move connpool to client folder

2 files changed, 124 insertions, 0 deletions

diff --git a/client/connpool.cpp b/client/connpool.cpp
new file mode 100644
index 00000000000..d997aa49e2d
--- /dev/null
+++ b/client/connpool.cpp
@@ -0,0 +1,46 @@
+/* connpool.cpp
+*/
+
+/**
+*    Copyright (C) 2008 10gen Inc.
+*  
+*    This program is free software: you can redistribute it and/or  modify
+*    it under the terms of the GNU Affero General Public License, version 3,
+*    as published by the Free Software Foundation.
+*  
+*    This program is distributed in the hope that it will be useful,
+*    but WITHOUT ANY WARRANTY; without even the implied warranty of
+*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*    GNU Affero General Public License for more details.
+*  
+*    You should have received a copy of the GNU Affero General Public License
+*    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+// _ todo: reconnect?
+
+#include "stdafx.h"
+#include "connpool.h"
+
+DBConnectionPool pool;
+
+DBClientConnection* DBConnectionPool::get(const string& host) { 
+    boostlock L(poolMutex);
+
+    PoolForHost *&p = pools[host];
+    if( p == 0 )
+        p = new PoolForHost();
+    if( p->pool.empty() ) {
+        string errmsg;
+        DBClientConnection *c = new DBClientConnection();
+        if( !c->connect(host.c_str(), errmsg) ) { 
+            delete c;
+            uassert("dbconnectionpool: connect failed", false);
+            return 0;
+        }
+        return c;
+    }
+    DBClientConnection *c = p->pool.front();
+    p->pool.pop();
+    return c;
+}
diff --git a/client/connpool.h b/client/connpool.h
new file mode 100644
index 00000000000..6a4b5d92f00
--- /dev/null
+++ b/client/connpool.h
@@ -0,0 +1,78 @@
+/* connpool.h */
+
+/**
+*    Copyright (C) 2008 10gen Inc.
+*  
+*    This program is free software: you can redistribute it and/or  modify
+*    it under the terms of the GNU Affero General Public License, version 3,
+*    as published by the Free Software Foundation.
+*  
+*    This program is distributed in the hope that it will be useful,
+*    but WITHOUT ANY WARRANTY; without even the implied warranty of
+*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*    GNU Affero General Public License for more details.
+*  
+*    You should have received a copy of the GNU Affero General Public License
+*    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <queue>
+#include "dbclient.h"
+
+struct PoolForHost { 
+    queue<DBClientConnection*> pool;
+};
+
+class DBConnectionPool { 
+    boost::mutex poolMutex;
+    map<string,PoolForHost*> pools;
+public:
+
+    /* generally, use ScopedDbConnection and do not call these directly */
+    DBClientConnection *get(const string& host);
+    void release(const string& host, DBClientConnection *c) { 
+        boostlock L(poolMutex);
+        pools[host]->pool.push(c);
+    }
+};
+
+extern DBConnectionPool pool;
+
+/* Use to get a connection from the pool.  On exceptions things
+   clean up nicely.
+*/
+class ScopedDbConnection { 
+    const string host; 
+    DBClientConnection *_conn;
+public:
+    DBClientConnection& conn() { return *_conn; }
+
+    /* throws UserAssertionAcception if can't connect */
+    ScopedDbConnection(const string& _host) : 
+      host(_host), _conn( pool.get(_host) ) { }
+
+    /* Call this when you are done with the ocnnection. 
+         Why?  See note in the destructor below.
+    */
+    void done() { 
+        if( _conn->isFailed() ) 
+            delete _conn;
+        else
+            pool.release(host, _conn);
+        _conn = 0;
+    }
+
+    ~ScopedDbConnection() {
+        if( _conn ) { 
+            /* you are supposed to call done().  if you did that, correctly, we 
+               only get here if an exception was thrown.  in such a scenario, we can't 
+               be sure we fully read all expected data of a reply on the socket.  so 
+               we don't try to reuse the connection.  The cout is just informational.
+               */
+            cout << "~ScopedDBConnection: _conn != null\n";
+            delete _conn;
+        }
+    }
+};