Initial QSfera import

Server/vendor/go.etcd.io/bbolt/internal/common/utils.go

@@ -0,0 +1,64 @@
+package common
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"unsafe"
+)
+
+func LoadBucket(buf []byte) *InBucket {
+	return (*InBucket)(unsafe.Pointer(&buf[0]))
+}
+
+func LoadPage(buf []byte) *Page {
+	return (*Page)(unsafe.Pointer(&buf[0]))
+}
+
+func LoadPageMeta(buf []byte) *Meta {
+	return (*Meta)(unsafe.Pointer(&buf[PageHeaderSize]))
+}
+
+func CopyFile(srcPath, dstPath string) error {
+	// Ensure source file exists.
+	_, err := os.Stat(srcPath)
+	if os.IsNotExist(err) {
+		return fmt.Errorf("source file %q not found", srcPath)
+	} else if err != nil {
+		return err
+	}
+
+	// Ensure output file not exist.
+	_, err = os.Stat(dstPath)
+	if err == nil {
+		return fmt.Errorf("output file %q already exists", dstPath)
+	} else if !os.IsNotExist(err) {
+		return err
+	}
+
+	srcDB, err := os.Open(srcPath)
+	if err != nil {
+		return fmt.Errorf("failed to open source file %q: %w", srcPath, err)
+	}
+	defer srcDB.Close()
+	dstDB, err := os.Create(dstPath)
+	if err != nil {
+		return fmt.Errorf("failed to create output file %q: %w", dstPath, err)
+	}
+	defer dstDB.Close()
+	written, err := io.Copy(dstDB, srcDB)
+	if err != nil {
+		return fmt.Errorf("failed to copy database file from %q to %q: %w", srcPath, dstPath, err)
+	}
+
+	srcFi, err := srcDB.Stat()
+	if err != nil {
+		return fmt.Errorf("failed to get source file info %q: %w", srcPath, err)
+	}
+	initialSize := srcFi.Size()
+	if initialSize != written {
+		return fmt.Errorf("the byte copied (%q: %d) isn't equal to the initial db size (%q: %d)", dstPath, written, srcPath, initialSize)
+	}
+
+	return nil
+}