readonly support

Db.h

@@ -64,6 +64,7 @@ struct DbDirEntry {
 
 struct DbIntf {
 	DbStats stats;
+	virtual Return setReadOnly(bool ro) { return "Db::setReadOnly: not implemented"; }
 	virtual Return init() = 0;
 	virtual Return push(/*out*/ DbEntryId& id, const DbEntry& entry) = 0;
 	virtual Return get(/*out*/ DbEntry& entry, const DbEntryId& id) = 0;

DbKyotoBackend.cpp

@@ -13,10 +13,11 @@ using namespace std;
 using namespace kyotocabinet;
 
 DbKyotoBackend::~DbKyotoBackend() {
+	db.close();
 }
 
 Return DbKyotoBackend::init() {
-	if(!db.open(filename, PolyDB::OWRITER | PolyDB::OCREATE))
+	if(!db.open(filename, readonly ? PolyDB::OREADER : (PolyDB::OWRITER | PolyDB::OCREATE)))
 		return std::string() + "failed to open KyotoCabinet DB: " + db.error().name();
 	return true;
 }

DbKyotoBackend.h

@@ -12,9 +12,11 @@
 struct DbKyotoBackend : DbIntf {
 	kyotocabinet::PolyDB db;
 	std::string filename;
+	bool readonly;
 
-	DbKyotoBackend(const std::string& dbfilename = "db.kch") : filename(dbfilename) {}
+	DbKyotoBackend(const std::string& dbfilename = "db.kch", bool ro = false) : filename(dbfilename), readonly(ro) {}
 	~DbKyotoBackend();
+	Return setReadOnly(bool ro) { readonly = ro; return true; }
 	Return init();
 	Return push(/*out*/ DbEntryId& id, const DbEntry& entry);
 	Return get(/*out*/ DbEntry& entry, const DbEntryId& id);

db-list-dir.cpp

@@ -51,6 +51,7 @@ static Return listDir(const std::string& path) {
 static Return _main() {
 	DbDefBackend dbInst;
 	db = &dbInst;
+	db->setReadOnly(true);
 	ASSERT( db->init() );
 	ASSERT( listDir("") );
 	return true;