Merge pull request #224 from AI0867/wesnothd_memory_leak

Fix a memory leak in forum_user_handler
wesnoth · Jul 1, 2014 · d8aea90 · d8aea90
2 parents 34da068 + 907d348
commit d8aea90
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Showing 2 changed files with 21 additions and 6 deletions.
diff --git a/src/server/forum_user_handler.cpp b/src/server/forum_user_handler.cpp
@@ -115,7 +115,8 @@ bool fuh::user_exists(const std::string& name) {
 
 	// Make a test query for this username
 	try {
-		return mysql_fetch_row(db_query("SELECT username FROM " + db_users_table_ + " WHERE UPPER(username)=UPPER('" + name + "')"));
+		mysql_result res = db_query("SELECT username FROM " + db_users_table_ + " WHERE UPPER(username)=UPPER('" + name + "')");
+		return mysql_fetch_row(res.get());
 	} catch (error& e) {
 		ERR_UH << "Could not execute test query for user '" << name << "' :" << e.message << std::endl;
 		// If the database is down just let all usernames log in
@@ -248,7 +249,13 @@ void fuh::set_lastlogin(const std::string& user, const time_t& lastlogin) {
 	}
 }
 
-MYSQL_RES* fuh::db_query(const std::string& sql) {
+struct result_deleter {
+	void operator()(MYSQL_RES *result) {
+		mysql_free_result(result);
+	}
+};
+
+fuh::mysql_result fuh::db_query(const std::string& sql) {
 	if(mysql_query(conn, sql.c_str())) {
 		WRN_UH << "not connected to database, reconnecting..." << std::endl;
 		//Try to reconnect and execute query again
@@ -258,11 +265,12 @@ MYSQL_RES* fuh::db_query(const std::string& sql) {
 			throw error("Error querying database.");
 		}
 	}
-	return mysql_store_result(conn);
+	return mysql_result(mysql_store_result(conn), result_deleter());
 }
 
 std::string fuh::db_query_to_string(const std::string& sql) {
-	return std::string(mysql_fetch_row(db_query(sql))[0]);
+	mysql_result res = db_query(sql);
+	return std::string(mysql_fetch_row(res.get())[0]);
 }
 
 
@@ -292,7 +300,8 @@ bool fuh::extra_row_exists(const std::string& name) {
 
 	// Make a test query for this username
 	try {
-		return mysql_fetch_row(db_query("SELECT username FROM " + db_extra_table_ + " WHERE UPPER(username)=UPPER('" + name + "')"));
+		mysql_result res = db_query("SELECT username FROM " + db_extra_table_ + " WHERE UPPER(username)=UPPER('" + name + "')");
+		return mysql_fetch_row(res.get());
 	} catch (error& e) {
 		ERR_UH << "Could not execute test query for user '" << name << "' :" << e.message << std::endl;
 		return false;

diff --git a/src/server/forum_user_handler.hpp b/src/server/forum_user_handler.hpp
@@ -19,6 +19,7 @@
 
 #include <vector>
 
+#include <boost/shared_ptr.hpp>
 #include <mysql/mysql.h>
 
 // The [user_handler] section in the server configuration
@@ -93,8 +94,13 @@ class fuh : public user_handler {
 
 		std::string db_name_, db_host_, db_user_, db_password_, db_users_table_, db_extra_table_;
 
+		// std::unique_ptr would be better, as the object isn't actually shared
+		// boost::scoped_ptr cannot be returned, so we can't use that
+		// TODO C++11: switch to std::unique_ptr
+		typedef boost::shared_ptr<MYSQL_RES> mysql_result;
+
 		// Throws user_handler::error
-		MYSQL_RES* db_query(const std::string& query);
+		mysql_result db_query(const std::string& query);
 
 		// Throws user_handler::error via db_query()
 		std::string db_query_to_string(const std::string& query);