[Qemu-devel] [PATCH RFC 03/21] qapi: New classes QAPIGenC, QAPIGenH, QAPIGenDoc

[Markus Armbruster <armbru@redhat.com>]

These classes encapsulate accumulating and writing output.

Convert C code generation to QAPIGenC and QAPIGenH.  The conversion is
rather shallow: most of the output accumulation is not converted.
Left for later.

The indentation machinery uses a single global variable indent_level,
even though we generally interleave creation of a .c and its .h.  It
should become instance variable of QAPIGenC.  Also left for later.

Documentation generation isn't converted, and QAPIGenDoc isn't used.
This will change shortly.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi-commands.py   | 27 ++++++-------
 scripts/qapi-event.py      | 26 +++++++------
 scripts/qapi-introspect.py | 22 ++++++-----
 scripts/qapi-types.py      | 26 +++++++------
 scripts/qapi-visit.py      | 26 +++++++------
 scripts/qapi.py            | 96 ++++++++++++++++++++++++++--------------------
 6 files changed, 122 insertions(+), 101 deletions(-)

diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index a861ac52e7..4be7dbc482 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -260,12 +260,10 @@ blurb = '''
  * Schema-defined QAPI/QMP commands
 '''
 
-(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
-                            'qmp-marshal.c', 'qmp-commands.h',
-                            blurb, __doc__)
-
-fdef.write(mcgen('''
+genc = QAPIGenC(blurb, __doc__)
+genh = QAPIGenH(blurb, __doc__)
 
+genc.body(mcgen('''
 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "qemu/module.h"
@@ -279,21 +277,24 @@ fdef.write(mcgen('''
 #include "%(prefix)sqmp-commands.h"
 
 ''',
-                 prefix=prefix))
+                prefix=prefix))
 
-fdecl.write(mcgen('''
+genh.body(mcgen('''
 #include "%(prefix)sqapi-types.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/dispatch.h"
 
 void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds);
 ''',
-                  prefix=prefix, c_prefix=c_name(prefix, protect=False)))
+                prefix=prefix, c_prefix=c_name(prefix, protect=False)))
 
 schema = QAPISchema(input_file)
-gen = QAPISchemaGenCommandVisitor()
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
+vis = QAPISchemaGenCommandVisitor()
+schema.visit(vis)
+genc.body(vis.defn)
+genh.body(vis.decl)
 
-close_output(fdef, fdecl)
+if do_c:
+    genc.write(output_dir, prefix + 'qmp-marshal.c')
+if do_h:
+    genh.write(output_dir, prefix + 'qmp-commands.h')
diff --git a/scripts/qapi-event.py b/scripts/qapi-event.py
index b1d611c5ea..da3de17c76 100644
--- a/scripts/qapi-event.py
+++ b/scripts/qapi-event.py
@@ -176,11 +176,10 @@ blurb = '''
  * Schema-defined QAPI/QMP events
 '''
 
-(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
-                            'qapi-event.c', 'qapi-event.h',
-                            blurb, __doc__)
+genc = QAPIGenC(blurb, __doc__)
+genh = QAPIGenH(blurb, __doc__)
 
-fdef.write(mcgen('''
+genc.body(mcgen('''
 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "%(prefix)sqapi-event.h"
@@ -190,22 +189,25 @@ fdef.write(mcgen('''
 #include "qapi/qmp-event.h"
 
 ''',
-                 prefix=prefix))
+                prefix=prefix))
 
-fdecl.write(mcgen('''
+genh.body(mcgen('''
 #include "qapi/util.h"
 #include "qapi/qmp/qdict.h"
 #include "%(prefix)sqapi-types.h"
 
 ''',
-                  prefix=prefix))
+                prefix=prefix))
 
 event_enum_name = c_name(prefix + 'QAPIEvent', protect=False)
 
 schema = QAPISchema(input_file)
-gen = QAPISchemaGenEventVisitor()
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
+vis = QAPISchemaGenEventVisitor()
+schema.visit(vis)
+genc.body(vis.defn)
+genh.body(vis.decl)
 
-close_output(fdef, fdecl)
+if do_c:
+    genc.write(output_dir, prefix + 'qapi-event.c')
+if do_h:
+    genh.write(output_dir, prefix + 'qapi-event.h')
diff --git a/scripts/qapi-introspect.py b/scripts/qapi-introspect.py
index bd9253a172..c654f8fa94 100644
--- a/scripts/qapi-introspect.py
+++ b/scripts/qapi-introspect.py
@@ -181,21 +181,23 @@ blurb = '''
  * QAPI/QMP schema introspection
 '''
 
-(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
-                            'qmp-introspect.c', 'qmp-introspect.h',
-                            blurb, __doc__)
+genc = QAPIGenC(blurb, __doc__)
+genh = QAPIGenH(blurb, __doc__)
 
-fdef.write(mcgen('''
+genc.body(mcgen('''
 #include "qemu/osdep.h"
 #include "%(prefix)sqmp-introspect.h"
 
 ''',
-                 prefix=prefix))
+                prefix=prefix))
 
 schema = QAPISchema(input_file)
-gen = QAPISchemaGenIntrospectVisitor(opt_unmask)
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
+vis = QAPISchemaGenIntrospectVisitor(opt_unmask)
+schema.visit(vis)
+genc.body(vis.defn)
+genh.body(vis.decl)
 
-close_output(fdef, fdecl)
+if do_c:
+    genc.write(output_dir, prefix + 'qmp-introspect.c')
+if do_h:
+    genh.write(output_dir, prefix + 'qmp-introspect.h')
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index 1103dbda2d..97406b3368 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -180,7 +180,7 @@ class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
         self.decl = ''
         self.defn = ''
         self._fwdecl = ''
-        self._btin = guardstart('QAPI_TYPES_BUILTIN')
+        self._btin = '\n' + guardstart('QAPI_TYPES_BUILTIN')
 
     def visit_end(self):
         self.decl = self._fwdecl + self.decl
@@ -256,26 +256,28 @@ blurb = '''
  * Schema-defined QAPI types
 '''
 
-(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
-                            'qapi-types.c', 'qapi-types.h',
-                            blurb, __doc__)
+genc = QAPIGenC(blurb, __doc__)
+genh = QAPIGenH(blurb, __doc__)
 
-fdef.write(mcgen('''
+genc.body(mcgen('''
 #include "qemu/osdep.h"
 #include "qapi/dealloc-visitor.h"
 #include "%(prefix)sqapi-types.h"
 #include "%(prefix)sqapi-visit.h"
 ''',
-                 prefix=prefix))
+                prefix=prefix))
 
-fdecl.write(mcgen('''
+genh.body(mcgen('''
 #include "qapi/util.h"
 '''))
 
 schema = QAPISchema(input_file)
-gen = QAPISchemaGenTypeVisitor()
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
+vis = QAPISchemaGenTypeVisitor()
+schema.visit(vis)
+genc.body(vis.defn)
+genh.body(vis.decl)
 
-close_output(fdef, fdecl)
+if do_c:
+    genc.write(output_dir, prefix + 'qapi-types.c')
+if do_h:
+    genh.write(output_dir, prefix + 'qapi-types.h')
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 5231f89c36..d1b25daf0d 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -339,30 +339,32 @@ blurb = '''
  * Schema-defined QAPI visitors
 '''
 
-(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
-                            'qapi-visit.c', 'qapi-visit.h',
-                            blurb, __doc__)
+genc = QAPIGenC(blurb, __doc__)
+genh = QAPIGenH(blurb, __doc__)
 
-fdef.write(mcgen('''
+genc.body(mcgen('''
 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "qapi/error.h"
 #include "%(prefix)sqapi-visit.h"
 ''',
-                 prefix=prefix))
+                prefix=prefix))
 
-fdecl.write(mcgen('''
+genh.body(mcgen('''
 #include "qapi/visitor.h"
 #include "qapi/qmp/qerror.h"
 #include "%(prefix)sqapi-types.h"
 
 ''',
-                  prefix=prefix))
+                prefix=prefix))
 
 schema = QAPISchema(input_file)
-gen = QAPISchemaGenVisitVisitor()
-schema.visit(gen)
-fdef.write(gen.defn)
-fdecl.write(gen.decl)
+vis = QAPISchemaGenVisitVisitor()
+schema.visit(vis)
+genc.body(vis.defn)
+genh.body(vis.decl)
 
-close_output(fdef, fdecl)
+if do_c:
+    genc.write(output_dir, prefix + 'qapi-visit.c')
+if do_h:
+    genh.write(output_dir, prefix + 'qapi-visit.h')
diff --git a/scripts/qapi.py b/scripts/qapi.py
index d0816f7479..d73ef618e2 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -2,7 +2,7 @@
 # QAPI helper library
 #
 # Copyright IBM, Corp. 2011
-# Copyright (c) 2013-2016 Red Hat Inc.
+# Copyright (c) 2013-2018 Red Hat Inc.
 #
 # Authors:
 #  Anthony Liguori <aliguori@us.ibm.com>
@@ -1820,7 +1820,6 @@ def guardname(filename):
 
 def guardstart(name):
     return mcgen('''
-
 #ifndef %(name)s
 #define %(name)s
 
@@ -1832,7 +1831,6 @@ def guardend(name):
     return mcgen('''
 
 #endif /* %(name)s */
-
 ''',
                  name=guardname(name))
 
@@ -1970,17 +1968,53 @@ def parse_command_line(extra_options='', extra_long_options=[]):
 
     return (fname, output_dir, do_c, do_h, prefix, extra_opts)
 
+
 #
-# Generate output files with boilerplate
+# Accumulate and write output
 #
 
+class QAPIGen(object):
+
+    def __init__(self):
+        self._preamble = ''
+        self._body = ''
+
+    def preamble(self, text):
+        self._preamble += text
+
+    def body(self, text):
+        self._body += text
+
+    def top(self, fname):
+        return ''
+
+    def bottom(self, fname):
+        return ''
+
+    def write(self, output_dir, fname):
+        if output_dir:
+            try:
+                os.makedirs(output_dir)
+            except os.error as e:
+                if e.errno != errno.EEXIST:
+                    raise
+        f = open(os.path.join(output_dir, fname), 'w')
+        f.write(self.top(fname) + self._preamble + self._body
+                + self.bottom(fname))
+        f.close()
+
+
+class QAPIGenC(QAPIGen):
+
+    def __init__(self, blurb, pydoc):
+        QAPIGen.__init__(self)
+        self._blurb = blurb.strip('\n')
+        self._copyright = '\n * '.join(re.findall(r'^Copyright .*', pydoc,
+                                                  re.MULTILINE))
 
-def open_output(output_dir, do_c, do_h, prefix, c_file, h_file, blurb, doc):
-    guard = guardname(prefix + h_file)
-    c_file = output_dir + prefix + c_file
-    h_file = output_dir + prefix + h_file
-    copyright = '\n * '.join(re.findall(r'^Copyright .*', doc, re.MULTILINE))
-    comment = mcgen('''/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
+    def top(self, fname):
+        return mcgen('''
+/* AUTOMATICALLY GENERATED, DO NOT MODIFY */
 
 /*
 %(blurb)s
@@ -1992,41 +2026,19 @@ def open_output(output_dir, do_c, do_h, prefix, c_file, h_file, blurb, doc):
  */
 
 ''',
-                    blurb=blurb.strip('\n'), copyright=copyright)
+                     blurb=self._blurb, copyright=self._copyright)
 
-    if output_dir:
-        try:
-            os.makedirs(output_dir)
-        except os.error as e:
-            if e.errno != errno.EEXIST:
-                raise
 
-    def maybe_open(really, name, opt):
-        if really:
-            return open(name, opt)
-        else:
-            import StringIO
-            return StringIO.StringIO()
+class QAPIGenH(QAPIGenC):
 
-    fdef = maybe_open(do_c, c_file, 'w')
-    fdecl = maybe_open(do_h, h_file, 'w')
+    def top(self, fname):
+        return QAPIGenC.top(self, fname) + guardstart(fname)
 
-    fdef.write(comment)
-    fdecl.write(comment)
-    fdecl.write(mcgen('''
-#ifndef %(guard)s
-#define %(guard)s
+    def bottom(self, fname):
+        return guardend(fname)
 
-''',
-                      guard=guard))
 
-    return (fdef, fdecl)
-
-
-def close_output(fdef, fdecl):
-    fdecl.write(mcgen('''
-
-#endif
-'''))
-    fdecl.close()
-    fdef.close()
+class QAPIGenDoc(QAPIGen):
+    def top(self, fname):
+        return (QAPIGen.top(self, fname)
+                + '@c AUTOMATICALLY GENERATED, DO NOT MODIFY\n\n')
-- 
2.13.6