Fix constness and references in Database class

Signed-off-by: Tim Serong <[email protected]>

src/sqlite.cc

@@ -14,25 +14,25 @@
 #include <filesystem>
 #include <iostream>
 
-Database::Database(std::filesystem::path dbpath) {
-  db = dbpath;
-
+Database::Database(const std::filesystem::path& _db) : db(_db) {
   int rc = sqlite3_open(db.string().c_str(), &handle);
   if (rc != SQLITE_OK) {
     std::cout << "failed to open db" << std::endl;
     sqlite3_close(handle);
+    // FIXME: throw exception
   }
 }
 
 Database::~Database() {
   sqlite3_close(handle);
 }
 
-int Database::prepare(std::string query, sqlite3_stmt** stm) {
+int Database::prepare(const std::string& query, sqlite3_stmt** stm) const {
   int rc = 0;
   const char* unused = 0;
   rc = sqlite3_prepare(handle, query.c_str(), query.length(), stm, &unused);
   if (rc != SQLITE_OK) {
+    // FIXME: either throw an exception or log to stderr
     std::cout << "error while prepare: " << rc << std::endl;
     std::cout << query << std::endl;
   }
@@ -44,7 +44,9 @@ int Database::prepare(std::string query, sqlite3_stmt** stm) {
  *
  *   SELECT COUNT(*) FROM table WHERE condition ;
  */
-int Database::count_in_table(std::string table, std::string condition) {
+int Database::count_in_table(
+    const std::string& table, const std::string& condition
+) const {
   std::string query =
       "SELECT COUNT(*) FROM " + table + " WHERE " + condition + ";";
   int count = 0;
@@ -53,6 +55,7 @@ int Database::count_in_table(std::string table, std::string condition) {
   const char* unused = 0;
   rc = sqlite3_prepare(handle, query.c_str(), query.length(), &stm, &unused);
   if (rc != SQLITE_OK) {
+    // FIXME: either throw an exception or log to stderr
     std::cout << "error while prepare: " << rc << std::endl;
     std::cout << query << std::endl;
     return 0;
@@ -71,8 +74,8 @@ int Database::count_in_table(std::string table, std::string condition) {
  *   SELECT column FROM table WHERE column IS NOT NULL ;
  */
 std::vector<std::string> Database::select_from_table(
-    std::string table, std::string column
-) {
+    const std::string& table, const std::string& column
+) const {
   std::string query = "SELECT " + column + " FROM " + table + " WHERE " +
                       column + " IS NOT NULL;";
   int rc = 0;
@@ -81,6 +84,7 @@ std::vector<std::string> Database::select_from_table(
   std::vector<std::string> result;
   rc = sqlite3_prepare(handle, query.c_str(), query.length(), &stm, &unused);
   if (rc != SQLITE_OK) {
+    // FIXME: either throw an exception or log to stderr
     std::cout << "error while prepare: " << rc << std::endl;
     std::cout << query << std::endl;
     return result;

src/sqlite.h

@@ -22,17 +22,20 @@
 
 class Database {
  private:
-  std::filesystem::path db;
+  const std::filesystem::path& db;
 
  public:
   sqlite3* handle;
-  Database(std::filesystem::path);
+  Database(const std::filesystem::path& _db);
   ~Database();
 
-  int prepare(std::string, sqlite3_stmt**);
+  int prepare(const std::string& query, sqlite3_stmt** stm) const;
 
-  int count_in_table(std::string, std::string);
-  std::vector<std::string> select_from_table(std::string, std::string);
+  int count_in_table(const std::string& table, const std::string& condition)
+      const;
+  std::vector<std::string> select_from_table(
+      const std::string& table, const std::string& column
+  ) const;
 };
 
 #endif  // FSCK_SFS_SRC_SQLITE_H__