decaffeinate: Rename CommandRunner.coffee and 25 other files from .coffee to .js

app/coffee/OutputFileOptimiser.js

@@ -0,0 +1,55 @@
+fs = require "fs"
+Path = require "path"
+spawn = require("child_process").spawn
+logger = require "logger-sharelatex"
+Metrics = require "./Metrics"
+_ = require "underscore"
+
+module.exports = OutputFileOptimiser =
+
+	optimiseFile: (src, dst, callback = (error) ->) ->
+		# check output file (src) and see if we can optimise it, storing
+		# the result in the build directory (dst)
+		if src.match(/\/output\.pdf$/)
+			OutputFileOptimiser.checkIfPDFIsOptimised src, (err, isOptimised) ->
+				return callback(null) if err? or isOptimised
+				OutputFileOptimiser.optimisePDF src, dst, callback
+		else
+			callback (null)
+
+	checkIfPDFIsOptimised: (file, callback) ->
+		SIZE = 16*1024 # check the header of the pdf
+		result = new Buffer(SIZE)
+		result.fill(0) # prevent leakage of uninitialised buffer
+		fs.open file, "r", (err, fd) ->
+			return callback(err) if err?
+			fs.read fd, result, 0, SIZE, 0, (errRead, bytesRead, buffer) ->
+				fs.close fd, (errClose) ->
+					return callback(errRead) if errRead?
+					return callback(errClose) if errReadClose?
+					isOptimised = buffer.toString('ascii').indexOf("/Linearized 1") >= 0
+					callback(null, isOptimised)
+
+	optimisePDF: (src, dst, callback = (error) ->) ->
+		tmpOutput = dst + '.opt'
+		args = ["--linearize", src, tmpOutput]
+		logger.log args: args, "running qpdf command"
+
+		timer = new Metrics.Timer("qpdf")
+		proc = spawn("qpdf", args)
+		stdout = ""
+		proc.stdout.on "data", (chunk) ->
+			stdout += chunk.toString()
+		callback = _.once(callback) # avoid double call back for error and close event
+		proc.on "error", (err) ->
+			logger.warn {err, args}, "qpdf failed"
+			callback(null) # ignore the error
+		proc.on "close", (code) ->
+			timer.done()
+			if code != 0
+				logger.warn {code, args}, "qpdf returned error"
+				return callback(null) # ignore the error
+			fs.rename tmpOutput, dst, (err) ->
+				if err?
+					logger.warn {tmpOutput, dst}, "failed to rename output of qpdf command"
+				callback(null) # ignore the error