--- /dev/null
+package source
+
+import (
+ "context"
+ "go/ast"
+ "go/token"
+ "sort"
+
+ "golang.org/x/tools/internal/lsp/protocol"
+)
+
+// FoldingRangeInfo holds range and kind info of folding for an ast.Node
+type FoldingRangeInfo struct {
+ MappedRange
+ Kind protocol.FoldingRangeKind
+}
+
+// FoldingRange gets all of the folding range for f.
+func FoldingRange(ctx context.Context, snapshot Snapshot, fh FileHandle, lineFoldingOnly bool) (ranges []*FoldingRangeInfo, err error) {
+ // TODO(suzmue): consider limiting the number of folding ranges returned, and
+ // implement a way to prioritize folding ranges in that case.
+ pgf, err := snapshot.ParseGo(ctx, fh, ParseFull)
+ if err != nil {
+ return nil, err
+ }
+ fset := snapshot.FileSet()
+
+ // Get folding ranges for comments separately as they are not walked by ast.Inspect.
+ ranges = append(ranges, commentsFoldingRange(fset, pgf.Mapper, pgf.File)...)
+
+ visit := func(n ast.Node) bool {
+ rng := foldingRangeFunc(fset, pgf.Mapper, n, lineFoldingOnly)
+ if rng != nil {
+ ranges = append(ranges, rng)
+ }
+ return true
+ }
+ // Walk the ast and collect folding ranges.
+ ast.Inspect(pgf.File, visit)
+
+ sort.Slice(ranges, func(i, j int) bool {
+ irng, _ := ranges[i].Range()
+ jrng, _ := ranges[j].Range()
+ return protocol.CompareRange(irng, jrng) < 0
+ })
+
+ return ranges, nil
+}
+
+// foldingRangeFunc calculates the line folding range for ast.Node n
+func foldingRangeFunc(fset *token.FileSet, m *protocol.ColumnMapper, n ast.Node, lineFoldingOnly bool) *FoldingRangeInfo {
+ // TODO(suzmue): include trailing empty lines before the closing
+ // parenthesis/brace.
+ var kind protocol.FoldingRangeKind
+ var start, end token.Pos
+ switch n := n.(type) {
+ case *ast.BlockStmt:
+ // Fold between positions of or lines between "{" and "}".
+ var startList, endList token.Pos
+ if num := len(n.List); num != 0 {
+ startList, endList = n.List[0].Pos(), n.List[num-1].End()
+ }
+ start, end = validLineFoldingRange(fset, n.Lbrace, n.Rbrace, startList, endList, lineFoldingOnly)
+ case *ast.CaseClause:
+ // Fold from position of ":" to end.
+ start, end = n.Colon+1, n.End()
+ case *ast.CommClause:
+ // Fold from position of ":" to end.
+ start, end = n.Colon+1, n.End()
+ case *ast.CallExpr:
+ // Fold from position of "(" to position of ")".
+ start, end = n.Lparen+1, n.Rparen
+ case *ast.FieldList:
+ // Fold between positions of or lines between opening parenthesis/brace and closing parenthesis/brace.
+ var startList, endList token.Pos
+ if num := len(n.List); num != 0 {
+ startList, endList = n.List[0].Pos(), n.List[num-1].End()
+ }
+ start, end = validLineFoldingRange(fset, n.Opening, n.Closing, startList, endList, lineFoldingOnly)
+ case *ast.GenDecl:
+ // If this is an import declaration, set the kind to be protocol.Imports.
+ if n.Tok == token.IMPORT {
+ kind = protocol.Imports
+ }
+ // Fold between positions of or lines between "(" and ")".
+ var startSpecs, endSpecs token.Pos
+ if num := len(n.Specs); num != 0 {
+ startSpecs, endSpecs = n.Specs[0].Pos(), n.Specs[num-1].End()
+ }
+ start, end = validLineFoldingRange(fset, n.Lparen, n.Rparen, startSpecs, endSpecs, lineFoldingOnly)
+ case *ast.CompositeLit:
+ // Fold between positions of or lines between "{" and "}".
+ var startElts, endElts token.Pos
+ if num := len(n.Elts); num != 0 {
+ startElts, endElts = n.Elts[0].Pos(), n.Elts[num-1].End()
+ }
+ start, end = validLineFoldingRange(fset, n.Lbrace, n.Rbrace, startElts, endElts, lineFoldingOnly)
+ }
+
+ // Check that folding positions are valid.
+ if !start.IsValid() || !end.IsValid() {
+ return nil
+ }
+ // in line folding mode, do not fold if the start and end lines are the same.
+ if lineFoldingOnly && fset.Position(start).Line == fset.Position(end).Line {
+ return nil
+ }
+ return &FoldingRangeInfo{
+ MappedRange: NewMappedRange(fset, m, start, end),
+ Kind: kind,
+ }
+}
+
+// validLineFoldingRange returns start and end token.Pos for folding range if the range is valid.
+// returns token.NoPos otherwise, which fails token.IsValid check
+func validLineFoldingRange(fset *token.FileSet, open, close, start, end token.Pos, lineFoldingOnly bool) (token.Pos, token.Pos) {
+ if lineFoldingOnly {
+ if !open.IsValid() || !close.IsValid() {
+ return token.NoPos, token.NoPos
+ }
+
+ // Don't want to fold if the start/end is on the same line as the open/close
+ // as an example, the example below should *not* fold:
+ // var x = [2]string{"d",
+ // "e" }
+ if fset.Position(open).Line == fset.Position(start).Line ||
+ fset.Position(close).Line == fset.Position(end).Line {
+ return token.NoPos, token.NoPos
+ }
+
+ return open + 1, end
+ }
+ return open + 1, close
+}
+
+// commentsFoldingRange returns the folding ranges for all comment blocks in file.
+// The folding range starts at the end of the first comment, and ends at the end of the
+// comment block and has kind protocol.Comment.
+func commentsFoldingRange(fset *token.FileSet, m *protocol.ColumnMapper, file *ast.File) (comments []*FoldingRangeInfo) {
+ for _, commentGrp := range file.Comments {
+ // Don't fold single comments.
+ if len(commentGrp.List) <= 1 {
+ continue
+ }
+ comments = append(comments, &FoldingRangeInfo{
+ // Fold from the end of the first line comment to the end of the comment block.
+ MappedRange: NewMappedRange(fset, m, commentGrp.List[0].End(), commentGrp.End()),
+ Kind: protocol.Comment,
+ })
+ }
+ return comments
+}
projects / dotfiles / .git / blobdiff