add sm_decrementer

Makefile

@@ -13,6 +13,7 @@ SOURCE=\
 	metadata_dumper.cc \
 	metadata_disk_structures.cc \
 	restore_emitter.cc \
+	space_map.cc \
 	space_map_disk.cc \
 	thin_pool.cc \
 	transaction_manager.cc \
@@ -25,7 +26,7 @@ PROGRAM_SOURCE=\
 
 OBJECTS=$(subst .cc,.o,$(SOURCE))
 TOP_DIR:=$(PWD)
-CPPFLAGS=-Wall -g -I$(TOP_DIR) -O8
+CPPFLAGS=-Wall -g -I$(TOP_DIR)
 #CPPFLAGS=-Wall -std=c++0x -g -I$(TOP_DIR)
 LIBS=-lstdc++ -lboost_program_options -lexpat
 

space_map.cc

@@ -0,0 +1,23 @@
+#include "space_map.h"
+
+using namespace persistent_data;
+
+//----------------------------------------------------------------
+
+sm_decrementer::sm_decrementer(space_map::ptr sm, block_address b)
+	: sm_(sm),
+	  b_(b),
+	  released_(false) {
+}
+
+sm_decrementer::~sm_decrementer() {
+	if (!released_)
+		sm_->dec(b_);
+}
+
+void
+sm_decrementer::dont_bother() {
+	released_ = true;
+}
+
+//----------------------------------------------------------------

space_map.h

@@ -48,6 +48,53 @@ namespace persistent_data {
 		virtual size_t root_size() = 0;
 		virtual void copy_root(void *dest, size_t len) = 0;
 	};
+
+	class sm_adjust {
+	public:
+		sm_adjust(space_map::ptr sm, block_address b, int delta)
+			: sm_(sm),
+			  b_(b),
+			  delta_(delta) {
+
+			adjust_count(delta_);
+		}
+
+		~sm_adjust() {
+			adjust_count(-delta_);
+		}
+
+		void release() {
+			delta_ = 0;
+		}
+
+	private:
+		void adjust_count(int delta) {
+			if (delta == 1)
+				sm_->inc(b_);
+
+			else if (delta == -1)
+				sm_->dec(b_);
+
+			else
+				sm_->set_count(b_, sm_->get_count(b_) + delta);
+		}
+
+		space_map::ptr sm_;
+		block_address b_;
+		int delta_;
+	};
+
+	class sm_decrementer {
+	public:
+		sm_decrementer(space_map::ptr sm, block_address b);
+		~sm_decrementer();
+		void dont_bother();
+
+	private:
+		space_map::ptr sm_;
+		block_address b_;
+		bool released_;
+	};
 }
 
 //----------------------------------------------------------------