Chris@4: "use strict";
Chris@4: 
Chris@28: var exampleModule = VampExamplePluginsModule();
Chris@4: 
Chris@4: // It is possible to declare both parameters and return values as
Chris@4: // "string", in which case Emscripten will take care of
Chris@4: // conversions. But it's not clear how one would manage memory for
Chris@4: // newly-constructed returned C strings -- the returned pointer from
Chris@43: // piperRequestJson would appear (?) to be thrown away by the
Chris@4: // Emscripten string converter if we declare it as returning a string,
Chris@43: // so we have no opportunity to pass it to piperFreeJson, which
Chris@4: // suggests this would leak memory if the string isn't static. Not
Chris@4: // wholly sure though. Anyway, passing and returning pointers (as
Chris@4: // numbers) means we can manage the Emscripten heap memory however we
Chris@4: // want in our request wrapper function below.
Chris@4: 
Chris@43: var piperRequestJson = exampleModule.cwrap(
Chris@43:     'piperRequestJson', 'number', ['number']
Chris@4: );
Chris@4: 
Chris@43: var piperFreeJson = exampleModule.cwrap(
Chris@43:     'piperFreeJson', 'void', ['number']
Chris@4: );
Chris@4: 
Chris@6: function note(blah) {
Chris@6:     document.getElementById("test-result").innerHTML += blah + "<br>";
Chris@6: }
Chris@6: 
Chris@6: function comment(blah) {
Chris@6:     note("<br><i>" + blah + "</i>");
Chris@6: }
Chris@6: 
Chris@4: function request(jsonStr) {
Chris@6:     note("Request JSON = " + jsonStr);
Chris@4:     var m = exampleModule;
Chris@4:     // Inspection reveals that intArrayFromString converts the string
Chris@4:     // from utf16 to utf8, which is what we want (though the docs
Chris@4:     // don't mention this). Note the *Cstr values are Emscripten heap
Chris@4:     // pointers
Chris@4:     var inCstr = m.allocate(m.intArrayFromString(jsonStr), 'i8', m.ALLOC_NORMAL);
Chris@43:     var outCstr = piperRequestJson(inCstr);
Chris@4:     m._free(inCstr);
Chris@4:     var result = m.Pointer_stringify(outCstr);
Chris@43:     piperFreeJson(outCstr);
Chris@6:     note("Returned JSON = " + result);
Chris@4:     return result;
Chris@4: }
Chris@4: 
Chris@4: function test() {
Chris@4: 
Chris@6:     comment("Querying plugin list...");
Chris@40:     var result = request('{"method": "list"}');
Chris@4: 
Chris@6:     comment("Loading zero crossings plugin...");
Chris@40:     result = request('{"method":"load","params": {"key":"vamp-example-plugins:powerspectrum","inputSampleRate":16,"adapterFlags":["AdaptAllSafe"]}}');
Chris@4: 
Chris@40:     comment("I'm now assuming that the load succeeded and the returned handle was 1. I haven't bothered to parse the JSON. If those assumptions are wrong, this obviously isn't going to work. Configuring the plugin...");
Chris@40:     result = request('{"method":"configure","params":{"handle":1,"configuration":{"blockSize": 8, "channelCount": 1, "stepSize": 8}}}');
Chris@4: 
Chris@6:     comment("If I try to configure it again, it should fail because it's already configured... but this doesn't change anything, and subsequent processing should work fine. Just an example of a failure call. NB this only works if Emscripten has exception catching enabled -- it's off by default in opt builds, which would just end the script here. Wonder what the performance penalty is like.");
Chris@40:     result = request('{"method":"configure","params":{"handle":1,"configuration":{"blockSize": 8, "channelCount": 1, "stepSize": 8}}}');
Chris@4: 
Chris@6:     comment("Now processing a couple of blocks of data, on the same assumptions...");
Chris@40:     result = request('{"method":"process","params":{"handle":1,"processInput":{"timestamp":{"s":0,"n":0},"inputBuffers":[[0,1,-1,0,1,-1,0,1]]}}}');
Chris@40:     result = request('{"method":"process","params":{"handle":1,"processInput":{"timestamp":{"s":0,"n":500000000},"inputBuffers":[[0,1,-1,0,1,-1,0,1]]}}}');
Chris@4: 
Chris@6:     comment("Cleaning up the plugin and getting any remaining features...");
Chris@40:     result = request('{"method":"finish","params":{"handle":1}}');
Chris@4: 
Chris@6:     comment("A process call should now fail, as the plugin has been cleaned up.");
Chris@40:     result = request('{"method":"process","params":{"handle":1,"processInput":{"timestamp":{"s":0,"n":1000000000},"inputBuffers":[{"values":[0,1,-1,0,1,-1,0,1]}]}}}');
Chris@4: }
Chris@4: 
Chris@4: window.onload = function() {
Chris@4:     test();
Chris@4: }