Add option to disable MirrorCache.

src/mirror-debugger.js

 // Copyright 2006-2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Handle id counters.
 var next_handle_ = 0;
 var next_transient_handle_ = -1;
 
 // Mirror cache.
 var mirror_cache_ = [];
+var mirror_cache_enabled_ = true;
+
+
+function ToggleMirrorCache(value) {
+  mirror_cache_enabled_ = value;
+  next_handle_ = 0;
+  mirror_cache_ = [];
+}
 
 
 /**
  * Clear the mirror handle cache.
  */
 function ClearMirrorCache() {
   next_handle_ = 0;
   mirror_cache_ = [];
 }
 
@@ skipping 16 matching lines @@
  *
  * @param {value or Object} value the value or object to retreive the mirror for
  * @param {boolean} transient indicate whether this object is transient and
  *    should not be added to the mirror cache. The default is not transient.
  * @returns {Mirror} the mirror reflects the passed value or object
  */
 function MakeMirror(value, opt_transient) {
   var mirror;
 
   // Look for non transient mirrors in the mirror cache.
-  if (!opt_transient) {
+  if (!opt_transient && mirror_cache_enabled_) {
     for (id in mirror_cache_) {
       mirror = mirror_cache_[id];
       if (mirror.value() === value) {
         return mirror;
       }
       // Special check for NaN as NaN == NaN is false.
       if (mirror.isNumber() && isNaN(mirror.value()) &&
           typeof value == 'number' && isNaN(value)) {
         return mirror;
       }
@@ skipping 23 matching lines @@
   } else if (IS_ERROR(value)) {
     mirror = new ErrorMirror(value);
   } else if (IS_SCRIPT(value)) {
     mirror = new ScriptMirror(value);
   } else if (ObjectIsPromise(value)) {
     mirror = new PromiseMirror(value);
   } else {
     mirror = new ObjectMirror(value, OBJECT_TYPE, opt_transient);
   }
 
-  mirror_cache_[mirror.handle()] = mirror;
+  if (mirror_cache_enabled_) mirror_cache_[mirror.handle()] = mirror;
   return mirror;
 }
 
 
 /**
  * Returns the mirror for a specified mirror handle.
  *
  * @param {number} handle the handle to find the mirror for
  * @returns {Mirror or undefiend} the mirror with the requested handle or
  *     undefined if no mirror with the requested handle was found
  */
 function LookupMirror(handle) {
-  return mirror_cache_[handle];
+  return mirror_cache_enabled_ ? mirror_cache_[handle] : UNDEFINED;

[yurys, 2014/06/03 13:27:18]

I'd rather we threw an exception if mirror cache is disabled.

[Yang, 2014/06/03 14:22:05]

Done.

 }
 
 
 /**
  * Returns the mirror for the undefined value.
  *
  * @returns {Mirror} the mirror reflects the undefined value
  */
 function GetUndefinedMirror() {
   return MakeMirror(UNDEFINED);
@@ skipping 302 matching lines @@
  */
 Mirror.prototype.isScope = function() {
   return this instanceof ScopeMirror;
 };
 
 
 /**
  * Allocate a handle id for this object.
  */
 Mirror.prototype.allocateHandle_ = function() {
-  this.handle_ = next_handle_++;
+  if (mirror_cache_enabled_) this.handle_ = next_handle_++;
 };
 
 
 /**
  * Allocate a transient handle id for this object. Transient handles are
  * negative.
  */
 Mirror.prototype.allocateTransientHandle_ = function() {
   this.handle_ = next_transient_handle_--;
 };
@@ skipping 2340 matching lines @@
   }
   if (!NUMBER_IS_FINITE(value)) {
     if (value > 0) {
       return 'Infinity';
     } else {
       return '-Infinity';
     }
   }
   return value;
 }