<rdar://problem/12523238> Commit 2 of 3

Adding the new has_children (or MightHaveChildren() in C++) for the existing synthetic children providers
In a few cases, the new call is going to be much more efficient than the previous num_children > 0 check
When the optimization was marginal (e.g. std::vector<>), the choice was to use num_children in order to keep
implementation details in one function instead of duplicating code

Next step is to provide test cases

llvm-svn: 166506

1 files changed, 27 insertions, 0 deletions

diff --git a/lldb/examples/synthetic/gnu_libstdcpp.py b/lldb/examples/synthetic/gnu_libstdcpp.py
index c08a42c6063..0d124d75865 100644
--- a/lldb/examples/synthetic/gnu_libstdcpp.py
+++ b/lldb/examples/synthetic/gnu_libstdcpp.py
@@ -132,6 +132,27 @@ class StdListSynthProvider:
 		except:
 			pass
 
+	def has_children(self):
+		logger = lldb.formatters.Logger.Logger()
+		if self.count == None:
+			self.update ()
+			try:
+				next_val = self.next.GetValueAsUnsigned(0)
+				prev_val = self.prev.GetValueAsUnsigned(0)
+				if next_val == 0 or prev_val == 0:
+					return False
+				if next_val == self.node_address:
+					return False
+				# skip all the advanced logic to detect the exact count of children
+				# in the interest of speed from this point on, we MIGHT have children
+				# our loop detection logic will still make nothing show up :)
+				return True
+			except:
+				return False
+		if self.count == 0:
+			return False
+		return True
+
 class StdVectorSynthProvider:
 
 	def __init__(self, valobj, dict):
@@ -225,6 +246,10 @@ class StdVectorSynthProvider:
 				self.count = 0
 		except:
 			pass
+			
+
+	def has_children(self):
+		return self.num_children() > 0
 
 
 class StdMapSynthProvider:
@@ -408,6 +433,8 @@ class StdMapSynthProvider:
 				x = y;
 			return x;
 
+	def has_children(self):
+		return self.num_children() > 0
 
 _map_capping_size = 255
 _list_capping_size = 255