386376 get services lazily in order to avoid recursive getService calls

r=bsmedberg

netwerk/base/src/nsIOService.h

@@ -102,7 +102,7 @@ public:
                                PRUint32 flags);
 
     // Gets the array of registered content sniffers
-    const nsCOMArray<nsIContentSniffer>& GetContentSniffers() const {
+    const nsCOMArray<nsIContentSniffer>& GetContentSniffers() {
       return mContentSniffers.GetEntries();
     }
 

xpcom/glue/nsCategoryCache.h

@@ -91,7 +91,13 @@ class nsCategoryCache : protected nsCategoryListener {
     explicit nsCategoryCache(const char* aCategory);
     ~nsCategoryCache() { if (mObserver) mObserver->ListenerDied(); }
 
-    const nsCOMArray<T>& GetEntries() const { return mEntries; }
+    const nsCOMArray<T>& GetEntries() {
+      // Lazy initialization, so that services in this category can't
+      // cause reentrant getService (bug 386376)
+      if (!mObserver)
+        mObserver = new nsCategoryObserver(mCategoryName.get(), this);
+      return mEntries;
+    }
   protected:
     virtual void EntryAdded(const nsCString& aValue);
     virtual void EntryRemoved(const nsCString& aValue);
@@ -102,6 +108,7 @@ class nsCategoryCache : protected nsCategoryListener {
     // Not to be implemented
     nsCategoryCache(const nsCategoryCache<T>&);
 
+    nsCString mCategoryName;
     nsCOMArray<T> mEntries;
     nsRefPtr<nsCategoryObserver> mObserver;
 };
@@ -111,8 +118,8 @@ class nsCategoryCache : protected nsCategoryListener {
 
 template<class T>
 nsCategoryCache<T>::nsCategoryCache(const char* aCategory)
+: mCategoryName(aCategory)
 {
-  mObserver = new nsCategoryObserver(aCategory, this);
 }
 
 template<class T>