overleaf/services/clsi/app/js/OutputFileOptimiser.js

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/* eslint-disable
no-return-assign,
no-undef,
no-unused-vars,
node/no-deprecated-api,
*/
// TODO: This file was created by bulk-decaffeinate.
// Fix any style issues and re-enable lint.
/*
* decaffeinate suggestions:
* 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 OutputFileOptimiser
const fs = require('fs')
const Path = require('path')
const { spawn } = require('child_process')
const logger = require('@overleaf/logger')
const Metrics = require('./Metrics')
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const _ = require('lodash')
module.exports = OutputFileOptimiser = {
optimiseFile(src, dst, callback) {
// check output file (src) and see if we can optimise it, storing
// the result in the build directory (dst)
if (callback == null) {
callback = function () {}
}
if (src.match(/\/output\.pdf$/)) {
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return OutputFileOptimiser.checkIfPDFIsOptimised(
src,
function (err, isOptimised) {
if (err != null || isOptimised) {
return callback(null)
}
return OutputFileOptimiser.optimisePDF(src, dst, callback)
}
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)
} else {
return callback(null)
}
},
checkIfPDFIsOptimised(file, callback) {
const SIZE = 16 * 1024 // check the header of the pdf
const result = Buffer.alloc(SIZE) // fills with zeroes by default
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return fs.open(file, 'r', function (err, fd) {
if (err != null) {
return callback(err)
}
return fs.read(fd, result, 0, SIZE, 0, (errRead, bytesRead, buffer) =>
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fs.close(fd, function (errClose) {
if (errRead != null) {
return callback(errRead)
}
if (typeof errReadClose !== 'undefined' && errReadClose !== null) {
return callback(errClose)
}
const isOptimised =
buffer.toString('ascii').indexOf('/Linearized 1') >= 0
return callback(null, isOptimised)
})
)
})
},
optimisePDF(src, dst, callback) {
if (callback == null) {
callback = function () {}
}
const tmpOutput = dst + '.opt'
const args = ['--linearize', '--newline-before-endstream', src, tmpOutput]
logger.log({ args }, 'running qpdf command')
const timer = new Metrics.Timer('qpdf')
const proc = spawn('qpdf', args)
let stdout = ''
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proc.stdout.setEncoding('utf8').on('data', chunk => (stdout += chunk))
callback = _.once(callback) // avoid double call back for error and close event
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proc.on('error', function (err) {
logger.warn({ err, args }, 'qpdf failed')
return callback(null)
}) // ignore the error
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return proc.on('close', function (code) {
timer.done()
if (code !== 0) {
logger.warn({ code, args }, 'qpdf returned error')
return callback(null) // ignore the error
}
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return fs.rename(tmpOutput, dst, function (err) {
if (err != null) {
logger.warn(
{ tmpOutput, dst },
'failed to rename output of qpdf command'
)
}
return callback(null)
})
})
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}, // ignore the error
}