Code coverage report for chunkstream.js

# All files chunkstream.js

90.11% Statements 82/91
81.4% Branches 35/43
100% Functions 10/10
90.11% Lines 82/91

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     "use strict";

    let util = require("util");
    let Stream = require("stream");

    let ChunkStream = (module.exports = function () {
      Stream.call(this);

      this._buffers = [];
      this._buffered = 0;

      this._reads = [];
      this._paused = false;

      this._encoding = "utf8";
      this.writable = true;
    });
    util.inherits(ChunkStream, Stream);

    ChunkStream.prototype.read = function (length, callback) {
      this._reads.push({
        length: Math.abs(length), // if length < 0 then at most this length
        allowLess: length < 0,
        func: callback,
      });

      process.nextTick(
        function () {
          this._process();

          // its paused and there is not enought data then ask for more
          Iif (this._paused && this._reads.length > 0) {
            this._paused = false;

            this.emit("drain");
          }
        }.bind(this)
      );
    };

    ChunkStream.prototype.write = function (data, encoding) {
      Iif (!this.writable) {
        this.emit("error", new Error("Stream not writable"));
        return false;
      }

      let dataBuffer;
      Eif (Buffer.isBuffer(data)) {
        dataBuffer = data;
      } else {
        dataBuffer = Buffer.from(data, encoding || this._encoding);
      }

      this._buffers.push(dataBuffer);
      this._buffered += dataBuffer.length;

      this._process();

      // ok if there are no more read requests
      if (this._reads && this._reads.length === 0) {
        this._paused = true;
      }

      return this.writable && !this._paused;
    };

    ChunkStream.prototype.end = function (data, encoding) {
      Iif (data) {
        this.write(data, encoding);
      }

      this.writable = false;

      // already destroyed
      Iif (!this._buffers) {
        return;
      }

      // enqueue or handle end
      if (this._buffers.length === 0) {
        this._end();
      } else {
        this._buffers.push(null);
        this._process();
      }
    };

    ChunkStream.prototype.destroySoon = ChunkStream.prototype.end;

    ChunkStream.prototype._end = function () {
      if (this._reads.length > 0) {
        this.emit("error", new Error("Unexpected end of input"));
      }

      this.destroy();
    };

    ChunkStream.prototype.destroy = function () {
      Iif (!this._buffers) {
        return;
      }

      this.writable = false;
      this._reads = null;
      this._buffers = null;

      this.emit("close");
    };

    ChunkStream.prototype._processReadAllowingLess = function (read) {
      // ok there is any data so that we can satisfy this request
      this._reads.shift(); // == read

      // first we need to peek into first buffer
      let smallerBuf = this._buffers[0];

      // ok there is more data than we need
      if (smallerBuf.length > read.length) {
        this._buffered -= read.length;
        this._buffers[0] = smallerBuf.slice(read.length);

        read.func.call(this, smallerBuf.slice(0, read.length));
      } else {
        // ok this is less than maximum length so use it all
        this._buffered -= smallerBuf.length;
        this._buffers.shift(); // == smallerBuf

        read.func.call(this, smallerBuf);
      }
    };

    ChunkStream.prototype._processRead = function (read) {
      this._reads.shift(); // == read

      let pos = 0;
      let count = 0;
      let data = Buffer.alloc(read.length);

      // create buffer for all data
      while (pos < read.length) {
        let buf = this._buffers[count++];
        let len = Math.min(buf.length, read.length - pos);

        buf.copy(data, pos, 0, len);
        pos += len;

        // last buffer wasn't used all so just slice it and leave
        if (len !== buf.length) {
          this._buffers[--count] = buf.slice(len);
        }
      }

      // remove all used buffers
      if (count > 0) {
        this._buffers.splice(0, count);
      }

      this._buffered -= read.length;

      read.func.call(this, data);
    };

    ChunkStream.prototype._process = function () {
      try {
        // as long as there is any data and read requests
        while (this._buffered > 0 && this._reads && this._reads.length > 0) {
          let read = this._reads[0];

          // read any data (but no more than length)
          if (read.allowLess) {
            this._processReadAllowingLess(read);
          } else if (this._buffered >= read.length) {
            // ok we can meet some expectations

            this._processRead(read);
          } else {
            // not enought data to satisfy first request in queue
            // so we need to wait for more
            break;
          }
        }

        if (this._buffers && !this.writable) {
          this._end();
        }
      } catch (ex) {
        this.emit("error", ex);
      }
    };