Bug 810082 - Part 0.5 - Add script access event for CTP'd plugins r=joshmoz

content/base/public/nsIObjectLoadingContent.idl

@@ -21,7 +21,7 @@ interface nsIURI;
  * This interface represents a content node that loads objects.
  */
 
-[scriptable, uuid(a812424b-4820-4e28-96c8-dd2b69e36496)]
+[scriptable, uuid(649b8a75-8623-437f-ad30-0ac596c8452e)]
 interface nsIObjectLoadingContent : nsISupports
 {
   /**
@@ -130,6 +130,16 @@ interface nsIObjectLoadingContent : nsISupports
   [noscript] void syncStartPluginInstance();
   [noscript] void asyncStartPluginInstance();
 
+  /**
+   * Requests the plugin instance for scripting, attempting to spawn it if
+   * appropriate.
+   *
+   * The first time content js tries to access a pre-empted plugin
+   * (click-to-play or play preview), an event is dispatched.
+   */
+  [noscript] nsNPAPIPluginInstancePtr
+    scriptRequestPluginInstance(in bool callerIsContentJS);
+
   /**
    * The URL of the data/src loaded in the object. This may be null (i.e.
    * an <embed> with no src).

content/base/src/nsObjectLoadingContent.cpp

@@ -163,27 +163,31 @@ InDocCheckEvent::Run()
 }
 
 /**
- * A task for firing PluginNotFound and PluginBlocklisted DOM Events.
+ * Helper task for firing simple events
  */
-class nsPluginOutdatedEvent : public nsRunnable {
+class nsSimplePluginEvent : public nsRunnable {
 public:
-  nsPluginOutdatedEvent(nsIContent* aContent) : mContent(aContent) {}
+  nsSimplePluginEvent(nsIContent* aContent, const nsAString &aEvent)
+    : mContent(aContent),
+      mEvent(aEvent)
+  {}
 
-  ~nsPluginOutdatedEvent() {}
+  ~nsSimplePluginEvent() {}
 
   NS_IMETHOD Run();
 
 private:
   nsCOMPtr<nsIContent> mContent;
+  nsString mEvent;
 };
 
 NS_IMETHODIMP
-nsPluginOutdatedEvent::Run()
+nsSimplePluginEvent::Run()
 {
-  LOG(("OBJLC [%p]: nsPluginOutdatedEvent firing", mContent.get()));
+  LOG(("OBJLC [%p]: nsSimplePluginEvent firing event \"%s\"", mContent.get(),
+       mEvent.get()));
   nsContentUtils::DispatchTrustedEvent(mContent->GetDocument(), mContent,
-                                       NS_LITERAL_STRING("PluginOutdated"),
-                                       true, true);
+                                       mEvent, true, true);
   return NS_OK;
 }
 
@@ -631,6 +635,7 @@ nsObjectLoadingContent::nsObjectLoadingContent()
   , mPlayPreviewCanceled(false)
   , mIsStopping(false)
   , mIsLoading(false)
+  , mScriptRequested(false)
   , mSrcStreamLoading(false) {}
 
 nsObjectLoadingContent::~nsObjectLoadingContent()
@@ -748,12 +753,13 @@ nsObjectLoadingContent::InstantiatePluginInstance()
                                          EmptyString(), &blockState);
       if (blockState == nsIBlocklistService::STATE_OUTDATED) {
         // Fire plugin outdated event if necessary
-        LOG(("OBJLC [%p]: Dispatching nsPluginOutdatedEvent for content %p\n",
+        LOG(("OBJLC [%p]: Dispatching plugin outdated event for content %p\n",
              this));
-        nsCOMPtr<nsIRunnable> ev = new nsPluginOutdatedEvent(thisContent);
+        nsCOMPtr<nsIRunnable> ev = new nsSimplePluginEvent(thisContent,
+                                                     NS_LITERAL_STRING("PluginOutdated"));
         nsresult rv = NS_DispatchToCurrentThread(ev);
         if (NS_FAILED(rv)) {
-          NS_WARNING("failed to dispatch nsPluginOutdatedEvent");
+          NS_WARNING("failed to dispatch nsSimplePluginEvent");
         }
       }
     }
@@ -2013,6 +2019,8 @@ nsObjectLoadingContent::UnloadObject(bool aResetState)
     mOriginalContentType.Truncate();
   }
 
+  mScriptRequested = false;
+
   // This call should be last as it may re-enter
   StopPluginInstance();
 }
@@ -2183,6 +2191,45 @@ nsObjectLoadingContent::PluginCrashed(nsIPluginTag* aPluginTag,
   return NS_OK;
 }
 
+NS_IMETHODIMP
+nsObjectLoadingContent::ScriptRequestPluginInstance(bool aCallerIsContentJS,
+                                                    nsNPAPIPluginInstance **aResult)
+{
+  nsCOMPtr<nsIContent> thisContent =
+    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
+
+  *aResult = nullptr;
+
+  // The first time content script attempts to access placeholder content, fire
+  // an event.  Fallback types >= eFallbackClickToPlay are plugin-replacement
+  // types, see header.
+  if (aCallerIsContentJS && !mScriptRequested &&
+      InActiveDocument(thisContent) && mType == eType_Null &&
+      mFallbackType >= eFallbackClickToPlay) {
+    nsCOMPtr<nsIRunnable> ev =
+      new nsSimplePluginEvent(thisContent,
+                              NS_LITERAL_STRING("PluginScripted"));
+    nsresult rv = NS_DispatchToCurrentThread(ev);
+    if (NS_FAILED(rv)) {
+      NS_NOTREACHED("failed to dispatch PluginScripted event");
+    }
+    mScriptRequested = true;
+  } else if (mType == eType_Plugin && !mInstanceOwner &&
+             nsContentUtils::IsSafeToRunScript() &&
+             InActiveDocument(thisContent)) {
+    // If we're configured as a plugin in an active document and it's safe to
+    // run scripts right now, try spawning synchronously
+    SyncStartPluginInstance();
+  }
+
+  if (mInstanceOwner) {
+    return mInstanceOwner->GetInstance(aResult);
+  }
+
+  // Note that returning a null plugin is expected (and happens often)
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsObjectLoadingContent::SyncStartPluginInstance()
 {

content/base/src/nsObjectLoadingContent.h

@@ -437,12 +437,16 @@ class nsObjectLoadingContent : public nsImageLoadingContent
     // Protects LoadObject from re-entry
     bool                        mIsLoading : 1;
 
+    // For plugin stand-in types (click-to-play, play preview, ...) tracks
+    // whether content js has tried to access the plugin script object.
+    bool                        mScriptRequested : 1;
+
     // Used to track when we might try to instantiate a plugin instance based on
     // a src data stream being delivered to this object. When this is true we
     // don't want plugin instance instantiation code to attempt to load src data
     // again or we'll deliver duplicate streams. Should be cleared when we are
     // not loading src data.
-    bool mSrcStreamLoading;
+    bool                        mSrcStreamLoading : 1;
 
 
     nsWeakFrame                 mPrintFrame;

dom/base/nsDOMClassInfo.cpp

@@ -9563,6 +9563,7 @@ nsHTMLSelectElementSH::SetProperty(nsIXPConnectWrappedNative *wrapper,
 nsresult
 nsHTMLPluginObjElementSH::GetPluginInstanceIfSafe(nsIXPConnectWrappedNative *wrapper,
                                                   JSObject *obj,
+                                                  JSContext *cx,
                                                   nsNPAPIPluginInstance **_result)
 {
   *_result = nullptr;
@@ -9573,22 +9574,11 @@ nsHTMLPluginObjElementSH::GetPluginInstanceIfSafe(nsIXPConnectWrappedNative *wra
   nsCOMPtr<nsIObjectLoadingContent> objlc(do_QueryInterface(content));
   NS_ASSERTION(objlc, "Object nodes must implement nsIObjectLoadingContent");
 
-  nsresult rv = objlc->GetPluginInstance(_result);
-  if (NS_SUCCEEDED(rv) && *_result) {
-    return rv;
-  }
-
-  // If it's not safe to run script we'll only return the instance if it exists.
-  // Ditto if the document is inactive.
-  if (!nsContentUtils::IsSafeToRunScript() || !content->OwnerDoc()->IsActive()) {
-    return rv;
-  }
-
-  // We don't care if this actually starts the plugin or not, we just want to
-  // try to start it now if possible.
-  objlc->SyncStartPluginInstance();
-
-  return objlc->GetPluginInstance(_result);
+  bool callerIsContentJS = (!xpc::AccessCheck::callerIsChrome() &&
+                            !xpc::AccessCheck::callerIsXBL(cx) &&
+                            js::IsContextRunningJS(cx));
+  return objlc->ScriptRequestPluginInstance(callerIsContentJS,
+                                            _result);
 }
 
 class nsPluginProtoChainInstallRunner MOZ_FINAL : public nsIRunnable
@@ -9649,7 +9639,7 @@ nsHTMLPluginObjElementSH::SetupProtoChain(nsIXPConnectWrappedNative *wrapper,
   JSAutoCompartment ac(cx, obj);
 
   nsRefPtr<nsNPAPIPluginInstance> pi;
-  nsresult rv = GetPluginInstanceIfSafe(wrapper, obj, getter_AddRefs(pi));
+  nsresult rv = GetPluginInstanceIfSafe(wrapper, obj, cx, getter_AddRefs(pi));
   NS_ENSURE_SUCCESS(rv, rv);
 
   if (!pi) {
@@ -9855,7 +9845,7 @@ nsHTMLPluginObjElementSH::Call(nsIXPConnectWrappedNative *wrapper,
                                jsval *argv, jsval *vp, bool *_retval)
 {
   nsRefPtr<nsNPAPIPluginInstance> pi;
-  nsresult rv = GetPluginInstanceIfSafe(wrapper, obj, getter_AddRefs(pi));
+  nsresult rv = GetPluginInstanceIfSafe(wrapper, obj, cx, getter_AddRefs(pi));
   NS_ENSURE_SUCCESS(rv, rv);
 
   // If obj is a native wrapper, or if there's no plugin around for
@@ -9922,7 +9912,7 @@ nsHTMLPluginObjElementSH::NewResolve(nsIXPConnectWrappedNative *wrapper,
   // possible.
 
   nsRefPtr<nsNPAPIPluginInstance> pi;
-  nsresult rv = GetPluginInstanceIfSafe(wrapper, obj, getter_AddRefs(pi));
+  nsresult rv = GetPluginInstanceIfSafe(wrapper, obj, cx, getter_AddRefs(pi));
   NS_ENSURE_SUCCESS(rv, rv);
 
   return nsElementSH::NewResolve(wrapper, cx, obj, id, flags, objp,

dom/base/nsDOMClassInfo.h

@@ -848,6 +848,7 @@ protected:
 
   static nsresult GetPluginInstanceIfSafe(nsIXPConnectWrappedNative *aWrapper,
                                           JSObject *obj,
+                                          JSContext *cx,
                                           nsNPAPIPluginInstance **aResult);
 
   static nsresult GetPluginJSObject(JSContext *cx, JSObject *obj,