Bug#33559796: Single-argument constructors should be explicit (patch #1)

This reduces the number of issues of type "Single - argument constructor
may inadvertently be used as a type conversion constructor"
as reported by Flint++ tool.
Some of the reported issues were not addressed:
 - lines explicitly marked with NOLINT (like plugin/x/src/prepare_param_handler.h)
 - false positives (tool reports alignas() calls as constructors)
 - issues where objects were intended to be used with type conversion
 - constructors with "const std::string &" param, to accept literal strings as well

Change-Id: I7eb6fabea7137fc7e81143f06ec7636b22f6ea97

client/base/debug_options.h

@@ -47,7 +47,7 @@ class Debug_options : public Abstract_options_provider {
     Constructs new debug options provider.
     @param program Pointer to main program class.
    */
-  Debug_options(Abstract_program *program);
+  explicit Debug_options(Abstract_program *program);
   /**
     Creates all options that will be provided.
     Implementation of Abstract_options_provider virtual method.

client/base/help_options.h

@@ -46,7 +46,7 @@ class Help_options : public Abstract_options_provider {
     @param program Pointer to main program class, used to collect list of all
       options available in program.
    */
-  Help_options(Base::Abstract_program *program);
+  explicit Help_options(Base::Abstract_program *program);
   /**
     Creates all options that will be provided.
     Implementation of Abstract_options_provider virtual method.

client/base/mysql_connection_options.h

@@ -78,7 +78,7 @@ class Mysql_connection_options : public Composite_options_provider,
     function from multiple threads simultaneously is not thread safe.
     @param program Pointer to main program class.
    */
-  Mysql_connection_options(Abstract_program *program);
+  explicit Mysql_connection_options(Abstract_program *program);
 
   /**
     Creates all options that will be provided.

client/base/mysql_query_runner.h

@@ -52,7 +52,7 @@ class Mysql_query_runner {
   /**
     Standard constructor based on MySQL connection.
    */
-  Mysql_query_runner(MYSQL *connection);
+  explicit Mysql_query_runner(MYSQL *connection);
   /**
     Copy constructor.
    */
@@ -200,7 +200,7 @@ class Mysql_query_runner {
 
   class Store_result_helper {
    public:
-    Store_result_helper(std::vector<const Row *> *result);
+    explicit Store_result_helper(std::vector<const Row *> *result);
     std::function<int64(const Row &)> *get_result_callback();
 
    private:

client/dump/abstract_connection_provider.h

@@ -37,7 +37,7 @@ namespace Dump {
 
 class Abstract_connection_provider : public I_connection_provider {
  protected:
-  Abstract_connection_provider(
+  explicit Abstract_connection_provider(
       Mysql::Tools::Base::I_connection_factory *connection_factory);
 
   virtual Mysql::Tools::Base::Mysql_query_runner *create_new_runner(
@@ -49,7 +49,7 @@ class Abstract_connection_provider : public I_connection_provider {
 
   class Message_handler_wrapper {
    public:
-    Message_handler_wrapper(
+    explicit Message_handler_wrapper(
         std::function<bool(const Mysql::Tools::Base::Message_data &)>
             *message_handler);
 

client/dump/abstract_database_dump_task.h

@@ -37,7 +37,7 @@ namespace Dump {
  */
 class Abstract_database_dump_task : public Abstract_dump_task {
  public:
-  Abstract_database_dump_task(Database *related_database);
+  explicit Abstract_database_dump_task(Database *related_database);
 
   /**
     Returns database the current task is created for.

client/dump/abstract_dump_task.h

@@ -42,7 +42,7 @@ namespace Dump {
 */
 class Abstract_dump_task : public Abstract_simple_dump_task {
  public:
-  Abstract_dump_task(Abstract_data_object *related_object);
+  explicit Abstract_dump_task(Abstract_data_object *related_object);
 
   ~Abstract_dump_task() override;
 

client/dump/abstract_table_dump_task.h

@@ -37,7 +37,7 @@ namespace Dump {
  */
 class Abstract_table_dump_task : public Abstract_dump_task {
  public:
-  Abstract_table_dump_task(Table *related_table);
+  explicit Abstract_table_dump_task(Table *related_table);
 
   /**
     Returns table the current task is created for.

client/dump/chain_data.h

@@ -33,7 +33,7 @@ namespace Dump {
 
 class Chain_data {
  public:
-  Chain_data(uint64 chain_id);
+  explicit Chain_data(uint64 chain_id);
 
   void abort();
 

client/dump/composite_message_handler.h

@@ -43,7 +43,7 @@ class Composite_message_handler {
               &message_handlers);
 
  private:
-  Composite_message_handler(
+  explicit Composite_message_handler(
       const std::vector<
           std::function<bool(const Mysql::Tools::Base::Message_data &)> *>
           &message_handlers);

client/dump/database_end_dump_task.h

@@ -34,7 +34,7 @@ namespace Dump {
 
 class Database_end_dump_task : public Abstract_database_dump_task {
  public:
-  Database_end_dump_task(Database *related_database);
+  explicit Database_end_dump_task(Database *related_database);
 
   ~Database_end_dump_task() override;
 };

client/dump/database_start_dump_task.h

@@ -33,7 +33,7 @@ namespace Dump {
 
 class Database_start_dump_task : public Abstract_database_dump_task {
  public:
-  Database_start_dump_task(Database *related_database);
+  explicit Database_start_dump_task(Database *related_database);
 };
 
 }  // namespace Dump

client/dump/mysql_chain_element_options.h

@@ -35,7 +35,7 @@ namespace Dump {
 class Mysql_chain_element_options
     : public Mysql::Tools::Base::Options::Abstract_options_provider {
  public:
-  Mysql_chain_element_options(
+  explicit Mysql_chain_element_options(
       Mysql::Tools::Base::Abstract_connection_program *program);
 
   void create_options() override;

client/dump/mysql_field.h

@@ -37,7 +37,7 @@ namespace Dump {
 
 class Mysql_field {
  public:
-  Mysql_field(MYSQL_FIELD *field);
+  explicit Mysql_field(MYSQL_FIELD *field);
 
   std::string get_name() const;
 

client/dump/mysql_object_reader_options.h

@@ -38,7 +38,7 @@ namespace Dump {
 class Mysql_object_reader_options
     : public Mysql::Tools::Base::Options::Abstract_options_provider {
  public:
-  Mysql_object_reader_options(
+  explicit Mysql_object_reader_options(
       const Mysql_chain_element_options *mysql_chain_element_options);
 
   void create_options() override;

client/dump/mysqldump_tool_chain_maker_options.h

@@ -42,7 +42,7 @@ extern bool use_show_create_user;
 class Mysqldump_tool_chain_maker_options
     : public Mysql::Tools::Base::Options::Composite_options_provider {
  public:
-  Mysqldump_tool_chain_maker_options(
+  explicit Mysqldump_tool_chain_maker_options(
       const Mysql_chain_element_options *mysql_chain_element_options);
 
   ~Mysqldump_tool_chain_maker_options() override;

client/dump/object_filter.h

@@ -40,7 +40,7 @@ namespace Dump {
 class Object_filter
     : public Mysql::Tools::Base::Options::Composite_options_provider {
  public:
-  Object_filter(Mysql::Tools::Base::Abstract_program *program);
+  explicit Object_filter(Mysql::Tools::Base::Abstract_program *program);
 
   void create_options() override;
 

client/dump/row.h

@@ -37,7 +37,7 @@ namespace Dump {
  */
 class Row : public I_data_object {
  public:
-  Row(const Mysql::Tools::Base::Mysql_query_runner::Row &row_data);
+  explicit Row(const Mysql::Tools::Base::Mysql_query_runner::Row &row_data);
 
   ~Row() override;
 

client/dump/sql_formatter_options.h

@@ -45,7 +45,7 @@ enum class enum_gtid_purged_mode : unsigned long {
 class Sql_formatter_options
     : public Mysql::Tools::Base::Options::Abstract_options_provider {
  public:
-  Sql_formatter_options(
+  explicit Sql_formatter_options(
       const Mysql_chain_element_options *mysql_chain_element_options);
 
   void create_options() override;

client/dump/table_deferred_indexes_dump_task.h

@@ -36,7 +36,7 @@ namespace Dump {
  */
 class Table_deferred_indexes_dump_task : public Abstract_table_dump_task {
  public:
-  Table_deferred_indexes_dump_task(Table *related_table);
+  explicit Table_deferred_indexes_dump_task(Table *related_table);
 };
 
 }  // namespace Dump

client/dump/table_definition_dump_task.h

@@ -36,7 +36,7 @@ namespace Dump {
  */
 class Table_definition_dump_task : public Abstract_table_dump_task {
  public:
-  Table_definition_dump_task(Table *related_table);
+  explicit Table_definition_dump_task(Table *related_table);
 
   ~Table_definition_dump_task() override;
 };

client/dump/table_rows_dump_task.h

@@ -36,7 +36,7 @@ namespace Dump {
  */
 class Table_rows_dump_task : public Abstract_table_dump_task {
  public:
-  Table_rows_dump_task(Table *related_table);
+  explicit Table_rows_dump_task(Table *related_table);
 };
 
 }  // namespace Dump

client/dump/thread_specific_connection_provider.h

@@ -40,7 +40,7 @@ namespace Dump {
 class Thread_specific_connection_provider
     : public Abstract_connection_provider {
  public:
-  Thread_specific_connection_provider(
+  explicit Thread_specific_connection_provider(
       Mysql::Tools::Base::I_connection_factory *connection_factory);
   ~Thread_specific_connection_provider() override;
 

client/infix_ostream_it.h

@@ -31,7 +31,7 @@ template <class T>
 class infix_ostream_iterator
     : public std::iterator<std::output_iterator_tag, T> {
  public:
-  infix_ostream_iterator(std::ostream &s) : m_os(&s) {}
+  explicit infix_ostream_iterator(std::ostream &s) : m_os(&s) {}
 
   infix_ostream_iterator(std::ostream &s, const char *d)
       : m_os(&s), m_delimiter(d) {}

client/logger.h

@@ -35,7 +35,7 @@ std::ostream &operator<<(std::ostream &os, const Datetime &dt);
 
 class Gen_spaces {
  public:
-  Gen_spaces(int s) { m_spaces.assign(s, ' '); }
+  explicit Gen_spaces(int s) { m_spaces.assign(s, ' '); }
   std::ostream &operator<<(std::ostream &os) { return os; }
   friend std::ostream &operator<<(std::ostream &os, const Gen_spaces &gen);
 

client/migrate_keyring/migrate_keyring.cc

@@ -56,7 +56,7 @@ Log log_error(std::cerr, "ERROR");
 
 class Migration_setup {
  public:
-  Migration_setup(char *progname) {
+  explicit Migration_setup(char *progname) {
     MY_INIT(progname);
     init_components_subsystem();
     init_connection_basic();

client/migrate_keyring/options.h

@@ -91,7 +91,7 @@ void deinit_connection_basic();
 
 class Mysql_connection {
  public:
-  Mysql_connection(bool connect);
+  explicit Mysql_connection(bool connect);
   ~Mysql_connection();
   bool execute(std::string command);
   bool ok() { return ok_; }

client/mysql_ssl_rsa_setup.cc

@@ -224,7 +224,7 @@ static void free_resources() {
 
 class RSA_priv {
  public:
-  RSA_priv(uint32_t key_size = 2048) : m_key_size(key_size) {}
+  explicit RSA_priv(uint32_t key_size = 2048) : m_key_size(key_size) {}
 
   ~RSA_priv() = default;
 
@@ -253,7 +253,7 @@ class RSA_pub {
 
 class X509_key {
  public:
-  X509_key(const Sql_string_t &version, uint32_t validity = 10 * 365L)
+  explicit X509_key(const Sql_string_t &version, uint32_t validity = 10 * 365L)
       : m_validity(validity) {
     m_subj_prefix << "-subj /CN=MySQL_Server_" << version;
   }
@@ -312,7 +312,7 @@ class X509v3_ext_writer {
 
 class X509_cert {
  public:
-  X509_cert(uint32_t validity = 10 * 365L) : m_validity(validity) {}
+  explicit X509_cert(uint32_t validity = 10 * 365L) : m_validity(validity) {}
 
   ~X509_cert() = default;
 

client/mysqlbinlog.cc

@@ -125,7 +125,8 @@ class Database_rewrite {
       unsigned char **m_buffer{nullptr};
 
      public:
-      Buffer_realloc_manager(unsigned char **buffer) : m_buffer{buffer} {}
+      explicit Buffer_realloc_manager(unsigned char **buffer)
+          : m_buffer{buffer} {}
       ~Buffer_realloc_manager() {
         if (m_buffer != nullptr) free(*m_buffer);
       }
@@ -209,7 +210,7 @@ class Database_rewrite {
     }
 
    public:
-    Transaction_payload_content_rewriter(Database_rewrite &rewriter)
+    explicit Transaction_payload_content_rewriter(Database_rewrite &rewriter)
         : m_event_rewriter(rewriter) {}
 
     /**
@@ -2575,7 +2576,7 @@ static void fix_gtid_set(MYSQL_RPL *rpl, uchar *packet_gtid_set) {
 class Destroy_log_event_guard {
  public:
   Log_event **ev_del;
-  Destroy_log_event_guard(Log_event **ev_arg) { ev_del = ev_arg; }
+  explicit Destroy_log_event_guard(Log_event **ev_arg) { ev_del = ev_arg; }
   ~Destroy_log_event_guard() {
     if (*ev_del != nullptr) delete *ev_del;
   }

libmysql/authentication_kerberos/auth_kerberos_client_io.h

@@ -27,7 +27,7 @@
 
 class Kerberos_client_io {
  public:
-  Kerberos_client_io(MYSQL_PLUGIN_VIO *vio);
+  explicit Kerberos_client_io(MYSQL_PLUGIN_VIO *vio);
   ~Kerberos_client_io();
   bool write_gssapi_buffer(const unsigned char *buffer, int buffer_len);
   bool read_gssapi_buffer(unsigned char **gssapi_buffer, size_t *buffer_len);

libmysql/authentication_win/common.h

@@ -166,7 +166,7 @@ class Blob {
   Blob(const byte *ptr, const size_t len)
       : m_ptr(const_cast<byte *>(ptr)), m_len(len) {}
 
-  Blob(const char *str)
+  explicit Blob(const char *str)
       : m_ptr(const_cast<byte *>(reinterpret_cast<const byte *>(str))) {
     m_len = strlen(str);
   }
@@ -202,7 +202,7 @@ class Connection {
   int m_error;
 
  public:
-  Connection(MYSQL_PLUGIN_VIO *vio);
+  explicit Connection(MYSQL_PLUGIN_VIO *vio);
   int write(const Blob &);
   Blob read();
 
@@ -220,8 +220,8 @@ class Sid {
   SID_NAME_USE m_type;  ///< Type of identified entity.
 
  public:
-  Sid(const wchar_t *);
-  Sid(HANDLE sec_token);
+  explicit Sid(const wchar_t *);
+  explicit Sid(HANDLE sec_token);
   ~Sid();
 
   bool is_valid(void) const;

libmysql/authentication_win/handshake.h

@@ -66,7 +66,7 @@ class Security_buffer : public SecBufferDesc {
   const Security_buffer &operator=(const Security_buffer &);
 
  public:
-  Security_buffer(const Blob &);
+  explicit Security_buffer(const Blob &);
   Security_buffer();
 
   ~Security_buffer() { mem_free(); }

libmysql/test_trace_plugin.cc

@@ -182,7 +182,7 @@ class Logger {
 
  public:
   Logger() : connection_id(0), end(buffer) {}
-  Logger(MYSQL *conn);
+  explicit Logger(MYSQL *conn);
   void log(const char *format, ...) MY_ATTRIBUTE((format(printf, 2, 3)));
   void dump(const char *key, const void *data, size_t len);
 };

sql-common/oci/signing_key.h

@@ -45,7 +45,7 @@ class Signing_Key {
 
  public:
   Signing_Key(const std::string &file_name);
-  Signing_Key(ssl::Key_Content);
+  explicit Signing_Key(ssl::Key_Content);
   Signing_Key();
   Signing_Key(const Signing_Key &) = delete;
   Signing_Key &operator=(const Signing_Key &) = delete;