qapi: replace if condition list with dict {'all': [...]}

Replace the simple list sugar form with a recursive structure that will
accept other operators in the following commits (all, any or not).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20210804083105.97531-7-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Accidental code motion undone.  Degenerate :forms: comment dropped.
Helper _check_if() moved.  Error messages tweaked.  ui.json updated.
Accidental changes to qapi-schema-test.json dropped.]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

3 files changed, 54 insertions, 31 deletions

diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
index ddc54e4368..3d7272a702 100644
--- a/scripts/qapi/common.py
+++ b/scripts/qapi/common.py
@@ -13,7 +13,8 @@
 
 import re
 from typing import (
-    List,
+    Any,
+    Dict,
     Match,
     Optional,
     Union,
@@ -199,17 +200,29 @@ def guardend(name: str) -> str:
                  name=c_fname(name).upper())
 
 
-def cgen_ifcond(ifcond: Union[str, List[str]]) -> str:
+def cgen_ifcond(ifcond: Union[str, Dict[str, Any]]) -> str:
     if not ifcond:
         return ''
-    return '(' + ') && ('.join(ifcond) + ')'
+    if isinstance(ifcond, str):
+        return ifcond
 
+    oper, operands = next(iter(ifcond.items()))
+    oper = {'all': '&&'}[oper]
+    operands = [cgen_ifcond(o) for o in operands]
+    return '(' + (') ' + oper + ' (').join(operands) + ')'
 
-def docgen_ifcond(ifcond: Union[str, List[str]]) -> str:
+
+def docgen_ifcond(ifcond: Union[str, Dict[str, Any]]) -> str:
     # TODO Doc generated for conditions needs polish
     if not ifcond:
         return ''
-    return ' and '.join(ifcond)
+    if isinstance(ifcond, str):
+        return ifcond
+
+    oper, operands = next(iter(ifcond.items()))
+    oper = {'all': ' and '}[oper]
+    operands = [docgen_ifcond(o) for o in operands]
+    return '(' + oper.join(operands) + ')'
 
 
 def gen_if(cond: str) -> str:
diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index cf98923fa6..d7a34655a7 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -259,14 +259,9 @@ 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.
+    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]``
+    The ``if`` member may be either a ``str`` or a dict.
 
     :param expr: The expression containing the ``if`` member to validate.
     :param info: QAPI schema source file information.
@@ -275,31 +270,46 @@ def check_if(expr: _JSONObject, info: QAPISourceInfo, source: str) -> None:
     :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.
+    :return: None
     """
-    ifcond = expr.get('if')
-    if ifcond is None:
-        return
 
-    if isinstance(ifcond, list):
-        if not ifcond:
-            raise QAPISemError(
-                info, "'if' condition [] of %s is useless" % source)
-    else:
-        # Normalize to a list
-        ifcond = expr['if'] = [ifcond]
+    def _check_if(cond: Union[str, object]) -> None:
+        if isinstance(cond, str):
+            if not cond.strip():
+                raise QAPISemError(
+                    info,
+                    "'if' condition '%s' of %s makes no sense"
+                    % (cond, source))
+            return
 
-    for elt in ifcond:
-        if not isinstance(elt, str):
+        if not isinstance(cond, dict):
             raise QAPISemError(
                 info,
-                "'if' condition of %s must be a string or a list of strings"
-                % source)
-        if not elt.strip():
+                "'if' condition of %s must be a string or an object" % source)
+        if len(cond) != 1:
             raise QAPISemError(
                 info,
-                "'if' condition '%s' of %s makes no sense"
-                % (elt, source))
+                "'if' condition dict of %s must have one key: "
+                "'all'" % source)
+        check_keys(cond, info, "'if' condition", [],
+                   ["all"])
+
+        oper, operands = next(iter(cond.items()))
+        if not operands:
+            raise QAPISemError(
+                info, "'if' condition [] of %s is useless" % source)
+
+        if oper in ("all") and not isinstance(operands, list):
+            raise QAPISemError(
+                info, "'%s' condition of %s must be an array" % (oper, source))
+        for operand in operands:
+            _check_if(operand)
+
+    ifcond = expr.get('if')
+    if ifcond is None:
+        return
+
+    _check_if(ifcond)
 
 
 def normalize_members(members: object) -> None:
diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index a9345af7b7..229d24fce9 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -32,7 +32,7 @@ from .parser import QAPISchemaParser
 
 class QAPISchemaIfCond:
     def __init__(self, ifcond=None):
-        self.ifcond = ifcond or []
+        self.ifcond = ifcond or {}
 
     def cgen(self):
         return cgen_ifcond(self.ifcond)