1 files changed, 70 insertions, 0 deletions
diff --git a/src/mongo/db/commands/hashcmd.cpp b/src/mongo/db/commands/hashcmd.cpp
new file mode 100644
index 00000000000..f4f85c0e02b
--- /dev/null
+++ b/src/mongo/db/commands/hashcmd.cpp
@@ -0,0 +1,70 @@
+/* hashcmd.cpp
+ *
+ * Defines a shell command for hashing a BSONElement value
+ */
+
+
+/**
+*    Copyright (C) 2012 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/>.
+*/
+
+#include "mongo/db/commands.h"
+#include "mongo/db/hasher.h"
+
+namespace mongo {
+
+    class CmdHashElt : public Command {
+    public:
+        CmdHashElt() : Command("_hashBSONElement") {};
+        virtual LockType locktype() const { return NONE; }
+        virtual bool slaveOk() const { return true; }
+        virtual void help( stringstream& help ) const {
+            help << "returns the hash of the first BSONElement val in a BSONObj";
+        }
+
+        /* CmdObj has the form {"hash" : <thingToHash>}
+         * or {"hash" : <thingToHash>, "seed" : <number> }
+         * Result has the form
+         * {"key" : <thingTohash>, "seed" : <int>, "out": NumberLong(<hash>)}
+         *
+         * Example use in the shell:
+         *> db.runCommand({hash: "hashthis", seed: 1})
+         *> {"key" : "hashthis",
+         *>  "seed" : 1,
+         *>  "out" : NumberLong(6271151123721111923),
+         *>  "ok" : 1 }
+         **/
+        bool run( const string& db,
+                  BSONObj& cmdObj,
+                  int options, string& errmsg,
+                  BSONObjBuilder& result,
+                  bool fromRepl = false ){
+            result.appendAs(cmdObj.firstElement(),"key");
+
+            int seed = 0;
+            if (cmdObj.hasField("seed")){
+                if (! cmdObj["seed"].isNumber()) {
+                    errmsg += "seed must be a number";
+                    return false;
+                }
+                seed = cmdObj["seed"].numberInt();
+            }
+            result.append( "seed" , seed );
+
+            result.append( "out" , BSONElementHasher::hash64( cmdObj.firstElement() , seed ) );
+            return true;
+        }
+    } cmdHashElt;
+}