Pepper IDL: Check for structs in callbacks.

ppapi/generators/idl_c_header.py

Index: ppapi/generators/idl_c_header.py
diff --git a/ppapi/generators/idl_c_header.py b/ppapi/generators/idl_c_header.py
index 2c3cf2cb3a2755a3d14e78ad4c7033449255de79..eab18c57ed2a72854b60afd3fcb76bb2e3484081 100755
--- a/ppapi/generators/idl_c_header.py
+++ b/ppapi/generators/idl_c_header.py
@@ -139,11 +139,42 @@ def GenerateHeader(out, filenode, releases):
     out.Write(CommentLines(['*',' @}', '']) + '\n')
 
 
+def CheckTypedefs(filenode, releases):
+  """Checks that typedefs don't specify callbacks that take some structs.
+
+  See http://crbug.com/233439 for details.
+  """
+  cgen = CGen()
+  # TODO(teravest): Allow PP_Var structs to be passed as callback parameters.

[Mark Seaborn, 2013/04/23 15:08:47]

We don't want to allow PP_Var to be passed by value in typedef'd callbacks. 
Maybe write "Fix the following callback to pass PP_Var by pointer rather than by
value".

+  node_whitelist = ('PP_Ext_Alarms_OnAlarm_Func_Dev_0_1',)

[Mark Seaborn, 2013/04/23 15:08:47]

Nit: '[]' lists are a little neater than '(,)' tuples for variable-length lists
since there's no odd trailing comma in the singleton case.

+  for node in filenode.GetListOf('Typedef'):
+    if node.GetName() in node_whitelist:
+      continue
+    build_list = node.GetUniqueReleases(releases)
+    callnode = node.GetOneOf('Callspec')
+    if callnode:
+      for param in callnode.GetListOf('Param'):
+        if param.GetListOf('Array'):
+          continue
+        if cgen.GetParamMode(param) != 'in':
+          continue
+        t = param.GetType(build_list[0])
+        if t.IsA('Struct'):

[Mark Seaborn, 2013/04/23 15:08:47]

How about:

while t.IsA('Typedef'):
  t = t.GetType(build_list[0])

I don't know if you need to handle multiple levels of typedefs, but this at
least means you don't have to duplicate the struct check + error message.

+          raise Exception('%s is a struct in callback %s. '
+                          'See http://crbug.com/233439' %
+                          (t.GetName(), node.GetName()))
+        elif t.IsA('Typedef'):
+          if t.GetType(build_list[0]).IsA('Struct'):
+            raise Exception('%s is a struct in callback %s. '
+                            'See http://crbug.com/233439' %
+                            (t.GetName(), node.GetName()))
+
 class HGen(GeneratorByFile):
   def __init__(self):
     Generator.__init__(self, 'C Header', 'cgen', 'Generate the C headers.')
 
   def GenerateFile(self, filenode, releases, options):
+    CheckTypedefs(filenode, releases)
     savename = GetHeaderFromNode(filenode, GetOption('dstroot'))
     my_min, my_max = filenode.GetMinMax(releases)
     if my_min > releases[-1] or my_max < releases[0]: