NPAPI:Pepper

Status

Under consideration.

Background

Over the past few months a number of us have also been discussing some of the issues facing NPAPI as a platform independent browser plugin framework. First, we feel there are some changes needed to NPAPI to keep up with recent developments in browser technology, such as out of process plugin execution. Second, while NPAPI provides an extensive framework for writing plugins, many end up relying on operating system or browser platform specific features. This is especially true of windowed plugins that implement 2D or 3D graphics, where almost the entirety of the plugin may consist of operating system specific graphics or event APIs. Third, both windowed and windowless plugins are difficult to composite with other layers correctly today, making it difficult for a page author to achieve the same look and feel across browsers and operating systems. This proposal intends to be a starting point for addressing these issues, and consists of four topics.

1. Giving a clear semantics to NPAPI across browsers that implement plugins in a separate process from the renderer/browser itself.
2. Integrating plugin rendering with the browser's compositing process, allowing HTML overlays, etc., to work correctly with plugins.
3. Defining events, 2D rasterization, and an initial take on 3D graphics access in a way that is common across operating systems and browsers.
4. Determining which plugins are available to a browser without loading the plugin. Although a much smaller issue, it is currently one of the more platform specific portions of NPAPI and one that lends itself to a relatively simple solution.

A somewhat related issue is how to extend NPAPI to provide platform independent access to new hardware or software features such as digital cameras, SD cards, bar code readers, accelerometers, webcams, microphones, etc. While certainly important, this is deferred to future discussions.

The "Pepper" Platform

To provide these improvements to NPAPI we propose that the changes below be another platform, called "Pepper", that may be implemented by a browser and requested by a plugin at startup.

A plugin may call NPN_GetValue() with the following NPNVariable to query the browser whether it supports the Pepper platform:

/* TRUE if the browser supports the Pepper platform */
NPNVsupportsPepperBool = xxxx

Once the plugin finds Pepper to be supported, it calls NPN_SetValue() to tell the browser to use that platform. We're adding a new NPNVariable for this:

NPNVpluginUsePepperPlatform = yyyy /* TRUE if we should use the Pepper platform */

Out of process plugins

The current NPAPI model defines the threading model within one process such that whatever thread invokes NPP_New is the only thread that may invoke NPN_* functions. Several browsers either currently support or are considering moving NPAPI plugins to a separate process from the renderer process (responsible for rendering a page 's content). With these processes distinct, we have the following:

R = renderer process
Tr = thread in R that causes NPP_New to be invoked
P = plugin process
Tp = thread in P that invokes NPP_New in response to the renderer

Thread model for NPN_* calls

We propose that NPN_* calls, with only one exception, can only be made from Tp. This allows us to maintain an important invariant, namely that if Tp is executing any NPP code, then Tr is blocked. This eliminates the possibility of simultaneous JavaScript and plugin activities.

NPN_PluginThreadAsyncCall

The one exception to NPN_* calls is NPN_PluginThreadAsyncCall.

void    NP_LOADDS NPN_PluginThreadAsyncCall(NPP instance,
                                            void (*func) (void *),
                                            void *userData);

The semantics of NPN_PluginThreadAsyncCall remain fundamentally the same, just with respect to P:

• It can be called from any thread in P.
• Invoking it eventually causes an NPP callback on Tp to func, passing userData.

We make a couple of other implementation comments that make this more usable and help avoid possible deadlocks:

• If two callbacks are requested by the same thread, they should be invoked in the same order they were requested.
• The implementation of NPN_PluginThreadAsyncCall may not call func directly, even if called on Tp, because we need to guarantee the state of Tr and this risks deadlock.

We observe that implementing NPN_PluginThreadAsyncCall this way results in additional call/callback/call latency for NPN_* calls. We believe this is reasonable to provide a well-defined interaction, but realize we may need to address the efficiency of this mechanism.

Plugins and rendering

Currently plugins typically display 2D graphics in one of two modes: windowless or windowed. In the current state of affairs windowless plugins are typically given an RGB surface containing the contents of lower layers and they composite themselves. This constrains the use of transparency and complicates plugins that are not the top or bottom layer. Furthermore, basically all access to 3D accelerated graphics are through the latter. Windowed plugins provide a number of challenges to plugin and browser writers. First, windowed plugins are essentially given a handle to an operating system native window, from which all interaction by the plugin is completely platform-specific. Second, native windows make it very difficult for the browser to do CSS overlays, etc. Third, although NPAPI provides the NPP_HandleEvent API, this is not well-defined with respect to native windowing system events.

To these ends we propose, for both 2D and 3D:

• Only windowless plugins should be supported.
• Compositing should be done by outside the plugin itself, which should only produce an RGBA (2D) or a texture (3D).
• No native windowing system events should be delivered to plugins.

This proposal is clearer at this moment regarding 2D graphics. We expect we may need to pass some state (2d vs. 3d, hardware vs. raster, etc.) in through other calls and/or with some extensions to the data structures we propose below.

An Example

A video game looks abstractly like

  ...
  while (true) {
    HandleEvents()
    Simulate(gettimeofday())
    Draw()
  }
  ...

We propose that we continue to set graphics attributes through the existing NPN_GetValue/NPN_SetValue interfaces with some new variables TBD.

There are four APIs that would be involved in supporting this from the browser.

NPP_SetWindow and Windowless Plugins

Whereas currently NPP_SetWindow passes both some geometry information and a handle to a native window (for windowed plugins), in our proposal, it only conveys geometry and format information. For example.

typedef struct _NPWindow {
  void*    window;   // UNUSED
  uint32_t x;        // Position of plugin top left corner relative to top left
  uint32_t y;        // of renderer page. Y increases going down.
  uint32_t width;    // maximum window size
  uint32_t height;
  NPRect   clipRect; // UNUSED
  void*    ws_info;  // Pixel format of the raster backing store. A NPRasterWindowInfo struct.
  NPWindowType type; // UNUSED
} NPWindow;

enum NPPixelFormat {
  NP_RGBA_8888,
  NP_RGB_565,
  // TBD: other pixel formats
};

typedef struct _NPRasterWindowInfo {
  NPPixelFormat format;
} NPRasterWindowInfo;

NPError NP_LOADDS NPP_SetWindow(NPP instance,
                                NPWindow* window);

Getting a Device Context to Draw Into

  PARAMS (details remain to be worked out, but at least):
    - rectangle plugin will draw into
    - discard bit (don't bother to initialize the memory in that rectangle)
  2D DC:
    - x, y, width, height
    - visible rectangles[] // serve as hints
    - stride (byte/pixel difference between (x,y) and (x,y+1))
    - x, y for byte zero of the buffer
    - void* buffer // size is as requested by PARAMS regardless of visible rectangles.

  void NPN_GetDeviceContext(NPP instance, PARAMS, NPDeviceContext** context)

• Allows the plugin to request that the renderer create a context to draw into and call the plugin back.
• On return, the renderer informs the plugin where it can draw into (in *context).

Publishing the Context to the Renderer

  void NPN_PublishDeviceContext(NPP instance, NPDeviceContext* context)

• The plugin informs the renderer that it has drawn into context and that the renderer may composite from it.
• After this call the plugin may no longer draw into the context (it may be deallocated, etc.)

Notification a Context was Displayed

Video players, video games, and other timing sensitive plugins typically adjust their simulation to adapt to the speed at which frames are placed on the screen. A call from the renderer indicating when the bits from a context have reached the screen is needed.

  void NPP_DeviceContextDisplayed(NPP instance)

• The renderer informs the plugin that the last published device context was displayed on the screen.
• For performance we will most likely want to be able to call NPN_GetDeviceContext before the NPP_DeviceContextDisplayed call from the previous NPN_PublishDeviceContext has arrived.
• This API could also perhaps be done through an NPEvent of the appropriate type.

Optimizations and Legacy APIs

There are two possible performance opportunities that should be noted. First, given the threading model we have defined, it may be desirable to allow NPN_GetDeviceContext and NPN_PublishDeviceContext to be called from other plugin threads than Tp. This would eliminate the need to do the associated NPN_PluginThreadAsyncCall, and avoid the context switch penalties that might be associated.

Second, in order to avoid drawing an entire region on the screen when only a small portion is updated, it may be useful for the plugin to use existing APIs to mark only a small region as needing to be updated by the next NPN_PublishDeviceContext.

  void NPN_InvalidateRect(NPP instance, NPRect* invalidRect)

• The plugin informs the renderer that it would like to replace the contents of the specified rectangle.

Event Handling

Plugins should receive all their events from NPP_HandleEvent. We believe that standardizing the event types and payloads based on, for example, DOM events, would be sufficient to provide browser and OS independent events. If not, the goal can be accomplished by possibly extending the set of event types or data on the event structures to convey more information.

Events

Background

All events to an untrusted Pepper module will arrive via NPHandleEvent?(). For the most part, think of this as NPHandleEvent?() as it appears in traditional NPAPI, but instead of recieving a void* package of blind data that must be type cast to an operating system specific event structure, Pepper's version of NPHandleEvent?() will recieve pointers to Pepper's platform independent NPEvent structure.

int16_t NPP_HandleEvent(NPP_Instance instance, const NPEvent *event) This platform independent event structure will be principally based on WebKit's internal events. Some light translation may need to occur for platform neutrality, and platform specific fields in the WebKit events will be dropped. Also, Pepper is a 'C' style API, so instead of using classes, Pepper's events will be defined as C structures. They will also use specifically sized types (int32_t, int16_t, int8_t, etc.) to avoid sizeof(int) and sizeof(wchar) differences between compilers and machine architectures, and have very strict padding and alignment specifications.

This specification is version 1.0 of events in Pepper. If future events are added, or additional fields are added to existing events, we'll need a way for the Native Client application to query (or negotiate) what version of events are supported by the browser. If significant changes are made to WebKit's event model, we may need to add additional trusted code to maintain backwards compatibility with existing Native Client applications. This applies not only to new fields or changes to the ranges of existing fields, but is also especially important for changes or differences in behaviours across multiple operating systems (for example, are mouse movements reported outside the embedded area while a button is held down and the initial mouse down event occurred within the embedded area) Subsequent versions of Pepper events may need to support gesture & touch based events, such as finger pinching and stretching to support zoom in / zoom out for maps & photo editors.

The Native Client application can use NPN_GetValue() & NPN_SetValue() to query and set future event models. Currently, only version 1.0 model is supported, and it should be safe to assume that version 1.0 model will always be available, and will be the default at startup.

Additional Items

There is no timer event, see NPN_ScheduleTimer() and NPN_UnscheduleTimer() for timer support. There is no quit event during application shutdown, see JavaScript's "onunload" There is no resize event; see NPN_SetWindow(), which will be correctly serialized with respect to event order.

Currently, we are proposing a platform neutral event for focus gained/lost, and a similar event for minimize/background tab. There is also a proposal for NPAPI to support three new NPN functions: NPN_UnfocusInstance(), NPN_LostFocus(), and NPN_GotFocus(). The NPAPI proposal uses NPN functions in leu of events for a few reasons, two of which are: 1) they didn't want to define what the focus event should be for each OS platform, 2) allow the application to explicitly give up focus. Since PEPPER events are platform neutral, the 1st reason doesn't really apply here. The 2nd reason might be good enough to consider using AKH instead of focus events. The downside is that as more events become NPN_* functions, the event model starts to become an inconsistent mix of traditional events and NPN_* functions. https://wiki.mozilla.org/Plugins:AdvancedKeyHandling

Pepper NPAPI Event Structures

It is important that all compilers, on all supported platforms, both trusted and untrusted, preserve structure order, field size, and alignment padding, as these structures might be used as a bit copyable wire format between different processes. These seperate processses could be compiled using different compilers and/or compilier options, while sharing these structures via shared memory. For the definitions below, the byte offset for each field is in square brackets. Unused portions of the event structure should be treated as undefined data.

enum NPMouseButtons {
  // Each value explicitly set, and must match between trusted & untrusted code.
  NPMouseButton_None    = -1,
  NPMouseButton_Left    = 0,
  NPMouseButton_Middle  = 1,
  NPMouseButton_Right   = 2,
  // End of Native Client event specification version 1.0
  // Additional future mouse button enums go here...
};

enum NPEventTypes {
  // Each value explicitly set, and must match between trusted & untrusted code.
  NPEventType_Undefined   = -1,

  // events                         relevant union to use in NPEvent
  NPEventType_MouseDown   = 0,   // NPMouseEvent struct
  NPEventType_MouseUp     = 1,   // NPMouseEvent struct
  NPEventType_MouseMove   = 2,   // NPMouseEvent struct
  NPEventType_MouseEnter  = 3,   // NPMouseEvent struct
  NPEventType_MouseLeave  = 4,   // NPMouseEvent struct
  NPEventType_MouseWheel  = 5,   // NPMouseWheelEvent struct
  NPEventType_RawKeyDown  = 6,   // NPKeyEvent struct
  NPEventType_KeyDown     = 7,   // NPKeyEvent struct
  NPEventType_KeyUp       = 8,   // NPKeyEvent struct
  NPEventType_Char        = 9,   // NPCharEvent struct
  NPEventType_Minimize    = 10,  // NPMinimizeEvent struct
  NPEventType_Focus       = 11,  // NPFocusEvent struct
  NPEventType_Device      = 12,  // NPDeviceEvent struct
  // End of Native Client specific event specification version 1.0
  // Additional future Native Client events go here...
};

enum NPEventModifiers {
  // Each value explicitly set, and must match between trusted & untrusted code.
  NPEventModifier_ShiftKey         = 1 << 0;    // Does not differentiate between left/right keys
  NPEventModifier_ControlKey       = 1 << 1;    // Does not differentiate between left/right keys
  NPEventModifier_AltKey           = 1 << 2;    // Does not differentiate between left/right keys
  NPEventModifier_MetaKey          = 1 << 3;    // Does not differentiate between left/right keys
  NPEventModifier_IsKeyPad         = 1 << 4;
  NPEventModifier_IsAutoRepeat     = 1 << 5;
  NPEventModifier_LeftButtonDown   = 1 << 6;
  NPEventModifier_MiddleButtonDown = 1 << 7;
  NPEventModifier_RightButtonDown  = 1 << 8;
  // End of Native Client event specification version 1.0
  // Additional future event modifiers go here...
};

struct NPKeyEvent {
  // Structure layout must match between trusted & untrusted code.
  uint32_t modifier;             // [0] : NPModifier
  uint32_t normalizedKeyCode;    // [4] : key codes from Chromium's keyboard_codes_posix.h
};

struct NPCharacterEvent {
  uint32_t modifier;             // [0] : NPModifier
  uint16_t text[4];              // [4] : 32bit wchar
  uint16_t unmodifiedText[4];    // [8] : 32bit wchar
  // End of Native Client event specification version 1.0
  // Additional future key event fields go here...
};

struct NPMouseEvent {
  // Structure layout must match between trusted & untrusted code.
  uint32_t modifier;             // [0] : NPModifier
  int32_t button;                // [4] : NPMouseButtons
  int32_t x;                     // [8] : Relative to upper left corner of embedded area, in units of pixels
  int32_t y;                     // [12]: Relative to upper left corner of embedded area (+y down)
  int32_t clickCount;            // [16]: Number of button clicks
  // End of Native Client event specification version 1.0
  // Additional future mouse event fields go here...
};

struct NPMouseWheelEvent {
  // Structure layout must match between trusted & untrusted code.
  uint32_t modifier;             // [0] : NPModifier
  float deltaX;                  // [4] : Positive deltaX indicate scroll left, in scroll wheel units. 
  float deltaY;                  // [8] : Positive deltaY indicate scroll up, in scroll wheel units.
                                 //         On Windows, one scroll wheel click is a delta of 100.0
  float wheelTicksX;             // [12]: Positive wheelTicksX indicate scroll left.
  float wheelTicksY;             // [16]: Positive wheelTicksY indicate scroll up.
                                 //         Wheel ticks can be fractional values on certain devices.
  uint32_t scrollByPage;         // [20]: 0 - scroll by line, 1 - scroll by page
  // End of Native Client event specification version 1.0
  // Additional future mouse wheel event fields go here...
};

struct NPDeviceEvent {
  // Structure layout must match between trusted & untrusted code.
  // This is a generic event type that devices (discovered via NPN_SetWindow) may use
  // to deliver events to NPN_HandleEvent().
  // Note: this area is under construction

  uint32_t device_uid;           // [0] : unique id of device (comes in on PEPPER NPN_SetWindow)
  uint32_t subtype;              // [4] : device event subtype
  uint8_t generic[0];            // [8] : payload is typecast based on device uid & subtype
};

struct NPMinimizeEvent {
  // Structure layout must match between trusted & untrusted code.
  // Minimizing may also include becoming a background/foreground tab.
  int32_t value;                 // [0] : New value
                                 //         0 = transitioning out of minimized state
                                 //         1 = transitioning to a minimized state
  // End of Native Client event specification version 1.0
  // Additional future minimize event fields go here...
};

struct NPFocusEvent {
  // Structure layout must match between trusted & untrusted code.
  // The embedded Native Client area is gaining or losing keyboard focus.
  int32_t value;                 // [0] : New value
                                 //         0 = losing focus
                                 //         1 = gaining focus
  // End of Native Client event specification version 1.0
  // Additional future focus event fields go here...
};

struct NPEvent {
  // Structure layout must match between trusted & untrusted code.
  int32_t type;                  // [0] : NPEventTypes
  uint32_t size;                 // [4] : Size in bytes of _this_ event structure.
  double timeStampSeconds;       // [8] : Time of creation; seconds since epoch.

  union {
    // [16]: Info specific to each event type
    NPKeyEvent key;
    NPCharacterEvent character;
    NPMouseEvent mouse;
    NPMouseWheelEvent wheel;
    NPMinimizeEvent minimize;
    NPFocusEvent focus;
    NPDeviceEvent device;
    // End of Native Client event specification version 1.0
    // Additional future event type structures go here...
  };
};

Keycodes used by NPKeyEvent.normalizedKeyCode (keyboard_codes_posix.h)

enum {
  VKEY_BACK = 0x08,
  VKEY_TAB = 0x09,
  VKEY_CLEAR = 0x0C,
  VKEY_RETURN = 0x0D,
  VKEY_SHIFT = 0x10,
  VKEY_CONTROL = 0x11,
  VKEY_MENU = 0x12,
  VKEY_PAUSE = 0x13,
  VKEY_CAPITAL = 0x14,
  VKEY_KANA = 0x15,
  VKEY_HANGUL = 0x15,
  VKEY_JUNJA = 0x17,
  VKEY_FINAL = 0x18,
  VKEY_HANJA = 0x19,
  VKEY_KANJI = 0x19,
  VKEY_ESCAPE = 0x1B,
  VKEY_CONVERT = 0x1C,
  VKEY_NONCONVERT = 0x1D,
  VKEY_ACCEPT = 0x1E,
  VKEY_MODECHANGE = 0x1F,
  VKEY_SPACE = 0x20,
  VKEY_PRIOR = 0x21,
  VKEY_NEXT = 0x22,
  VKEY_END = 0x23,
  VKEY_HOME = 0x24,
  VKEY_LEFT = 0x25,
  VKEY_UP = 0x26,
  VKEY_RIGHT = 0x27,
  VKEY_DOWN = 0x28,
  VKEY_SELECT = 0x29,
  VKEY_PRINT = 0x2A,
  VKEY_EXECUTE = 0x2B,
  VKEY_SNAPSHOT = 0x2C,
  VKEY_INSERT = 0x2D,
  VKEY_DELETE = 0x2E,
  VKEY_HELP = 0x2F,
  VKEY_0 = 0x30,
  VKEY_1 = 0x31,
  VKEY_2 = 0x32,
  VKEY_3 = 0x33,
  VKEY_4 = 0x34,
  VKEY_5 = 0x35,
  VKEY_6 = 0x36,
  VKEY_7 = 0x37,
  VKEY_8 = 0x38,
  VKEY_9 = 0x39,
  VKEY_A = 0x41,
  VKEY_B = 0x42,
  VKEY_C = 0x43,
  VKEY_D = 0x44,
  VKEY_E = 0x45,
  VKEY_F = 0x46,
  VKEY_G = 0x47,
  VKEY_H = 0x48,
  VKEY_I = 0x49,
  VKEY_J = 0x4A,
  VKEY_K = 0x4B,
  VKEY_L = 0x4C,
  VKEY_M = 0x4D,
  VKEY_N = 0x4E,
  VKEY_O = 0x4F,
  VKEY_P = 0x50,
  VKEY_Q = 0x51,
  VKEY_R = 0x52,
  VKEY_S = 0x53,
  VKEY_T = 0x54,
  VKEY_U = 0x55,
  VKEY_V = 0x56,
  VKEY_W = 0x57,
  VKEY_X = 0x58,
  VKEY_Y = 0x59,
  VKEY_Z = 0x5A,
  VKEY_LWIN = 0x5B,
  VKEY_RWIN = 0x5C,
  VKEY_APPS = 0x5D,
  VKEY_SLEEP = 0x5F,
  VKEY_NUMPAD0 = 0x60,
  VKEY_NUMPAD1 = 0x61,
  VKEY_NUMPAD2 = 0x62,
  VKEY_NUMPAD3 = 0x63,
  VKEY_NUMPAD4 = 0x64,
  VKEY_NUMPAD5 = 0x65,
  VKEY_NUMPAD6 = 0x66,
  VKEY_NUMPAD7 = 0x67,
  VKEY_NUMPAD8 = 0x68,
  VKEY_NUMPAD9 = 0x69,
  VKEY_MULTIPLY = 0x6A,
  VKEY_ADD = 0x6B,
  VKEY_SEPARATOR = 0x6C,
  VKEY_SUBTRACT = 0x6D,
  VKEY_DECIMAL = 0x6E,
  VKEY_DIVIDE = 0x6F,
  VKEY_F1 = 0x70,
  VKEY_F2 = 0x71,
  VKEY_F3 = 0x72,
  VKEY_F4 = 0x73,
  VKEY_F5 = 0x74,
  VKEY_F6 = 0x75,
  VKEY_F7 = 0x76,
  VKEY_F8 = 0x77,
  VKEY_F9 = 0x78,
  VKEY_F10 = 0x79,
  VKEY_F11 = 0x7A,
  VKEY_F12 = 0x7B,
  VKEY_F13 = 0x7C,
  VKEY_F14 = 0x7D,
  VKEY_F15 = 0x7E,
  VKEY_F16 = 0x7F,
  VKEY_F17 = 0x80,
  VKEY_F18 = 0x81,
  VKEY_F19 = 0x82,
  VKEY_F20 = 0x83,
  VKEY_F21 = 0x84,
  VKEY_F22 = 0x85,
  VKEY_F23 = 0x86,
  VKEY_F24 = 0x87,
  VKEY_NUMLOCK = 0x90,
  VKEY_SCROLL = 0x91,
  VKEY_LSHIFT = 0xA0,
  VKEY_RSHIFT = 0xA1,
  VKEY_LCONTROL = 0xA2,
  VKEY_RCONTROL = 0xA3,
  VKEY_LMENU = 0xA4,
  VKEY_RMENU = 0xA5,
  VKEY_BROWSER_BACK = 0xA6,
  VKEY_BROWSER_FORWARD = 0xA7,
  VKEY_BROWSER_REFRESH = 0xA8,
  VKEY_BROWSER_STOP = 0xA9,
  VKEY_BROWSER_SEARCH = 0xAA,
  VKEY_BROWSER_FAVORITES = 0xAB,
  VKEY_BROWSER_HOME = 0xAC,
  VKEY_VOLUME_MUTE = 0xAD,
  VKEY_VOLUME_DOWN = 0xAE,
  VKEY_VOLUME_UP = 0xAF,
  VKEY_MEDIA_NEXT_TRACK = 0xB0,
  VKEY_MEDIA_PREV_TRACK = 0xB1,
  VKEY_MEDIA_STOP = 0xB2,
  VKEY_MEDIA_PLAY_PAUSE = 0xB3,
  VKEY_MEDIA_LAUNCH_MAIL = 0xB4,
  VKEY_MEDIA_LAUNCH_MEDIA_SELECT = 0xB5,
  VKEY_MEDIA_LAUNCH_APP1 = 0xB6,
  VKEY_MEDIA_LAUNCH_APP2 = 0xB7,
  VKEY_OEM_1 = 0xBA,
  VKEY_OEM_PLUS = 0xBB,
  VKEY_OEM_COMMA = 0xBC,
  VKEY_OEM_MINUS = 0xBD,
  VKEY_OEM_PERIOD = 0xBE,
  VKEY_OEM_2 = 0xBF,
  VKEY_OEM_3 = 0xC0,
  VKEY_OEM_4 = 0xDB,
  VKEY_OEM_5 = 0xDC,
  VKEY_OEM_6 = 0xDD,
  VKEY_OEM_7 = 0xDE,
  VKEY_OEM_8 = 0xDF,
  VKEY_OEM_102 = 0xE2,
  VKEY_PROCESSKEY = 0xE5,
  VKEY_PACKET = 0xE7,
  VKEY_ATTN = 0xF6,
  VKEY_CRSEL = 0xF7,
  VKEY_EXSEL = 0xF8,
  VKEY_EREOF = 0xF9,
  VKEY_PLAY = 0xFA,
  VKEY_ZOOM = 0xFB,
  VKEY_NONAME = 0xFC,
  VKEY_PA1 = 0xFD,
  VKEY_OEM_CLEAR = 0xFE,
  VKEY_UNKNOWN = 0
};

Plugin Registration

The current process of determining which plugins are available to the browser typically involves loading various shared libraries and querying them for types and extensions addressed by the plugin. We propose that more efficient method would be to add a special section to the shared library for the plugin.

The section, tentatively named .npapidesc, contains a sequence of strings of the form:

mimetype:[extension][,extension]*:description;

This enables browsers to scan the plugins without loading them, which becomes more difficult with out-of-process plugins and sandbox protection.