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, 353 insertions, 0 deletions

diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
new file mode 100644
index 0000000000..3ed78165d7
--- /dev/null
+++ b/scripts/qapi/visit.py
@@ -0,0 +1,353 @@
+"""
+QAPI visitor generator
+
+Copyright IBM, Corp. 2011
+Copyright (C) 2014-2018 Red Hat, Inc.
+
+Authors:
+ Anthony Liguori <aliguori@us.ibm.com>
+ Michael Roth    <mdroth@linux.vnet.ibm.com>
+ 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 *
+
+
+def gen_visit_decl(name, scalar=False):
+    c_type = c_name(name) + ' *'
+    if not scalar:
+        c_type += '*'
+    return mcgen('''
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_type)sobj, Error **errp);
+''',
+                 c_name=c_name(name), c_type=c_type)
+
+
+def gen_visit_members_decl(name):
+    return mcgen('''
+
+void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
+''',
+                 c_name=c_name(name))
+
+
+def gen_visit_object_members(name, base, members, variants):
+    ret = mcgen('''
+
+void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
+{
+    Error *err = NULL;
+
+''',
+                c_name=c_name(name))
+
+    if base:
+        ret += mcgen('''
+    visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, &err);
+    if (err) {
+        goto out;
+    }
+''',
+                     c_type=base.c_name())
+
+    for memb in members:
+        if memb.optional:
+            ret += mcgen('''
+    if (visit_optional(v, "%(name)s", &obj->has_%(c_name)s)) {
+''',
+                         name=memb.name, c_name=c_name(memb.name))
+            push_indent()
+        ret += mcgen('''
+    visit_type_%(c_type)s(v, "%(name)s", &obj->%(c_name)s, &err);
+    if (err) {
+        goto out;
+    }
+''',
+                     c_type=memb.type.c_name(), name=memb.name,
+                     c_name=c_name(memb.name))
+        if memb.optional:
+            pop_indent()
+            ret += mcgen('''
+    }
+''')
+
+    if variants:
+        ret += mcgen('''
+    switch (obj->%(c_name)s) {
+''',
+                     c_name=c_name(variants.tag_member.name))
+
+        for var in variants.variants:
+            ret += mcgen('''
+    case %(case)s:
+        visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, &err);
+        break;
+''',
+                         case=c_enum_const(variants.tag_member.type.name,
+                                           var.name,
+                                           variants.tag_member.type.prefix),
+                         c_type=var.type.c_name(), c_name=c_name(var.name))
+
+        ret += mcgen('''
+    default:
+        abort();
+    }
+''')
+
+    # 'goto out' produced for base, for each member, and if variants were
+    # present
+    if base or members or variants:
+        ret += mcgen('''
+
+out:
+''')
+    ret += mcgen('''
+    error_propagate(errp, err);
+}
+''')
+    return ret
+
+
+def gen_visit_list(name, element_type):
+    return mcgen('''
+
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+{
+    Error *err = NULL;
+    %(c_name)s *tail;
+    size_t size = sizeof(**obj);
+
+    visit_start_list(v, name, (GenericList **)obj, size, &err);
+    if (err) {
+        goto out;
+    }
+
+    for (tail = *obj; tail;
+         tail = (%(c_name)s *)visit_next_list(v, (GenericList *)tail, size)) {
+        visit_type_%(c_elt_type)s(v, NULL, &tail->value, &err);
+        if (err) {
+            break;
+        }
+    }
+
+    if (!err) {
+        visit_check_list(v, &err);
+    }
+    visit_end_list(v, (void **)obj);
+    if (err && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+out:
+    error_propagate(errp, err);
+}
+''',
+                 c_name=c_name(name), c_elt_type=element_type.c_name())
+
+
+def gen_visit_enum(name):
+    return mcgen('''
+
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj, Error **errp)
+{
+    int value = *obj;
+    visit_type_enum(v, name, &value, &%(c_name)s_lookup, errp);
+    *obj = value;
+}
+''',
+                 c_name=c_name(name))
+
+
+def gen_visit_alternate(name, variants):
+    ret = mcgen('''
+
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+{
+    Error *err = NULL;
+
+    visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj),
+                          &err);
+    if (err) {
+        goto out;
+    }
+    if (!*obj) {
+        goto out_obj;
+    }
+    switch ((*obj)->type) {
+''',
+                 c_name=c_name(name))
+
+    for var in variants.variants:
+        ret += mcgen('''
+    case %(case)s:
+''',
+                     case=var.type.alternate_qtype())
+        if isinstance(var.type, QAPISchemaObjectType):
+            ret += mcgen('''
+        visit_start_struct(v, name, NULL, 0, &err);
+        if (err) {
+            break;
+        }
+        visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, &err);
+        if (!err) {
+            visit_check_struct(v, &err);
+        }
+        visit_end_struct(v, NULL);
+''',
+                         c_type=var.type.c_name(),
+                         c_name=c_name(var.name))
+        else:
+            ret += mcgen('''
+        visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, &err);
+''',
+                         c_type=var.type.c_name(),
+                         c_name=c_name(var.name))
+        ret += mcgen('''
+        break;
+''')
+
+    ret += mcgen('''
+    case QTYPE_NONE:
+        abort();
+    default:
+        error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                   "%(name)s");
+    }
+out_obj:
+    visit_end_alternate(v, (void **)obj);
+    if (err && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+out:
+    error_propagate(errp, err);
+}
+''',
+                 name=name, c_name=c_name(name))
+
+    return ret
+
+
+def gen_visit_object(name, base, members, variants):
+    return mcgen('''
+
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+{
+    Error *err = NULL;
+
+    visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), &err);
+    if (err) {
+        goto out;
+    }
+    if (!*obj) {
+        goto out_obj;
+    }
+    visit_type_%(c_name)s_members(v, *obj, &err);
+    if (err) {
+        goto out_obj;
+    }
+    visit_check_struct(v, &err);
+out_obj:
+    visit_end_struct(v, (void **)obj);
+    if (err && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+out:
+    error_propagate(errp, err);
+}
+''',
+                 c_name=c_name(name))
+
+
+class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
+    def __init__(self, opt_builtins):
+        self._opt_builtins = opt_builtins
+        self.decl = None
+        self.defn = None
+        self._btin = None
+
+    def visit_begin(self, schema):
+        self.decl = ''
+        self.defn = ''
+        self._btin = '\n' + guardstart('QAPI_VISIT_BUILTIN')
+
+    def visit_end(self):
+        # To avoid header dependency hell, we always generate
+        # declarations for built-in types in our header files and
+        # simply guard them.  See also opt_builtins (command line
+        # option -b).
+        self._btin += guardend('QAPI_VISIT_BUILTIN')
+        self.decl = self._btin + self.decl
+        self._btin = None
+
+    def visit_enum_type(self, name, info, values, prefix):
+        # Special case for our lone builtin enum type
+        # TODO use something cleaner than existence of info
+        if not info:
+            self._btin += gen_visit_decl(name, scalar=True)
+            if self._opt_builtins:
+                self.defn += gen_visit_enum(name)
+        else:
+            self.decl += gen_visit_decl(name, scalar=True)
+            self.defn += gen_visit_enum(name)
+
+    def visit_array_type(self, name, info, element_type):
+        decl = gen_visit_decl(name)
+        defn = gen_visit_list(name, element_type)
+        if isinstance(element_type, QAPISchemaBuiltinType):
+            self._btin += decl
+            if self._opt_builtins:
+                self.defn += defn
+        else:
+            self.decl += decl
+            self.defn += defn
+
+    def visit_object_type(self, name, info, base, members, variants):
+        # Nothing to do for the special empty builtin
+        if name == 'q_empty':
+            return
+        self.decl += gen_visit_members_decl(name)
+        self.defn += gen_visit_object_members(name, base, members, variants)
+        # TODO Worth changing the visitor signature, so we could
+        # directly use rather than repeat type.is_implicit()?
+        if not name.startswith('q_'):
+            # only explicit types need an allocating visit
+            self.decl += gen_visit_decl(name)
+            self.defn += gen_visit_object(name, base, members, variants)
+
+    def visit_alternate_type(self, name, info, variants):
+        self.decl += gen_visit_decl(name)
+        self.defn += gen_visit_alternate(name, variants)
+
+
+def gen_visit(schema, output_dir, prefix, opt_builtins):
+    blurb = ' * Schema-defined QAPI visitors'
+    genc = QAPIGenC(blurb, __doc__)
+    genh = QAPIGenH(blurb, __doc__)
+
+    genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "%(prefix)sqapi-visit.h"
+''',
+                   prefix=prefix))
+
+    genh.add(mcgen('''
+#include "qapi/visitor.h"
+#include "%(prefix)sqapi-types.h"
+
+''',
+                   prefix=prefix))
+
+    vis = QAPISchemaGenVisitVisitor(opt_builtins)
+    schema.visit(vis)
+    genc.add(vis.defn)
+    genh.add(vis.decl)
+    genc.write(output_dir, prefix + 'qapi-visit.c')
+    genh.write(output_dir, prefix + 'qapi-visit.h')