pdf/pdfium/pdfium_api_string_buffer_adapter.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 PDF_PDFIUM_PDFIUM_API_STRING_BUFFER_ADAPTER_H_
   6 #define PDF_PDFIUM_PDFIUM_API_STRING_BUFFER_ADAPTER_H_
   7
   8 #include "base/basictypes.h"
   9
  10 namespace chrome_pdf {
  11
  12 // Helper to deal with the fact that many PDFium APIs write the null-terminator
  13 // into string buffers that are passed to them, but the PDF plugin likes to pass
  14 // in std::strings / base::string16s, where one should not count on the internal
  15 // string buffers to be null-terminated.
  16
  17 template <class StringType>
  18 class PDFiumAPIStringBufferAdapter {
  19  public:
  20   // |str| is the string to write into.
  21   // |expected_size| is the number of characters the PDFium API will write,
  22   // including the null-terminator. It should be at least 1.
  23   // |check_expected_size| whether to check the actual number of characters
  24   // written into |str| against |expected_size| when calling Close().
  25   PDFiumAPIStringBufferAdapter(StringType* str,
  26                                size_t expected_size,
  27                                bool check_expected_size);
  28   ~PDFiumAPIStringBufferAdapter();
  29
  30   // Returns a pointer to |str_|'s buffer. The buffer's size is large enough to
  31   // hold |expected_size_| + 1 characters, so the PDFium API that uses the
  32   // pointer has space to write a null-terminator.
  33   void* GetData();
  34
  35   // Resizes |str_| to |actual_size| - 1 characters, thereby removing the extra
  36   // null-terminator. This must be called prior to the adapter's destruction.
  37   // The pointer returned by GetData() should be considered invalid.
  38   void Close(int actual_size);
  39   void Close(size_t actual_size);
  40
  41  private:
  42   StringType* const str_;
  43   void* const data_;
  44   const size_t expected_size_;
  45   const bool check_expected_size_;
  46   bool is_closed_;
  47
  48   DISALLOW_COPY_AND_ASSIGN(PDFiumAPIStringBufferAdapter);
  49 };
  50
  51 }  // namespace chrome_pdf
  52
  53 #endif  // PDF_PDFIUM_PDFIUM_API_STRING_BUFFER_ADAPTER_H_