Adding V8 api to get memory statistics of spaces in V8::Heap.

include/v8.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.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
  *
  * For other documentation see http://code.google.com/apis/v8/
  */
 
 #ifndef V8_H_
 #define V8_H_
 
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <vector>

[rmcilroy, 2015/04/13 17:40:07]

We probably don't want to pull in <vector> to be a requirement of V8's public
API. Maybe just forward declare std::vector in the header, and only store a
pointer to the vector in the HeapStatistics object (so that it only needs the
forward declaration).

 
 #include "v8-version.h"
 #include "v8config.h"
 
 // We reserve the V8_* prefix for macros defined in V8 public API and
 // assume there are no name conflicts with the embedder's code.
 
 #ifdef V8_OS_WIN
 
 // Setup for Windows DLL export/import. When building the V8 DLL the
@@ skipping 4815 matching lines @@
 
 /**
  * Collection of V8 heap information.
  *
  * Instances of this class can be passed to v8::V8::HeapStatistics to
  * get heap statistics from V8.
  */
 class V8_EXPORT HeapStatistics {
  public:
   HeapStatistics();
+
+  class SpaceStatistics {
+   public:
+    SpaceStatistics(size_t size_of_objects, size_t committed_memory,

[rmcilroy, 2015/04/13 17:40:07]

Add a name field so we know what each space each SpaceStatitics represents. 

[rmcilroy, 2015/04/13 17:40:08]

nit - each arg on a newline

[ssid, 2015/04/14 16:59:16]

Done.

+                    size_t available_memory)
+        : size_of_objects_(size_of_objects),
+          committed_memory_(committed_memory),
+          available_memory_(available_memory) {}
+    size_t size_of_objects_;
+    size_t committed_memory_;
+    size_t available_memory_;

[rmcilroy, 2015/04/13 17:40:07]

I think we should make these more obvious names if they are part of the external
API. Also, let's make this consistent with the total amounts below so:
 - CommittedMemory() -> space_size
 - SizeOfObjects() -> space_used_size
 - Available() -> space_available_size

also lets add CommittedPhysicalMemory() -> physical_space_size to be consistent.

[ssid, 2015/04/14 16:59:16]

Done.

+  };
+
   size_t total_heap_size() { return total_heap_size_; }
   size_t total_heap_size_executable() { return total_heap_size_executable_; }
   size_t total_physical_size() { return total_physical_size_; }
   size_t used_heap_size() { return used_heap_size_; }
   size_t heap_size_limit() { return heap_size_limit_; }
+  std::vector<SpaceStatistics> spaces_statistics() {
+    return spaces_statistics_;
+  }
 
  private:
   size_t total_heap_size_;
   size_t total_heap_size_executable_;
   size_t total_physical_size_;
   size_t used_heap_size_;
   size_t heap_size_limit_;
+  std::vector<SpaceStatistics> spaces_statistics_;
 
   friend class V8;
   friend class Isolate;
 };
 
 
 class RetainedObjectInfo;
 
 
 /**
@@ skipping 3190 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // V8_H_