Pablu/go-sqlite3
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Implement support for variadic functions.

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Currently, the variadic part must all be the same type, because there's
no "generic" arg converter.
This commit is contained in:
David Anderson
2015-08-21 16:34:55 -07:00
parent 122ddb16de
commit 566f63a43a
2 changed files with 55 additions and 10 deletions
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52
sqlite3.go
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@@ -165,9 +165,10 @@ type SQLiteRows struct {
}
type functionInfo struct {
f reflect.Value
argConverters []callbackArgConverter
retConverter callbackRetConverter
f reflect.Value
argConverters []callbackArgConverter
variadicConverter callbackArgConverter
retConverter callbackRetConverter
}
func (fi *functionInfo) error(ctx *C.sqlite3_context, err error) {
@@ -178,7 +179,12 @@ func (fi *functionInfo) error(ctx *C.sqlite3_context, err error) {
func (fi *functionInfo) Call(ctx *C.sqlite3_context, argv []*C.sqlite3_value) {
var args []reflect.Value
for i, arg := range argv {
if len(argv) < len(fi.argConverters) {
fi.error(ctx, fmt.Errorf("function requires at least %d arguments", len(fi.argConverters)))
}
for i, arg := range argv[:len(fi.argConverters)] {
v, err := fi.argConverters[i](arg)
if err != nil {
fi.error(ctx, err)
@@ -187,6 +193,17 @@ func (fi *functionInfo) Call(ctx *C.sqlite3_context, argv []*C.sqlite3_value) {
args = append(args, v)
}
if fi.variadicConverter != nil {
for _, arg := range argv[len(fi.argConverters):] {
v, err := fi.variadicConverter(arg)
if err != nil {
fi.error(ctx, err)
return
}
args = append(args, v)
}
}
ret := fi.f.Call(args)
if len(ret) == 2 && ret[1].Interface() != nil {
@@ -218,7 +235,8 @@ func (tx *SQLiteTx) Rollback() error {
// The function can accept arguments of any real numeric type
// (i.e. not complex), as well as []byte and string. It must return a
// value of one of those types, and optionally an error as a second
// value.
// value. Variadic functions are allowed, if the variadic argument is
// one of the allowed types.
//
// If pure is true. SQLite will assume that the function's return
// value depends only on its inputs, and make more aggressive
@@ -230,9 +248,6 @@ func (c *SQLiteConn) RegisterFunc(name string, impl interface{}, pure bool) erro
if t.Kind() != reflect.Func {
return errors.New("Non-function passed to RegisterFunc")
}
if t.IsVariadic() {
return errors.New("Variadic SQLite functions are not supported")
}
if t.NumOut() != 1 && t.NumOut() != 2 {
return errors.New("SQLite functions must return 1 or 2 values")
}
@@ -240,7 +255,12 @@ func (c *SQLiteConn) RegisterFunc(name string, impl interface{}, pure bool) erro
return errors.New("Second return value of SQLite function must be error")
}
for i := 0; i < t.NumIn(); i++ {
numArgs := t.NumIn()
if t.IsVariadic() {
numArgs--
}
for i := 0; i < numArgs; i++ {
conv, err := callbackArg(t.In(i))
if err != nil {
return err
@@ -248,6 +268,18 @@ func (c *SQLiteConn) RegisterFunc(name string, impl interface{}, pure bool) erro
fi.argConverters = append(fi.argConverters, conv)
}
if t.IsVariadic() {
conv, err := callbackArg(t.In(numArgs).Elem())
if err != nil {
return err
}
fi.variadicConverter = conv
// Pass -1 to sqlite so that it allows any number of
// arguments. The call helper verifies that the minimum number
// of arguments is present for variadic functions.
numArgs = -1
}
conv, err := callbackRet(t.Out(0))
if err != nil {
return err
@@ -263,7 +295,7 @@ func (c *SQLiteConn) RegisterFunc(name string, impl interface{}, pure bool) erro
if pure {
opts |= C.SQLITE_DETERMINISTIC
}
rv := C.sqlite3_create_function_v2(c.db, cname, C.int(t.NumIn()), C.int(opts), unsafe.Pointer(&fi), (*[0]byte)(unsafe.Pointer(C.callbackTrampoline)), nil, nil, nil)
rv := C.sqlite3_create_function_v2(c.db, cname, C.int(numArgs), C.int(opts), unsafe.Pointer(&fi), (*[0]byte)(unsafe.Pointer(C.callbackTrampoline)), nil, nil, nil)
if rv != C.SQLITE_OK {
return c.lastError()
}