qapi-gen: New common driver for code and doc generators

Whenever qapi-schema.json changes, we run six programs eleven times to
update eleven files.  Similar for qga/qapi-schema.json.  This is
silly.  Replace the six programs by a single program that spits out
all eleven files.

The programs become modules in new Python package qapi, along with the
helper library.  This requires moving them to scripts/qapi/.  While
moving them, consistently drop executable mode bits.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180211093607.27351-9-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
[eblake: move change to one-line 'blurb' earlier in series, mention mode
bit change as intentional, update qapi-code-gen.txt to match actual
generated events.c file]
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 188 insertions, 0 deletions

diff --git a/scripts/qapi/introspect.py b/scripts/qapi/introspect.py
new file mode 100644
index 0000000000..1e4f065164
--- /dev/null
+++ b/scripts/qapi/introspect.py
@@ -0,0 +1,188 @@
+"""
+QAPI introspection generator
+
+Copyright (C) 2015-2018 Red Hat, Inc.
+
+Authors:
+ Markus Armbruster <armbru@redhat.com>
+
+This work is licensed under the terms of the GNU GPL, version 2.
+See the COPYING file in the top-level directory.
+"""
+
+from qapi.common import *
+
+
+# Caveman's json.dumps() replacement (we're stuck at Python 2.4)
+# TODO try to use json.dumps() once we get unstuck
+def to_json(obj, level=0):
+    if obj is None:
+        ret = 'null'
+    elif isinstance(obj, str):
+        ret = '"' + obj.replace('"', r'\"') + '"'
+    elif isinstance(obj, list):
+        elts = [to_json(elt, level + 1)
+                for elt in obj]
+        ret = '[' + ', '.join(elts) + ']'
+    elif isinstance(obj, dict):
+        elts = ['"%s": %s' % (key.replace('"', r'\"'),
+                              to_json(obj[key], level + 1))
+                for key in sorted(obj.keys())]
+        ret = '{' + ', '.join(elts) + '}'
+    else:
+        assert False                # not implemented
+    if level == 1:
+        ret = '\n' + ret
+    return ret
+
+
+def to_c_string(string):
+    return '"' + string.replace('\\', r'\\').replace('"', r'\"') + '"'
+
+
+class QAPISchemaGenIntrospectVisitor(QAPISchemaVisitor):
+    def __init__(self, prefix, unmask):
+        self._prefix = prefix
+        self._unmask = unmask
+        self.defn = None
+        self.decl = None
+        self._schema = None
+        self._jsons = None
+        self._used_types = None
+        self._name_map = None
+
+    def visit_begin(self, schema):
+        self._schema = schema
+        self._jsons = []
+        self._used_types = []
+        self._name_map = {}
+
+    def visit_end(self):
+        # visit the types that are actually used
+        jsons = self._jsons
+        self._jsons = []
+        for typ in self._used_types:
+            typ.visit(self)
+        # generate C
+        # TODO can generate awfully long lines
+        jsons.extend(self._jsons)
+        name = c_name(self._prefix, protect=False) + 'qmp_schema_json'
+        self.decl = mcgen('''
+extern const char %(c_name)s[];
+''',
+                          c_name=c_name(name))
+        lines = to_json(jsons).split('\n')
+        c_string = '\n    '.join([to_c_string(line) for line in lines])
+        self.defn = mcgen('''
+const char %(c_name)s[] = %(c_string)s;
+''',
+                          c_name=c_name(name),
+                          c_string=c_string)
+        self._schema = None
+        self._jsons = None
+        self._used_types = None
+        self._name_map = None
+
+    def visit_needed(self, entity):
+        # Ignore types on first pass; visit_end() will pick up used types
+        return not isinstance(entity, QAPISchemaType)
+
+    def _name(self, name):
+        if self._unmask:
+            return name
+        if name not in self._name_map:
+            self._name_map[name] = '%d' % len(self._name_map)
+        return self._name_map[name]
+
+    def _use_type(self, typ):
+        # Map the various integer types to plain int
+        if typ.json_type() == 'int':
+            typ = self._schema.lookup_type('int')
+        elif (isinstance(typ, QAPISchemaArrayType) and
+              typ.element_type.json_type() == 'int'):
+            typ = self._schema.lookup_type('intList')
+        # Add type to work queue if new
+        if typ not in self._used_types:
+            self._used_types.append(typ)
+        # Clients should examine commands and events, not types.  Hide
+        # type names to reduce the temptation.  Also saves a few
+        # characters.
+        if isinstance(typ, QAPISchemaBuiltinType):
+            return typ.name
+        if isinstance(typ, QAPISchemaArrayType):
+            return '[' + self._use_type(typ.element_type) + ']'
+        return self._name(typ.name)
+
+    def _gen_json(self, name, mtype, obj):
+        if mtype not in ('command', 'event', 'builtin', 'array'):
+            name = self._name(name)
+        obj['name'] = name
+        obj['meta-type'] = mtype
+        self._jsons.append(obj)
+
+    def _gen_member(self, member):
+        ret = {'name': member.name, 'type': self._use_type(member.type)}
+        if member.optional:
+            ret['default'] = None
+        return ret
+
+    def _gen_variants(self, tag_name, variants):
+        return {'tag': tag_name,
+                'variants': [self._gen_variant(v) for v in variants]}
+
+    def _gen_variant(self, variant):
+        return {'case': variant.name, 'type': self._use_type(variant.type)}
+
+    def visit_builtin_type(self, name, info, json_type):
+        self._gen_json(name, 'builtin', {'json-type': json_type})
+
+    def visit_enum_type(self, name, info, values, prefix):
+        self._gen_json(name, 'enum', {'values': values})
+
+    def visit_array_type(self, name, info, element_type):
+        element = self._use_type(element_type)
+        self._gen_json('[' + element + ']', 'array', {'element-type': element})
+
+    def visit_object_type_flat(self, name, info, members, variants):
+        obj = {'members': [self._gen_member(m) for m in members]}
+        if variants:
+            obj.update(self._gen_variants(variants.tag_member.name,
+                                          variants.variants))
+        self._gen_json(name, 'object', obj)
+
+    def visit_alternate_type(self, name, info, variants):
+        self._gen_json(name, 'alternate',
+                       {'members': [{'type': self._use_type(m.type)}
+                                    for m in variants.variants]})
+
+    def visit_command(self, name, info, arg_type, ret_type,
+                      gen, success_response, boxed):
+        arg_type = arg_type or self._schema.the_empty_object_type
+        ret_type = ret_type or self._schema.the_empty_object_type
+        self._gen_json(name, 'command',
+                       {'arg-type': self._use_type(arg_type),
+                        'ret-type': self._use_type(ret_type)})
+
+    def visit_event(self, name, info, arg_type, boxed):
+        arg_type = arg_type or self._schema.the_empty_object_type
+        self._gen_json(name, 'event', {'arg-type': self._use_type(arg_type)})
+
+
+def gen_introspect(schema, output_dir, prefix, opt_unmask):
+    blurb = ' * QAPI/QMP schema introspection'
+    genc = QAPIGenC(blurb, __doc__)
+    genh = QAPIGenH(blurb, __doc__)
+
+    genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "%(prefix)sqmp-introspect.h"
+
+''',
+                   prefix=prefix))
+
+    vis = QAPISchemaGenIntrospectVisitor(prefix, opt_unmask)
+    schema.visit(vis)
+    genc.add(vis.defn)
+    genh.add(vis.decl)
+    genc.write(output_dir, prefix + 'qmp-introspect.c')
+    genh.write(output_dir, prefix + 'qmp-introspect.h')