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Pass function as an argument in a function javascript to NPAPI

On javascript Object i am invoking obj.requestFileSystem(LOCAL,5*1024*1024) . This method is implemented in PlainNAPI Plugin , now i have to pass one success callback to this function as follows......

obj.requestFileSystem(LOCAL,5*1024*1024,initFS); // initFS is a function in javascript that is an argument to the success callback . In NPAPI it is an object when the requestFileSystem is completed then initFS function in javascript should be called. How to return from NPAPI plugin to javascript and to execute initFS function.

function initFS(fs) {
alert('Inside the initFS');
alert(fs.root.getFullPath);
}
Solution

  • Please don't tell me what you're actually doing with this plugin, since it sounds like it's something akin to giving people access to things from a web browser that could easily be abused by someone else.

    Basically a function is just an NPObject when it gets to your function inside NPRuntime; to call the function you just do a NPN_InvokeDefault on that NPObject.

    Note that you must be on the main thread in order to call nearly all NPN_ functions.

    EDIT: So if you have to do the callback from a different thread then your easiest solution is to use NPN_PluginThreadAsyncCall; basically you create an object to hold the data you need and call PluginThreadAsyncCall with that pointer as the void* parameter and it will get passed to the function you specify.

    Make sure that A) the pointer will still be valid, and B) your function is able to free that memory after it runs. From the callback function you can call NPN_InvokeDefault safely.

    Not that NPN_PluginThreadAsyncCall doesn't seem to work on Safari 5.1 anymore. If you need that support or if what I've explained doesn't make sense you might want to consider using FireBreath to build your plugin; it does all of this for you.