Merge b4e9f90 into 240ea3c

sqlhooks.go

@@ -3,6 +3,7 @@ package sqlhooks
 import (
 	"context"
 	"database/sql/driver"
+	"errors"
 )
 
 // Hook is the hook callback signature
@@ -27,7 +28,13 @@ func (drv *Driver) Open(name string) (driver.Conn, error) {
 		return conn, err
 	}
 
-	return &Conn{conn, drv.hooks}, nil
+	wrapped := &Conn{conn, drv.hooks}
+	if isExecer(conn) {
+		// If conn implements an Execer interface, return a driver.Conn which
+		// also implements Execer
+		return &ExecerContext{wrapped}, nil
+	}
+	return wrapped, nil
 }
 
 // Conn implements a database/sql.driver.Conn
@@ -59,6 +66,68 @@ func (conn *Conn) Prepare(query string) (driver.Stmt, error) { return conn.Conn.
 func (conn *Conn) Close() error                              { return conn.Conn.Close() }
 func (conn *Conn) Begin() (driver.Tx, error)                 { return conn.Conn.Begin() }
 
+// ExecerContext implements a database/sql.driver.ExecerContext
+type ExecerContext struct {
+	*Conn
+}
+
+func isExecer(conn driver.Conn) bool {
+	switch conn.(type) {
+	case driver.ExecerContext:
+		return true
+	case driver.Execer:
+		return true
+	default:
+		return false
+	}
+}
+
+func (conn *ExecerContext) execContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	switch c := conn.Conn.Conn.(type) {
+	case driver.ExecerContext:
+		return c.ExecContext(ctx, query, args)
+	case driver.Execer:
+		dargs, err := namedValueToValue(args)
+		if err != nil {
+			return nil, err
+		}
+		return c.Exec(query, dargs)
+	default:
+		// This should not happen
+		return nil, errors.New("ExecerContext created for a non Execer driver.Conn")
+	}
+}
+
+func (conn *ExecerContext) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	var err error
+
+	list := namedToInterface(args)
+
+	// Exec `Before` Hooks
+	if ctx, err = conn.hooks.Before(ctx, query, list...); err != nil {
+		return nil, err
+	}
+
+	results, err := conn.execContext(ctx, query, args)
+	if err != nil {
+		return results, err
+	}
+
+	if ctx, err = conn.hooks.After(ctx, query, list...); err != nil {
+		return nil, err
+	}
+
+	return results, err
+}
+
+func (conn *ExecerContext) Exec(query string, args []driver.Value) (driver.Result, error) {
+	// We have to implement Exec since it is required in the current version of
+	// Go for it to run ExecContext. From Go 10 it will be optional. However,
+	// this code should never run since database/sql always prefers to run
+	// ExecContext.
+	return nil, errors.New("Exec was called when ExecContext was implemented")
+}
+
 // Stmt implements a database/sql/driver.Stmt
 type Stmt struct {
 	Stmt  driver.Stmt
@@ -154,6 +223,18 @@ func namedToInterface(args []driver.NamedValue) []interface{} {
 	return list
 }
 
+// namedValueToValue copied from database/sql
+func namedValueToValue(named []driver.NamedValue) ([]driver.Value, error) {
+	dargs := make([]driver.Value, len(named))
+	for n, param := range named {
+		if len(param.Name) > 0 {
+			return nil, errors.New("sql: driver does not support the use of Named Parameters")
+		}
+		dargs[n] = param.Value
+	}
+	return dargs, nil
+}
+
 /*
 type hooks struct {
 }