From 3b345f3e2d7870ce23a14e1c11217dbd7aa62d8e Mon Sep 17 00:00:00 2001
From: Niels Provos <provos@gmail.com>
Date: Wed, 12 Dec 2007 07:02:55 +0000
Subject: [PATCH] pull setters/getters out of RPC structures to reduce their
 memory footprint

svn:r585
---
 ChangeLog       |  1 +
 event_rpcgen.py | 46 ++++++++++++++++++++++++++--------------------
 2 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b8d895d6..32635065 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -22,6 +22,7 @@ Changes in current version:
  o Rewrite win32.c backend to be O(n lg n) rather than O(n^2).
  o Removed obsoleted recalc code
  o support for 32-bit tag numbers in rpc structures; this is wire compatible, but changes the API slightly.
+ o pull setters/getters out of RPC structures into a base class to which we just need to store a pointer; this reduces the memory footprint of these structures.
    
 
 Changes in 1.4.0:
diff --git a/event_rpcgen.py b/event_rpcgen.py
index 3489dc7a..1ff55e73 100755
--- a/event_rpcgen.py
+++ b/event_rpcgen.py
@@ -69,17 +69,22 @@ class Struct:
 
     def PrintDeclaration(self, file):
         print >>file, '/* Structure declaration for %s */' % self._name
-        print >>file, 'struct %s {' % self._name
+        print >>file, 'struct %s_access_ {' % self._name
         for entry in self._entries:
-            dcl = entry.Declaration()
-            dcl.extend(
-                entry.AssignDeclaration('(*%s_assign)' % entry.Name()))
+            dcl = entry.AssignDeclaration('(*%s_assign)' % entry.Name())
             dcl.extend(
                 entry.GetDeclaration('(*%s_get)' % entry.Name()))
             if entry.Array():
                 dcl.extend(
                     entry.AddDeclaration('(*%s_add)' % entry.Name()))
             self.PrintIdented(file, '  ', dcl)
+        print >>file, '};\n'
+
+        print >>file, 'struct %s {' % self._name
+        print >>file, '  struct %s_access_ *base;\n' % self._name
+        for entry in self._entries:
+            dcl = entry.Declaration()
+            self.PrintIdented(file, '  ', dcl)
         print >>file, ''
         for entry in self._entries:
             print >>file, '  uint8_t %s_set;' % entry.Name()
@@ -115,6 +120,13 @@ int evtag_unmarshal_%(name)s(struct evbuffer *, uint32_t,
                        ' * Implementation of %s\n'
                        ' */\n') % self._name
 
+        print >>file, \
+              'static struct %(name)s_access_ __%(name)s_base = {' % \
+              { 'name' : self._name }
+        for entry in self._entries:
+            self.PrintIdented(file, '  ', entry.CodeBase())
+        print >>file, '};\n'
+
         # Creation
         print >>file, (
             'struct %(name)s *\n'
@@ -124,7 +136,8 @@ int evtag_unmarshal_%(name)s(struct evbuffer *, uint32_t,
             '  if ((tmp = malloc(sizeof(struct %(name)s))) == NULL) {\n'
             '    event_warn("%%s: malloc", __func__);\n'
             '    return (NULL);\n'
-            '  }') % { 'name' : self._name }
+            '  }\n'
+            '  tmp->base = &__%(name)s_base;\n') % { 'name' : self._name }
 
         for entry in self._entries:
             self.PrintIdented(file, '  ', entry.CodeNew('tmp'))
@@ -398,19 +411,16 @@ class Entry:
     def CodeFree(self, name):
         return []
 
-    def CodeNew(self, name):
+    def CodeBase(self):
         code = [
-            '%(vname)s->%(name)s_assign = %(parent_name)s_%(name)s_assign;',
-            '%(vname)s->%(name)s_get = %(parent_name)s_%(name)s_get;'
+            '%(parent_name)s_%(name)s_assign,',
+            '%(parent_name)s_%(name)s_get,'
             ]
         if self.Array():
-            code.append(
-                '%(vname)s->%(name)s_add = %(parent_name)s_%(name)s_add;')
+            code.append('%(parent_name)s_%(name)s_add,')
 
         code = '\n'.join(code)
-        trans = self.GetTranslation()
-        trans['vname'] = name
-        code = code % trans
+        code = code % self.GetTranslation()
         return code.split('\n')
 
     def Verify(self):
@@ -595,7 +605,6 @@ class EntryString(Entry):
         
     def CodeNew(self, name):
         code  = ['%s->%s_data = NULL;' % (name, self._name)]
-        code.extend(Entry.CodeNew(self, name))
         return code
 
     def CodeFree(self, name):
@@ -721,7 +730,6 @@ class EntryStruct(Entry):
         
     def CodeNew(self, name):
         code  = ['%s->%s_data = NULL;' % (name, self._name)]
-        code.extend(Entry.CodeNew(self, name))
         return code
 
     def CodeFree(self, name):
@@ -828,7 +836,6 @@ class EntryVarBytes(Entry):
     def CodeNew(self, name):
         code  = ['%s->%s_data = NULL;' % (name, self._name),
                  '%s->%s_length = 0;' % (name, self._name) ]
-        code.extend(Entry.CodeNew(self, name))
         return code
 
     def CodeFree(self, name):
@@ -1011,7 +1018,6 @@ if (evtag_unmarshal_%(refname)s(%(buf)s, %(tag_name)s,
         code  = ['%s->%s_data = NULL;' % (name, self._name),
                  '%s->%s_length = 0;' % (name, self._name),
                  '%s->%s_num_allocated = 0;' % (name, self._name)]
-        code.extend(Entry.CodeNew(self, name))
         return code
 
     def CodeFree(self, name):
@@ -1306,10 +1312,10 @@ def HeaderPreamble(name):
     pre += (
         '#define EVTAG_HAS(msg, member) ((msg)->member##_set == 1)\n'
         '#define EVTAG_ASSIGN(msg, member, args...) '
-        '(*(msg)->member##_assign)(msg, ## args)\n'
+        '(*(msg)->base->member##_assign)(msg, ## args)\n'
         '#define EVTAG_GET(msg, member, args...) '
-        '(*(msg)->member##_get)(msg, ## args)\n'
-        '#define EVTAG_ADD(msg, member) (*(msg)->member##_add)(msg)\n'
+        '(*(msg)->base->member##_get)(msg, ## args)\n'
+        '#define EVTAG_ADD(msg, member) (*(msg)->base->member##_add)(msg)\n'
         '#define EVTAG_LEN(msg, member) ((msg)->member##_length)\n'
         )