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Diffstat (limited to 'node_modules/react-dom/lib/Transaction.js')
| -rw-r--r-- | node_modules/react-dom/lib/Transaction.js | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/node_modules/react-dom/lib/Transaction.js b/node_modules/react-dom/lib/Transaction.js new file mode 100644 index 000000000..565e55a0a --- /dev/null +++ b/node_modules/react-dom/lib/Transaction.js @@ -0,0 +1,224 @@ +/** + * Copyright 2013-present, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under the BSD-style license found in the + * LICENSE file in the root directory of this source tree. An additional grant + * of patent rights can be found in the PATENTS file in the same directory. + * + * + */ + +'use strict'; + +var _prodInvariant = require('./reactProdInvariant'); + +var invariant = require('fbjs/lib/invariant'); + +var OBSERVED_ERROR = {}; + +/** + * `Transaction` creates a black box that is able to wrap any method such that + * certain invariants are maintained before and after the method is invoked + * (Even if an exception is thrown while invoking the wrapped method). Whoever + * instantiates a transaction can provide enforcers of the invariants at + * creation time. The `Transaction` class itself will supply one additional + * automatic invariant for you - the invariant that any transaction instance + * should not be run while it is already being run. You would typically create a + * single instance of a `Transaction` for reuse multiple times, that potentially + * is used to wrap several different methods. Wrappers are extremely simple - + * they only require implementing two methods. + * + * <pre> + * wrappers (injected at creation time) + * + + + * | | + * +-----------------|--------|--------------+ + * | v | | + * | +---------------+ | | + * | +--| wrapper1 |---|----+ | + * | | +---------------+ v | | + * | | +-------------+ | | + * | | +----| wrapper2 |--------+ | + * | | | +-------------+ | | | + * | | | | | | + * | v v v v | wrapper + * | +---+ +---+ +---------+ +---+ +---+ | invariants + * perform(anyMethod) | | | | | | | | | | | | maintained + * +----------------->|-|---|-|---|-->|anyMethod|---|---|-|---|-|--------> + * | | | | | | | | | | | | + * | | | | | | | | | | | | + * | | | | | | | | | | | | + * | +---+ +---+ +---------+ +---+ +---+ | + * | initialize close | + * +-----------------------------------------+ + * </pre> + * + * Use cases: + * - Preserving the input selection ranges before/after reconciliation. + * Restoring selection even in the event of an unexpected error. + * - Deactivating events while rearranging the DOM, preventing blurs/focuses, + * while guaranteeing that afterwards, the event system is reactivated. + * - Flushing a queue of collected DOM mutations to the main UI thread after a + * reconciliation takes place in a worker thread. + * - Invoking any collected `componentDidUpdate` callbacks after rendering new + * content. + * - (Future use case): Wrapping particular flushes of the `ReactWorker` queue + * to preserve the `scrollTop` (an automatic scroll aware DOM). + * - (Future use case): Layout calculations before and after DOM updates. + * + * Transactional plugin API: + * - A module that has an `initialize` method that returns any precomputation. + * - and a `close` method that accepts the precomputation. `close` is invoked + * when the wrapped process is completed, or has failed. + * + * @param {Array<TransactionalWrapper>} transactionWrapper Wrapper modules + * that implement `initialize` and `close`. + * @return {Transaction} Single transaction for reuse in thread. + * + * @class Transaction + */ +var TransactionImpl = { + /** + * Sets up this instance so that it is prepared for collecting metrics. Does + * so such that this setup method may be used on an instance that is already + * initialized, in a way that does not consume additional memory upon reuse. + * That can be useful if you decide to make your subclass of this mixin a + * "PooledClass". + */ + reinitializeTransaction: function () { + this.transactionWrappers = this.getTransactionWrappers(); + if (this.wrapperInitData) { + this.wrapperInitData.length = 0; + } else { + this.wrapperInitData = []; + } + this._isInTransaction = false; + }, + + _isInTransaction: false, + + /** + * @abstract + * @return {Array<TransactionWrapper>} Array of transaction wrappers. + */ + getTransactionWrappers: null, + + isInTransaction: function () { + return !!this._isInTransaction; + }, + + /** + * Executes the function within a safety window. Use this for the top level + * methods that result in large amounts of computation/mutations that would + * need to be safety checked. The optional arguments helps prevent the need + * to bind in many cases. + * + * @param {function} method Member of scope to call. + * @param {Object} scope Scope to invoke from. + * @param {Object?=} a Argument to pass to the method. + * @param {Object?=} b Argument to pass to the method. + * @param {Object?=} c Argument to pass to the method. + * @param {Object?=} d Argument to pass to the method. + * @param {Object?=} e Argument to pass to the method. + * @param {Object?=} f Argument to pass to the method. + * + * @return {*} Return value from `method`. + */ + perform: function (method, scope, a, b, c, d, e, f) { + !!this.isInTransaction() ? process.env.NODE_ENV !== 'production' ? invariant(false, 'Transaction.perform(...): Cannot initialize a transaction when there is already an outstanding transaction.') : _prodInvariant('27') : void 0; + var errorThrown; + var ret; + try { + this._isInTransaction = true; + // Catching errors makes debugging more difficult, so we start with + // errorThrown set to true before setting it to false after calling + // close -- if it's still set to true in the finally block, it means + // one of these calls threw. + errorThrown = true; + this.initializeAll(0); + ret = method.call(scope, a, b, c, d, e, f); + errorThrown = false; + } finally { + try { + if (errorThrown) { + // If `method` throws, prefer to show that stack trace over any thrown + // by invoking `closeAll`. + try { + this.closeAll(0); + } catch (err) {} + } else { + // Since `method` didn't throw, we don't want to silence the exception + // here. + this.closeAll(0); + } + } finally { + this._isInTransaction = false; + } + } + return ret; + }, + + initializeAll: function (startIndex) { + var transactionWrappers = this.transactionWrappers; + for (var i = startIndex; i < transactionWrappers.length; i++) { + var wrapper = transactionWrappers[i]; + try { + // Catching errors makes debugging more difficult, so we start with the + // OBSERVED_ERROR state before overwriting it with the real return value + // of initialize -- if it's still set to OBSERVED_ERROR in the finally + // block, it means wrapper.initialize threw. + this.wrapperInitData[i] = OBSERVED_ERROR; + this.wrapperInitData[i] = wrapper.initialize ? wrapper.initialize.call(this) : null; + } finally { + if (this.wrapperInitData[i] === OBSERVED_ERROR) { + // The initializer for wrapper i threw an error; initialize the + // remaining wrappers but silence any exceptions from them to ensure + // that the first error is the one to bubble up. + try { + this.initializeAll(i + 1); + } catch (err) {} + } + } + } + }, + + /** + * Invokes each of `this.transactionWrappers.close[i]` functions, passing into + * them the respective return values of `this.transactionWrappers.init[i]` + * (`close`rs that correspond to initializers that failed will not be + * invoked). + */ + closeAll: function (startIndex) { + !this.isInTransaction() ? process.env.NODE_ENV !== 'production' ? invariant(false, 'Transaction.closeAll(): Cannot close transaction when none are open.') : _prodInvariant('28') : void 0; + var transactionWrappers = this.transactionWrappers; + for (var i = startIndex; i < transactionWrappers.length; i++) { + var wrapper = transactionWrappers[i]; + var initData = this.wrapperInitData[i]; + var errorThrown; + try { + // Catching errors makes debugging more difficult, so we start with + // errorThrown set to true before setting it to false after calling + // close -- if it's still set to true in the finally block, it means + // wrapper.close threw. + errorThrown = true; + if (initData !== OBSERVED_ERROR && wrapper.close) { + wrapper.close.call(this, initData); + } + errorThrown = false; + } finally { + if (errorThrown) { + // The closer for wrapper i threw an error; close the remaining + // wrappers but silence any exceptions from them to ensure that the + // first error is the one to bubble up. + try { + this.closeAll(i + 1); + } catch (e) {} + } + } + } + this.wrapperInitData.length = 0; + } +}; + +module.exports = TransactionImpl;
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