Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2020-10-10' into staging

QAPI patches patches for 2020-10-10

# gpg: Signature made Sat 10 Oct 2020 10:43:14 BST
# gpg:                using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg:                issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2020-10-10: (34 commits)
  qapi/visit.py: add type hint annotations
  qapi/visit.py: remove unused parameters from gen_visit_object
  qapi/visit.py: assert tag_member contains a QAPISchemaEnumType
  qapi/types.py: remove one-letter variables
  qapi/types.py: add type hint annotations
  qapi/gen.py: delint with pylint
  qapi/gen.py: update write() to be more idiomatic
  qapi/gen.py: Remove unused parameter
  qapi/gen.py: add type hint annotations
  qapi/gen: Make _is_user_module() return bool
  qapi/source.py: delint with pylint
  qapi/source.py: add type hint annotations
  qapi/commands.py: add type hint annotations
  qapi/commands.py: Don't re-bind to variable of different type
  qapi/events.py: Move comments into docstrings
  qapi/events.py: add type hint annotations
  qapi: establish mypy type-checking baseline
  qapi/common.py: move build_params into gen.py
  qapi/common.py: Convert comments into docstrings, and elaborate
  qapi/common.py: add type hint annotations
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 92 insertions, 72 deletions

diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
index ba35abea47..11b86beeab 100644
--- a/scripts/qapi/common.py
+++ b/scripts/qapi/common.py
@@ -12,12 +12,28 @@
 # See the COPYING file in the top-level directory.
 
 import re
+from typing import Optional, Sequence
 
 
-# ENUMName -> ENUM_NAME, EnumName1 -> ENUM_NAME1
-# ENUM_NAME -> ENUM_NAME, ENUM_NAME1 -> ENUM_NAME1, ENUM_Name2 -> ENUM_NAME2
-# ENUM24_Name -> ENUM24_NAME
-def camel_to_upper(value):
+#: Magic string that gets removed along with all space to its right.
+EATSPACE = '\033EATSPACE.'
+POINTER_SUFFIX = ' *' + EATSPACE
+_C_NAME_TRANS = str.maketrans('.-', '__')
+
+
+def camel_to_upper(value: str) -> str:
+    """
+    Converts CamelCase to CAMEL_CASE.
+
+    Examples::
+
+        ENUMName -> ENUM_NAME
+        EnumName1 -> ENUM_NAME1
+        ENUM_NAME -> ENUM_NAME
+        ENUM_NAME1 -> ENUM_NAME1
+        ENUM_Name2 -> ENUM_NAME2
+        ENUM24_Name -> ENUM24_NAME
+    """
     c_fun_str = c_name(value, False)
     if value.isupper():
         return c_fun_str
@@ -25,36 +41,47 @@ def camel_to_upper(value):
     new_name = ''
     length = len(c_fun_str)
     for i in range(length):
-        c = c_fun_str[i]
-        # When c is upper and no '_' appears before, do more checks
-        if c.isupper() and (i > 0) and c_fun_str[i - 1] != '_':
+        char = c_fun_str[i]
+        # When char is upper case and no '_' appears before, do more checks
+        if char.isupper() and (i > 0) and c_fun_str[i - 1] != '_':
             if i < length - 1 and c_fun_str[i + 1].islower():
                 new_name += '_'
             elif c_fun_str[i - 1].isdigit():
                 new_name += '_'
-        new_name += c
+        new_name += char
     return new_name.lstrip('_').upper()
 
 
-def c_enum_const(type_name, const_name, prefix=None):
+def c_enum_const(type_name: str,
+                 const_name: str,
+                 prefix: Optional[str] = None) -> str:
+    """
+    Generate a C enumeration constant name.
+
+    :param type_name: The name of the enumeration.
+    :param const_name: The name of this constant.
+    :param prefix: Optional, prefix that overrides the type_name.
+    """
     if prefix is not None:
         type_name = prefix
     return camel_to_upper(type_name) + '_' + c_name(const_name, False).upper()
 
 
-c_name_trans = str.maketrans('.-', '__')
+def c_name(name: str, protect: bool = True) -> str:
+    """
+    Map ``name`` to a valid C identifier.
 
+    Used for converting 'name' from a 'name':'type' qapi definition
+    into a generated struct member, as well as converting type names
+    into substrings of a generated C function name.
 
-# Map @name to a valid C identifier.
-# If @protect, avoid returning certain ticklish identifiers (like
-# C keywords) by prepending 'q_'.
-#
-# Used for converting 'name' from a 'name':'type' qapi definition
-# into a generated struct member, as well as converting type names
-# into substrings of a generated C function name.
-# '__a.b_c' -> '__a_b_c', 'x-foo' -> 'x_foo'
-# protect=True: 'int' -> 'q_int'; protect=False: 'int' -> 'int'
-def c_name(name, protect=True):
+    '__a.b_c' -> '__a_b_c', 'x-foo' -> 'x_foo'
+    protect=True: 'int' -> 'q_int'; protect=False: 'int' -> 'int'
+
+    :param name: The name to map.
+    :param protect: If true, avoid returning certain ticklish identifiers
+                    (like C keywords) by prepending ``q_``.
+    """
     # ANSI X3J11/88-090, 3.1.1
     c89_words = set(['auto', 'break', 'case', 'char', 'const', 'continue',
                      'default', 'do', 'double', 'else', 'enum', 'extern',
@@ -82,61 +109,75 @@ def c_name(name, protect=True):
                      'not_eq', 'or', 'or_eq', 'xor', 'xor_eq'])
     # namespace pollution:
     polluted_words = set(['unix', 'errno', 'mips', 'sparc', 'i386'])
-    name = name.translate(c_name_trans)
+    name = name.translate(_C_NAME_TRANS)
     if protect and (name in c89_words | c99_words | c11_words | gcc_words
                     | cpp_words | polluted_words):
         return 'q_' + name
     return name
 
 
-eatspace = '\033EATSPACE.'
-pointer_suffix = ' *' + eatspace
+class Indentation:
+    """
+    Indentation level management.
 
+    :param initial: Initial number of spaces, default 0.
+    """
+    def __init__(self, initial: int = 0) -> None:
+        self._level = initial
 
-def genindent(count):
-    ret = ''
-    for _ in range(count):
-        ret += ' '
-    return ret
+    def __int__(self) -> int:
+        return self._level
+
+    def __repr__(self) -> str:
+        return "{}({:d})".format(type(self).__name__, self._level)
+
+    def __str__(self) -> str:
+        """Return the current indentation as a string of spaces."""
+        return ' ' * self._level
 
+    def __bool__(self) -> bool:
+        """True when there is a non-zero indentation."""
+        return bool(self._level)
 
-indent_level = 0
+    def increase(self, amount: int = 4) -> None:
+        """Increase the indentation level by ``amount``, default 4."""
+        self._level += amount
 
+    def decrease(self, amount: int = 4) -> None:
+        """Decrease the indentation level by ``amount``, default 4."""
+        if self._level < amount:
+            raise ArithmeticError(
+                f"Can't remove {amount:d} spaces from {self!r}")
+        self._level -= amount
 
-def push_indent(indent_amount=4):
-    global indent_level
-    indent_level += indent_amount
 
+#: Global, current indent level for code generation.
+indent = Indentation()
 
-def pop_indent(indent_amount=4):
-    global indent_level
-    indent_level -= indent_amount
 
+def cgen(code: str, **kwds: object) -> str:
+    """
+    Generate ``code`` with ``kwds`` interpolated.
 
-# Generate @code with @kwds interpolated.
-# Obey indent_level, and strip eatspace.
-def cgen(code, **kwds):
+    Obey `indent`, and strip `EATSPACE`.
+    """
     raw = code % kwds
-    if indent_level:
-        indent = genindent(indent_level)
-        # re.subn() lacks flags support before Python 2.7, use re.compile()
-        raw = re.subn(re.compile(r'^(?!(#|$))', re.MULTILINE),
-                      indent, raw)
-        raw = raw[0]
-    return re.sub(re.escape(eatspace) + r' *', '', raw)
+    if indent:
+        raw = re.sub(r'^(?!(#|$))', str(indent), raw, flags=re.MULTILINE)
+    return re.sub(re.escape(EATSPACE) + r' *', '', raw)
 
 
-def mcgen(code, **kwds):
+def mcgen(code: str, **kwds: object) -> str:
     if code[0] == '\n':
         code = code[1:]
     return cgen(code, **kwds)
 
 
-def c_fname(filename):
+def c_fname(filename: str) -> str:
     return re.sub(r'[^A-Za-z0-9_]', '_', filename)
 
 
-def guardstart(name):
+def guardstart(name: str) -> str:
     return mcgen('''
 #ifndef %(name)s
 #define %(name)s
@@ -145,7 +186,7 @@ def guardstart(name):
                  name=c_fname(name).upper())
 
 
-def guardend(name):
+def guardend(name: str) -> str:
     return mcgen('''
 
 #endif /* %(name)s */
@@ -153,7 +194,7 @@ def guardend(name):
                  name=c_fname(name).upper())
 
 
-def gen_if(ifcond):
+def gen_if(ifcond: Sequence[str]) -> str:
     ret = ''
     for ifc in ifcond:
         ret += mcgen('''
@@ -162,31 +203,10 @@ def gen_if(ifcond):
     return ret
 
 
-def gen_endif(ifcond):
+def gen_endif(ifcond: Sequence[str]) -> str:
     ret = ''
     for ifc in reversed(ifcond):
         ret += mcgen('''
 #endif /* %(cond)s */
 ''', cond=ifc)
     return ret
-
-
-def build_params(arg_type, boxed, extra=None):
-    ret = ''
-    sep = ''
-    if boxed:
-        assert arg_type
-        ret += '%s arg' % arg_type.c_param_type()
-        sep = ', '
-    elif arg_type:
-        assert not arg_type.variants
-        for memb in arg_type.members:
-            ret += sep
-            sep = ', '
-            if memb.optional:
-                ret += 'bool has_%s, ' % c_name(memb.name)
-            ret += '%s %s' % (memb.type.c_param_type(),
-                              c_name(memb.name))
-    if extra:
-        ret += sep + extra
-    return ret if ret else 'void'