Moved more files to typescript

src/static/js/undomodule.ts

@@ -0,0 +1,275 @@
+'use strict';
+
+/**
+ * This code is mostly from the old Etherpad. Please help us to comment this code.
+ * This helps other people to understand this code better and helps them to improve it.
+ * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
+ */
+
+import {RepModel} from "./types/RepModel";
+
+/**
+ * Copyright 2009 Google 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.
+ */
+
+const Changeset = require('./Changeset');
+import {extend} from 'underscore'
+import AttributePool from "./AttributePool";
+
+export let pool: AttributePool|null = null
+
+
+export const setPool = (poolAssigned: AttributePool)=> {
+  pool = poolAssigned
+}
+class Stack {
+  private numUndoableEvents = 0
+  private UNDOABLE_EVENT = 'undoableEvent';
+  private EXTERNAL_CHANGE = 'externalChange';
+  private stackElements: any[] = []
+
+  constructor() {
+    // two types of stackElements:
+    // 1) { elementType: UNDOABLE_EVENT, eventType: "anything", [backset: <changeset>,]
+    //      [selStart: <char number>, selEnd: <char number>, selFocusAtStart: <boolean>] }
+    // 2) { elementType: EXTERNAL_CHANGE, changeset: <changeset> }
+    // invariant: no two consecutive EXTERNAL_CHANGEs
+    this.clearStack();
+  }
+  clearStack = () => {
+    this.stackElements.length = 0;
+    this.stackElements.push(
+      {
+        elementType: this.UNDOABLE_EVENT,
+        eventType: 'bottom',
+      });
+    this.numUndoableEvents = 1;
+  };
+  pushEvent = (event: string) => {
+    const e = extend(
+      {}, event);
+    e.elementType = this.UNDOABLE_EVENT;
+    this.stackElements.push(e);
+    this.numUndoableEvents++;
+  }
+  pushExternalChange = (cs: string) => {
+    const idx = this.stackElements.length - 1;
+    if (this.stackElements[idx].elementType === this.EXTERNAL_CHANGE) {
+      this.stackElements[idx].changeset =
+        Changeset.compose(this.stackElements[idx].changeset, cs, pool);
+    } else {
+      this.stackElements.push(
+        {
+          elementType: this.EXTERNAL_CHANGE,
+          changeset: cs,
+        });
+    }
+  }
+
+  private exposeEvent = (nthFromTop: number) => {
+    // precond: 0 <= nthFromTop < numUndoableEvents
+    const targetIndex = this.stackElements.length - 1 - nthFromTop;
+    let idx = this.stackElements.length - 1;
+    while (idx > targetIndex || this.stackElements[idx].elementType === this.EXTERNAL_CHANGE) {
+      if (this.stackElements[idx].elementType === this.EXTERNAL_CHANGE) {
+        const ex = this.stackElements[idx];
+        const un = this.stackElements[idx - 1];
+        if (un.backset) {
+          const excs = ex.changeset;
+          const unbs = un.backset;
+          un.backset = Changeset.follow(excs, un.backset, false, pool);
+          ex.changeset = Changeset.follow(unbs, ex.changeset, true, pool);
+          if ((typeof un.selStart) === 'number') {
+            const newSel = Changeset.characterRangeFollow(excs, un.selStart, un.selEnd);
+            un.selStart = newSel[0];
+            un.selEnd = newSel[1];
+            if (un.selStart === un.selEnd) {
+              un.selFocusAtStart = false;
+            }
+          }
+        }
+        this.stackElements[idx - 1] = ex;
+        this.stackElements[idx] = un;
+        if (idx >= 2 && this.stackElements[idx - 2].elementType === this.EXTERNAL_CHANGE) {
+          ex.changeset =
+            Changeset.compose(this.stackElements[idx - 2].changeset, ex.changeset, pool);
+          this.stackElements.splice(idx - 2, 1);
+          idx--;
+        }
+      } else {
+        idx--;
+      }
+    }
+  }
+
+  getNthFromTop = (n: number) => {
+    // precond: 0 <= n < numEvents()
+    this.exposeEvent(n);
+    return this.stackElements[this.stackElements.length - 1 - n];
+  }
+  numEvents = () => this.numUndoableEvents;
+  popEvent = () => {
+    // precond: numEvents() > 0
+    this.exposeEvent(0);
+    this.numUndoableEvents--;
+    return this.stackElements.pop();
+  }
+}
+
+class UndoModule {
+  // invariant: stack always has at least one undoable event
+  private undoPtr = 0
+  private stack: Stack
+  public enabled: boolean
+  private readonly apool: AttributePool|null
+  constructor() {
+    this.stack = new Stack()
+    this.enabled =  true
+    this.apool =  null
+  }
+
+  clearHistory = () => {
+    this.stack.clearStack();
+    this.undoPtr = 0;
+  }
+
+  private charOccurrences = (str: string, c: string) => {
+    let i = 0;
+    let count = 0;
+    while (i >= 0 && i < str.length) {
+      i = str.indexOf(c, i);
+      if (i >= 0) {
+        count++;
+        i++;
+      }
+    }
+    return count;
+  }
+  private opcodeOccurrences = (cs: string, opcode: string) => this.charOccurrences(Changeset.unpack(cs).ops, opcode)
+  private mergeChangesets = (cs1: string, cs2:string) => {
+    if (!cs1) return cs2;
+    if (!cs2) return cs1;
+
+    // Rough heuristic for whether changesets should be considered one action:
+    // each does exactly one insertion, no dels, and the composition does also; or
+    // each does exactly one deletion, no ins, and the composition does also.
+    // A little weird in that it won't merge "make bold" with "insert char"
+    // but will merge "make bold and insert char" with "insert char",
+    // though that isn't expected to come up.
+    const plusCount1 = this.opcodeOccurrences(cs1, '+');
+    const plusCount2 = this.opcodeOccurrences(cs2, '+');
+    const minusCount1 = this.opcodeOccurrences(cs1, '-');
+    const minusCount2 = this.opcodeOccurrences(cs2, '-');
+    if (plusCount1 === 1 && plusCount2 === 1 && minusCount1 === 0 && minusCount2 === 0) {
+      const merge = Changeset.compose(cs1, cs2, this.getAPool());
+      const plusCount3 = this.opcodeOccurrences(merge, '+');
+      const minusCount3 = this.opcodeOccurrences(merge, '-');
+      if (plusCount3 === 1 && minusCount3 === 0) {
+        return merge;
+      }
+    } else if (plusCount1 === 0 && plusCount2 === 0 && minusCount1 === 1 && minusCount2 === 1) {
+      const merge = Changeset.compose(cs1, cs2, this.getAPool());
+      const plusCount3 = this.opcodeOccurrences(merge, '+');
+      const minusCount3 = this.opcodeOccurrences(merge, '-');
+      if (plusCount3 === 0 && minusCount3 === 1) {
+        return merge;
+      }
+    }
+    return null;
+  }
+
+  reportEvent = (event: any) => {
+    const topEvent = this.stack.getNthFromTop(0);
+
+    const applySelectionToTop = () => {
+      if ((typeof event.selStart) === 'number') {
+        topEvent.selStart = event.selStart;
+        topEvent.selEnd = event.selEnd;
+        topEvent.selFocusAtStart = event.selFocusAtStart;
+      }
+    };
+
+    if ((!event.backset) || Changeset.isIdentity(event.backset)) {
+      applySelectionToTop();
+    } else {
+      let merged = false;
+      if (topEvent.eventType === event.eventType) {
+        const merge = this.mergeChangesets(event.backset, topEvent.backset);
+        if (merge) {
+          topEvent.backset = merge;
+          applySelectionToTop();
+          merged = true;
+        }
+      }
+      if (!merged) {
+        /*
+         * Push the event on the undo stack only if it exists, and if it's
+         * not a "clearauthorship". This disallows undoing the removal of the
+         * authorship colors, but is a necessary stopgap measure against
+         * https://github.com/ether/etherpad-lite/issues/2802
+         */
+        if (event && (event.eventType !== 'clearauthorship')) {
+          this.stack.pushEvent(event);
+        }
+      }
+      this.undoPtr = 0;
+    }
+  }
+  reportExternalChange = (changeset: string) => {
+    if (changeset && !Changeset.isIdentity(changeset)) {
+      this.stack.pushExternalChange(changeset);
+    }
+  }
+  getSelectionInfo = (event: any) => {
+    if ((typeof event.selStart) !== 'number') {
+      return null;
+    } else {
+      return {
+        selStart: event.selStart,
+        selEnd: event.selEnd,
+        selFocusAtStart: event.selFocusAtStart,
+      };
+    }
+  }
+  // For "undo" and "redo", the change event must be returned
+  // by eventFunc and NOT reported through the normal mechanism.
+  // "eventFunc" should take a changeset and an optional selection info object,
+  // or can be called with no arguments to mean that no undo is possible.
+  // "eventFunc" will be called exactly once.
+
+  performUndo = (eventFunc: Function) => {
+    if (this.undoPtr < this.stack.numEvents() - 1) {
+      const backsetEvent = this.stack.getNthFromTop(this.undoPtr);
+      const selectionEvent = this.stack.getNthFromTop(this.undoPtr + 1);
+      const undoEvent = eventFunc(backsetEvent.backset, this.getSelectionInfo(selectionEvent));
+      this.stack.pushEvent(undoEvent);
+      this.undoPtr += 2;
+    } else { eventFunc(); }
+  }
+  performRedo = (eventFunc: Function) => {
+    if (this.undoPtr >= 2) {
+      const backsetEvent = this.stack.getNthFromTop(0);
+      const selectionEvent = this.stack.getNthFromTop(1);
+      eventFunc(backsetEvent.backset, this.getSelectionInfo(selectionEvent));
+      this.stack.popEvent();
+      this.undoPtr -= 2;
+    } else { eventFunc(); }
+  }
+  getAPool = () => this.apool;
+
+}
+
+export const undoModule = new UndoModule()
+