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