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, 266 insertions, 0 deletions

diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
new file mode 100644
index 0000000000..aa3c01e750
--- /dev/null
+++ b/scripts/qapi/types.py
@@ -0,0 +1,266 @@
+"""
+QAPI types generator
+
+Copyright IBM, Corp. 2011
+Copyright (c) 2013-2018 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 *
+
+
+# variants must be emitted before their container; track what has already
+# been output
+objects_seen = set()
+
+
+def gen_fwd_object_or_array(name):
+    return mcgen('''
+
+typedef struct %(c_name)s %(c_name)s;
+''',
+                 c_name=c_name(name))
+
+
+def gen_array(name, element_type):
+    return mcgen('''
+
+struct %(c_name)s {
+    %(c_name)s *next;
+    %(c_type)s value;
+};
+''',
+                 c_name=c_name(name), c_type=element_type.c_type())
+
+
+def gen_struct_members(members):
+    ret = ''
+    for memb in members:
+        if memb.optional:
+            ret += mcgen('''
+    bool has_%(c_name)s;
+''',
+                         c_name=c_name(memb.name))
+        ret += mcgen('''
+    %(c_type)s %(c_name)s;
+''',
+                     c_type=memb.type.c_type(), c_name=c_name(memb.name))
+    return ret
+
+
+def gen_object(name, base, members, variants):
+    if name in objects_seen:
+        return ''
+    objects_seen.add(name)
+
+    ret = ''
+    if variants:
+        for v in variants.variants:
+            if isinstance(v.type, QAPISchemaObjectType):
+                ret += gen_object(v.type.name, v.type.base,
+                                  v.type.local_members, v.type.variants)
+
+    ret += mcgen('''
+
+struct %(c_name)s {
+''',
+                 c_name=c_name(name))
+
+    if base:
+        if not base.is_implicit():
+            ret += mcgen('''
+    /* Members inherited from %(c_name)s: */
+''',
+                         c_name=base.c_name())
+        ret += gen_struct_members(base.members)
+        if not base.is_implicit():
+            ret += mcgen('''
+    /* Own members: */
+''')
+    ret += gen_struct_members(members)
+
+    if variants:
+        ret += gen_variants(variants)
+
+    # Make sure that all structs have at least one member; this avoids
+    # potential issues with attempting to malloc space for zero-length
+    # structs in C, and also incompatibility with C++ (where an empty
+    # struct is size 1).
+    if (not base or base.is_empty()) and not members and not variants:
+        ret += mcgen('''
+    char qapi_dummy_for_empty_struct;
+''')
+
+    ret += mcgen('''
+};
+''')
+
+    return ret
+
+
+def gen_upcast(name, base):
+    # C makes const-correctness ugly.  We have to cast away const to let
+    # this function work for both const and non-const obj.
+    return mcgen('''
+
+static inline %(base)s *qapi_%(c_name)s_base(const %(c_name)s *obj)
+{
+    return (%(base)s *)obj;
+}
+''',
+                 c_name=c_name(name), base=base.c_name())
+
+
+def gen_variants(variants):
+    ret = mcgen('''
+    union { /* union tag is @%(c_name)s */
+''',
+                c_name=c_name(variants.tag_member.name))
+
+    for var in variants.variants:
+        ret += mcgen('''
+        %(c_type)s %(c_name)s;
+''',
+                     c_type=var.type.c_unboxed_type(),
+                     c_name=c_name(var.name))
+
+    ret += mcgen('''
+    } u;
+''')
+
+    return ret
+
+
+def gen_type_cleanup_decl(name):
+    ret = mcgen('''
+
+void qapi_free_%(c_name)s(%(c_name)s *obj);
+''',
+                c_name=c_name(name))
+    return ret
+
+
+def gen_type_cleanup(name):
+    ret = mcgen('''
+
+void qapi_free_%(c_name)s(%(c_name)s *obj)
+{
+    Visitor *v;
+
+    if (!obj) {
+        return;
+    }
+
+    v = qapi_dealloc_visitor_new();
+    visit_type_%(c_name)s(v, NULL, &obj, NULL);
+    visit_free(v);
+}
+''',
+                c_name=c_name(name))
+    return ret
+
+
+class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
+    def __init__(self, opt_builtins):
+        self._opt_builtins = opt_builtins
+        self.decl = None
+        self.defn = None
+        self._fwdecl = None
+        self._btin = None
+
+    def visit_begin(self, schema):
+        # gen_object() is recursive, ensure it doesn't visit the empty type
+        objects_seen.add(schema.the_empty_object_type.name)
+        self.decl = ''
+        self.defn = ''
+        self._fwdecl = ''
+        self._btin = '\n' + guardstart('QAPI_TYPES_BUILTIN')
+
+    def visit_end(self):
+        self.decl = self._fwdecl + self.decl
+        self._fwdecl = None
+        # 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_TYPES_BUILTIN')
+        self.decl = self._btin + self.decl
+        self._btin = None
+
+    def _gen_type_cleanup(self, name):
+        self.decl += gen_type_cleanup_decl(name)
+        self.defn += gen_type_cleanup(name)
+
+    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_enum(name, values, prefix)
+            if self._opt_builtins:
+                self.defn += gen_enum_lookup(name, values, prefix)
+        else:
+            self._fwdecl += gen_enum(name, values, prefix)
+            self.defn += gen_enum_lookup(name, values, prefix)
+
+    def visit_array_type(self, name, info, element_type):
+        if isinstance(element_type, QAPISchemaBuiltinType):
+            self._btin += gen_fwd_object_or_array(name)
+            self._btin += gen_array(name, element_type)
+            self._btin += gen_type_cleanup_decl(name)
+            if self._opt_builtins:
+                self.defn += gen_type_cleanup(name)
+        else:
+            self._fwdecl += gen_fwd_object_or_array(name)
+            self.decl += gen_array(name, element_type)
+            self._gen_type_cleanup(name)
+
+    def visit_object_type(self, name, info, base, members, variants):
+        # Nothing to do for the special empty builtin
+        if name == 'q_empty':
+            return
+        self._fwdecl += gen_fwd_object_or_array(name)
+        self.decl += gen_object(name, base, members, variants)
+        if base and not base.is_implicit():
+            self.decl += gen_upcast(name, base)
+        # TODO Worth changing the visitor signature, so we could
+        # directly use rather than repeat type.is_implicit()?
+        if not name.startswith('q_'):
+            # implicit types won't be directly allocated/freed
+            self._gen_type_cleanup(name)
+
+    def visit_alternate_type(self, name, info, variants):
+        self._fwdecl += gen_fwd_object_or_array(name)
+        self.decl += gen_object(name, None, [variants.tag_member], variants)
+        self._gen_type_cleanup(name)
+
+
+def gen_types(schema, output_dir, prefix, opt_builtins):
+    blurb = ' * Schema-defined QAPI types'
+    genc = QAPIGenC(blurb, __doc__)
+    genh = QAPIGenH(blurb, __doc__)
+
+    genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "qapi/dealloc-visitor.h"
+#include "%(prefix)sqapi-types.h"
+#include "%(prefix)sqapi-visit.h"
+''',
+                   prefix=prefix))
+
+    genh.add(mcgen('''
+#include "qapi/util.h"
+'''))
+
+    vis = QAPISchemaGenTypeVisitor(opt_builtins)
+    schema.visit(vis)
+    genc.add(vis.defn)
+    genh.add(vis.decl)
+    genc.write(output_dir, prefix + 'qapi-types.c')
+    genh.write(output_dir, prefix + 'qapi-types.h')