kv: In memory keyvalue db implementation

Signed-off-by: Ramesh Chander <Ramesh.Chander@sandisk.com>

src/include/encoding.h

@@ -1018,4 +1018,32 @@ inline void decode(std::deque<T>& ls, bufferlist::iterator& p)
       bl.advance(struct_end - bl.get_off());				\
   }
 
+/*
+ * Encoders/decoders to read from current offset in a file handle and
+ * encode/decode the data according to argument types.
+ */
+inline ssize_t decode_file(int fd, std::string &str)
+{
+  bufferlist bl;
+  __u32 len = 0;
+  bl.read_fd(fd, sizeof(len));
+  decode(len, bl);                                                                                                  
+  bl.read_fd(fd, len);
+  decode(str, bl);                                                                                                  
+  return bl.length();
+}
+
+inline ssize_t decode_file(int fd, bufferptr &bp)
+{
+  bufferlist bl;
+  __u32 len = 0;
+  bl.read_fd(fd, sizeof(len));
+  decode(len, bl);                                                                                                  
+  bl.read_fd(fd, len);
+  bufferlist::iterator bli = bl.begin();
+
+  decode(bp, bli);                                                                                                  
+  return bl.length();
+}
+
 #endif

src/kv/KeyValueDB.cc

@@ -3,6 +3,7 @@
 
 #include "KeyValueDB.h"
 #include "LevelDBStore.h"
+#include "MemDBStore.h"
 #ifdef HAVE_LIBROCKSDB
 #include "RocksDBStore.h"
 #endif
@@ -29,6 +30,11 @@ KeyValueDB *KeyValueDB::create(CephContext *cct, const string& type,
     return new RocksDBStore(cct, dir, p);
   }
 #endif
+
+  if ((type == "memdb") && 
+    cct->check_experimental_feature_enabled("memdb")) {
+    return new MSStore(cct, dir, p);
+  }
   return NULL;
 }
 
@@ -47,5 +53,9 @@ int KeyValueDB::test_init(const string& type, const string& dir)
     return RocksDBStore::_test_init(dir);
   }
 #endif
+
+  if (type == "memdb") {
+    return MSStore::_test_init(dir);
+  }
   return -EINVAL;
 }

src/kv/KeyValueDB.h

@@ -124,6 +124,7 @@ class KeyValueDB {
   virtual int init(string option_str="") = 0;
   virtual int open(std::ostream &out) = 0;
   virtual int create_and_open(std::ostream &out) = 0;
+  virtual void close() { }
 
   virtual Transaction get_transaction() = 0;
   virtual int submit_transaction(Transaction) = 0;

src/kv/Makefile.am

@@ -51,4 +51,8 @@ libkv_a_LIBADD += -lkinetic_client -lprotobuf -lglog -lgflags libcrypto.a
 noinst_HEADERS += kv/KineticStore.h
 endif
 
+libkv_a_SOURCES += kv/MemDBStore.cc
+noinst_HEADERS += kv/MemDBStore.h
+
+
 endif # ENABLE_SERVER