Allow custom functions to return nonzero BLOB

func.go

@@ -72,6 +72,9 @@ func (ctx Context) ResultFloat(v float64) { C.sqlite3_result_double(ctx.ptr, C.
 func (ctx Context) ResultNull() { C.sqlite3_result_null(ctx.ptr) }
 func (ctx Context) ResultValue(v Value) { C.sqlite3_result_value(ctx.ptr, v.ptr) }
 func (ctx Context) ResultZeroBlob(n int64) { C.sqlite3_result_zeroblob64(ctx.ptr, C.sqlite3_uint64(n)) }
+func (ctx Context) ResultBlob(v []byte) {
+ C.sqlite3_result_blob(ctx.ptr, C.CBytes(v), C.int(len(v)), (*[0]byte)(C.cfree))
+}
 func (ctx Context) ResultText(v string) {
  var cv *C.char
  if len(v) != 0 {

func_test.go

@@ -15,6 +15,9 @@
 package sqlite_test
 
 import (
+ "bytes"
+ "errors"
+ "strings"
  "testing"
 
  "crawshaw.io/sqlite"
@@ -123,3 +126,114 @@ func TestAggFunc(t *testing.T) {
  }
  stmt.Finalize()
 }
+
+func TestBlobFunc(t *testing.T) {
+ c, err := sqlite.OpenConn(":memory:", 0)
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer func() {
+ if err := c.Close(); err != nil {
+ t.Error(err)
+ }
+ }()
+
+ xFunc := func(ctx sqlite.Context, values ...sqlite.Value) {
+ var buf bytes.Buffer
+ for _, v := range values {
+ buf.Write(v.Blob())
+ }
+ ctx.ResultBlob(buf.Bytes())
+ }
+ if err := c.CreateFunction("blobcat", true, -1, xFunc, nil, nil); err != nil {
+ t.Fatal(err)
+ }
+
+ stmt, _, err := c.PrepareTransient("SELECT blobcat(x'ff00',x'00ba');")
+ if err != nil {
+ t.Fatal(err)
+ }
+ if _, err := stmt.Step(); err != nil {
+ t.Fatal(err)
+ }
+ got := make([]byte, 4)
+ want := []byte{0xFF, 0x00, 0x00, 0xBA}
+ if stmt.ColumnBytes(0, got) != len(want) || !bytes.Equal(got, want) {
+ t.Errorf("blobcat(x'ff00',x'00ba')='%x', want '%x'", got, want)
+ }
+ stmt.Finalize()
+}
+
+func TestStringFunc(t *testing.T) {
+ c, err := sqlite.OpenConn(":memory:", 0)
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer func() {
+ if err := c.Close(); err != nil {
+ t.Error(err)
+ }
+ }()
+
+ xFunc := func(ctx sqlite.Context, values ...sqlite.Value) {
+ var buf strings.Builder
+ for _, v := range values {
+ buf.WriteString(v.Text())
+ }
+ ctx.ResultText(buf.String())
+ }
+ if err := c.CreateFunction("strcat", true, -1, xFunc, nil, nil); err != nil {
+ t.Fatal(err)
+ }
+
+ stmt, _, err := c.PrepareTransient("SELECT strcat('str','','cat');")
+ if err != nil {
+ t.Fatal(err)
+ }
+ if _, err := stmt.Step(); err != nil {
+ t.Fatal(err)
+ }
+ if got, want := stmt.ColumnText(0), "strcat"; got != want {
+ t.Errorf("strcat('str','','cat')='%s', want '%s'", got, want)
+ }
+ stmt.Finalize()
+}
+
+func TestErrorFunc(t *testing.T) {
+ c, err := sqlite.OpenConn(":memory:", 0)
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer func() {
+ if err := c.Close(); err != nil {
+ t.Error(err)
+ }
+ }()
+
+ nilValueError := errors.New("nil value encountered")
+ xFunc := func(ctx sqlite.Context, values ...sqlite.Value) {
+ if values[0].Type() == sqlite.SQLITE_NULL {
+ ctx.ResultError(nilValueError)
+ } else {
+ ctx.ResultValue(values[0])
+ }
+ }
+
+ if err := c.CreateFunction("rejectnull", true, 1, xFunc, nil, nil); err != nil {
+ t.Fatal(err)
+ }
+ stmt, _, err := c.PrepareTransient("SELECT rejectnull(NULL);")
+ if err != nil {
+ t.Fatal(err)
+ }
+
+ _, err = stmt.Step()
+ if err == nil {
+ t.Fatal("rejectnull(NULL) failed to produce an error")
+ }
+ if sqlErr, ok := err.(sqlite.Error); !ok || sqlErr.Msg != nilValueError.Error() {
+ t.Fatal("Error does not match expected description")
+ }
+
+ stmt.Finalize()
+}