[Qemu-devel] [PULL 29/40] qapi: Convert QType into QAPI built-in enum type

[Markus Armbruster <armbru@redhat.com>]

From: Eric Blake <eblake@redhat.com>

What's more meta than using qapi to define qapi? :)

Convert QType into a full-fledged[*] builtin qapi enum type, so
that a subsequent patch can then use it as the discriminator
type of qapi alternate types.  Fortunately, the judicious use of
'prefix' in the qapi definition avoids churn to the spelling of
the enum constants.

To avoid circular definitions, we have to flip the order of
inclusion between "qobject.h" vs. "qapi-types.h".  Back in commit
28770e0, we had the latter include the former, so that we could
use 'QObject *' for our implementation of 'any'.  But that usage
also works with only a forward declaration, whereas the
definition of QObject requires QType to be a complete type.

[*] The type has to be builtin, rather than declared in
qapi/common.json, because we want to use it for alternates even
when common.json is not included. But since it is the first
builtin enum type, we have to add special cases to qapi-types
and qapi-visit to only emit definitions once, even when two
qapi files are being compiled into the same binary (the way we
already handled builtin list types like 'intList').  We may
need to revisit how multiple qapi files share common types,
but that's a project for another day.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1449033659-25497-4-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 docs/qapi-code-gen.txt                   |  1 +
 include/qapi/qmp/qobject.h               | 21 +++++----------------
 include/qemu/typedefs.h                  |  1 +
 qobject/qobject.c                        |  4 ++--
 scripts/qapi-types.py                    | 16 ++++++++++++----
 scripts/qapi-visit.py                    | 11 +++++++++--
 scripts/qapi.py                          |  6 ++++++
 tests/qapi-schema/alternate-empty.out    |  2 ++
 tests/qapi-schema/comments.out           |  2 ++
 tests/qapi-schema/empty.out              |  2 ++
 tests/qapi-schema/event-case.out         |  2 ++
 tests/qapi-schema/flat-union-empty.out   |  2 ++
 tests/qapi-schema/ident-with-escape.out  |  2 ++
 tests/qapi-schema/include-relpath.out    |  2 ++
 tests/qapi-schema/include-repetition.out |  2 ++
 tests/qapi-schema/include-simple.out     |  2 ++
 tests/qapi-schema/indented-expr.out      |  2 ++
 tests/qapi-schema/qapi-schema-test.out   |  2 ++
 tests/qapi-schema/union-clash-data.out   |  2 ++
 tests/qapi-schema/union-empty.out        |  2 ++
 20 files changed, 62 insertions(+), 24 deletions(-)

diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index 2becba9..79bf072 100644
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -160,6 +160,7 @@ The following types are predefined, and map to C as follows:
                        accepts size suffixes
   bool      bool       JSON true or false
   any       QObject *  any JSON value
+  QType     QType      JSON string matching enum QType values
 
 
 === Includes ===
diff --git a/include/qapi/qmp/qobject.h b/include/qapi/qmp/qobject.h
index c0f1e99..74459ae 100644
--- a/include/qapi/qmp/qobject.h
+++ b/include/qapi/qmp/qobject.h
@@ -34,23 +34,12 @@
 
 #include <stddef.h>
 #include <assert.h>
+#include "qapi-types.h"
 
-typedef enum {
-    QTYPE_NONE,    /* sentinel value, no QObject has this type code */
-    QTYPE_QNULL,
-    QTYPE_QINT,
-    QTYPE_QSTRING,
-    QTYPE_QDICT,
-    QTYPE_QLIST,
-    QTYPE_QFLOAT,
-    QTYPE_QBOOL,
-    QTYPE_MAX,
-} QType;
-
-typedef struct QObject {
+struct QObject {
     QType type;
     size_t refcnt;
-} QObject;
+};
 
 /* Get the 'base' part of an object */
 #define QOBJECT(obj) (&(obj)->base)
@@ -66,7 +55,7 @@ typedef struct QObject {
 /* Initialize an object to default values */
 static inline void qobject_init(QObject *obj, QType type)
 {
-    assert(QTYPE_NONE < type && type < QTYPE_MAX);
+    assert(QTYPE_NONE < type && type < QTYPE__MAX);
     obj->refcnt = 1;
     obj->type = type;
 }
@@ -102,7 +91,7 @@ static inline void qobject_decref(QObject *obj)
  */
 static inline QType qobject_type(const QObject *obj)
 {
-    assert(QTYPE_NONE < obj->type && obj->type < QTYPE_MAX);
+    assert(QTYPE_NONE < obj->type && obj->type < QTYPE__MAX);
     return obj->type;
 }
 
diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
index 3eedcf4..78fe6e8 100644
--- a/include/qemu/typedefs.h
+++ b/include/qemu/typedefs.h
@@ -80,6 +80,7 @@ typedef struct QEMUSGList QEMUSGList;
 typedef struct QEMUSizedBuffer QEMUSizedBuffer;
 typedef struct QEMUTimer QEMUTimer;
 typedef struct QEMUTimerListGroup QEMUTimerListGroup;
+typedef struct QObject QObject;
 typedef struct RAMBlock RAMBlock;
 typedef struct Range Range;
 typedef struct SerialState SerialState;
diff --git a/qobject/qobject.c b/qobject/qobject.c
index 1df315a..a3ef14e 100644
--- a/qobject/qobject.c
+++ b/qobject/qobject.c
@@ -15,7 +15,7 @@
 #include "qapi/qmp/qlist.h"
 #include "qapi/qmp/qstring.h"
 
-static void (*qdestroy[QTYPE_MAX])(QObject *) = {
+static void (*qdestroy[QTYPE__MAX])(QObject *) = {
     [QTYPE_NONE] = NULL,               /* No such object exists */
     [QTYPE_QNULL] = NULL,              /* qnull_ is indestructible */
     [QTYPE_QINT] = qint_destroy_obj,
@@ -29,6 +29,6 @@ static void (*qdestroy[QTYPE_MAX])(QObject *) = {
 void qobject_destroy(QObject *obj)
 {
     assert(!obj->refcnt);
-    assert(QTYPE_QNULL < obj->type && obj->type < QTYPE_MAX);
+    assert(QTYPE_QNULL < obj->type && obj->type < QTYPE__MAX);
     qdestroy[obj->type](obj);
 }
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index 2f2f7df..2071846 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -112,7 +112,7 @@ extern const int %(c_name)s_qtypes[];
 def gen_alternate_qtypes(name, variants):
     ret = mcgen('''
 
-const int %(c_name)s_qtypes[QTYPE_MAX] = {
+const int %(c_name)s_qtypes[QTYPE__MAX] = {
 ''',
                 c_name=c_name(name))
 
@@ -233,8 +233,15 @@ class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
         self.defn += gen_type_cleanup(name)
 
     def visit_enum_type(self, name, info, values, prefix):
-        self._fwdecl += gen_enum(name, values, prefix)
-        self._fwdefn += gen_enum_lookup(name, 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 do_builtins:
+                self.defn += gen_enum_lookup(name, values, prefix)
+        else:
+            self._fwdecl += gen_enum(name, values, prefix)
+            self._fwdefn += gen_enum_lookup(name, values, prefix)
 
     def visit_array_type(self, name, info, element_type):
         if isinstance(element_type, QAPISchemaBuiltinType):
@@ -316,10 +323,11 @@ fdef.write(mcgen('''
 ''',
                  prefix=prefix))
 
+# To avoid circular headers, use only typedefs.h here, not qobject.h
 fdecl.write(mcgen('''
 #include <stdbool.h>
 #include <stdint.h>
-#include "qapi/qmp/qobject.h"
+#include "qemu/typedefs.h"
 '''))
 
 schema = QAPISchema(input_file)
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 94cd113..7ceda18 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -347,8 +347,15 @@ class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
                     isinstance(entity, QAPISchemaObjectType))
 
     def visit_enum_type(self, name, info, values, prefix):
-        self.decl += gen_visit_decl(name, scalar=True)
-        self.defn += gen_visit_enum(name)
+        # 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 do_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)
diff --git a/scripts/qapi.py b/scripts/qapi.py
index b336fbd..c9e4ad2 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -34,6 +34,7 @@ builtin_types = {
     'uint64':   'QTYPE_QINT',
     'size':     'QTYPE_QINT',
     'any':      None,           # any QType possible, actually
+    'QType':    'QTYPE_QSTRING',
 }
 
 # Whitelist of commands allowed to return a non-dictionary
@@ -1244,6 +1245,11 @@ class QAPISchema(object):
         self.the_empty_object_type = QAPISchemaObjectType(':empty', None, None,
                                                           [], None)
         self._def_entity(self.the_empty_object_type)
+        self._def_entity(QAPISchemaEnumType('QType', None,
+                                            ['none', 'qnull', 'qint',
+                                             'qstring', 'qdict', 'qlist',
+                                             'qfloat', 'qbool'],
+                                            'QTYPE'))
 
     def _make_implicit_enum_type(self, name, info, values):
         name = name + 'Kind'   # Use namespace reserved by add_name()
diff --git a/tests/qapi-schema/alternate-empty.out b/tests/qapi-schema/alternate-empty.out
index 0f153b6..02b9876 100644
--- a/tests/qapi-schema/alternate-empty.out
+++ b/tests/qapi-schema/alternate-empty.out
@@ -2,3 +2,5 @@ object :empty
 alternate Alt
     case i: int
 enum AltKind ['i']
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
diff --git a/tests/qapi-schema/comments.out b/tests/qapi-schema/comments.out
index 9e2c656..97be601 100644
--- a/tests/qapi-schema/comments.out
+++ b/tests/qapi-schema/comments.out
@@ -1,2 +1,4 @@
 object :empty
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 enum Status ['good', 'bad', 'ugly']
diff --git a/tests/qapi-schema/empty.out b/tests/qapi-schema/empty.out
index 272b161..6522940 100644
--- a/tests/qapi-schema/empty.out
+++ b/tests/qapi-schema/empty.out
@@ -1 +1,3 @@
 object :empty
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
diff --git a/tests/qapi-schema/event-case.out b/tests/qapi-schema/event-case.out
index cdfd264..6350d64 100644
--- a/tests/qapi-schema/event-case.out
+++ b/tests/qapi-schema/event-case.out
@@ -1,2 +1,4 @@
 object :empty
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 event oops None
diff --git a/tests/qapi-schema/flat-union-empty.out b/tests/qapi-schema/flat-union-empty.out
index 0e0665a..eade2d5 100644
--- a/tests/qapi-schema/flat-union-empty.out
+++ b/tests/qapi-schema/flat-union-empty.out
@@ -2,6 +2,8 @@ object :empty
 object Base
     member type: Empty optional=False
 enum Empty []
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 object Union
     base Base
     tag type
diff --git a/tests/qapi-schema/ident-with-escape.out b/tests/qapi-schema/ident-with-escape.out
index f4542b1..453e0b2 100644
--- a/tests/qapi-schema/ident-with-escape.out
+++ b/tests/qapi-schema/ident-with-escape.out
@@ -1,5 +1,7 @@
 object :empty
 object :obj-fooA-arg
     member bar1: str optional=False
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 command fooA :obj-fooA-arg -> None
    gen=True success_response=True
diff --git a/tests/qapi-schema/include-relpath.out b/tests/qapi-schema/include-relpath.out
index 9e2c656..97be601 100644
--- a/tests/qapi-schema/include-relpath.out
+++ b/tests/qapi-schema/include-relpath.out
@@ -1,2 +1,4 @@
 object :empty
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 enum Status ['good', 'bad', 'ugly']
diff --git a/tests/qapi-schema/include-repetition.out b/tests/qapi-schema/include-repetition.out
index 9e2c656..97be601 100644
--- a/tests/qapi-schema/include-repetition.out
+++ b/tests/qapi-schema/include-repetition.out
@@ -1,2 +1,4 @@
 object :empty
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 enum Status ['good', 'bad', 'ugly']
diff --git a/tests/qapi-schema/include-simple.out b/tests/qapi-schema/include-simple.out
index 9e2c656..97be601 100644
--- a/tests/qapi-schema/include-simple.out
+++ b/tests/qapi-schema/include-simple.out
@@ -1,2 +1,4 @@
 object :empty
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 enum Status ['good', 'bad', 'ugly']
diff --git a/tests/qapi-schema/indented-expr.out b/tests/qapi-schema/indented-expr.out
index 226d300..ce37ff5 100644
--- a/tests/qapi-schema/indented-expr.out
+++ b/tests/qapi-schema/indented-expr.out
@@ -1,4 +1,6 @@
 object :empty
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 command eins None -> None
    gen=True success_response=True
 command zwei None -> None
diff --git a/tests/qapi-schema/qapi-schema-test.out b/tests/qapi-schema/qapi-schema-test.out
index 0724a9f..b87cfba 100644
--- a/tests/qapi-schema/qapi-schema-test.out
+++ b/tests/qapi-schema/qapi-schema-test.out
@@ -101,6 +101,8 @@ object NestedEnumsOne
     member enum4: EnumOne optional=True
 enum QEnumTwo ['value1', 'value2']
     prefix QENUM_TWO
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 object TestStruct
     member integer: int optional=False
     member boolean: bool optional=False
diff --git a/tests/qapi-schema/union-clash-data.out b/tests/qapi-schema/union-clash-data.out
index cea8551..f5752f4 100644
--- a/tests/qapi-schema/union-clash-data.out
+++ b/tests/qapi-schema/union-clash-data.out
@@ -1,6 +1,8 @@
 object :empty
 object :obj-int-wrapper
     member data: int optional=False
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 object TestUnion
     member type: TestUnionKind optional=False
     case data: :obj-int-wrapper
diff --git a/tests/qapi-schema/union-empty.out b/tests/qapi-schema/union-empty.out
index 9c89fd1..bdf17e5 100644
--- a/tests/qapi-schema/union-empty.out
+++ b/tests/qapi-schema/union-empty.out
@@ -1,4 +1,6 @@
 object :empty
+enum QType ['none', 'qnull', 'qint', 'qstring', 'qdict', 'qlist', 'qfloat', 'qbool']
+    prefix QTYPE
 object Union
     member type: UnionKind optional=False
 enum UnionKind []
-- 
2.4.3