Download arm sysroot as part of gclient hooks

build/linux/install-arm-sysroot.py

+#!/usr/bin/env python
+# Copyright (c) 2012 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.
+
+# Script to install arm choot image for cross building of arm chrome on linux.
+# This script can be run manually but is more often run as part of gclient
+# hooks. When run from hooks this script should be a no-op on non-linux
+# platforms.
+
+# The sysroot image could be constructed from scratch based on the current
+# state or precise/arm but for consistency we currently use a pre-built root
+# image which was originally designed for building trusted NaCl code. The image
+# will normally need to be rebuilt every time chrome's build dependancies are
+# changed.
+
+import os
+import sys
+
+
+script_dir = os.path.dirname(os.path.abspath(__file__))

[iannucci, 2012/12/07 22:43:39]

nit: I would upcase SCRIPT_DIR

[Sam Clegg, 2012/12/07 23:39:19]

Done.

+
+
+def main(args):
+  if '--linux-only' in args:
+    # This argument is passed when run from the gclient hooks.
+    # In this case we return early on non-linux platforms
+    # or if GYP_DEFINES doesn't include target_arch=arm
+    if not sys.platform.startswith('linux'):
+      return 0
+
+    if "target_arch=arm" not in os.environ.get('GYP_DEFINES', ''):
+      return 0
+
+  src_root = os.path.dirname(os.path.dirname(script_dir))
+  sysroot = os.path.join(src_root, 'arm-sysroot')
+  url_prefix = 'https://commondatastorage.googleapis.com/nativeclient-archive2/toolchain'
+  rev = 8002
+  url = "%s/%s/naclsdk_linux_arm-trusted.tgz" % (url_prefix, rev)

[iannucci, 2012/12/07 22:43:39]

nit: These could be globals, since the don't really calculate anything.

[Sam Clegg, 2012/12/07 23:39:19]

Done.

+
+  stamp = os.path.join(sysroot, ".stamp")
+  if os.path.exists(stamp):
+    with open(stamp) as s:
+      if s.read() == url:
+        print "ARM root image already up-to-date: %s" % sysroot
+        return 0
+
+  print "Installing ARM root image: %s" % sysroot
+  if not os.path.isdir(sysroot):
+    os.mkdir(sysroot)
+  tarball = os.path.join(sysroot, 'naclsdk_linux_arm-trusted.tgz')
+  rtn = os.system('curl -L "%s" -o "%s"' % (url, tarball))
+  if rtn:
+    return rtn

[iannucci, 2012/12/07 22:43:39]

Could this make an extra tarball file if curl aborts half way (e.g. timeout)?

I'd use the tempfile module for this.

[Sam Clegg, 2012/12/07 23:39:19]

I'm actually not a fan of too much use of tmpfiles, especially since the tarball
lives inside the sysroot, which now gets cleaned before each download anyway.

+  rtn = os.system('tar xf %s -C %s' % (tarball, sysroot))

[iannucci, 2012/12/07 22:43:39]

Does it make sense to nuke the existing sysroot?

[Sam Clegg, 2012/12/07 23:39:19]

Ooops, yes, thanks.

Done

+  if rtn:
+    return rtn
+  os.remove(tarball)
+  open(stamp, 'w').write(url)

[iannucci, 2012/12/07 22:43:39]

nit: I would explicitly close the file (probably with a with statement)

[Sam Clegg, 2012/12/07 23:39:19]

Done.

+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))