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joplin/ReactNativeClient/lib/models/Revision.js
2019-09-19 22:51:18 +01:00

259 lines
8.3 KiB
JavaScript

const BaseModel = require('lib/BaseModel.js');
const BaseItem = require('lib/models/BaseItem.js');
const DiffMatchPatch = require('diff-match-patch');
const ArrayUtils = require('lib/ArrayUtils.js');
const JoplinError = require('lib/JoplinError');
const { sprintf } = require('sprintf-js');
const dmp = new DiffMatchPatch();
class Revision extends BaseItem {
static tableName() {
return 'revisions';
}
static modelType() {
return BaseModel.TYPE_REVISION;
}
static createTextPatch(oldText, newText) {
return dmp.patch_toText(dmp.patch_make(oldText, newText));
}
static applyTextPatch(text, patch) {
patch = dmp.patch_fromText(patch);
const result = dmp.patch_apply(patch, text);
if (!result || !result.length) throw new Error('Could not apply patch');
return result[0];
}
static createObjectPatch(oldObject, newObject) {
if (!oldObject) oldObject = {};
const output = {
new: {},
deleted: [],
};
for (let k in newObject) {
if (!newObject.hasOwnProperty(k)) continue;
if (oldObject[k] === newObject[k]) continue;
output.new[k] = newObject[k];
}
for (let k in oldObject) {
if (!oldObject.hasOwnProperty(k)) continue;
if (!(k in newObject)) output.deleted.push(k);
}
return JSON.stringify(output);
}
static applyObjectPatch(object, patch) {
patch = JSON.parse(patch);
const output = Object.assign({}, object);
for (let k in patch.new) {
output[k] = patch.new[k];
}
for (let i = 0; i < patch.deleted.length; i++) {
delete output[patch.deleted[i]];
}
return output;
}
static patchStats(patch) {
if (typeof patch === 'object') throw new Error('Not implemented');
const countChars = diffLine => {
return unescape(diffLine).length - 1;
};
const lines = patch.split('\n');
let added = 0;
let removed = 0;
for (const line of lines) {
if (line.indexOf('-') === 0) {
removed += countChars(line);
continue;
}
if (line.indexOf('+') === 0) {
added += countChars(line);
continue;
}
}
return {
added: added,
removed: removed,
};
}
static revisionPatchStatsText(rev) {
const titleStats = this.patchStats(rev.title_diff);
const bodyStats = this.patchStats(rev.body_diff);
const total = {
added: titleStats.added + bodyStats.added,
removed: titleStats.removed + bodyStats.removed,
};
const output = [];
if (total.removed) output.push(`-${total.removed}`);
output.push(`+${total.added}`);
return output.join(', ');
}
static async countRevisions(itemType, itemId) {
const r = await this.db().selectOne('SELECT count(*) as total FROM revisions WHERE item_type = ? AND item_id = ?', [itemType, itemId]);
return r ? r.total : 0;
}
static latestRevision(itemType, itemId) {
return this.modelSelectOne('SELECT * FROM revisions WHERE item_type = ? AND item_id = ? ORDER BY item_updated_time DESC LIMIT 1', [itemType, itemId]);
}
static allByType(itemType, itemId) {
return this.modelSelectAll('SELECT * FROM revisions WHERE item_type = ? AND item_id = ? ORDER BY item_updated_time ASC', [itemType, itemId]);
}
static async itemsWithRevisions(itemType, itemIds) {
if (!itemIds.length) return [];
const rows = await this.db().selectAll(`SELECT distinct item_id FROM revisions WHERE item_type = ? AND item_id IN ("${itemIds.join('","')}")`, [itemType]);
return rows.map(r => r.item_id);
}
static async itemsWithNoRevisions(itemType, itemIds) {
const withRevs = await this.itemsWithRevisions(itemType, itemIds);
const output = [];
for (let i = 0; i < itemIds.length; i++) {
if (withRevs.indexOf(itemIds[i]) < 0) output.push(itemIds[i]);
}
return ArrayUtils.unique(output);
}
static moveRevisionToTop(revision, revs) {
let targetIndex = -1;
for (let i = revs.length - 1; i >= 0; i--) {
const rev = revs[i];
if (rev.id === revision.id) {
targetIndex = i;
break;
}
}
if (targetIndex < 0) throw new Error(`Could not find revision: ${revision.id}`);
if (targetIndex !== revs.length - 1) {
revs = revs.slice();
const toTop = revs[targetIndex];
revs.splice(targetIndex, 1);
revs.push(toTop);
}
return revs;
}
// Note: revs must be sorted by update_time ASC (as returned by allByType)
static async mergeDiffs(revision, revs = null) {
if (!('encryption_applied' in revision) || !!revision.encryption_applied) throw new JoplinError('Target revision is encrypted', 'revision_encrypted');
if (!revs) {
revs = await this.modelSelectAll('SELECT * FROM revisions WHERE item_type = ? AND item_id = ? AND item_updated_time <= ? ORDER BY item_updated_time ASC', [revision.item_type, revision.item_id, revision.item_updated_time]);
} else {
revs = revs.slice();
}
// Handle rare case where two revisions have been created at exactly the same millisecond
// Also handle even rarer case where a rev and its parent have been created at the
// same milliseconds. All code below expects target revision to be on top.
revs = this.moveRevisionToTop(revision, revs);
const output = {
title: '',
body: '',
metadata: {},
};
// Build up the list of revisions that are parents of the target revision.
const revIndexes = [revs.length - 1];
let parentId = revision.parent_id;
for (let i = revs.length - 2; i >= 0; i--) {
const rev = revs[i];
if (rev.id !== parentId) continue;
parentId = rev.parent_id;
revIndexes.push(i);
}
revIndexes.reverse();
for (const revIndex of revIndexes) {
const rev = revs[revIndex];
if (rev.encryption_applied) throw new JoplinError(sprintf('Revision "%s" is encrypted', rev.id), 'revision_encrypted');
output.title = this.applyTextPatch(output.title, rev.title_diff);
output.body = this.applyTextPatch(output.body, rev.body_diff);
output.metadata = this.applyObjectPatch(output.metadata, rev.metadata_diff);
}
return output;
}
static async deleteOldRevisions(ttl) {
// When deleting old revisions, we need to make sure that the oldest surviving revision
// is a "merged" one (as opposed to a diff from a now deleted revision). So every time
// we deleted a revision, we need to find if there's a corresponding surviving revision
// and modify that revision into a "merged" one.
const cutOffDate = Date.now() - ttl;
const revisions = await this.modelSelectAll('SELECT * FROM revisions WHERE item_updated_time < ? ORDER BY item_updated_time DESC', [cutOffDate]);
const doneItems = {};
for (const rev of revisions) {
const doneKey = `${rev.item_type}_${rev.item_id}`;
if (doneItems[doneKey]) continue;
const keptRev = await this.modelSelectOne('SELECT * FROM revisions WHERE item_updated_time >= ? AND item_type = ? AND item_id = ? ORDER BY item_updated_time ASC LIMIT 1', [cutOffDate, rev.item_type, rev.item_id]);
try {
const deleteQueryCondition = 'item_updated_time < ? AND item_id = ?';
const deleteQueryParams = [cutOffDate, rev.item_id];
const deleteQuery = { sql: `DELETE FROM revisions WHERE ${deleteQueryCondition}`, params: deleteQueryParams };
if (!keptRev) {
const hasEncrypted = await this.modelSelectOne(`SELECT * FROM revisions WHERE encryption_applied = 1 AND ${deleteQueryCondition}`, deleteQueryParams);
if (hasEncrypted) throw new JoplinError('One of the revision to be deleted is encrypted', 'revision_encrypted');
await this.db().transactionExecBatch([deleteQuery]);
} else {
// Note: we don't need to check for encrypted rev here because
// mergeDiff will already throw the revision_encrypted exception
// if a rev is encrypted.
const merged = await this.mergeDiffs(keptRev);
const queries = [deleteQuery, { sql: 'UPDATE revisions SET title_diff = ?, body_diff = ?, metadata_diff = ? WHERE id = ?', params: [this.createTextPatch('', merged.title), this.createTextPatch('', merged.body), this.createObjectPatch({}, merged.metadata), keptRev.id] }];
await this.db().transactionExecBatch(queries);
}
} catch (error) {
if (error.code === 'revision_encrypted') {
this.logger().info(`Aborted deletion of old revisions for item ${rev.item_id} because one of the revisions is still encrypted`, error);
} else {
throw error;
}
}
doneItems[doneKey] = true;
}
}
static async revisionExists(itemType, itemId, updatedTime) {
const existingRev = await Revision.latestRevision(itemType, itemId);
return existingRev && existingRev.item_updated_time === updatedTime;
}
}
module.exports = Revision;