diff options
| -rw-r--r-- | odb/mysql/connection-factory.cxx | 39 |
1 files changed, 38 insertions, 1 deletions
diff --git a/odb/mysql/connection-factory.cxx b/odb/mysql/connection-factory.cxx index 645d03a..aae5cb9 100644 --- a/odb/mysql/connection-factory.cxx +++ b/odb/mysql/connection-factory.cxx @@ -3,6 +3,12 @@ // copyright : Copyright (c) 2009-2010 Code Synthesis Tools CC // license : GNU GPL v2; see accompanying LICENSE file +#include <odb/details/config.hxx> // ODB_THREADS_* + +#ifdef ODB_THREADS_POSIX +# include <pthread.h> +#endif + #include <cstdlib> // abort #include <odb/mysql/mysql.hxx> @@ -11,7 +17,25 @@ #include <odb/details/tls.hxx> #include <odb/details/lock.hxx> -#include <odb/details/config.hxx> // ODB_THREADS_NONE + +// This key is in the mysql client library. We use it to resolve the +// following problem: Some pthread implementations zero-out slots that +// don't have destructors during thread termination. As a result, when +// out destructor gets called and we call mysql_thread_end(), the thread- +// specific slot used by MySQL may have been reset to 0 and as a result +// MySQL thinks the data has been freed. +// +// To work around this problem we are going to cache the MySQL's slot +// value and if, during destruction, we see that it is 0, we will restore +// the original value before calling mysql_thread_end(). This will work +// fine for as long as the following conditions are met: +// +// 1. MySQL don't use the destructor itself. +// 2. Nobody else tried to call mysql_thread_end() before us. +// +#ifdef ODB_THREADS_POSIX +extern pthread_key_t THR_KEY_mysys; +#endif using namespace std; @@ -40,18 +64,31 @@ namespace odb } init_ = true; + +#ifdef ODB_THREADS_POSIX + value_ = pthread_getspecific (THR_KEY_mysys); +#endif } } ~mysql_thread_init () { if (init_) + { +#ifdef ODB_THREADS_POSIX + if (pthread_getspecific (THR_KEY_mysys) == 0) + pthread_setspecific (THR_KEY_mysys, value_); +#endif mysql_thread_end (); + } } private: bool init_; +#ifdef ODB_THREADS_POSIX + void* value_; #endif +#endif // ODB_THREADS_NONE }; static ODB_TLS_OBJECT (mysql_thread_init) mysql_thread_init_; |