perf(stream): improve file stream range reading and caching mechanism (#1001)

* perf(stream): improve file stream range reading and caching mechanism

* 。

* add bytes_test.go

* fix(stream): handle EOF and buffer reading more gracefully

* 注释

* refactor: update CacheFullAndWriter to accept pointer for UpdateProgress

* update tests

* Update drivers/google_drive/util.go

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: j2rong4cn <36783515+j2rong4cn@users.noreply.github.com>

* 更优雅的克隆Link

* 修复stream已缓存但无法重复读取

* 将Bytes类型重命名为Reader

* 修复栈溢出

* update tests

---------

Signed-off-by: j2rong4cn <36783515+j2rong4cn@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

pkg/buffer/bytes_test.go

@@ -0,0 +1,95 @@
+package buffer
+
+import (
+	"errors"
+	"io"
+	"testing"
+)
+
+func TestReader_ReadAt(t *testing.T) {
+	type args struct {
+		p   []byte
+		off int64
+	}
+	bs := &Reader{}
+	bs.Append([]byte("github.com"))
+	bs.Append([]byte("/"))
+	bs.Append([]byte("OpenList"))
+	bs.Append([]byte("Team/"))
+	bs.Append([]byte("OpenList"))
+	tests := []struct {
+		name string
+		b    *Reader
+		args args
+		want func(a args, n int, err error) error
+	}{
+		{
+			name: "readAt len 10 offset 0",
+			b:    bs,
+			args: args{
+				p:   make([]byte, 10),
+				off: 0,
+			},
+			want: func(a args, n int, err error) error {
+				if n != len(a.p) {
+					return errors.New("read length not match")
+				}
+				if string(a.p) != "github.com" {
+					return errors.New("read content not match")
+				}
+				if err != nil {
+					return err
+				}
+				return nil
+			},
+		},
+		{
+			name: "readAt len 12 offset 11",
+			b:    bs,
+			args: args{
+				p:   make([]byte, 12),
+				off: 11,
+			},
+			want: func(a args, n int, err error) error {
+				if n != len(a.p) {
+					return errors.New("read length not match")
+				}
+				if string(a.p) != "OpenListTeam" {
+					return errors.New("read content not match")
+				}
+				if err != nil {
+					return err
+				}
+				return nil
+			},
+		},
+		{
+			name: "readAt len 50 offset 24",
+			b:    bs,
+			args: args{
+				p:   make([]byte, 50),
+				off: 24,
+			},
+			want: func(a args, n int, err error) error {
+				if n != bs.Len()-int(a.off) {
+					return errors.New("read length not match")
+				}
+				if string(a.p[:n]) != "OpenList" {
+					return errors.New("read content not match")
+				}
+				if err != io.EOF {
+					return errors.New("expect eof")
+				}
+				return nil
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := tt.b.ReadAt(tt.args.p, tt.args.off)
+			if err := tt.want(tt.args, got, err); err != nil {
+				t.Errorf("Bytes.ReadAt() error = %v", err)
+			}
+		})
+	}
+}