Force 8-byte alignment in PP_InputEvent. Rev PPP_Instance interface to 0.3 because this changes the size of PP_InputEvent on Linux x86-32. Add an assertion for the size of PP_InputEvent.

Note I had to tweak the macro to allow for a typename of "struct PP_InputEvent", because I was relying on having no spaces in the typename.  Now there's a separate macro for structs.  Other options would include:
- adding a typedef, e.g. PP_InputEvent_t, and using that in the original macro (this was my initial approach, but I decided I'd rather make a new macro than obfuscate the PP_InputEvent declaration)
- Make PP_InputEvent itself a typedef, i.e. typedef struct {...} PP_InputEvent.  This would make it impossible to forward-declare PP_InputEvent, and would require code changes elsewhere.
- Change the macro some other way so that we don't need 2 macros (e.g., don't use the passed typename when creating a unique name).  Use another trick like using the line number.  This also has the drawback of making the error message less helpful.

BUG=62983
TEST=NaCl tests/ppapi_proxy/event_example (see http://codereview.chromium.org/3767003/show)

Review URL: http://codereview.chromium.org/4861002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@66000 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 40 insertions, 4 deletions

diff --git a/ppapi/c/pp_input_event.h b/ppapi/c/pp_input_event.h
index 715c016..7f95e09 100644
--- a/ppapi/c/pp_input_event.h
+++ b/ppapi/c/pp_input_event.h
@@ -14,6 +14,7 @@
  */
 
 #include "ppapi/c/pp_bool.h"
+#include "ppapi/c/pp_macros.h"
 #include "ppapi/c/pp_stdint.h"
 #include "ppapi/c/pp_time.h"
 
@@ -149,6 +150,10 @@ struct PP_InputEvent_Wheel {
   PP_Bool scroll_by_page;
 };
 
+/* Ensure the elements of the struct (especially the time_stamp) are aligned on
+   8-byte boundaries, since some compilers align doubles on 8-byte boundaries
+   for 32-bit x86, and some align on 4-byte boundaries. */
+#pragma pack(push, 8)
 struct PP_InputEvent {
   /** Identifies the type of the event. */
   PP_InputEvent_Type type;
@@ -173,6 +178,10 @@ struct PP_InputEvent {
     char padding[64];
   } u;
 };
+#pragma pack(pop)
+/* TODO(dmichael):  Figure out why the input event is not 80 bytes wide on Mac.
+PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_InputEvent, 80);
+ */
 
 /**
  * @}
diff --git a/ppapi/c/pp_macros.h b/ppapi/c/pp_macros.h
index ffc48b0..a46ea2e 100644
--- a/ppapi/c/pp_macros.h
+++ b/ppapi/c/pp_macros.h
@@ -42,12 +42,39 @@
    (which should always be valid) if the enum's size is SIZE, and otherwise the
    size of the array will be -1 (which all/most compilers should flag as an
    error).  This is wrapped inside a struct, because if it is a simple global
-   we get multiple definition errors at link time. */
-#define PP_COMPILE_ASSERT_SIZE_IN_BYTES(NAME, SIZE) \
+   we get multiple definition errors at link time.
+
+   NAME is the name of the type without any spaces or the struct or enum
+   keywords.
+
+   CTYPENAME is the typename required by C.  I.e., for a struct or enum, the
+   appropriate keyword must be included.
+
+   SIZE is the expected size in bytes.
+ */
+#define PP_COMPILE_ASSERT_SIZE_IN_BYTES_IMPL(NAME, CTYPENAME, SIZE) \
 struct _dummy_struct_for_##NAME { \
 char _COMPILE_ASSERT_FAILED_The_type_named_ \
 ## NAME ## _is_not_ ## SIZE ## \
-_bytes_wide[(sizeof(NAME) == SIZE) ? 1 : -1]; }
+_bytes_wide[(sizeof(CTYPENAME) == SIZE) ? 1 : -1]; }
+
+/* PP_COMPILE_ASSERT_SIZE_IN_BYTES is for typenames that contain no spaces.
+   E.g.:
+   PP_COMPILE_ASSERT_SIZE_IN_BYTES(int, 4);
+   typedef struct { int a; } Foo;
+   PP_COMPILE_ASSERT_SIZE_IN_BYTES(Foo, 4);
+ */
+#define PP_COMPILE_ASSERT_SIZE_IN_BYTES(NAME, SIZE) \
+PP_COMPILE_ASSERT_SIZE_IN_BYTES_IMPL(NAME, NAME, SIZE)
+
+/* PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES is for typenames that contain 'struct'
+   in C.  That is, struct names that are not typedefs.
+   E.g.:
+   struct Foo { int a; };
+   PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(Foo, 4);
+ */
+#define PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(NAME, SIZE) \
+PP_COMPILE_ASSERT_SIZE_IN_BYTES_IMPL(NAME, struct NAME, SIZE)
 
 /**
  * @}
diff --git a/ppapi/c/ppp_instance.h b/ppapi/c/ppp_instance.h
index cb7988d..19907ca 100644
--- a/ppapi/c/ppp_instance.h
+++ b/ppapi/c/ppp_instance.h
@@ -13,7 +13,7 @@
 struct PP_InputEvent;
 struct PP_Var;
 
-#define PPP_INSTANCE_INTERFACE "PPP_Instance;0.2"
+#define PPP_INSTANCE_INTERFACE "PPP_Instance;0.3"
 
 /**
  * @file