Example #1
0
func newSnippet(fset *token.FileSet, decl ast.Decl, id *ast.Ident) *Snippet {
	// TODO instead of pretty-printing the node, should use the original source instead
	var buf1 bytes.Buffer
	writeNode(&buf1, fset, decl)
	// wrap text with <pre> tag
	var buf2 bytes.Buffer
	buf2.WriteString("<pre>")
	FormatText(&buf2, buf1.Bytes(), -1, true, id.Name, nil)
	buf2.WriteString("</pre>")
	return &Snippet{fset.Position(id.Pos()).Line, buf2.String()}
}
Example #2
0
// NewSnippet creates a text snippet from a declaration decl containing an
// identifier id. Parts of the declaration not containing the identifier
// may be removed for a more compact snippet.
//
func NewSnippet(fset *token.FileSet, decl ast.Decl, id *ast.Ident) (s *Snippet) {
	switch d := decl.(type) {
	case *ast.GenDecl:
		s = genSnippet(fset, d, id)
	case *ast.FuncDecl:
		s = funcSnippet(fset, d, id)
	}

	// handle failure gracefully
	if s == nil {
		var buf bytes.Buffer
		fmt.Fprintf(&buf, `<span class="alert">could not generate a snippet for <span class="highlight">%s</span></span>`, id.Name)
		s = &Snippet{fset.Position(id.Pos()).Line, buf.String()}
	}
	return
}
Example #3
0
// SortImports sorts runs of consecutive import lines in import blocks in f.
// It also removes duplicate imports when it is possible to do so without data loss.
func SortImports(fset *token.FileSet, f *File) {
	for _, d := range f.Decls {
		d, ok := d.(*GenDecl)
		if !ok || d.Tok != token.IMPORT {
			// Not an import declaration, so we're done.
			// Imports are always first.
			break
		}

		if !d.Lparen.IsValid() {
			// Not a block: sorted by default.
			continue
		}

		// Identify and sort runs of specs on successive lines.
		i := 0
		specs := d.Specs[:0]
		for j, s := range d.Specs {
			if j > i && fset.Position(s.Pos()).Line > 1+fset.Position(d.Specs[j-1].End()).Line {
				// j begins a new run.  End this one.
				specs = append(specs, sortSpecs(fset, f, d.Specs[i:j])...)
				i = j
			}
		}
		specs = append(specs, sortSpecs(fset, f, d.Specs[i:])...)
		d.Specs = specs

		// Deduping can leave a blank line before the rparen; clean that up.
		if len(d.Specs) > 0 {
			lastSpec := d.Specs[len(d.Specs)-1]
			lastLine := fset.Position(lastSpec.Pos()).Line
			if rParenLine := fset.Position(d.Rparen).Line; rParenLine > lastLine+1 {
				fset.File(d.Rparen).MergeLine(rParenLine - 1)
			}
		}
	}
}
Example #4
0
func sortSpecs(fset *token.FileSet, f *File, specs []Spec) []Spec {
	// Can't short-circuit here even if specs are already sorted,
	// since they might yet need deduplication.
	// A lone import, however, may be safely ignored.
	if len(specs) <= 1 {
		return specs
	}

	// Record positions for specs.
	pos := make([]posSpan, len(specs))
	for i, s := range specs {
		pos[i] = posSpan{s.Pos(), s.End()}
	}

	// Identify comments in this range.
	// Any comment from pos[0].Start to the final line counts.
	lastLine := fset.Position(pos[len(pos)-1].End).Line
	cstart := len(f.Comments)
	cend := len(f.Comments)
	for i, g := range f.Comments {
		if g.Pos() < pos[0].Start {
			continue
		}
		if i < cstart {
			cstart = i
		}
		if fset.Position(g.End()).Line > lastLine {
			cend = i
			break
		}
	}
	comments := f.Comments[cstart:cend]

	// Assign each comment to the import spec preceding it.
	importComment := map[*ImportSpec][]*CommentGroup{}
	specIndex := 0
	for _, g := range comments {
		for specIndex+1 < len(specs) && pos[specIndex+1].Start <= g.Pos() {
			specIndex++
		}
		s := specs[specIndex].(*ImportSpec)
		importComment[s] = append(importComment[s], g)
	}

	// Sort the import specs by import path.
	// Remove duplicates, when possible without data loss.
	// Reassign the import paths to have the same position sequence.
	// Reassign each comment to abut the end of its spec.
	// Sort the comments by new position.
	sort.Sort(byImportSpec(specs))

	// Dedup. Thanks to our sorting, we can just consider
	// adjacent pairs of imports.
	deduped := specs[:0]
	for i, s := range specs {
		if i == len(specs)-1 || !collapse(s, specs[i+1]) {
			deduped = append(deduped, s)
		} else {
			p := s.Pos()
			fset.File(p).MergeLine(fset.Position(p).Line)
		}
	}
	specs = deduped

	// Fix up comment positions
	for i, s := range specs {
		s := s.(*ImportSpec)
		if s.Name != nil {
			s.Name.NamePos = pos[i].Start
		}
		s.Path.ValuePos = pos[i].Start
		s.EndPos = pos[i].End
		for _, g := range importComment[s] {
			for _, c := range g.List {
				c.Slash = pos[i].End
			}
		}
	}

	sort.Sort(byCommentPos(comments))

	return specs
}
Example #5
0
// NewCommentMap creates a new comment map by associating comment groups
// of the comments list with the nodes of the AST specified by node.
//
// A comment group g is associated with a node n if:
//
//   - g starts on the same line as n ends
//   - g starts on the line immediately following n, and there is
//     at least one empty line after g and before the next node
//   - g starts before n and is not associated to the node before n
//     via the previous rules
//
// NewCommentMap tries to associate a comment group to the "largest"
// node possible: For instance, if the comment is a line comment
// trailing an assignment, the comment is associated with the entire
// assignment rather than just the last operand in the assignment.
//
func NewCommentMap(fset *token.FileSet, node Node, comments []*CommentGroup) CommentMap {
	if len(comments) == 0 {
		return nil // no comments to map
	}

	cmap := make(CommentMap)

	// set up comment reader r
	tmp := make([]*CommentGroup, len(comments))
	copy(tmp, comments) // don't change incomming comments
	sortComments(tmp)
	r := commentListReader{fset: fset, list: tmp} // !r.eol() because len(comments) > 0
	r.next()

	// create node list in lexical order
	nodes := nodeList(node)
	nodes = append(nodes, nil) // append sentinel

	// set up iteration variables
	var (
		p     Node           // previous node
		pend  token.Position // end of p
		pg    Node           // previous node group (enclosing nodes of "importance")
		pgend token.Position // end of pg
		stack nodeStack      // stack of node groups
	)

	for _, q := range nodes {
		var qpos token.Position
		if q != nil {
			qpos = fset.Position(q.Pos()) // current node position
		} else {
			// set fake sentinel position to infinity so that
			// all comments get processed before the sentinel
			const infinity = 1 << 30
			qpos.Offset = infinity
			qpos.Line = infinity
		}

		// process comments before current node
		for r.end.Offset <= qpos.Offset {
			// determine recent node group
			if top := stack.pop(r.comment.Pos()); top != nil {
				pg = top
				pgend = fset.Position(pg.End())
			}
			// Try to associate a comment first with a node group
			// (i.e., a node of "importance" such as a declaration);
			// if that fails, try to associate it with the most recent
			// node.
			// TODO(gri) try to simplify the logic below
			var assoc Node
			switch {
			case pg != nil &&
				(pgend.Line == r.pos.Line ||
					pgend.Line+1 == r.pos.Line && r.end.Line+1 < qpos.Line):
				// 1) comment starts on same line as previous node group ends, or
				// 2) comment starts on the line immediately after the
				//    previous node group and there is an empty line before
				//    the current node
				// => associate comment with previous node group
				assoc = pg
			case p != nil &&
				(pend.Line == r.pos.Line ||
					pend.Line+1 == r.pos.Line && r.end.Line+1 < qpos.Line ||
					q == nil):
				// same rules apply as above for p rather than pg,
				// but also associate with p if we are at the end (q == nil)
				assoc = p
			default:
				// otherwise, associate comment with current node
				if q == nil {
					// we can only reach here if there was no p
					// which would imply that there were no nodes
					panic("internal error: no comments should be associated with sentinel")
				}
				assoc = q
			}
			cmap.addComment(assoc, r.comment)
			if r.eol() {
				return cmap
			}
			r.next()
		}

		// update previous node
		p = q
		pend = fset.Position(p.End())

		// update previous node group if we see an "important" node
		switch q.(type) {
		case *File, *Field, Decl, Spec, Stmt:
			stack.push(q)
		}
	}

	return cmap
}