114 lines
2.2 KiB
Go
114 lines
2.2 KiB
Go
package rule
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import (
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"go/ast"
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"go/token"
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"github.com/mgechev/revive/lint"
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)
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// EmptyLinesRule lints empty lines in blocks.
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type EmptyLinesRule struct{}
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// Apply applies the rule to given file.
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func (r *EmptyLinesRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure {
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var failures []lint.Failure
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onFailure := func(failure lint.Failure) {
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failures = append(failures, failure)
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}
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w := lintEmptyLines{file, file.CommentMap(), onFailure}
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ast.Walk(w, file.AST)
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return failures
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}
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// Name returns the rule name.
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func (r *EmptyLinesRule) Name() string {
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return "empty-lines"
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}
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type lintEmptyLines struct {
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file *lint.File
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cmap ast.CommentMap
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onFailure func(lint.Failure)
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}
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func (w lintEmptyLines) Visit(node ast.Node) ast.Visitor {
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block, ok := node.(*ast.BlockStmt)
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if !ok {
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return w
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}
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w.checkStart(block)
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w.checkEnd(block)
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return w
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}
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func (w lintEmptyLines) checkStart(block *ast.BlockStmt) {
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if len(block.List) == 0 {
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return
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}
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start := w.position(block.Lbrace)
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firstNode := block.List[0]
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if w.commentBetween(start, firstNode) {
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return
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}
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first := w.position(firstNode.Pos())
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if first.Line-start.Line > 1 {
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w.onFailure(lint.Failure{
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Confidence: 1,
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Node: block,
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Category: "style",
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Failure: "extra empty line at the start of a block",
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})
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}
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}
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func (w lintEmptyLines) checkEnd(block *ast.BlockStmt) {
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if len(block.List) < 1 {
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return
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}
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end := w.position(block.Rbrace)
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lastNode := block.List[len(block.List)-1]
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if w.commentBetween(end, lastNode) {
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return
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}
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last := w.position(lastNode.End())
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if end.Line-last.Line > 1 {
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w.onFailure(lint.Failure{
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Confidence: 1,
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Node: lastNode,
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Category: "style",
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Failure: "extra empty line at the end of a block",
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})
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}
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}
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func (w lintEmptyLines) commentBetween(position token.Position, node ast.Node) bool {
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comments := w.cmap.Filter(node).Comments()
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if len(comments) == 0 {
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return false
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}
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for _, comment := range comments {
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start, end := w.position(comment.Pos()), w.position(comment.End())
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if start.Line-position.Line == 1 || position.Line-end.Line == 1 {
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return true
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}
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}
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return false
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}
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func (w lintEmptyLines) position(pos token.Pos) token.Position {
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return w.file.ToPosition(pos)
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}
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