cmd/allsrc: WIP tool to print out all a program's source

Change-Id: Ie8ed3ad744af5b5b7772cb9b4516a9b8e2f2866d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

cmd/allsrc/allsrc.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"sort"
+
+	"golang.org/x/tools/go/packages"
+)
+
+var cfg = &packages.Config{
+	Mode: (0 |
+		packages.NeedName |
+		packages.NeedFiles |
+		packages.NeedCompiledGoFiles |
+		packages.NeedImports |
+		packages.NeedDeps |
+		packages.NeedModule |
+		packages.NeedTypes |
+		packages.NeedSyntax |
+		0),
+}
+
+func main() {
+	flag.Parse()
+
+	var w walker
+	w.walk("tailscale.com/cmd/tailscaled")
+}
+
+type walker struct {
+	done map[string]bool
+}
+
+func (w *walker) walk(mainPkg string) {
+	pkgs, err := packages.Load(cfg, mainPkg)
+	if err != nil {
+		log.Fatalf("packages.Load: %v", err)
+	}
+	for _, pkg := range pkgs {
+		w.walkPackage(pkg)
+	}
+}
+
+func (w *walker) walkPackage(pkg *packages.Package) {
+	if w.done[pkg.PkgPath] {
+		return
+	}
+	if w.done == nil {
+		w.done = map[string]bool{}
+	}
+	w.done[pkg.PkgPath] = true
+
+	fmt.Printf("\n### PACKAGE %v\n", pkg.PkgPath)
+
+	if len(pkg.Errors) > 0 {
+		log.Fatalf("errors reading %q: %q", pkg.PkgPath, pkg.Errors)
+	}
+
+	var imports []*packages.Package
+	for _, p := range pkg.Imports {
+		imports = append(imports, p)
+	}
+	sort.Slice(imports, func(i, j int) bool {
+		return imports[i].PkgPath < imports[j].PkgPath
+	})
+	for _, f := range pkg.GoFiles {
+		fmt.Printf("file.go %q\n", f)
+	}
+	for _, f := range pkg.OtherFiles {
+		fmt.Printf("file.other %q\n", f)
+	}
+	for _, p := range imports {
+		fmt.Printf("import %q => %q\n", pkg.PkgPath, p.PkgPath)
+	}
+	fmt.Printf("Fset: %p\n", pkg.Fset)
+	fmt.Printf("Syntax: %v\n", len(pkg.Syntax))
+	fmt.Printf("Modules: %+v\n", pkg.Module)
+
+	for _, p := range imports {
+		w.walkPackage(p)
+	}
+}