debug-delay.js.svn-base

Google浏览器V8内核代码

// 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.

// Default number of frames to include in the response to backtrace request.
const kDefaultBacktraceLength = 10;

const Debug = {};

// Regular expression to skip "crud" at the beginning of a source line which is
// not really code. Currently the regular expression matches whitespace and
// comments.
const sourceLineBeginningSkip = /^(?:[ \v\h]*(?:\/\*.*?\*\/)*)*/;

// Debug events which can occour in the V8 JavaScript engine. These originate
// from the API include file debug.h.
Debug.DebugEvent = { Break: 1,
                     Exception: 2,
                     NewFunction: 3,
                     BeforeCompile: 4,
                     AfterCompile: 5 };

// Types of exceptions that can be broken upon.
Debug.ExceptionBreak = { All : 0,
                         Uncaught: 1 };

// The different types of steps.
Debug.StepAction = { StepOut: 0,
                     StepNext: 1,
                     StepIn: 2,
                     StepMin: 3,
                     StepInMin: 4 };

// The different types of scripts matching enum ScriptType in objects.h.
Debug.ScriptType = { Native: 0,
                     Extension: 1,
                     Normal: 2 };

function ScriptTypeFlag(type) {
  return (1 << type);
}

// Globals.
var next_response_seq = 0;
var next_break_point_number = 1;
var break_points = [];
var script_break_points = [];


// Create a new break point object and add it to the list of break points.
function MakeBreakPoint(source_position, opt_line, opt_column, opt_script_break_point) {
  var break_point = new BreakPoint(source_position, opt_line, opt_column, opt_script_break_point);
  break_points.push(break_point);
  return break_point;
};


// Object representing a break point.
// NOTE: This object does not have a reference to the function having break
// point as this would cause function not to be garbage collected when it is
// not used any more. We do not want break points to keep functions alive.
function BreakPoint(source_position, opt_line, opt_column, opt_script_break_point) {
  this.source_position_ = source_position;
  this.source_line_ = opt_line;
  this.source_column_ = opt_column;
  if (opt_script_break_point) {
    this.script_break_point_ = opt_script_break_point;
  } else {
    this.number_ = next_break_point_number++;
  }
  this.hit_count_ = 0;
  this.active_ = true;
  this.condition_ = null;
  this.ignoreCount_ = 0;
};


BreakPoint.prototype.number = function() {
  return this.number_;
};


BreakPoint.prototype.func = function() {
  return this.func_;
};


BreakPoint.prototype.source_position = function() {
  return this.source_position_;
};


BreakPoint.prototype.hit_count = function() {
  return this.hit_count_;
};


BreakPoint.prototype.active = function() {
  if (this.script_break_point()) {
    return this.script_break_point().active();
  }
  return this.active_;
};


BreakPoint.prototype.condition = function() {
  if (this.script_break_point() && this.script_break_point().condition()) {
    return this.script_break_point().condition();
  }
  return this.condition_;
};


BreakPoint.prototype.ignoreCount = function() {
  return this.ignoreCount_;
};


BreakPoint.prototype.script_break_point = function() {
  return this.script_break_point_;
};


BreakPoint.prototype.enable = function() {
  this.active_ = true;
};


BreakPoint.prototype.disable = function() {
  this.active_ = false;
};


BreakPoint.prototype.setCondition = function(condition) {
  this.condition_ = condition;
};


BreakPoint.prototype.setIgnoreCount = function(ignoreCount) {
  this.ignoreCount_ = ignoreCount;
};


BreakPoint.prototype.isTriggered = function(exec_state) {
  // Break point not active - not triggered.
  if (!this.active()) return false;

  // Check for conditional break point.
  if (this.condition()) {
    // If break point has condition try to evaluate it in the top frame.
    try {
      var mirror = exec_state.frame(0).evaluate(this.condition());
      // If no sensible mirror or non true value break point not triggered.
      if (!(mirror instanceof ValueMirror) || !%ToBoolean(mirror.value_)) {
        return false;
      }
    } catch (e) {
      // Exception evaluating condition counts as not triggered.
      return false;
    }
  }

  // Update the hit count.
  this.hit_count_++;
  if (this.script_break_point_) {
    this.script_break_point_.hit_count_++;
  }

  // If the break point has an ignore count it is not triggered.
  if (this.ignoreCount_ > 0) {
    this.ignoreCount_--;
    return false;
  }

  // Break point triggered.
  return true;
};


// Function called from the runtime when a break point is hit. Returns true if
// the break point is triggered and supposed to break execution.
function IsBreakPointTriggered(break_id, break_point) {
  return break_point.isTriggered(MakeExecutionState(break_id));
};


// Object representing a script break point. The script is referenced by its
// script name and the break point is represented as line and column.
function ScriptBreakPoint(script_name, opt_line, opt_column) {
  this.script_name_ = script_name;
  this.line_ = opt_line || 0;
  this.column_ = opt_column;
  this.hit_count_ = 0;
  this.active_ = true;
  this.condition_ = null;
  this.ignoreCount_ = 0;
};


ScriptBreakPoint.prototype.number = function() {
  return this.number_;
};


ScriptBreakPoint.prototype.script_name = function() {
  return this.script_name_;
};


ScriptBreakPoint.prototype.line = function() {
  return this.line_;
};


ScriptBreakPoint.prototype.column = function() {
  return this.column_;
};


ScriptBreakPoint.prototype.hit_count = function() {
  return this.hit_count_;
};


ScriptBreakPoint.prototype.active = function() {
  return this.active_;
};


ScriptBreakPoint.prototype.condition = function() {
  return this.condition_;
};


ScriptBreakPoint.prototype.ignoreCount = function() {
  return this.ignoreCount_;
};


ScriptBreakPoint.prototype.enable = function() {
  this.active_ = true;
};


ScriptBreakPoint.prototype.disable = function() {
  this.active_ = false;
};


ScriptBreakPoint.prototype.setCondition = function(condition) {
  this.condition_ = condition;
};


ScriptBreakPoint.prototype.setIgnoreCount = function(ignoreCount) {
  this.ignoreCount_ = ignoreCount;

  // Set ignore count on all break points created from this script break point.
  for (var i = 0; i < break_points.length; i++) {
    if (break_points[i].script_break_point() === this) {
      break_points[i].setIgnoreCount(ignoreCount);
    }
  }
};


// Check whether a script matches this script break point. Currently this is
// only based on script name.
ScriptBreakPoint.prototype.matchesScript = function(script) {
  return this.script_name_ == script.name &&
         script.line_offset <= this.line_  &&
         this.line_ < script.line_offset + script.lineCount();
};


// Set the script break point in a script.
ScriptBreakPoint.prototype.set = function (script) {
  var column = this.column();
  var line = this.line();
  // If the column is undefined the break is on the line. To help locate the
  // first piece of breakable code on the line try to find the column on the
  // line which contains some source.
  if (IS_UNDEFINED(column)) {
    var source_line = script.sourceLine(this.line());

    // Allocate array for caching the columns where the actual source starts.
    if (!script.sourceColumnStart_) {
      script.sourceColumnStart_ = new Array(script.lineCount());
    }
    
    // Fill cache if needed and get column where the actual source starts.
    if (IS_UNDEFINED(script.sourceColumnStart_[line])) {
      script.sourceColumnStart_[line] =
          source_line.match(sourceLineBeginningSkip)[0].length;
    }
    column = script.sourceColumnStart_[line];
  }

  // Convert the line and column into an absolute position within the script.
  var pos = Debug.findScriptSourcePosition(script, this.line(), column);
  
  // Create a break point object and set the break point.
  break_point = MakeBreakPoint(pos, this.line(), this.column(), this);
  break_point.setIgnoreCount(this.ignoreCount());
  %SetScriptBreakPoint(script, pos, break_point);

  return break_point;
};


// Clear all the break points created from this script break point
ScriptBreakPoint.prototype.clear = function () {
  var remaining_break_points = [];
  for (var i = 0; i < break_points.length; i++) {
    if (break_points[i].script_break_point() &&
        break_points[i].script_break_point() === this) {
      %ClearBreakPoint(break_points[i]);
    } else {
      remaining_break_points.push(break_points[i]);
    }
  }
  break_points = remaining_break_points;
};


// Function called from runtime when a new script is compiled to set any script
// break points set in this script.
function UpdateScriptBreakPoints(script) {
  for (var i = 0; i < script_break_points.length; i++) {
    if (script_break_points[i].script_name() == script.name) {
      script_break_points[i].set(script);
    }
  }
};


// Function called from the runtime to handle a debug request receiced from the
// debugger. When this function is called the debugger is in the broken state
// reflected by the exec_state parameter. When pending requests are handled the
// parameter stopping indicate the expected running state.
function ProcessDebugRequest(exec_state, request, stopping) {
  return exec_state.debugCommandProcessor().processDebugJSONRequest(request, stopping);
}


Debug.addListener = function(listener, opt_data) {
  if (!IS_FUNCTION(listener)) throw new Error('Parameters have wrong types.');
  %AddDebugEventListener(listener, opt_data);
};

Debug.removeListener = function(listener) {
  if (!IS_FUNCTION(listener)) throw new Error('Parameters have wrong types.');
  %RemoveDebugEventListener(listener);
};

Debug.breakExecution = function(f) {
  %Break();
};

Debug.breakLocations = function(f) {
  if (!IS_FUNCTION(f)) throw new Error('Parameters have wrong types.');
  return %GetBreakLocations(f);
};

// Returns a Script object. If the parameter is a function the return value
// is the script in which the function is defined. If the parameter is a string
// the return value is the script for which the script name has that string
// value.  If it is a regexp and there is a unique script whose name matches
// we return that, otherwise undefined.
Debug.findScript = function(func_or_script_name) {
  if (IS_FUNCTION(func_or_script_name)) {
    return %FunctionGetScript(func_or_script_name);
  } else if (IS_REGEXP(func_or_script_name)) {
    var scripts = Debug.scripts();
    var last_result = null;
    var result_count = 0;
    for (var i in scripts) {
      var script = scripts[i];
      if (func_or_script_name.test(script.name)) {
        last_result = script;
        result_count++;
      }
    }
    // Return the unique script matching the regexp.  If there are more
    // than one we don't return a value since there is no good way to
    // decide which one to return.  Returning a "random" one, say the
    // first, would introduce nondeterminism (or something close to it)
    // because the order is the heap iteration order.
    if (result_count == 1) {
      return last_result;
    } else {
      return undefined;
    }
  } else {
    return %GetScript(func_or_script_name);
  }
};

// Returns the script source. If the parameter is a function the return value
// is the script source for the script in which the function is defined. If the
// parameter is a string the return value is the script for which the script
// name has that string value.
Debug.scriptSource = function(func_or_script_name) {
  return this.findScript(func_or_script_name).source;
};

Debug.source = function(f) {
  if (!IS_FUNCTION(f)) throw new Error('Parameters have wrong types.');
  return %FunctionGetSourceCode(f);
};

Debug.assembler = function(f) {
  if (!IS_FUNCTION(f)) throw new Error('Parameters have wrong types.');
  return %FunctionGetAssemblerCode(f);
};

Debug.sourcePosition = function(f) {
  if (!IS_FUNCTION(f)) throw new Error('Parameters have wrong types.');
  return %FunctionGetScriptSourcePosition(f);
};

Debug.findFunctionSourcePosition = function(func, opt_line, opt_column) {
  var script = %FunctionGetScript(func);
  var script_offset = %FunctionGetScriptSourcePosition(func);
  return script.locationFromLine(opt_line, opt_column, script_offset).position;
}


// Returns the character position in a script based on a line number and an
// optional position within that line.
Debug.findScriptSourcePosition = function(script, opt_line, opt_column) {
  return script.locationFromLine(opt_line, opt_column).position;
}


Debug.findBreakPoint = function(break_point_number, remove) {
  var break_point;
  for (var i = 0; i < break_points.length; i++) {
    if (break_points[i].number() == break_point_number) {
      break_point = break_points[i];
      // Remove the break point from the list if requested.
      if (remove) {
        break_points.splice(i, 1);
      }
      break;
    }
  }
  if (break_point) {
    return break_point;
  } else {
    return this.findScriptBreakPoint(break_point_number, remove);
  }
};


Debug.setBreakPoint = function(func, opt_line, opt_column, opt_condition) {
  if (!IS_FUNCTION(func)) throw new Error('Parameters have wrong types.');
  var source_position = this.findFunctionSourcePosition(func, opt_line, opt_column) -
                        this.sourcePosition(func);
  // Find the script for the function.
  var script = %FunctionGetScript(func);
  // If the script for the function has a name convert this to a script break
  // point.
  if (script && script.name) {
    // Adjust the source position to be script relative.
    source_position += %FunctionGetScriptSourcePosition(func);
    // Find line and column for the position in the script and set a script
    // break point from that.
    var location = script.locationFromPosition(source_position);
    return this.setScriptBreakPoint(script.name,
                                    location.line, location.column,
                                    opt_condition);
  } else {
    // Set a break point directly on the function.
    var break_point = MakeBreakPoint(source_position, opt_line, opt_column);
    %SetFunctionBreakPoint(func, source_position, break_point);
    break_point.setCondition(opt_condition);
    return break_point.number();
  }
};


Debug.enableBreakPoint = function(break_point_number) {
  var break_point = this.findBreakPoint(break_point_number, false);
  break_point.enable();