src/messages.js

// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


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

const kVowelSounds = {a: true, e: true, i: true, o: true, u: true, y: true};
const kCapitalVowelSounds = {a: true, e: true, i: true, o: true, u: true,
    h: true, f: true, l: true, m: true, n: true, r: true, s: true, x: true,
    y: true};

function GetInstanceName(cons) {
  if (cons.length == 0) {
    return "";
  }
  var first = cons.charAt(0).toLowerCase();
  var mapping = kVowelSounds;
  if (cons.length > 1 && (cons.charAt(0) != first)) {
    // First char is upper case
    var second = cons.charAt(1).toLowerCase();
    // Second char is upper case
    if (cons.charAt(1) != second)
      mapping = kCapitalVowelSounds;
  }
  var s = mapping[first] ? "an " : "a ";
  return s + cons;
}


const kMessages = {
  // Error
  cyclic_proto:                 "Cyclic __proto__ value",
  // TypeError
  unexpected_token:             "Unexpected token %0",
  unexpected_token_number:      "Unexpected number",
  unexpected_token_string:      "Unexpected string",
  unexpected_token_identifier:  "Unexpected identifier",
  unexpected_eos:               "Unexpected end of input",
  expected_label:               "Expected label",
  malformed_regexp:             "Invalid regular expression: /%0/: %1",
  unterminated_regexp:          "Invalid regular expression: missing /",
  pcre_error:                   "PCRE function %0, error code %1",
  regexp_flags:                 "Cannot supply flags when constructing one RegExp from another",
  invalid_lhs_in_assignment:    "Invalid left-hand side in assignment",
  invalid_lhs_in_for_in:        "Invalid left-hand side in for-in",
  invalid_lhs_in_postfix_op:    "Invalid left-hand side expression in postfix operation",
  invalid_lhs_in_prefix_op:     "Invalid left-hand side expression in prefix operation",
  multiple_defaults_in_switch:  "More than one default clause in switch statement",
  newline_after_throw:          "Illegal newline after throw",
  redeclaration:                "%0 '%1' has already been declared",
  no_catch_or_finally:          "Missing catch or finally after try",
  unknown_label:                "Undefined label '%0'",
  invalid_break:                "Invalid break statement",
  invalid_continue:             "Invalid continue statement",
  uncaught_exception:           "Uncaught %0",
  stack_trace:                  "Stack Trace:\n%0",
  called_non_callable:          "%0 is not a function",
  undefined_method:             "Object %1 has no method '%0'",
  property_not_function:        "Property '%0' of object %1 is not a function",
  null_or_undefined:            "Cannot access property of null or undefined",
  cannot_convert_to_primitive:  "Cannot convert object to primitive value",
  not_constructor:              "%0 is not a constructor",
  not_defined:                  "%0 is not defined",
  non_object_property_load:     "Cannot read property '%0' of %1",
  non_object_property_store:    "Cannot set property '%0' of %1",
  non_object_property_call:     "Cannot call method '%0' of %1",
  illegal_eval:                 "Unsupported indirect eval() call",
  with_expression:              "%0 has no properties",
  illegal_invocation:           "Illegal invocation",
  no_setter_in_callback:        "Cannot set property %0 of %1 which has only a getter",
  apply_non_function:           "Function.prototype.apply was called on %0, which is a %1 and not a function",
  apply_wrong_args:             "Function.prototype.apply: Arguments list has wrong type",
  invalid_in_operator_use:      "Cannot use 'in' operator to search for '%0' in %1",
  instanceof_function_expected: "Expecting a function in instanceof check, but got %0",
  instanceof_nonobject_proto:   "Function has non-object prototype '%0' in instanceof check",
  null_to_object:               "Cannot convert null to object",
  reduce_no_initial:            "Reduce of empty array with no initial value",
  // RangeError
  invalid_array_length:         "Invalid array length",
  invalid_array_apply_length:   "Function.prototype.apply supports only up to 1024 arguments",
  stack_overflow:               "Maximum call stack size exceeded",
  apply_overflow:               "Function.prototype.apply cannot support %0 arguments",
  // SyntaxError
  unable_to_parse:              "Parse error",
  duplicate_regexp_flag:        "Duplicate RegExp flag %0",
  unrecognized_regexp_flag:     "Unrecognized RegExp flag %0",
  invalid_regexp:               "Invalid RegExp pattern /%0/",
  illegal_break:                "Illegal break statement",
  illegal_continue:             "Illegal continue statement",
  illegal_return:               "Illegal return statement",
  error_loading_debugger:       "Error loading debugger %0",
  no_input_to_regexp:           "No input to %0",
  result_not_primitive:         "Result of %0 must be a primitive, was %1",
  invalid_json:                 "String '%0' is not valid JSON",
  circular_structure:           "Converting circular structure to JSON"
};


function FormatString(format, args) {
  var result = format;
  for (var i = 0; i < args.length; i++) {
    var str;
    try { str = ToDetailString(args[i]); }
    catch (e) { str = "#<error>"; }
    result = result.split("%" + i).join(str);
  }
  return result;
}


function ToDetailString(obj) {
  if (obj != null && IS_OBJECT(obj) && obj.toString === $Object.prototype.toString) {
    var constructor = obj.constructor;
    if (!constructor) return ToString(obj);
    var constructorName = constructor.name;
    if (!constructorName) return ToString(obj);
    return "#<" + GetInstanceName(constructorName) + ">";
  } else {
    return ToString(obj);
  }
}


function MakeGenericError(constructor, type, args) {
  if (args instanceof $Array) {
    for (var i = 0; i < args.length; i++) {
      var elem = args[i];
      if (elem instanceof $Array && elem.length > 100) { // arbitrary limit, grab a reasonable slice to report
        args[i] = elem.slice(0,20).concat("...");
      }
    }
  } else if (IS_UNDEFINED(args)) {
    args = [];
  }

  var e = new constructor(kAddMessageAccessorsMarker);
  e.type = type;
  e.arguments = args;
  return e;
}


/**
 * Setup the Script function and constructor.
 */
%FunctionSetInstanceClassName(Script, 'Script');
%SetProperty(Script.prototype, 'constructor', Script, DONT_ENUM);
%SetCode(Script, function(x) {
  // Script objects can only be created by the VM.
  throw new $Error("Not supported");
});


// Helper functions; called from the runtime system.
function FormatMessage(message) {
  var format = kMessages[message.type];
  if (!format) return "<unknown message " + message.type + ">";
  return FormatString(format, message.args);
}


function GetLineNumber(message) {
  if (message.startPos == -1) return -1;
  var location = message.script.locationFromPosition(message.startPos, true);
  if (location == null) return -1;
  return location.line + 1;
}


// Returns the source code line containing the given source
// position, or the empty string if the position is invalid.
function GetSourceLine(message) {
  var location = message.script.locationFromPosition(message.startPos, true);
  if (location == null) return "";
  location.restrict();
  return location.sourceText();
}


function MakeTypeError(type, args) {
  return MakeGenericError($TypeError, type, args);
}


function MakeRangeError(type, args) {
  return MakeGenericError($RangeError, type, args);
}


function MakeSyntaxError(type, args) {
  return MakeGenericError($SyntaxError, type, args);
}


function MakeReferenceError(type, args) {
  return MakeGenericError($ReferenceError, type, args);
}


function MakeEvalError(type, args) {
  return MakeGenericError($EvalError, type, args);
}


function MakeError(type, args) {
  return MakeGenericError($Error, type, args);
}

/**
 * Find a line number given a specific source position.
 * @param {number} position The source position.
 * @return {number} 0 if input too small, -1 if input too large,
       else the line number.
 */
Script.prototype.lineFromPosition = function(position) {
  var lower = 0;
  var upper = this.lineCount() - 1;

  // We'll never find invalid positions so bail right away.
  if (position > this.line_ends[upper]) {
    return -1;
  }

  // This means we don't have to safe-guard indexing line_ends[i - 1].
  if (position <= this.line_ends[0]) {
    return 0;
  }

  // Binary search to find line # from position range.
  while (upper >= 1) {
    var i = (lower + upper) >> 1;

    if (position > this.line_ends[i]) {
      lower = i + 1;
    } else if (position <= this.line_ends[i - 1]) {
      upper = i - 1;
    } else {
      return i;
    }
  }
  return -1;
}

/**
 * Get information on a specific source position.
 * @param {number} position The source position
 * @param {boolean} include_resource_offset Set to true to have the resource
 *     offset added to the location
 * @return {SourceLocation}
 *     If line is negative or not in the source null is returned.
 */
Script.prototype.locationFromPosition = function (position,
                                                  include_resource_offset) {
  var line = this.lineFromPosition(position);
  if (line == -1) return null;

  // Determine start, end and column.
  var start = line == 0 ? 0 : this.line_ends[line - 1] + 1;
  var end = this.line_ends[line];
  if (end > 0 && this.source.charAt(end - 1) == '\r') end--;
  var column = position - start;

  // Adjust according to the offset within the resource.
  if (include_resource_offset) {
    line += this.line_offset;
    if (line == this.line_offset) {
      column += this.column_offset;
    }
  }

  return new SourceLocation(this, position, line, column, start, end);
};


/**
 * Get information on a specific source line and column possibly offset by a
 * fixed source position. This function is used to find a source position from
 * a line and column position. The fixed source position offset is typically
 * used to find a source position in a function based on a line and column in
 * the source for the function alone. The offset passed will then be the
 * start position of the source for the function within the full script source.
 * @param {number} opt_line The line within the source. Default value is 0
 * @param {number} opt_column The column in within the line. Default value is 0
 * @param {number} opt_offset_position The offset from the begining of the
 *     source from where the line and column calculation starts. Default value is 0
 * @return {SourceLocation}
 *     If line is negative or not in the source null is returned.
 */
Script.prototype.locationFromLine = function (opt_line, opt_column, opt_offset_position) {
  // Default is the first line in the script. Lines in the script is relative
  // to the offset within the resource.
  var line = 0;
  if (!IS_UNDEFINED(opt_line)) {
    line = opt_line - this.line_offset;
  }

  // Default is first column. If on the first line add the offset within the
  // resource.
  var column = opt_column || 0;
  if (line == 0) {
    column -= this.column_offset
  }

  var offset_position = opt_offset_position || 0;
  if (line < 0 || column < 0 || offset_position < 0) return null;
  if (line == 0) {
    return this.locationFromPosition(offset_position + column, false);
  } else {
    // Find the line where the offset position is located.
    var offset_line = this.lineFromPosition(offset_position);

    if (offset_line == -1 || offset_line + line >= this.lineCount()) {
      return null;
    }

    return this.locationFromPosition(this.line_ends[offset_line + line - 1] + 1 + column);  // line > 0 here.
  }
}


/**
 * Get a slice of source code from the script. The boundaries for the slice is
 * specified in lines.
 * @param {number} opt_from_line The first line (zero bound) in the slice.
 *     Default is 0
 * @param {number} opt_to_column The last line (zero bound) in the slice (non
 *     inclusive). Default is the number of lines in the script
 * @return {SourceSlice} The source slice or null of the parameters where
 *     invalid
 */
Script.prototype.sourceSlice = function (opt_from_line, opt_to_line) {
  var from_line = IS_UNDEFINED(opt_from_line) ? this.line_offset : opt_from_line;
  var to_line = IS_UNDEFINED(opt_to_line) ? this.line_offset + this.lineCount() : opt_to_line

  // Adjust according to the offset within the resource.
  from_line -= this.line_offset;
  to_line -= this.line_offset;
  if (from_line < 0) from_line = 0;
  if (to_line > this.lineCount()) to_line = this.lineCount();

  // Check parameters.
  if (from_line >= this.lineCount() ||
      to_line < 0 ||
      from_line > to_line) {
    return null;
  }

  var from_position = from_line == 0 ? 0 : this.line_ends[from_line - 1] + 1;
  var to_position = to_line == 0 ? 0 : this.line_ends[to_line - 1] + 1;

  // Return a source slice with line numbers re-adjusted to the resource.
  return new SourceSlice(this, from_line + this.line_offset, to_line + this.line_offset,
                         from_position, to_position);
}


Script.prototype.sourceLine = function (opt_line) {
  // Default is the first line in the script. Lines in the script are relative
  // to the offset within the resource.
  var line = 0;
  if (!IS_UNDEFINED(opt_line)) {
    line = opt_line - this.line_offset;
  }

  // Check parameter.
  if (line < 0 || this.lineCount() <= line) {
    return null;
  }

  // Return the source line.
  var start = line == 0 ? 0 : this.line_ends[line - 1] + 1;
  var end = this.line_ends[line];
  return this.source.substring(start, end);
}


/**
 * Returns the number of source lines.
 * @return {number}
 *     Number of source lines.
 */
Script.prototype.lineCount = function() {
  // Return number of source lines.
  return this.line_ends.length;
};


/**
 * Class for source location. A source location is a position within some
 * source with the following properties:
 *   script   : script object for the source
 *   line     : source line number
 *   column   : source column within the line
 *   position : position within the source
 *   start    : position of start of source context (inclusive)
 *   end      : position of end of source context (not inclusive)
 * Source text for the source context is the character interval [start, end[. In
 * most cases end will point to a newline character. It might point just past
 * the final position of the source if the last source line does not end with a
 * newline character.
 * @param {Script} script The Script object for which this is a location
 * @param {number} position Source position for the location
 * @param {number} line The line number for the location
 * @param {number} column The column within the line for the location
 * @param {number} start Source position for start of source context
 * @param {number} end Source position for end of source context
 * @constructor
 */
function SourceLocation(script, position, line, column, start, end) {
  this.script = script;
  this.position = position;
  this.line = line;
  this.column = column;
  this.start = start;
  this.end = end;
}


const kLineLengthLimit = 78;

/**
 * Restrict source location start and end positions to make the source slice
 * no more that a certain number of characters wide.
 * @param {number} opt_limit The with limit of the source text with a default
 *     of 78
 * @param {number} opt_before The number of characters to prefer before the
 *     position with a default value of 10 less that the limit
 */
SourceLocation.prototype.restrict = function (opt_limit, opt_before) {
  // Find the actual limit to use.
  var limit;
  var before;
  if (!IS_UNDEFINED(opt_limit)) {
    limit = opt_limit;
  } else {
    limit = kLineLengthLimit;
  }
  if (!IS_UNDEFINED(opt_before)) {
    before = opt_before;
  } else {
    // If no before is specified center for small limits and perfer more source
    // before the the position that after for longer limits.
    if (limit <= 20) {
      before = $floor(limit / 2);
    } else {
      before = limit - 10;
    }
  }
  if (before >= limit) {
    before = limit - 1;
  }

  // If the [start, end[ interval is too big we restrict
  // it in one or both ends. We make sure to always produce
  // restricted intervals of maximum allowed size.
  if (this.end - this.start > limit) {
    var start_limit = this.position - before;
    var end_limit = this.position + limit - before;
    if (this.start < start_limit && end_limit < this.end) {
      this.start = start_limit;
      this.end = end_limit;
    } else if (this.start < start_limit) {
      this.start = this.end - limit;
    } else {
      this.end = this.start + limit;
    }
  }
};


/**
 * Get the source text for a SourceLocation
 * @return {String}
 *     Source text for this location.
 */
SourceLocation.prototype.sourceText = function () {
  return this.script.source.substring(this.start, this.end);
};


/**
 * Class for a source slice. A source slice is a part of a script source with
 * the following properties:
 *   script        : script object for the source
 *   from_line     : line number for the first line in the slice
 *   to_line       : source line number for the last line in the slice
 *   from_position : position of the first character in the slice
 *   to_position   : position of the last character in the slice
 * The to_line and to_position are not included in the slice, that is the lines
 * in the slice are [from_line, to_line[. Likewise the characters in the slice
 * are [from_position, to_position[.
 * @param {Script} script The Script object for the source slice
 * @param {number} from_line
 * @param {number} to_line
 * @param {number} from_position
 * @param {number} to_position
 * @constructor
 */
function SourceSlice(script, from_line, to_line, from_position, to_position) {
  this.script = script;
  this.from_line = from_line;
  this.to_line = to_line;
  this.from_position = from_position;
  this.to_position = to_position;
}


/**
 * Get the source text for a SourceSlice
 * @return {String} Source text for this slice. The last line will include
 *     the line terminating characters (if any)
 */
SourceSlice.prototype.sourceText = function () {
  return this.script.source.substring(this.from_position, this.to_position);
};


// Returns the offset of the given position within the containing
// line.
function GetPositionInLine(message) {
  var location = message.script.locationFromPosition(message.startPos, false);
  if (location == null) return -1;
  location.restrict();
  return message.startPos - location.start;
}


function ErrorMessage(type, args, startPos, endPos, script, stackTrace) {
  this.startPos = startPos;
  this.endPos = endPos;
  this.type = type;
  this.args = args;
  this.script = script;
  this.stackTrace = stackTrace;
}


function MakeMessage(type, args, startPos, endPos, script, stackTrace) {
  return new ErrorMessage(type, args, startPos, endPos, script, stackTrace);
}


function GetStackTraceLine(recv, fun, pos, isGlobal) {
  try {
    return UnsafeGetStackTraceLine(recv, fun, pos, isGlobal);
  } catch (e) {
    return "<error: " + e + ">";
  }
}


function GetFunctionName(fun, recv) {
  var name = %FunctionGetName(fun);
  if (name) return name;
  for (var prop in recv) {
    if (recv[prop] === fun)
      return prop;
  }
  return "[anonymous]";
}


function UnsafeGetStackTraceLine(recv, fun, pos, isTopLevel) {
  var result = "";
  // The global frame has no meaningful function or receiver
  if (!isTopLevel) {
    // If the receiver is not the global object then prefix the
    // message send
    if (recv !== global)
      result += ToDetailString(recv) + ".";
    result += GetFunctionName(fun, recv);
  }
  if (pos != -1) {
    var script = %FunctionGetScript(fun);
    var file;
    if (script) {
      file = %FunctionGetScript(fun).data;
    }
    if (file) {
      var location = %FunctionGetScript(fun).locationFromPosition(pos, true);
      if (!isTopLevel) result += "(";
      result += file;
      if (location != null) {
        result += ":" + (location.line + 1) + ":" + (location.column + 1);
      }
      if (!isTopLevel) result += ")";
    }
  }
  return (result) ? "    at " + result : result;
}


// ----------------------------------------------------------------------------
// Error implementation

// If this object gets passed to an error constructor the error will
// get an accessor for .message that constructs a descriptive error
// message on access.
var kAddMessageAccessorsMarker = { };

// Defines accessors for a property that is calculated the first time
// the property is read and then replaces the accessor with the value.
// Also, setting the property causes the accessors to be deleted.
function DefineOneShotAccessor(obj, name, fun) {
  // Note that the accessors consistently operate on 'obj', not 'this'.
  // Since the object may occur in someone else's prototype chain we
  // can't rely on 'this' being the same as 'obj'.
  obj.__defineGetter__(name, function () {
    var value = fun(obj);
    obj[name] = value;
    return value;
  });
  obj.__defineSetter__(name, function (v) {
    delete obj[name];
    obj[name] = v;
  });
}

function DefineError(f) {
  // Store the error function in both the global object
  // and the runtime object. The function is fetched
  // from the runtime object when throwing errors from
  // within the runtime system to avoid strange side
  // effects when overwriting the error functions from
  // user code.
  var name = f.name;
  %SetProperty(global, name, f, DONT_ENUM);
  this['$' + name] = f;
  // Configure the error function.
  if (name == 'Error') {
    // The prototype of the Error object must itself be an error.
    // However, it can't be an instance of the Error object because
    // it hasn't been properly configured yet.  Instead we create a
    // special not-a-true-error-but-close-enough object.
    function ErrorPrototype() {}
    %FunctionSetPrototype(ErrorPrototype, $Object.prototype);
    %FunctionSetInstanceClassName(ErrorPrototype, 'Error');
    %FunctionSetPrototype(f, new ErrorPrototype());
  } else {
    %FunctionSetPrototype(f, new $Error());
  }
  %FunctionSetInstanceClassName(f, 'Error');
  %SetProperty(f.prototype, 'constructor', f, DONT_ENUM);
  f.prototype.name = name;
  %SetCode(f, function(m) {
    if (%IsConstructCall()) {
      if (m === kAddMessageAccessorsMarker) {
        DefineOneShotAccessor(this, 'message', function (obj) {
          return FormatMessage({type: obj.type, args: obj.arguments});
        });
      } else if (!IS_UNDEFINED(m)) {
        this.message = ToString(m);
      }
    } else {
      return new f(m);
    }
  });
}

$Math.__proto__ = global.Object.prototype;

DefineError(function Error() { });
DefineError(function TypeError() { });
DefineError(function RangeError() { });
DefineError(function SyntaxError() { });
DefineError(function ReferenceError() { });
DefineError(function EvalError() { });
DefineError(function URIError() { });

// Setup extra properties of the Error.prototype object.
$Error.prototype.message = '';

%SetProperty($Error.prototype, 'toString', function toString() {
  var type = this.type;
  if (type && !this.hasOwnProperty("message")) {
    return this.name + ": " + FormatMessage({ type: type, args: this.arguments });
  }
  var message = this.message;
  return this.name + (message ? (": " + message) : "");
}, DONT_ENUM);


// Boilerplate for exceptions for stack overflows. Used from
// Top::StackOverflow().
const kStackOverflowBoilerplate = MakeRangeError('stack_overflow', []);