Parameterize CallbackStack over initial block size.

third_party/WebKit/Source/platform/heap/CallbackStack.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/heap/CallbackStack.h"
 #include "wtf/PageAllocator.h"
 
 namespace blink {
 
-CallbackStack::Block::Block(Block* next)
+CallbackStack::Block::Block(Block* next, size_t blockSize)
+    : m_blockSize(blockSize)
 {
-    static_assert((blockSize * sizeof(Item)) % WTF::kPageAllocationGranularity == 0, "CallbackStack::blockSize * sizeof(Item) must be a multiple of WTF::kPageAllocationGranularity");
-    m_buffer = static_cast<Item*>(WTF::allocPages(nullptr, blockSize * sizeof(Item), WTF::kPageAllocationGranularity, WTF::PageAccessible));
+    // Allocated block size must be a multiple of WTF::kPageAllocationGranularity.
+    ASSERT((m_blockSize * sizeof(Item)) % WTF::kPageAllocationGranularity == 0);
+    m_buffer = static_cast<Item*>(WTF::allocPages(nullptr, m_blockSize * sizeof(Item), WTF::kPageAllocationGranularity, WTF::PageAccessible));
     RELEASE_ASSERT(m_buffer);
 
 #if ENABLE(ASSERT)
     clear();
 #endif
 
-    m_limit = &(m_buffer[blockSize]);
+    m_limit = &(m_buffer[m_blockSize]);
     m_current = &(m_buffer[0]);
     m_next = next;
 }
 
 CallbackStack::Block::~Block()
 {
-    WTF::freePages(m_buffer, blockSize * sizeof(Item));
+    WTF::freePages(m_buffer, m_blockSize * sizeof(Item));
     m_buffer = nullptr;
     m_limit = nullptr;
     m_current = nullptr;
     m_next = nullptr;
 }
 
 #if ENABLE(ASSERT)
 void CallbackStack::Block::clear()
 {
-    for (size_t i = 0; i < blockSize; i++)
+    for (size_t i = 0; i < m_blockSize; i++)
         m_buffer[i] = Item(0, 0);
 }
 #endif
 
 void CallbackStack::Block::decommit()
 {
 #if ENABLE(ASSERT)
     clear();
 #endif
-    WTF::discardSystemPages(m_buffer, blockSize * sizeof(Item));
+    WTF::discardSystemPages(m_buffer, m_blockSize * sizeof(Item));
 
     m_current = &m_buffer[0];
     m_next = nullptr;
 }
 
 void CallbackStack::Block::invokeEphemeronCallbacks(Visitor* visitor)
 {
     // This loop can tolerate entries being added by the callbacks after
     // iteration starts.
     for (unsigned i = 0; m_buffer + i < m_current; i++) {
         Item& item = m_buffer[i];
         item.call(visitor);
     }
 }
 
 #if ENABLE(ASSERT)
 bool CallbackStack::Block::hasCallbackForObject(const void* object)
 {
     for (unsigned i = 0; m_buffer + i < m_current; i++) {
         Item* item = &m_buffer[i];
         if (item->object() == object)
             return true;
     }
     return false;
 }
 #endif
 
-CallbackStack::CallbackStack()
-    : m_first(new Block(0))
+CallbackStack::CallbackStack(size_t blockSize)
+    : m_first(new Block(nullptr, blockSize))
     , m_last(m_first)
 {
 }
 
 CallbackStack::~CallbackStack()
 {
     RELEASE_ASSERT(isEmpty());
     delete m_first;
     m_first = nullptr;
     m_last = nullptr;
@@ skipping 11 matching lines @@
 }
 
 bool CallbackStack::isEmpty() const
 {
     return hasJustOneBlock() && m_first->isEmptyBlock();
 }
 
 CallbackStack::Item* CallbackStack::allocateEntrySlow()
 {
     ASSERT(!m_first->allocateEntry());
-    m_first = new Block(m_first);
+    m_first = new Block(m_first, m_first->blockSize());
     return m_first->allocateEntry();
 }
 
 CallbackStack::Item* CallbackStack::popSlow()
 {
     ASSERT(m_first->isEmptyBlock());
 
     for (;;) {
         Block* next = m_first->next();
         if (!next) {
@@ skipping 25 matching lines @@
         from = m_first;
         invokeOldestCallbacks(from, upto, visitor);
     }
 }
 
 void CallbackStack::invokeOldestCallbacks(Block* from, Block* upto, Visitor* visitor)
 {
     if (from == upto)
         return;
     ASSERT(from);
-    // Recurse first (blockSize at a time) so we get to the newly added entries last.
+    // Recurse first so we get to the newly added entries last.
     invokeOldestCallbacks(from->next(), upto, visitor);
     from->invokeEphemeronCallbacks(visitor);
 }
 
 bool CallbackStack::hasJustOneBlock() const
 {
     return !m_first->next();
 }
 
 #if ENABLE(ASSERT)
 bool CallbackStack::hasCallbackForObject(const void* object)
 {
     for (Block* current = m_first; current; current = current->next()) {
         if (current->hasCallbackForObject(object))
             return true;
     }
     return false;
 }
 #endif
 
 } // namespace blink