PPP_Instance interface contains pointers to a series of functions that you must implement in your module.
These functions can be trivial (simply return the default return value) unless you want your module to handle events such as change of focus or input events (keyboard/mouse) events.
Data Fields List
|PP_Bool(*||DidCreate )(PP_Instance instance, uint32_t argc, const char *argn, const char *argv)|
|void(*||DidDestroy )(PP_Instance instance)|
|void(*||DidChangeView )(PP_Instance instance, const struct PP_Rect *position, const struct PP_Rect *clip)|
|void(*||DidChangeFocus )(PP_Instance instance, PP_Bool has_focus)|
|PP_Bool(*||HandleDocumentLoad )(PP_Instance instance, PP_Resource url_loader)|
Data Fields Details
DidChangeFocus() is called when an instance has gained or lost focus.
Having focus means that keyboard events will be sent to the instance. An instance's default condition is that it will not have focus.
Note:Clicks on instances will give focus only if you handle the click event. Return
PPP_InputEvent (or use unfiltered events) to signal that the click event was handled. Otherwise, the browser will bubble the event and give focus to the element on the page that actually did end up consuming it. If you're not getting focus, check to make sure you're returning true from the mouse click in
[in] instance A
PP_Instanceidentifying the instance receiving the input event.
[in] has_focus Indicates the new focused state of the instance.
|void(* PPP_Instance::DidChangeView)(PP_Instance instance, const struct PP_Rect *position, const struct PP_Rect *clip)|
DidChangeView() is called when the position, the size, of the clip rectangle of the element in the browser that corresponds to this instance has changed.
A typical implementation will check the size of the
position argument and reallocate the graphics context when a different size is received. Note that this function will be called for scroll events where the size doesn't change, so you should always check that the size is actually different before doing any reallocations.
[in] instance A
PP_Instanceidentifying the instance that has changed.
[in] position The location on the page of the instance. This is relative to the top left corner of the viewport, which changes as the page is scrolled. Generally the size of this value will be used to create a graphics device, and the position is ignored (most things are relative to the instance so the absolute position isn't useful in most cases). [in] clip The visible region of the instance. This is relative to the top left of the module's coordinate system (not the page). If the module is invisible,
clipwill be (0, 0, 0, 0).
It's recommended to check for invisible instances and to stop generating graphics updates in this case to save system resources. It's not usually worthwhile, however, to generate partial updates according to the clip when the instance is partially visible. Instead, update the entire region. The time saved doing partial paints is usually not significant and it can create artifacts when scrolling (this notification is sent asynchronously from scrolling so there can be flashes of old content in the exposed regions).
|PP_Bool(* PPP_Instance::DidCreate)(PP_Instance instance, uint32_t argc, const char *argn, const char *argv)|
DidCreate() is a creation handler that is called when a new instance is created.
This function is called for each instantiation on the page, corresponding to one <embed> tag on the page.
Generally you would handle this call by initializing the information your module associates with an instance and creating a mapping from the given
PP_Instance handle to this data. The
PP_Instance handle will be used in subsequent calls to identify which instance the call pertains to.
It's possible for more than one instance to be created in a single module. This means that you may get more than one
OnCreate without an
OnDestroy in between, and should be prepared to maintain multiple states associated with each instance.
If this function reports a failure (by returning
PP_FALSE), the instance will be deleted.
[in] instance A new
PP_Instanceidentifying one instance of a module. This is an opaque handle.
[in] argc The number of arguments contained in
[in] argn An array of argument names. These argument names are supplied in the <embed> tag, for example:
<embed id="nacl_module" dimensions="2">will produce two argument names: "id" and "dimensions."
[in] argv An array of argument values. These are the values of the arguments listed in the <embed> tag, for example
<embed id="nacl_module" dimensions="2">will produce two argument values: "nacl_module" and "2". The indices of these values match the indices of the corresponding names in
PP_TRUEon success or
DidDestroy() is an instance destruction handler.
This function is called in many cases (see below) when a module instance is destroyed. It will be called even if DidCreate() returned failure.
Generally you will handle this call by deallocating the tracking information and the
PP_Instance mapping you created in the DidCreate() call. You can also free resources associated with this instance but this isn't required; all resources associated with the deleted instance will be automatically freed when this function returns.
The instance identifier will still be valid during this call, so the module can perform cleanup-related tasks. Once this function returns, the
PP_Instance handle will be invalid. This means that you can't do any asynchronous operations like network requests, file writes or messaging from this function since they will be immediately canceled.
Note: This function will always be skipped on untrusted (Native Client) implementations. This function may be skipped on trusted implementations in certain circumstances when Chrome does "fast shutdown" of a web page. Fast shutdown will happen in some cases when all module instances are being deleted, and no cleanup functions will be called. The module will just be unloaded and the process terminated.
[in] instance A
PP_Instanceidentifying one instance of a module.
HandleDocumentLoad() is called after initialize for a full-frame module that was instantiated based on the MIME type of a DOMWindow navigation.
This situation only applies to modules that are pre-registered to handle certain MIME types. If you haven't specifically registered to handle a MIME type or aren't positive this applies to you, your implementation of this function can just return
url_loader corresponds to a
PPB_URLLoader instance that is already opened. Its response headers may be queried using
PPB_URLLoader::GetResponseInfo. The reference count for the URL loader is not incremented automatically on behalf of the module. You need to increment the reference count yourself if you are going to keep a reference to it.
This method returns
PP_FALSE if the module cannot handle the data. In response to this method, the module should call ReadResponseBody() to read the incoming data.
[in] instance A
PP_Instanceidentifying the instance that should do the load.
[in] url_loader An open
PP_TRUEif the data was handled,
The documentation for this struct was generated from the following file: