move Copy and CopyFile from DB to Tx

db.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"hash/fnv"
-	"io"
 	"os"
 	"strings"
 	"sync"
@@ -483,65 +482,6 @@ func (db *DB) View(fn func(*Tx) error) error {
 	return nil
 }
 
-// Copy writes the entire database to a writer.
-// A reader transaction is maintained during the copy so it is safe to continue
-// using the database while a copy is in progress.
-func (db *DB) Copy(w io.Writer) error {
-	// Maintain a reader transaction so pages don't get reclaimed.
-	t, err := db.Begin(false)
-	if err != nil {
-		return err
-	}
-
-	// Open reader on the database.
-	f, err := os.Open(db.path)
-	if err != nil {
-		_ = t.Rollback()
-		return err
-	}
-
-	// Copy the meta pages.
-	db.metalock.Lock()
-	_, err = io.CopyN(w, f, int64(db.pageSize*2))
-	db.metalock.Unlock()
-	if err != nil {
-		_ = t.Rollback()
-		_ = f.Close()
-		return fmt.Errorf("meta copy: %s", err)
-	}
-
-	// Copy data pages.
-	if _, err := io.Copy(w, f); err != nil {
-		_ = t.Rollback()
-		_ = f.Close()
-		return err
-	}
-
-	// Close read transaction and exit.
-	if err := t.Rollback(); err != nil {
-		_ = f.Close()
-		return err
-	}
-	return f.Close()
-}
-
-// CopyFile copies the entire database to file at the given path.
-// A reader transaction is maintained during the copy so it is safe to continue
-// using the database while a copy is in progress.
-func (db *DB) CopyFile(path string, mode os.FileMode) error {
-	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, mode)
-	if err != nil {
-		return err
-	}
-
-	err = db.Copy(f)
-	if err != nil {
-		_ = f.Close()
-		return err
-	}
-	return f.Close()
-}
-
 // Stats retrieves ongoing performance stats for the database.
 // This is only updated when a transaction closes.
 func (db *DB) Stats() Stats {

db_test.go

@@ -238,30 +238,6 @@ func TestDB_View_Error(t *testing.T) {
 	})
 }
 
-// Ensure that the database can be copied to a file path.
-func TestDB_CopyFile(t *testing.T) {
-	withOpenDB(func(db *DB, path string) {
-		var dest = tempfile()
-		db.Update(func(tx *Tx) error {
-			tx.CreateBucket([]byte("widgets"))
-			tx.Bucket([]byte("widgets")).Put([]byte("foo"), []byte("bar"))
-			tx.Bucket([]byte("widgets")).Put([]byte("baz"), []byte("bat"))
-			return nil
-		})
-		assert.NoError(t, db.CopyFile(dest, 0600))
-
-		db2, err := Open(dest, 0600)
-		assert.NoError(t, err)
-		defer db2.Close()
-
-		db2.View(func(tx *Tx) error {
-			assert.Equal(t, []byte("bar"), tx.Bucket([]byte("widgets")).Get([]byte("foo")))
-			assert.Equal(t, []byte("bat"), tx.Bucket([]byte("widgets")).Get([]byte("baz")))
-			return nil
-		})
-	})
-}
-
 // Ensure that an error is returned when a database write fails.
 func TestDB_Commit_WriteFail(t *testing.T) {
 	t.Skip("pending") // TODO(benbjohnson)
@@ -450,39 +426,6 @@ func ExampleDB_Begin_ReadOnly() {
 	// zephyr likes purple
 }
 
-func ExampleDB_CopyFile() {
-	// Open the database.
-	db, _ := Open(tempfile(), 0666)
-	defer os.Remove(db.Path())
-	defer db.Close()
-
-	// Create a bucket and a key.
-	db.Update(func(tx *Tx) error {
-		tx.CreateBucket([]byte("widgets"))
-		tx.Bucket([]byte("widgets")).Put([]byte("foo"), []byte("bar"))
-		return nil
-	})
-
-	// Copy the database to another file.
-	toFile := tempfile()
-	db.CopyFile(toFile, 0666)
-	defer os.Remove(toFile)
-
-	// Open the cloned database.
-	db2, _ := Open(toFile, 0666)
-	defer db2.Close()
-
-	// Ensure that the key exists in the copy.
-	db2.View(func(tx *Tx) error {
-		value := tx.Bucket([]byte("widgets")).Get([]byte("foo"))
-		fmt.Printf("The value for 'foo' in the clone is: %s\n", value)
-		return nil
-	})
-
-	// Output:
-	// The value for 'foo' in the clone is: bar
-}
-
 // tempfile returns a temporary file path.
 func tempfile() string {
 	f, _ := ioutil.TempFile("", "bolt-")
@@ -523,7 +466,7 @@ func mustCheck(db *DB) {
 	if err := db.Check(); err != nil {
 		// Copy db off first.
 		var path = tempfile()
-		db.CopyFile(path, 0600)
+		db.View(func(tx *Tx) error { return tx.CopyFile(path, 0600) })
 
 		if errors, ok := err.(ErrorList); ok {
 			for _, err := range errors {
@@ -564,7 +507,7 @@ func truncDuration(d time.Duration) string {
 // copyAndFailNow copies a database to a new location and then fails then test.
 func copyAndFailNow(t *testing.T, db *DB) {
 	path := tempfile()
-	db.CopyFile(path, 0600)
+	db.View(func(tx *Tx) error { return tx.CopyFile(path, 0600) })
 	fmt.Println("db copied to: ", path)
 	t.FailNow()
 }

tx.go

@@ -3,6 +3,8 @@ package bolt
 import (
 	"errors"
 	"fmt"
+	"io"
+	"os"
 	"sort"
 	"time"
 	"unsafe"
@@ -227,6 +229,55 @@ func (tx *Tx) close() {
 	tx.db = nil
 }
 
+// Copy writes the entire database to a writer.
+// A reader transaction is maintained during the copy so it is safe to continue
+// using the database while a copy is in progress.
+func (tx *Tx) Copy(w io.Writer) error {
+
+	// Open reader on the database.
+	f, err := os.Open(tx.db.path)
+	if err != nil {
+		_ = tx.Rollback()
+		return err
+	}
+
+	// Copy the meta pages.
+	tx.db.metalock.Lock()
+	_, err = io.CopyN(w, f, int64(tx.db.pageSize*2))
+	tx.db.metalock.Unlock()
+	if err != nil {
+		_ = tx.Rollback()
+		_ = f.Close()
+		return fmt.Errorf("meta copy: %s", err)
+	}
+
+	// Copy data pages.
+	if _, err := io.Copy(w, f); err != nil {
+		_ = tx.Rollback()
+		_ = f.Close()
+		return err
+	}
+
+	return f.Close()
+}
+
+// CopyFile copies the entire database to file at the given path.
+// A reader transaction is maintained during the copy so it is safe to continue
+// using the database while a copy is in progress.
+func (tx *Tx) CopyFile(path string, mode os.FileMode) error {
+	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, mode)
+	if err != nil {
+		return err
+	}
+
+	err = tx.Copy(f)
+	if err != nil {
+		_ = f.Close()
+		return err
+	}
+	return f.Close()
+}
+
 // Check performs several consistency checks on the database for this transaction.
 // An error is returned if any inconsistency is found or if executed on a read-only transaction.
 func (tx *Tx) Check() error {

tx_test.go

@@ -313,6 +313,31 @@ func TestTx_Check_Corrupt(t *testing.T) {
 	assert.Equal(t, "check fail: 1 errors occurred: page 3: already freed", msg)
 }
 
+// Ensure that the database can be copied to a file path.
+func TestTx_CopyFile(t *testing.T) {
+	withOpenDB(func(db *DB, path string) {
+		var dest = tempfile()
+		db.Update(func(tx *Tx) error {
+			tx.CreateBucket([]byte("widgets"))
+			tx.Bucket([]byte("widgets")).Put([]byte("foo"), []byte("bar"))
+			tx.Bucket([]byte("widgets")).Put([]byte("baz"), []byte("bat"))
+			return nil
+		})
+
+		assert.NoError(t, db.View(func(tx *Tx) error { return tx.CopyFile(dest, 0600) }))
+
+		db2, err := Open(dest, 0600)
+		assert.NoError(t, err)
+		defer db2.Close()
+
+		db2.View(func(tx *Tx) error {
+			assert.Equal(t, []byte("bar"), tx.Bucket([]byte("widgets")).Get([]byte("foo")))
+			assert.Equal(t, []byte("bat"), tx.Bucket([]byte("widgets")).Get([]byte("baz")))
+			return nil
+		})
+	})
+}
+
 func ExampleTx_Rollback() {
 	// Open the database.
 	db, _ := Open(tempfile(), 0666)
@@ -346,3 +371,36 @@ func ExampleTx_Rollback() {
 	// Output:
 	// The value for 'foo' is still: bar
 }
+
+func ExampleTx_CopyFile() {
+	// Open the database.
+	db, _ := Open(tempfile(), 0666)
+	defer os.Remove(db.Path())
+	defer db.Close()
+
+	// Create a bucket and a key.
+	db.Update(func(tx *Tx) error {
+		tx.CreateBucket([]byte("widgets"))
+		tx.Bucket([]byte("widgets")).Put([]byte("foo"), []byte("bar"))
+		return nil
+	})
+
+	// Copy the database to another file.
+	toFile := tempfile()
+	db.View(func(tx *Tx) error { return tx.CopyFile(toFile, 0666) })
+	defer os.Remove(toFile)
+
+	// Open the cloned database.
+	db2, _ := Open(toFile, 0666)
+	defer db2.Close()
+
+	// Ensure that the key exists in the copy.
+	db2.View(func(tx *Tx) error {
+		value := tx.Bucket([]byte("widgets")).Get([]byte("foo"))
+		fmt.Printf("The value for 'foo' in the clone is: %s\n", value)
+		return nil
+	})
+
+	// Output:
+	// The value for 'foo' in the clone is: bar
+}