#!/usr/bin/python
# Copyright 2012 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Library for validating ebuild license information, and generating credits.

Documentation on this script is also available here:
  http://www.chromium.org/chromium-os/licensing
"""

import cgi
import codecs
import logging
import os
import re
import tempfile

from chromite.cbuildbot import constants
from chromite.cbuildbot import portage_utilities
from chromite.lib import cros_build_lib
from chromite.lib import osutils

# We are imported by src/repohooks/pre-upload.py in a non chroot environment
# where yaml may not be there, so we don't error on that since it's not needed
# in that case.
try:
  import yaml
except ImportError:
  yaml = None

debug = True

# See http://crbug.com/207004 for discussion.
PER_PKG_LICENSE_DIR = '/var/db/pkg'

STOCK_LICENSE_DIRS = [
    os.path.join(constants.SOURCE_ROOT,
                 'src/third_party/portage-stable/licenses'),
]

# There are licenses for custom software we got and isn't part of
# upstream gentoo.
CUSTOM_LICENSE_DIRS = [
    os.path.join(constants.SOURCE_ROOT,
                 'src/third_party/chromiumos-overlay/licenses'),
]

COPYRIGHT_ATTRIBUTION_DIR = (
    os.path.join(
        constants.SOURCE_ROOT,
        'src/third_party/chromiumos-overlay/licenses/copyright-attribution'))

# Virtual packages don't need to have a license and often don't, so we skip them
# chromeos-base contains google platform packages that are covered by the
# general license at top of tree, so we skip those too.
SKIPPED_CATEGORIES = [
    'virtual',
]

SKIPPED_PACKAGES = [
    # Fix these packages by adding a real license in the code.
    # You should not skip packages just because the license scraping doesn't
    # work. Stick those special cases into PACKAGE_LICENSES.
    # Packages should only be here because they are sub/split packages already
    # covered by the license of the main package.

    # These are Chrome-OS-specific packages, copyright BSD-Google
    'sys-kernel/chromeos-kernel',  # already manually credit Linux
]

SKIPPED_LICENSES = [
    # Some of our packages contain binary blobs for which we have special
    # negotiated licenses, and no need to display anything publicly. Strongly
    # consider using Google-TOS instead, if possible.
    'Proprietary-Binary',

    # If you have an early repo for which license terms have yet to be decided
    # use this. It will cause licensing for the package to be mostly ignored.
    # Official should error for any package with this license.
    'TAINTED', # TODO(dgarrett): Error on official builds with this license.
]

LICENSE_NAMES_REGEX = [
    r'^copyright$',
    r'^copyright[.]txt$',
    r'^copyright[.]regex$',                        # llvm
    r'^copying.*$',
    r'^licen[cs]e.*$',
    r'^licensing.*$',                              # libatomic_ops
    r'^ipa_font_license_agreement_v1[.]0[.]txt$',  # ja-ipafonts
    r'^PKG-INFO$',                                 # copyright assignment for
                                                   # some python packages
                                                   # (netifaces, unittest2)
]

# These are _temporary_ license mappings for packages that do not have a valid
# shared/custom license, or LICENSE file we can use.
# Once this script runs earlier (during the package build process), it will
# block new source without a LICENSE file if the ebuild contains a license
# that requires copyright assignment (BSD and friends).
# At that point, new packages will get fixed to include LICENSE instead of
# adding workaround mappings like those below.
# The way you now fix copyright attribution cases create a custom file with the
# right license directly in COPYRIGHT_ATTRIBUTION_DIR.
PACKAGE_LICENSES = {
    # TODO: replace the naive license parsing code in this script with a hook
    # into portage's license parsing. See http://crbug.com/348779

    # Chrome (the browser) is complicated, it has a morphing license that is
    # either BSD-Google, or BSD-Google,Google-TOS depending on how it was
    # built. We bypass this problem for now by hardcoding the Google-TOS bit as
    # per ChromeOS with non free bits
    'chromeos-base/chromeos-chrome': ['BSD-Google', 'Google-TOS'],

    # Currently the code cannot parse LGPL-3 || ( LGPL-2.1 MPL-1.1 )
    'dev-python/pycairo': ['LGPL-3', 'LGPL-2.1'],
}

# Any license listed list here found in the ebuild will make the code look for
# license files inside the package source code in order to get copyright
# attribution from them.
COPYRIGHT_ATTRIBUTION_LICENSES = [
    'BSD',    # requires distribution of copyright notice
    'BSD-2',  # so does BSD-2 http://opensource.org/licenses/BSD-2-Clause
    'BSD-3',  # and BSD-3? http://opensource.org/licenses/BSD-3-Clause
    'BSD-4',  # and 4?
    'BSD-with-attribution',
    'MIT',
    'MIT-with-advertising',
    'Old-MIT',
]

# The following licenses are not invalid or to show as a less helpful stock
# license, but it's better to look in the source code for a more specific
# license if there is one, but not an error if no better one is found.
# Note that you don't want to set just anything here since any license here
# will be included once in stock form and a second time in custom form if
# found (there is no good way to know that a license we found on disk is the
# better version of the stock version, so we show both).
LOOK_IN_SOURCE_LICENSES = [
    'as-is',  # The stock license is very vague, source always has more details.
    'PSF-2',  # The custom license in python is more complete than the template.

    # As far as I know, we have no requirement to do copyright attribution for
    # these licenses, but the license included in the code has slightly better
    # information than the stock Gentoo one (including copyright attribution).
    'BZIP2',     # Single use license, do copyright attribution.
    'OFL',       # Almost single use license, do copyright attribution.
    'OFL-1.1',   # Almost single use license, do copyright attribution.
    'UoI-NCSA',  # Only used by NSCA, might as well show their custom copyright.
]

# This used to provide overrides. I can't find a valid reason to add any more
# here, though.
PACKAGE_HOMEPAGES = {
    # Example:
    # 'x11-proto/glproto': ['http://www.x.org/'],
}

# These are tokens found in LICENSE= in an ebuild that aren't licenses we
# can actually read from disk.
# You should not use this to blacklist real licenses.
LICENCES_IGNORE = [
    ')',              # Ignore OR tokens from LICENSE="|| ( LGPL-2.1 MPL-1.1 )"
    '(',
    '||',
]

TMPL = 'about_credits.tmpl'
ENTRY_TMPL = 'about_credits_entry.tmpl'
SHARED_LICENSE_TMPL = 'about_credits_shared_license_entry.tmpl'


# This is called directly by src/repohooks/pre-upload.py
def GetLicenseTypesFromEbuild(ebuild_path):
  """Returns a list of license types from the ebuild file.

  This function does not always return the correct list, but it is
  faster than using portageq for not having to access chroot. It is
  intended to be used for tasks such as presubmission checks.

  Args:
    ebuild_path: ebuild to read.

  Returns:
    list of licenses read from ebuild.

  Raises:
    ValueError: ebuild errors.
  """
  ebuild_env_tmpl = """
has() { [[ " ${*:2} " == *" $1 "* ]]; }
inherit() {
  local overlay_list="%(overlay_list)s"
  local eclass overlay f
  for eclass; do
    has ${eclass} ${_INHERITED_} && continue
    _INHERITED_+=" ${eclass}"
    for overlay in %(overlay_list)s; do
      f="${overlay}/eclass/${eclass}.eclass"
      if [[ -e ${f} ]]; then
        source "${f}"
        break
      fi
     done
  done
}
source %(ebuild)s"""

  # TODO: the overlay_list hard-coded here should be changed to look
  # at the current overlay, and then the master overlays. E.g. for an
  # ebuild file in overlay-parrot, we will look at parrot overlay
  # first, and then look at portage-stable and chromiumos, which are
  # listed as masters in overlay-parrot/metadata/layout.conf.
  tmpl_env = {
      'ebuild': ebuild_path,
      'overlay_list': '%s %s' % (
          os.path.join(constants.SOURCE_ROOT,
                       'src/third_party/chromiumos-overlay'),
          os.path.join(constants.SOURCE_ROOT,
                       'src/third_party/portage-stable'))
  }

  with tempfile.NamedTemporaryFile(bufsize=0) as f:
    osutils.WriteFile(f.name, ebuild_env_tmpl % tmpl_env)
    env = osutils.SourceEnvironment(
        f.name, whitelist=['LICENSE'], ifs=' ', multiline=True)

  if not env.get('LICENSE'):
    raise ValueError('No LICENSE found in the ebuild.')
  if re.search(r'[,;]', env['LICENSE']):
    raise ValueError(
        'LICENSE field in the ebuild should be whitespace-limited.')

  return env['LICENSE'].split()


class PackageLicenseError(Exception):
  """Thrown if something fails while getting license information for a package.

  This will cause the processing to error in the end.
  """


class PackageInfo(object):
  """Package info containers, mostly for storing licenses."""

  def __init__(self):

    self.board = None
    self.revision = None

    # Array of scanned license texts.
    self.license_text_scanned = []

    self.category = None
    self.name = None
    self.version = None

    # Looks something like this
    # /mnt/host/source/src/
    #           third_party/portage-stable/net-misc/rsync/rsync-3.0.8.ebuild
    self.ebuild_path = None

    # Array of license names retrieved from ebuild or override in this code.
    self.ebuild_license_names = []
    self.homepages = []
    # This contains licenses names we can read from Gentoo or custom licenses.
    # These are supposed to be shared licenses (i.e. licenses referenced by
    # more then one package), but after all processing, we may find out that
    # some are only used once and they get taken out of the shared pool and
    # pasted directly in the sole package that was using them (see
    # GenerateHTMLLicenseOutput).
    self.license_names = set()

    # We set this if the ebuild has a BSD/MIT like license that requires
    # scanning for a LICENSE file in the source code, or a static mapping
    # in PACKAGE_LICENSES. Not finding one once this is set, is fatal.
    self.need_copyright_attribution = False
    # This flag just says we'd like to include licenses from the source, but
    # not finding any is not fatal.
    self.scan_source_for_licenses = False

    # After reading basic package information, we can mark the package as
    # one to skip in licensing.
    self.skip = False

    # If we failed to get licensing for this package, mark it as such so that
    # it can be flagged when the full license file is being generated.
    self.licensing_failed = False

    # If we are called from a hook, we grab package info from the soure tree.
    # This is also used as a flag to know whether we should do package work
    # based on an installed package, or one that is being built and we got
    # called from the hook.
    self.build_source_tree = None

  @property
  def fullnamerev(self):
    s = '%s-%s' % (self.fullname, self.version)
    if self.revision:
      s += '-r%s' % self.revision
    return s

  @property
  def fullname(self):
    return '%s/%s' % (self.category, self.name)

  @property
  def license_dump_path(self):
    """e.g. /build/x86-alex//var/db/pkg/sys-apps/dtc-1.4.0/license.yaml."""
    return "%s/%s/%s/license.yaml" % (cros_build_lib.GetSysroot(self.board),
                                      PER_PKG_LICENSE_DIR, self.fullnamerev)

  def _BuildInfo(self, filename):
    filename = '%s/build-info/%s' % (self.build_source_tree, filename)
    # Buildinfo properties we read are in US-ASCII, not Unicode.
    try:
      bi = open(filename).read().rstrip()
    # Some properties like HOMEPAGE may be absent.
    except IOError:
      bi = ""
    return bi

  def _RunEbuildPhases(self, phases):
    """Run a list of ebuild phases on an ebuild.

    Args:
      phases: list of phases like ['clean', 'fetch'] or ['unpack'].

    Returns:
      ebuild command output
    """

    return cros_build_lib.RunCommand(
        ['ebuild-%s' % self.board, self.ebuild_path] + phases, print_cmd=debug,
        redirect_stdout=True)

  def _GetOverrideLicense(self):
    """Look in COPYRIGHT_ATTRIBUTION_DIR for license with copyright attribution.

    For dev-util/bsdiff-4.3-r5, the code will look for
    dev-util/bsdiff-4.3-r5
    dev-util/bsdiff-4.3
    dev-util/bsdiff

    It is ok to have more than one bsdiff license file, and an empty file acts
    as a rubout (i.e. an empty dev-util/bsdiff-4.4 will shadow dev-util/bsdiff
    and tell the licensing code to look in the package source for a license
    instead of using dev-util/bsdiff as an override).

    Returns:
      False (no license found) or a multiline license string.
    """
    license_read = None
    # dev-util/bsdiff-4.3-r5 -> bsdiff-4.3-r5
    filename = os.path.basename(self.fullnamerev)
    license_path = os.path.join(COPYRIGHT_ATTRIBUTION_DIR,
                                os.path.dirname(self.fullnamerev))
    pv = portage_utilities.SplitPV(filename)
    pv_no_rev = '%s-%s' % (pv.package, pv.version_no_rev)
    for filename in (pv.pv, pv_no_rev, pv.package):
      file_path = os.path.join(license_path, filename)
      logging.debug("Looking for override copyright attribution license in %s",
                    file_path)
      if os.path.exists(file_path):
        # Turn
        # /../merlin/trunk/src/third_party/chromiumos-overlay/../dev-util/bsdiff
        # into
        # chromiumos-overlay/../dev-util/bsdiff
        short_dir_path = os.path.join(*file_path.rsplit(os.path.sep, 5)[1:])
        license_read = "Copyright Attribution License %s:\n\n" % short_dir_path
        license_read += ReadUnknownEncodedFile(
            file_path, "read copyright attribution license")
        break

    return license_read

  def _ExtractLicenses(self):
    """Scrounge for text licenses in the source of package we'll unpack.

    This is only called if we couldn't get usable licenses from the ebuild,
    or one of them is BSD/MIT like which forces us to look for a file with
    copyright attribution in the source code itself.

    First, we have a shortcut where we scan COPYRIGHT_ATTRIBUTION_DIR to see if
    we find a license for this package. If so, we use that.
    Typically it'll be used if the unpacked source does not have the license
    that we're required to display for copyright attribution (in some cases it's
    plain absent, in other cases, it could be in a filename we don't look for).

    Otherwise, we scan the unpacked source code for what looks like license
    files as defined in LICENSE_NAMES_REGEX.

    Raises:
      AssertionError: on runtime errors
      PackageLicenseError: couldn't find copyright attribution file.
    """
    license_override = self._GetOverrideLicense()
    if license_override:
      self.license_text_scanned = [license_override]
      return

    if self.build_source_tree:
      workdir = "%s/work" % self.build_source_tree
    else:
      self._RunEbuildPhases(['clean', 'fetch'])
      output = self._RunEbuildPhases(['unpack']).output.splitlines()
      # Output is spammy, it looks like this:
      #  * gc-7.2d.tar.gz RMD160 SHA1 SHA256 size ;-) ...                 [ ok ]
      #  * checking gc-7.2d.tar.gz ;-) ...                                [ ok ]
      #  * Running stacked hooks for pre_pkg_setup
      #  *    sysroot_build_bin_dir ...
      #  [ ok ]
      #  * Running stacked hooks for pre_src_unpack
      #  *    python_multilib_setup ...
      #  [ ok ]
      # >>> Unpacking source...
      # >>> Unpacking gc-7.2d.tar.gz to /build/x86-alex/tmp/po/[...]ps-7.2d/work
      # >>> Source unpacked in /build/x86-alex/tmp/portage/[...]ops-7.2d/work
      # So we only keep the last 2 lines, the others we don't care about.
      output = [line for line in output if line[0:3] == ">>>" and
                line != ">>> Unpacking source..."]
      for line in output:
        logging.info(line)

      args = ['portageq-%s' % self.board, 'envvar', 'PORTAGE_TMPDIR']
      result = cros_build_lib.RunCommand(args, print_cmd=debug,
                                         redirect_stdout=True)
      tmpdir = result.output.splitlines()[0]
      # tmpdir gets something like /build/daisy/tmp/
      workdir = os.path.join(tmpdir, 'portage', self.fullnamerev, 'work')

      if not os.path.exists(workdir):
        raise AssertionError("Unpack of %s didn't create %s. Version mismatch" %
                             (self.fullnamerev, workdir))

    # You may wonder how deep should we go?
    # In case of packages with sub-packages, it could be deep.
    # Let's just be safe and get everything we can find.
    # In the case of libatomic_ops, it's actually required to look deep
    # to find the MIT license:
    # dev-libs/libatomic_ops-7.2d/work/gc-7.2/libatomic_ops/doc/LICENSING.txt
    args = ['find', workdir, '-type', 'f']
    result = cros_build_lib.RunCommand(args, print_cmd=debug,
                                       redirect_stdout=True).output.splitlines()
    # Truncate results to look like this: swig-2.0.4/COPYRIGHT
    files = [x[len(workdir):].lstrip('/') for x in result]
    license_files = []
    for name in files:
      # When we scan a source tree managed by git, this can contain license
      # files that are not part of the source. Exclude those.
      # (e.g. .git/refs/heads/licensing)
      if ".git/" in name:
        continue
      basename = os.path.basename(name)
      # Looking for license.* brings up things like license.gpl, and we
      # never want a GPL license when looking for copyright attribution,
      # so we skip them here. We also skip regexes that can return
      # license.py (seen in some code).
      if re.search(r".*GPL.*", basename) or re.search(r"\.py$", basename):
        continue
      for regex in LICENSE_NAMES_REGEX:
        if re.search(regex, basename, re.IGNORECASE):
          license_files.append(name)
          break

    if not license_files:
      if self.need_copyright_attribution:
        logging.error("""
%s: unable to find usable license.
Typically this will happen because the ebuild says it's MIT or BSD, but there
was no license file that this script could find to include along with a
copyright attribution (required for BSD/MIT).

If this is Google source, please change
LICENSE="BSD"
to
LICENSE="BSD-Google"

If not, go investigate the unpacked source in %s,
and find which license to assign.  Once you found it, you should copy that
license to a file under %s
(or you can modify LICENSE_NAMES_REGEX to pickup a license file that isn't
being scraped currently).""",
                      self.fullnamerev, workdir, COPYRIGHT_ATTRIBUTION_DIR)
        raise PackageLicenseError()
      else:
        # We can get called for a license like as-is where it's preferable
        # to find a better one in the source, but not fatal if we didn't.
        logging.info("Was not able to find a better license for %s "
                     "in %s to replace the more generic one from ebuild",
                     self.fullnamerev, workdir)

    # Examples of multiple license matches:
    # dev-lang/swig-2.0.4-r1: swig-2.0.4/COPYRIGHT swig-2.0.4/LICENSE
    # dev-libs/glib-2.32.4-r1: glib-2.32.4/COPYING pkg-config-0.26/COPYING
    # dev-libs/libnl-3.2.14: libnl-doc-3.2.14/COPYING libnl-3.2.14/COPYING
    # dev-libs/libpcre-8.30-r2: pcre-8.30/LICENCE pcre-8.30/COPYING
    # dev-libs/libusb-0.1.12-r6: libusb-0.1.12/COPYING libusb-0.1.12/LICENSE
    # dev-libs/pyzy-0.1.0-r1: db/COPYING pyzy-0.1.0/COPYING
    # net-misc/strongswan-5.0.2-r4: strongswan-5.0.2/COPYING
    #                               strongswan-5.0.2/LICENSE
    # sys-process/procps-3.2.8_p11: debian/copyright procps-3.2.8/COPYING
    logging.info('License(s) for %s: %s', self.fullnamerev,
                 ' '.join(license_files))
    for license_file in sorted(license_files):
      # Joy and pink ponies. Some license_files are encoded as latin1 while
      # others are utf-8 and of course you can't know but only guess.
      license_path = os.path.join(workdir, license_file)
      license_txt = ReadUnknownEncodedFile(license_path, "Adding License")

      self.license_text_scanned += [
          "Scanned Source License %s:\n\n%s" % (license_file, license_txt)]

    # We used to clean up here, but there have been many instances where
    # looking at unpacked source to see where the licenses were, was useful
    # so let's disable this for now
    # self._RunEbuildPhases(['clean'])

  def GetPackageInfo(self, fullnamewithrev):
    """Populate PackageInfo with package license, and homepage.

    self.ebuild_license_names will not be filled if the package is skipped
    or if there was an issue getting data from the ebuild.
    self.license_names will only get the licenses that we can paste
    as shared licenses.
    scan_source_for_licenses will be set if we should unpack the source to look
    for licenses
    if need_copyright_attribution is also set, not finding a license in the
    source is fatal (PackageLicenseError will get raised).

    Args:
      fullnamewithrev: e.g. dev-libs/libatomic_ops-7.2d

    Raises:
      AssertionError: on runtime errors
    """
    if not fullnamewithrev:
      if not self.build_source_tree:
        raise AssertionError("Cannot continue without full name or source tree")
      fullnamewithrev = "%s/%s" % (self._BuildInfo("CATEGORY"),
                                   self._BuildInfo("PF"))
      logging.debug("Computed package name %s from %s", fullnamewithrev,
                    self.build_source_tree)

    try:
      cpv = portage_utilities.SplitCPV(fullnamewithrev)
      # A bad package can either raise a TypeError exception or return None,
      # so we catch both cases.
      if not cpv:
        raise TypeError
    except TypeError:
      raise AssertionError("portage couldn't find %s, missing version number?" %
                           fullnamewithrev)

    self.category, self.name, self.version, self.revision = (
        cpv.category, cpv.package, cpv.version_no_rev, cpv.rev)

    if self.revision is not None:
      self.revision = str(self.revision).lstrip('r')
      if self.revision == '0':
        self.revision = None

    if self.category in SKIPPED_CATEGORIES:
      logging.info("%s in SKIPPED_CATEGORIES, skip package", self.fullname)
      self.skip = True
      return

    if self.fullname in SKIPPED_PACKAGES:
      logging.info("%s in SKIPPED_PACKAGES, skip package", self.fullname)
      self.skip = True
      return

  def _FindEbuildPath(self):
    """Populate package info from an ebuild retrieved via equery."""
    # By default, equery returns the latest version of the package. A
    # build may have used an older version than what is currently
    # available in the source tree (a build dependency can be pinned
    # to an older version of a package for compatibility
    # reasons). Therefore we need to tell equery that we want the
    # exact version number used in the image build as opposed to the
    # latest available in the source tree.
    args = ['equery-%s' % self.board, '-q', '-C', 'which', self.fullnamerev]
    try:
      path = cros_build_lib.RunCommand(args, print_cmd=True,
                                       redirect_stdout=True).output.strip()
      if not path:
        raise AssertionError
    except:
      raise AssertionError('GetEbuildPath for %s failed.\n'
                           'Is your tree clean? Delete %s and rebuild' %
                           (self.name,
                            cros_build_lib.GetSysroot(board=self.board)))
    logging.debug("%s -> %s", " ".join(args), path)

    if not os.access(path, os.F_OK):
      raise AssertionError("Can't access %s", path)

    self.ebuild_path = path

  def _ReadEbuildMetadata(self):
    """Read package metadata retrieved via portageq."""
    args = ['portageq-%s' % self.board, 'metadata',
            cros_build_lib.GetSysroot(board=self.board), 'ebuild',
            self.fullnamerev, 'HOMEPAGE', 'LICENSE']
    tmp = cros_build_lib.RunCommand(args, print_cmd=debug,
                                    redirect_stdout=True)
    lines = tmp.output.splitlines()
    # Runs:
    # portageq metadata /build/x86-alex ebuild net-misc/wget-1.12-r2 \
    #                                             HOMEPAGE LICENSE
    # Returns:
    # http://www.gnu.org/software/wget/
    # GPL-3
    self.homepages, self.ebuild_license_names = (
        lines[0].split(), lines[1].split())

  def _TestEbuildContents(self):
    """Discover if the ebuild installed any files.

    Returns:
      bool which tells if any files were installed.
    """
    # Search for anything the ebuild might install, other than a directory.
    args = ['equery-%s' % self.board, '-q', '-C', 'files', self.fullnamerev,
            '-f', 'obj']
    tmp = cros_build_lib.RunCommand(args, print_cmd=debug, redirect_stdout=True)
    lines = tmp.output.splitlines()

    # lines is an array of the file names installed by the ebuild.
    return bool(lines)

  def GetLicenses(self):
    """Get licenses from the ebuild field and the unpacked source code.

    Some packages have static license mappings applied to them that get
    retrieved from the ebuild.

    For others, we figure out whether the package source should be scanned to
    add licenses found there.

    Raises:
      AssertionError: on runtime errors
      PackageLicenseError: couldn't find license in ebuild and source.
    """
    if self.build_source_tree:
      # If the total size installed is zero, we installed no content to license.
      if self._BuildInfo("SIZE").strip() == '0':
        self.skip = True
        return
      self.homepages = self._BuildInfo("HOMEPAGE").split()
      self.ebuild_license_names = self._BuildInfo("LICENSE").split()
    else:
      self._FindEbuildPath()
      self._ReadEbuildMetadata()
      self.skip = self.skip or not self._TestEbuildContents()

    # If this ebuild only uses skipped licenses, skip it.
    if (self.ebuild_license_names and
        all(l in SKIPPED_LICENSES for l in self.ebuild_license_names)):
      self.skip = True

    if self.skip:
      return

    if self.fullname in PACKAGE_HOMEPAGES:
      self.homepages = PACKAGE_HOMEPAGES[self.fullname]

    # Packages with missing licenses or licenses that need mapping (like
    # BSD/MIT) are hardcoded here:
    if self.fullname in PACKAGE_LICENSES:
      self.ebuild_license_names = PACKAGE_LICENSES[self.fullname]
      logging.info("Static license mapping for %s: %s", self.fullnamerev,
                   ",".join(self.ebuild_license_names))
    else:
      logging.info("Read licenses for %s: %s", self.fullnamerev,
                   ",".join(self.ebuild_license_names))

    # Lots of packages in chromeos-base have their license set to BSD instead
    # of BSD-Google:
    new_license_names = []
    for license_name in self.ebuild_license_names:
      # TODO: temp workaround for http;//crbug.com/348750 , remove when the bug
      # is fixed.
      if (license_name == "BSD" and
          self.fullnamerev.startswith("chromeos-base/")):
        license_name = "BSD-Google"
        logging.error(
            "Fixed BSD->BSD-Google for %s because it's in chromeos-base. "
            "Please fix the LICENSE field in the ebuild", self.fullnamerev)
      # TODO: temp workaround for http;//crbug.com/348749 , remove when the bug
      # is fixed.
      if license_name == "Proprietary":
        license_name = "Google-TOS"
        logging.error(
            "Fixed Proprietary -> Google-TOS for %s. "
            "Please fix the LICENSE field in the ebuild", self.fullnamerev)
      new_license_names.append(license_name)
    self.ebuild_license_names = new_license_names

    # The ebuild license field can look like:
    # LICENSE="GPL-3 LGPL-3 Apache-2.0" (this means AND, as in all 3)
    # for third_party/portage-stable/app-admin/rsyslog/rsyslog-5.8.11.ebuild
    # LICENSE="|| ( LGPL-2.1 MPL-1.1 )"
    # for third_party/portage-stable/x11-libs/cairo/cairo-1.8.8.ebuild

    # The parser isn't very smart and only has basic support for the
    # || ( X Y ) OR logic to do the following:
    # In order to save time needlessly unpacking packages and looking or a
    # cleartext license (which is really a crapshoot), if we have a license
    # like BSD that requires looking for copyright attribution, but we can
    # chose another license like GPL, we do that.

    if not self.skip and not self.ebuild_license_names:
      logging.error("%s: no license found in ebuild. FIXME!", self.fullnamerev)
      # In a bind, you could comment this out. I'm making the output fail to
      # get your attention since this error really should be fixed, but if you
      # comment out the next line, the script will try to find a license inside
      # the source.
      raise PackageLicenseError()

    # This is not invalid, but the parser can't deal with it, so if it ever
    # happens, error out to tell the programmer to do something.
    # dev-python/pycairo-1.10.0-r4: LGPL-3 || ( LGPL-2.1 MPL-1.1 )
    if "||" in self.ebuild_license_names[1:]:
      logging.error("%s: Can't parse || in the middle of a license: %s",
                    self.fullnamerev, ' '.join(self.ebuild_license_names))
      raise PackageLicenseError()

    or_licenses_and_one_is_no_attribution = False
    # We do a quick early pass first so that the longer pass below can
    # run accordingly.
    for license_name in [x for x in self.ebuild_license_names
                         if x not in LICENCES_IGNORE]:
      # Here we have an OR case, and one license that we can use stock, so
      # we remember that in order to be able to skip license attributions if
      # any were in the OR.
      if (self.ebuild_license_names[0] == "||" and
          license_name not in COPYRIGHT_ATTRIBUTION_LICENSES):
        or_licenses_and_one_is_no_attribution = True

    for license_name in [x for x in self.ebuild_license_names
                         if x not in LICENCES_IGNORE]:
      # Licenses like BSD or MIT can't be used as is because they do not contain
      # copyright self. They have to be replaced by copyright file given in the
      # source code, or manually mapped by us in PACKAGE_LICENSES
      if license_name in COPYRIGHT_ATTRIBUTION_LICENSES:
        # To limit needless efforts, if a package is BSD or GPL, we ignore BSD
        # and use GPL to avoid scanning the package, but we can only do this if
        # or_licenses_and_one_is_no_attribution has been set above.
        # This ensures that if we have License: || (BSD3 BSD4), we will
        # look in the source.
        if or_licenses_and_one_is_no_attribution:
          logging.info("%s: ignore license %s because ebuild LICENSES had %s",
                       self.fullnamerev, license_name,
                       ' '.join(self.ebuild_license_names))
        else:
          logging.info("%s: can't use %s, will scan source code for copyright",
                       self.fullnamerev, license_name)
          self.need_copyright_attribution = True
          self.scan_source_for_licenses = True
      else:
        self.license_names.add(license_name)
        # We can't display just 2+ because it only contains text that says to
        # read v2 or v3.
        if license_name == 'GPL-2+':
          self.license_names.add('GPL-2')
        if license_name == 'LGPL-2+':
          self.license_names.add('LGPL-2')

      if license_name in LOOK_IN_SOURCE_LICENSES:
        logging.info("%s: Got %s, will try to find better license in source...",
                     self.fullnamerev, license_name)
        self.scan_source_for_licenses = True

    if self.license_names:
      logging.info('%s: using stock|cust license(s) %s',
                   self.fullnamerev, ','.join(self.license_names))

    # If the license(s) could not be found, or one requires copyright
    # attribution, dig in the source code for license files:
    # For instance:
    # Read licenses from ebuild for net-dialup/ppp-2.4.5-r3: BSD,GPL-2
    # We need get the substitution file for BSD and add it to GPL.
    if self.scan_source_for_licenses:
      self._ExtractLicenses()

    # This shouldn't run, but leaving as sanity check.
    if not self.license_names and not self.license_text_scanned:
      raise AssertionError("Didn't find usable licenses for %s" %
                           self.fullnamerev)


class Licensing(object):
  """Do the actual work of extracting licensing info and outputting html."""

  def __init__(self, board, package_fullnames, gen_licenses):
    # eg x86-alex
    self.board = board
    # List of stock and custom licenses referenced in ebuilds. Used to
    # print a report. Dict value says which packages use that license.
    self.licenses = {}

    # Licenses are supposed to be generated at package build time and be
    # ready for us, but in case they're not, they can be generated.
    self.gen_licenses = gen_licenses

    # This keeps track of whether we have an incomplete license file due to
    # package errors during parsing.
    # Any non empty list at the end shows the list of packages that caused
    # errors.
    self.incomplete_packages = []

    self.package_text = {}
    self.entry_template = None

    # We need to have a dict for the list of packages objects, index by package
    # fullnamerev, so that when we scan our licenses at the end, and find out
    # some shared licenses are only used by one package, we can access that
    # package object by name, and add the license directly in that object.
    self.packages = {}
    self._package_fullnames = package_fullnames

  @property
  def sorted_licenses(self):
    return sorted(self.licenses.keys(), key=str.lower)

  def _SaveLicenseDump(self, pkg):
    if pkg.build_source_tree:
      save_file = "%s/build-info/license.yaml" % pkg.build_source_tree
    else:
      save_file = pkg.license_dump_path
    logging.debug("Saving license to %s", save_file)
    save_dir = os.path.dirname(save_file)
    if not os.path.isdir(save_dir):
      os.makedirs(save_dir, 0755)
    with open(save_file, "w") as f:
      yaml_dump = []
      for key, value in pkg.__dict__.items():
        yaml_dump.append([key, value])
      f.write(yaml.dump(yaml_dump))

  def _LoadLicenseDump(self, pkg):
    save_file = pkg.license_dump_path
    logging.debug("Getting license from %s for %s", save_file, pkg.name)
    with open(save_file, "r") as f:
      # yaml.safe_load barfs on unicode it output, but we don't really need it.
      yaml_dump = yaml.load(f)
      for key, value in yaml_dump:
        pkg.__dict__[key] = value

  def LicensedPackages(self, license_name):
    """Return list of packages using a given license."""
    return self.licenses[license_name]

  def LoadPackageInfo(self, board):
    """Populate basic package info for all packages from their ebuild."""
    for package_name in self._package_fullnames:
      pkg = PackageInfo()
      pkg.board = board
      pkg.GetPackageInfo(package_name)
      self.packages[package_name] = pkg

  def HookPackageProcess(self, pkg_build_path):
    """Different entry point to populate a packageinfo.

    This is called instead of LoadPackageInfo when called by a package build.

    Args:
      pkg_build_path: unpacked being built by emerge.
    """
    pkg = PackageInfo()
    pkg.build_source_tree = pkg_build_path
    pkg.GetPackageInfo(None)
    if not pkg.skip:
      pkg.GetLicenses()
    self._SaveLicenseDump(pkg)

  def ProcessPackageLicenses(self):
    """Iterate through all packages provided and gather their licenses.

    GetLicenses will scrape licenses from the code and/or gather stock license
    names. We gather the list of stock and custom ones for later processing.

    Do not call this after adding virtual packages with AddExtraPkg.
    """
    for package_name in self.packages:
      pkg = self.packages[package_name]
      if pkg.skip:
        if self.gen_licenses:
          logging.info("Package %s is in skip list", package_name)
        else:
          # If we do a licensing run expecting to get licensing objects from
          # an image build, virtual packages will be missing such objects
          # because virtual packages do not get the install hook run at build
          # time. Because this script may not have permissions to write in the
          # /var/db/ directory, we don't want it to generate useless license
          # bits for virtual packages. As a result, ignore virtual packages
          # here.
          if pkg.category == "virtual":
            logging.debug("Ignoring %s virtual package", package_name)
            continue

      # Other skipped packages get dumped with incomplete info and the skip flag
      if not os.path.exists(pkg.license_dump_path) and not self.gen_licenses:
        logging.warning(">>> License for %s is missing, creating now <<<",
                        package_name)
      if not os.path.exists(pkg.license_dump_path) or self.gen_licenses:
        if not pkg.skip:
          try:
            pkg.GetLicenses()
          except PackageLicenseError:
            pkg.licensing_failed = True
        # We dump packages where licensing failed too.
        self._SaveLicenseDump(pkg)

    # To debug the code, we force the data to be re-read from the dumps
    # instead of reusing what we may have in memory.
    for package_name in self.packages:
      pkg = self.packages[package_name]
      if pkg.category == "virtual":
        continue

      self._LoadLicenseDump(pkg)
      logging.debug("loaded dump for %s", pkg.fullnamerev)
      if pkg.skip:
        logging.info("Package %s is in skip list", pkg.fullnamerev)
      if pkg.licensing_failed:
        logging.info("Package %s failed licensing", pkg.fullnamerev)
        self.incomplete_packages += [pkg.fullnamerev]

  def AddExtraPkg(self, pkg_data):
    """Allow adding pre-created virtual packages.

    GetLicenses will not work on them, so add them after having run
    ProcessPackages.

    Args:
      pkg_data: array of package data as defined below
    """
    pkg = PackageInfo()
    pkg.board = self.board
    pkg.category = pkg_data[0]
    pkg.name = pkg_data[1]
    pkg.version = pkg_data[2]
    pkg.homepages = pkg_data[3]      # this is a list
    pkg.license_names = pkg_data[4]  # this is also a list
    pkg.ebuild_license_names = pkg_data[4]
    self.packages[pkg.fullnamerev] = pkg

  # Called directly by src/repohooks/pre-upload.py
  @staticmethod
  def FindLicenseType(license_name):
    """Says if a license is stock Gentoo, custom, or doesn't exist."""

    for directory in STOCK_LICENSE_DIRS:
      path = '%s/%s' % (directory, license_name)
      if os.path.exists(path):
        return "Gentoo Package Stock"

    for directory in CUSTOM_LICENSE_DIRS:
      path = '%s/%s' % (directory, license_name)
      if os.path.exists(path):
        return "Custom"

    if license_name in SKIPPED_LICENSES:
      return "Custom"

    raise AssertionError("""
license %s could not be found in %s
If the license in the ebuild is correct,
a) a stock license should be added to portage-stable/licenses :
running `cros_portage_upgrade` inside of the chroot should clone this repo
to /tmp/portage/:
https://chromium.googlesource.com/chromiumos/overlays/portage/+/gentoo
find the new licenses under licenses, and add them to portage-stable/licenses

b) if it's a non gentoo package with a custom license, you can copy that license
to third_party/chromiumos-overlay/licenses/

Try re-running the script with -p cat/package-ver --generate
after fixing the license.""" %
                         (license_name,
                          '\n'.join(STOCK_LICENSE_DIRS + CUSTOM_LICENSE_DIRS))
                        )

  @staticmethod
  def ReadSharedLicense(license_name):
    """Read and return stock or cust license file specified in an ebuild."""

    license_path = None
    for directory in STOCK_LICENSE_DIRS + CUSTOM_LICENSE_DIRS:
      path = os.path.join(directory, license_name)
      if os.path.exists(path):
        license_path = path
        break

    if license_path:
      return ReadUnknownEncodedFile(license_path, "read license")
    else:
      raise AssertionError("license %s could not be found in %s"
                           % (license_name,
                              '\n'.join(STOCK_LICENSE_DIRS +
                                        CUSTOM_LICENSE_DIRS))
                          )

  @staticmethod
  def EvaluateTemplate(template, env):
    """Expand a template with vars like {{foo}} using a dict of expansions."""
    # TODO switch to stock python templates.
    for key, val in env.iteritems():
      template = template.replace('{{%s}}' % key, val)
    return template

  def _GeneratePackageLicenseText(self, pkg):
    """Concatenate all licenses related to a pkg.

    This means a combination of ebuild shared licenses and licenses read from
    the pkg source tree, if any.

    Args:
      pkg: PackageInfo object

    Raises:
      AssertionError: on runtime errors
    """
    license_text = []
    for license_text_scanned in pkg.license_text_scanned:
      license_text.append(license_text_scanned)
      license_text.append('%s\n' % ('-=' * 40))

    license_pointers = []
    # sln: shared license name.
    for sln in pkg.license_names:
      # Says whether it's a stock gentoo or custom license.
      license_type = self.FindLicenseType(sln)
      license_pointers.append(
          "<li><a href='#%s'>%s License %s</a></li>" % (
              sln, license_type, sln))

    # This should get caught earlier, but one extra check.
    if not license_text + license_pointers:
      raise AssertionError('Ended up with no license_text for %s', pkg.name)

    env = {
        'name': "%s-%s" % (pkg.name, pkg.version),
        'url': cgi.escape(pkg.homepages[0]) if pkg.homepages else '',
        'licenses_txt': cgi.escape('\n'.join(license_text)) or '',
        'licenses_ptr': '\n'.join(license_pointers) or '',
    }
    self.package_text[pkg] = self.EvaluateTemplate(self.entry_template, env)

  def GenerateHTMLLicenseOutput(self, output_file,
                                output_template=TMPL,
                                entry_template=ENTRY_TMPL,
                                license_template=SHARED_LICENSE_TMPL):
    """Generate the combined html license file used in ChromeOS.

    Args:
      output_file: resulting HTML license output.
      output_template: template for the entire HTML file.
      entry_template: template for per package entries.
      license_template: template for shared license entries.
    """
    self.entry_template = ReadUnknownEncodedFile(entry_template)
    sorted_license_txt = []

    # Keep track of which licenses are used by which packages.
    for pkg in self.packages.values():
      if pkg.skip or pkg.licensing_failed:
        continue
      for sln in pkg.license_names:
        self.licenses.setdefault(sln, []).append(pkg.fullnamerev)

    # Find licenses only used once, and roll them in the package that uses them.
    # We use keys() because licenses is modified in the loop, so we can't use
    # an iterator.
    for sln in self.licenses.keys():
      if len(self.licenses[sln]) == 1:
        pkg_fullnamerev = self.licenses[sln][0]
        logging.info("Collapsing shared license %s into single use license "
                     "(only used by %s)", sln, pkg_fullnamerev)
        license_type = self.FindLicenseType(sln)
        license_txt = self.ReadSharedLicense(sln)
        single_license = "%s License %s:\n\n%s" % (license_type, sln,
                                                   license_txt)
        pkg = self.packages[pkg_fullnamerev]
        pkg.license_text_scanned.append(single_license)
        pkg.license_names.remove(sln)
        del self.licenses[sln]

    for pkg in sorted(self.packages.values(),
                      key=lambda x: (x.name.lower(), x.version, x.revision)):
      if pkg.skip:
        logging.debug("Skipping package %s", pkg.fullnamerev)
        continue
      if pkg.licensing_failed:
        logging.debug("Package %s failed licensing, skipping", pkg.fullnamerev)
        continue
      self._GeneratePackageLicenseText(pkg)
      sorted_license_txt += [self.package_text[pkg]]

    # Now generate the bottom of the page that will contain all the shared
    # licenses and a list of who is pointing to them.
    license_template = ReadUnknownEncodedFile(license_template)

    licenses_txt = []
    for license_name in self.sorted_licenses:
      env = {
          'license_name': license_name,
          'license': cgi.escape(self.ReadSharedLicense(license_name)),
          'license_type': self.FindLicenseType(license_name),
          'license_packages': ' '.join(self.LicensedPackages(license_name)),
      }
      licenses_txt += [self.EvaluateTemplate(license_template, env)]

    file_template = ReadUnknownEncodedFile(output_template)
    env = {
        'entries': '\n'.join(sorted_license_txt),
        'licenses': '\n'.join(licenses_txt),
    }
    osutils.WriteFile(output_file,
                      self.EvaluateTemplate(file_template, env).encode('UTF-8'))


def ListInstalledPackages(board, all_packages=False):
  """Return a list of all packages installed for a particular board."""

  # If all_packages is set to True, all packages visible in the build
  # chroot are used to generate the licensing file. This is not what you want
  # for a release license file, but it's a way to run licensing checks against
  # all packages.
  # If it's set to False, it will only generate a licensing file that contains
  # packages used for a release build (as determined by the dependencies for
  # virtual/target-os).

  if all_packages:
    # The following returns all packages that were part of the build tree
    # (many get built or used during the build, but do not get shipped).
    # Note that it also contains packages that are in the build as
    # defined by build_packages but not part of the image we ship.
    args = ["equery-%s" % board, "list", "*"]
    packages = cros_build_lib.RunCommand(args, print_cmd=debug,
                                         redirect_stdout=True
                                        ).output.splitlines()
  else:
    # The following returns all packages that were part of the build tree
    # (many get built or used during the build, but do not get shipped).
    # Note that it also contains packages that are in the build as
    # defined by build_packages but not part of the image we ship.
    args = ["emerge-%s" % board, "--with-bdeps=y", "--usepkgonly",
            "--emptytree", "--pretend", "--color=n", "virtual/target-os"]
    emerge = cros_build_lib.RunCommand(args, print_cmd=debug,
                                       redirect_stdout=True).output.splitlines()
    # Another option which we've decided not to use, is bdeps=n.  This outputs
    # just the packages we ship, but does not packages that were used to build
    # them, including a package like flex which generates a .a that is included
    # and shipped in ChromeOS.
    # We've decided to credit build packages, even if we're not legally required
    # to (it's always nice to do), and that way we get corner case packages like
    # flex. This is why we use bdep=y and not bdep=n.

    packages = []
    # [binary   R    ] x11-libs/libva-1.1.1 to /build/x86-alex/
    pkg_rgx = re.compile(r'\[[^]]+R[^]]+\] (.+) to /build/.*')
    # If we match something else without the 'R' like
    # [binary     U  ] chromeos-base/pepper-flash-13.0.0.133-r1 [12.0.0.77-r1]
    # this is bad and we should die on this.
    pkg_rgx2 = re.compile(r'(\[[^]]+\] .+) to /build/.*')
    for line in emerge:
      match = pkg_rgx.search(line)
      match2 = pkg_rgx2.search(line)
      if match:
        packages.append(match.group(1))
      elif match2:
        raise AssertionError("Package incorrectly installed, try eclean-%s" %
                             board, "\n%s" % match2.group(1))

  return packages


def _HandleIllegalXMLChars(text):
  """Handles illegal XML Characters.

  XML 1.0 acceptable character range:
  Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | \
           [#x10000-#x10FFFF]

  This function finds all illegal characters in the text and filters
  out all whitelisted characters (e.g. ^L).

  Args:
    text: text to examine.

  Returns:
    Filtered |text| and a list of non-whitelisted illegal characters found.
  """
  whitelist_re = re.compile(u'[\x0c]')
  text = whitelist_re.sub('', text)
  # illegal_chars_re includes all illegal characters (whitelisted or
  # not), so we can expand the whitelist without modifying this line.
  illegal_chars_re = re.compile(
      u'[\x00-\x08\x0b\x0c\x0e-\x1F\uD800-\uDFFF\uFFFE\uFFFF]')
  return (text, illegal_chars_re.findall(text))


def ReadUnknownEncodedFile(file_path, logging_text=None):
  """Read a file of unknown encoding (UTF-8 or latin) by trying in sequence.

  Args:
    file_path: what to read.
    logging_text: what to display for logging depending on file read.

  Returns:
    File content, possibly converted from latin1 to UTF-8.

  Raises:
    Assertion error: if non-whitelisted illegal XML characters
      are found in the file.
    ValueError: returned if we get invalid XML.
  """
  try:
    with codecs.open(file_path, encoding="utf-8") as c:
      file_txt = c.read()
      if logging_text:
        logging.info("%s %s (UTF-8)", logging_text, file_path)
  except UnicodeDecodeError:
    with codecs.open(file_path, encoding="latin1") as c:
      file_txt = c.read()
      if logging_text:
        logging.info("%s %s (latin1)", logging_text, file_path)

  file_txt, char_list = _HandleIllegalXMLChars(file_txt)

  if char_list:
    raise ValueError('Illegal XML characters %s found in %s.' %
                     (char_list, file_path))

  return file_txt