overleaf/services/track-changes/app/js/DiffManager.js

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/* eslint-disable
camelcase,
handle-callback-err,
*/
// TODO: This file was created by bulk-decaffeinate.
// Fix any style issues and re-enable lint.
/*
* decaffeinate suggestions:
* DS101: Remove unnecessary use of Array.from
* DS102: Remove unnecessary code created because of implicit returns
* DS207: Consider shorter variations of null checks
* Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
*/
let DiffManager
const UpdatesManager = require('./UpdatesManager')
const DocumentUpdaterManager = require('./DocumentUpdaterManager')
const DiffGenerator = require('./DiffGenerator')
const logger = require('logger-sharelatex')
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module.exports = DiffManager = {
getLatestDocAndUpdates(project_id, doc_id, fromVersion, callback) {
// Get updates last, since then they must be ahead and it
// might be possible to rewind to the same version as the doc.
if (callback == null) {
callback = function(error, content, version, updates) {}
}
return DocumentUpdaterManager.getDocument(project_id, doc_id, function(
error,
content,
version
) {
if (error != null) {
return callback(error)
}
if (fromVersion == null) {
// If we haven't been given a version, just return lastest doc and no updates
return callback(null, content, version, [])
}
return UpdatesManager.getDocUpdatesWithUserInfo(
project_id,
doc_id,
{ from: fromVersion },
function(error, updates) {
if (error != null) {
return callback(error)
}
return callback(null, content, version, updates)
}
)
})
},
getDiff(project_id, doc_id, fromVersion, toVersion, callback) {
if (callback == null) {
callback = function(error, diff) {}
}
return DiffManager.getDocumentBeforeVersion(
project_id,
doc_id,
fromVersion,
function(error, startingContent, updates) {
let diff
if (error != null) {
if (error.message === 'broken-history') {
return callback(null, 'history unavailable')
} else {
return callback(error)
}
}
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const updatesToApply = []
for (const update of Array.from(updates.slice().reverse())) {
if (update.v <= toVersion) {
updatesToApply.push(update)
}
}
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try {
diff = DiffGenerator.buildDiff(startingContent, updatesToApply)
} catch (e) {
return callback(e)
}
return callback(null, diff)
}
)
},
getDocumentBeforeVersion(project_id, doc_id, version, _callback) {
// Whichever order we get the latest document and the latest updates,
// there is potential for updates to be applied between them so that
// they do not return the same 'latest' versions.
// If this happens, we just retry and hopefully get them at the compatible
// versions.
let retry
if (_callback == null) {
_callback = function(error, document, rewoundUpdates) {}
}
let retries = 3
const callback = function(error, ...args) {
if (error != null) {
if (error.retry && retries > 0) {
logger.warn(
{ error, project_id, doc_id, version, retries },
'retrying getDocumentBeforeVersion'
)
return retry()
} else {
return _callback(error)
}
} else {
return _callback(null, ...Array.from(args))
}
}
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return (retry = function() {
retries--
return DiffManager._tryGetDocumentBeforeVersion(
project_id,
doc_id,
version,
callback
)
})()
},
_tryGetDocumentBeforeVersion(project_id, doc_id, version, callback) {
if (callback == null) {
callback = function(error, document, rewoundUpdates) {}
}
logger.log(
{ project_id, doc_id, version },
'getting document before version'
)
return DiffManager.getLatestDocAndUpdates(
project_id,
doc_id,
version,
function(error, content, version, updates) {
let startingContent
if (error != null) {
return callback(error)
}
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// bail out if we hit a broken update
for (const u of Array.from(updates)) {
if (u.broken) {
return callback(new Error('broken-history'))
}
}
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// discard any updates which are ahead of this document version
while ((updates[0] != null ? updates[0].v : undefined) >= version) {
updates.shift()
}
const lastUpdate = updates[0]
if (lastUpdate != null && lastUpdate.v !== version - 1) {
error = new Error(
`latest update version, ${lastUpdate.v}, does not match doc version, ${version}`
)
error.retry = true
return callback(error)
}
logger.log(
{
docVersion: version,
lastUpdateVersion: lastUpdate != null ? lastUpdate.v : undefined,
updateCount: updates.length
},
'rewinding updates'
)
const tryUpdates = updates.slice().reverse()
try {
startingContent = DiffGenerator.rewindUpdates(content, tryUpdates)
// tryUpdates is reversed, and any unapplied ops are marked as broken
} catch (e) {
return callback(e)
}
return callback(null, startingContent, tryUpdates)
}
)
}
}