js/loader/LoadedScript.cpp

   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
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "LoadedScript.h"
   8
   9 #include "mozilla/HoldDropJSObjects.h"
  10
  11 #include "jsfriendapi.h"
  12 #include "js/Modules.h"  // JS::{Get,Set}ModulePrivate
  13
  14 namespace JS::loader {
  15
  16 //////////////////////////////////////////////////////////////
  17 // LoadedScript
  18 //////////////////////////////////////////////////////////////
  19
  20 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(LoadedScript)
  21   NS_INTERFACE_MAP_ENTRY(nsISupports)
  22 NS_INTERFACE_MAP_END
  23
  24 NS_IMPL_CYCLE_COLLECTION_CLASS(LoadedScript)
  25
  26 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(LoadedScript)
  27   NS_IMPL_CYCLE_COLLECTION_UNLINK(mFetchOptions)
  28   NS_IMPL_CYCLE_COLLECTION_UNLINK(mBaseURL)
  29 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  30
  31 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(LoadedScript)
  32   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFetchOptions)
  33 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  34
  35 NS_IMPL_CYCLE_COLLECTING_ADDREF(LoadedScript)
  36 NS_IMPL_CYCLE_COLLECTING_RELEASE(LoadedScript)
  37
  38 LoadedScript::LoadedScript(ScriptKind aKind, ScriptFetchOptions* aFetchOptions,
  39                            nsIURI* aBaseURL)
  40     : mKind(aKind), mFetchOptions(aFetchOptions), mBaseURL(aBaseURL) {
  41   MOZ_ASSERT(mFetchOptions);
  42   MOZ_ASSERT(mBaseURL);
  43 }
  44
  45 LoadedScript::~LoadedScript() { mozilla::DropJSObjects(this); }
  46
  47 void LoadedScript::AssociateWithScript(JSScript* aScript) {
  48   // Set a JSScript's private value to point to this object. The JS engine will
  49   // increment our reference count by calling HostAddRefTopLevelScript(). This
  50   // is decremented by HostReleaseTopLevelScript() below when the JSScript dies.
  51
  52   MOZ_ASSERT(JS::GetScriptPrivate(aScript).isUndefined());
  53   JS::SetScriptPrivate(aScript, JS::PrivateValue(this));
  54 }
  55
  56 inline void CheckModuleScriptPrivate(LoadedScript* script,
  57                                      const JS::Value& aPrivate) {
  58 #ifdef DEBUG
  59   if (script->IsModuleScript()) {
  60     JSObject* module = script->AsModuleScript()->mModuleRecord.unbarrieredGet();
  61     MOZ_ASSERT_IF(module, JS::GetModulePrivate(module) == aPrivate);
  62   }
  63 #endif
  64 }
  65
  66 void HostAddRefTopLevelScript(const JS::Value& aPrivate) {
  67   // Increment the reference count of a LoadedScript object that is now pointed
  68   // to by a JSScript. The reference count is decremented by
  69   // HostReleaseTopLevelScript() below.
  70
  71   auto script = static_cast<LoadedScript*>(aPrivate.toPrivate());
  72   CheckModuleScriptPrivate(script, aPrivate);
  73   script->AddRef();
  74 }
  75
  76 void HostReleaseTopLevelScript(const JS::Value& aPrivate) {
  77   // Decrement the reference count of a LoadedScript object that was pointed to
  78   // by a JSScript. The reference count was originally incremented by
  79   // HostAddRefTopLevelScript() above.
  80
  81   auto script = static_cast<LoadedScript*>(aPrivate.toPrivate());
  82   CheckModuleScriptPrivate(script, aPrivate);
  83   script->Release();
  84 }
  85
  86 //////////////////////////////////////////////////////////////
  87 // EventScript
  88 //////////////////////////////////////////////////////////////
  89
  90 EventScript::EventScript(ScriptFetchOptions* aFetchOptions, nsIURI* aBaseURL)
  91     : LoadedScript(ScriptKind::eEvent, aFetchOptions, aBaseURL) {}
  92
  93 //////////////////////////////////////////////////////////////
  94 // ClassicScript
  95 //////////////////////////////////////////////////////////////
  96
  97 ClassicScript::ClassicScript(ScriptFetchOptions* aFetchOptions,
  98                              nsIURI* aBaseURL)
  99     : LoadedScript(ScriptKind::eClassic, aFetchOptions, aBaseURL) {}
 100
 101 //////////////////////////////////////////////////////////////
 102 // ModuleScript
 103 //////////////////////////////////////////////////////////////
 104
 105 NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(ModuleScript, LoadedScript)
 106
 107 NS_IMPL_CYCLE_COLLECTION_CLASS(ModuleScript)
 108
 109 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(ModuleScript, LoadedScript)
 110   tmp->UnlinkModuleRecord();
 111   tmp->mParseError.setUndefined();
 112   tmp->mErrorToRethrow.setUndefined();
 113 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 114
 115 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(ModuleScript, LoadedScript)
 116 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 117
 118 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(ModuleScript, LoadedScript)
 119   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mModuleRecord)
 120   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mParseError)
 121   NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mErrorToRethrow)
 122 NS_IMPL_CYCLE_COLLECTION_TRACE_END
 123
 124 ModuleScript::ModuleScript(ScriptFetchOptions* aFetchOptions, nsIURI* aBaseURL)
 125     : LoadedScript(ScriptKind::eModule, aFetchOptions, aBaseURL),
 126       mDebuggerDataInitialized(false) {
 127   MOZ_ASSERT(!ModuleRecord());
 128   MOZ_ASSERT(!HasParseError());
 129   MOZ_ASSERT(!HasErrorToRethrow());
 130 }
 131
 132 void ModuleScript::Shutdown() {
 133   if (mModuleRecord) {
 134     JS::ClearModuleEnvironment(mModuleRecord);
 135   }
 136
 137   UnlinkModuleRecord();
 138 }
 139
 140 void ModuleScript::UnlinkModuleRecord() {
 141   // Remove the module record's pointer to this object if present and decrement
 142   // our reference count. The reference is added by SetModuleRecord() below.
 143   //
 144   // This takes care not to trigger gray unmarking because this takes a lot of
 145   // time when we're tearing down the entire page. This is safe because we are
 146   // only writing undefined into the module private, so it won't create any
 147   // black-gray edges.
 148   if (mModuleRecord) {
 149     JSObject* module = mModuleRecord.unbarrieredGet();
 150     MOZ_ASSERT(JS::GetModulePrivate(module).toPrivate() == this);
 151     JS::ClearModulePrivate(module);
 152     mModuleRecord = nullptr;
 153   }
 154 }
 155
 156 ModuleScript::~ModuleScript() {
 157   // The object may be destroyed without being unlinked first.
 158   UnlinkModuleRecord();
 159 }
 160
 161 void ModuleScript::SetModuleRecord(JS::Handle<JSObject*> aModuleRecord) {
 162   MOZ_ASSERT(!mModuleRecord);
 163   MOZ_ASSERT_IF(IsModuleScript(), !AsModuleScript()->HasParseError());
 164   MOZ_ASSERT_IF(IsModuleScript(), !AsModuleScript()->HasErrorToRethrow());
 165
 166   mModuleRecord = aModuleRecord;
 167
 168   // Make module's host defined field point to this object. The JS engine will
 169   // increment our reference count by calling HostAddRefTopLevelScript(). This
 170   // is decremented when the field is cleared in UnlinkModuleRecord() above or
 171   // when the module record dies.
 172   MOZ_ASSERT(JS::GetModulePrivate(mModuleRecord).isUndefined());
 173   JS::SetModulePrivate(mModuleRecord, JS::PrivateValue(this));
 174
 175   mozilla::HoldJSObjects(this);
 176 }
 177
 178 void ModuleScript::SetParseError(const JS::Value& aError) {
 179   MOZ_ASSERT(!aError.isUndefined());
 180   MOZ_ASSERT(!HasParseError());
 181   MOZ_ASSERT(!HasErrorToRethrow());
 182
 183   UnlinkModuleRecord();
 184   mParseError = aError;
 185   mozilla::HoldJSObjects(this);
 186 }
 187
 188 void ModuleScript::SetErrorToRethrow(const JS::Value& aError) {
 189   MOZ_ASSERT(!aError.isUndefined());
 190
 191   // This is only called after SetModuleRecord() or SetParseError() so we don't
 192   // need to call HoldJSObjects() here.
 193   MOZ_ASSERT(ModuleRecord() || HasParseError());
 194
 195   mErrorToRethrow = aError;
 196 }
 197
 198 void ModuleScript::SetDebuggerDataInitialized() {
 199   MOZ_ASSERT(ModuleRecord());
 200   MOZ_ASSERT(!mDebuggerDataInitialized);
 201
 202   mDebuggerDataInitialized = true;
 203 }
 204
 205 }  // namespace JS::loader