From ed65ebdede34bcfa744df1b914cd723ba7af27a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pawe=C5=82=20Bylica?= <chfast@gmail.com>
Date: Fri, 12 Jun 2015 13:27:26 +0200
Subject: [PATCH] Remove debug logs and add comments.

---
 libethereum/ExtVM.cpp | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/libethereum/ExtVM.cpp b/libethereum/ExtVM.cpp
index b32d308f2..305462511 100644
--- a/libethereum/ExtVM.cpp
+++ b/libethereum/ExtVM.cpp
@@ -29,28 +29,35 @@ using namespace dev::eth;
 
 namespace
 {
+
 static unsigned const c_depthLimit = 1024;
+
+/// Upper bound of stack space needed by single CALL/CREATE execution. Set experimentally.
 static size_t const c_singleExecutionStackSize = 12 * 1024;
+
+/// Standard OSX thread stack limit. Should be reasonable for other platforms too.
 static size_t const c_defaultStackSize = 512 * 1024;
+
+/// On what depth execution should be offloaded to additional separated stack space.
 static unsigned const c_offloadPoint = c_defaultStackSize / c_singleExecutionStackSize;
 
 void goOnOffloadedStack(Executive& _e, OnOpFunc const& _onOp)
 {
-	cnote << "CALL OFFLOADING: offloading point " << c_offloadPoint;
+	// Set new stack size enouth to handle the rest of the calls up to the limit.
 	boost::thread::attributes attrs;
 	attrs.set_stack_size((c_depthLimit - c_offloadPoint) * c_singleExecutionStackSize);
 
+	// Create new thread with big stack and join immediately.
+	// TODO: It is possible to switch the implementation to Boost.Context or similar when the API is stable.
 	std::exception_ptr exception;
 	boost::thread{attrs, [&]{
-		cnote << "OFFLOADING thread";
 		try
 		{
 			_e.go(_onOp);
 		}
 		catch (...)
 		{
-			cnote << "!!!!!!!!!!! exception in offloading!!!!!!!!!!!!";
-			exception = std::current_exception();
+			exception = std::current_exception(); // Catch all exceptions to be rethrown in parent thread.
 		}
 	}}.join();
 	if (exception)
@@ -59,6 +66,10 @@ void goOnOffloadedStack(Executive& _e, OnOpFunc const& _onOp)
 
 void go(unsigned _depth, Executive& _e, OnOpFunc const& _onOp)
 {
+	// If in the offloading point we need to switch to additional separated stack space.
+	// Current stack is too small to handle more CALL/CREATE executions.
+	// It needs to be done only once as newly allocated stack space it enough to handle 
+	// the rest of the calls up to the depth limit (c_depthLimit).
 	if (_depth == c_offloadPoint)
 		goOnOffloadedStack(_e, _onOp);
 	else