102 lines
2.9 KiB
JavaScript
102 lines
2.9 KiB
JavaScript
import Service, { inject as service } from '@ember/service';
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import MultiMap from 'mnemonist/multi-map';
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// TODO: Expose sizes of things via env vars
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// caches cursors and previous events when the EventSources are destroyed
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let cache = null;
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// keeps a record of currently in use EventSources
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let sources = null;
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// keeps a count of currently in use EventSources
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let usage = null;
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export default Service.extend({
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dom: service('dom'),
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consul: service('data-source/protocols/http'),
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settings: service('data-source/protocols/local-storage'),
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init: function() {
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this._super(...arguments);
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cache = new Map();
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sources = new Map();
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usage = new MultiMap(Set);
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this._listeners = this.dom.listeners();
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},
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resetCache: function() {
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cache = new Map();
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},
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willDestroy: function() {
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this._listeners.remove();
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sources.forEach(function(item) {
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item.close();
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});
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cache = null;
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sources = null;
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usage = null;
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},
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open: function(uri, ref, open = false) {
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let source;
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// Check the cache for an EventSource that is already being used
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// for this uri. If we don't have one, set one up.
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if (uri.indexOf('://') === -1) {
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uri = `consul://${uri}`;
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}
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if (!sources.has(uri)) {
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let [providerName, pathname] = uri.split('://');
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const provider = this[providerName];
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let configuration = {};
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if (cache.has(uri)) {
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configuration = cache.get(uri);
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}
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source = provider.source(pathname, configuration);
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this._listeners.add(source, {
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close: e => {
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const source = e.target;
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source.removeEventListener('close', close);
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const event = source.getCurrentEvent();
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const cursor = source.configuration.cursor;
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// only cache data if we have any
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if (typeof event !== 'undefined' && typeof cursor !== 'undefined') {
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cache.set(uri, {
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currentEvent: event,
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cursor: cursor,
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});
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}
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// the data is cached delete the EventSource
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if (!usage.has(source)) {
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sources.delete(uri);
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}
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},
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});
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sources.set(uri, source);
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} else {
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source = sources.get(uri);
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}
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// only open if its not already being used
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// in the case of blocking queries being disabled
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// you may want to specifically force an open
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// if blocking queries are enabled then opening an already
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// open blocking query does nothing
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if (!usage.has(source) || open) {
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source.open();
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}
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// set/increase the usage counter
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usage.set(source, ref);
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return source;
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},
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close: function(source, ref) {
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if (source) {
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// decrease the usage counter
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usage.remove(source, ref);
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// if the EventSource is no longer being used
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// close it (data caching is dealt with by the above 'close' event listener)
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if (!usage.has(source)) {
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source.close();
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}
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}
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},
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});
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