Support optional prop assignments

This CL adds a number of changes to make the assignment of system
properties to be less confusing.

1. Added `a ?= b` syntax, which is called optional prop assignments. The
prop `a` gets the value `b` only when there is no non-optional prop
assignment for `a` such as `a = c`. This is useful for props that
provide some reasonable default values as fallback.

2. With the introduction of the optional prop assignment syntax,
duplicated non-optional assignments is prohibited; e.g., the follwing
now triggers a build-time error:

a = b
a = c

, but the following doesn't:

a ?= b
a = c

Note that the textual order between the optional and non-optional
assignments doesn't matter. The non-optional assignment eclipses the
optional assignment even when the former appears 'before' the latter.

a = c
a ?= b

In the above, `a` gets the value `c`

When there are multiple optional assignments without a non-optional
assignments as shown below, the last one wins:

a ?= b
a ?= c

`a` becomes `c`. Specifically, the former assignment is commented out
and the latter is converted to a non-optional assignment.

3. post_process_props.py is modified so that when a prop assignment is
deleted, changed, or added, the changes are recorded as comments. This
is to aid debugging. Previously, it was often difficult to find out why
a certain sysprop assignment is missing or is added.

4. post_process_prop.py now has a unittest

Bug: 117892318
Bug: 158735147
Test: atest --host post_process_prop_unittest

Exempt-From-Owner-Approval: cherry-pick from master

Merged-In: I9c073a21c8257987cf2378012cadaeeeb698a4fb
(cherry picked from commit 7aeb8de74e)
Change-Id: I9c073a21c8257987cf2378012cadaeeeb698a4fb
This commit is contained in:
Jiyong Park 2020-06-22 17:30:57 +09:00
parent 4d1284c0b7
commit d721e870bc
5 changed files with 369 additions and 31 deletions

View File

@ -71,10 +71,11 @@ endef
define build-properties
ALL_DEFAULT_INSTALLED_MODULES += $(2)
# TODO(b/117892318): eliminate the call to uniq-pairs-by-first-component when
# it is guaranteed that there is no dup.
$(eval # Properties can be assigned using `prop ?= value` or `prop = value` syntax.)
$(eval # Eliminate spaces around the ?= and = separators.)
$(foreach name,$(strip $(4)),\
$(eval _resolved_$(name) := $$(call collapse-pairs, $$(call uniq-pairs-by-first-component,$$($(name)),=)))\
$(eval _temp := $$(call collapse-pairs,$$($(name)),?=))\
$(eval _resolved_$(name) := $$(call collapse-pairs,$$(_temp),=))\
)
$(2): $(POST_PROCESS_PROPS) $(INTERNAL_BUILD_ID_MAKEFILE) $(API_FINGERPRINT) $(3)

View File

@ -37,3 +37,22 @@ python_binary_host {
},
},
}
python_test_host {
name: "post_process_props_unittest",
main: "test_post_process_props.py",
srcs: [
"post_process_props.py",
"test_post_process_props.py",
],
version: {
py2: {
enabled: false,
},
py3: {
enabled: true,
},
},
test_config: "post_process_props_unittest.xml",
test_suites: ["general-tests"],
}

View File

@ -16,8 +16,8 @@
import sys
# Usage: post_process_props.py file.prop [blacklist_key, ...]
# Blacklisted keys are removed from the property file, if present
# Usage: post_process_props.py file.prop [disallowed_key, ...]
# Disallowed keys are removed from the property file, if present
# See PROP_VALUE_MAX in system_properties.h.
# The constant in system_properties.h includes the terminating NUL,
@ -29,8 +29,8 @@ PROP_VALUE_MAX = 91
def mangle_build_prop(prop_list):
# If ro.debuggable is 1, then enable adb on USB by default
# (this is for userdebug builds)
if prop_list.get("ro.debuggable") == "1":
val = prop_list.get("persist.sys.usb.config")
if prop_list.get_value("ro.debuggable") == "1":
val = prop_list.get_value("persist.sys.usb.config")
if "adb" not in val:
if val == "":
val = "adb"
@ -40,52 +40,121 @@ def mangle_build_prop(prop_list):
# UsbDeviceManager expects a value here. If it doesn't get it, it will
# default to "adb". That might not the right policy there, but it's better
# to be explicit.
if not prop_list.get("persist.sys.usb.config"):
if not prop_list.get_value("persist.sys.usb.config"):
prop_list.put("persist.sys.usb.config", "none");
def validate(prop_list):
"""Validate the properties.
If the value of a sysprop exceeds the max limit (91), it's an error, unless
the sysprop is a read-only one.
Checks if there is no optional prop assignments.
Returns:
True if nothing is wrong.
"""
check_pass = True
for p in prop_list.get_all():
for p in prop_list.get_all_props():
if len(p.value) > PROP_VALUE_MAX and not p.name.startswith("ro."):
check_pass = False
sys.stderr.write("error: %s cannot exceed %d bytes: " %
(p.name, PROP_VALUE_MAX))
sys.stderr.write("%s (%d)\n" % (p.value, len(p.value)))
if p.is_optional():
check_pass = False
sys.stderr.write("error: found unresolved optional prop assignment:\n")
sys.stderr.write(str(p) + "\n")
return check_pass
def override_optional_props(prop_list):
"""Override a?=b with a=c, if the latter exists
Overriding is done by deleting a?=b
When there are a?=b and a?=c, then only the last one survives
When there are a=b and a=c, then it's an error.
Returns:
True if the override was successful
"""
success = True
for name in prop_list.get_all_names():
props = prop_list.get_props(name)
optional_props = [p for p in props if p.is_optional()]
overriding_props = [p for p in props if not p.is_optional()]
if len(overriding_props) > 1:
# duplicated props are allowed when the all have the same value
if all(overriding_props[0].value == p.value for p in overriding_props):
continue
success = False
sys.stderr.write("error: found duplicate sysprop assignments:\n")
for p in overriding_props:
sys.stderr.write("%s\n" % str(p))
elif len(overriding_props) == 1:
for p in optional_props:
p.delete("overridden by %s" % str(overriding_props[0]))
else:
if len(optional_props) > 1:
for p in optional_props[:-1]:
p.delete("overridden by %s" % str(optional_props[-1]))
# Make the last optional one as non-optional
optional_props[-1].optional = False
return success
class Prop:
def __init__(self, name, value, comment=None):
def __init__(self, name, value, optional=False, comment=None):
self.name = name.strip()
self.value = value.strip()
self.comment = comment
if comment != None:
self.comments = [comment]
else:
self.comments = []
self.optional = optional
@staticmethod
def from_line(line):
line = line.rstrip('\n')
if line.startswith("#"):
return Prop("", "", line)
return Prop("", "", comment=line)
elif "?=" in line:
name, value = line.split("?=", 1)
return Prop(name, value, optional=True)
elif "=" in line:
name, value = line.split("=", 1)
return Prop(name, value)
return Prop(name, value, optional=False)
else:
# don't fail on invalid line
# TODO(jiyong) make this a hard error
return Prop("", "", line)
return Prop("", "", comment=line)
def is_comment(self):
return self.comment != None
return bool(self.comments and not self.name)
def is_optional(self):
return (not self.is_comment()) and self.optional
def make_as_comment(self):
# Prepend "#" to the last line which is the prop assignment
if not self.is_comment():
assignment = str(self).rsplit("\n", 1)[-1]
self.comments.append("#" + assignment)
self.name = ""
self.value = ""
def delete(self, reason):
self.comments.append("# Removed by post_process_props.py because " + reason)
self.make_as_comment()
def __str__(self):
if self.is_comment():
return self.comment
else:
return self.name + "=" + self.value
assignment = []
if not self.is_comment():
operator = "?=" if self.is_optional() else "="
assignment.append(self.name + operator + self.value)
return "\n".join(self.comments + assignment)
class PropList:
@ -94,25 +163,35 @@ class PropList:
self.props = [Prop.from_line(l)
for l in f.readlines() if l.strip() != ""]
def get_all(self):
def get_all_props(self):
return [p for p in self.props if not p.is_comment()]
def get(self, name):
def get_all_names(self):
return set([p.name for p in self.get_all_props()])
def get_props(self, name):
return [p for p in self.get_all_props() if p.name == name]
def get_value(self, name):
# Caution: only the value of the first sysprop having the name is returned.
return next((p.value for p in self.props if p.name == name), "")
def put(self, name, value):
index = next((i for i,p in enumerate(self.props) if p.name == name), -1)
# Note: when there is an optional prop for the name, its value isn't changed.
# Instead a new non-optional prop is appended, which will override the
# optional prop. Otherwise, the new value might be overridden by an existing
# non-optional prop of the same name.
index = next((i for i,p in enumerate(self.props)
if p.name == name and not p.is_optional()), -1)
if index == -1:
self.props.append(Prop(name, value))
self.props.append(Prop(name, value,
comment="# Auto-added by post_process_props.py"))
else:
self.props[index].comments.append(
"# Value overridden by post_process_props.py. Original value: %s" %
self.props[index].value)
self.props[index].value = value
def delete(self, name):
index = next((i for i,p in enumerate(self.props) if p.name == name), -1)
if index != -1:
new_comment = "# removed by post_process_props.py\n#" + str(self.props[index])
self.props[index] = Prop.from_line(new_comment)
def write(self, filename):
with open(filename, 'w+') as f:
for p in self.props:
@ -127,12 +206,15 @@ def main(argv):
props = PropList(filename)
mangle_build_prop(props)
if not override_optional_props(props):
sys.exit(1)
if not validate(props):
sys.exit(1)
# Drop any blacklisted keys
# Drop any disallowed keys
for key in argv[2:]:
props.delete(key)
for p in props.get_props(key):
p.delete("%s is a disallowed key" % key)
props.write(filename)

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@ -0,0 +1,6 @@
<configuration description="Config to run post_process_props_unittest">
<test class="com.android.tradefed.testtype.python.PythonBinaryHostTest" >
<option name="par-file-name" value="post_process_props_unittest" />
<option name="test-timeout" value="1m" />
</test>
</configuration>

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@ -0,0 +1,230 @@
#!/usr/bin/env python3
#
# Copyright (C) 2020 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import contextlib
import io
import unittest
from unittest.mock import *
from post_process_props import *
class PropTestCase(unittest.TestCase):
def test_createFromLine(self):
p = Prop.from_line("# this is comment")
self.assertTrue(p.is_comment())
self.assertEqual("", p.name)
self.assertEqual("", p.value)
self.assertFalse(p.is_optional())
self.assertEqual("# this is comment", str(p))
for line in ["a=b", "a = b", "a= b", "a =b", " a=b "]:
p = Prop.from_line(line)
self.assertFalse(p.is_comment())
self.assertEqual("a", p.name)
self.assertEqual("b", p.value)
self.assertFalse(p.is_optional())
self.assertEqual("a=b", str(p))
for line in ["a?=b", "a ?= b", "a?= b", "a ?=b", " a?=b "]:
p = Prop.from_line(line)
self.assertFalse(p.is_comment())
self.assertEqual("a", p.name)
self.assertEqual("b", p.value)
self.assertTrue(p.is_optional())
self.assertEqual("a?=b", str(p))
def test_makeAsComment(self):
p = Prop.from_line("a=b")
p.comments.append("# a comment")
self.assertFalse(p.is_comment())
p.make_as_comment()
self.assertTrue(p.is_comment())
self.assertTrue("# a comment\n#a=b", str(p))
class PropListTestcase(unittest.TestCase):
def setUp(self):
content = """
# comment
foo=true
bar=false
qux?=1
# another comment
foo?=false
"""
self.patcher = patch("post_process_props.open", mock_open(read_data=content))
self.mock_open = self.patcher.start()
self.props = PropList("file")
def tearDown(self):
self.patcher.stop()
self.props = None
def test_readFromFile(self):
self.assertEqual(4, len(self.props.get_all_props()))
expected = [
("foo", "true", False),
("bar", "false", False),
("qux", "1", True),
("foo", "false", True)
]
for i,p in enumerate(self.props.get_all_props()):
self.assertEqual(expected[i][0], p.name)
self.assertEqual(expected[i][1], p.value)
self.assertEqual(expected[i][2], p.is_optional())
self.assertFalse(p.is_comment())
self.assertEqual(set(["foo", "bar", "qux"]), self.props.get_all_names())
self.assertEqual("true", self.props.get_value("foo"))
self.assertEqual("false", self.props.get_value("bar"))
self.assertEqual("1", self.props.get_value("qux"))
# there are two assignments for 'foo'
self.assertEqual(2, len(self.props.get_props("foo")))
def test_putNewProp(self):
self.props.put("new", "30")
self.assertEqual(5, len(self.props.get_all_props()))
last_prop = self.props.get_all_props()[-1]
self.assertEqual("new", last_prop.name)
self.assertEqual("30", last_prop.value)
self.assertFalse(last_prop.is_optional())
def test_putExistingNonOptionalProp(self):
self.props.put("foo", "NewValue")
self.assertEqual(4, len(self.props.get_all_props()))
foo_prop = self.props.get_props("foo")[0]
self.assertEqual("foo", foo_prop.name)
self.assertEqual("NewValue", foo_prop.value)
self.assertFalse(foo_prop.is_optional())
self.assertEqual("# Value overridden by post_process_props.py. " +
"Original value: true\nfoo=NewValue", str(foo_prop))
def test_putExistingOptionalProp(self):
self.props.put("qux", "2")
self.assertEqual(5, len(self.props.get_all_props()))
last_prop = self.props.get_all_props()[-1]
self.assertEqual("qux", last_prop.name)
self.assertEqual("2", last_prop.value)
self.assertFalse(last_prop.is_optional())
self.assertEqual("# Auto-added by post_process_props.py\nqux=2",
str(last_prop))
def test_deleteNonOptionalProp(self):
props_to_delete = self.props.get_props("foo")[0]
props_to_delete.delete(reason="testing")
self.assertEqual(3, len(self.props.get_all_props()))
self.assertEqual("# Removed by post_process_props.py because testing\n" +
"#foo=true", str(props_to_delete))
def test_deleteOptionalProp(self):
props_to_delete = self.props.get_props("qux")[0]
props_to_delete.delete(reason="testing")
self.assertEqual(3, len(self.props.get_all_props()))
self.assertEqual("# Removed by post_process_props.py because testing\n" +
"#qux?=1", str(props_to_delete))
def test_overridingNonOptional(self):
props_to_be_overridden = self.props.get_props("foo")[1]
self.assertTrue("true", props_to_be_overridden.value)
self.assertTrue(override_optional_props(self.props))
# size reduced to 3 because foo?=false was overridden by foo=true
self.assertEqual(3, len(self.props.get_all_props()))
self.assertEqual(1, len(self.props.get_props("foo")))
self.assertEqual("true", self.props.get_props("foo")[0].value)
self.assertEqual("# Removed by post_process_props.py because " +
"overridden by foo=true\n#foo?=false",
str(props_to_be_overridden))
def test_overridingOptional(self):
content = """
# comment
qux?=2
foo=true
bar=false
qux?=1
# another comment
foo?=false
"""
with patch('post_process_props.open', mock_open(read_data=content)) as m:
props = PropList("hello")
props_to_be_overridden = props.get_props("qux")[0]
self.assertEqual("2", props_to_be_overridden.value)
self.assertTrue(override_optional_props(props))
self.assertEqual(1, len(props.get_props("qux")))
self.assertEqual("1", props.get_props("qux")[0].value)
# the only left optional assignment becomes non-optional
self.assertFalse(props.get_props("qux")[0].is_optional())
self.assertEqual("# Removed by post_process_props.py because " +
"overridden by qux?=1\n#qux?=2",
str(props_to_be_overridden))
def test_overridingDuplicated(self):
content = """
# comment
foo=true
bar=false
qux?=1
foo=false
# another comment
foo?=false
"""
with patch("post_process_props.open", mock_open(read_data=content)) as m:
stderr_redirect = io.StringIO()
with contextlib.redirect_stderr(stderr_redirect):
props = PropList("hello")
# fails due to duplicated foo=true and foo=false
self.assertFalse(override_optional_props(props))
self.assertEqual("error: found duplicate sysprop assignments:\n" +
"foo=true\nfoo=false\n", stderr_redirect.getvalue())
def test_overridingDuplicatedWithSameValue(self):
content = """
# comment
foo=true
bar=false
qux?=1
foo=true
# another comment
foo?=false
"""
with patch("post_process_props.open", mock_open(read_data=content)) as m:
stderr_redirect = io.StringIO()
with contextlib.redirect_stderr(stderr_redirect):
props = PropList("hello")
# we have duplicated foo=true and foo=true, but that's allowed
# since they have the same value
self.assertTrue(override_optional_props(props))
if __name__ == '__main__':
unittest.main(verbosity=2)