qapi: move generator entrypoint into package

As part of delinting and adding type hints to the QAPI generator, it's
helpful for the entrypoint to be part of the package, only leaving a
very tiny entrypoint shim outside of the package.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Tested-by: Cleber Rosa <crosa@redhat.com>
Message-Id: <20201009161558.107041-5-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[invalid_char() renamed to invalid_prefix_char()]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

2 files changed, 101 insertions, 88 deletions

diff --git a/scripts/qapi-gen.py b/scripts/qapi-gen.py
index cf942d9ce3..f3518d29a5 100644
--- a/scripts/qapi-gen.py
+++ b/scripts/qapi-gen.py
@@ -4,98 +4,16 @@
 # See the COPYING file in the top-level directory.
 
 """
-QAPI Generator
+QAPI code generation execution shim.
 
-This is the main entry point for generating C code from the QAPI schema.
+This standalone script exists primarily to facilitate the running of the QAPI
+code generator without needing to install the python module to the current
+execution environment.
 """
 
-import argparse
-import re
 import sys
-from typing import Optional
-
-from qapi.commands import gen_commands
-from qapi.error import QAPIError
-from qapi.events import gen_events
-from qapi.introspect import gen_introspect
-from qapi.schema import QAPISchema
-from qapi.types import gen_types
-from qapi.visit import gen_visit
-
-
-def invalid_prefix_char(prefix: str) -> Optional[str]:
-    match = re.match(r'([A-Za-z_.-][A-Za-z0-9_.-]*)?', prefix)
-    if match.end() != len(prefix):
-        return prefix[match.end()]
-    return None
-
-
-def generate(schema_file: str,
-             output_dir: str,
-             prefix: str,
-             unmask: bool = False,
-             builtins: bool = False) -> None:
-    """
-    Generate C code for the given schema into the target directory.
-
-    :param schema_file: The primary QAPI schema file.
-    :param output_dir: The output directory to store generated code.
-    :param prefix: Optional C-code prefix for symbol names.
-    :param unmask: Expose non-ABI names through introspection?
-    :param builtins: Generate code for built-in types?
-
-    :raise QAPIError: On failures.
-    """
-    assert invalid_prefix_char(prefix) is None
-
-    schema = QAPISchema(schema_file)
-    gen_types(schema, output_dir, prefix, builtins)
-    gen_visit(schema, output_dir, prefix, builtins)
-    gen_commands(schema, output_dir, prefix)
-    gen_events(schema, output_dir, prefix)
-    gen_introspect(schema, output_dir, prefix, unmask)
-
-
-def main() -> int:
-    """
-    gapi-gen executable entry point.
-    Expects arguments via sys.argv, see --help for details.
-
-    :return: int, 0 on success, 1 on failure.
-    """
-    parser = argparse.ArgumentParser(
-        description='Generate code from a QAPI schema')
-    parser.add_argument('-b', '--builtins', action='store_true',
-                        help="generate code for built-in types")
-    parser.add_argument('-o', '--output-dir', action='store',
-                        default='',
-                        help="write output to directory OUTPUT_DIR")
-    parser.add_argument('-p', '--prefix', action='store',
-                        default='',
-                        help="prefix for symbols")
-    parser.add_argument('-u', '--unmask-non-abi-names', action='store_true',
-                        dest='unmask',
-                        help="expose non-ABI names in introspection")
-    parser.add_argument('schema', action='store')
-    args = parser.parse_args()
-
-    funny_char = invalid_prefix_char(args.prefix)
-    if funny_char:
-        msg = f"funny character '{funny_char}' in argument of --prefix"
-        print(f"{sys.argv[0]}: {msg}", file=sys.stderr)
-        return 1
-
-    try:
-        generate(args.schema,
-                 output_dir=args.output_dir,
-                 prefix=args.prefix,
-                 unmask=args.unmask,
-                 builtins=args.builtins)
-    except QAPIError as err:
-        print(f"{sys.argv[0]}: {str(err)}", file=sys.stderr)
-        return 1
-    return 0
 
+from qapi import main
 
 if __name__ == '__main__':
-    sys.exit(main())
+    sys.exit(main.main())
diff --git a/scripts/qapi/main.py b/scripts/qapi/main.py
new file mode 100644
index 0000000000..92a2a31ca1
--- /dev/null
+++ b/scripts/qapi/main.py
@@ -0,0 +1,95 @@
+# This work is licensed under the terms of the GNU GPL, version 2 or later.
+# See the COPYING file in the top-level directory.
+
+"""
+QAPI Generator
+
+This is the main entry point for generating C code from the QAPI schema.
+"""
+
+import argparse
+import re
+import sys
+from typing import Optional
+
+from qapi.commands import gen_commands
+from qapi.error import QAPIError
+from qapi.events import gen_events
+from qapi.introspect import gen_introspect
+from qapi.schema import QAPISchema
+from qapi.types import gen_types
+from qapi.visit import gen_visit
+
+
+def invalid_prefix_char(prefix: str) -> Optional[str]:
+    match = re.match(r'([A-Za-z_.-][A-Za-z0-9_.-]*)?', prefix)
+    if match.end() != len(prefix):
+        return prefix[match.end()]
+    return None
+
+
+def generate(schema_file: str,
+             output_dir: str,
+             prefix: str,
+             unmask: bool = False,
+             builtins: bool = False) -> None:
+    """
+    Generate C code for the given schema into the target directory.
+
+    :param schema_file: The primary QAPI schema file.
+    :param output_dir: The output directory to store generated code.
+    :param prefix: Optional C-code prefix for symbol names.
+    :param unmask: Expose non-ABI names through introspection?
+    :param builtins: Generate code for built-in types?
+
+    :raise QAPIError: On failures.
+    """
+    assert invalid_prefix_char(prefix) is None
+
+    schema = QAPISchema(schema_file)
+    gen_types(schema, output_dir, prefix, builtins)
+    gen_visit(schema, output_dir, prefix, builtins)
+    gen_commands(schema, output_dir, prefix)
+    gen_events(schema, output_dir, prefix)
+    gen_introspect(schema, output_dir, prefix, unmask)
+
+
+def main() -> int:
+    """
+    gapi-gen executable entry point.
+    Expects arguments via sys.argv, see --help for details.
+
+    :return: int, 0 on success, 1 on failure.
+    """
+    parser = argparse.ArgumentParser(
+        description='Generate code from a QAPI schema')
+    parser.add_argument('-b', '--builtins', action='store_true',
+                        help="generate code for built-in types")
+    parser.add_argument('-o', '--output-dir', action='store',
+                        default='',
+                        help="write output to directory OUTPUT_DIR")
+    parser.add_argument('-p', '--prefix', action='store',
+                        default='',
+                        help="prefix for symbols")
+    parser.add_argument('-u', '--unmask-non-abi-names', action='store_true',
+                        dest='unmask',
+                        help="expose non-ABI names in introspection")
+    parser.add_argument('schema', action='store')
+    args = parser.parse_args()
+
+    funny_char = invalid_prefix_char(args.prefix)
+    if funny_char:
+        msg = f"funny character '{funny_char}' in argument of --prefix"
+        print(f"{sys.argv[0]}: {msg}", file=sys.stderr)
+        return 1
+
+    try:
+        generate(args.schema,
+                 output_dir=args.output_dir,
+                 prefix=args.prefix,
+                 unmask=args.unmask,
+                 builtins=args.builtins)
+    except QAPIError as err:
+        print(f"{sys.argv[0]}: {str(err)}", file=sys.stderr)
+        return 1
+    return 0