136 lines
4.1 KiB
JavaScript
136 lines
4.1 KiB
JavaScript
/*
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Copyright 2019 The Matrix.org Foundation C.I.C.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import DocumentOffset from "./offset";
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export default class DocumentPosition {
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constructor(index, offset) {
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this._index = index;
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this._offset = offset;
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}
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get index() {
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return this._index;
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}
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get offset() {
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return this._offset;
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}
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compare(otherPos) {
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if (this._index === otherPos._index) {
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return this._offset - otherPos._offset;
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} else {
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return this._index - otherPos._index;
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}
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}
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iteratePartsBetween(other, model, callback) {
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if (this.index === -1 || other.index === -1) {
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return;
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}
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const [startPos, endPos] = this.compare(other) < 0 ? [this, other] : [other, this];
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if (startPos.index === endPos.index) {
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callback(model.parts[this.index], startPos.offset, endPos.offset);
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} else {
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const firstPart = model.parts[startPos.index];
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callback(firstPart, startPos.offset, firstPart.text.length);
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for (let i = startPos.index + 1; i < endPos.index; ++i) {
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const part = model.parts[i];
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callback(part, 0, part.text.length);
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}
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const lastPart = model.parts[endPos.index];
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callback(lastPart, 0, endPos.offset);
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}
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}
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forwardsWhile(model, predicate) {
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if (this.index === -1) {
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return this;
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}
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let {index, offset} = this;
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const {parts} = model;
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while (index < parts.length) {
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const part = parts[index];
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while (offset < part.text.length) {
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if (!predicate(index, offset, part)) {
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return new DocumentPosition(index, offset);
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}
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offset += 1;
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}
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// end reached
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if (index === (parts.length - 1)) {
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return new DocumentPosition(index, offset);
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} else {
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index += 1;
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offset = 0;
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}
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}
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}
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backwardsWhile(model, predicate) {
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if (this.index === -1) {
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return this;
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}
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let {index, offset} = this;
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const parts = model.parts;
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while (index >= 0) {
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const part = parts[index];
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while (offset > 0) {
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if (!predicate(index, offset - 1, part)) {
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return new DocumentPosition(index, offset);
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}
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offset -= 1;
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}
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// start reached
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if (index === 0) {
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return new DocumentPosition(index, offset);
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} else {
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index -= 1;
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offset = parts[index].text.length;
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}
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}
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}
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asOffset(model) {
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if (this.index === -1) {
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return new DocumentOffset(0, true);
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}
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let offset = 0;
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for (let i = 0; i < this.index; ++i) {
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offset += model.parts[i].text.length;
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}
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offset += this.offset;
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const lastPart = model.parts[this.index];
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const atEnd = !lastPart || offset >= lastPart.text.length; // if no last part, we're at the end
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return new DocumentOffset(offset, atEnd);
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}
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isAtEnd(model) {
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if (model.parts.length === 0) {
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return true;
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}
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const lastPartIdx = model.parts.length - 1;
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const lastPart = model.parts[lastPartIdx];
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return this.index === lastPartIdx && this.offset === lastPart.text.length;
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}
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isAtStart() {
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return this.index === 0 && this.offset === 0;
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}
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}
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