bug 246085 nsCategoryManager should notify observers when items are added/removed from categories

r=dougt sr=darin a=asa

xpcom/build/nsXPCOM.h

@@ -308,6 +308,37 @@ NS_Free(void* ptr);
  */
 #define NS_XPCOM_SHUTDOWN_OBSERVER_ID "xpcom-shutdown"
 
+/**
+ * This topic is notified when an entry was added to a category in the
+ * category manager. The subject of the notification will be the name of
+ * the added entry as an nsISupportsCString, and the data will be the
+ * name of the category.
+ *
+ * @status FROZEN
+ */
+#define NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID \
+  "xpcom-category-entry-added"
+
+/**
+ * This topic is notified when an entry was removed from a category in the
+ * category manager. The subject of the notification will be the name of
+ * the removed entry as an nsISupportsCString, and the data will be the
+ * name of the category.
+ *
+ * @status FROZEN
+ */
+#define NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID \
+  "xpcom-category-entry-removed"
+
+/**
+ * This topic is notified when an a category was cleared in the category
+ * manager. The subject of the notification will be the category manager,
+ * and the data will be the name of the cleared category.
+ *
+ * @status FROZEN
+ */
+#define NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID "xpcom-category-cleared"
+
 extern "C" NS_COM nsresult
 NS_GetDebug(nsIDebug* *result);
 

xpcom/components/nsCategoryManager.cpp

@@ -53,6 +53,7 @@
 #include "nsSupportsPrimitives.h"
 #include "nsServiceManagerUtils.h"
 #include "nsIObserver.h"
+#include "nsIObserverService.h"
 #include "nsReadableUtils.h"
 #include "nsCRT.h"
 #include "nsQuickSort.h"
@@ -517,6 +518,39 @@ nsCategoryManager::get_category(const char* aName) {
   return node;
 }
 
+void
+nsCategoryManager::NotifyObservers( const char *aTopic,
+                                    const char *aCategoryName,
+                                    const char *aEntryName )
+{
+  if (mSuppressNotifications)
+    return;
+
+  nsCOMPtr<nsIObserverService> observerService
+    (do_GetService("@mozilla.org/observer-service;1"));
+  if (!observerService)
+    return;
+ 
+  if (aEntryName) {
+    nsCOMPtr<nsISupportsCString> entry
+      (do_CreateInstance (NS_SUPPORTS_CSTRING_CONTRACTID));
+    if (!entry)
+      return;
+
+    nsresult rv = entry->SetData(nsDependentCString(aEntryName));
+    if (NS_FAILED(rv))
+      return;
+
+    observerService->NotifyObservers
+                       (entry, aTopic,
+                        NS_ConvertUTF8toUTF16(aCategoryName).get());
+  } else {
+    observerService->NotifyObservers
+                       (this, aTopic,
+                        NS_ConvertUTF8toUTF16(aCategoryName).get());
+  }
+}
+
 NS_IMETHODIMP
 nsCategoryManager::GetCategoryEntry( const char *aCategoryName,
                                      const char *aEntryName,
@@ -568,12 +602,19 @@ nsCategoryManager::AddCategoryEntry( const char *aCategoryName,
   if (!category)
     return NS_ERROR_OUT_OF_MEMORY;
 
-  return category->AddLeaf(aEntryName,
-                           aValue,
-                           aPersist,
-                           aReplace,
-                           _retval,
-                           &mArena);
+  nsresult rv = category->AddLeaf(aEntryName,
+                                  aValue,
+                                  aPersist,
+                                  aReplace,
+                                  _retval,
+                                  &mArena);
+
+  if (NS_SUCCEEDED(rv)) {
+    NotifyObservers(NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID,
+                    aCategoryName, aEntryName);
+  }
+
+  return rv;
 }
 
 NS_IMETHODIMP
@@ -597,8 +638,15 @@ nsCategoryManager::DeleteCategoryEntry( const char *aCategoryName,
   if (!category)
     return NS_OK;
 
-  return category->DeleteLeaf(aEntryName,
-                              aDontPersist);
+  nsresult rv = category->DeleteLeaf(aEntryName,
+                                     aDontPersist);
+
+  if (NS_SUCCEEDED(rv)) {
+    NotifyObservers(NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID,
+                    aCategoryName, aEntryName);
+  }
+
+  return rv;
 }
 
 NS_IMETHODIMP
@@ -614,8 +662,11 @@ nsCategoryManager::DeleteCategory( const char *aCategoryName )
   CategoryNode* category = get_category(aCategoryName);
   PR_Unlock(mLock);
 
-  if (category)
+  if (category) {
     category->Clear();
+    NotifyObservers(NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID,
+                    aCategoryName, nsnull);
+  }
 
   return NS_OK;
 }
@@ -694,6 +745,13 @@ nsCategoryManager::WriteCategoryManagerToRegistry(PRFileDesc* fd)
   return NS_OK;
 }
 
+NS_METHOD
+nsCategoryManager::SuppressNotifications(PRBool aSuppress)
+{
+  mSuppressNotifications = aSuppress;
+  return NS_OK;
+}
+
 class nsCategoryManagerFactory : public nsIFactory
    {
      public:

xpcom/components/nsCategoryManager.h

@@ -142,6 +142,13 @@ public:
    */
   NS_METHOD WriteCategoryManagerToRegistry(PRFileDesc* fd);
 
+  /**
+   * Suppress or unsuppress notifications of category changes to the
+   * observer service. This is to be used by nsComponentManagerImpl
+   * on startup while reading the stored category list.
+   */
+  NS_METHOD SuppressNotifications(PRBool aSuppress);
+
   nsCategoryManager() { }
 private:
   friend class nsCategoryManagerFactory;
@@ -150,10 +157,14 @@ private:
   ~nsCategoryManager();
 
   CategoryNode* get_category(const char* aName);
+  void NotifyObservers(const char* aTopic,
+                       const char* aCategoryName,
+                       const char* aEntryName);
 
   PLArenaPool mArena;
   nsClassHashtable<nsDepCharHashKey, CategoryNode> mTable;
   PRLock* mLock;
+  PRBool mSuppressNotifications;
 };
 
 #endif

xpcom/components/nsComponentManager.cpp

@@ -1295,6 +1295,8 @@ nsComponentManagerImpl::ReadPersistentRegistry()
     if (ReadSectionHeader(reader, "CATEGORIES"))
         goto out;
 
+    mCategoryManager->SuppressNotifications(PR_TRUE);
+
     while (1)
     {
         if (!reader.NextLine())
@@ -1312,6 +1314,8 @@ nsComponentManagerImpl::ReadPersistentRegistry()
                                            0);
     }
 
+    mCategoryManager->SuppressNotifications(PR_FALSE);
+
     mRegistryDirty = PR_FALSE;
 out:
     if (fd)