first re-attempt at custom typewriter imports

lots of stuff, including use of cli package; gen get; gen custom

Author: clipperhouse

custom.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func custom() {
+	w, err := os.Create("_gen.go")
+
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	defer w.Close()
+
+	p := pkg{
+		Name:    "main",
+		Imports: stdImports,
+		Main:    false,
+	}
+
+	write(w, p)
+}

get.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"go/parser"
+	"go/token"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+func get(u bool) {
+	imports := make([]string, 0)
+
+	if _, err := os.Open("_gen.go"); err == nil {
+		// custom file exists, parse its imports
+		fset := token.NewFileSet()
+		if f, err := parser.ParseFile(fset, "_gen.go", nil, parser.ImportsOnly); err == nil {
+			for _, v := range f.Imports {
+				imports = append(imports, v.Path.Value)
+			}
+		}
+	} else {
+		// doesn't exist, use standard
+		imports = append(imports, stdImports...)
+	}
+
+	// clean `em up, hacky; TODO: a better way
+	for i := range imports {
+		imports[i] = strings.Trim(imports[i], `_ "`)
+	}
+
+	get := []string{"get"}
+	if u {
+		get = append(get, "-u")
+	}
+
+	get = append(get, imports...)
+
+	var out bytes.Buffer
+
+	cmd := exec.Command("go", get...)
+	cmd.Stdout = &out
+	cmd.Stderr = &out
+
+	if err := cmd.Run(); err != nil {
+		fmt.Println(err)
+	}
+
+	if out.Len() > 0 {
+		fmt.Println(out.String())
+	}
+}

imports.go

@@ -0,0 +1,6 @@
+package main
+
+import (
+	_ "github.com/clipperhouse/gen/typewriters/container"
+	_ "github.com/clipperhouse/gen/typewriters/genwriter"
+)

main.go

@@ -0,0 +1,12 @@
+package main
+
+var stdImports = []string{
+	`_ "github.com/clipperhouse/gen/typewriters/container"`,
+	`_ "github.com/clipperhouse/gen/typewriters/genwriter"`,
+}
+
+type pkg struct {
+	Name    string
+	Imports []string
+	Main    bool
+}

pkg.go

@@ -0,0 +1,93 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/clipperhouse/gen/typewriter"
+)
+
+func run() {
+	if src, err := os.Open("_gen.go"); err == nil {
+		// custom imports file exists, use it
+		runCustom(src)
+	} else {
+		// do it the regular way
+		runStandard()
+	}
+}
+
+func runStandard() {
+	app, err := typewriter.NewApp("+gen")
+
+	if err != nil {
+		panic(err)
+	}
+
+	if err := app.WriteAll(); err != nil {
+		panic(err)
+	}
+}
+
+func runCustom(src *os.File) {
+	defer src.Close()
+
+	temp, err := getTempDir()
+	if err != nil {
+		// TODO return err?
+		fmt.Println(err)
+		return
+	}
+	defer os.RemoveAll(temp)
+
+	// set up imports file containing the custom typewriters (from _gen.go)
+	imports, err := os.Create(filepath.Join(temp, "imports.go"))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer imports.Close()
+
+	io.Copy(imports, src)
+
+	// set up main to be run
+	main, err := os.Create(filepath.Join(temp, "main.go"))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer main.Close()
+
+	p := pkg{
+		Name: "main",
+		Imports: []string{
+			`"github.com/clipperhouse/gen/typewriter"`,
+		},
+		Main: true,
+	}
+	tmpl.Execute(main, p)
+
+	var out bytes.Buffer
+
+	cmd := exec.Command("go", "run", main.Name(), imports.Name())
+	cmd.Dir = temp
+	cmd.Stdout = &out
+	cmd.Stderr = &out
+
+	if err = cmd.Run(); err != nil {
+		fmt.Println(err)
+	}
+
+	if out.Len() > 0 {
+		fmt.Println(out.String())
+	}
+
+	if strings.Contains(out.String(), "cannot find package") {
+		fmt.Println("try running `go get` for individual imports in _gen.go")
+	}
+}

run.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"text/template"
+)
+
+// set up temp directory under current directory
+// make sure to defer os.RemoveAll() in caller
+func getTempDir() (string, error) {
+	caller := filepath.Base(os.Args[0])
+	wd, _ := os.Getwd()
+	return ioutil.TempDir(wd, caller)
+}
+
+func write(w io.Writer, p pkg) {
+	tmpl.Execute(w, p)
+}
+
+var tmpl = template.Must(template.New("package").Parse(`package {{.Name}}
+{{if gt (len .Imports) 0}}
+import ({{range .Imports}}
+	{{.}}{{end}}
+)
+{{end}}
+{{if .Main}}
+func main() {
+	app, err := typewriter.NewApp("+gen")
+
+	if err != nil {
+		panic(err)
+	}
+
+	if err := app.WriteAll(); err != nil {
+		panic(err)
+	}
+}
+{{end}}
+`))