Minor fixes to Native Heap Panel view

1. Fixes the child count in the library view.
2. The diff view used to show stack traces where new allocations
were made. But the amount of memory allocated was the cumulative
sum of all allocations made at that stack trace, rather than just
the amount allocated between the current and previous snapshots.
We detect that situation and only show the newly allocated memory.

Change-Id: I6edabf38b0c0758221983edf15e0d0b76154b962

2 files changed, 24 insertions, 0 deletions

diff --git a/ddms/ddmuilib/src/main/java/com/android/ddmuilib/heap/NativeHeapDiffSnapshot.java b/ddms/ddmuilib/src/main/java/com/android/ddmuilib/heap/NativeHeapDiffSnapshot.java
index 9eb6ddf..783e5e4 100644
--- a/ddms/ddmuilib/src/main/java/com/android/ddmuilib/heap/NativeHeapDiffSnapshot.java
+++ b/ddms/ddmuilib/src/main/java/com/android/ddmuilib/heap/NativeHeapDiffSnapshot.java
@@ -46,7 +46,28 @@ public class NativeHeapDiffSnapshot extends NativeHeapSnapshot {
             NativeHeapSnapshot oldSnapshot) {
         Set<NativeAllocationInfo> allocations =
                 new HashSet<NativeAllocationInfo>(newSnapshot.getAllocations());
+
+        // compute new allocations
         allocations.removeAll(oldSnapshot.getAllocations());
+
+        // Account for allocations with the same stack trace that were
+        // present in the older set of allocations.
+        // e.g. A particular stack trace might have had 3 allocations in snapshot 1,
+        // and 2 more in snapshot 2. We only want to show the new allocations (just the 2 from
+        // snapshot 2). However, the way the allocations are stored, in snapshot 2, we'll see
+        // 5 allocations at the stack trace. We need to subtract out the 3 from the first allocation
+        Set<NativeAllocationInfo> onlyInPrevious =
+                new HashSet<NativeAllocationInfo>(oldSnapshot.getAllocations());
+        onlyInPrevious.removeAll(newSnapshot.getAllocations());
+        for (NativeAllocationInfo allocation : allocations) {
+            for (NativeAllocationInfo old : onlyInPrevious) {
+                if (allocation.stackEquals(old)) {
+                    allocation.subtract(old);
+                    break;
+                }
+            }
+        }
+
         return new ArrayList<NativeAllocationInfo>(allocations);
     }
 
diff --git a/ddms/ddmuilib/src/main/java/com/android/ddmuilib/heap/NativeHeapProviderByLibrary.java b/ddms/ddmuilib/src/main/java/com/android/ddmuilib/heap/NativeHeapProviderByLibrary.java
index b786bfa..40b5421 100644
--- a/ddms/ddmuilib/src/main/java/com/android/ddmuilib/heap/NativeHeapProviderByLibrary.java
+++ b/ddms/ddmuilib/src/main/java/com/android/ddmuilib/heap/NativeHeapProviderByLibrary.java
@@ -56,6 +56,9 @@ public class NativeHeapProviderByLibrary implements ILazyTreeContentProvider {
         if (element instanceof NativeHeapSnapshot) {
             NativeHeapSnapshot snapshot = (NativeHeapSnapshot) element;
             childCount = getLibraryAllocations(snapshot).size();
+        } else if (element instanceof NativeLibraryAllocationInfo) {
+            NativeLibraryAllocationInfo info = (NativeLibraryAllocationInfo) element;
+            childCount = info.getAllocations().size();
         }
 
         mViewer.setChildCount(element, childCount);