Retro68/gcc/libgo/go/database/sql/fakedb_test.go

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2012-03-27 23:13:14 +00:00
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package sql
import (
"database/sql/driver"
"errors"
"fmt"
"io"
"log"
"strconv"
"strings"
"sync"
"time"
)
var _ = log.Printf
// fakeDriver is a fake database that implements Go's driver.Driver
// interface, just for testing.
//
// It speaks a query language that's semantically similar to but
// syntantically different and simpler than SQL. The syntax is as
// follows:
//
// WIPE
// CREATE|<tablename>|<col>=<type>,<col>=<type>,...
// where types are: "string", [u]int{8,16,32,64}, "bool"
// INSERT|<tablename>|col=val,col2=val2,col3=?
// SELECT|<tablename>|projectcol1,projectcol2|filtercol=?,filtercol2=?
//
// When opening a a fakeDriver's database, it starts empty with no
// tables. All tables and data are stored in memory only.
type fakeDriver struct {
mu sync.Mutex
openCount int
dbs map[string]*fakeDB
}
type fakeDB struct {
name string
mu sync.Mutex
free []*fakeConn
tables map[string]*table
}
type table struct {
mu sync.Mutex
colname []string
coltype []string
rows []*row
}
func (t *table) columnIndex(name string) int {
for n, nname := range t.colname {
if name == nname {
return n
}
}
return -1
}
type row struct {
cols []interface{} // must be same size as its table colname + coltype
}
func (r *row) clone() *row {
nrow := &row{cols: make([]interface{}, len(r.cols))}
copy(nrow.cols, r.cols)
return nrow
}
type fakeConn struct {
db *fakeDB // where to return ourselves to
currTx *fakeTx
// Stats for tests:
mu sync.Mutex
stmtsMade int
stmtsClosed int
}
func (c *fakeConn) incrStat(v *int) {
c.mu.Lock()
*v++
c.mu.Unlock()
}
type fakeTx struct {
c *fakeConn
}
type fakeStmt struct {
c *fakeConn
q string // just for debugging
cmd string
table string
closed bool
colName []string // used by CREATE, INSERT, SELECT (selected columns)
colType []string // used by CREATE
colValue []interface{} // used by INSERT (mix of strings and "?" for bound params)
placeholders int // used by INSERT/SELECT: number of ? params
whereCol []string // used by SELECT (all placeholders)
placeholderConverter []driver.ValueConverter // used by INSERT
}
var fdriver driver.Driver = &fakeDriver{}
func init() {
Register("test", fdriver)
}
// Supports dsn forms:
// <dbname>
// <dbname>;<opts> (no currently supported options)
func (d *fakeDriver) Open(dsn string) (driver.Conn, error) {
parts := strings.Split(dsn, ";")
if len(parts) < 1 {
return nil, errors.New("fakedb: no database name")
}
name := parts[0]
db := d.getDB(name)
d.mu.Lock()
d.openCount++
d.mu.Unlock()
return &fakeConn{db: db}, nil
}
func (d *fakeDriver) getDB(name string) *fakeDB {
d.mu.Lock()
defer d.mu.Unlock()
if d.dbs == nil {
d.dbs = make(map[string]*fakeDB)
}
db, ok := d.dbs[name]
if !ok {
db = &fakeDB{name: name}
d.dbs[name] = db
}
return db
}
func (db *fakeDB) wipe() {
db.mu.Lock()
defer db.mu.Unlock()
db.tables = nil
}
func (db *fakeDB) createTable(name string, columnNames, columnTypes []string) error {
db.mu.Lock()
defer db.mu.Unlock()
if db.tables == nil {
db.tables = make(map[string]*table)
}
if _, exist := db.tables[name]; exist {
return fmt.Errorf("table %q already exists", name)
}
if len(columnNames) != len(columnTypes) {
return fmt.Errorf("create table of %q len(names) != len(types): %d vs %d",
name, len(columnNames), len(columnTypes))
}
db.tables[name] = &table{colname: columnNames, coltype: columnTypes}
return nil
}
// must be called with db.mu lock held
func (db *fakeDB) table(table string) (*table, bool) {
if db.tables == nil {
return nil, false
}
t, ok := db.tables[table]
return t, ok
}
func (db *fakeDB) columnType(table, column string) (typ string, ok bool) {
db.mu.Lock()
defer db.mu.Unlock()
t, ok := db.table(table)
if !ok {
return
}
for n, cname := range t.colname {
if cname == column {
return t.coltype[n], true
}
}
return "", false
}
func (c *fakeConn) Begin() (driver.Tx, error) {
if c.currTx != nil {
return nil, errors.New("already in a transaction")
}
c.currTx = &fakeTx{c: c}
return c.currTx, nil
}
func (c *fakeConn) Close() error {
if c.currTx != nil {
return errors.New("can't close; in a Transaction")
}
if c.db == nil {
return errors.New("can't close; already closed")
}
c.db = nil
return nil
}
func checkSubsetTypes(args []driver.Value) error {
for n, arg := range args {
switch arg.(type) {
case int64, float64, bool, nil, []byte, string, time.Time:
default:
return fmt.Errorf("fakedb_test: invalid argument #%d: %v, type %T", n+1, arg, arg)
}
}
return nil
}
func (c *fakeConn) Exec(query string, args []driver.Value) (driver.Result, error) {
// This is an optional interface, but it's implemented here
// just to check that all the args of of the proper types.
// ErrSkip is returned so the caller acts as if we didn't
// implement this at all.
err := checkSubsetTypes(args)
if err != nil {
return nil, err
}
return nil, driver.ErrSkip
}
func errf(msg string, args ...interface{}) error {
return errors.New("fakedb: " + fmt.Sprintf(msg, args...))
}
// parts are table|selectCol1,selectCol2|whereCol=?,whereCol2=?
// (note that where where columns must always contain ? marks,
// just a limitation for fakedb)
func (c *fakeConn) prepareSelect(stmt *fakeStmt, parts []string) (driver.Stmt, error) {
if len(parts) != 3 {
return nil, errf("invalid SELECT syntax with %d parts; want 3", len(parts))
}
stmt.table = parts[0]
stmt.colName = strings.Split(parts[1], ",")
for n, colspec := range strings.Split(parts[2], ",") {
if colspec == "" {
continue
}
nameVal := strings.Split(colspec, "=")
if len(nameVal) != 2 {
return nil, errf("SELECT on table %q has invalid column spec of %q (index %d)", stmt.table, colspec, n)
}
column, value := nameVal[0], nameVal[1]
_, ok := c.db.columnType(stmt.table, column)
if !ok {
return nil, errf("SELECT on table %q references non-existent column %q", stmt.table, column)
}
if value != "?" {
return nil, errf("SELECT on table %q has pre-bound value for where column %q; need a question mark",
stmt.table, column)
}
stmt.whereCol = append(stmt.whereCol, column)
stmt.placeholders++
}
return stmt, nil
}
// parts are table|col=type,col2=type2
func (c *fakeConn) prepareCreate(stmt *fakeStmt, parts []string) (driver.Stmt, error) {
if len(parts) != 2 {
return nil, errf("invalid CREATE syntax with %d parts; want 2", len(parts))
}
stmt.table = parts[0]
for n, colspec := range strings.Split(parts[1], ",") {
nameType := strings.Split(colspec, "=")
if len(nameType) != 2 {
return nil, errf("CREATE table %q has invalid column spec of %q (index %d)", stmt.table, colspec, n)
}
stmt.colName = append(stmt.colName, nameType[0])
stmt.colType = append(stmt.colType, nameType[1])
}
return stmt, nil
}
// parts are table|col=?,col2=val
func (c *fakeConn) prepareInsert(stmt *fakeStmt, parts []string) (driver.Stmt, error) {
if len(parts) != 2 {
return nil, errf("invalid INSERT syntax with %d parts; want 2", len(parts))
}
stmt.table = parts[0]
for n, colspec := range strings.Split(parts[1], ",") {
nameVal := strings.Split(colspec, "=")
if len(nameVal) != 2 {
return nil, errf("INSERT table %q has invalid column spec of %q (index %d)", stmt.table, colspec, n)
}
column, value := nameVal[0], nameVal[1]
ctype, ok := c.db.columnType(stmt.table, column)
if !ok {
return nil, errf("INSERT table %q references non-existent column %q", stmt.table, column)
}
stmt.colName = append(stmt.colName, column)
if value != "?" {
var subsetVal interface{}
// Convert to driver subset type
switch ctype {
case "string":
subsetVal = []byte(value)
case "blob":
subsetVal = []byte(value)
case "int32":
i, err := strconv.Atoi(value)
if err != nil {
return nil, errf("invalid conversion to int32 from %q", value)
}
subsetVal = int64(i) // int64 is a subset type, but not int32
default:
return nil, errf("unsupported conversion for pre-bound parameter %q to type %q", value, ctype)
}
stmt.colValue = append(stmt.colValue, subsetVal)
} else {
stmt.placeholders++
stmt.placeholderConverter = append(stmt.placeholderConverter, converterForType(ctype))
stmt.colValue = append(stmt.colValue, "?")
}
}
return stmt, nil
}
func (c *fakeConn) Prepare(query string) (driver.Stmt, error) {
if c.db == nil {
panic("nil c.db; conn = " + fmt.Sprintf("%#v", c))
}
parts := strings.Split(query, "|")
if len(parts) < 1 {
return nil, errf("empty query")
}
cmd := parts[0]
parts = parts[1:]
stmt := &fakeStmt{q: query, c: c, cmd: cmd}
c.incrStat(&c.stmtsMade)
switch cmd {
case "WIPE":
// Nothing
case "SELECT":
return c.prepareSelect(stmt, parts)
case "CREATE":
return c.prepareCreate(stmt, parts)
case "INSERT":
return c.prepareInsert(stmt, parts)
default:
return nil, errf("unsupported command type %q", cmd)
}
return stmt, nil
}
func (s *fakeStmt) ColumnConverter(idx int) driver.ValueConverter {
return s.placeholderConverter[idx]
}
func (s *fakeStmt) Close() error {
if !s.closed {
s.c.incrStat(&s.c.stmtsClosed)
s.closed = true
}
return nil
}
var errClosed = errors.New("fakedb: statement has been closed")
func (s *fakeStmt) Exec(args []driver.Value) (driver.Result, error) {
if s.closed {
return nil, errClosed
}
err := checkSubsetTypes(args)
if err != nil {
return nil, err
}
db := s.c.db
switch s.cmd {
case "WIPE":
db.wipe()
return driver.ResultNoRows, nil
case "CREATE":
if err := db.createTable(s.table, s.colName, s.colType); err != nil {
return nil, err
}
return driver.ResultNoRows, nil
case "INSERT":
return s.execInsert(args)
}
fmt.Printf("EXEC statement, cmd=%q: %#v\n", s.cmd, s)
return nil, fmt.Errorf("unimplemented statement Exec command type of %q", s.cmd)
}
func (s *fakeStmt) execInsert(args []driver.Value) (driver.Result, error) {
db := s.c.db
if len(args) != s.placeholders {
panic("error in pkg db; should only get here if size is correct")
}
db.mu.Lock()
t, ok := db.table(s.table)
db.mu.Unlock()
if !ok {
return nil, fmt.Errorf("fakedb: table %q doesn't exist", s.table)
}
t.mu.Lock()
defer t.mu.Unlock()
cols := make([]interface{}, len(t.colname))
argPos := 0
for n, colname := range s.colName {
colidx := t.columnIndex(colname)
if colidx == -1 {
return nil, fmt.Errorf("fakedb: column %q doesn't exist or dropped since prepared statement was created", colname)
}
var val interface{}
if strvalue, ok := s.colValue[n].(string); ok && strvalue == "?" {
val = args[argPos]
argPos++
} else {
val = s.colValue[n]
}
cols[colidx] = val
}
t.rows = append(t.rows, &row{cols: cols})
return driver.RowsAffected(1), nil
}
func (s *fakeStmt) Query(args []driver.Value) (driver.Rows, error) {
if s.closed {
return nil, errClosed
}
err := checkSubsetTypes(args)
if err != nil {
return nil, err
}
db := s.c.db
if len(args) != s.placeholders {
panic("error in pkg db; should only get here if size is correct")
}
db.mu.Lock()
t, ok := db.table(s.table)
db.mu.Unlock()
if !ok {
return nil, fmt.Errorf("fakedb: table %q doesn't exist", s.table)
}
t.mu.Lock()
defer t.mu.Unlock()
colIdx := make(map[string]int) // select column name -> column index in table
for _, name := range s.colName {
idx := t.columnIndex(name)
if idx == -1 {
return nil, fmt.Errorf("fakedb: unknown column name %q", name)
}
colIdx[name] = idx
}
mrows := []*row{}
rows:
for _, trow := range t.rows {
// Process the where clause, skipping non-match rows. This is lazy
// and just uses fmt.Sprintf("%v") to test equality. Good enough
// for test code.
for widx, wcol := range s.whereCol {
idx := t.columnIndex(wcol)
if idx == -1 {
return nil, fmt.Errorf("db: invalid where clause column %q", wcol)
}
tcol := trow.cols[idx]
if bs, ok := tcol.([]byte); ok {
// lazy hack to avoid sprintf %v on a []byte
tcol = string(bs)
}
if fmt.Sprintf("%v", tcol) != fmt.Sprintf("%v", args[widx]) {
continue rows
}
}
mrow := &row{cols: make([]interface{}, len(s.colName))}
for seli, name := range s.colName {
mrow.cols[seli] = trow.cols[colIdx[name]]
}
mrows = append(mrows, mrow)
}
cursor := &rowsCursor{
pos: -1,
rows: mrows,
cols: s.colName,
}
return cursor, nil
}
func (s *fakeStmt) NumInput() int {
return s.placeholders
}
func (tx *fakeTx) Commit() error {
tx.c.currTx = nil
return nil
}
func (tx *fakeTx) Rollback() error {
tx.c.currTx = nil
return nil
}
type rowsCursor struct {
cols []string
pos int
rows []*row
closed bool
// a clone of slices to give out to clients, indexed by the
// the original slice's first byte address. we clone them
// just so we're able to corrupt them on close.
bytesClone map[*byte][]byte
}
func (rc *rowsCursor) Close() error {
if !rc.closed {
for _, bs := range rc.bytesClone {
bs[0] = 255 // first byte corrupted
}
}
rc.closed = true
return nil
}
func (rc *rowsCursor) Columns() []string {
return rc.cols
}
func (rc *rowsCursor) Next(dest []driver.Value) error {
if rc.closed {
return errors.New("fakedb: cursor is closed")
}
rc.pos++
if rc.pos >= len(rc.rows) {
return io.EOF // per interface spec
}
for i, v := range rc.rows[rc.pos].cols {
// TODO(bradfitz): convert to subset types? naah, I
// think the subset types should only be input to
// driver, but the sql package should be able to handle
// a wider range of types coming out of drivers. all
// for ease of drivers, and to prevent drivers from
// messing up conversions or doing them differently.
dest[i] = v
if bs, ok := v.([]byte); ok {
if rc.bytesClone == nil {
rc.bytesClone = make(map[*byte][]byte)
}
clone, ok := rc.bytesClone[&bs[0]]
if !ok {
clone = make([]byte, len(bs))
copy(clone, bs)
rc.bytesClone[&bs[0]] = clone
}
dest[i] = clone
}
}
return nil
}
func converterForType(typ string) driver.ValueConverter {
switch typ {
case "bool":
return driver.Bool
case "nullbool":
return driver.Null{Converter: driver.Bool}
case "int32":
return driver.Int32
case "string":
return driver.NotNull{Converter: driver.String}
case "nullstring":
return driver.Null{Converter: driver.String}
case "int64":
// TODO(coopernurse): add type-specific converter
return driver.NotNull{Converter: driver.DefaultParameterConverter}
case "nullint64":
// TODO(coopernurse): add type-specific converter
return driver.Null{Converter: driver.DefaultParameterConverter}
case "float64":
// TODO(coopernurse): add type-specific converter
return driver.NotNull{Converter: driver.DefaultParameterConverter}
case "nullfloat64":
// TODO(coopernurse): add type-specific converter
return driver.Null{Converter: driver.DefaultParameterConverter}
case "datetime":
return driver.DefaultParameterConverter
}
panic("invalid fakedb column type of " + typ)
}