qemu-patch-raspberry4/scripts/qapi/expr.py
John Snow 7137a96099 qapi: Prefer explicit relative imports
All of the QAPI include statements are changed to be package-aware, as
explicit relative imports.

A quirk of Python packages is that the name of the package exists only
*outside* of the package. This means that to a module inside of the qapi
folder, there is inherently no such thing as the "qapi" package. The
reason these imports work is because the "qapi" package exists in the
context of the caller -- the execution shim, where sys.path includes a
directory that has a 'qapi' folder in it.

When we write "from qapi import sibling", we are NOT referencing the folder
'qapi', but rather "any package named qapi in sys.path". If you should
so happen to have a 'qapi' package in your path, it will use *that*
package.

When we write "from .sibling import foo", we always reference explicitly
our sibling module; guaranteeing consistency in *where* we are importing
these modules from.

This can be useful when working with virtual environments and packages
in development mode. In development mode, a package is installed as a
series of symlinks that forwards to your same source files. The problem
arises because code quality checkers will follow "import qapi.x" to the
"installed" version instead of the sibling file and -- even though they
are the same file -- they have different module paths, and this causes
cyclic import problems, false positive type mismatch errors, and more.

It can also be useful when dealing with hierarchical packages, e.g. if
we allow qemu.core.qmp, qemu.qapi.parser, etc.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20201009161558.107041-6-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2020-10-10 11:37:47 +02:00

368 lines
12 KiB
Python

# -*- coding: utf-8 -*-
#
# Check (context-free) QAPI schema expression structure
#
# Copyright IBM, Corp. 2011
# Copyright (c) 2013-2019 Red Hat Inc.
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
# Markus Armbruster <armbru@redhat.com>
# Eric Blake <eblake@redhat.com>
# Marc-André Lureau <marcandre.lureau@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory.
import re
from collections import OrderedDict
from .common import c_name
from .error import QAPISemError
# Names must be letters, numbers, -, and _. They must start with letter,
# except for downstream extensions which must start with __RFQDN_.
# Dots are only valid in the downstream extension prefix.
valid_name = re.compile(r'^(__[a-zA-Z0-9.-]+_)?'
'[a-zA-Z][a-zA-Z0-9_-]*$')
def check_name_is_str(name, info, source):
if not isinstance(name, str):
raise QAPISemError(info, "%s requires a string name" % source)
def check_name_str(name, info, source,
allow_optional=False, enum_member=False,
permit_upper=False):
membername = name
if allow_optional and name.startswith('*'):
membername = name[1:]
# Enum members can start with a digit, because the generated C
# code always prefixes it with the enum name
if enum_member and membername[0].isdigit():
membername = 'D' + membername
# Reserve the entire 'q_' namespace for c_name(), and for 'q_empty'
# and 'q_obj_*' implicit type names.
if not valid_name.match(membername) or \
c_name(membername, False).startswith('q_'):
raise QAPISemError(info, "%s has an invalid name" % source)
if not permit_upper and name.lower() != name:
raise QAPISemError(
info, "%s uses uppercase in name" % source)
assert not membername.startswith('*')
def check_defn_name_str(name, info, meta):
check_name_str(name, info, meta, permit_upper=True)
if name.endswith('Kind') or name.endswith('List'):
raise QAPISemError(
info, "%s name should not end in '%s'" % (meta, name[-4:]))
def check_keys(value, info, source, required, optional):
def pprint(elems):
return ', '.join("'" + e + "'" for e in sorted(elems))
missing = set(required) - set(value)
if missing:
raise QAPISemError(
info,
"%s misses key%s %s"
% (source, 's' if len(missing) > 1 else '',
pprint(missing)))
allowed = set(required + optional)
unknown = set(value) - allowed
if unknown:
raise QAPISemError(
info,
"%s has unknown key%s %s\nValid keys are %s."
% (source, 's' if len(unknown) > 1 else '',
pprint(unknown), pprint(allowed)))
def check_flags(expr, info):
for key in ['gen', 'success-response']:
if key in expr and expr[key] is not False:
raise QAPISemError(
info, "flag '%s' may only use false value" % key)
for key in ['boxed', 'allow-oob', 'allow-preconfig', 'coroutine']:
if key in expr and expr[key] is not True:
raise QAPISemError(
info, "flag '%s' may only use true value" % key)
if 'allow-oob' in expr and 'coroutine' in expr:
# This is not necessarily a fundamental incompatibility, but
# we don't have a use case and the desired semantics isn't
# obvious. The simplest solution is to forbid it until we get
# a use case for it.
raise QAPISemError(info, "flags 'allow-oob' and 'coroutine' "
"are incompatible")
def check_if(expr, info, source):
def check_if_str(ifcond, info):
if not isinstance(ifcond, str):
raise QAPISemError(
info,
"'if' condition of %s must be a string or a list of strings"
% source)
if ifcond.strip() == '':
raise QAPISemError(
info,
"'if' condition '%s' of %s makes no sense"
% (ifcond, source))
ifcond = expr.get('if')
if ifcond is None:
return
if isinstance(ifcond, list):
if ifcond == []:
raise QAPISemError(
info, "'if' condition [] of %s is useless" % source)
for elt in ifcond:
check_if_str(elt, info)
else:
check_if_str(ifcond, info)
expr['if'] = [ifcond]
def normalize_members(members):
if isinstance(members, OrderedDict):
for key, arg in members.items():
if isinstance(arg, dict):
continue
members[key] = {'type': arg}
def check_type(value, info, source,
allow_array=False, allow_dict=False):
if value is None:
return
# Array type
if isinstance(value, list):
if not allow_array:
raise QAPISemError(info, "%s cannot be an array" % source)
if len(value) != 1 or not isinstance(value[0], str):
raise QAPISemError(info,
"%s: array type must contain single type name" %
source)
return
# Type name
if isinstance(value, str):
return
# Anonymous type
if not allow_dict:
raise QAPISemError(info, "%s should be a type name" % source)
if not isinstance(value, OrderedDict):
raise QAPISemError(info,
"%s should be an object or type name" % source)
permit_upper = allow_dict in info.pragma.name_case_whitelist
# value is a dictionary, check that each member is okay
for (key, arg) in value.items():
key_source = "%s member '%s'" % (source, key)
check_name_str(key, info, key_source,
allow_optional=True, permit_upper=permit_upper)
if c_name(key, False) == 'u' or c_name(key, False).startswith('has_'):
raise QAPISemError(info, "%s uses reserved name" % key_source)
check_keys(arg, info, key_source, ['type'], ['if', 'features'])
check_if(arg, info, key_source)
check_features(arg.get('features'), info)
check_type(arg['type'], info, key_source, allow_array=True)
def check_features(features, info):
if features is None:
return
if not isinstance(features, list):
raise QAPISemError(info, "'features' must be an array")
features[:] = [f if isinstance(f, dict) else {'name': f}
for f in features]
for f in features:
source = "'features' member"
assert isinstance(f, dict)
check_keys(f, info, source, ['name'], ['if'])
check_name_is_str(f['name'], info, source)
source = "%s '%s'" % (source, f['name'])
check_name_str(f['name'], info, source)
check_if(f, info, source)
def check_enum(expr, info):
name = expr['enum']
members = expr['data']
prefix = expr.get('prefix')
if not isinstance(members, list):
raise QAPISemError(info, "'data' must be an array")
if prefix is not None and not isinstance(prefix, str):
raise QAPISemError(info, "'prefix' must be a string")
permit_upper = name in info.pragma.name_case_whitelist
members[:] = [m if isinstance(m, dict) else {'name': m}
for m in members]
for member in members:
source = "'data' member"
check_keys(member, info, source, ['name'], ['if'])
check_name_is_str(member['name'], info, source)
source = "%s '%s'" % (source, member['name'])
check_name_str(member['name'], info, source,
enum_member=True, permit_upper=permit_upper)
check_if(member, info, source)
def check_struct(expr, info):
name = expr['struct']
members = expr['data']
check_type(members, info, "'data'", allow_dict=name)
check_type(expr.get('base'), info, "'base'")
def check_union(expr, info):
name = expr['union']
base = expr.get('base')
discriminator = expr.get('discriminator')
members = expr['data']
if discriminator is None: # simple union
if base is not None:
raise QAPISemError(info, "'base' requires 'discriminator'")
else: # flat union
check_type(base, info, "'base'", allow_dict=name)
if not base:
raise QAPISemError(info, "'discriminator' requires 'base'")
check_name_is_str(discriminator, info, "'discriminator'")
for (key, value) in members.items():
source = "'data' member '%s'" % key
check_name_str(key, info, source)
check_keys(value, info, source, ['type'], ['if'])
check_if(value, info, source)
check_type(value['type'], info, source, allow_array=not base)
def check_alternate(expr, info):
members = expr['data']
if not members:
raise QAPISemError(info, "'data' must not be empty")
for (key, value) in members.items():
source = "'data' member '%s'" % key
check_name_str(key, info, source)
check_keys(value, info, source, ['type'], ['if'])
check_if(value, info, source)
check_type(value['type'], info, source)
def check_command(expr, info):
args = expr.get('data')
rets = expr.get('returns')
boxed = expr.get('boxed', False)
if boxed and args is None:
raise QAPISemError(info, "'boxed': true requires 'data'")
check_type(args, info, "'data'", allow_dict=not boxed)
check_type(rets, info, "'returns'", allow_array=True)
def check_event(expr, info):
args = expr.get('data')
boxed = expr.get('boxed', False)
if boxed and args is None:
raise QAPISemError(info, "'boxed': true requires 'data'")
check_type(args, info, "'data'", allow_dict=not boxed)
def check_exprs(exprs):
for expr_elem in exprs:
expr = expr_elem['expr']
info = expr_elem['info']
doc = expr_elem.get('doc')
if 'include' in expr:
continue
if 'enum' in expr:
meta = 'enum'
elif 'union' in expr:
meta = 'union'
elif 'alternate' in expr:
meta = 'alternate'
elif 'struct' in expr:
meta = 'struct'
elif 'command' in expr:
meta = 'command'
elif 'event' in expr:
meta = 'event'
else:
raise QAPISemError(info, "expression is missing metatype")
name = expr[meta]
check_name_is_str(name, info, "'%s'" % meta)
info.set_defn(meta, name)
check_defn_name_str(name, info, meta)
if doc:
if doc.symbol != name:
raise QAPISemError(
info, "documentation comment is for '%s'" % doc.symbol)
doc.check_expr(expr)
elif info.pragma.doc_required:
raise QAPISemError(info,
"documentation comment required")
if meta == 'enum':
check_keys(expr, info, meta,
['enum', 'data'], ['if', 'features', 'prefix'])
check_enum(expr, info)
elif meta == 'union':
check_keys(expr, info, meta,
['union', 'data'],
['base', 'discriminator', 'if', 'features'])
normalize_members(expr.get('base'))
normalize_members(expr['data'])
check_union(expr, info)
elif meta == 'alternate':
check_keys(expr, info, meta,
['alternate', 'data'], ['if', 'features'])
normalize_members(expr['data'])
check_alternate(expr, info)
elif meta == 'struct':
check_keys(expr, info, meta,
['struct', 'data'], ['base', 'if', 'features'])
normalize_members(expr['data'])
check_struct(expr, info)
elif meta == 'command':
check_keys(expr, info, meta,
['command'],
['data', 'returns', 'boxed', 'if', 'features',
'gen', 'success-response', 'allow-oob',
'allow-preconfig', 'coroutine'])
normalize_members(expr.get('data'))
check_command(expr, info)
elif meta == 'event':
check_keys(expr, info, meta,
['event'], ['data', 'boxed', 'if', 'features'])
normalize_members(expr.get('data'))
check_event(expr, info)
else:
assert False, 'unexpected meta type'
check_if(expr, info, meta)
check_features(expr.get('features'), info)
check_flags(expr, info)
return exprs