refactoring: introduce MappedFileFragment

Change-Id: I97b0c1131711ed0ac13ab33e3357e99e0b6b1a4e

linker/linker_mapped_file_fragment.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef LINKER_MAPPED_FILE_FRAGMENT_H
+#define LINKER_MAPPED_FILE_FRAGMENT_H
+
+#include <unistd.h>
+
+#include "private/bionic_macros.h"
+
+class MappedFileFragment {
+ public:
+  MappedFileFragment();
+  ~MappedFileFragment();
+
+  bool Map(int fd, off64_t base_offset, size_t elf_offset, size_t size);
+
+  void* data() const { return data_; }
+  size_t size() const { return size_; }
+ private:
+  void* map_start_;
+  size_t map_size_;
+  void* data_;
+  size_t size_;
+
+  DISALLOW_COPY_AND_ASSIGN(MappedFileFragment);
+};
+
+#endif /* LINKER_MAPPED_FILE_FRAGMENT_H */