Add self-contained gometalinter build tooling.

tools/vendor/github.com/tsenart/deadcode/deadcode.go

@@ -0,0 +1,179 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"sort"
+	"strings"
+)
+
+var exitCode int
+
+func main() {
+	flag.Parse()
+	if flag.NArg() == 0 {
+		doDir(".")
+	} else {
+		for _, name := range flag.Args() {
+			// Is it a directory?
+			if fi, err := os.Stat(name); err == nil && fi.IsDir() {
+				doDir(name)
+			} else {
+				errorf("not a directory: %s", name)
+			}
+		}
+	}
+	os.Exit(exitCode)
+}
+
+// error formats the error to standard error, adding program
+// identification and a newline
+func errorf(format string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, "deadcode: "+format+"\n", args...)
+	exitCode = 2
+}
+
+func doDir(name string) {
+	notests := func(info os.FileInfo) bool {
+		if !info.IsDir() && strings.HasSuffix(info.Name(), ".go") &&
+			!strings.HasSuffix(info.Name(), "_test.go") {
+			return true
+		}
+		return false
+	}
+	fs := token.NewFileSet()
+	pkgs, err := parser.ParseDir(fs, name, notests, parser.Mode(0))
+	if err != nil {
+		errorf("%s", err)
+		return
+	}
+	for _, pkg := range pkgs {
+		doPackage(fs, pkg)
+	}
+}
+
+type Package struct {
+	p    *ast.Package
+	fs   *token.FileSet
+	decl map[string]ast.Node
+	used map[string]bool
+}
+
+func doPackage(fs *token.FileSet, pkg *ast.Package) {
+	p := &Package{
+		p:    pkg,
+		fs:   fs,
+		decl: make(map[string]ast.Node),
+		used: make(map[string]bool),
+	}
+	for _, file := range pkg.Files {
+		for _, decl := range file.Decls {
+			switch n := decl.(type) {
+			case *ast.GenDecl:
+				// var, const, types
+				for _, spec := range n.Specs {
+					switch s := spec.(type) {
+					case *ast.ValueSpec:
+						// constants and variables.
+						for _, name := range s.Names {
+							p.decl[name.Name] = n
+						}
+					case *ast.TypeSpec:
+						// type definitions.
+						p.decl[s.Name.Name] = n
+					}
+				}
+			case *ast.FuncDecl:
+				// function declarations
+				// TODO(remy): do methods
+				if n.Recv == nil {
+					p.decl[n.Name.Name] = n
+				}
+			}
+		}
+	}
+	// init() and _ are always used
+	p.used["init"] = true
+	p.used["_"] = true
+	if pkg.Name != "main" {
+		// exported names are marked used for non-main packages.
+		for name := range p.decl {
+			if ast.IsExported(name) {
+				p.used[name] = true
+			}
+		}
+	} else {
+		// in main programs, main() is called.
+		p.used["main"] = true
+	}
+	for _, file := range pkg.Files {
+		// walk file looking for used nodes.
+		ast.Walk(p, file)
+	}
+	// reports.
+	reports := Reports(nil)
+	for name, node := range p.decl {
+		if !p.used[name] {
+			reports = append(reports, Report{node.Pos(), name})
+		}
+	}
+	sort.Sort(reports)
+	for _, report := range reports {
+		errorf("%s: %s is unused", fs.Position(report.pos), report.name)
+	}
+}
+
+type Report struct {
+	pos  token.Pos
+	name string
+}
+type Reports []Report
+
+func (l Reports) Len() int           { return len(l) }
+func (l Reports) Less(i, j int) bool { return l[i].pos < l[j].pos }
+func (l Reports) Swap(i, j int)      { l[i], l[j] = l[j], l[i] }
+
+// Visits files for used nodes.
+func (p *Package) Visit(node ast.Node) ast.Visitor {
+	u := usedWalker(*p) // hopefully p fields are references.
+	switch n := node.(type) {
+	// don't walk whole file, but only:
+	case *ast.ValueSpec:
+		// - variable initializers
+		for _, value := range n.Values {
+			ast.Walk(&u, value)
+		}
+		// variable types.
+		if n.Type != nil {
+			ast.Walk(&u, n.Type)
+		}
+	case *ast.BlockStmt:
+		// - function bodies
+		for _, stmt := range n.List {
+			ast.Walk(&u, stmt)
+		}
+	case *ast.FuncDecl:
+		// - function signatures
+		ast.Walk(&u, n.Type)
+	case *ast.TypeSpec:
+		// - type declarations
+		ast.Walk(&u, n.Type)
+	}
+	return p
+}
+
+type usedWalker Package
+
+// Walks through the AST marking used identifiers.
+func (p *usedWalker) Visit(node ast.Node) ast.Visitor {
+	// just be stupid and mark all *ast.Ident
+	switch n := node.(type) {
+	case *ast.Ident:
+		p.used[n.Name] = true
+	}
+	return p
+}