dom/workers/JSSettings.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_dom_workerinternals_JSSettings_h
   8 #define mozilla_dom_workerinternals_JSSettings_h
   9
  10 #include <stdint.h>
  11
  12 #include "jsapi.h"
  13 #include "js/ContextOptions.h"
  14 #include "js/GCAPI.h"
  15 #include "mozilla/Maybe.h"
  16 #include "nsString.h"
  17 #include "nsTArray.h"
  18
  19 namespace mozilla {
  20 namespace dom {
  21 namespace workerinternals {
  22
  23 // Random unique constant to facilitate JSPrincipal debugging
  24 const uint32_t kJSPrincipalsDebugToken = 0x7e2df9d2;
  25
  26 struct JSSettings {
  27   enum {
  28     // All the GC parameters that we support.
  29     JSSettings_JSGC_MAX_BYTES = 0,
  30     JSSettings_JSGC_MAX_MALLOC_BYTES,
  31     JSSettings_JSGC_HIGH_FREQUENCY_TIME_LIMIT,
  32     JSSettings_JSGC_LOW_FREQUENCY_HEAP_GROWTH,
  33     JSSettings_JSGC_HIGH_FREQUENCY_HEAP_GROWTH_MIN,
  34     JSSettings_JSGC_HIGH_FREQUENCY_HEAP_GROWTH_MAX,
  35     JSSettings_JSGC_HIGH_FREQUENCY_LOW_LIMIT,
  36     JSSettings_JSGC_HIGH_FREQUENCY_HIGH_LIMIT,
  37     JSSettings_JSGC_ALLOCATION_THRESHOLD,
  38     JSSettings_JSGC_SLICE_TIME_BUDGET,
  39     JSSettings_JSGC_DYNAMIC_HEAP_GROWTH,
  40     JSSettings_JSGC_DYNAMIC_MARK_SLICE,
  41     // JSGC_MODE not supported
  42
  43     // This must be last so that we get an accurate count.
  44     kGCSettingsArraySize
  45   };
  46
  47   struct JSGCSetting {
  48     mozilla::Maybe<JSGCParamKey> key;
  49     uint32_t value;
  50
  51     JSGCSetting() : key(), value(0) {}
  52   };
  53
  54   // There are several settings that we know we need so it makes sense to
  55   // preallocate here.
  56   typedef JSGCSetting JSGCSettingsArray[kGCSettingsArraySize];
  57
  58   // Settings that change based on chrome/content context.
  59   struct JSContentChromeSettings {
  60     JS::RealmOptions realmOptions;
  61     int32_t maxScriptRuntime;
  62
  63     JSContentChromeSettings() : realmOptions(), maxScriptRuntime(0) {}
  64   };
  65
  66   JSContentChromeSettings chrome;
  67   JSContentChromeSettings content;
  68   JSGCSettingsArray gcSettings;
  69   JS::ContextOptions contextOptions;
  70
  71 #ifdef JS_GC_ZEAL
  72   uint8_t gcZeal;
  73   uint32_t gcZealFrequency;
  74 #endif
  75
  76   JSSettings()
  77 #ifdef JS_GC_ZEAL
  78       : gcZeal(0),
  79         gcZealFrequency(0)
  80 #endif
  81   {
  82     for (uint32_t index = 0; index < ArrayLength(gcSettings); index++) {
  83       new (gcSettings + index) JSGCSetting();
  84     }
  85   }
  86
  87   bool ApplyGCSetting(JSGCParamKey aKey, uint32_t aValue) {
  88     JSSettings::JSGCSetting* firstEmptySetting = nullptr;
  89     JSSettings::JSGCSetting* foundSetting = nullptr;
  90
  91     for (uint32_t index = 0; index < ArrayLength(gcSettings); index++) {
  92       JSSettings::JSGCSetting& setting = gcSettings[index];
  93       if (setting.key.isSome() && *setting.key == aKey) {
  94         foundSetting = &setting;
  95         break;
  96       }
  97       if (!firstEmptySetting && setting.key.isNothing()) {
  98         firstEmptySetting = &setting;
  99       }
 100     }
 101
 102     if (aValue) {
 103       if (!foundSetting) {
 104         foundSetting = firstEmptySetting;
 105         if (!foundSetting) {
 106           NS_ERROR("Not enough space for this value!");
 107           return false;
 108         }
 109       }
 110       foundSetting->key = mozilla::Some(aKey);
 111       foundSetting->value = aValue;
 112       return true;
 113     }
 114
 115     if (foundSetting) {
 116       foundSetting->key.reset();
 117       return true;
 118     }
 119
 120     return false;
 121   }
 122 };
 123
 124 }  // namespace workerinternals
 125 }  // namespace dom
 126 }  // namespace mozilla
 127
 128 #endif  // mozilla_dom_workerinternals_JSSettings_h