Split TemplateHashMapImpl::Lookup into two methods

src/hashmap.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HASHMAP_H_
 #define V8_HASHMAP_H_
 
 #include "src/allocation.h"
 #include "src/base/bits.h"
 #include "src/base/logging.h"
@@ skipping 23 matching lines @@
   // HashMap entries are (key, value, hash) triplets.
   // Some clients may not need to use the value slot
   // (e.g. implementers of sets, where the key is the value).
   struct Entry {
     void* key;
     void* value;
     uint32_t hash;  // The full hash value for key
     int order;  // If you never remove entries this is the insertion order.
   };
 
-  // If an entry with matching key is found, Lookup()
-  // returns that entry. If no matching entry is found,
-  // but insert is set, a new entry is inserted with
+  // If an entry with matching key is found, returns that entry.
+  // Otherwise, NULL is returned.
+  Entry* Lookup(void* key, uint32_t hash);
+
+  // If an entry with matching key is found, returns that entry.
+  // If no matching entry is found, a new entry is inserted with
   // corresponding key, key hash, and NULL value.
-  // Otherwise, NULL is returned.
-  Entry* Lookup(void* key, uint32_t hash, bool insert,
-                AllocationPolicy allocator = AllocationPolicy());
+  Entry* LookupOrInsert(void* key, uint32_t hash,
+                        AllocationPolicy allocator = AllocationPolicy());
 
   // Removes the entry with matching key.
   // It returns the value of the deleted entry
   // or null if there is no value for such key.
   void* Remove(void* key, uint32_t hash);
 
   // Empties the hash map (occupancy() == 0).
   void Clear();
 
   // The number of (non-empty) entries in the table.
@@ skipping 41 matching lines @@
   Initialize(initial_capacity, allocator);
 }
 
 
 template<class AllocationPolicy>
 TemplateHashMapImpl<AllocationPolicy>::~TemplateHashMapImpl() {
   AllocationPolicy::Delete(map_);
 }
 
 
-template<class AllocationPolicy>
+template <class AllocationPolicy>
 typename TemplateHashMapImpl<AllocationPolicy>::Entry*
-TemplateHashMapImpl<AllocationPolicy>::Lookup(
-    void* key, uint32_t hash, bool insert, AllocationPolicy allocator) {
+TemplateHashMapImpl<AllocationPolicy>::Lookup(void* key, uint32_t hash) {
+  Entry* p = Probe(key, hash);
+  return p->key != NULL ? p : NULL;

[marja, 2015/04/10 07:59:58]

We seem to be migrating to use nullptr instead of NULL in new code, so you could
use that here.

[adamk, 2015/04/13 18:34:41]

I'd favor consistency here, if that's ok with you; NULL is used throughout the
file.

+}
+
+
+template <class AllocationPolicy>
+typename TemplateHashMapImpl<AllocationPolicy>::Entry*
+TemplateHashMapImpl<AllocationPolicy>::LookupOrInsert(
+    void* key, uint32_t hash, AllocationPolicy allocator) {
   // Find a matching entry.
   Entry* p = Probe(key, hash);
   if (p->key != NULL) {
     return p;
   }
 
-  // No entry found; insert one if necessary.
-  if (insert) {
-    p->key = key;
-    p->value = NULL;
-    p->hash = hash;
-    p->order = occupancy_;
-    occupancy_++;
+  // No entry found; insert one.
+  p->key = key;
+  p->value = NULL;
+  p->hash = hash;
+  p->order = occupancy_;
+  occupancy_++;
 
-    // Grow the map if we reached >= 80% occupancy.
-    if (occupancy_ + occupancy_/4 >= capacity_) {
-      Resize(allocator);
-      p = Probe(key, hash);
-    }
-
-    return p;
+  // Grow the map if we reached >= 80% occupancy.
+  if (occupancy_ + occupancy_ / 4 >= capacity_) {
+    Resize(allocator);
+    p = Probe(key, hash);
   }
 
-  // No entry found and none inserted.
-  return NULL;
+  return p;
 }
 
 
 template<class AllocationPolicy>
 void* TemplateHashMapImpl<AllocationPolicy>::Remove(void* key, uint32_t hash) {
   // Lookup the entry for the key to remove.
   Entry* p = Probe(key, hash);
   if (p->key == NULL) {
     // Key not found nothing to remove.
     return NULL;
@@ skipping 77 matching lines @@
   DCHECK(map_ - 1 <= p && p < end);
   for (p++; p < end; p++) {
     if (p->key != NULL) {
       return p;
     }
   }
   return NULL;
 }
 
 
-template<class AllocationPolicy>
+template <class AllocationPolicy>
 typename TemplateHashMapImpl<AllocationPolicy>::Entry*
-    TemplateHashMapImpl<AllocationPolicy>::Probe(void* key, uint32_t hash) {
+TemplateHashMapImpl<AllocationPolicy>::Probe(void* key, uint32_t hash) {
   DCHECK(key != NULL);
 
   DCHECK(base::bits::IsPowerOfTwo32(capacity_));
   Entry* p = map_ + (hash & (capacity_ - 1));
   const Entry* end = map_end();
   DCHECK(map_ <= p && p < end);
 
   DCHECK(occupancy_ < capacity_);  // Guarantees loop termination.
   while (p->key != NULL && (hash != p->hash || !match_(key, p->key))) {
     p++;
@@ skipping 24 matching lines @@
 void TemplateHashMapImpl<AllocationPolicy>::Resize(AllocationPolicy allocator) {
   Entry* map = map_;
   uint32_t n = occupancy_;
 
   // Allocate larger map.
   Initialize(capacity_ * 2, allocator);
 
   // Rehash all current entries.
   for (Entry* p = map; n > 0; p++) {
     if (p->key != NULL) {
-      Entry* entry = Lookup(p->key, p->hash, true, allocator);
+      Entry* entry = LookupOrInsert(p->key, p->hash, allocator);
       entry->value = p->value;
       entry->order = p->order;
       n--;
     }
   }
 
   // Delete old map.
   AllocationPolicy::Delete(map);
 }
 
@@ skipping 35 matching lines @@
       AllocationPolicy allocator = AllocationPolicy())
         : TemplateHashMapImpl<AllocationPolicy>(
             match,
             TemplateHashMapImpl<AllocationPolicy>::kDefaultHashMapCapacity,
             allocator) { }
 
   Iterator begin() const { return Iterator(this, this->Start()); }
   Iterator end() const { return Iterator(this, NULL); }
   Iterator find(Key* key, bool insert = false,
                 AllocationPolicy allocator = AllocationPolicy()) {
-    return Iterator(this, this->Lookup(key, key->Hash(), insert, allocator));
+    if (insert) {
+      return Iterator(this, this->LookupOrInsert(key, key->Hash(), allocator));
+    }
+    return Iterator(this, this->Lookup(key, key->Hash()));
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HASHMAP_H_