135 lines
2.9 KiB
JavaScript
135 lines
2.9 KiB
JavaScript
'use strict';
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var util = require('util');
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var EventEmitter = require('events').EventEmitter;
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var LRU = require('lru-cache');
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var Service = function(options) {
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EventEmitter.call(this);
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this.node = options.node;
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this.name = options.name;
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};
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util.inherits(Service, EventEmitter);
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/**
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* Describes the dependencies that should be loaded before this service.
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*/
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Service.dependencies = [];
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/**
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* blockHandler
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* @param {Block} block - the block being added or removed from the chain
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* @param {Boolean} add - whether the block is being added or removed
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* @param {Function} callback - call with the leveldb database operations to perform
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*/
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Service.prototype.blockHandler = function(block, add, callback) {
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// implement in the child class
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setImmediate(function() {
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callback(null, []);
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});
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};
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/**
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* the bus events available for subscription
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* @return {Array} an array of event info
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*/
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Service.prototype.getPublishEvents = function() {
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// Example:
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// return [
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// ['eventname', this, this.subscribeEvent, this.unsubscribeEvent],
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// ];
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return [];
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};
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/**
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* the API methods to expose
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* @return {Array} return array of methods
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*/
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Service.prototype.getAPIMethods = function() {
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// Example:
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// return [
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// ['getData', this, this.getData, 1]
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// ];
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return [];
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};
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// Example:
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// Service.prototype.getData = function(arg1, callback) {
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//
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// };
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/**
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* Function which is called when module is first initialized
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*/
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Service.prototype.start = function(done) {
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setImmediate(done);
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};
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/**
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* Function to be called when bitcore-node is stopped
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*/
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Service.prototype.stop = function(done) {
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setImmediate(done);
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};
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/**
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* Setup express routes
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* @param {Express} app
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*/
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Service.prototype.setupRoutes = function() {
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// Setup express routes here
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};
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Service.prototype.getRoutePrefix = function() {
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return this.name;
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};
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Service.prototype._createConcurrencyCache = function(opts) {
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this._concurrencyCache = LRU(opts || 500);
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};
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Service.prototype._createCache = function(opts) {
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this._cache = LRU(opts || 500);
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};
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Service.prototype._retrieveCachedItems = function(key, valueItem, prevKey, fn) {
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var self = this;
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var prev = self._concurrencyCache.get(prevKey);
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if (prev && !prev.prevKey) {
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if (fn) {
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valueItem = fn.call(self, valueItem, prev.valueItem);
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}
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self._concurrencyCache.del(prevKey);
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self._concurrencyCache.set(key, { valueItem: valueItem });
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return [{ key: key, value: valueItem }];
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}
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self._concurrencyCache.set(key, { valueItem: valueItem, prevKey: prevKey });
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var resolvedDeps = [];
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var depKey = key;
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self._concurrencyCache.rforEach(function(value, key) {
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if (depKey === value.prevKey) {
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valueItem = fn.call(self, value.valueItem, depKey.valueItem);
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resolvedDeps.push({ key: key, value: valueItem });
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depKey = key;
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self._concurrencyCache.del(key);
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}
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});
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return resolvedDeps;
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};
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module.exports = Service;
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