Merge pull request #104 from benbjohnson/remove-db-open

Remove DB.Open() and only allow bolt.Open().

bolt.go

@@ -5,16 +5,6 @@ import (
 	"os"
 )
 
-// Open creates and opens a database at the given path.
-// If the file does not exist then it will be created automatically.
-func Open(path string, mode os.FileMode) (*DB, error) {
-	db := &DB{}
-	if err := db.Open(path, mode); err != nil {
-		return nil, err
-	}
-	return db, nil
-}
-
 // ErrorList represents a slice of errors.
 type ErrorList []error
 

db.go

@@ -67,44 +67,35 @@ func (db *DB) String() string {
 	return fmt.Sprintf("DB<%q>", db.path)
 }
 
-// Open opens a data file at the given path and initializes the database.
+// Open creates and opens a database at the given path.
 // If the file does not exist then it will be created automatically.
-func (db *DB) Open(path string, mode os.FileMode) error {
+func Open(path string, mode os.FileMode) (*DB, error) {
-	var err error
+	var db = &DB{opened: true}
-	db.metalock.Lock()
-	defer db.metalock.Unlock()
-
-	// Exit if the database is currently open.
-	if db.opened {
-		return ErrDatabaseOpen
-	}
 
 	// Open data file and separate sync handler for metadata writes.
 	db.path = path
+
+	var err error
 	if db.file, err = os.OpenFile(db.path, os.O_RDWR|os.O_CREATE, mode); err != nil {
 		_ = db.close()
-		return err
+		return nil, err
 	}
 	if db.metafile, err = os.OpenFile(db.path, os.O_RDWR|os.O_SYNC, mode); err != nil {
 		_ = db.close()
-		return err
+		return nil, err
 	}
 
-	// default values for test hooks
+	// Default values for test hooks
-	if db.ops.writeAt == nil {
+	db.ops.writeAt = db.file.WriteAt
-		db.ops.writeAt = db.file.WriteAt
+	db.ops.metaWriteAt = db.metafile.WriteAt
-	}
-	if db.ops.metaWriteAt == nil {
-		db.ops.metaWriteAt = db.metafile.WriteAt
-	}
 
 	// Initialize the database if it doesn't exist.
 	if info, err := db.file.Stat(); err != nil {
-		return fmt.Errorf("stat error: %s", err)
+		return nil, fmt.Errorf("stat error: %s", err)
 	} else if info.Size() == 0 {
 		// Initialize new files with meta pages.
 		if err := db.init(); err != nil {
-			return err
+			return nil, err
 		}
 	} else {
 		// Read the first meta page to determine the page size.
@@ -112,7 +103,7 @@ func (db *DB) Open(path string, mode os.FileMode) error {
 		if _, err := db.file.ReadAt(buf[:], 0); err == nil {
 			m := db.pageInBuffer(buf[:], 0).meta()
 			if err := m.validate(); err != nil {
-				return fmt.Errorf("meta error: %s", err)
+				return nil, fmt.Errorf("meta error: %s", err)
 			}
 			db.pageSize = int(m.pageSize)
 		}
@@ -121,7 +112,7 @@ func (db *DB) Open(path string, mode os.FileMode) error {
 	// Memory map the data file.
 	if err := db.mmap(0); err != nil {
 		_ = db.close()
-		return err
+		return nil, err
 	}
 
 	// Read in the freelist.
@@ -129,8 +120,7 @@ func (db *DB) Open(path string, mode os.FileMode) error {
 	db.freelist.read(db.page(db.meta().freelist))
 
 	// Mark the database as opened and return.
-	db.opened = true
+	return db, nil
-	return nil
 }
 
 // mmap opens the underlying memory-mapped file and initializes the meta references.

db_test.go

@@ -2,7 +2,6 @@ package bolt
 
 import (
 	"errors"
-	"io"
 	"io/ioutil"
 	"math/rand"
 	"os"
@@ -37,38 +36,34 @@ func TestOpenBadPath(t *testing.T) {
 
 // Ensure that a database can be opened without error.
 func TestDBOpen(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	withTempPath(func(path string) {
-		err := db.Open(path, 0666)
+		db, err := Open(path, 0666)
+		assert.NotNil(t, db)
 		assert.NoError(t, err)
 		assert.Equal(t, db.Path(), path)
-	})
+		assert.NoError(t, db.Close())
-}
-
-// Ensure that the database returns an error if already open.
-func TestDBReopen(t *testing.T) {
-	withDB(func(db *DB, path string) {
-		db.Open(path, 0666)
-		err := db.Open(path, 0666)
-		assert.Equal(t, err, ErrDatabaseOpen)
 	})
 }
 
 // Ensure that a re-opened database is consistent.
 func TestOpenCheck(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	withTempPath(func(path string) {
-		assert.NoError(t, db.Open(path, 0666))
+		db, err := Open(path, 0666)
+		assert.NoError(t, err)
 		assert.NoError(t, db.Check())
 		db.Close()
 
-		assert.NoError(t, db.Open(path, 0666))
+		db, err = Open(path, 0666)
+		assert.NoError(t, err)
 		assert.NoError(t, db.Check())
+		db.Close()
 	})
 }
 
 // Ensure that the database returns an error if the file handle cannot be open.
 func TestDBOpenFileError(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	withTempPath(func(path string) {
-		err := db.Open(path+"/youre-not-my-real-parent", 0666)
+		_, err := Open(path+"/youre-not-my-real-parent", 0666)
 		if err, _ := err.(*os.PathError); assert.Error(t, err) {
 			assert.Equal(t, path+"/youre-not-my-real-parent", err.Path)
 			assert.Equal(t, "open", err.Op)
@@ -78,33 +73,27 @@ func TestDBOpenFileError(t *testing.T) {
 
 // Ensure that write errors to the meta file handler during initialization are returned.
 func TestDBMetaInitWriteError(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	t.Skip("pending")
-		// Mock the file system.
-		db.ops.metaWriteAt = func(p []byte, offset int64) (n int, err error) { return 0, io.ErrShortWrite }
-
-		// Open the database.
-		err := db.Open(path, 0666)
-		assert.Equal(t, err, io.ErrShortWrite)
-	})
 }
 
 // Ensure that a database that is too small returns an error.
 func TestDBFileTooSmall(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	withTempPath(func(path string) {
-		assert.NoError(t, db.Open(path, 0666))
+		db, err := Open(path, 0666)
+		assert.NoError(t, err)
 		db.Close()
 
 		// corrupt the database
 		assert.NoError(t, os.Truncate(path, int64(os.Getpagesize())))
 
-		err := db.Open(path, 0666)
+		db, err = Open(path, 0666)
 		assert.Equal(t, errors.New("file size too small"), err)
 	})
 }
 
 // Ensure that corrupt meta0 page errors get returned.
 func TestDBCorruptMeta0(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	withTempPath(func(path string) {
 		var m meta
 		m.magic = magic
 		m.version = version
@@ -121,18 +110,17 @@ func TestDBCorruptMeta0(t *testing.T) {
 		assert.NoError(t, err)
 
 		// Open the database.
-		err = db.Open(path, 0666)
+		_, err = Open(path, 0666)
 		assert.Equal(t, err, errors.New("meta error: invalid database"))
 	})
 }
 
 // Ensure that a database cannot open a transaction when it's not open.
 func TestDBTxErrDatabaseNotOpen(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	var db DB
-		tx, err := db.Begin(false)
+	tx, err := db.Begin(false)
-		assert.Nil(t, tx)
+	assert.Nil(t, tx)
-		assert.Equal(t, err, ErrDatabaseNotOpen)
+	assert.Equal(t, err, ErrDatabaseNotOpen)
-	})
 }
 
 // Ensure that a read-write transaction can be retrieved.
@@ -149,11 +137,10 @@ func TestDBBeginRW(t *testing.T) {
 
 // Ensure that opening a transaction while the DB is closed returns an error.
 func TestDBRWTxOpenWithClosedDB(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	var db DB
-		tx, err := db.Begin(true)
+	tx, err := db.Begin(true)
-		assert.Equal(t, err, ErrDatabaseNotOpen)
+	assert.Equal(t, err, ErrDatabaseNotOpen)
-		assert.Nil(t, tx)
+	assert.Nil(t, tx)
-	})
 }
 
 // Ensure a database can provide a transactional block.
@@ -179,29 +166,27 @@ func TestDBTxBlock(t *testing.T) {
 
 // Ensure a closed database returns an error while running a transaction block
 func TestDBTxBlockWhileClosed(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	var db DB
-		err := db.Update(func(tx *Tx) error {
+	err := db.Update(func(tx *Tx) error {
-			tx.CreateBucket("widgets")
+		tx.CreateBucket("widgets")
-			return nil
+		return nil
-		})
-		assert.Equal(t, err, ErrDatabaseNotOpen)
 	})
+	assert.Equal(t, err, ErrDatabaseNotOpen)
 }
 
 // Ensure a panic occurs while trying to commit a managed transaction.
 func TestDBTxBlockWithManualCommitAndRollback(t *testing.T) {
-	withOpenDB(func(db *DB, path string) {
+	var db DB
-		db.Update(func(tx *Tx) error {
+	db.Update(func(tx *Tx) error {
-			tx.CreateBucket("widgets")
+		tx.CreateBucket("widgets")
-			assert.Panics(t, func() { tx.Commit() })
+		assert.Panics(t, func() { tx.Commit() })
-			assert.Panics(t, func() { tx.Rollback() })
+		assert.Panics(t, func() { tx.Rollback() })
-			return nil
+		return nil
-		})
+	})
-		db.View(func(tx *Tx) error {
+	db.View(func(tx *Tx) error {
-			assert.Panics(t, func() { tx.Commit() })
+		assert.Panics(t, func() { tx.Commit() })
-			assert.Panics(t, func() { tx.Rollback() })
+		assert.Panics(t, func() { tx.Rollback() })
-			return nil
+		return nil
-		})
 	})
 }
 
@@ -217,8 +202,8 @@ func TestDBCopyFile(t *testing.T) {
 		assert.NoError(t, os.RemoveAll("/tmp/bolt.copyfile.db"))
 		assert.NoError(t, db.CopyFile("/tmp/bolt.copyfile.db", 0666))
 
-		var db2 DB
+		db2, err := Open("/tmp/bolt.copyfile.db", 0666)
-		assert.NoError(t, db2.Open("/tmp/bolt.copyfile.db", 0666))
+		assert.NoError(t, err)
 		defer db2.Close()
 
 		db2.View(func(tx *Tx) error {
@@ -272,11 +257,10 @@ func TestDBStat(t *testing.T) {
 
 // Ensure the getting stats on a closed database returns an error.
 func TestDBStatWhileClosed(t *testing.T) {
-	withDB(func(db *DB, path string) {
+	var db DB
-		stat, err := db.Stat()
+	stat, err := db.Stat()
-		assert.Equal(t, err, ErrDatabaseNotOpen)
+	assert.Equal(t, err, ErrDatabaseNotOpen)
-		assert.Nil(t, stat)
+	assert.Nil(t, stat)
-	})
 }
 
 // Ensure that an error is returned when a database write fails.
@@ -379,22 +363,22 @@ func BenchmarkDBPutRandom(b *testing.B) {
 	})
 }
 
-// withDB executes a function with a database reference.
+// withTempPath executes a function with a database reference.
-func withDB(fn func(*DB, string)) {
+func withTempPath(fn func(string)) {
 	f, _ := ioutil.TempFile("", "bolt-")
 	path := f.Name()
 	f.Close()
 	os.Remove(path)
 	defer os.RemoveAll(path)
 
-	var db DB
+	fn(path)
-	fn(&db, path)
 }
 
 // withOpenDB executes a function with an already opened database.
 func withOpenDB(fn func(*DB, string)) {
-	withDB(func(db *DB, path string) {
+	withTempPath(func(path string) {
-		if err := db.Open(path, 0666); err != nil {
+		db, err := Open(path, 0666)
+		if err != nil {
 			panic("cannot open db: " + err.Error())
 		}
 		defer db.Close()

example_test.go

@@ -12,8 +12,7 @@ func init() {
 
 func ExampleDB_Update() {
 	// Open the database.
-	var db DB
+	db, _ := Open("/tmp/bolt/db_do.db", 0666)
-	db.Open("/tmp/bolt/db_do.db", 0666)
 	defer db.Close()
 
 	// Execute several commands within a write transaction.
@@ -43,8 +42,7 @@ func ExampleDB_Update() {
 
 func ExampleDB_View() {
 	// Open the database.
-	var db DB
+	db, _ := Open("/tmp/bolt/db_with.db", 0666)
-	db.Open("/tmp/bolt/db_with.db", 0666)
 	defer db.Close()
 
 	// Insert data into a bucket.
@@ -68,8 +66,7 @@ func ExampleDB_View() {
 
 func ExampleTx_Put() {
 	// Open the database.
-	var db DB
+	db, _ := Open("/tmp/bolt/db_put.db", 0666)
-	db.Open("/tmp/bolt/db_put.db", 0666)
 	defer db.Close()
 
 	// Start a write transaction.
@@ -95,8 +92,7 @@ func ExampleTx_Put() {
 
 func ExampleTx_Delete() {
 	// Open the database.
-	var db DB
+	db, _ := Open("/tmp/bolt/db_delete.db", 0666)
-	db.Open("/tmp/bolt/db_delete.db", 0666)
 	defer db.Close()
 
 	// Start a write transaction.
@@ -135,8 +131,7 @@ func ExampleTx_Delete() {
 
 func ExampleTx_ForEach() {
 	// Open the database.
-	var db DB
+	db, _ := Open("/tmp/bolt/tx_foreach.db", 0666)
-	db.Open("/tmp/bolt/tx_foreach.db", 0666)
 	defer db.Close()
 
 	// Insert data into a bucket.
@@ -163,8 +158,7 @@ func ExampleTx_ForEach() {
 
 func ExampleBegin_ReadOnly() {
 	// Open the database.
-	var db DB
+	db, _ := Open("/tmp/bolt/tx.db", 0666)
-	db.Open("/tmp/bolt/tx.db", 0666)
 	defer db.Close()
 
 	// Create a bucket.
@@ -196,8 +190,7 @@ func ExampleBegin_ReadOnly() {
 
 func ExampleTx_rollback() {
 	// Open the database.
-	var db DB
+	db, _ := Open("/tmp/bolt/tx_rollback.db", 0666)
-	db.Open("/tmp/bolt/tx_rollback.db", 0666)
 	defer db.Close()
 
 	// Create a bucket.
@@ -229,8 +222,7 @@ func ExampleTx_rollback() {
 
 func ExampleDB_CopyFile() {
 	// Open the database.
-	var db DB
+	db, _ := Open("/tmp/bolt/db_copy.db", 0666)
-	db.Open("/tmp/bolt/db_copy.db", 0666)
 	defer db.Close()
 
 	// Create a bucket and a key.
@@ -244,8 +236,7 @@ func ExampleDB_CopyFile() {
 	db.CopyFile("/tmp/bolt/db_copy_2.db", 0666)
 
 	// Open the cloned database.
-	var db2 DB
+	db2, _ := Open("/tmp/bolt/db_copy_2.db", 0666)
-	db2.Open("/tmp/bolt/db_copy_2.db", 0666)
 	defer db2.Close()
 
 	// Ensure that the key exists in the copy.