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

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 8019a4522b4bafb811263bc39bb53e516fbeb2b6..a44177807298679b5913eb3627ee661cec523fff 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -18,6 +18,7 @@
 #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"
@@ -4853,11 +4854,27 @@ typedef void (*InterruptCallback)(Isolate* isolate, void* data);
 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_;
@@ -4865,6 +4882,7 @@ class V8_EXPORT HeapStatistics {
   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;