FD reviving (#200)

* FD reviving

* FD reviving

* FD reviving

* FD reviving

---------

Co-authored-by: JkLondon <me@ilyamikheev.com>

Author: JkLondon

mdbx/env.go

@@ -173,34 +173,6 @@ func (env *Env) SetStrictThreadMode(mode bool) {
 
 var errNotOpen = errors.New("enivornment is not open")
 
-/* TODO: fix error: cannot convert *mf (variable of type _Ctype_HANDLE) to type uintptr
-
-// FD returns the open file descriptor (or Windows file handle) for the given
-// environment.  An error is returned if the environment has not been
-// successfully Opened (where C API just retruns an invalid handle).
-//
-// See mdbx_env_get_fd.
-func (env *Env) FD() (uintptr, error) {
-	// fdInvalid is the value -1 as a uintptr, which is used by MDBX in the
-	// case that env has not been opened yet.  the strange construction is done
-	// to avoid constant value overflow errors at compile time.
-	const fdInvalid = ^uintptr(0)
-
-	mf := new(C.mdbx_filehandle_t)
-	ret := C.mdbx_env_get_fd(env._env, mf)
-	err := operrno("mdbx_env_get_fd", ret)
-	if err != nil {
-		return 0, err
-	}
-	fd := uintptr(*mf)
-
-	if fd == fdInvalid {
-		return 0, errNotOpen
-	}
-	return fd, nil
-}
-*/
-
 // ReaderList dumps the contents of the reader lock table as text.  Readers
 // start on the second line as space-delimited fields described by the first
 // line.

mdbx/env_not_win.go

@@ -24,3 +24,28 @@ import "C"
 //	}
 //	return C.GoString(cpath), nil
 //}
+
+// FD returns the open file descriptor (or Windows file handle) for the given
+// environment.  An error is returned if the environment has not been
+// successfully Opened (where C API just retruns an invalid handle).
+//
+// See mdbx_env_get_fd.
+func (env *Env) FD() (uintptr, error) {
+	// fdInvalid is the value -1 as a uintptr, which is used by MDBX in the
+	// case that env has not been opened yet.  the strange construction is done
+	// to avoid constant value overflow errors at compile time.
+	const fdInvalid = ^uintptr(0)
+
+	mf := new(C.mdbx_filehandle_t)
+	ret := C.mdbx_env_get_fd(env._env, mf)
+	err := operrno("mdbx_env_get_fd", ret)
+	if err != nil {
+		return 0, err
+	}
+	fd := uintptr(*mf)
+
+	if fd == fdInvalid {
+		return 0, errNotOpen
+	}
+	return fd, nil
+}

mdbx/env_test.go

@@ -2,6 +2,8 @@ package mdbx
 
 import (
 	"fmt"
+	"runtime"
+	"strings"
 	"testing"
 )
 
@@ -99,12 +101,11 @@ func TestEnv_PreOpen(t *testing.T) {
 
 }
 
-/*
 func TestEnv_FD(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.Skip("FD funcs not supported on windows")
 	}
-	env, err1 := NewEnv()
+	env, err1 := NewEnv(Default)
 	if err1 != nil {
 		t.Error(err1)
 		return
@@ -131,7 +132,6 @@ func TestEnv_FD(t *testing.T) {
 		t.Errorf("fd: %x", fd)
 	}
 }
-*/
 
 func TestEnv_Flags(t *testing.T) {
 	env, _ := setup(t)

mdbx/env_windows.go

@@ -4,6 +4,7 @@ package mdbx
 #include "mdbxgo.h"
 */
 import "C"
+import "unsafe"
 
 // TODO: fix me please
 //func (env *Env) Path() (string, error) {
@@ -17,3 +18,28 @@ import "C"
 //	}
 //	return C.GoString(cpath), nil
 //}
+
+// FD returns the open file descriptor (or Windows file handle) for the given
+// environment.  An error is returned if the environment has not been
+// successfully Opened (where C API just retruns an invalid handle).
+//
+// See mdbx_env_get_fd.
+func (env *Env) FD() (uintptr, error) {
+	// fdInvalid is the value -1 as a uintptr, which is used by MDBX in the
+	// case that env has not been opened yet.  the strange construction is done
+	// to avoid constant value overflow errors at compile time.
+	const fdInvalid = ^uintptr(0)
+
+	var fh C.mdbx_filehandle_t
+	ret := C.mdbx_env_get_fd(env._env, &fh)
+	err := operrno("mdbx_env_get_fd", ret)
+	if err != nil {
+		return 0, err
+	}
+	fd := uintptr(unsafe.Pointer(fh))
+
+	if fd == fdInvalid {
+		return 0, errNotOpen
+	}
+	return fd, nil
+}