96 lines
2.5 KiB
JavaScript
96 lines
2.5 KiB
JavaScript
// Copyright 2015-2017 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU 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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// Parity 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 General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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import BigNumber from 'bignumber.js';
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export default class Eth {
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constructor (updateSubscriptions, api) {
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this._api = api;
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this._updateSubscriptions = updateSubscriptions;
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this._started = false;
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this._lastBlock = new BigNumber(-1);
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this._pollTimerId = null;
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// Try to restart subscription if transport is closed
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this._api.transport.on('close', () => {
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if (this.isStarted) {
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this.start();
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}
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});
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}
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get isStarted () {
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return this._started;
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}
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start () {
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this._started = true;
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if (this._api.isPubSub) {
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return Promise.all([
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this._pollBlockNumber(false),
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this._api.pubsub
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.subscribeAndGetResult(
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callback => this._api.pubsub.eth.newHeads(callback),
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() => {
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return this._api.eth
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.blockNumber()
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.then(blockNumber => {
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this.updateBlock(blockNumber);
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return blockNumber;
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});
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}
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)
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]);
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}
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// fallback to polling
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return this._pollBlockNumber(true);
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}
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_pollBlockNumber = (doTimeout) => {
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const nextTimeout = (timeout = 1000, forceTimeout = doTimeout) => {
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if (forceTimeout) {
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this._pollTimerId = setTimeout(() => {
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this._pollBlockNumber(doTimeout);
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}, timeout);
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}
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};
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if (!this._api.transport.isConnected) {
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nextTimeout(500, true);
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return;
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}
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return this._api.eth
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.blockNumber()
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.then((blockNumber) => {
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this.updateBlock(blockNumber);
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nextTimeout();
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})
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.catch(() => nextTimeout());
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}
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updateBlock (blockNumber) {
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if (!blockNumber.eq(this._lastBlock)) {
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this._lastBlock = blockNumber;
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this._updateSubscriptions('eth_blockNumber', null, blockNumber);
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}
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}
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}
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