import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

xpcom/glue/nsCategoryCache.cpp

@@ -0,0 +1,149 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIObserverService.h"
+#include "mozilla/Services.h"
+#include "nsISupportsPrimitives.h"
+#include "nsIStringEnumerator.h"
+
+#include "nsXPCOMCID.h"
+
+#include "nsCategoryCache.h"
+
+nsCategoryObserver::nsCategoryObserver(const char* aCategory)
+  : mCategory(aCategory)
+  , mObserversRemoved(false)
+{
+  // First, enumerate the currently existing entries
+  nsCOMPtr<nsICategoryManager> catMan =
+    do_GetService(NS_CATEGORYMANAGER_CONTRACTID);
+  if (!catMan) {
+    return;
+  }
+
+  nsCOMPtr<nsISimpleEnumerator> enumerator;
+  nsresult rv = catMan->EnumerateCategory(aCategory,
+                                          getter_AddRefs(enumerator));
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  nsCOMPtr<nsIUTF8StringEnumerator> strings = do_QueryInterface(enumerator);
+  MOZ_ASSERT(strings);
+
+  bool more;
+  while (NS_SUCCEEDED(strings->HasMore(&more)) && more) {
+    nsAutoCString entryName;
+    strings->GetNext(entryName);
+
+    nsCString entryValue;
+    rv = catMan->GetCategoryEntry(aCategory,
+                                  entryName.get(),
+                                  getter_Copies(entryValue));
+    if (NS_SUCCEEDED(rv)) {
+      nsCOMPtr<nsISupports> service = do_GetService(entryValue.get());
+      if (service) {
+        mHash.Put(entryName, service);
+      }
+    }
+  }
+
+  // Now, listen for changes
+  nsCOMPtr<nsIObserverService> serv =
+    mozilla::services::GetObserverService();
+  if (serv) {
+    serv->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+    serv->AddObserver(this, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID, false);
+    serv->AddObserver(this, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID, false);
+    serv->AddObserver(this, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID, false);
+  }
+}
+
+nsCategoryObserver::~nsCategoryObserver()
+{
+}
+
+NS_IMPL_ISUPPORTS(nsCategoryObserver, nsIObserver)
+
+void
+nsCategoryObserver::ListenerDied()
+{
+  RemoveObservers();
+}
+
+void
+nsCategoryObserver::RemoveObservers()
+{
+  if (mObserversRemoved) {
+    return;
+  }
+
+  mObserversRemoved = true;
+  nsCOMPtr<nsIObserverService> obsSvc =
+    mozilla::services::GetObserverService();
+  if (obsSvc) {
+    obsSvc->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
+    obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID);
+    obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID);
+    obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID);
+  }
+}
+
+NS_IMETHODIMP
+nsCategoryObserver::Observe(nsISupports* aSubject, const char* aTopic,
+                            const char16_t* aData)
+{
+  if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
+    mHash.Clear();
+    RemoveObservers();
+
+    return NS_OK;
+  }
+
+  if (!aData ||
+      !nsDependentString(aData).Equals(NS_ConvertASCIItoUTF16(mCategory))) {
+    return NS_OK;
+  }
+
+  nsAutoCString str;
+  nsCOMPtr<nsISupportsCString> strWrapper(do_QueryInterface(aSubject));
+  if (strWrapper) {
+    strWrapper->GetData(str);
+  }
+
+  if (strcmp(aTopic, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID) == 0) {
+    // We may get an add notification even when we already have an entry. This
+    // is due to the notification happening asynchronously, so if the entry gets
+    // added and an nsCategoryObserver gets instantiated before events get
+    // processed, we'd get the notification for an existing entry.
+    // Do nothing in that case.
+    if (mHash.GetWeak(str)) {
+      return NS_OK;
+    }
+
+    nsCOMPtr<nsICategoryManager> catMan =
+      do_GetService(NS_CATEGORYMANAGER_CONTRACTID);
+    if (!catMan) {
+      return NS_OK;
+    }
+
+    nsCString entryValue;
+    catMan->GetCategoryEntry(mCategory.get(),
+                             str.get(),
+                             getter_Copies(entryValue));
+
+    nsCOMPtr<nsISupports> service = do_GetService(entryValue.get());
+
+    if (service) {
+      mHash.Put(str, service);
+    }
+  } else if (strcmp(aTopic, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID) == 0) {
+    mHash.Remove(str);
+  } else if (strcmp(aTopic, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID) == 0) {
+    mHash.Clear();
+  }
+  return NS_OK;
+}