Fix loading page using hint tables.

When linearized document have hint table,
The FPDFAvail_IsPageAvail return true,
but FPDF_LoadPage return nullptr, for non first pages.

This happens, bacause document not use hint tables, to load page.
To fix this, I force save the page's ObjNum in document.

This is restoring of original fix:
https://codereview.chromium.org/2437773003/

Review-Url: https://codereview.chromium.org/2444903002

1 files changed, 166 insertions, 0 deletions

diff --git a/fpdfsdk/fpdf_dataavail_embeddertest.cpp b/fpdfsdk/fpdf_dataavail_embeddertest.cpp
index 70537779fe..47ba54bcde 100644
--- a/fpdfsdk/fpdf_dataavail_embeddertest.cpp
+++ b/fpdfsdk/fpdf_dataavail_embeddertest.cpp
@@ -2,9 +2,160 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <algorithm>
+#include <memory>
+#include <string>
+#include <vector>
+
 #include "public/fpdfview.h"
 #include "testing/embedder_test.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "testing/test_support.h"
+#include "testing/utils/path_service.h"
+
+namespace {
+class TestAsyncLoader : public FX_DOWNLOADHINTS, FX_FILEAVAIL {
+ public:
+  TestAsyncLoader(const std::string& file_name) {
+    std::string file_path;
+    if (!PathService::GetTestFilePath(file_name, &file_path))
+      return;
+    file_contents_ = GetFileContents(file_path.c_str(), &file_length_);
+    if (!file_contents_)
+      return;
+
+    file_access_.m_FileLen = static_cast<unsigned long>(file_length_);
+    file_access_.m_GetBlock = SGetBlock;
+    file_access_.m_Param = this;
+
+    FX_DOWNLOADHINTS::version = 1;
+    FX_DOWNLOADHINTS::AddSegment = SAddSegment;
+
+    FX_FILEAVAIL::version = 1;
+    FX_FILEAVAIL::IsDataAvail = SIsDataAvail;
+  }
+
+  bool IsOpened() const { return !!file_contents_; }
+
+  FPDF_FILEACCESS* file_access() { return &file_access_; }
+  FX_DOWNLOADHINTS* hints() { return this; }
+  FX_FILEAVAIL* file_avail() { return this; }
+
+  const std::vector<std::pair<size_t, size_t>>& requested_segments() const {
+    return requested_segments_;
+  }
+
+  void ClearRequestedSegments() { requested_segments_.clear(); }
+
+  bool is_new_data_available() const { return is_new_data_available_; }
+  void set_is_new_data_available(bool is_new_data_available) {
+    is_new_data_available_ = is_new_data_available;
+  }
+
+ private:
+  void SetDataAvailable(size_t start, size_t size) {
+    if (size == 0)
+      return;
+    const auto range = std::make_pair(start, start + size);
+    if (available_ranges_.empty()) {
+      available_ranges_.insert(range);
+      return;
+    }
+    auto start_it = available_ranges_.upper_bound(range);
+    if (start_it != available_ranges_.begin())
+      --start_it;  // start now points to the key equal or lower than offset.
+    if (start_it->second < range.first)
+      ++start_it;  // start element is entirely before current range, skip it.
+
+    auto end_it = available_ranges_.upper_bound(
+        std::make_pair(range.second, range.second));
+    if (start_it == end_it) {  // No ranges to merge.
+      available_ranges_.insert(range);
+      return;
+    }
+
+    --end_it;
+
+    size_t new_start = std::min<size_t>(start_it->first, range.first);
+    size_t new_end = std::max(end_it->second, range.second);
+
+    available_ranges_.erase(start_it, ++end_it);
+    available_ranges_.insert(std::make_pair(new_start, new_end));
+  }
+
+  bool CheckDataAlreadyAvailable(size_t start, size_t size) const {
+    if (size == 0)
+      return false;
+    const auto range = std::make_pair(start, start + size);
+    auto it = available_ranges_.upper_bound(range);
+    if (it == available_ranges_.begin())
+      return false;  // No ranges includes range.start().
+
+    --it;  // Now it starts equal or before range.start().
+    return it->second >= range.second;
+  }
+
+  int GetBlockImpl(unsigned long pos, unsigned char* pBuf, unsigned long size) {
+    if (!IsDataAvailImpl(pos, size))
+      return 0;
+    const unsigned long end =
+        std::min(static_cast<unsigned long>(file_length_), pos + size);
+    if (end <= pos)
+      return 0;
+    memcpy(pBuf, file_contents_.get() + pos, end - pos);
+    SetDataAvailable(pos, end - pos);
+    return static_cast<int>(end - pos);
+  }
+
+  void AddSegmentImpl(size_t offset, size_t size) {
+    requested_segments_.push_back(std::make_pair(offset, size));
+  }
+
+  bool IsDataAvailImpl(size_t offset, size_t size) {
+    if (offset + size > file_length_)
+      return false;
+    if (is_new_data_available_) {
+      SetDataAvailable(offset, size);
+      return true;
+    }
+    return CheckDataAlreadyAvailable(offset, size);
+  }
+
+  static int SGetBlock(void* param,
+                       unsigned long pos,
+                       unsigned char* pBuf,
+                       unsigned long size) {
+    return static_cast<TestAsyncLoader*>(param)->GetBlockImpl(pos, pBuf, size);
+  }
+
+  static void SAddSegment(FX_DOWNLOADHINTS* pThis, size_t offset, size_t size) {
+    return static_cast<TestAsyncLoader*>(pThis)->AddSegmentImpl(offset, size);
+  }
+
+  static FPDF_BOOL SIsDataAvail(FX_FILEAVAIL* pThis,
+                                size_t offset,
+                                size_t size) {
+    return static_cast<TestAsyncLoader*>(pThis)->IsDataAvailImpl(offset, size);
+  }
+
+  FPDF_FILEACCESS file_access_;
+
+  std::unique_ptr<char, pdfium::FreeDeleter> file_contents_;
+  size_t file_length_;
+  std::vector<std::pair<size_t, size_t>> requested_segments_;
+  bool is_new_data_available_ = true;
+
+  using Range = std::pair<size_t, size_t>;
+  struct range_compare {
+    bool operator()(const Range& lval, const Range& rval) const {
+      return lval.first < rval.first;
+    }
+  };
+  using RangesContainer = std::set<Range, range_compare>;
+  RangesContainer available_ranges_;
+};
+
+}  // namespace
 
 class FPDFDataAvailEmbeddertest : public EmbedderTest {};
 
@@ -19,3 +170,18 @@ TEST_F(FPDFDataAvailEmbeddertest, TrailerAsHexstring) {
   EXPECT_FALSE(OpenDocument("trailer_as_hexstring.pdf"));
   EXPECT_FALSE(FPDFAvail_IsDocAvail(avail_, &hints_));
 }
+
+TEST_F(FPDFDataAvailEmbeddertest, LoadUsingHintTables) {
+  TestAsyncLoader loader("feature_linearized_loading.pdf");
+  avail_ = FPDFAvail_Create(loader.file_avail(), loader.file_access());
+  ASSERT_EQ(PDF_DATA_AVAIL, FPDFAvail_IsDocAvail(avail_, loader.hints()));
+  document_ = FPDFAvail_GetDocument(avail_, nullptr);
+  ASSERT_TRUE(document_);
+  ASSERT_EQ(PDF_DATA_AVAIL, FPDFAvail_IsPageAvail(avail_, 1, loader.hints()));
+
+  // No new data available, to prevent load "Pages" node.
+  loader.set_is_new_data_available(false);
+  FPDF_PAGE page = LoadPage(1);
+  EXPECT_TRUE(page);
+  UnloadPage(page);
+}