Improve doc comments.

cache.go

@@ -86,7 +86,7 @@ func (c *cache) flush() {
 
 // CacheSize returns (current, max) sizes.
 // Prepared statements cache is turned off when max size is 0
-func (c *Conn) CacheSize() (int, int) {
+func (c *Conn) CacheSize() (current int, max int) {
 	if c.stmtCache.maxSize <= 0 {
 		return 0, 0
 	}

function.go

@@ -284,14 +284,14 @@ func (c *FunctionContext) Bool(i int) bool {
 // Blob obtains a SQL function parameter value.
 // The leftmost value is number 0.
 // (See sqlite3_value_blob and sqlite3_value_bytes, http://sqlite.org/c3ref/value_blob.html)
-func (c *FunctionContext) Blob(i int) (value []byte) {
+func (c *FunctionContext) Blob(i int) []byte {
 	p := C.my_value_blob(c.argv, C.int(i))
-	if p != nil {
-		n := C.my_value_bytes(c.argv, C.int(i))
-		// value = (*[1 << 30]byte)(unsafe.Pointer(p))[:n]
-		value = C.GoBytes(p, n) // The memory space used to hold strings and BLOBs is freed automatically.
+	if p == nil {
+		return nil
 	}
-	return
+	n := C.my_value_bytes(c.argv, C.int(i))
+	// value = (*[1 << 30]byte)(unsafe.Pointer(p))[:n]
+	return C.GoBytes(p, n) // The memory space used to hold strings and BLOBs is freed automatically.
 }
 
 // Double obtains a SQL function parameter value.
@@ -342,7 +342,8 @@ func (c *FunctionContext) NumericType(i int) Type {
 }
 
 // Value obtains a SQL function parameter value depending on its type.
-func (c *FunctionContext) Value(i int) (value interface{}) {
+func (c *FunctionContext) Value(i int) interface{} {
+	var value interface{}
 	switch c.Type(i) {
 	case Null:
 		value = nil
@@ -357,7 +358,7 @@ func (c *FunctionContext) Value(i int) (value interface{}) {
 	default:
 		panic("The value type is not one of SQLITE_INTEGER, SQLITE_FLOAT, SQLITE_TEXT, SQLITE_BLOB, or SQLITE_NULL")
 	}
-	return
+	return value
 }
 
 // ScalarFunction is the expected signature of scalar function implemented in Go

hook.go

@@ -20,7 +20,7 @@ import (
 
 // CommitHook is the callback function signature.
 // If the callback on a commit hook function returns true, then the commit is converted into a rollback.
-type CommitHook func(udp interface{}) bool
+type CommitHook func(udp interface{}) (rollback bool)
 
 type sqliteCommitHook struct {
 	f   CommitHook

sqlite.go

@@ -472,14 +472,15 @@ func (c *Conn) Rollback() error {
 // Two errors may be returned: the first is the one returned by the f function,
 // the second is the one returned by begin/commit/rollback.
 // (See http://sqlite.org/tclsqlite.html#transaction)
-func (c *Conn) Transaction(t TransactionType, f func(c *Conn) error) (err error) {
+func (c *Conn) Transaction(t TransactionType, f func(c *Conn) error) error {
+	var err error
 	if c.nTransaction == 0 {
 		err = c.BeginTransaction(t)
 	} else {
 		err = c.Savepoint(strconv.Itoa(int(c.nTransaction)))
 	}
 	if err != nil {
-		return
+		return err
 	}
 	c.nTransaction++
 	defer func() {
@@ -507,7 +508,7 @@ func (c *Conn) Transaction(t TransactionType, f func(c *Conn) error) (err error)
 		}
 	}()
 	err = f(c)
-	return
+	return err
 }
 
 // Savepoint starts a new transaction with a name.

stmt.go

@@ -169,8 +169,8 @@ func (s *Stmt) exec() error {
 // ExecDml is like Exec but returns the number of rows that were changed or inserted or deleted.
 // Don't use it with SELECT or anything that returns data.
 // The Stmt is reset at each call.
-func (s *Stmt) ExecDml(args ...interface{}) (int, error) {
-	err := s.Exec(args...)
+func (s *Stmt) ExecDml(args ...interface{}) (changes int, err error) {
+	err = s.Exec(args...)
 	if err != nil {
 		return -1, err
 	}
@@ -180,7 +180,7 @@ func (s *Stmt) ExecDml(args ...interface{}) (int, error) {
 // Insert is like ExecDml but returns the autoincremented rowid.
 // Don't use it with SELECT or anything that returns data.
 // The Stmt is reset at each call.
-func (s *Stmt) Insert(args ...interface{}) (int64, error) {
+func (s *Stmt) Insert(args ...interface{}) (rowid int64, err error) {
 	n, err := s.ExecDml(args...)
 	if err != nil {
 		return -1, err
@@ -232,10 +232,10 @@ func (s *Stmt) Select(rowCallbackHandler func(s *Stmt) error, args ...interface{
 // Returns false if there is no matching row.
 // No check is done to ensure that no more than one row is returned by the statement.
 // TODO Create a SelectUniqueRow that checks that the row is unique.
-func (s *Stmt) SelectOneRow(args ...interface{}) (bool, error) {
-	if ok, err := s.Next(); err != nil {
+func (s *Stmt) SelectOneRow(args ...interface{}) (found bool, err error) {
+	if found, err = s.Next(); err != nil {
 		return false, err
-	} else if !ok {
+	} else if !found {
 		if s.ColumnCount() == 0 {
 			return false, s.specificError("don't use SelectOneRow with query that returns no data such as %q", s.SQL())
 		}
@@ -628,7 +628,7 @@ func (s *Stmt) ColumnIndex(name string) (int, error) {
 // Returns true when column is null.
 // Calls sqlite3_column_(blob|double|int|int64|text) depending on arg type/kind.
 // (See http://sqlite.org/c3ref/column_blob.html)
-func (s *Stmt) ScanByName(name string, value interface{}) (bool, error) {
+func (s *Stmt) ScanByName(name string, value interface{}) (isNull bool, err error) {
 	index, err := s.ColumnIndex(name)
 	if err != nil {
 		return false, err
@@ -654,9 +654,7 @@ func (s *Stmt) ScanByName(name string, value interface{}) (bool, error) {
 // Returns true when column is null.
 // Calls sqlite3_column_(blob|double|int|int64|text) depending on arg type/kind.
 // (See http://sqlite.org/c3ref/column_blob.html)
-func (s *Stmt) ScanByIndex(index int, value interface{}) (bool, error) {
-	var isNull bool
-	var err error
+func (s *Stmt) ScanByIndex(index int, value interface{}) (isNull bool, err error) {
 	switch value := value.(type) {
 	case nil:
 	case *string:
@@ -762,7 +760,7 @@ func (s *Stmt) ScanByIndex(index int, value interface{}) (bool, error) {
 	default:
 		return s.ScanReflect(index, value)
 	}
-	return isNull, err
+	return
 }
 
 // ScanReflect scans result value from a query.
@@ -777,13 +775,11 @@ func (s *Stmt) ScanByIndex(index int, value interface{}) (bool, error) {
 //    *float32,float64
 //
 // Returns true when column is null.
-func (s *Stmt) ScanReflect(index int, v interface{}) (bool, error) {
+func (s *Stmt) ScanReflect(index int, v interface{}) (isNull bool, err error) {
 	rv := reflect.ValueOf(v)
 	if rv.Kind() != reflect.Ptr || rv.IsNil() {
 		return false, s.specificError("ScanReflect unsupported type %T", v)
 	}
-	var isNull bool
-	var err error
 	dv := reflect.Indirect(rv)
 	switch dv.Kind() {
 	case reflect.String:
@@ -821,7 +817,7 @@ func (s *Stmt) ScanReflect(index int, v interface{}) (bool, error) {
 	default:
 		return false, s.specificError("unsupported type in Scan: %T", v)
 	}
-	return isNull, err
+	return
 }
 
 // ScanValue scans result value from a query.
@@ -837,7 +833,7 @@ func (s *Stmt) ScanReflect(index int, v interface{}) (bool, error) {
 //
 // Calls sqlite3_column_(blob|double|int|int64|text) depending on columns type.
 // (See http://sqlite.org/c3ref/column_blob.html)
-func (s *Stmt) ScanValue(index int, blob bool) (interface{}, bool) {
+func (s *Stmt) ScanValue(index int, blob bool) (value interface{}, isNull bool) {
 	switch s.ColumnType(index) {
 	case Null:
 		return nil, true

trace.go

@@ -269,7 +269,7 @@ func (c *Conn) BusyHandler(f BusyHandler, udp interface{}) error {
 // ProgressHandler is the signature of query progress callback.
 // Returns true to interrupt.
 // See Conn.ProgressHandler
-type ProgressHandler func(udp interface{}) bool
+type ProgressHandler func(udp interface{}) (interrupt bool)
 
 type sqliteProgressHandler struct {
 	f   ProgressHandler