From 41f728d8553d4797acfeea85cf59238dbfa84274 Mon Sep 17 00:00:00 2001
From: pnevezhin <pnevezhin@tradingview.com>
Date: Wed, 8 Feb 2017 16:08:00 +0300
Subject: [PATCH] refactor: small fixes and addition of comments

---
 cursor.go      | 10 ++++++----
 database.go    |  9 +++++----
 document.go    |  8 ++++++--
 environment.go |  5 ++++-
 transaction.go |  7 ++++++-
 var_store.go   |  2 +-
 wrappers.go    | 15 ++-------------
 7 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/cursor.go b/cursor.go
index 5772a35..61efa05 100644
--- a/cursor.go
+++ b/cursor.go
@@ -56,7 +56,10 @@ func (cur *cursor) Close() error {
 	}
 	cur.doc.Free()
 	cur.closed = true
-	return spDestroy(cur.ptr)
+	if !spDestroy(cur.ptr) {
+		return errors.New("cursor: failed to close")
+	}
+	return nil
 }
 
 // Next fetches the next row for the cursor
@@ -69,7 +72,6 @@ func (cur *cursor) Next() *Document {
 	if ptr == nil {
 		return nil
 	}
-	d := newDocument(ptr, 0)
-	cur.doc = d
-	return d
+	cur.doc.ptr = ptr
+	return cur.doc
 }
diff --git a/database.go b/database.go
index a274146..2c4d182 100644
--- a/database.go
+++ b/database.go
@@ -1,6 +1,7 @@
 package sophia
 
 import (
+	"errors"
 	"fmt"
 )
 
@@ -25,12 +26,12 @@ func (db *Database) Document() *Document {
 
 // Cursor returns a Cursor for iterating over rows in the database
 func (db *Database) Cursor(doc *Document) (Cursor, error) {
+	if nil == doc {
+		return nil, errors.New("failed to create cursor: nil Document")
+	}
 	cPtr := spCursor(db.env.ptr)
 	if nil == cPtr {
-		return nil, fmt.Errorf("failed create cursor: err=%v", db.env.Error())
-	}
-	if nil == doc {
-		return nil, fmt.Errorf("failed get document: err=%v", db.env.Error())
+		return nil, fmt.Errorf("failed to create cursor: err=%v", db.env.Error())
 	}
 	cur := &cursor{
 		ptr: cPtr,
diff --git a/document.go b/document.go
index 2e04b4c..428c3c7 100644
--- a/document.go
+++ b/document.go
@@ -1,6 +1,7 @@
 package sophia
 
 import (
+	"errors"
 	"unsafe"
 )
 
@@ -14,6 +15,9 @@ func newDocument(ptr unsafe.Pointer, size int) *Document {
 	}
 }
 
-func (d *Document) Destroy() {
-	spDestroy(d.ptr)
+func (d *Document) Destroy() error {
+	if !spDestroy(d.ptr) {
+		return errors.New("document: failed to destroy")
+	}
+	return nil
 }
diff --git a/environment.go b/environment.go
index 907a547..2c7baa2 100644
--- a/environment.go
+++ b/environment.go
@@ -55,7 +55,10 @@ func (env *Environment) NewDatabase(name string, schema *Schema) (*Database, err
 // Close on any Environment created with NewEnvironment.
 func (env *Environment) Close() error {
 	env.Free()
-	return spDestroy(env.ptr)
+	if !spDestroy(env.ptr) {
+		return errors.New("env: failed to close")
+	}
+	return nil
 }
 
 // Open opens environment
diff --git a/transaction.go b/transaction.go
index 5135255..3708aa0 100644
--- a/transaction.go
+++ b/transaction.go
@@ -1,5 +1,7 @@
 package sophia
 
+import "errors"
+
 // TxStatus transactional status
 type TxStatus int
 
@@ -35,5 +37,8 @@ func (tx *Transaction) Commit() TxStatus {
 
 // Rollback rollbacks transaction and destroy transaction object.
 func (tx *Transaction) Rollback() error {
-	return spDestroy(tx.ptr)
+	if !spDestroy(tx.ptr) {
+		return errors.New("tx: failed to rollback")
+	}
+	return nil
 }
diff --git a/var_store.go b/var_store.go
index 2950f99..3d17160 100644
--- a/var_store.go
+++ b/var_store.go
@@ -65,7 +65,6 @@ func (s *varStore) GetString(path string, size *int) string {
 }
 
 func (s *varStore) GetObject(path string) unsafe.Pointer {
-
 	return spGetObject(s.ptr, getCStringFromCache(path))
 }
 
@@ -74,6 +73,7 @@ func (s *varStore) GetInt(path string) int64 {
 }
 
 // Free frees allocated memory for all C variables, that were in this store
+// This always should be called to prevent memory leaks
 func (s *varStore) Free() {
 	for _, f := range s.pointers {
 		free(f)
diff --git a/wrappers.go b/wrappers.go
index 1651c8b..d2d2336 100644
--- a/wrappers.go
+++ b/wrappers.go
@@ -1,7 +1,6 @@
 package sophia
 
 import (
-	"errors"
 	"unsafe"
 )
 
@@ -25,23 +24,13 @@ extern void    *sp_cursor(void*);
 extern void    *sp_begin(void*);
 extern int      sp_prepare(void*);
 extern int      sp_commit(void*);
-char* pointer_to_string(void* ptr)
-{
-	return (char*)ptr;
-}
 */
 import "C"
 
 // spDestroy wrapper for sp_destroy
 // destroys C sophia object
-func spDestroy(p unsafe.Pointer) error {
-	if nil == p {
-		return nil
-	}
-	if 0 != C.sp_destroy(p) {
-		return errors.New("failed close resource")
-	}
-	return nil
+func spDestroy(p unsafe.Pointer) bool {
+	return C.sp_destroy(p) == 0
 }
 
 // spSetString wrapper for sp_setstring for common cases