tools/llvm-objcopy/Buffer.h

   1 //===- Buffer.h -------------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_TOOLS_OBJCOPY_BUFFER_H
  10 #define LLVM_TOOLS_OBJCOPY_BUFFER_H
  11
  12 #include "llvm/ADT/StringRef.h"
  13 #include "llvm/Support/FileOutputBuffer.h"
  14 #include "llvm/Support/MemoryBuffer.h"
  15 #include <memory>
  16
  17 namespace llvm {
  18 namespace objcopy {
  19
  20 // The class Buffer abstracts out the common interface of FileOutputBuffer and
  21 // WritableMemoryBuffer so that the hierarchy of Writers depends on this
  22 // abstract interface and doesn't depend on a particular implementation.
  23 // TODO: refactor the buffer classes in LLVM to enable us to use them here
  24 // directly.
  25 class Buffer {
  26   StringRef Name;
  27
  28 public:
  29   virtual ~Buffer();
  30   virtual Error allocate(size_t Size) = 0;
  31   virtual uint8_t *getBufferStart() = 0;
  32   virtual Error commit() = 0;
  33
  34   explicit Buffer(StringRef Name) : Name(Name) {}
  35   StringRef getName() const { return Name; }
  36 };
  37
  38 class FileBuffer : public Buffer {
  39   std::unique_ptr<FileOutputBuffer> Buf;
  40   // Indicates that allocate(0) was called, and commit() should create or
  41   // truncate a file instead of using a FileOutputBuffer.
  42   bool EmptyFile = false;
  43
  44 public:
  45   Error allocate(size_t Size) override;
  46   uint8_t *getBufferStart() override;
  47   Error commit() override;
  48
  49   explicit FileBuffer(StringRef FileName) : Buffer(FileName) {}
  50 };
  51
  52 class MemBuffer : public Buffer {
  53   std::unique_ptr<WritableMemoryBuffer> Buf;
  54
  55 public:
  56   Error allocate(size_t Size) override;
  57   uint8_t *getBufferStart() override;
  58   Error commit() override;
  59
  60   explicit MemBuffer(StringRef Name) : Buffer(Name) {}
  61
  62   std::unique_ptr<WritableMemoryBuffer> releaseMemoryBuffer();
  63 };
  64
  65 } // end namespace objcopy
  66 } // end namespace llvm
  67
  68 #endif // LLVM_TOOLS_OBJCOPY_BUFFER_H