some library updates and adds support for adblock lists

internal/common/file-operations.go

@@ -0,0 +1,52 @@
+package common
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+func FileExists(path string) bool {
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return false
+	}
+	return true
+}
+
+func ReadFile(path string) ([]byte, error) {
+	var output []byte
+	if !FileExists(path) {
+		return []byte{}, fmt.Errorf("Unable to read file, file does not exist: %s", path)
+	}
+
+	output, err := os.ReadFile(path)
+	if err != nil {
+		return []byte{}, fmt.Errorf("Unable to read file, %v: %s", err, path)
+	}
+	return output, nil
+}
+
+func WriteFile(path string, data []byte) (int, error) {
+	dir := filepath.Dir(path)
+
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return 0, fmt.Errorf("Unable to create parent directory, %v: %s", err, dir)
+	}
+
+	fh, err := os.Create(path)
+	if err != nil {
+		return 0, fmt.Errorf("Unable to open file for writing, %v: %s", err, path)
+	}
+	defer fh.Close()
+
+	bs, err := fh.Write(data)
+	if err != nil {
+		return 0, fmt.Errorf("Unable to write file, %v: %s", err, path)
+	}
+
+	if err := fh.Sync(); err != nil {
+		return 0, fmt.Errorf("Unable to sync file to disk, %v: %s", err, path)
+	}
+
+	return bs, nil
+}