Bug 1692403 - Don't shrink hashtable in EntryHandle destructor. r=xpcom-reviewers,nika

Differential Revision: https://phabricator.services.mozilla.com/D108171

Author: sigiesec

xpcom/ds/PLDHashTable.cpp

@@ -697,20 +697,15 @@ PLDHashTable::EntryHandle::EntryHandle(EntryHandle&& aOther) noexcept
       mKeyHash(aOther.mKeyHash),
       mSlot(aOther.mSlot) {}
 
+#ifdef MOZ_HASH_TABLE_CHECKS_ENABLED
 PLDHashTable::EntryHandle::~EntryHandle() {
   if (!mTable) {
     return;
   }
 
-  // If our slot is empty when this `EntryHandle` is destroyed, we may want to
-  // resize our table, as we just removed an entry.
-  if (!HasEntry()) {
-    mTable->ShrinkIfAppropriate();
-  }
-#ifdef MOZ_HASH_TABLE_CHECKS_ENABLED
   mTable->mChecker.EndWriteOp();
-#endif
 }
+#endif
 
 void PLDHashTable::EntryHandle::Remove() {
   MOZ_ASSERT(HasEntry());

xpcom/ds/PLDHashTable.h

@@ -532,7 +532,9 @@ class PLDHashTable {
   class EntryHandle {
    public:
     EntryHandle(EntryHandle&& aOther) noexcept;
+#ifdef MOZ_HASH_TABLE_CHECKS_ENABLED
     ~EntryHandle();
+#endif
 
     EntryHandle(const EntryHandle&) = delete;
     EntryHandle& operator=(const EntryHandle&) = delete;
@@ -568,8 +570,19 @@ class PLDHashTable {
       return Entry();
     }
 
+    /** Removes the entry. Note that the table won't shrink on destruction of
+     * the EntryHandle.
+     *
+     * \pre HasEntry()
+     * \post !HasEntry()
+     */
     void Remove();
 
+    /** Removes the entry, if it exists. Note that the table won't shrink on
+     * destruction of the EntryHandle.
+     *
+     * \post !HasEntry()
+     */
     void OrRemove();
 
    private: