Revise gamepad interface

Per API review, revision to gamepad interface. Still in _dev for now, will move to stable as separate change once we're happy with the interface.

Change summary:
- renames of various fields, and main function in idl per discussion
- timestamp to double, connected to PP_Bool
- remove #pragma pack in header, now copied member-by-member
- update examples

One complication was in removing the #pragma pack. Copying by member in webkit/plugins/ppapi/ppapi_plugin_instance.cc avoids the need to keep webkit and pepper in sync and exactly the same layout (a good thing).

However, when the native_client ppapi proxy is going between 32 and 64 the data structure ends up being a different size due to padding (all the fields are teh same sizes though). To workaround this, I added padding fields, and assert_sizes to confirm the sizes are the same on both "sides". This is similar to how PP_Point, input events, etc. get rpc'd, but perhaps there's a better way.

BUG=112879

Review URL: http://codereview.chromium.org/9405033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@124375 0039d316-1c4b-4281-b951-d872f2087c98

10 files changed, 101 insertions, 99 deletions

diff --git a/ppapi/api/dev/ppb_gamepad_dev.idl b/ppapi/api/dev/ppb_gamepad_dev.idl
index 8e6a4a9..a9b5918 100644
--- a/ppapi/api/dev/ppb_gamepad_dev.idl
+++ b/ppapi/api/dev/ppb_gamepad_dev.idl
@@ -9,87 +9,87 @@
  */
 
 label Chrome {
-  M18 = 0.1
+  M19 = 0.2
 };
 
-#inline c
-#pragma pack(push, 1)
-#endinl
-
 /**
  * The data for one gamepad device.
  */
-struct PP_GamepadData_Dev {
+[assert_size(472)]
+struct PP_GamepadSampleData_Dev {
     /**
-     * Is there a gamepad connected at this index? If this is false, no other
-     * data in this structure is valid.
+     * Number of valid elements in the |axes| array.
      */
-    char connected;
+    uint32_t axes_length;
 
     /**
-     * String identifier for the type of device/manufacturer.
+     * Normalized values for the axes, indices valid up to |axes_length|-1. Axis
+     * values range from -1..1, and are in order of "importance".
      */
-    uint16_t[128] id;
+    float_t[16] axes;
 
     /**
-     * Monotonically increasing value that is incremented when the data have
-     * been updated.
+     * Number of valid elements in the |buttons| array.
      */
-    uint64_t timestamp;
+    uint32_t buttons_length;
 
     /**
-     * Number of valid elements in the |axes| array.
+     * Normalized values for the buttons, indices valid up to |buttons_length|
+     * - 1. Button values range from 0..1, and are in order of importance.
      */
-    uint32_t axes_length;
+    float_t[32] buttons;
 
     /**
-     * Normalized values for the axes, indices valid up to |axesLength|-1. Axis
-     * values range from -1..1, and are in order of "importance".
+     * Monotonically increasing value that is incremented when the data have
+     * been updated.
      */
-    float_t[16] axes;
+    double_t timestamp;
 
     /**
-     * Number of valid elements in the |buttons| array.
+     * Identifier for the type of device/manufacturer.
      */
-    uint32_t buttons_length;
+    uint16_t[128] id;
 
     /**
-     * Normalized values for the buttons, indices valid up to |buttonsLength|
-     * - 1. Button values range from 0..1, and are in order of importance.
+     * Is there a gamepad connected at this index? If this is false, no other
+     * data in this structure is valid.
      */
-    float_t[32] buttons;
+    PP_Bool connected;
+
+    /* Padding to make the struct the same size between 64 and 32. */
+    char[4] unused_pad_;
 };
 
 /**
  * The data for all gamepads connected to the system.
  */
-struct PP_GamepadsData_Dev {
+[assert_size(1896)]
+struct PP_GamepadsSampleData_Dev {
     /**
      * Number of valid elements in the |items| array.
      */
     uint32_t length;
 
+    /* Padding to make the struct the same size between 64 and 32. */
+    char[4] unused_pad_;
+
     /**
      * Data for an individual gamepad device connected to the system.
      */
-    PP_GamepadData_Dev[4] items;
+    PP_GamepadSampleData_Dev[4] items;
 };
 
-#inline c
-#pragma pack(pop)
-#endinl
-
 /**
  * The <code>PPB_Gamepad_Dev</code> interface allows retrieving data from
  * gamepad/joystick devices that are connected to the system.
  */
-[version=0.1, macro="PPB_GAMEPAD_DEV_INTERFACE"]
+[version=0.2, macro="PPB_GAMEPAD_DEV_INTERFACE"]
 interface PPB_Gamepad_Dev {
   /**
    * Samples the current state of the connected gamepads.
    */
-  void SampleGamepads(
+  void Sample(
       [in] PP_Instance instance,
-      [out] PP_GamepadsData_Dev data);
+      [out] PP_GamepadsSampleData_Dev data);
 
 };
diff --git a/ppapi/c/dev/ppb_gamepad_dev.h b/ppapi/c/dev/ppb_gamepad_dev.h
index e37362b..33a0f4c 100644
--- a/ppapi/c/dev/ppb_gamepad_dev.h
+++ b/ppapi/c/dev/ppb_gamepad_dev.h
@@ -3,17 +3,18 @@
  * found in the LICENSE file.
  */
 
-/* From dev/ppb_gamepad_dev.idl modified Tue Feb  7 12:49:02 2012. */
+/* From dev/ppb_gamepad_dev.idl modified Mon Feb 27 13:23:13 2012. */
 
 #ifndef PPAPI_C_DEV_PPB_GAMEPAD_DEV_H_
 #define PPAPI_C_DEV_PPB_GAMEPAD_DEV_H_
 
+#include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_macros.h"
 #include "ppapi/c/pp_stdint.h"
 
-#define PPB_GAMEPAD_DEV_INTERFACE_0_1 "PPB_Gamepad(Dev);0.1"
-#define PPB_GAMEPAD_DEV_INTERFACE PPB_GAMEPAD_DEV_INTERFACE_0_1
+#define PPB_GAMEPAD_DEV_INTERFACE_0_2 "PPB_Gamepad(Dev);0.2"
+#define PPB_GAMEPAD_DEV_INTERFACE PPB_GAMEPAD_DEV_INTERFACE_0_2
 
 /**
  * @file
@@ -22,8 +23,6 @@
  */
 
 
-#pragma pack(push, 1)
-
 /**
  * @addtogroup Structs
  * @{
@@ -31,27 +30,13 @@
 /**
  * The data for one gamepad device.
  */
-struct PP_GamepadData_Dev {
-  /**
-   * Is there a gamepad connected at this index? If this is false, no other
-   * data in this structure is valid.
-   */
-  char connected;
-  /**
-   * String identifier for the type of device/manufacturer.
-   */
-  uint16_t id[128];
-  /**
-   * Monotonically increasing value that is incremented when the data have
-   * been updated.
-   */
-  uint64_t timestamp;
+struct PP_GamepadSampleData_Dev {
   /**
    * Number of valid elements in the |axes| array.
    */
   uint32_t axes_length;
   /**
-   * Normalized values for the axes, indices valid up to |axesLength|-1. Axis
+   * Normalized values for the axes, indices valid up to |axes_length|-1. Axis
    * values range from -1..1, and are in order of "importance".
    */
   float axes[16];
@@ -60,31 +45,49 @@ struct PP_GamepadData_Dev {
    */
   uint32_t buttons_length;
   /**
-   * Normalized values for the buttons, indices valid up to |buttonsLength|
+   * Normalized values for the buttons, indices valid up to |buttons_length|
    * - 1. Button values range from 0..1, and are in order of importance.
    */
   float buttons[32];
+  /**
+   * Monotonically increasing value that is incremented when the data have
+   * been updated.
+   */
+  double timestamp;
+  /**
+   * Identifier for the type of device/manufacturer.
+   */
+  uint16_t id[128];
+  /**
+   * Is there a gamepad connected at this index? If this is false, no other
+   * data in this structure is valid.
+   */
+  PP_Bool connected;
+  /* Padding to make the struct the same size between 64 and 32. */
+  char unused_pad_[4];
 };
+PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_GamepadSampleData_Dev, 472);
 
 /**
  * The data for all gamepads connected to the system.
  */
-struct PP_GamepadsData_Dev {
+struct PP_GamepadsSampleData_Dev {
   /**
    * Number of valid elements in the |items| array.
    */
   uint32_t length;
+  /* Padding to make the struct the same size between 64 and 32. */
+  char unused_pad_[4];
   /**
    * Data for an individual gamepad device connected to the system.
    */
-  struct PP_GamepadData_Dev items[4];
+  struct PP_GamepadSampleData_Dev items[4];
 };
+PP_COMPILE_ASSERT_STRUCT_SIZE_IN_BYTES(PP_GamepadsSampleData_Dev, 1896);
 /**
  * @}
  */
 
-#pragma pack(pop)
-
 /**
  * @addtogroup Interfaces
  * @{
@@ -93,15 +96,14 @@ struct PP_GamepadsData_Dev {
  * The <code>PPB_Gamepad_Dev</code> interface allows retrieving data from
  * gamepad/joystick devices that are connected to the system.
  */
-struct PPB_Gamepad_Dev_0_1 {
+struct PPB_Gamepad_Dev_0_2 {
   /**
    * Samples the current state of the connected gamepads.
    */
-  void (*SampleGamepads)(PP_Instance instance,
-                         struct PP_GamepadsData_Dev* data);
+  void (*Sample)(PP_Instance instance, struct PP_GamepadsSampleData_Dev* data);
 };
 
-typedef struct PPB_Gamepad_Dev_0_1 PPB_Gamepad_Dev;
+typedef struct PPB_Gamepad_Dev_0_2 PPB_Gamepad_Dev;
 /**
  * @}
  */
diff --git a/ppapi/examples/gamepad/gamepad.cc b/ppapi/examples/gamepad/gamepad.cc
index 60ef589..7006dd1 100644
--- a/ppapi/examples/gamepad/gamepad.cc
+++ b/ppapi/examples/gamepad/gamepad.cc
@@ -49,9 +49,6 @@ class MyInstance : public pp::Instance {
         pp::Module::Get()->GetBrowserInterface(PPB_GAMEPAD_DEV_INTERFACE));
     if (!gamepad_)
       return false;
-
-    RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE |
-                       PP_INPUTEVENT_CLASS_KEYBOARD);
     return true;
   }
 
@@ -92,27 +89,29 @@ class MyInstance : public pp::Instance {
     if (image.is_null())
       return image;
 
-    PP_GamepadsData_Dev gamepad_data;
-    gamepad_->SampleGamepads(pp_instance(), &gamepad_data);
-
-    int width2 = size.width() / 2;
-    int height2 = size.height() / 2;
-    // Draw 2 axes
-    for (size_t i = 0; i < gamepad_data.items[0].axes_length; i += 2) {
-      int x = static_cast<int>(
-          gamepad_data.items[0].axes[i + 0] * width2 + width2);
-      int y = static_cast<int>(
-          gamepad_data.items[0].axes[i + 1] * height2 + height2);
-      uint32_t box_bgra = 0x80000000;  // Alpha 50%.
-      FillRect(&image, x - 3, y - 3, 7, 7, box_bgra);
-    }
-
-    for (size_t i = 0; i < gamepad_data.items[0].buttons_length; ++i) {
-      float button_val = gamepad_data.items[0].buttons[i];
-      uint32_t colour = static_cast<uint32_t>((button_val * 192) + 63) << 24;
-      int x = i * 8 + 10;
-      int y = 10;
-      FillRect(&image, x - 3, y - 3, 7, 7, colour);
+    PP_GamepadsSampleData_Dev gamepad_data;
+    gamepad_->Sample(pp_instance(), &gamepad_data);
+
+    if (gamepad_data.length > 1 && gamepad_data.items[0].connected) {
+      int width2 = size.width() / 2;
+      int height2 = size.height() / 2;
+      // Draw 2 axes
+      for (size_t i = 0; i < gamepad_data.items[0].axes_length; i += 2) {
+        int x = static_cast<int>(
+            gamepad_data.items[0].axes[i + 0] * width2 + width2);
+        int y = static_cast<int>(
+            gamepad_data.items[0].axes[i + 1] * height2 + height2);
+        uint32_t box_bgra = 0x80000000;  // Alpha 50%.
+        FillRect(&image, x - 3, y - 3, 7, 7, box_bgra);
+      }
+
+      for (size_t i = 0; i < gamepad_data.items[0].buttons_length; ++i) {
+        float button_val = gamepad_data.items[0].buttons[i];
+        uint32_t colour = static_cast<uint32_t>((button_val * 192) + 63) << 24;
+        int x = i * 8 + 10;
+        int y = 10;
+        FillRect(&image, x - 3, y - 3, 7, 7, colour);
+      }
     }
     return image;
   }
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/browser_ppb_gamepad_rpc_server.cc b/ppapi/native_client/src/shared/ppapi_proxy/browser_ppb_gamepad_rpc_server.cc
index 313e83d..7ef24ca 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/browser_ppb_gamepad_rpc_server.cc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/browser_ppb_gamepad_rpc_server.cc
@@ -21,12 +21,12 @@ void PpbGamepadRpcServer::PPB_Gamepad_SampleGamepads(
       nacl_abi_size_t* pads_bytes, char* pads) {
   NaClSrpcClosureRunner runner(done);
   rpc->result = NACL_SRPC_RESULT_APP_ERROR;
-  if (*pads_bytes != sizeof(struct PP_GamepadsData_Dev))
+  if (*pads_bytes != sizeof(struct PP_GamepadsSampleData_Dev))
     return;
 
-  PPBGamepadInterface()->SampleGamepads(
+  PPBGamepadInterface()->Sample(
       instance,
-      reinterpret_cast<struct PP_GamepadsData_Dev*>(pads));
+      reinterpret_cast<struct PP_GamepadsSampleData_Dev*>(pads));
   DebugPrintf("PPB_Gamepad::SampleGamepads\n");
 
   rpc->result = NACL_SRPC_RESULT_OK;
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_gamepad.cc b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_gamepad.cc
index 021e6f2..2e2256b 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_gamepad.cc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_gamepad.cc
@@ -14,14 +14,15 @@ namespace ppapi_proxy {
 
 namespace {
 
-void SampleGamepads(PP_Instance instance, struct PP_GamepadsData_Dev* pads) {
+void SampleGamepads(PP_Instance instance,
+                    struct PP_GamepadsSampleData_Dev* pads) {
   DebugPrintf("PPB_Gamepad::SampleGamepads: instance=%"NACL_PRId32"\n",
               instance);
   if (pads == NULL)
     return;
 
   nacl_abi_size_t pads_bytes =
-      static_cast<nacl_abi_size_t>(sizeof(struct PP_GamepadsData_Dev));
+      static_cast<nacl_abi_size_t>(sizeof(struct PP_GamepadsSampleData_Dev));
   NaClSrpcError srpc_result =
       PpbGamepadRpcClient::PPB_Gamepad_SampleGamepads(
           GetMainSrpcChannel(),
diff --git a/ppapi/proxy/ppb_instance_proxy.cc b/ppapi/proxy/ppb_instance_proxy.cc
index 1f71e87..8842783 100644
--- a/ppapi/proxy/ppb_instance_proxy.cc
+++ b/ppapi/proxy/ppb_instance_proxy.cc
@@ -288,7 +288,7 @@ PP_Bool PPB_Instance_Proxy::FlashGetScreenSize(PP_Instance instance,
 }
 
 void PPB_Instance_Proxy::SampleGamepads(PP_Instance instance,
-                                        PP_GamepadsData_Dev* data) {
+                                        PP_GamepadsSampleData_Dev* data) {
   NOTIMPLEMENTED();
 }
 
diff --git a/ppapi/proxy/ppb_instance_proxy.h b/ppapi/proxy/ppb_instance_proxy.h
index 80927a3..60661f7 100644
--- a/ppapi/proxy/ppb_instance_proxy.h
+++ b/ppapi/proxy/ppb_instance_proxy.h
@@ -72,8 +72,8 @@ class PPB_Instance_Proxy : public InterfaceProxy,
                                     PP_Bool fullscreen) OVERRIDE;
   virtual PP_Bool FlashGetScreenSize(PP_Instance instance, PP_Size* size)
       OVERRIDE;
-  virtual void SampleGamepads(PP_Instance instance, PP_GamepadsData_Dev* data)
-      OVERRIDE;
+  virtual void SampleGamepads(PP_Instance instance,
+                              PP_GamepadsSampleData_Dev* data) OVERRIDE;
   virtual int32_t RequestInputEvents(PP_Instance instance,
                                      uint32_t event_classes) OVERRIDE;
   virtual int32_t RequestFilteringInputEvents(PP_Instance instance,
diff --git a/ppapi/thunk/interfaces_ppb_public_dev.h b/ppapi/thunk/interfaces_ppb_public_dev.h
index 94696e4..5a7ca47 100644
--- a/ppapi/thunk/interfaces_ppb_public_dev.h
+++ b/ppapi/thunk/interfaces_ppb_public_dev.h
@@ -41,7 +41,7 @@ PROXIED_IFACE(PPB_FileChooser, PPB_FILECHOOSER_DEV_INTERFACE_0_5,
               PPB_FileChooser_Dev_0_5)
 PROXIED_IFACE(PPB_Instance, PPB_CHAR_SET_DEV_INTERFACE_0_4, PPB_CharSet_Dev_0_4)
 PROXIED_IFACE(PPB_Instance, PPB_CONSOLE_DEV_INTERFACE_0_1, PPB_Console_Dev_0_1)
-PROXIED_IFACE(PPB_Instance, PPB_GAMEPAD_DEV_INTERFACE_0_1, PPB_Gamepad_Dev_0_1)
+PROXIED_IFACE(PPB_Instance, PPB_GAMEPAD_DEV_INTERFACE_0_2, PPB_Gamepad_Dev_0_2)
 PROXIED_IFACE(PPB_Instance, PPB_URLUTIL_DEV_INTERFACE_0_6, PPB_URLUtil_Dev_0_6)
 UNPROXIED_IFACE(PPB_Instance, PPB_ZOOM_DEV_INTERFACE_0_2, PPB_Zoom_Dev_0_2)
 PROXIED_IFACE(NoAPIName, PPB_KEYBOARD_INPUT_EVENT_DEV_INTERFACE_0_1,
diff --git a/ppapi/thunk/ppb_gamepad_thunk.cc b/ppapi/thunk/ppb_gamepad_thunk.cc
index 9bf2122..376faa4 100644
--- a/ppapi/thunk/ppb_gamepad_thunk.cc
+++ b/ppapi/thunk/ppb_gamepad_thunk.cc
@@ -13,7 +13,7 @@ namespace thunk {
 
 namespace {
 
-void SampleGamepads(PP_Instance instance, PP_GamepadsData_Dev* data) {
+void SampleGamepads(PP_Instance instance, PP_GamepadsSampleData_Dev* data) {
   EnterFunction<PPB_Instance_FunctionAPI> enter(instance, true);
   if (enter.failed())
     return;
@@ -26,7 +26,7 @@ const PPB_Gamepad_Dev g_ppb_gamepad_thunk = {
 
 }  // namespace
 
-const PPB_Gamepad_Dev* GetPPB_Gamepad_Dev_0_1_Thunk() {
+const PPB_Gamepad_Dev* GetPPB_Gamepad_Dev_0_2_Thunk() {
   return &g_ppb_gamepad_thunk;
 }
 
diff --git a/ppapi/thunk/ppb_instance_api.h b/ppapi/thunk/ppb_instance_api.h
index 3055d73..87ea79c 100644
--- a/ppapi/thunk/ppb_instance_api.h
+++ b/ppapi/thunk/ppb_instance_api.h
@@ -83,7 +83,7 @@ class PPB_Instance_FunctionAPI {
 
   // Gamepad.
   virtual void SampleGamepads(PP_Instance instance,
-                              PP_GamepadsData_Dev* data) = 0;
+                              PP_GamepadsSampleData_Dev* data) = 0;
 
   // InputEvent.
   virtual int32_t RequestInputEvents(PP_Instance instance,