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var through = require('through2');
var speedometer = require('speedometer');
module.exports = function(options, onprogress) {
if (typeof options === 'function') return module.exports(null, options);
options = options || {};
var length = options.length || 0;
var time = options.time || 0;
var drain = options.drain || false;
var transferred = options.transferred || 0;
var nextUpdate = Date.now()+time;
var delta = 0;
var speed = speedometer(options.speed || 5000);
var startTime = Date.now();
var update = {
percentage: 0,
transferred: transferred,
length: length,
remaining: length,
eta: 0,
runtime: 0
};
var emit = function(ended) {
update.delta = delta;
update.percentage = ended ? 100 : (length ? transferred/length*100 : 0);
update.speed = speed(delta);
update.eta = Math.round(update.remaining / update.speed);
update.runtime = parseInt((Date.now() - startTime)/1000);
nextUpdate = Date.now()+time;
delta = 0;
tr.emit('progress', update);
};
var write = function(chunk, enc, callback) {
var len = options.objectMode ? 1 : chunk.length;
transferred += len;
delta += len;
update.transferred = transferred;
update.remaining = length >= transferred ? length - transferred : 0;
if (Date.now() >= nextUpdate) emit(false);
callback(null, chunk);
};
var end = function(callback) {
emit(true);
callback();
};
var tr = through(options.objectMode ? {objectMode:true, highWaterMark:16} : {}, write, end);
var onlength = function(newLength) {
length = newLength;
update.length = length;
update.remaining = length - update.transferred;
tr.emit('length', length);
};
// Expose `onlength()` handler as `setLength()` to support custom use cases where length
// is not known until after a few chunks have already been pumped, or is
// calculated on the fly.
tr.setLength = onlength;
tr.on('pipe', function(stream) {
if (typeof length === 'number') return;
// Support http module
if (stream.readable && !stream.writable && stream.headers) {
return onlength(parseInt(stream.headers['content-length'] || 0));
}
// Support streams with a length property
if (typeof stream.length === 'number') {
return onlength(stream.length);
}
// Support request module
stream.on('response', function(res) {
if (!res || !res.headers) return;
if (res.headers['content-encoding'] === 'gzip') return;
if (res.headers['content-length']) {
return onlength(parseInt(res.headers['content-length']));
}
});
});
if (drain) tr.resume();
if (onprogress) tr.on('progress', onprogress);
tr.progress = function() {
update.speed = speed(0);
update.eta = Math.round(update.remaining / update.speed);
return update;
};
return tr;
};
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