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Copy pathtextChange.ts
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344 lines (285 loc) · 9.11 KB
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/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
import * as buffer from 'vs/base/common/buffer';
import { decodeUTF16LE } from 'vs/editor/common/core/stringBuilder';
function escapeNewLine(str: string): string {
return (
str
.replace(/\n/g, '\\n')
.replace(/\r/g, '\\r')
);
}
export class TextChange {
public get oldLength(): number {
return this.oldText.length;
}
public get oldEnd(): number {
return this.oldPosition + this.oldText.length;
}
public get newLength(): number {
return this.newText.length;
}
public get newEnd(): number {
return this.newPosition + this.newText.length;
}
constructor(
public readonly oldPosition: number,
public readonly oldText: string,
public readonly newPosition: number,
public readonly newText: string
) { }
public toString(): string {
if (this.oldText.length === 0) {
return `(insert@${this.oldPosition} "${escapeNewLine(this.newText)}")`;
}
if (this.newText.length === 0) {
return `(delete@${this.oldPosition} "${escapeNewLine(this.oldText)}")`;
}
return `(replace@${this.oldPosition} "${escapeNewLine(this.oldText)}" with "${escapeNewLine(this.newText)}")`;
}
private static _writeStringSize(str: string): number {
return (
4 + 2 * str.length
);
}
private static _writeString(b: Uint8Array, str: string, offset: number): number {
const len = str.length;
buffer.writeUInt32BE(b, len, offset); offset += 4;
for (let i = 0; i < len; i++) {
buffer.writeUInt16LE(b, str.charCodeAt(i), offset); offset += 2;
}
return offset;
}
private static _readString(b: Uint8Array, offset: number): string {
const len = buffer.readUInt32BE(b, offset); offset += 4;
return decodeUTF16LE(b, offset, len);
}
public writeSize(): number {
return (
+ 4 // oldPosition
+ 4 // newPosition
+ TextChange._writeStringSize(this.oldText)
+ TextChange._writeStringSize(this.newText)
);
}
public write(b: Uint8Array, offset: number): number {
buffer.writeUInt32BE(b, this.oldPosition, offset); offset += 4;
buffer.writeUInt32BE(b, this.newPosition, offset); offset += 4;
offset = TextChange._writeString(b, this.oldText, offset);
offset = TextChange._writeString(b, this.newText, offset);
return offset;
}
public static read(b: Uint8Array, offset: number, dest: TextChange[]): number {
const oldPosition = buffer.readUInt32BE(b, offset); offset += 4;
const newPosition = buffer.readUInt32BE(b, offset); offset += 4;
const oldText = TextChange._readString(b, offset); offset += TextChange._writeStringSize(oldText);
const newText = TextChange._readString(b, offset); offset += TextChange._writeStringSize(newText);
dest.push(new TextChange(oldPosition, oldText, newPosition, newText));
return offset;
}
}
export function compressConsecutiveTextChanges(prevEdits: TextChange[] | null, currEdits: TextChange[]): TextChange[] {
if (prevEdits === null || prevEdits.length === 0) {
return currEdits;
}
const compressor = new TextChangeCompressor(prevEdits, currEdits);
return compressor.compress();
}
class TextChangeCompressor {
private _prevEdits: TextChange[];
private _currEdits: TextChange[];
private _result: TextChange[];
private _resultLen: number;
private _prevLen: number;
private _prevDeltaOffset: number;
private _currLen: number;
private _currDeltaOffset: number;
constructor(prevEdits: TextChange[], currEdits: TextChange[]) {
this._prevEdits = prevEdits;
this._currEdits = currEdits;
this._result = [];
this._resultLen = 0;
this._prevLen = this._prevEdits.length;
this._prevDeltaOffset = 0;
this._currLen = this._currEdits.length;
this._currDeltaOffset = 0;
}
public compress(): TextChange[] {
let prevIndex = 0;
let currIndex = 0;
let prevEdit = this._getPrev(prevIndex);
let currEdit = this._getCurr(currIndex);
while (prevIndex < this._prevLen || currIndex < this._currLen) {
if (prevEdit === null) {
this._acceptCurr(currEdit!);
currEdit = this._getCurr(++currIndex);
continue;
}
if (currEdit === null) {
this._acceptPrev(prevEdit);
prevEdit = this._getPrev(++prevIndex);
continue;
}
if (currEdit.oldEnd <= prevEdit.newPosition) {
this._acceptCurr(currEdit);
currEdit = this._getCurr(++currIndex);
continue;
}
if (prevEdit.newEnd <= currEdit.oldPosition) {
this._acceptPrev(prevEdit);
prevEdit = this._getPrev(++prevIndex);
continue;
}
if (currEdit.oldPosition < prevEdit.newPosition) {
const [e1, e2] = TextChangeCompressor._splitCurr(currEdit, prevEdit.newPosition - currEdit.oldPosition);
this._acceptCurr(e1);
currEdit = e2;
continue;
}
if (prevEdit.newPosition < currEdit.oldPosition) {
const [e1, e2] = TextChangeCompressor._splitPrev(prevEdit, currEdit.oldPosition - prevEdit.newPosition);
this._acceptPrev(e1);
prevEdit = e2;
continue;
}
// At this point, currEdit.oldPosition === prevEdit.newPosition
let mergePrev: TextChange;
let mergeCurr: TextChange;
if (currEdit.oldEnd === prevEdit.newEnd) {
mergePrev = prevEdit;
mergeCurr = currEdit;
prevEdit = this._getPrev(++prevIndex);
currEdit = this._getCurr(++currIndex);
} else if (currEdit.oldEnd < prevEdit.newEnd) {
const [e1, e2] = TextChangeCompressor._splitPrev(prevEdit, currEdit.oldLength);
mergePrev = e1;
mergeCurr = currEdit;
prevEdit = e2;
currEdit = this._getCurr(++currIndex);
} else {
const [e1, e2] = TextChangeCompressor._splitCurr(currEdit, prevEdit.newLength);
mergePrev = prevEdit;
mergeCurr = e1;
prevEdit = this._getPrev(++prevIndex);
currEdit = e2;
}
this._result[this._resultLen++] = new TextChange(
mergePrev.oldPosition,
mergePrev.oldText,
mergeCurr.newPosition,
mergeCurr.newText
);
this._prevDeltaOffset += mergePrev.newLength - mergePrev.oldLength;
this._currDeltaOffset += mergeCurr.newLength - mergeCurr.oldLength;
}
const merged = TextChangeCompressor._merge(this._result);
const cleaned = TextChangeCompressor._removeNoOps(merged);
return cleaned;
}
private _acceptCurr(currEdit: TextChange): void {
this._result[this._resultLen++] = TextChangeCompressor._rebaseCurr(this._prevDeltaOffset, currEdit);
this._currDeltaOffset += currEdit.newLength - currEdit.oldLength;
}
private _getCurr(currIndex: number): TextChange | null {
return (currIndex < this._currLen ? this._currEdits[currIndex] : null);
}
private _acceptPrev(prevEdit: TextChange): void {
this._result[this._resultLen++] = TextChangeCompressor._rebasePrev(this._currDeltaOffset, prevEdit);
this._prevDeltaOffset += prevEdit.newLength - prevEdit.oldLength;
}
private _getPrev(prevIndex: number): TextChange | null {
return (prevIndex < this._prevLen ? this._prevEdits[prevIndex] : null);
}
private static _rebaseCurr(prevDeltaOffset: number, currEdit: TextChange): TextChange {
return new TextChange(
currEdit.oldPosition - prevDeltaOffset,
currEdit.oldText,
currEdit.newPosition,
currEdit.newText
);
}
private static _rebasePrev(currDeltaOffset: number, prevEdit: TextChange): TextChange {
return new TextChange(
prevEdit.oldPosition,
prevEdit.oldText,
prevEdit.newPosition + currDeltaOffset,
prevEdit.newText
);
}
private static _splitPrev(edit: TextChange, offset: number): [TextChange, TextChange] {
const preText = edit.newText.substr(0, offset);
const postText = edit.newText.substr(offset);
return [
new TextChange(
edit.oldPosition,
edit.oldText,
edit.newPosition,
preText
),
new TextChange(
edit.oldEnd,
'',
edit.newPosition + offset,
postText
)
];
}
private static _splitCurr(edit: TextChange, offset: number): [TextChange, TextChange] {
const preText = edit.oldText.substr(0, offset);
const postText = edit.oldText.substr(offset);
return [
new TextChange(
edit.oldPosition,
preText,
edit.newPosition,
edit.newText
),
new TextChange(
edit.oldPosition + offset,
postText,
edit.newEnd,
''
)
];
}
private static _merge(edits: TextChange[]): TextChange[] {
if (edits.length === 0) {
return edits;
}
let result: TextChange[] = [], resultLen = 0;
let prev = edits[0];
for (let i = 1; i < edits.length; i++) {
const curr = edits[i];
if (prev.oldEnd === curr.oldPosition) {
// Merge into `prev`
prev = new TextChange(
prev.oldPosition,
prev.oldText + curr.oldText,
prev.newPosition,
prev.newText + curr.newText
);
} else {
result[resultLen++] = prev;
prev = curr;
}
}
result[resultLen++] = prev;
return result;
}
private static _removeNoOps(edits: TextChange[]): TextChange[] {
if (edits.length === 0) {
return edits;
}
let result: TextChange[] = [], resultLen = 0;
for (let i = 0; i < edits.length; i++) {
const edit = edits[i];
if (edit.oldText === edit.newText) {
continue;
}
result[resultLen++] = edit;
}
return result;
}
}