scripts: add python_qmp_updater.py

A script, to update the pattern

    result = self.vm.qmp(...)
    self.assert_qmp(result, 'return', {})

(and some similar ones) into

    self.vm.cmd(...)

Used in the next commit
    "python: use vm.cmd() instead of vm.qmp() where appropriate"

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20231006154125.1068348-15-vsementsov@yandex-team.ru
Signed-off-by: John Snow <jsnow@redhat.com>

scripts/python_qmp_updater.py

@@ -0,0 +1,136 @@
+#!/usr/bin/env python3
+#
+# Intended usage:
+#
+# git grep -l '\.qmp(' | xargs ./scripts/python_qmp_updater.py
+#
+
+import re
+import sys
+from typing import Optional
+
+start_reg = re.compile(r'^(?P<padding> *)(?P<res>\w+) = (?P<vm>.*).qmp\(',
+                       flags=re.MULTILINE)
+
+success_reg_templ = re.sub('\n *', '', r"""
+    (\n*{padding}(?P<comment>\#.*$))?
+    \n*{padding}
+    (
+        self.assert_qmp\({res},\ 'return',\ {{}}\)
+    |
+        assert\ {res}\['return'\]\ ==\ {{}}
+    |
+        assert\ {res}\ ==\ {{'return':\ {{}}}}
+    |
+        self.assertEqual\({res}\['return'\],\ {{}}\)
+    )""")
+
+some_check_templ = re.sub('\n *', '', r"""
+    (\n*{padding}(?P<comment>\#.*$))?
+    \s*self.assert_qmp\({res},""")
+
+
+def tmatch(template: str, text: str,
+           padding: str, res: str) -> Optional[re.Match[str]]:
+    return re.match(template.format(padding=padding, res=res), text,
+                    flags=re.MULTILINE)
+
+
+def find_closing_brace(text: str, start: int) -> int:
+    """
+    Having '(' at text[start] search for pairing ')' and return its index.
+    """
+    assert text[start] == '('
+
+    height = 1
+
+    for i in range(start + 1, len(text)):
+        if text[i] == '(':
+            height += 1
+        elif text[i] == ')':
+            height -= 1
+        if height == 0:
+            return i
+
+    raise ValueError
+
+
+def update(text: str) -> str:
+    result = ''
+
+    while True:
+        m = start_reg.search(text)
+        if m is None:
+            result += text
+            break
+
+        result += text[:m.start()]
+
+        args_ind = m.end()
+        args_end = find_closing_brace(text, args_ind - 1)
+
+        all_args = text[args_ind:args_end].split(',', 1)
+
+        name = all_args[0]
+        args = None if len(all_args) == 1 else all_args[1]
+
+        unchanged_call = text[m.start():args_end+1]
+        text = text[args_end+1:]
+
+        padding, res, vm = m.group('padding', 'res', 'vm')
+
+        m = tmatch(success_reg_templ, text, padding, res)
+
+        if m is None:
+            result += unchanged_call
+
+            if ('query-' not in name and
+                    'x-debug-block-dirty-bitmap-sha256' not in name and
+                    not tmatch(some_check_templ, text, padding, res)):
+                print(unchanged_call + text[:200] + '...\n\n')
+
+            continue
+
+        if m.group('comment'):
+            result += f'{padding}{m.group("comment")}\n'
+
+        result += f'{padding}{vm}.cmd({name}'
+
+        if args:
+            result += ','
+
+            if '\n' in args:
+                m_args = re.search('(?P<pad> *).*$', args)
+                assert m_args is not None
+
+                cur_padding = len(m_args.group('pad'))
+                expected = len(f'{padding}{res} = {vm}.qmp(')
+                drop = len(f'{res} = ')
+                if cur_padding == expected - 1:
+                    # tolerate this bad style
+                    drop -= 1
+                elif cur_padding < expected - 1:
+                    # assume nothing to do
+                    drop = 0
+
+                if drop:
+                    args = re.sub('\n' + ' ' * drop, '\n', args)
+
+            result += args
+
+        result += ')'
+
+        text = text[m.end():]
+
+    return result
+
+
+for fname in sys.argv[1:]:
+    print(fname)
+    with open(fname) as f:
+        t = f.read()
+
+    t = update(t)
+
+    with open(fname, 'w') as f:
+        f.write(t)