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Diffstat (limited to 'src/pkg/go/ast/commentmap.go')
| -rw-r--r-- | src/pkg/go/ast/commentmap.go | 332 |
1 files changed, 0 insertions, 332 deletions
diff --git a/src/pkg/go/ast/commentmap.go b/src/pkg/go/ast/commentmap.go deleted file mode 100644 index ac999d627..000000000 --- a/src/pkg/go/ast/commentmap.go +++ /dev/null @@ -1,332 +0,0 @@ -// Copyright 2012 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -package ast - -import ( - "bytes" - "fmt" - "go/token" - "sort" -) - -type byPos []*CommentGroup - -func (a byPos) Len() int { return len(a) } -func (a byPos) Less(i, j int) bool { return a[i].Pos() < a[j].Pos() } -func (a byPos) Swap(i, j int) { a[i], a[j] = a[j], a[i] } - -// sortComments sorts the list of comment groups in source order. -// -func sortComments(list []*CommentGroup) { - // TODO(gri): Does it make sense to check for sorted-ness - // first (because we know that sorted-ness is - // very likely)? - if orderedList := byPos(list); !sort.IsSorted(orderedList) { - sort.Sort(orderedList) - } -} - -// A CommentMap maps an AST node to a list of comment groups -// associated with it. See NewCommentMap for a description of -// the association. -// -type CommentMap map[Node][]*CommentGroup - -func (cmap CommentMap) addComment(n Node, c *CommentGroup) { - list := cmap[n] - if len(list) == 0 { - list = []*CommentGroup{c} - } else { - list = append(list, c) - } - cmap[n] = list -} - -type byInterval []Node - -func (a byInterval) Len() int { return len(a) } -func (a byInterval) Less(i, j int) bool { - pi, pj := a[i].Pos(), a[j].Pos() - return pi < pj || pi == pj && a[i].End() > a[j].End() -} -func (a byInterval) Swap(i, j int) { a[i], a[j] = a[j], a[i] } - -// nodeList returns the list of nodes of the AST n in source order. -// -func nodeList(n Node) []Node { - var list []Node - Inspect(n, func(n Node) bool { - // don't collect comments - switch n.(type) { - case nil, *CommentGroup, *Comment: - return false - } - list = append(list, n) - return true - }) - // Note: The current implementation assumes that Inspect traverses the - // AST in depth-first and thus _source_ order. If AST traversal - // does not follow source order, the sorting call below will be - // required. - // sort.Sort(byInterval(list)) - return list -} - -// A commentListReader helps iterating through a list of comment groups. -// -type commentListReader struct { - fset *token.FileSet - list []*CommentGroup - index int - comment *CommentGroup // comment group at current index - pos, end token.Position // source interval of comment group at current index -} - -func (r *commentListReader) eol() bool { - return r.index >= len(r.list) -} - -func (r *commentListReader) next() { - if !r.eol() { - r.comment = r.list[r.index] - r.pos = r.fset.Position(r.comment.Pos()) - r.end = r.fset.Position(r.comment.End()) - r.index++ - } -} - -// A nodeStack keeps track of nested nodes. -// A node lower on the stack lexically contains the nodes higher on the stack. -// -type nodeStack []Node - -// push pops all nodes that appear lexically before n -// and then pushes n on the stack. -// -func (s *nodeStack) push(n Node) { - s.pop(n.Pos()) - *s = append((*s), n) -} - -// pop pops all nodes that appear lexically before pos -// (i.e., whose lexical extent has ended before or at pos). -// It returns the last node popped. -// -func (s *nodeStack) pop(pos token.Pos) (top Node) { - i := len(*s) - for i > 0 && (*s)[i-1].End() <= pos { - top = (*s)[i-1] - i-- - } - *s = (*s)[0:i] - return top -} - -// 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 incoming 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 -} - -// Update replaces an old node in the comment map with the new node -// and returns the new node. Comments that were associated with the -// old node are associated with the new node. -// -func (cmap CommentMap) Update(old, new Node) Node { - if list := cmap[old]; len(list) > 0 { - delete(cmap, old) - cmap[new] = append(cmap[new], list...) - } - return new -} - -// Filter returns a new comment map consisting of only those -// entries of cmap for which a corresponding node exists in -// the AST specified by node. -// -func (cmap CommentMap) Filter(node Node) CommentMap { - umap := make(CommentMap) - Inspect(node, func(n Node) bool { - if g := cmap[n]; len(g) > 0 { - umap[n] = g - } - return true - }) - return umap -} - -// Comments returns the list of comment groups in the comment map. -// The result is sorted is source order. -// -func (cmap CommentMap) Comments() []*CommentGroup { - list := make([]*CommentGroup, 0, len(cmap)) - for _, e := range cmap { - list = append(list, e...) - } - sortComments(list) - return list -} - -func summary(list []*CommentGroup) string { - const maxLen = 40 - var buf bytes.Buffer - - // collect comments text -loop: - for _, group := range list { - // Note: CommentGroup.Text() does too much work for what we - // need and would only replace this innermost loop. - // Just do it explicitly. - for _, comment := range group.List { - if buf.Len() >= maxLen { - break loop - } - buf.WriteString(comment.Text) - } - } - - // truncate if too long - if buf.Len() > maxLen { - buf.Truncate(maxLen - 3) - buf.WriteString("...") - } - - // replace any invisibles with blanks - bytes := buf.Bytes() - for i, b := range bytes { - switch b { - case '\t', '\n', '\r': - bytes[i] = ' ' - } - } - - return string(bytes) -} - -func (cmap CommentMap) String() string { - var buf bytes.Buffer - fmt.Fprintln(&buf, "CommentMap {") - for node, comment := range cmap { - // print name of identifiers; print node type for other nodes - var s string - if ident, ok := node.(*Ident); ok { - s = ident.Name - } else { - s = fmt.Sprintf("%T", node) - } - fmt.Fprintf(&buf, "\t%p %20s: %s\n", node, s, summary(comment)) - } - fmt.Fprintln(&buf, "}") - return buf.String() -} |