Having the block size as a template parameter makes all the code very

verbose, and we're not likely to change it.  So this change removes
that template arg from everything except the block manager.

transaction_manager.cc

@@ -0,0 +1,152 @@
+#include "transaction_manager.h"
+
+#include <string.h>
+
+using namespace boost;
+using namespace persistent_data;
+using namespace std;
+
+//----------------------------------------------------------------
+
+transaction_manager::transaction_manager(typename block_manager<>::ptr bm,
+					 space_map::ptr sm)
+	: bm_(bm),
+	  sm_(sm)
+{
+}
+
+transaction_manager::~transaction_manager()
+{
+}
+
+transaction_manager::write_ref
+transaction_manager::begin(block_address superblock)
+{
+	write_ref wr = bm_->superblock(superblock);
+	wipe_shadow_table();
+	return wr;
+}
+
+transaction_manager::write_ref
+transaction_manager::begin(block_address superblock, validator v)
+{
+	write_ref wr = bm_->superblock(superblock, v);
+	wipe_shadow_table();
+	return wr;
+}
+
+// FIXME: these explicit try/catches are gross
+transaction_manager::write_ref
+transaction_manager::new_block()
+{
+	block_address b = sm_->new_block();
+	try {
+		add_shadow(b);
+		try {
+			return bm_->write_lock_zero(b);
+		} catch (...) {
+			remove_shadow(b);
+			throw;
+		}
+
+	} catch (...) {
+		sm_->dec(b);
+		throw;
+	}
+}
+
+transaction_manager::write_ref
+transaction_manager::new_block(validator v)
+{
+	block_address b = sm_->new_block();
+	try {
+		add_shadow(b);
+		try {
+			return bm_->write_lock_zero(b, v);
+		} catch (...) {
+			remove_shadow(b);
+			throw;
+		}
+	} catch (...) {
+		sm_->dec(b);
+		throw;
+	}
+}
+
+// FIXME: make exception safe
+pair<transaction_manager::write_ref, bool>
+transaction_manager::shadow(block_address orig)
+{
+	if (is_shadow(orig) &&
+	    !sm_->count_possibly_greater_than_one(orig))
+		return make_pair(bm_->write_lock(orig), false);
+
+	read_ref src = bm_->read_lock(orig);
+	write_ref dest = bm_->write_lock_zero(sm_->new_block());
+	::memcpy(dest.data(), src.data(), MD_BLOCK_SIZE);
+
+	ref_t count = sm_->get_count(orig);
+	if (count == 0)
+		throw runtime_error("shadowing free block");
+	sm_->dec(orig);
+	add_shadow(dest.get_location());
+	return make_pair(dest, count > 1);
+}
+
+// FIXME: duplicate code
+pair<transaction_manager::write_ref, bool>
+transaction_manager::shadow(block_address orig, validator v)
+{
+	if (is_shadow(orig) &&
+	    sm_->count_possibly_greater_than_one(orig))
+		return make_pair(bm_->write_lock(orig), false);
+
+	read_ref src = bm_->read_lock(orig, v);
+	write_ref dest = bm_->write_lock_zero(sm_->new_block(), v);
+	::memcpy(dest.data(), src.data(), MD_BLOCK_SIZE);
+
+	ref_t count = sm_->get_count(orig);
+	if (count == 0)
+		throw runtime_error("shadowing free block");
+	sm_->dec(orig);
+	add_shadow(dest.get_location());
+	return make_pair(dest, count > 1);
+}
+
+transaction_manager::read_ref
+transaction_manager::read_lock(block_address b)
+{
+	return bm_->read_lock(b);
+}
+
+transaction_manager::read_ref
+transaction_manager::read_lock(block_address b, validator v)
+{
+	return bm_->read_lock(b, v);
+}
+
+void
+transaction_manager::add_shadow(block_address b)
+{
+	shadows_.insert(b);
+}
+
+void
+transaction_manager::remove_shadow(block_address b)
+{
+	shadows_.erase(b);
+}
+
+bool
+transaction_manager::is_shadow(block_address b) const
+{
+	return shadows_.count(b) > 0;
+}
+
+void
+transaction_manager::wipe_shadow_table()
+{
+	shadows_.clear();
+}
+
+//----------------------------------------------------------------