react-native/Libraries/vendor/react/core/ReactInstanceHandles.js

349 lines
10 KiB
JavaScript

/**
* Copyright 2013-2014 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @providesModule ReactInstanceHandles
* @typechecks static-only
*/
"use strict";
var ReactRootIndex = require('ReactRootIndex');
var invariant = require('invariant');
var SEPARATOR = '.';
var SEPARATOR_LENGTH = SEPARATOR.length;
/**
* Maximum depth of traversals before we consider the possibility of a bad ID.
*/
var MAX_TREE_DEPTH = 100;
/**
* Creates a DOM ID prefix to use when mounting React components.
*
* @param {number} index A unique integer
* @return {string} React root ID.
* @internal
*/
function getReactRootIDString(index) {
return SEPARATOR + index.toString(36);
}
/**
* Checks if a character in the supplied ID is a separator or the end.
*
* @param {string} id A React DOM ID.
* @param {number} index Index of the character to check.
* @return {boolean} True if the character is a separator or end of the ID.
* @private
*/
function isBoundary(id, index) {
return id.charAt(index) === SEPARATOR || index === id.length;
}
/**
* Checks if the supplied string is a valid React DOM ID.
*
* @param {string} id A React DOM ID, maybe.
* @return {boolean} True if the string is a valid React DOM ID.
* @private
*/
function isValidID(id) {
return id === '' || (
id.charAt(0) === SEPARATOR && id.charAt(id.length - 1) !== SEPARATOR
);
}
/**
* Checks if the first ID is an ancestor of or equal to the second ID.
*
* @param {string} ancestorID
* @param {string} descendantID
* @return {boolean} True if `ancestorID` is an ancestor of `descendantID`.
* @internal
*/
function isAncestorIDOf(ancestorID, descendantID) {
return (
descendantID.indexOf(ancestorID) === 0 &&
isBoundary(descendantID, ancestorID.length)
);
}
/**
* Gets the parent ID of the supplied React DOM ID, `id`.
*
* @param {string} id ID of a component.
* @return {string} ID of the parent, or an empty string.
* @private
*/
function getParentID(id) {
return id ? id.substr(0, id.lastIndexOf(SEPARATOR)) : '';
}
/**
* Gets the next DOM ID on the tree path from the supplied `ancestorID` to the
* supplied `destinationID`. If they are equal, the ID is returned.
*
* @param {string} ancestorID ID of an ancestor node of `destinationID`.
* @param {string} destinationID ID of the destination node.
* @return {string} Next ID on the path from `ancestorID` to `destinationID`.
* @private
*/
function getNextDescendantID(ancestorID, destinationID) {
invariant(
isValidID(ancestorID) && isValidID(destinationID),
'getNextDescendantID(%s, %s): Received an invalid React DOM ID.',
ancestorID,
destinationID
);
invariant(
isAncestorIDOf(ancestorID, destinationID),
'getNextDescendantID(...): React has made an invalid assumption about ' +
'the DOM hierarchy. Expected `%s` to be an ancestor of `%s`.',
ancestorID,
destinationID
);
if (ancestorID === destinationID) {
return ancestorID;
}
// Skip over the ancestor and the immediate separator. Traverse until we hit
// another separator or we reach the end of `destinationID`.
var start = ancestorID.length + SEPARATOR_LENGTH;
for (var i = start; i < destinationID.length; i++) {
if (isBoundary(destinationID, i)) {
break;
}
}
return destinationID.substr(0, i);
}
/**
* Gets the nearest common ancestor ID of two IDs.
*
* Using this ID scheme, the nearest common ancestor ID is the longest common
* prefix of the two IDs that immediately preceded a "marker" in both strings.
*
* @param {string} oneID
* @param {string} twoID
* @return {string} Nearest common ancestor ID, or the empty string if none.
* @private
*/
function getFirstCommonAncestorID(oneID, twoID) {
var minLength = Math.min(oneID.length, twoID.length);
if (minLength === 0) {
return '';
}
var lastCommonMarkerIndex = 0;
// Use `<=` to traverse until the "EOL" of the shorter string.
for (var i = 0; i <= minLength; i++) {
if (isBoundary(oneID, i) && isBoundary(twoID, i)) {
lastCommonMarkerIndex = i;
} else if (oneID.charAt(i) !== twoID.charAt(i)) {
break;
}
}
var longestCommonID = oneID.substr(0, lastCommonMarkerIndex);
invariant(
isValidID(longestCommonID),
'getFirstCommonAncestorID(%s, %s): Expected a valid React DOM ID: %s',
oneID,
twoID,
longestCommonID
);
return longestCommonID;
}
/**
* Traverses the parent path between two IDs (either up or down). The IDs must
* not be the same, and there must exist a parent path between them. If the
* callback returns `false`, traversal is stopped.
*
* @param {?string} start ID at which to start traversal.
* @param {?string} stop ID at which to end traversal.
* @param {function} cb Callback to invoke each ID with.
* @param {?boolean} skipFirst Whether or not to skip the first node.
* @param {?boolean} skipLast Whether or not to skip the last node.
* @private
*/
function traverseParentPath(start, stop, cb, arg, skipFirst, skipLast) {
start = start || '';
stop = stop || '';
invariant(
start !== stop,
'traverseParentPath(...): Cannot traverse from and to the same ID, `%s`.',
start
);
var traverseUp = isAncestorIDOf(stop, start);
invariant(
traverseUp || isAncestorIDOf(start, stop),
'traverseParentPath(%s, %s, ...): Cannot traverse from two IDs that do ' +
'not have a parent path.',
start,
stop
);
// Traverse from `start` to `stop` one depth at a time.
var depth = 0;
var traverse = traverseUp ? getParentID : getNextDescendantID;
for (var id = start; /* until break */; id = traverse(id, stop)) {
var ret;
if ((!skipFirst || id !== start) && (!skipLast || id !== stop)) {
ret = cb(id, traverseUp, arg);
}
if (ret === false || id === stop) {
// Only break //after// visiting `stop`.
break;
}
invariant(
depth++ < MAX_TREE_DEPTH,
'traverseParentPath(%s, %s, ...): Detected an infinite loop while ' +
'traversing the React DOM ID tree. This may be due to malformed IDs: %s',
start, stop
);
}
}
/**
* Manages the IDs assigned to DOM representations of React components. This
* uses a specific scheme in order to traverse the DOM efficiently (e.g. in
* order to simulate events).
*
* @internal
*/
var ReactInstanceHandles = {
/**
* Constructs a React root ID
* @return {string} A React root ID.
*/
createReactRootID: function() {
return getReactRootIDString(ReactRootIndex.createReactRootIndex());
},
/**
* Constructs a React ID by joining a root ID with a name.
*
* @param {string} rootID Root ID of a parent component.
* @param {string} name A component's name (as flattened children).
* @return {string} A React ID.
* @internal
*/
createReactID: function(rootID, name) {
return rootID + name;
},
/**
* Gets the DOM ID of the React component that is the root of the tree that
* contains the React component with the supplied DOM ID.
*
* @param {string} id DOM ID of a React component.
* @return {?string} DOM ID of the React component that is the root.
* @internal
*/
getReactRootIDFromNodeID: function(id) {
if (id && id.charAt(0) === SEPARATOR && id.length > 1) {
var index = id.indexOf(SEPARATOR, 1);
return index > -1 ? id.substr(0, index) : id;
}
return null;
},
/**
* Traverses the ID hierarchy and invokes the supplied `cb` on any IDs that
* should would receive a `mouseEnter` or `mouseLeave` event.
*
* NOTE: Does not invoke the callback on the nearest common ancestor because
* nothing "entered" or "left" that element.
*
* @param {string} leaveID ID being left.
* @param {string} enterID ID being entered.
* @param {function} cb Callback to invoke on each entered/left ID.
* @param {*} upArg Argument to invoke the callback with on left IDs.
* @param {*} downArg Argument to invoke the callback with on entered IDs.
* @internal
*/
traverseEnterLeave: function(leaveID, enterID, cb, upArg, downArg) {
var ancestorID = getFirstCommonAncestorID(leaveID, enterID);
if (ancestorID !== leaveID) {
traverseParentPath(leaveID, ancestorID, cb, upArg, false, true);
}
if (ancestorID !== enterID) {
traverseParentPath(ancestorID, enterID, cb, downArg, true, false);
}
},
/**
* Simulates the traversal of a two-phase, capture/bubble event dispatch.
*
* NOTE: This traversal happens on IDs without touching the DOM.
*
* @param {string} targetID ID of the target node.
* @param {function} cb Callback to invoke.
* @param {*} arg Argument to invoke the callback with.
* @internal
*/
traverseTwoPhase: function(targetID, cb, arg) {
if (targetID) {
traverseParentPath('', targetID, cb, arg, true, false);
traverseParentPath(targetID, '', cb, arg, false, true);
}
},
/**
* Same as `traverseTwoPhase` but skips the `targetID`.
*/
traverseTwoPhaseSkipTarget: function(targetID, cb, arg) {
if (targetID) {
traverseParentPath('', targetID, cb, arg, true, true);
traverseParentPath(targetID, '', cb, arg, true, true);
}
},
/**
* Traverse a node ID, calling the supplied `cb` for each ancestor ID. For
* example, passing `.0.$row-0.1` would result in `cb` getting called
* with `.0`, `.0.$row-0`, and `.0.$row-0.1`.
*
* NOTE: This traversal happens on IDs without touching the DOM.
*
* @param {string} targetID ID of the target node.
* @param {function} cb Callback to invoke.
* @param {*} arg Argument to invoke the callback with.
* @internal
*/
traverseAncestors: function(targetID, cb, arg) {
traverseParentPath('', targetID, cb, arg, true, false);
},
/**
* Exposed for unit testing.
* @private
*/
_getFirstCommonAncestorID: getFirstCommonAncestorID,
/**
* Exposed for unit testing.
* @private
*/
_getNextDescendantID: getNextDescendantID,
isAncestorIDOf: isAncestorIDOf,
SEPARATOR: SEPARATOR
};
module.exports = ReactInstanceHandles;