Rather than generate inline per-member visits, take advantage
of the 'visit_type_FOO_members()' function for emitting events.
This is possible now that implicit structs can be visited like
any other.  Generated code shrinks accordingly; by initializing
a struct based on parameters, through a new gen_param_var()
helper, like:
|@@ -338,6 +250,9 @@ void qapi_event_send_block_job_error(con
|     QMPEventFuncEmit emit = qmp_event_get_func_emit();
|     QmpOutputVisitor *qov;
|     Visitor *v;
|+    q_obj_BLOCK_JOB_ERROR_arg param = {
|+        (char *)device, operation, action
|+    };
|
|     if (!emit) {
|         return;
@@ -351,19 +266,7 @@ void qapi_event_send_block_job_error(con
|     if (err) {
|         goto out;
|     }
|-    visit_type_str(v, "device", (char **)&device, &err);
|-    if (err) {
|-        goto out_obj;
|-    }
|-    visit_type_IoOperationType(v, "operation", &operation, &err);
|-    if (err) {
|-        goto out_obj;
|-    }
|-    visit_type_BlockErrorAction(v, "action", &action, &err);
|-    if (err) {
|-        goto out_obj;
|-    }
|-out_obj:
|+    visit_type_q_obj_BLOCK_JOB_ERROR_arg_members(v, ¶m, &err);
|     visit_end_struct(v, err ? NULL : &err);
Notice that the initialization of 'param' has to cast away const
(just as the old gen_visit_members() had to do): we can't change
the signature of the user function (which uses 'const char *'), but
have to assign it to a non-const QAPI object (which requires
'char *').
While touching this, document with a FIXME comment that there is
still a potential collision between QMP members and our choice of
local variable names within qapi_event_send_FOO().
This patch also paves the way for some followup simplifications
in the generator, in subsequent patches.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1458254921-17042-8-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
		
	
			
		
			
				
	
	
		
			214 lines
		
	
	
		
			5.0 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			214 lines
		
	
	
		
			5.0 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
#
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# QAPI event generator
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#
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# Copyright (c) 2014 Wenchao Xia
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# Copyright (c) 2015-2016 Red Hat Inc.
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#
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# Authors:
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#  Wenchao Xia <wenchaoqemu@gmail.com>
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#  Markus Armbruster <armbru@redhat.com>
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#
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# This work is licensed under the terms of the GNU GPL, version 2.
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# See the COPYING file in the top-level directory.
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from qapi import *
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def gen_event_send_proto(name, arg_type):
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    return 'void qapi_event_send_%(c_name)s(%(param)s)' % {
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        'c_name': c_name(name.lower()),
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        'param': gen_params(arg_type, 'Error **errp')}
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def gen_event_send_decl(name, arg_type):
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    return mcgen('''
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%(proto)s;
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''',
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                 proto=gen_event_send_proto(name, arg_type))
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# Declare and initialize an object 'qapi' using parameters from gen_params()
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def gen_param_var(typ):
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    assert not typ.variants
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    ret = mcgen('''
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    %(c_name)s param = {
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''',
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                c_name=typ.c_name())
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    sep = '        '
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    for memb in typ.members:
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        ret += sep
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        sep = ', '
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        if memb.optional:
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            ret += 'has_' + c_name(memb.name) + sep
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        if memb.type.name == 'str':
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            # Cast away const added in gen_params()
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            ret += '(char *)'
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        ret += c_name(memb.name)
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    ret += mcgen('''
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    };
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''')
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    return ret
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def gen_event_send(name, arg_type):
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    # FIXME: Our declaration of local variables (and of 'errp' in the
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    # parameter list) can collide with exploded members of the event's
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    # data type passed in as parameters.  If this collision ever hits in
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    # practice, we can rename our local variables with a leading _ prefix,
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    # or split the code into a wrapper function that creates a boxed
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    # 'param' object then calls another to do the real work.
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    ret = mcgen('''
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%(proto)s
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{
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    QDict *qmp;
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    Error *err = NULL;
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    QMPEventFuncEmit emit;
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''',
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                proto=gen_event_send_proto(name, arg_type))
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    if arg_type and arg_type.members:
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        ret += mcgen('''
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    QmpOutputVisitor *qov;
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    Visitor *v;
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''')
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        ret += gen_param_var(arg_type)
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    ret += mcgen('''
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    emit = qmp_event_get_func_emit();
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    if (!emit) {
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        return;
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    }
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    qmp = qmp_event_build_dict("%(name)s");
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''',
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                 name=name)
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    if arg_type and arg_type.members:
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        ret += mcgen('''
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    qov = qmp_output_visitor_new();
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    v = qmp_output_get_visitor(qov);
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    visit_start_struct(v, "%(name)s", NULL, 0, &err);
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    if (err) {
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        goto out;
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    }
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    visit_type_%(c_name)s_members(v, ¶m, &err);
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    visit_end_struct(v, err ? NULL : &err);
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    if (err) {
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        goto out;
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    }
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    qdict_put_obj(qmp, "data", qmp_output_get_qobject(qov));
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''',
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                     name=name, c_name=arg_type.c_name())
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    ret += mcgen('''
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    emit(%(c_enum)s, qmp, &err);
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''',
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                 c_enum=c_enum_const(event_enum_name, name))
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    if arg_type and arg_type.members:
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        ret += mcgen('''
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out:
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    qmp_output_visitor_cleanup(qov);
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''')
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    ret += mcgen('''
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    error_propagate(errp, err);
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    QDECREF(qmp);
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}
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''')
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    return ret
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class QAPISchemaGenEventVisitor(QAPISchemaVisitor):
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    def __init__(self):
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        self.decl = None
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        self.defn = None
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        self._event_names = None
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    def visit_begin(self, schema):
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        self.decl = ''
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        self.defn = ''
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        self._event_names = []
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    def visit_end(self):
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        self.decl += gen_enum(event_enum_name, self._event_names)
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        self.defn += gen_enum_lookup(event_enum_name, self._event_names)
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        self._event_names = None
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    def visit_event(self, name, info, arg_type):
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        self.decl += gen_event_send_decl(name, arg_type)
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        self.defn += gen_event_send(name, arg_type)
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        self._event_names.append(name)
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(input_file, output_dir, do_c, do_h, prefix, dummy) = parse_command_line()
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c_comment = '''
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/*
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 * schema-defined QAPI event functions
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 *
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 * Copyright (c) 2014 Wenchao Xia
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 *
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 * Authors:
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 *  Wenchao Xia   <wenchaoqemu@gmail.com>
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 *
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 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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 * See the COPYING.LIB file in the top-level directory.
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 *
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 */
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'''
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h_comment = '''
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/*
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 * schema-defined QAPI event functions
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 *
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 * Copyright (c) 2014 Wenchao Xia
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 *
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 * Authors:
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 *  Wenchao Xia  <wenchaoqemu@gmail.com>
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 *
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 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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 * See the COPYING.LIB file in the top-level directory.
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 *
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 */
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'''
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(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
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                            'qapi-event.c', 'qapi-event.h',
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                            c_comment, h_comment)
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fdef.write(mcgen('''
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "%(prefix)sqapi-event.h"
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#include "%(prefix)sqapi-visit.h"
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#include "qapi/qmp-output-visitor.h"
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#include "qapi/qmp-event.h"
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''',
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                 prefix=prefix))
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fdecl.write(mcgen('''
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#include "qapi/error.h"
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#include "qapi/qmp/qdict.h"
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#include "%(prefix)sqapi-types.h"
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''',
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                  prefix=prefix))
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event_enum_name = c_name(prefix + "QAPIEvent", protect=False)
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schema = QAPISchema(input_file)
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gen = QAPISchemaGenEventVisitor()
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schema.visit(gen)
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fdef.write(gen.defn)
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fdecl.write(gen.decl)
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close_output(fdef, fdecl)
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