Extract test subclasses of IFX_SeekableReadStream

There are multiple instances of subclasses that either act as an
invalid stream or one backed by a memory buffer. Merging all of these
into two shared stream classes and removing the others.

BUG=pdfium:911

Change-Id: I264602808c6dc0e5c878da462a5e00883fe43e51
Reviewed-on: https://pdfium-review.googlesource.com/15093
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>

6 files changed, 67 insertions, 106 deletions

diff --git a/core/fpdfapi/parser/cpdf_object_avail_unittest.cpp b/core/fpdfapi/parser/cpdf_object_avail_unittest.cpp
index 1a8c6d5d14..5c3da70530 100644
--- a/core/fpdfapi/parser/cpdf_object_avail_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_object_avail_unittest.cpp
@@ -14,27 +14,12 @@
 #include "core/fpdfapi/parser/cpdf_reference.h"
 #include "core/fpdfapi/parser/cpdf_string.h"
 #include "core/fxcrt/fx_stream.h"
+#include "testing/fx_string_testhelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/base/ptr_util.h"
 
 namespace {
 
-class InvalidReader : public IFX_SeekableReadStream {
- public:
-  template <typename T, typename... Args>
-  friend RetainPtr<T> pdfium::MakeRetain(Args&&... args);
-
-  // IFX_SeekableReadStream overrides:
-  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
-    return false;
-  }
-  FX_FILESIZE GetSize() override { return 100; }
-
- private:
-  InvalidReader() {}
-  ~InvalidReader() override {}
-};
-
 class TestReadValidator : public CPDF_ReadValidator {
  public:
   template <typename T, typename... Args>
@@ -44,7 +29,9 @@ class TestReadValidator : public CPDF_ReadValidator {
 
  protected:
   TestReadValidator()
-      : CPDF_ReadValidator(pdfium::MakeRetain<InvalidReader>(), nullptr) {}
+      : CPDF_ReadValidator(
+            pdfium::MakeRetain<CFX_InvalidSeekableReadStream>(100),
+            nullptr) {}
   ~TestReadValidator() override {}
 };
 
diff --git a/core/fpdfapi/parser/cpdf_page_object_avail_unittest.cpp b/core/fpdfapi/parser/cpdf_page_object_avail_unittest.cpp
index 1e83e80d32..14ba0e3273 100644
--- a/core/fpdfapi/parser/cpdf_page_object_avail_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_page_object_avail_unittest.cpp
@@ -15,26 +15,12 @@
 #include "core/fpdfapi/parser/cpdf_reference.h"
 #include "core/fpdfapi/parser/cpdf_string.h"
 #include "core/fxcrt/fx_stream.h"
+#include "testing/fx_string_testhelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/base/ptr_util.h"
 
 namespace {
 
-class InvalidReader : public IFX_SeekableReadStream {
- public:
-  template <typename T, typename... Args>
-  friend RetainPtr<T> pdfium::MakeRetain(Args&&... args);
-
-  // IFX_SeekableReadStream overrides:
-  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
-    return false;
-  }
-  FX_FILESIZE GetSize() override { return 100; }
-
- private:
-  InvalidReader() {}
-  ~InvalidReader() override {}
-};
 
 class TestReadValidator : public CPDF_ReadValidator {
  public:
@@ -45,7 +31,9 @@ class TestReadValidator : public CPDF_ReadValidator {
 
  protected:
   TestReadValidator()
-      : CPDF_ReadValidator(pdfium::MakeRetain<InvalidReader>(), nullptr) {}
+      : CPDF_ReadValidator(
+            pdfium::MakeRetain<CFX_InvalidSeekableReadStream>(100),
+            nullptr) {}
   ~TestReadValidator() override {}
 };
 
diff --git a/core/fpdfapi/parser/cpdf_parser_unittest.cpp b/core/fpdfapi/parser/cpdf_parser_unittest.cpp
index b3352975a9..53e1434141 100644
--- a/core/fpdfapi/parser/cpdf_parser_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_parser_unittest.cpp
@@ -10,34 +10,10 @@
 #include "core/fxcrt/fx_extension.h"
 #include "core/fxcrt/fx_stream.h"
 #include "core/fxcrt/retain_ptr.h"
+#include "testing/fx_string_testhelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/utils/path_service.h"
 
-// Provide a way to read test data from a buffer instead of a file.
-class CFX_TestBufferRead : public IFX_SeekableReadStream {
- public:
-  template <typename T, typename... Args>
-  friend RetainPtr<T> pdfium::MakeRetain(Args&&... args);
-
-  // IFX_SeekableReadStream:
-  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
-    if (offset < 0 || offset + size > total_size_)
-      return false;
-
-    memcpy(buffer, buffer_ + offset, size);
-    return true;
-  }
-
-  FX_FILESIZE GetSize() override { return (FX_FILESIZE)total_size_; };
-
- protected:
-  CFX_TestBufferRead(const unsigned char* buffer_in, size_t buf_size)
-      : buffer_(buffer_in), total_size_(buf_size) {}
-
-  const unsigned char* buffer_;
-  size_t total_size_;
-};
-
 // A wrapper class to help test member functions of CPDF_Parser.
 class CPDF_TestParser : public CPDF_Parser {
  public:
@@ -59,8 +35,8 @@ class CPDF_TestParser : public CPDF_Parser {
   // Setup reading from a buffer and initial states.
   bool InitTestFromBuffer(const unsigned char* buffer, size_t len) {
     // For the test file, the header is set at the beginning.
-    m_pSyntax->InitParser(pdfium::MakeRetain<CFX_TestBufferRead>(buffer, len),
-                          0);
+    m_pSyntax->InitParser(
+        pdfium::MakeRetain<CFX_BufferSeekableReadStream>(buffer, len), 0);
     return true;
   }
 
diff --git a/core/fpdfapi/parser/cpdf_read_validator_unittest.cpp b/core/fpdfapi/parser/cpdf_read_validator_unittest.cpp
index c6007a6c31..308704f762 100644
--- a/core/fpdfapi/parser/cpdf_read_validator_unittest.cpp
+++ b/core/fpdfapi/parser/cpdf_read_validator_unittest.cpp
@@ -10,6 +10,7 @@
 
 #include "core/fxcrt/cfx_memorystream.h"
 #include "core/fxcrt/fx_stream.h"
+#include "testing/fx_string_testhelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
@@ -62,22 +63,6 @@ class MockDownloadHints : public CPDF_DataAvail::DownloadHints {
   std::pair<FX_FILESIZE, FX_FILESIZE> last_requested_range_;
 };
 
-class InvalidReader : public IFX_SeekableReadStream {
- public:
-  template <typename T, typename... Args>
-  friend RetainPtr<T> pdfium::MakeRetain(Args&&... args);
-
-  // IFX_SeekableReadStream overrides:
-  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
-    return false;
-  }
-  FX_FILESIZE GetSize() override { return kTestDataSize; }
-
- private:
-  InvalidReader() {}
-  ~InvalidReader() override {}
-};
-
 }  // namespace
 
 TEST(CPDF_ReadValidatorTest, UnavailableData) {
@@ -149,7 +134,7 @@ TEST(CPDF_ReadValidatorTest, UnavailableDataWithHints) {
 }
 
 TEST(CPDF_ReadValidatorTest, ReadError) {
-  auto file = pdfium::MakeRetain<InvalidReader>();
+  auto file = pdfium::MakeRetain<CFX_InvalidSeekableReadStream>(kTestDataSize);
   auto validator = pdfium::MakeRetain<CPDF_ReadValidator>(file, nullptr);
 
   static const uint32_t kBufferSize = 3 * 1000;
@@ -182,7 +167,7 @@ TEST(CPDF_ReadValidatorTest, IntOverflow) {
 TEST(CPDF_ReadValidatorTest, Session) {
   std::vector<uint8_t> test_data(kTestDataSize);
 
-  auto file = pdfium::MakeRetain<InvalidReader>();
+  auto file = pdfium::MakeRetain<CFX_InvalidSeekableReadStream>(kTestDataSize);
   MockFileAvail file_avail;
   MockDownloadHints hints;
   auto validator = pdfium::MakeRetain<CPDF_ReadValidator>(file, &file_avail);
@@ -220,7 +205,7 @@ TEST(CPDF_ReadValidatorTest, Session) {
 TEST(CPDF_ReadValidatorTest, SessionReset) {
   std::vector<uint8_t> test_data(kTestDataSize);
 
-  auto file = pdfium::MakeRetain<InvalidReader>();
+  auto file = pdfium::MakeRetain<CFX_InvalidSeekableReadStream>(kTestDataSize);
   MockFileAvail file_avail;
   MockDownloadHints hints;
   auto validator = pdfium::MakeRetain<CPDF_ReadValidator>(file, &file_avail);
diff --git a/testing/fx_string_testhelpers.h b/testing/fx_string_testhelpers.h
index 34ac69dab4..5a269a3cf6 100644
--- a/testing/fx_string_testhelpers.h
+++ b/testing/fx_string_testhelpers.h
@@ -8,8 +8,58 @@
 #include <ostream>
 
 #include "core/fxcrt/cfx_datetime.h"
+#include "core/fxcrt/fx_stream.h"
 
 // Output stream operator so GTEST macros work with CFX_DateTime objects.
 std::ostream& operator<<(std::ostream& os, const CFX_DateTime& dt);
 
+class CFX_InvalidSeekableReadStream : public IFX_SeekableReadStream {
+ public:
+  template <typename T, typename... Args>
+  friend RetainPtr<T> pdfium::MakeRetain(Args&&... args);
+
+  // IFX_SeekableReadStream overrides:
+  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
+    return false;
+  }
+  FX_FILESIZE GetSize() override { return data_size_; }
+
+ private:
+  explicit CFX_InvalidSeekableReadStream(FX_FILESIZE data_size)
+      : data_size_(data_size) {}
+
+  FX_FILESIZE data_size_;
+};
+
+class CFX_BufferSeekableReadStream : public IFX_SeekableReadStream {
+ public:
+  template <typename T, typename... Args>
+  friend RetainPtr<T> pdfium::MakeRetain(Args&&... args);
+
+  // IFX_SeekableReadStream:
+  bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
+    if (offset < 0 || static_cast<size_t>(offset) >= data_size_)
+      return false;
+
+    if (static_cast<size_t>(offset) + size > data_size_)
+      size = data_size_ - static_cast<size_t>(offset);
+    if (size == 0)
+      return false;
+
+    memcpy(buffer, data_ + offset, size);
+    return true;
+  }
+
+  FX_FILESIZE GetSize() override {
+    return static_cast<FX_FILESIZE>(data_size_);
+  }
+
+ private:
+  CFX_BufferSeekableReadStream(const unsigned char* src, size_t src_size)
+      : data_(src), data_size_(src_size) {}
+
+  const unsigned char* data_;
+  size_t data_size_;
+};
+
 #endif  // TESTING_FX_STRING_TESTHELPERS_H_
diff --git a/testing/libfuzzer/xfa_codec_fuzzer.h b/testing/libfuzzer/xfa_codec_fuzzer.h
index 5193a8930f..a590596dcf 100644
--- a/testing/libfuzzer/xfa_codec_fuzzer.h
+++ b/testing/libfuzzer/xfa_codec_fuzzer.h
@@ -13,8 +13,8 @@
 #include "core/fxcodec/codec/ccodec_progressivedecoder.h"
 #include "core/fxcodec/codec/ccodec_tiffmodule.h"
 #include "core/fxcodec/fx_codec.h"
-#include "core/fxcrt/fx_stream.h"
 #include "core/fxge/dib/cfx_dibitmap.h"
+#include "testing/fx_string_testhelpers.h"
 #include "third_party/base/ptr_util.h"
 
 class XFACodecFuzzer {
@@ -28,7 +28,7 @@ class XFACodecFuzzer {
 
     std::unique_ptr<CCodec_ProgressiveDecoder> decoder =
         mgr->CreateProgressiveDecoder();
-    auto source = pdfium::MakeRetain<Reader>(data, size);
+    auto source = pdfium::MakeRetain<CFX_BufferSeekableReadStream>(data, size);
     FXCODEC_STATUS status = decoder->LoadImageInfo(source, type, nullptr, true);
     if (status != FXCODEC_STATUS_FRAME_READY)
       return 0;
@@ -49,31 +49,6 @@ class XFACodecFuzzer {
 
     return 0;
   }
-
- private:
-  class Reader : public IFX_SeekableReadStream {
-   public:
-    Reader(const uint8_t* data, size_t size) : m_data(data), m_size(size) {}
-    ~Reader() {}
-
-    bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override {
-      if (offset < 0 || static_cast<size_t>(offset) >= m_size)
-        return false;
-      if (offset + size > m_size)
-        size = m_size - offset;
-      if (size == 0)
-        return false;
-
-      memcpy(buffer, m_data + offset, size);
-      return true;
-    }
-
-    FX_FILESIZE GetSize() override { return static_cast<FX_FILESIZE>(m_size); }
-
-   private:
-    const uint8_t* const m_data;
-    const size_t m_size;
-  };
 };
 
 #endif  // TESTING_LIBFUZZER_XFA_CODEC_FUZZER_H_