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Rudimentary multi pass dependency resolution for view models

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Largely based on a patch by @mrbeam - big thanks for that!

Conflicts:
	src/octoprint/static/js/app/main.js
This commit is contained in:
Gina Häußge 2015-02-03 22:23:32 +01:00 committed by Teja
parent 63f7b21f5b
commit 70a75863ab
1 changed files with 76 additions and 43 deletions
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119
src/octoprint/static/js/app/main.js
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@ -77,6 +77,7 @@ $(function() {
var logViewModel = new LogViewModel(loginStateViewModel);
// the view model map is our basic look up table for dependencies that may be injected into other view models
var viewModelMap = {
loginStateViewModel: loginStateViewModel,
printerProfilesViewModel: printerProfilesViewModel,
@ -96,53 +97,85 @@ $(function() {
slicingViewModel: slicingViewModel,
};
var _createViewModelInstance = function(viewModel, viewModelMap){
var viewModelClass = viewModel[0];
// helper to create a view model instance with injected constructor parameters from the view model map
var _createViewModelInstance = function(viewModel, viewModelMap){
var viewModelClass = viewModel[0];
var viewModelParameters = viewModel[1];
var constructorParameters = [];
for (var idx = 0; idx < viewModelParameters.length; idx++) {
var parameter = viewModelParameters[idx];
// now we'll try to resolve all of the view model's constructor parameters via our view model map
var constructorParameters = _.map(viewModelParameters, function(parameter){
return viewModelMap[parameter]
});
if (_.has(viewModelMap, parameter)) {
constructorParameters.push(viewModelMap[parameter]);
} else {
console.warn("postponing", viewModel[0].name, 'missing param: ', parameter);
return;
}
}
var viewModelInstance = new viewModelClass(constructorParameters);
return viewModelInstance;
};
var _getViewModelId = function(viewModel){
var name = viewModel[0].name;
return name.substr(0, 1).toLowerCase() + name.substr(1);
};
var vmtmp = ADDITIONAL_VIEWMODELS.slice();
if (_.some(constructorParameters, function(parameter) { return parameter === undefined; })) {
var _extractName = function(entry) { return entry[0]; };
var _onlyUnresolved = function(entry) { return entry[1] === undefined; };
var missingParameters = _.map(_.filter(_.zip(viewModelParameters, constructorParameters), _onlyUnresolved), _extractName);
console.log("postponing", viewModel[0].name, "due to missing parameters:", missingParameters.join(", "));
return;
}
// if we came this far then we could resolve all constructor parameters, so let's construct that view model
return new viewModelClass(constructorParameters);
};
// helper for translating the name of a view model class into an identifier for the view model map
var _getViewModelId = function(viewModel){
var name = viewModel[0].name;
return name.substr(0, 1).toLowerCase() + name.substr(1); // FooBarViewModel => fooBarViewModel
};
// instantiation loop, will make multiple passes over the list of unprocessed view models until all
// view models have been successfully instantiated with all of their dependencies or no changes can be made
// any more which means not all view models can be instantiated due to missing dependencies
var unprocessedViewModels = ADDITIONAL_VIEWMODELS.slice();
var additionalViewModels = [];
var attempt = 0;
while(vmtmp.length > 0 && attempt < 3){
while(vmtmp.length > 0){
var viewModel = vmtmp.shift();
var viewModelInstance = _createViewModelInstance(viewModel, viewModelMap);
if(viewModelInstance !== undefined){
var viewModelBindTarget = viewModel[2];
var viewModelId = _getViewModelId(viewModel);
if(viewModelMap[viewModelId] !== undefined){
console.error("Duplicate class name while instantiating viewModel ", viewModelId);
} else {
additionalViewModels.push([viewModelInstance, viewModelBindTarget]);
viewModelMap[viewModelId] = viewModelInstance;
}
} else {
vmtmp.push(viewModel);
}
}
attempt++;
}
var pass = 1;
while (unprocessedViewModels.length > 0) {
console.log("View model dependency resolution, pass #" + pass++);
var startLength = unprocessedViewModels.length;
var postponed = [];
// now try to instantiate every one of our as of yet unprocessed view model descriptors
while (unprocessedViewModels.length > 0){
var viewModel = unprocessedViewModels.shift();
var viewModelId = _getViewModelId(viewModel);
// make sure that we don't have to view models going by the same name
if (_.has(viewModelMap, viewModelId)) {
console.error("Duplicate class name while instantiating viewModel ", viewModelId);
continue;
}
var viewModelInstance = _createViewModelInstance(viewModel, viewModelMap);
// our view model couldn't yet be instantiated, so postpone it for a bit
if (viewModelInstance === undefined) {
postponed.push(viewModel);
continue;
}
// we could resolve the depdendencies and the view model is not defined yet => add it, it's now fully processed
var viewModelBindTarget = viewModel[2];
additionalViewModels.push([viewModelInstance, viewModelBindTarget]);
viewModelMap[viewModelId] = viewModelInstance;
}
// anything that's now in the postponed list has to be readded to the unprocessedViewModels
unprocessedViewModels = unprocessedViewModels.concat(postponed);
// if we still have the same amount of items in our list of unprocessed view models it means that we
// couldn't instantiate any more view models over a whole iteration, which in turn mean we can't resolve the
// dependencies of remaining ones, so log that as an error and then quit the loop
if (unprocessedViewModels.length == startLength) {
console.error("Could not instantiate the following view models due to unresolvable dependencies:");
_.each(unprocessedViewModels, function(entry) {
console.error(entry[0].name, "(missing:", _.filter(entry[1], function(id) { return !_.has(viewModelMap, id); }).join(", "), ")");
});
break;
}
}
console.log("View model dependency resolution done");
var allViewModels = _.values(viewModelMap);
var dataUpdater = new DataUpdater(allViewModels);