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authorJohn Snow <jsnow@redhat.com>2021-04-21 14:20:30 -0400
committerMarkus Armbruster <armbru@redhat.com>2021-04-30 12:59:54 +0200
commita48653638fab9c9a9356b41d6e11544b2a7b330f (patch)
treea4ca97ad83cc566f4811f3e714a3beb1c9ab9738
parent79e4fd14fb0f9e145413c6813dc541fdb50e3923 (diff)
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qapi/expr.py: Add docstrings
Now with more :words:! Signed-off-by: John Snow <jsnow@redhat.com> Message-Id: <20210421182032.3521476-16-jsnow@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
-rw-r--r--scripts/qapi/expr.py256
1 files changed, 251 insertions, 5 deletions
diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index c33caf0..0b66d80 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -1,7 +1,5 @@
# -*- coding: utf-8 -*-
#
-# Check (context-free) QAPI schema expression structure
-#
# Copyright IBM, Corp. 2011
# Copyright (c) 2013-2019 Red Hat Inc.
#
@@ -14,6 +12,24 @@
# This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory.
+"""
+Normalize and validate (context-free) QAPI schema expression structures.
+
+`QAPISchemaParser` parses a QAPI schema into abstract syntax trees
+consisting of dict, list, str, bool, and int nodes. This module ensures
+that these nested structures have the correct type(s) and key(s) where
+appropriate for the QAPI context-free grammar.
+
+The QAPI schema expression language allows for certain syntactic sugar;
+this module also handles the normalization process of these nested
+structures.
+
+See `check_exprs` for the main entry point.
+
+See `schema.QAPISchema` for processing into native Python data
+structures and contextual semantic validation.
+"""
+
import re
from typing import (
Collection,
@@ -39,9 +55,7 @@ from .source import QAPISourceInfo
_JSONObject = Dict[str, object]
-# Names consist of letters, digits, -, and _, starting with a letter.
-# An experimental name is prefixed with x-. A name of a downstream
-# extension is prefixed with __RFQDN_. The latter prefix goes first.
+# See check_name_str(), below.
valid_name = re.compile(r'(__[a-z0-9.-]+_)?'
r'(x-)?'
r'([a-z][a-z0-9_-]*)$', re.IGNORECASE)
@@ -50,11 +64,33 @@ valid_name = re.compile(r'(__[a-z0-9.-]+_)?'
def check_name_is_str(name: object,
info: QAPISourceInfo,
source: str) -> None:
+ """
+ Ensure that ``name`` is a ``str``.
+
+ :raise QAPISemError: When ``name`` fails validation.
+ """
if not isinstance(name, str):
raise QAPISemError(info, "%s requires a string name" % source)
def check_name_str(name: str, info: QAPISourceInfo, source: str) -> str:
+ """
+ Ensure that ``name`` is a valid QAPI name.
+
+ A valid name consists of ASCII letters, digits, ``-``, and ``_``,
+ starting with a letter. It may be prefixed by a downstream prefix
+ of the form __RFQDN_, or the experimental prefix ``x-``. If both
+ prefixes are present, the __RFDQN_ prefix goes first.
+
+ A valid name cannot start with ``q_``, which is reserved.
+
+ :param name: Name to check.
+ :param info: QAPI schema source file information.
+ :param source: Error string describing what ``name`` belongs to.
+
+ :raise QAPISemError: When ``name`` fails validation.
+ :return: The stem of the valid name, with no prefixes.
+ """
# Reserve the entire 'q_' namespace for c_name(), and for 'q_empty'
# and 'q_obj_*' implicit type names.
match = valid_name.match(name)
@@ -64,6 +100,19 @@ def check_name_str(name: str, info: QAPISourceInfo, source: str) -> str:
def check_name_upper(name: str, info: QAPISourceInfo, source: str) -> None:
+ """
+ Ensure that ``name`` is a valid event name.
+
+ This means it must be a valid QAPI name as checked by
+ `check_name_str()`, but where the stem prohibits lowercase
+ characters and ``-``.
+
+ :param name: Name to check.
+ :param info: QAPI schema source file information.
+ :param source: Error string describing what ``name`` belongs to.
+
+ :raise QAPISemError: When ``name`` fails validation.
+ """
stem = check_name_str(name, info, source)
if re.search(r'[a-z-]', stem):
raise QAPISemError(
@@ -73,6 +122,21 @@ def check_name_upper(name: str, info: QAPISourceInfo, source: str) -> None:
def check_name_lower(name: str, info: QAPISourceInfo, source: str,
permit_upper: bool = False,
permit_underscore: bool = False) -> None:
+ """
+ Ensure that ``name`` is a valid command or member name.
+
+ This means it must be a valid QAPI name as checked by
+ `check_name_str()`, but where the stem prohibits uppercase
+ characters and ``_``.
+
+ :param name: Name to check.
+ :param info: QAPI schema source file information.
+ :param source: Error string describing what ``name`` belongs to.
+ :param permit_upper: Additionally permit uppercase.
+ :param permit_underscore: Additionally permit ``_``.
+
+ :raise QAPISemError: When ``name`` fails validation.
+ """
stem = check_name_str(name, info, source)
if ((not permit_upper and re.search(r'[A-Z]', stem))
or (not permit_underscore and '_' in stem)):
@@ -81,12 +145,39 @@ def check_name_lower(name: str, info: QAPISourceInfo, source: str,
def check_name_camel(name: str, info: QAPISourceInfo, source: str) -> None:
+ """
+ Ensure that ``name`` is a valid user-defined type name.
+
+ This means it must be a valid QAPI name as checked by
+ `check_name_str()`, but where the stem must be in CamelCase.
+
+ :param name: Name to check.
+ :param info: QAPI schema source file information.
+ :param source: Error string describing what ``name`` belongs to.
+
+ :raise QAPISemError: When ``name`` fails validation.
+ """
stem = check_name_str(name, info, source)
if not re.match(r'[A-Z][A-Za-z0-9]*[a-z][A-Za-z0-9]*$', stem):
raise QAPISemError(info, "name of %s must use CamelCase" % source)
def check_defn_name_str(name: str, info: QAPISourceInfo, meta: str) -> None:
+ """
+ Ensure that ``name`` is a valid definition name.
+
+ Based on the value of ``meta``, this means that:
+ - 'event' names adhere to `check_name_upper()`.
+ - 'command' names adhere to `check_name_lower()`.
+ - Else, meta is a type, and must pass `check_name_camel()`.
+ These names must not end with ``Kind`` nor ``List``.
+
+ :param name: Name to check.
+ :param info: QAPI schema source file information.
+ :param meta: Meta-type name of the QAPI expression.
+
+ :raise QAPISemError: When ``name`` fails validation.
+ """
if meta == 'event':
check_name_upper(name, info, meta)
elif meta == 'command':
@@ -105,6 +196,17 @@ def check_keys(value: _JSONObject,
source: str,
required: Collection[str],
optional: Collection[str]) -> None:
+ """
+ Ensure that a dict has a specific set of keys.
+
+ :param value: The dict to check.
+ :param info: QAPI schema source file information.
+ :param source: Error string describing this ``value``.
+ :param required: Keys that *must* be present.
+ :param optional: Keys that *may* be present.
+
+ :raise QAPISemError: When unknown keys are present.
+ """
def pprint(elems: Iterable[str]) -> str:
return ', '.join("'" + e + "'" for e in sorted(elems))
@@ -127,6 +229,16 @@ def check_keys(value: _JSONObject,
def check_flags(expr: _JSONObject, info: QAPISourceInfo) -> None:
+ """
+ Ensure flag members (if present) have valid values.
+
+ :param expr: The expression to validate.
+ :param info: QAPI schema source file information.
+
+ :raise QAPISemError:
+ When certain flags have an invalid value, or when
+ incompatible flags are present.
+ """
for key in ['gen', 'success-response']:
if key in expr and expr[key] is not False:
raise QAPISemError(
@@ -145,7 +257,25 @@ def check_flags(expr: _JSONObject, info: QAPISourceInfo) -> None:
def check_if(expr: _JSONObject, info: QAPISourceInfo, source: str) -> None:
+ """
+ Normalize and validate the ``if`` member of an object.
+ The ``if`` member may be either a ``str`` or a ``List[str]``.
+ A ``str`` value will be normalized to ``List[str]``.
+
+ :forms:
+ :sugared: ``Union[str, List[str]]``
+ :canonical: ``List[str]``
+
+ :param expr: The expression containing the ``if`` member to validate.
+ :param info: QAPI schema source file information.
+ :param source: Error string describing ``expr``.
+
+ :raise QAPISemError:
+ When the "if" member fails validation, or when there are no
+ non-empty conditions.
+ :return: None, ``expr`` is normalized in-place as needed.
+ """
ifcond = expr.get('if')
if ifcond is None:
return
@@ -172,6 +302,21 @@ def check_if(expr: _JSONObject, info: QAPISourceInfo, source: str) -> None:
def normalize_members(members: object) -> None:
+ """
+ Normalize a "members" value.
+
+ If ``members`` is a dict, for every value in that dict, if that
+ value is not itself already a dict, normalize it to
+ ``{'type': value}``.
+
+ :forms:
+ :sugared: ``Dict[str, Union[str, TypeRef]]``
+ :canonical: ``Dict[str, TypeRef]``
+
+ :param members: The members value to normalize.
+
+ :return: None, ``members`` is normalized in-place as needed.
+ """
if isinstance(members, dict):
for key, arg in members.items():
if isinstance(arg, dict):
@@ -184,6 +329,26 @@ def check_type(value: Optional[object],
source: str,
allow_array: bool = False,
allow_dict: Union[bool, str] = False) -> None:
+ """
+ Normalize and validate the QAPI type of ``value``.
+
+ Python types of ``str`` or ``None`` are always allowed.
+
+ :param value: The value to check.
+ :param info: QAPI schema source file information.
+ :param source: Error string describing this ``value``.
+ :param allow_array:
+ Allow a ``List[str]`` of length 1, which indicates an array of
+ the type named by the list element.
+ :param allow_dict:
+ Allow a dict. Its members can be struct type members or union
+ branches. When the value of ``allow_dict`` is in pragma
+ ``member-name-exceptions``, the dict's keys may violate the
+ member naming rules. The dict members are normalized in place.
+
+ :raise QAPISemError: When ``value`` fails validation.
+ :return: None, ``value`` is normalized in-place as needed.
+ """
if value is None:
return
@@ -232,6 +397,22 @@ def check_type(value: Optional[object],
def check_features(features: Optional[object],
info: QAPISourceInfo) -> None:
+ """
+ Normalize and validate the ``features`` member.
+
+ ``features`` may be a ``list`` of either ``str`` or ``dict``.
+ Any ``str`` element will be normalized to ``{'name': element}``.
+
+ :forms:
+ :sugared: ``List[Union[str, Feature]]``
+ :canonical: ``List[Feature]``
+
+ :param features: The features member value to validate.
+ :param info: QAPI schema source file information.
+
+ :raise QAPISemError: When ``features`` fails validation.
+ :return: None, ``features`` is normalized in-place as needed.
+ """
if features is None:
return
if not isinstance(features, list):
@@ -249,6 +430,15 @@ def check_features(features: Optional[object],
def check_enum(expr: _JSONObject, info: QAPISourceInfo) -> None:
+ """
+ Normalize and validate this expression as an ``enum`` definition.
+
+ :param expr: The expression to validate.
+ :param info: QAPI schema source file information.
+
+ :raise QAPISemError: When ``expr`` is not a valid ``enum``.
+ :return: None, ``expr`` is normalized in-place as needed.
+ """
name = expr['enum']
members = expr['data']
prefix = expr.get('prefix')
@@ -278,6 +468,15 @@ def check_enum(expr: _JSONObject, info: QAPISourceInfo) -> None:
def check_struct(expr: _JSONObject, info: QAPISourceInfo) -> None:
+ """
+ Normalize and validate this expression as a ``struct`` definition.
+
+ :param expr: The expression to validate.
+ :param info: QAPI schema source file information.
+
+ :raise QAPISemError: When ``expr`` is not a valid ``struct``.
+ :return: None, ``expr`` is normalized in-place as needed.
+ """
name = cast(str, expr['struct']) # Checked in check_exprs
members = expr['data']
@@ -286,6 +485,15 @@ def check_struct(expr: _JSONObject, info: QAPISourceInfo) -> None:
def check_union(expr: _JSONObject, info: QAPISourceInfo) -> None:
+ """
+ Normalize and validate this expression as a ``union`` definition.
+
+ :param expr: The expression to validate.
+ :param info: QAPI schema source file information.
+
+ :raise QAPISemError: when ``expr`` is not a valid ``union``.
+ :return: None, ``expr`` is normalized in-place as needed.
+ """
name = cast(str, expr['union']) # Checked in check_exprs
base = expr.get('base')
discriminator = expr.get('discriminator')
@@ -314,6 +522,15 @@ def check_union(expr: _JSONObject, info: QAPISourceInfo) -> None:
def check_alternate(expr: _JSONObject, info: QAPISourceInfo) -> None:
+ """
+ Normalize and validate this expression as an ``alternate`` definition.
+
+ :param expr: The expression to validate.
+ :param info: QAPI schema source file information.
+
+ :raise QAPISemError: When ``expr`` is not a valid ``alternate``.
+ :return: None, ``expr`` is normalized in-place as needed.
+ """
members = expr['data']
if not members:
@@ -331,6 +548,15 @@ def check_alternate(expr: _JSONObject, info: QAPISourceInfo) -> None:
def check_command(expr: _JSONObject, info: QAPISourceInfo) -> None:
+ """
+ Normalize and validate this expression as a ``command`` definition.
+
+ :param expr: The expression to validate.
+ :param info: QAPI schema source file information.
+
+ :raise QAPISemError: When ``expr`` is not a valid ``command``.
+ :return: None, ``expr`` is normalized in-place as needed.
+ """
args = expr.get('data')
rets = expr.get('returns')
boxed = expr.get('boxed', False)
@@ -342,6 +568,15 @@ def check_command(expr: _JSONObject, info: QAPISourceInfo) -> None:
def check_event(expr: _JSONObject, info: QAPISourceInfo) -> None:
+ """
+ Normalize and validate this expression as an ``event`` definition.
+
+ :param expr: The expression to validate.
+ :param info: QAPI schema source file information.
+
+ :raise QAPISemError: When ``expr`` is not a valid ``event``.
+ :return: None, ``expr`` is normalized in-place as needed.
+ """
args = expr.get('data')
boxed = expr.get('boxed', False)
@@ -351,6 +586,17 @@ def check_event(expr: _JSONObject, info: QAPISourceInfo) -> None:
def check_exprs(exprs: List[_JSONObject]) -> List[_JSONObject]:
+ """
+ Validate and normalize a list of parsed QAPI schema expressions.
+
+ This function accepts a list of expressions and metadata as returned
+ by the parser. It destructively normalizes the expressions in-place.
+
+ :param exprs: The list of expressions to normalize and validate.
+
+ :raise QAPISemError: When any expression fails validation.
+ :return: The same list of expressions (now modified).
+ """
for expr_elem in exprs:
# Expression
assert isinstance(expr_elem['expr'], dict)