Implement read validator.

The wrapper for IFX_SeekableReadStream.
Which allow us to check data availability on read request
and request downloading of non available data on fly.

Change-Id: I27c66cd58f43f8432f73104cc3f4c980515a9b56
Reviewed-on: https://pdfium-review.googlesource.com/9050
Commit-Queue: Art Snake <art-snake@yandex-team.ru>
Reviewed-by: (OOO Jul 28 - Aug 8) dsinclair <dsinclair@chromium.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/core/fpdfapi/parser/cpdf_read_validator.h b/core/fpdfapi/parser/cpdf_read_validator.h
new file mode 100644
index 0000000000..da8acfe23b
--- /dev/null
+++ b/core/fpdfapi/parser/cpdf_read_validator.h
@@ -0,0 +1,48 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CORE_FPDFAPI_PARSER_CPDF_READ_VALIDATOR_H_
+#define CORE_FPDFAPI_PARSER_CPDF_READ_VALIDATOR_H_
+
+#include "core/fpdfapi/parser/cpdf_data_avail.h"
+
+class CPDF_ReadValidator : public IFX_SeekableReadStream {
+ public:
+  template <typename T, typename... Args>
+  friend CFX_RetainPtr<T> pdfium::MakeRetain(Args&&... args);
+
+  void SetDownloadHints(CPDF_DataAvail::DownloadHints* hints) {
+    hints_ = hints;
+  }
+
+  bool read_error() const { return read_error_; }
+  bool has_unavailable_data() const { return has_unavailable_data_; }
+
+  bool has_read_problems() const {
+    return read_error() || has_unavailable_data();
+  }
+
+  void ResetErrors();
+
+  // IFX_SeekableReadStream overrides:
+  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override;
+  FX_FILESIZE GetSize() override;
+
+ private:
+  CPDF_ReadValidator(const CFX_RetainPtr<IFX_SeekableReadStream>& file_read,
+                     CPDF_DataAvail::FileAvail* file_avail);
+  ~CPDF_ReadValidator() override;
+
+  void ScheduleDownload(FX_FILESIZE offset, size_t size);
+
+  CFX_RetainPtr<IFX_SeekableReadStream> file_read_;
+  CFX_UnownedPtr<CPDF_DataAvail::FileAvail> file_avail_;
+
+  CFX_UnownedPtr<CPDF_DataAvail::DownloadHints> hints_;
+
+  bool read_error_;
+  bool has_unavailable_data_;
+};
+
+#endif  // CORE_FPDFAPI_PARSER_CPDF_READ_VALIDATOR_H_