Merge pull request tecbot#150 from jialeicui/rocksdb_get_options_from…

…_string

add wrapper for GetOptionsFromString

options.go

@@ -3,7 +3,10 @@ package gorocksdb
 // #include "rocksdb/c.h"
 // #include "gorocksdb.h"
 import "C"
-import "unsafe"
+import (
+	"errors"
+	"unsafe"
+)
 
 // CompressionType specifies the block compression.
 // DB contents are stored in a set of blocks, each of which holds a
@@ -82,6 +85,30 @@ func NewNativeOptions(c *C.rocksdb_options_t) *Options {
 	return &Options{c: c}
 }
 
+// GetOptionsFromString creates a Options object from existing opt and string.
+// If base is nil, a default opt create by NewDefaultOptions will be used as base opt.
+func GetOptionsFromString(base *Options, optStr string) (*Options, error) {
+	if base == nil {
+		base = NewDefaultOptions()
+		defer base.Destroy()
+	}
+
+	var (
+		cErr    *C.char
+		cOptStr = C.CString(optStr)
+	)
+	defer C.free(unsafe.Pointer(cOptStr))
+
+	newOpt := NewDefaultOptions()
+	C.rocksdb_get_options_from_string(base.c, cOptStr, newOpt.c, &cErr)
+	if cErr != nil {
+		defer C.free(unsafe.Pointer(cErr))
+		return nil, errors.New(C.GoString(cErr))
+	}
+
+	return newOpt, nil
+}
+
 // -------------------
 // Parameters that affect behavior