1 files changed, 70 insertions, 22 deletions

diff --git a/vendor/golang.org/x/text/internal/gen/gen.go b/vendor/golang.org/x/text/internal/gen/gen.go
index dfaa278..9eb2987 100644
--- a/vendor/golang.org/x/text/internal/gen/gen.go
+++ b/vendor/golang.org/x/text/internal/gen/gen.go
@@ -22,6 +22,7 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
+	"go/build"
 	"go/format"
 	"io"
 	"io/ioutil"
@@ -30,6 +31,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"sync"
 	"unicode"
 
 	"golang.org/x/text/unicode/cldr"
@@ -48,12 +50,6 @@ var (
 	cldrVersion = flag.String("cldr",
 		getEnv("CLDR_VERSION", cldr.Version),
 		"cldr version to use")
-	// Allow an environment variable to specify the local directory.
-	// go generate doesn't allow specifying arguments; this is a useful
-	// alternative to specifying a local mirror.
-	localDir = flag.String("local",
-		os.Getenv("UNICODE_DIR"),
-		"directory containing local data files; for debugging only.")
 )
 
 func getEnv(name, def string) string {
@@ -87,9 +83,12 @@ func CLDRVersion() string {
 	return *cldrVersion
 }
 
-// IsLocal reports whether the user specified a local directory.
+// IsLocal reports whether data files are available locally.
 func IsLocal() bool {
-	return *localDir != ""
+	if _, err := os.Stat(localReadmeFile()); err != nil {
+		return false
+	}
+	return true
 }
 
 // OpenUCDFile opens the requested UCD file. The file is specified relative to
@@ -124,29 +123,78 @@ func OpenIANAFile(path string) io.ReadCloser {
 	return Open(*iana, "iana", path)
 }
 
+var (
+	dirMutex sync.Mutex
+	localDir string
+)
+
+const permissions = 0755
+
+func localReadmeFile() string {
+	p, err := build.Import("golang.org/x/text", "", build.FindOnly)
+	if err != nil {
+		log.Fatalf("Could not locate package: %v", err)
+	}
+	return filepath.Join(p.Dir, "DATA", "README")
+}
+
+func getLocalDir() string {
+	dirMutex.Lock()
+	defer dirMutex.Unlock()
+
+	readme := localReadmeFile()
+	dir := filepath.Dir(readme)
+	if _, err := os.Stat(readme); err != nil {
+		if err := os.MkdirAll(dir, permissions); err != nil {
+			log.Fatalf("Could not create directory: %v", err)
+		}
+		ioutil.WriteFile(readme, []byte(readmeTxt), permissions)
+	}
+	return dir
+}
+
+const readmeTxt = `Generated by golang.org/x/text/internal/gen. DO NOT EDIT.
+
+This directory contains downloaded files used to generate the various tables
+in the golang.org/x/text subrepo.
+
+Note that the language subtag repo (iana/assignments/language-subtag-registry)
+and all other times in the iana subdirectory are not versioned and will need
+to be periodically manually updated. The easiest way to do this is to remove
+the entire iana directory. This is mostly of concern when updating the language
+package.
+`
+
 // Open opens subdir/path if a local directory is specified and the file exists,
 // where subdir is a directory relative to the local root, or fetches it from
 // urlRoot/path otherwise. It will call log.Fatal if there are any errors.
 func Open(urlRoot, subdir, path string) io.ReadCloser {
-	if *localDir != "" {
-		path = filepath.FromSlash(path)
-		if f, err := os.Open(filepath.Join(*localDir, subdir, path)); err == nil {
-			return f
-		}
-	}
-	return get(urlRoot, path)
+	file := filepath.Join(getLocalDir(), subdir, filepath.FromSlash(path))
+	return open(file, urlRoot, path)
 }
 
 func openUnicode(path string) io.ReadCloser {
-	if *localDir != "" {
-		path = filepath.FromSlash(path)
-		f, err := os.Open(filepath.Join(*localDir, path))
-		if err != nil {
-			log.Fatal(err)
-		}
+	file := filepath.Join(getLocalDir(), filepath.FromSlash(path))
+	return open(file, *url, path)
+}
+
+// TODO: automatically periodically update non-versioned files.
+
+func open(file, urlRoot, path string) io.ReadCloser {
+	if f, err := os.Open(file); err == nil {
 		return f
 	}
-	return get(*url, path)
+	r := get(urlRoot, path)
+	defer r.Close()
+	b, err := ioutil.ReadAll(r)
+	if err != nil {
+		log.Fatalf("Could not download file: %v", err)
+	}
+	os.MkdirAll(filepath.Dir(file), permissions)
+	if err := ioutil.WriteFile(file, b, permissions); err != nil {
+		log.Fatalf("Could not create file: %v", err)
+	}
+	return ioutil.NopCloser(bytes.NewReader(b))
 }
 
 func get(root, path string) io.ReadCloser {