ConnPool::getConn() now throws an exception if the pool was configured with zero connections

rdbms/ConnPool.cpp

@@ -42,6 +42,11 @@ ConnPool::ConnPool(const Login &login, const uint64_t maxNbConns):
 Conn ConnPool::getConn() {
   threading::MutexLocker locker(m_connsAndStmtsMutex);
 
+  if(0 == m_maxNbConns) {
+    throw ConnPoolConfiguredWithZeroConns(std::string(__FUNCTION__) +
+      " failed: ConnPool is configured with zero connections");
+  }
+
   while(m_connsAndStmts.size() == 0 && m_nbConnsOnLoan == m_maxNbConns) {
     m_connsAndStmtsCv.wait(locker);
   }

rdbms/ConnPool.hpp

@@ -18,6 +18,7 @@
 
 #pragma once
 
+#include "common/exception/Exception.hpp"
 #include "common/threading/CondVar.hpp"
 #include "common/threading/Mutex.hpp"
 #include "rdbms/ConnAndStmts.hpp"
@@ -49,14 +50,20 @@ public:
    */
   ConnPool(const Login &login, const uint64_t maxNbConns);
 
+  CTA_GENERATE_EXCEPTION_CLASS(ConnPoolConfiguredWithZeroConns);
+
   /**
    * Takes a connection from the pool.
    *
    * Please note that this method will block if the pool is empty.  In such a
    * situation this method will unblock when a connection is returned to the
-   * pool.
+   * pool.  There is one exception to this rule.  If the pool was configured
+   * with maxNbConns set to 0 then calling this method with throw a
+   * ConnPoolConfiguredWithZeroConns exception.
    *
    * @return A connection from the pool.
+   * @throw ConnPoolConfiguredWithZeroConns If this pool was configured with
+   * maxNbConns set to 0.
    */
   Conn getConn();
 

rdbms/ConnPoolTest.cpp

@@ -38,18 +38,28 @@ TEST_F(cta_rdbms_ConnPoolTest, getPooledConn) {
   using namespace cta::rdbms;
 
   const Login login(Login::DBTYPE_SQLITE, "", "", "file::memory:?cache=shared", "", 0);
-  const uint64_t nbConns = 2;
-  ConnPool pool(login, nbConns);
+  const uint64_t maxNbConns = 2;
+  ConnPool pool(login, maxNbConns);
 
   Conn conn = pool.getConn();
 }
 
+TEST_F(cta_rdbms_ConnPoolTest, getPooledConn_maxNbConns_zero) {
+  using namespace cta::rdbms;
+
+  const Login login(Login::DBTYPE_SQLITE, "", "", "file::memory:?cache=shared", "", 0);
+  const uint64_t maxNbConns = 0;
+  ConnPool pool(login, maxNbConns);
+
+  ASSERT_THROW(Conn conn = pool.getConn(), ConnPool::ConnPoolConfiguredWithZeroConns);
+}
+
 TEST_F(cta_rdbms_ConnPoolTest, assignment) {
   using namespace cta::rdbms;
 
   const Login login(Login::DBTYPE_SQLITE, "", "", "file::memory:?cache=shared", "", 0);
-  const uint64_t nbConns = 2;
-  ConnPool pool(login, nbConns);
+  const uint64_t maxNbConns = 2;
+  ConnPool pool(login, maxNbConns);
 
   Conn conn = pool.getConn();
 
@@ -62,8 +72,8 @@ TEST_F(cta_rdbms_ConnPoolTest, moveConstructor) {
   using namespace cta::rdbms;
 
   const Login login(Login::DBTYPE_SQLITE, "", "", "file::memory:?cache=shared", "", 0);
-  const uint64_t nbConns = 2;
-  ConnPool pool(login, nbConns);
+  const uint64_t maxNbConns = 2;
+  ConnPool pool(login, maxNbConns);
 
   Conn conn = pool.getConn();