[PATCH spice-common v2] codegen: Define identity macros for enum types

[Frediano Ziglio <fziglio@xxxxxxxxxx>]

An identity macro in C is a macro defined as

  #define SOME_NAME SOME_NAME

They are often used to make possible to use preprocessor to check
for values existence like

  #ifdef SOME_NAME
  ... use SOME_NAME ...
  #endif

Defining these macro for each enumeration value allows to do finer
check in the code that uses spice-protocol.

More specifically you could check a message existence with

  #ifdef SPICE_MSG_MAIN_CHANNELS_LIST
  ... use channels_list message ..
  #endif

or if a given channel exists with

  #ifdef SPICE_CHANNEL_WEBDAV
  ... use WebDAVChannel ...
  #endif

Signed-off-by: Frediano Ziglio <fziglio@xxxxxxxxxx>
---
 python_modules/codegen.py | 10 ++++++++++
 python_modules/ptypes.py  |  2 ++
 spice_codegen.py          |  2 ++
 3 files changed, 14 insertions(+)

Changes since v1:
- better commit message.

diff --git a/python_modules/codegen.py b/python_modules/codegen.py
index f7a2048..6143905 100644
--- a/python_modules/codegen.py
+++ b/python_modules/codegen.py
@@ -327,6 +327,16 @@ class CodeWriter:
     def macro(self, name, args, define):
         self.write("#define %s(%s) %s" % (name, args, define)).newline()
 
+    def identity_macro(self, name):
+        """Define a preprocessor macro with same name as value.
+        This helps writing conditional code using preprocessor defines.
+        """
+        assert(self.at_line_start)
+        indentation = self.indentation
+        self.indentation = 0
+        self.writeln("#define %s %s" % (name, name))
+        self.indentation = indentation
+
     def ifdef(self, name):
         indentation = self.indentation
         self.indentation = 0;
diff --git a/python_modules/ptypes.py b/python_modules/ptypes.py
index 63a7a2f..47b32b5 100644
--- a/python_modules/ptypes.py
+++ b/python_modules/ptypes.py
@@ -381,6 +381,7 @@ class EnumType(EnumBaseType):
                 writer.write(" = %d" % (i))
             writer.write(",")
             writer.newline()
+            writer.identity_macro(self.c_enumname(i))
             current_default = i + 1
         writer.newline()
         writer.write(codegen.prefix_underscore_upper(self.name.upper(), "ENUM_END"))
@@ -434,6 +435,7 @@ class FlagsType(EnumBaseType):
             writer.write(" = (1 << %d)" % (i))
             writer.write(",")
             writer.newline()
+            writer.identity_macro(self.c_enumname(i))
             current_default = i + 1
         writer.newline()
         writer.write(codegen.prefix_underscore_upper(self.name.upper(), "MASK"))
diff --git a/spice_codegen.py b/spice_codegen.py
index 76d7c5e..bb50f31 100755
--- a/spice_codegen.py
+++ b/spice_codegen.py
@@ -40,6 +40,7 @@ def write_channel_enums(writer, channel, client, describe):
             else:
                 writer.writeln("%s = %s," % (enum, m.value))
                 i = m.value + 1
+            writer.identity_macro(enum)
     if describe:
         writer.writeln("{ 0, NULL }");
     else:
@@ -68,6 +69,7 @@ def write_channel_type_enum(writer, describe=False):
             else:
                 writer.writeln("%s = %s," % (enum, c.value))
                 i = c.value + 1
+            writer.identity_macro(enum)
     writer.newline()
     if describe:
         writer.writeln("{ 0, NULL }")
-- 
2.13.6

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