From 4b3f1037b3b21960b7bae3910c0fbb320da043fd Mon Sep 17 00:00:00 2001
From: Kyle <kyle@tyrfingr.is>
Date: Tue, 22 Sep 2015 11:25:54 -0700
Subject: [PATCH] Add showimp to commands.

---
 cmd/showimp/README.md |  21 ++++++++
 cmd/showimp/main.go   | 110 ++++++++++++++++++++++++++++++++++++++++++
 lib/lib.go            |   9 ++++
 3 files changed, 140 insertions(+)
 create mode 100644 cmd/showimp/README.md
 create mode 100644 cmd/showimp/main.go

diff --git a/cmd/showimp/README.md b/cmd/showimp/README.md
new file mode 100644
index 0000000..cd45897
--- /dev/null
+++ b/cmd/showimp/README.md
@@ -0,0 +1,21 @@
+# showimp
+## show imports
+
+This will run over a source tree and print any imports that are not in
+the standard library or inside the project.
+
+```
+kyle@nocturne:~/src/github.com/kisom/cryptutils$ showimp 
+External imports:
+        code.google.com/p/go.crypto/bcrypt
+        code.google.com/p/go.crypto/nacl/box
+        code.google.com/p/go.crypto/nacl/secretbox
+        code.google.com/p/go.crypto/scrypt
+        code.google.com/p/rsc/qr
+        github.com/agl/ed25519
+        github.com/conformal/yubikey
+        github.com/gokyle/readpass
+        github.com/gokyle/twofactor
+        github.com/gorilla/mux
+```
+
diff --git a/cmd/showimp/main.go b/cmd/showimp/main.go
new file mode 100644
index 0000000..d47c770
--- /dev/null
+++ b/cmd/showimp/main.go
@@ -0,0 +1,110 @@
+// showimp is a utility for displaying the imports in a package.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"go/parser"
+	"go/token"
+	"os"
+	"path/filepath"
+	"regexp"
+	"sort"
+	"strings"
+
+	"github.com/kisom/goutils/die"
+	"github.com/kisom/goutils/logging"
+)
+
+var (
+	gopath  string
+	project string
+)
+
+var (
+	stdLibRegexp = regexp.MustCompile(`^\w+(/\w+)*$`)
+	sourceRegexp = regexp.MustCompile(`^[^.].*\.go$`)
+	log          = logging.Init()
+)
+
+func init() {
+	gopath = os.Getenv("GOPATH")
+	if gopath == "" {
+		fmt.Fprintf(os.Stderr, "GOPATH isn't set, can't proceed.")
+		os.Exit(1)
+	}
+	gopath += "/src/"
+
+	wd, err := os.Getwd()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Unable to establish working directory: %v", err)
+		os.Exit(1)
+	}
+
+	if !strings.HasPrefix(wd, gopath) {
+		fmt.Fprintf(os.Stderr, "Can't determine my location in the GOPATH.\n")
+		fmt.Fprintf(os.Stderr, "Working directory is %s\n", wd)
+		fmt.Fprintf(os.Stderr, "Go source path is %s\n", gopath)
+		os.Exit(1)
+	}
+
+	project = wd[len(gopath):]
+}
+
+var (
+	imports = map[string]bool{}
+	fset    = &token.FileSet{}
+)
+
+func walkFile(path string, info os.FileInfo, err error) error {
+	if !sourceRegexp.MatchString(path) {
+		return nil
+	}
+
+	log.Debug(path)
+
+	f, err := parser.ParseFile(fset, path, nil, parser.ImportsOnly)
+	if err != nil {
+		return err
+	}
+
+	for _, importSpec := range f.Imports {
+		importPath := strings.Trim(importSpec.Path.Value, `"`)
+		if stdLibRegexp.MatchString(importPath) {
+			log.Debug("standard lib:", importPath)
+			continue
+		} else if strings.HasPrefix(importPath, project) {
+			log.Debug("internal import:", importPath)
+			continue
+		} else if strings.HasPrefix(importPath, "golang.org/") {
+			log.Debug("extended lib:", importPath)
+			continue
+		}
+		log.Debug("import:", importPath)
+		imports[importPath] = true
+	}
+
+	return nil
+}
+
+func main() {
+	verbose := flag.Bool("v", false, "log debugging information")
+	flag.Parse()
+
+	if *verbose {
+		log.SetLevel(logging.LevelDebug)
+	}
+	err := filepath.Walk(".", walkFile)
+	die.If(err)
+
+	fmt.Println("External imports:")
+	importList := make([]string, 0, len(imports))
+	for imp := range imports {
+		importList = append(importList, imp)
+	}
+	sort.Strings(importList)
+
+	for _, imp := range importList {
+		fmt.Println("\t", imp)
+	}
+}
diff --git a/lib/lib.go b/lib/lib.go
index 42178fc..9d207ed 100644
--- a/lib/lib.go
+++ b/lib/lib.go
@@ -45,3 +45,12 @@ func Err(exit int, err error, format string, a ...interface{}) {
 	fmt.Fprintf(os.Stderr, format, a...)
 	os.Exit(exit)
 }
+
+// CheckFatal calls Err if err isn't nil.
+func CheckFatal(err error, format string, a ...interface{}) {
+	if err == nil {
+		return
+	}
+
+	Err(ExitFailure, err, format, a...)
+}