mirror of https://github.com/status-im/web3.js.git
114 lines
3.5 KiB
JavaScript
114 lines
3.5 KiB
JavaScript
/*
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This file is part of ethereum.js.
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ethereum.js is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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ethereum.js is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with ethereum.js. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file filter.js
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* @authors:
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* Jeffrey Wilcke <jeff@ethdev.com>
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* Marek Kotewicz <marek@ethdev.com>
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* Marian Oancea <marian@ethdev.com>
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* Gav Wood <g@ethdev.com>
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* @date 2014
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*/
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/// Should be called to check if filter implementation is valid
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/// @returns true if it is, otherwise false
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var implementationIsValid = function (i) {
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return !!i &&
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typeof i.newFilter === 'function' &&
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typeof i.getMessages === 'function' &&
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typeof i.uninstallFilter === 'function' &&
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typeof i.startPolling === 'function' &&
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typeof i.stopPolling === 'function';
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};
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/// This method should be called on options object, to verify deprecated properties && lazy load dynamic ones
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/// @param should be string or object
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/// @returns options string or object
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var getOptions = function (options) {
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if (typeof options === 'string') {
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return options;
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}
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options = options || {};
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if (options.topics) {
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console.warn('"topics" is deprecated, is "topic" instead');
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}
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// evaluate lazy properties
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return {
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to: options.to,
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topic: options.topic,
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earliest: options.earliest,
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latest: options.latest,
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max: options.max,
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skip: options.skip,
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address: options.address
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};
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};
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/// Should be used when we want to watch something
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/// it's using inner polling mechanism and is notified about changes
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/// @param options are filter options
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/// @param implementation, an abstract polling implementation
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/// @param formatter (optional), callback function which formats output before 'real' callback
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var filter = function(options, implementation, formatter) {
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if (!implementationIsValid(implementation)) {
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console.error('filter implemenation is invalid');
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return;
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}
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options = getOptions(options);
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var callbacks = [];
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var filterId = implementation.newFilter(options);
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var onMessages = function (messages) {
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messages.forEach(function (message) {
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message = formatter ? formatter(message) : message;
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callbacks.forEach(function (callback) {
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callback(message);
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});
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});
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};
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implementation.startPolling(filterId, onMessages, implementation.uninstallFilter);
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var changed = function (callback) {
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callbacks.push(callback);
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};
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var messages = function () {
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return implementation.getMessages(filterId);
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};
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var uninstall = function (callback) {
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implementation.stopPolling(filterId);
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implementation.uninstallFilter(filterId);
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callbacks = [];
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};
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return {
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changed: changed,
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arrived: changed,
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happened: changed,
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messages: messages,
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logs: messages,
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uninstall: uninstall
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};
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};
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module.exports = filter;
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