add ci and readme badges (#1)

.github/workflows/go.yml

@@ -0,0 +1,22 @@
+# This file adheres to the YAML5 style.
+{
+  "name": "Go",
+  "on": ["push", "pull_request"],
+  "jobs": {
+    "build": {
+      "name": "Build",
+      "runs-on": "ubuntu-latest",
+      "steps": [
+        {
+          "name": "Set up Go 1.19",
+          "uses": "actions/setup-go@v1",
+          "with": {"go-version": 1.19},
+          "id": "go",
+        },
+        {"name": "Check out code into the Go module directory", "uses": "actions/checkout@v1"},
+        {"name": "Linter", "run": "make ci-lint"},
+        {"name": "Test", "run": "make test"},
+      ],
+    },
+  },
+}

Makefile

@@ -0,0 +1,15 @@
+GOPATH_DIR=`go env GOPATH`
+
+test:
+	go test -v -count=3 .
+
+ci-lint:
+	curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(GOPATH_DIR)/bin v1.54.2
+	$(GOPATH_DIR)/bin/golangci-lint run ./...
+	@echo "everything is OK"
+
+lint:
+	golangci-lint run ./...
+	@echo "everything is OK"
+
+.PHONY: ci-lint lint test

README.md

@@ -1,5 +1,8 @@
 # gdata
 
+![Build Status](https://github.com/quasilyte/gdata/workflows/Go/badge.svg)
+[![PkgGoDev](https://pkg.go.dev/badge/mod/github.com/quasilyte/gdata)](https://pkg.go.dev/mod/github.com/quasilyte/gdata)
+
 A gamedata package that provides a convenient cross-platform storage for games.
 
 Some examples of such gamedata that you might want to store:

gdata.go

@@ -14,6 +14,7 @@ type Manager struct {
 type dataManagerImpl interface {
 	SaveData(itemKey string, data []byte) error
 	LoadData(itemKey string) ([]byte, error)
+	DeleteData(itemKey string) error
 	DataExists(itemKey string) bool
 	DataPath(itemKey string) string
 }
@@ -74,6 +75,18 @@ func (m *Manager) LoadItem(itemKey string) ([]byte, error) {
 	return m.impl.LoadData(itemKey)
 }
 
+// DeleteItem removes the data associated with the itemKey.
+//
+// Be careful with this function: it removes the data permanently.
+// There is no way to undo it.
+//
+// Trying to delete a non-existing itemKey is not an error.
+//
+// The returned error is usually a file operation error.
+func (m *Manager) DeleteItem(itemKey string) error {
+	return m.impl.DeleteData(itemKey)
+}
+
 // ItemExists reports whether the itemKey was saved before.
 // An existing key will result in a non-nil data being read with LoadItem().
 func (m *Manager) ItemExists(itemKey string) bool {

gdata_android.go

@@ -39,6 +39,14 @@ func (m *dataManager) SaveData(itemKey string, data []byte) error {
 	return os.WriteFile(m.DataPath(itemKey), data, 0o666)
 }
 
+func (m *dataManager) DeleteData(itemKey string) error {
+	itemPath := m.DataPath(itemKey)
+	if !fileExists(itemPath) {
+		return nil
+	}
+	return os.Remove(itemPath)
+}
+
 func (m *dataManager) LoadData(itemKey string) ([]byte, error) {
 	itemPath := m.DataPath(itemKey)
 	if !fileExists(itemPath) {

gdata_js.go

@@ -44,6 +44,11 @@ func (m *dataManager) SaveData(itemKey string, data []byte) error {
 	return nil
 }
 
+func (m *dataManager) DeleteData(itemKey string) error {
+	js.Global().Get("localStorage").Call("removeItem", m.DataPath(itemKey))
+	return nil
+}
+
 func (m *dataManager) LoadData(itemKey string) ([]byte, error) {
 	result := js.Global().Get("localStorage").Call("getItem", m.DataPath(itemKey))
 	if result.IsNull() {

gdata_test.go

@@ -0,0 +1,56 @@
+package gdata_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/quasilyte/gdata"
+)
+
+func TestSaveLoad(t *testing.T) {
+	m, err := gdata.Open(gdata.Config{
+		AppName: "gdata_test",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	const testItemKey = "testitem.txt"
+
+	// Deleting a potentially non-existing item.
+	// For a second run it acts like a state reset function.
+	if err := m.DeleteItem(testItemKey); err != nil {
+		t.Fatalf("delete should never result in an error here (got %v)", err)
+	}
+
+	if m.ItemExists(testItemKey) {
+		t.Fatalf("%s item should not exist yet", testItemKey)
+	}
+
+	data := []byte("example data")
+	if err := m.SaveItem(testItemKey, data); err != nil {
+		t.Fatalf("error saving %s data", testItemKey)
+	}
+
+	if !m.ItemExists(testItemKey) {
+		t.Fatalf("%s item should exist after a successful save operation", testItemKey)
+	}
+
+	loadedData, err := m.LoadItem(testItemKey)
+	if err != nil {
+		t.Fatalf("loading %s error: %v", testItemKey, err)
+	}
+
+	if !bytes.Equal(data, loadedData) {
+		t.Fatalf("saved and loaded data mismatch:\nwant: %q\n have: %q", string(data), string(loadedData))
+	}
+
+	// Now we're deleting an existing item.
+	if err := m.DeleteItem(testItemKey); err != nil {
+		t.Fatalf("delete should never result in an error here (got %v)", err)
+	}
+
+	if m.ItemExists(testItemKey) {
+		t.Fatalf("%s item should not exist after a successful delete operation", testItemKey)
+	}
+}

gdata_unix.go

@@ -38,6 +38,14 @@ func (m *dataManager) SaveData(itemKey string, data []byte) error {
 	return os.WriteFile(m.DataPath(itemKey), data, 0o666)
 }
 
+func (m *dataManager) DeleteData(itemKey string) error {
+	itemPath := m.DataPath(itemKey)
+	if !fileExists(itemPath) {
+		return nil
+	}
+	return os.Remove(itemPath)
+}
+
 func (m *dataManager) LoadData(itemKey string) ([]byte, error) {
 	itemPath := m.DataPath(itemKey)
 	if !fileExists(itemPath) {

gdata_windows.go

@@ -37,6 +37,14 @@ func (m *dataManager) SaveData(itemKey string, data []byte) error {
 	return os.WriteFile(m.DataPath(itemKey), data, 0o666)
 }
 
+func (m *dataManager) DeleteData(itemKey string) error {
+	itemPath := m.DataPath(itemKey)
+	if !fileExists(itemPath) {
+		return nil
+	}
+	return os.Remove(itemPath)
+}
+
 func (m *dataManager) LoadData(itemKey string) ([]byte, error) {
 	itemPath := m.DataPath(itemKey)
 	if !fileExists(itemPath) {