: ABI: Skin: Sdcard:}
+  """
+  text = text.split('Available Android Virtual Devices:\n')[-1]
+  text = text.split(
+      'The following Android Virtual Devices could not be loaded:\n')[0]
+  result = []
+  line_re = re.compile(r'^\s*([^\:]+)\:\s*(.*)$')
+  for chunk in text.split('\n---------\n'):
+    entry = {}
+    for line in chunk.split('\n'):
+      line = line.strip()
+      if len(line) == 0:
+        continue
+      match = line_re.match(line)
+      if match is None:
+        raise Exception('Match failed')
+      entry[match.group(1)] = match.group(2)
+    if len(entry) > 0:
+      result.append(entry)
+  return result
+
+
+def AndroidListAvd():
+  """Returns a list of available Android Virtual Devices."""
+  return ParseAndroidListAvdResult(utils.RunCommand(["android", "list", "avd"]))
+
+
+def FindAvd(avds, key):
+  for avd in avds:
+    if avd['Name'] == key:
+      return avd
+  return None
+
+
+def CreateAvd(avdName, abi):
+  out = utils.RunCommand(["android", "create", "avd", "--name", avdName,
+                          "--target", TargetForAbi(abi), '--abi', abi],
+                         input="no\n")
+  if out.find('Created AVD ') < 0:
+    if VERBOSE:
+        sys.stderr.write('Could not create AVD:\n%s\n' % out)
+    raise Exception('Could not create AVD')
+
+
+def AvdExists(avdName):
+  avdList = AndroidListAvd()
+  return FindAvd(avdList, avdName) is not None
+
+
+def EnsureAvdExists(avdName, abi):
+  if AvdExists(avdName):
+    return
+  if VERBOSE:
+    sys.stderr.write('Checking SDK packages...\n')
+  if EnsureAndroidSdkPackagesInstalled(abi):
+    # Installing a new package could have made a previously invalid AVD valid
+    if AvdExists(avdName):
+        return
+  CreateAvd(avdName, abi)
+

[ahe, 2012/08/30 10:24:10]

Missing newline.

+def dumpenv(map):

[ahe, 2012/08/30 10:24:10]

Inconsistent name.

[jackpal, 2012/08/30 18:25:20]

Oops! - this is unused debugging code, I'll remove it entirely.

+  e = map.keys()
+  e.sort()
+  for k in e:
+    sys.stderr.write("%s: %s\n" % (k, map[k]))
+
+
+def StartEmulator(abi, avdName, pollFn):
+  """
+  Start an emulator for a given abi and svdName.
+
+  Echo the emulator's stderr and stdout output to our stderr.
+
+  Call pollFn repeatedly until it returns False. Leave the emulator running
+  when we return.
+
+  Implementation note: Normally we would call the 'emulator' binary, which
+  is a wrapper that launches the appropriate abi-specific emulator. But there
+  is a bug that causes the emulator to exit immediately with a result code of
+  -11 if run from a ssh shell or a NX Machine shell. (And only if called from
+  three levels of nested python scripts.) Calling the ABI-specific versions
+  of the emulator directly works around this bug.
+  """
+  emulatorName = {'x86' : 'emulator-x86', 'armeabi-v7a': 'emulator-arm'}[abi]
+  command = [emulatorName, '-avd', avdName, '-no-boot-anim', '-no-window']
+  utils.RunCommand(command, pollFn=pollFn, killOnEarlyReturn=False,
+          outStream=sys.stderr, errStream=sys.stderr)
+
+
+def ParseAndroidDevices(text):
+  """Return Dictionary [name] -> status"""
+  text = text.split('List of devices attached')[-1]
+  lines = [line.strip() for line in text.split('\n')]
+  lines = [line for line in lines if len(line) > 0]
+  devices = {}
+  for line in lines:
+    lineItems = line.split('\t')
+    devices[lineItems[0]] = lineItems[1]
+  return devices
+
+
+def GetAndroidDevices():
+  return ParseAndroidDevices(utils.RunCommand(["adb", "devices"]))
+
+
+def FilterOfflineDevices(devices):
+  online = {}
+  for device in devices.keys():
+    status = devices[device]
+    if status != 'offline':
+      online[device] = status
+  return online
+
+
+def GetOnlineAndroidDevices():
+  return FilterOfflineDevices(GetAndroidDevices())
+
+
+def GetAndroidDeviceProperty(device, property):
+  return utils.RunCommand(
+      ["adb", "-s", device, "shell", "getprop", property]).strip()
+
+
+def GetAndroidDeviceAbis(device):
+  abis = []
+  for property in ['ro.product.cpu.abi', 'ro.product.cpu.abi2']:
+    out = GetAndroidDeviceProperty(device, property)
+    if len(out) > 0:
+      abis.append(out)
+  return abis
+
+
+def FindAndroidRunning(abi):
+  for device in GetOnlineAndroidDevices().keys():
+    if abi in GetAndroidDeviceAbis(device):
+      return device
+  return None
+
+
+def AddSdkToolsToPath():
+  script_dir = os.path.dirname(sys.argv[0])
+  dart_root = os.path.realpath(os.path.join(script_dir, '..', '..'))
+  third_party_root = os.path.join(dart_root, 'third_party')
+  android_tools = os.path.join(third_party_root, 'android_tools')
+  android_sdk_root = os.path.join(android_tools, 'sdk')
+  android_sdk_tools = os.path.join(android_sdk_root, 'tools')
+  android_sdk_platform_tools = os.path.join(android_sdk_root, 'platform-tools')
+  os.environ['PATH'] = ':'.join([
+      os.environ['PATH'], android_sdk_tools, android_sdk_platform_tools])
+  # Remove any environment variables that would affect our build.
+  for i in ['ANDROID_NDK_ROOT', 'ANDROID_SDK_ROOT', 'ANDROID_TOOLCHAIN',
+            'AR', 'BUILDTYPE', 'CC', 'CXX', 'GYP_DEFINES',
+            'LD_LIBRARY_PATH', 'LINK', 'MAKEFLAGS', 'MAKELEVEL',
+            'MAKEOVERRIDES', 'MFLAGS', 'NM']:
+    if i in os.environ:
+      del os.environ[i]
+

[ahe, 2012/08/30 10:24:10]

Missing newline.

[jackpal, 2012/08/30 18:25:20]

Done.

+def FindAndroid(abi, bootstrap):
+  if VERBOSE:
+    sys.stderr.write('Looking for an Android device running abi %s...\n' % abi)
+  AddSdkToolsToPath()
+  device = FindAndroidRunning(abi)
+  if device is None:

[ahe, 2012/08/30 10:24:10]

if not device:

[jackpal, 2012/08/30 18:25:20]

Done.

+    if bootstrap:
+      if VERBOSE:
+        sys.stderr.write("No emulator found, try to create one.\n")
+      avdName = 'dart-build-%s' % abi
+      EnsureAvdExists(avdName, abi)
+
+      # It takes a while to start up an emulator.
+      # Provide feedback while we wait.
+      pollResult = [None]
+      def pollFunction():
+        if VERBOSE:
+          sys.stderr.write('.')
+        pollResult[0] = FindAndroidRunning(abi)
+        # Stop polling once we have our result.
+        return pollResult[0] != None
+      StartEmulator(abi, avdName, pollFunction)
+      device = pollResult[0]
+  return device
+
+
+def Main():
+  # Parse options.
+  parser = BuildOptions()
+  (options, args) = parser.parse_args()
+  if not ProcessOptions(options):
+    parser.print_help()
+    return 1
+
+  # If there are additional arguments, report error and exit.
+  if args:
+    parser.print_help()
+    return 1
+
+  try:
+    device = FindAndroid(options.abi, options.bootstrap)
+    if device != None:
+      sys.stdout.write("%s\n" % device)
+      return 0
+    else:
+      if VERBOSE:
+        sys.stderr.write('Could not find device\n')
+      return 2
+  except Exception as e:

[ahe, 2012/08/30 10:24:10]

I think this is problematic. It also catches, for example, SyntaxError.

I'm aware that we're following PEP-8, not Google's style guide. However, I think
Google's style guide offers some great advice on how to use exceptions in
Python:
http://google-styleguide.googlecode.com/svn/trunk/pyguide.html#Exceptions

In short: define your own exception class and raise that instead of Exception.

[jackpal, 2012/08/30 18:25:20]

Done.

+    sys.stderr.write("error: %s\n" % e)
+    if DEBUG:
+      traceback.print_exc(file=sys.stderr)
+    return -1
+
+
+if __name__ == '__main__':
+  sys.exit(Main())