Env info on existing tx (#29)

Author: AskAlexSharov

Makefile

@@ -22,7 +22,7 @@ lint:
 
 lintci-deps:
 	rm -f ./build/bin/golangci-lint
-	curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b ./build/bin v1.41.0
+	curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b ./build/bin v1.41.1
 
 check:
 	which goimports > /dev/null

exp/mdbxpool/txnpool.go

@@ -50,15 +50,15 @@ const (
 // updates and prevent long-lived updates from causing excessive disk
 // utilization.
 type TxnPool struct {
+	env  *mdbx.Env
+	pool sync.Pool
 	// UpdateHandling determines how a TxnPool behaves after updates have been
 	// committed.  It is not safe to modify UpdateHandling if TxnPool is being
 	// used concurrently.
 	UpdateHandling UpdateHandling
 
 	lastid    uintptr
 	idleGuard uintptr
-	env       *mdbx.Env
-	pool      sync.Pool
 }
 
 // NewTxnPool initializes returns a new TxnPool.

mdbx/env.go

@@ -349,15 +349,18 @@ type EnvInfo struct {
 // Info returns information about the environment.
 //
 // See mdbx_env_info.
-func (env *Env) Info() (*EnvInfo, error) {
-	var _info C.MDBX_envinfo
-	var ret C.int
-	if err := env.View(func(txn *Txn) error {
-		ret = C.mdbx_env_info_ex(env._env, txn._txn, &_info, C.size_t(unsafe.Sizeof(_info)))
-		return nil
-	}); err != nil {
-		return nil, err
+// txn - can be nil
+func (env *Env) Info(txn *Txn) (*EnvInfo, error) {
+	if txn == nil {
+		var err error
+		txn, err = env.BeginTxn(nil, Readonly)
+		if err != nil {
+			return nil, err
+		}
+		defer txn.Abort()
 	}
+	var _info C.MDBX_envinfo
+	ret := C.mdbx_env_info_ex(env._env, txn._txn, &_info, C.size_t(unsafe.Sizeof(_info)))
 	if ret != success {
 		return nil, operrno("mdbx_env_info", ret)
 	}

mdbx/error.go

@@ -16,8 +16,8 @@ import (
 // lmdb-go have type OpError but typically they do.  The Errno field will
 // either have type Errno or syscall.Errno.
 type OpError struct {
-	Op    string
 	Errno error
+	Op    string
 }
 
 // Error implements the error interface.

mdbx/error_test.go

@@ -7,7 +7,7 @@ import (
 )
 
 func TestErrno_Error(t *testing.T) {
-	operr := &OpError{"testop", fmt.Errorf("testmsg")}
+	operr := &OpError{fmt.Errorf("testmsg"), "testop"}
 	msg := operr.Error()
 	if msg != "testop: testmsg" {
 		t.Errorf("message: %q", msg)
@@ -21,7 +21,7 @@ func BenchmarkErrno_Error(b *testing.B) {
 			NotFound,
 			MapFull,
 		} {
-			operr := &OpError{"mdb_testop", errno}
+			operr := &OpError{errno, "mdb_testop"}
 			msg := operr.Error()
 			if msg == "" {
 				b.Fatal("empty message")