cray/epub/errors.js

Epub parser

/**
 * @author: Akshay Kr Singh.
 * @date:   20/11/15.
 * @github: https://github.com/akshayKrSingh
 */
// Require our core node modules.
var util = require( "util" );

/*// Export the constructor function.
exports.EpubError = EpubError;

// Export the factory function for the custom error object. The factory function lets
// the calling context create new EpubError instances without calling the [new] keyword.
exports.createEpubError = createEpubError;*/


// ----------------------------------------------------------------------------------- //
// ----------------------------------------------------------------------------------- //


// I create the new instance of the EpubError object, ensuring that it properly
// extends from the Error class.
function createEpubError( settings ) {

  // NOTE: We are overriding the "implementationContext" so that the createEpubError()
  // function is not part of the resulting stacktrace.
  return( new EpubError( settings, createEpubError ) );

}


// I am the custom error object for the application. The settings is a hash of optional
// properties for the error instance:
// --
// * type: I am the type of error being thrown.
// * message: I am the reason the error is being thrown.
// * detail: I am an explanation of the error.
// * extendedInfo: I am additional information about the error context.
// * errorCode: I am a custom error code associated with this type of error.
// --
// The implementationContext argument is an optional argument that can be used to trim
// the generated stacktrace. If not provided, it defaults to EpubError.
function EpubError( settings, implementationContext ) {

  // Ensure that settings exists to prevent reference errors.
  settings = ( settings || {} );

  // Override the default name property (Error). This is basically zero value-add.
  this.name = "EpubError";

  // Since I am used to ColdFusion, I am modeling the custom error structure on the
  // CFThrow functionality. Each of the following properties can be optionally passed-in
  // as part of the Settings argument.
  // --
  // See CFThrow documentation: https://wikidocs.adobe.com/wiki/display/coldfusionen/cfthrow
  this.type = ( settings.type || "Default" );
  this.message = ( settings.message || "An error occurred." );
  this.detail = ( settings.detail || "" );
  this.extendedInfo = ( settings.extendedInfo || "" );
  this.errorCode = ( settings.errorCode || "" );

  // This is just a flag that will indicate if the error is a custom EpubError. If this
  // is not an EpubError, this property will be undefined, which is a Falsely.
  this.isEpubError = true;

  // Capture the current stacktrace and store it in the property "this.stack". By
  // providing the implementationContext argument, we will remove the current
  // constructor (or the optional factory function) line-item from the stacktrace; this
  // is good because it will reduce the implementation noise in the stack property.
  // --
  // Read More: https://code.google.com/p/v8-wiki/wiki/JavaScriptStackTraceApi#Stack_trace_collection_for_custom_exceptions
  Error.captureStackTrace( this, ( implementationContext || EpubError ) );

}

util.inherits( EpubError, Error );

module.exports = {
  "EPUB#container": {
    "missing": createEpubError({
      type: "EPUB.MissingContainer",
      message: "Container XML file is missing!",
      errorCode: 404
    }),
    "format": createEpubError({
      type: "EPUB.InvalidContainer",
      "message": "Invalid Container XML file format"
    })
  },
  "EPUB#opf": {
    "missing": createEpubError({
      type: "EPUB.MissingOpf",
      message: "Opf file is missing!",
      code: 404
    }),
    "spine": createEpubError({
      type: "EPUB.InvalidSpine",
      message: "Spine entry not found in Manifest TAG"
    }),
    "format": createEpubError({
      type: "EPUB.InvalidOpf",
      message: "Invalid opf file format"
    })
  },
  "EPUB#spine": {
    "missing": createEpubError({
      type: "EPUB.MissingSpine",
      message: "Opf file is missing!",
      code: 404
    }),
    "spine": createEpubError({
      type: "EPUB.InvalidSpine",
      message: "Spine entry not found in Manifest TAG"
    })
  }
};