148 lines
3.7 KiB
Go
148 lines
3.7 KiB
Go
package jen
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import (
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"bytes"
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"fmt"
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"go/format"
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"io"
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)
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// Group represents a list of Code items, separated by tokens with an optional
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// open and close token.
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type Group struct {
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name string
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items []Code
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open string
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close string
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separator string
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multi bool
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}
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func (g *Group) isNull(f *File) bool {
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if g == nil {
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return true
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}
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if g.open != "" || g.close != "" {
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return false
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}
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for _, c := range g.items {
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if !c.isNull(f) {
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return false
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}
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}
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return true
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}
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func (g *Group) render(f *File, w io.Writer, s *Statement) error {
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if g.name == "block" && s != nil {
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// Special CaseBlock format for then the previous item in the statement
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// is a Case group or the default keyword.
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prev := s.previous(g)
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grp, isGrp := prev.(*Group)
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tkn, isTkn := prev.(token)
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if isGrp && grp.name == "case" || isTkn && tkn.content == "default" {
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g.open = ""
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g.close = ""
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}
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}
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if g.open != "" {
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if _, err := w.Write([]byte(g.open)); err != nil {
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return err
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}
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}
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isNull, err := g.renderItems(f, w)
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if err != nil {
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return err
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}
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if !isNull && g.multi && g.close != "" {
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// For multi-line blocks with a closing token, we insert a new line after the last item (but
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// not if all items were null). This is to ensure that if the statement finishes with a comment,
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// the closing token is not commented out.
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s := "\n"
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if g.separator == "," {
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// We also insert add trailing comma if the separator was ",".
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s = ",\n"
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}
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if _, err := w.Write([]byte(s)); err != nil {
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return err
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}
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}
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if g.close != "" {
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if _, err := w.Write([]byte(g.close)); err != nil {
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return err
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}
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}
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return nil
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}
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func (g *Group) renderItems(f *File, w io.Writer) (isNull bool, err error) {
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first := true
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for _, code := range g.items {
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if pt, ok := code.(token); ok && pt.typ == packageToken {
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// Special case for package tokens in Qual groups - for dot-imports, the package token
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// will be null, so will not render and will not be registered in the imports block.
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// This ensures all packageTokens that are rendered are registered.
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f.register(pt.content.(string))
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}
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if code == nil || code.isNull(f) {
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// Null() token produces no output but also
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// no separator. Empty() token products no
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// output but adds a separator.
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continue
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}
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if g.name == "values" {
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if _, ok := code.(Dict); ok && len(g.items) > 1 {
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panic("Error in Values: if Dict is used, must be one item only")
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}
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}
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if !first && g.separator != "" {
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// The separator token is added before each non-null item, but not before the first item.
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if _, err := w.Write([]byte(g.separator)); err != nil {
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return false, err
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}
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}
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if g.multi {
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// For multi-line blocks, we insert a new line before each non-null item.
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if _, err := w.Write([]byte("\n")); err != nil {
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return false, err
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}
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}
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if err := code.render(f, w, nil); err != nil {
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return false, err
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}
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first = false
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}
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return first, nil
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}
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// Render renders the Group to the provided writer.
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func (g *Group) Render(writer io.Writer) error {
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return g.RenderWithFile(writer, NewFile(""))
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}
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// GoString renders the Group for testing. Any error will cause a panic.
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func (g *Group) GoString() string {
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buf := bytes.Buffer{}
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if err := g.Render(&buf); err != nil {
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panic(err)
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}
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return buf.String()
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}
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// RenderWithFile renders the Group to the provided writer, using imports from the provided file.
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func (g *Group) RenderWithFile(writer io.Writer, file *File) error {
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buf := &bytes.Buffer{}
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if err := g.render(file, buf, nil); err != nil {
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return err
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}
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b, err := format.Source(buf.Bytes())
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if err != nil {
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return fmt.Errorf("Error %s while formatting source:\n%s", err, buf.String())
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}
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if _, err := writer.Write(b); err != nil {
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return err
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}
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return nil
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}
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