Make CFX_ReadOnlyMemoryStream take a span.

Change-Id: Id097320ab2d9b5d1579582e5797e29c701499501
Reviewed-on: https://pdfium-review.googlesource.com/39991
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

4 files changed, 13 insertions, 15 deletions

diff --git a/core/fpdfapi/parser/cfdf_document.cpp b/core/fpdfapi/parser/cfdf_document.cpp
index d37c8d5457..421af48d80 100644
--- a/core/fpdfapi/parser/cfdf_document.cpp
+++ b/core/fpdfapi/parser/cfdf_document.cpp
@@ -32,8 +32,7 @@ std::unique_ptr<CFDF_Document> CFDF_Document::CreateNewDoc() {
 std::unique_ptr<CFDF_Document> CFDF_Document::ParseMemory(
     pdfium::span<const uint8_t> span) {
   auto pDoc = pdfium::MakeUnique<CFDF_Document>();
-  pDoc->ParseStream(
-      pdfium::MakeRetain<CFX_ReadOnlyMemoryStream>(span.data(), span.size()));
+  pDoc->ParseStream(pdfium::MakeRetain<CFX_ReadOnlyMemoryStream>(span));
   return pDoc->m_pRootDict ? std::move(pDoc) : nullptr;
 }
 
diff --git a/core/fpdfdoc/cpdf_metadata.cpp b/core/fpdfdoc/cpdf_metadata.cpp
index b9a92963dd..99fd965452 100644
--- a/core/fpdfdoc/cpdf_metadata.cpp
+++ b/core/fpdfdoc/cpdf_metadata.cpp
@@ -67,8 +67,7 @@ std::vector<UnsupportedFeature> CPDF_Metadata::CheckForSharedForm() const {
   auto pAcc = pdfium::MakeRetain<CPDF_StreamAcc>(stream_.Get());
   pAcc->LoadAllDataFiltered();
 
-  auto stream = pdfium::MakeRetain<CFX_ReadOnlyMemoryStream>(pAcc->GetData(),
-                                                             pAcc->GetSize());
+  auto stream = pdfium::MakeRetain<CFX_ReadOnlyMemoryStream>(pAcc->GetSpan());
   CFX_XMLParser parser(stream);
   std::unique_ptr<CFX_XMLDocument> doc = parser.Parse();
   if (!doc)
diff --git a/core/fxcrt/cfx_readonlymemorystream.cpp b/core/fxcrt/cfx_readonlymemorystream.cpp
index 1d09759208..a01ed2e474 100644
--- a/core/fxcrt/cfx_readonlymemorystream.cpp
+++ b/core/fxcrt/cfx_readonlymemorystream.cpp
@@ -8,14 +8,14 @@
 
 #include "core/fxcrt/fx_safe_types.h"
 
-CFX_ReadOnlyMemoryStream::CFX_ReadOnlyMemoryStream(const uint8_t* pBuf,
-                                                   FX_FILESIZE size)
-    : m_pBuf(pBuf), m_size(size) {}
+CFX_ReadOnlyMemoryStream::CFX_ReadOnlyMemoryStream(
+    pdfium::span<const uint8_t> span)
+    : m_span(span) {}
 
 CFX_ReadOnlyMemoryStream::~CFX_ReadOnlyMemoryStream() = default;
 
 FX_FILESIZE CFX_ReadOnlyMemoryStream::GetSize() {
-  return m_size;
+  return pdfium::base::checked_cast<FX_FILESIZE>(m_span.size());
 }
 
 bool CFX_ReadOnlyMemoryStream::ReadBlock(void* buffer,
@@ -24,11 +24,11 @@ bool CFX_ReadOnlyMemoryStream::ReadBlock(void* buffer,
   if (offset < 0)
     return false;
 
-  FX_SAFE_FILESIZE newPos = pdfium::base::checked_cast<FX_FILESIZE>(size);
-  newPos += offset;
-  if (!newPos.IsValid() || newPos.ValueOrDie() > m_size)
+  FX_SAFE_SIZE_T pos = size;
+  pos += offset;
+  if (!pos.IsValid() || pos.ValueOrDie() > m_span.size())
     return false;
 
-  memcpy(buffer, m_pBuf + offset, size);
+  memcpy(buffer, &m_span[offset], size);
   return true;
 }
diff --git a/core/fxcrt/cfx_readonlymemorystream.h b/core/fxcrt/cfx_readonlymemorystream.h
index e9d18222a4..a6645b82c7 100644
--- a/core/fxcrt/cfx_readonlymemorystream.h
+++ b/core/fxcrt/cfx_readonlymemorystream.h
@@ -9,6 +9,7 @@
 
 #include "core/fxcrt/fx_stream.h"
 #include "core/fxcrt/retain_ptr.h"
+#include "third_party/base/span.h"
 
 class CFX_ReadOnlyMemoryStream final : public IFX_SeekableReadStream {
  public:
@@ -20,11 +21,10 @@ class CFX_ReadOnlyMemoryStream final : public IFX_SeekableReadStream {
   bool ReadBlock(void* buffer, FX_FILESIZE offset, size_t size) override;
 
  private:
-  CFX_ReadOnlyMemoryStream(const uint8_t* pBuf, FX_FILESIZE size);
+  explicit CFX_ReadOnlyMemoryStream(pdfium::span<const uint8_t> span);
   ~CFX_ReadOnlyMemoryStream() override;
 
-  const uint8_t* const m_pBuf;
-  const FX_FILESIZE m_size;
+  const pdfium::span<const uint8_t> m_span;
 };
 
 #endif  // CORE_FXCRT_CFX_READONLYMEMORYSTREAM_H_