chrome/utility/safe_browsing/mac/read_stream.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_UTILITY_SAFE_BROWSING_MAC_READ_STREAM_H_
   6 #define CHROME_UTILITY_SAFE_BROWSING_MAC_READ_STREAM_H_
   7
   8 #include <stdint.h>
   9 #include <unistd.h>
  10
  11 #include "base/macros.h"
  12
  13 namespace safe_browsing {
  14 namespace dmg {
  15
  16 // An interface for reading and seeking over a byte stream.
  17 class ReadStream {
  18  public:
  19   virtual ~ReadStream() {}
  20
  21   // Copies up to |size| bytes into |data|. Returns |true| on success with the
  22   // actual number of bytes written stored in |size|. Returns |false| on error.
  23   // At end-of-stream, returns |true| with |bytes_read| set to 0.
  24   virtual bool Read(uint8_t* data, size_t size, size_t* bytes_read) = 0;
  25
  26   // Calls |Read| but only returns true if the number of bytes read equals
  27   // |size|.
  28   bool ReadExact(uint8_t* data, size_t size);
  29
  30   template <typename T>
  31   bool ReadType(T* t) {
  32     return ReadExact(reinterpret_cast<uint8_t*>(t), sizeof(T));
  33   }
  34
  35   // Seeks the read stream to |offset| from |whence|. |whence| is a POSIX-style
  36   // SEEK_ constant. Returns the resulting offset location, or a negative value
  37   // on failure.
  38   virtual off_t Seek(off_t offset, int whence) = 0;
  39 };
  40
  41 // An implementation of ReadStream backed by a file descriptor. This does not
  42 // take ownership of the file descriptor.
  43 class FileReadStream : public ReadStream {
  44  public:
  45   explicit FileReadStream(int fd);
  46   ~FileReadStream() override;
  47
  48   // ReadStream:
  49   bool Read(uint8_t* data, size_t size, size_t* bytes_read) override;
  50   off_t Seek(off_t offset, int whence) override;
  51
  52  private:
  53   int fd_;
  54
  55   DISALLOW_COPY_AND_ASSIGN(FileReadStream);
  56 };
  57
  58 // An implementation of ReadStream that operates on a byte buffer. This class
  59 // does not take ownership of the underlying byte array.
  60 class MemoryReadStream : public ReadStream {
  61  public:
  62   MemoryReadStream(const uint8_t* data, size_t size);
  63   ~MemoryReadStream() override;
  64
  65   // ReadStream:
  66   bool Read(uint8_t* data, size_t size, size_t* bytes_read) override;
  67   off_t Seek(off_t offset, int whence) override;
  68
  69   const uint8_t* data() const { return data_; }
  70   size_t size() const { return size_; }
  71
  72  protected:
  73   const uint8_t* data_;
  74   size_t size_;
  75   off_t offset_;
  76
  77  private:
  78   DISALLOW_COPY_AND_ASSIGN(MemoryReadStream);
  79 };
  80
  81 }  // namespace dmg
  82 }  // namespace safe_browsing
  83
  84 #endif  // CHROME_UTILITY_SAFE_BROWSING_MAC_READ_STREAM_H_