Issue 6279 - Make HashContainer movable and optimize resizing by moving entries.

compiled/Map.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 144 matching lines @@
       {
         entry_type& entry = oldBuckets[i];
         if (!entry.is_invalid() && !entry.is_deleted())
         {
           *find_bucket(entry.first) = std::move(entry);
           mEntryCount++;
         }
       }
     }
 
-    entry_type* _assign(entry_type* existing, const entry_type& entry)

[sergei, 2018/01/24 18:37:12]

We normally don't use underscores at the beginning of the names, what about
something like `incrementSize` (something better is very welcomed)? IMO it
should reflect that the function increases mEntryCount if necessary and adjusts
the capacity in accordance with the LOAD_FACTOR.

[hub, 2018/01/24 19:32:01]

I'll call it "prepare_bucket" as we use it to ensure we have a bucket to assign
the entry to. Also I'll change the argument to just take the key instead of the
actual entry. 

+    // Prepare the bucket for assigning entry at key.
+    entry_type* prepare_bucket(entry_type* existing, key_type_cref key)
     {
       if (existing->is_invalid())
       {
         if (mEntryCount + 1 >= mBucketCount * LOAD_FACTOR)
         {
           resize(mBucketCount << 1);
-          existing = find_bucket(entry.first);
+          existing = find_bucket(key);
         }
         mEntryCount++;
 #if defined(DEBUG)
         mInsertCounter++;
 #endif
       }
       return existing;
     }
 
     entry_type* assign(entry_type* existing, const entry_type& entry)
     {
-      existing = _assign(existing, entry);
+      existing = prepare_bucket(existing, entry.first);
       *existing = entry;
       return existing;
     }
 
     entry_type* assign(entry_type* existing, entry_type&& entry)
     {
-      existing = _assign(existing, entry);
+      existing = prepare_bucket(existing, entry.first);
       *existing = std::move(entry);
       return existing;
     }
 
     void allocate()
     {
       mBuckets.reset(new entry_type[mBucketCount]);
       // Working around https://github.com/waywardmonkeys/emscripten-trace-collector/issues/2 here
       annotate_address(reinterpret_cast<size_type*>(mBuckets.get()) - 1, "Hash table buffer");
     }
@@ skipping 127 matching lines @@
   const_reference find(key_type_cref key) const
   {
     return super::find(key);
   }
 
   reference find(key_type_cref key)
   {
     return reference(this, key, super::find_bucket(key));
   }
 };