2 files changed, 53 insertions, 11 deletions

diff --git a/src/crepe/facade/DB.cpp b/src/crepe/facade/DB.cpp
index bd2f089..c885560 100644
--- a/src/crepe/facade/DB.cpp
+++ b/src/crepe/facade/DB.cpp
@@ -1,6 +1,7 @@
 #include <cstring>
 
 #include "util/log.h"
+#include "Exception.h"
 
 #include "DB.h"
 
@@ -14,24 +15,22 @@ DB::DB(const string & path) {
 	// init database struct
 	libdb::DB * db;
 	if ((ret = libdb::db_create(&db, NULL, 0)) != 0)
-		throw nullptr; // TODO: exception
+		throw Exception("db_create: %s", libdb::db_strerror(ret));
 	this->db = { db, [] (libdb::DB * db) { db->close(db, 0); } };
 
 	// load or create database file
-	if ((ret = this->db->open(this->db.get(), NULL, path.c_str(), NULL, libdb::DB_BTREE, DB_CREATE, 0)) != 0) {
-		throw nullptr;
-	}
+	if ((ret = this->db->open(this->db.get(), NULL, path.c_str(), NULL, libdb::DB_BTREE, DB_CREATE, 0)) != 0)
+		throw Exception("db->open: %s", libdb::db_strerror(ret));
 
 	// create cursor
 	libdb::DBC * cursor;
-	if ((ret = this->db->cursor(this->db.get(), NULL, &cursor, 0)) != 0) {
-		throw nullptr;
-	}
+	if ((ret = this->db->cursor(this->db.get(), NULL, &cursor, 0)) != 0)
+		throw Exception("db->cursor: %s", libdb::db_strerror(ret));
 	this->cursor = { cursor, [] (libdb::DBC * cursor) { cursor->close(cursor); } };
 }
 
 
-libdb::DBT DB::to_thing(const string & thing) const {
+libdb::DBT DB::to_thing(const string & thing) const noexcept {
 	libdb::DBT thang;
 	memset(&thang, 0, sizeof(libdb::DBT));
 	thang.data = (void *) thing.data();
@@ -45,7 +44,8 @@ string DB::get(const string & key) {
 	memset(&db_val, 0, sizeof(libdb::DBT));
 
 	int ret = this->cursor->get(this->cursor.get(), &db_key, &db_val, DB_FIRST);
-	if (ret != 0) throw nullptr; // TODO: proper exception
+	if (ret != 0)
+		throw Exception("cursor->get: %s", libdb::db_strerror(ret));
 	return { static_cast<char *>(db_val.data), db_val.size };
 }
 
@@ -53,7 +53,8 @@ void DB::set(const string & key, const string & value) {
 	libdb::DBT db_key = this->to_thing(key);
 	libdb::DBT db_val = this->to_thing(value);
 	int ret = this->db->put(this->db.get(), NULL, &db_key, &db_val, 0);
-	if (ret != 0) throw nullptr; // TODO: proper exception
+	if (ret != 0)
+		throw Exception("cursor->get: %s", libdb::db_strerror(ret));
 }
 
 bool DB::has(const std::string & key) noexcept {
diff --git a/src/crepe/facade/DB.h b/src/crepe/facade/DB.h
index 06442ad..b62a974 100644
--- a/src/crepe/facade/DB.h
+++ b/src/crepe/facade/DB.h
@@ -12,22 +12,63 @@ extern "C" {
 
 namespace crepe {
 
+/**
+ * \brief Berkeley DB facade
+ *
+ * Berkeley DB is a simple key-value database that stores arbitrary data as
+ * both key and value. This facade uses STL strings as keys/values.
+ */
 class DB {
 public:
+	/**
+	 * \param path  The path of the database (created if nonexistant)
+	 */
 	DB(const std::string & path);
 	virtual ~DB() = default;
 
 public:
+	/**
+	 * \brief Get a value from the database, or throw an exception
+	 *
+	 * \param key  The value key
+	 *
+	 * \return The value
+	 *
+	 * \throws Exception if value is not found in DB or other error occurs
+	 */
 	std::string get(const std::string & key);
+	/**
+	 * \brief Set (create or overwrite) a value in the database
+	 *
+	 * \param key  The value key
+	 * \param value  The value to store
+	 *
+	 * \throws Exception if an error occurs
+	 */
 	void set(const std::string & key, const std::string & value);
+	/**
+	 * \brief Check if a key exists in the database
+	 *
+	 * \param key  The value key
+	 *
+	 * \returns True if the key exists, or false if it does not
+	 */
 	bool has(const std::string & key) noexcept;
 
 private:
+	//! RAII wrapper around \c DB struct
 	std::unique_ptr<libdb::DB, std::function<void(libdb::DB *)>> db;
+	//! RAII wrapper around \c DBC struct
 	std::unique_ptr<libdb::DBC, std::function<void(libdb::DBC *)>> cursor;
 
 private:
-	libdb::DBT to_thing(const std::string & thing) const;
+	/**
+	 * \brief Convert an STL string to DBT (data base thang)
+	 *
+	 * \param thing  Input data
+	 * \return \c DBT with the same data as input \c thing
+	 */
+	libdb::DBT to_thing(const std::string & thing) const noexcept;
 };
 
 }