feat(updater): initial

Author: christophwitzko

test-fixtures/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "test-package",
+  "version": "1.0.0"
+}

update/package_json.go

@@ -0,0 +1,26 @@
+package update
+
+import (
+	"encoding/json"
+	"os"
+)
+
+func init() {
+	Register("package.json", packageJson)
+}
+
+func packageJson(newVersion string, file *os.File) error {
+	var data map[string]json.RawMessage
+	if err := json.NewDecoder(file).Decode(&data); err != nil {
+		return err
+	}
+	data["version"] = json.RawMessage("\"" + newVersion + "\"")
+	file.Seek(0, 0)
+	file.Truncate(0)
+	enc := json.NewEncoder(file)
+	enc.SetIndent("", "  ")
+	if err := enc.Encode(data); err != nil {
+		return err
+	}
+	return nil
+}

update/package_json_test.go

@@ -0,0 +1,24 @@
+package update
+
+import (
+	"bytes"
+	"encoding/json"
+	"os"
+	"testing"
+)
+
+func TestPackageJson(t *testing.T) {
+	f, err := os.OpenFile("../test-fixtures/package.json", os.O_RDWR, 0)
+	if err != nil {
+		t.Fatal("fixture missing")
+	}
+	defer f.Close()
+	nVer := "1.2.3"
+	packageJson(nVer, f)
+	f.Seek(0, 0)
+	var data map[string]json.RawMessage
+	json.NewDecoder(f).Decode(&data)
+	if bytes.Compare(data["version"], []byte("\""+nVer+"\"")) != 0 {
+		t.Fatal("invalid version")
+	}
+}

update/update.go

@@ -0,0 +1,35 @@
+package update
+
+import (
+	"errors"
+	"os"
+	"path"
+	"sync"
+)
+
+type Updater func(string, *os.File) error
+
+var updatersMu sync.RWMutex
+var updaters = make(map[string]Updater)
+
+var ErrNoUpdater = errors.New("no updater registered")
+
+func Register(name string, u Updater) {
+	updatersMu.Lock()
+	defer updatersMu.Unlock()
+	updaters[name] = u
+}
+
+func Apply(file, newVersion string) error {
+	name := path.Base(file)
+	ufn, ok := updaters[name]
+	if !ok {
+		return ErrNoUpdater
+	}
+	f, err := os.OpenFile(file, os.O_RDWR, 0)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	return ufn(newVersion, f)
+}

update/update_test.go

@@ -0,0 +1,29 @@
+package update
+
+import (
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestRegisterApply(t *testing.T) {
+	nVer := "1.2.3"
+	Register("package.json", func(newVersion string, file *os.File) error {
+		if newVersion != nVer {
+			t.Fatal("invalid version")
+		}
+		return nil
+	})
+	if err := Apply("../test-fixtures/package.json", nVer); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestApply(t *testing.T) {
+	if err := Apply("invalidFile", ""); err != ErrNoUpdater {
+		t.Fatal(err)
+	}
+	if err := Apply("not/existing/package.json", ""); !strings.Contains(err.Error(), "no such file or directory") {
+		t.Fatal(err)
+	}
+}