forked from zhurui/management
128 lines
2.9 KiB
JavaScript
128 lines
2.9 KiB
JavaScript
var hpack = require('../hpack');
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var utils = hpack.utils;
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var encoder = hpack.encoder;
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var table = hpack.table;
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var assert = utils.assert;
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var inherits = require('inherits');
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var Duplex = require('readable-stream').Duplex;
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function Compressor(options) {
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Duplex.call(this, {
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writableObjectMode: true
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});
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this._encoder = null;
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this._table = table.create(options.table);
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}
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inherits(Compressor, Duplex);
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module.exports = Compressor;
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Compressor.create = function create(options) {
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return new Compressor(options);
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};
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Compressor.prototype._read = function _read() {
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// We only push!
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};
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Compressor.prototype._write = function _write(data, enc, cb) {
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assert(Array.isArray(data), 'Compressor.write() expects list of headers');
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this._encoder = encoder.create();
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for (var i = 0; i < data.length; i++)
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this._encodeHeader(data[i]);
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var data = this._encoder.render();
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this._encoder = null;
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cb(null);
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for (var i = 0; i < data.length; i++)
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this.push(data[i]);
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};
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Compressor.prototype.updateTableSize = function updateTableSize(size) {
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if (size >= this._table.protocolMaxSize) {
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size = this._table.protocolMaxSize;
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var enc = encoder.create();
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// indexed = 0
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// incremental = 0
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// update = 1
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enc.encodeBits(1, 3);
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enc.encodeInt(size);
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var data = enc.render();
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for (var i = 0; i < data.length; i++)
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this.push(data[i]);
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}
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this._table.updateSize(size);
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};
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Compressor.prototype.reset = function reset() {
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var enc = encoder.create();
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var size = this._table.maxSize;
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// indexed = 0
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// incremental = 0
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// update = 1
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enc.encodeBits(1, 3);
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enc.encodeInt(0);
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// Evict everything
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this._table.updateSize(0);
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// indexed = 0
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// incremental = 0
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// update = 1
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enc.encodeBits(1, 3);
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enc.encodeInt(size);
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// Revert size
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this._table.updateSize(size);
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var data = enc.render();
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for (var i = 0; i < data.length; i++)
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this.push(data[i]);
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};
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Compressor.prototype._encodeHeader = function _encodeHeader(header) {
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if (header.neverIndex) {
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var index = 0;
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var neverIndex = 1;
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var isIndexed = 0;
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var isIncremental = 0;
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} else {
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var index = this._table.reverseLookup(header.name, header.value);
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var isIndexed = index > 0;
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var isIncremental = header.incremental !== false;
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var neverIndex = 0;
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}
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this._encoder.encodeBit(isIndexed);
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if (isIndexed) {
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this._encoder.encodeInt(index);
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return;
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}
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var name = utils.toArray(header.name);
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var value = utils.toArray(header.value);
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this._encoder.encodeBit(isIncremental);
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if (isIncremental) {
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this._table.add(header.name, header.value, name.length, value.length);
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} else {
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// Update = false
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this._encoder.encodeBit(0);
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this._encoder.encodeBit(neverIndex);
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}
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// index is negative for `name`-only headers
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this._encoder.encodeInt(-index);
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if (index === 0)
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this._encoder.encodeStr(name, header.huffman !== false);
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this._encoder.encodeStr(value, header.huffman !== false);
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};
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