backtrace-morgue/lib/crdb.js

command line interface to the Backtrace object store

"use strict";

class Response {
  /**
   * This instantiates a coroner object associated with the specified
   * end-point.
   */
  constructor(json) {
    if (json.error)
      this.json = {};

    this.json = json;
  }

  get count() {
    return this.json.objects.length;
  }

  unpackObject() {
    var i;
    var json = this.json;
    var result = {};

    /*
     * The first step is to construct object arrays. This is a sequence of
     * arrays whose first element is group identifier.
     */
    for (i = 0; i < json.objects.length; i++) {
      var object = json.objects[i];
      var label = object[0];
      var rle = object[1];
      var target;
      var order = [];
      var j;

      if (result[label] === undefined) {
        target = result[label] = [];
      }

      /*
       * We expect a sequence of tuples consisting of a base and then sequence
       * length.
       */
      for (j = 0; j < rle.length; j++) {
        target.push({'object' : rle[j][0], 'id' : rle[j][0].toString(16) });

        if (rle[j].length === 2) {
          var k;

          /*
           * If run-length is provided, then materialize those objects.
           */
          for (k = 1; k <= rle[j][1]; k++)
            target.push({
                'object' : rle[j][0] + k,
                'id' : (rle[j][0] + k).toString(16)
            });
        }
      }
    }

    /*
     * At this point, the full object table has been constructed. Now we walk
     * through the values array. Values are also RLE-encoded by default,
     * and are attributed in object order.
     */
    for (i = 0; i < json.values.length; i = i + json.columns.length) {
      var j;

      for (j = 0; j < json.columns.length; j++) {
        var label = json.columns[j % json.columns.length][0];
        var key = json.values[i + j][0];
        var values = json.values[i + j];
        var counter = 0;
        var k;

        if (result[key] === undefined) {
          console.log('Unknown key: ' + key);
          continue;
        }

        for (k = 1; k < values.length; k++) {
          var base = values[k][0];
          var r;

          for (r = 0; r < values[k][1]; r++) {
            result[key][counter][label] = base;
            counter++;
          }
        }
      }
    }

    return result;
  }

  fields() {
    var i;

    if (this._fields)
      return this._fields;

    this._fields = {};

    for (i = 0; i < this.json.columns.length; i++)
      this._fields[this.json.columns[i][0]] = this.json.columns[i][1];

    return this._fields;
  }

  /**
   * If object projection is occurring then cache per-column RLE
   * state.
   */
  unpack() {
    var result = {};
    var i, cursor;

    /*
     * If the objects array exists then object materialization is requested.
     */
    if (this.json.objects)
      return this.unpackObject();

    /* Now we extract every column value. */
    for (i = 0; i < this.json.values.length; i++) {
      var field = this.json.values[i];
      var factor = field[0];
      var j;
      var count = null;

      if (field.length > 2) {
        count = field[2];
      }

      if (result[factor] === undefined) {
        result[factor] = {};
        if (count)
          result[factor].count = count;
      }

      for (j = 0; j < this.json.columns.length; j++) {
        var label = this.json.columns[j][0];
        result[factor][label] = field[1][j];
      }
    }

    return result;
  }

  row(id) {
    var length = this.json.columns.length;
    var row = this.json.values[id];
    var result = {};
    var i;

    for (i = 0; i < length; i++) {
      var label = this.json.columns[i];

      if (this.json.columns[i].startsWith('unique(') === true) {
              result[label] = row[1][i][0];
      } else {
              result[label] = row[1][i];
      }
    }

    return [row[0], result];
  }
}

module.exports.Response = Response;

//-- vim:ts=2:et:sw=2