Use pdfium::span<> in CPDF_Encryptor

Provides more lifetime/bounds checking "for free".

Change-Id: Ifaf7a95c0f6f288777cd6ef35996e01b3dc4bc63
Reviewed-on: https://pdfium-review.googlesource.com/32594
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>

3 files changed, 38 insertions, 33 deletions

diff --git a/core/fpdfapi/edit/cpdf_creator.cpp b/core/fpdfapi/edit/cpdf_creator.cpp
index 71237f7915..8a9eb5493e 100644
--- a/core/fpdfapi/edit/cpdf_creator.cpp
+++ b/core/fpdfapi/edit/cpdf_creator.cpp
@@ -164,13 +164,13 @@ bool CPDF_Creator::WriteStream(const CPDF_Object* pStream,
                                uint32_t objnum,
                                CPDF_CryptoHandler* pCrypto) {
   CPDF_FlateEncoder encoder(pStream->AsStream(), pStream != m_pMetadata);
-  CPDF_Encryptor encryptor(pCrypto, objnum, encoder.GetData(),
-                           encoder.GetSize());
+  CPDF_Encryptor encryptor(
+      pCrypto, objnum, pdfium::make_span(encoder.GetData(), encoder.GetSize()));
   if (static_cast<uint32_t>(encoder.GetDict()->GetIntegerFor("Length")) !=
-      encryptor.GetSize()) {
+      encryptor.GetSpan().size()) {
     encoder.CloneDict();
     encoder.GetClonedDict()->SetNewFor<CPDF_Number>(
-        "Length", static_cast<int>(encryptor.GetSize()));
+        "Length", static_cast<int>(encryptor.GetSpan().size()));
   }
 
   if (!WriteDirectObj(objnum, encoder.GetDict(), true) ||
@@ -179,8 +179,9 @@ bool CPDF_Creator::WriteStream(const CPDF_Object* pStream,
   }
 
   // Allow for empty streams.
-  if (encryptor.GetSize() > 0 &&
-      !m_Archive->WriteBlock(encryptor.GetData(), encryptor.GetSize())) {
+  if (encryptor.GetSpan().size() > 0 &&
+      !m_Archive->WriteBlock(encryptor.GetSpan().data(),
+                             encryptor.GetSpan().size())) {
     return false;
   }
 
@@ -224,28 +225,32 @@ bool CPDF_Creator::WriteDirectObj(uint32_t objnum,
           return false;
         break;
       }
-      CPDF_Encryptor encryptor(GetCryptoHandler(), objnum,
-                               reinterpret_cast<const uint8_t*>(str.c_str()),
-                               str.GetLength());
+      CPDF_Encryptor encryptor(
+          GetCryptoHandler(), objnum,
+          pdfium::make_span(reinterpret_cast<const uint8_t*>(str.c_str()),
+                            str.GetLength()));
       ByteString content = PDF_EncodeString(
-          ByteString(encryptor.GetData(), encryptor.GetSize()), bHex);
+          ByteString(encryptor.GetSpan().data(), encryptor.GetSpan().size()),
+          bHex);
       if (!m_Archive->WriteString(content.AsStringView()))
         return false;
       break;
     }
     case CPDF_Object::STREAM: {
       CPDF_FlateEncoder encoder(pObj->AsStream(), true);
-      CPDF_Encryptor encryptor(GetCryptoHandler(), objnum, encoder.GetData(),
-                               encoder.GetSize());
+      CPDF_Encryptor encryptor(
+          GetCryptoHandler(), objnum,
+          pdfium::make_span(encoder.GetData(), encoder.GetSize()));
       if (static_cast<uint32_t>(encoder.GetDict()->GetIntegerFor("Length")) !=
-          encryptor.GetSize()) {
+          encryptor.GetSpan().size()) {
         encoder.CloneDict();
         encoder.GetClonedDict()->SetNewFor<CPDF_Number>(
-            "Length", static_cast<int>(encryptor.GetSize()));
+            "Length", static_cast<int>(encryptor.GetSpan().size()));
       }
       if (!WriteDirectObj(objnum, encoder.GetDict(), true) ||
           !m_Archive->WriteString("stream\r\n") ||
-          !m_Archive->WriteBlock(encryptor.GetData(), encryptor.GetSize()) ||
+          !m_Archive->WriteBlock(encryptor.GetSpan().data(),
+                                 encryptor.GetSpan().size()) ||
           !m_Archive->WriteString("\r\nendstream")) {
         return false;
       }
diff --git a/core/fpdfapi/edit/cpdf_encryptor.cpp b/core/fpdfapi/edit/cpdf_encryptor.cpp
index 033df38a48..fd969b8b2c 100644
--- a/core/fpdfapi/edit/cpdf_encryptor.cpp
+++ b/core/fpdfapi/edit/cpdf_encryptor.cpp
@@ -9,21 +9,23 @@
 
 CPDF_Encryptor::CPDF_Encryptor(CPDF_CryptoHandler* pHandler,
                                int objnum,
-                               const uint8_t* src_data,
-                               uint32_t src_size) {
-  if (src_size == 0)
+                               pdfium::span<const uint8_t> src_data) {
+  if (src_data.empty())
     return;
 
   if (!pHandler) {
-    m_pData = src_data;
-    m_dwSize = src_size;
+    m_Span = src_data;
     return;
   }
-  m_dwSize = pHandler->EncryptGetSize(objnum, 0, src_data, src_size);
-  m_pNewBuf.reset(FX_Alloc(uint8_t, m_dwSize));
-  pHandler->EncryptContent(objnum, 0, src_data, src_size, m_pNewBuf.get(),
-                           m_dwSize);
-  m_pData = m_pNewBuf.get();
+
+  uint32_t buf_size =
+      pHandler->EncryptGetSize(objnum, 0, src_data.data(), src_data.size());
+  m_NewBuf.resize(buf_size);
+  pHandler->EncryptContent(objnum, 0, src_data.data(), src_data.size(),
+                           m_NewBuf.data(),
+                           buf_size);  // Updates |buf_size| with actual.
+  m_NewBuf.resize(buf_size);
+  m_Span = m_NewBuf;
 }
 
 CPDF_Encryptor::~CPDF_Encryptor() {}
diff --git a/core/fpdfapi/edit/cpdf_encryptor.h b/core/fpdfapi/edit/cpdf_encryptor.h
index a62a4ebf22..67fd5c4f9b 100644
--- a/core/fpdfapi/edit/cpdf_encryptor.h
+++ b/core/fpdfapi/edit/cpdf_encryptor.h
@@ -9,9 +9,10 @@
 
 #include <stdint.h>
 
-#include <memory>
+#include <vector>
 
 #include "core/fxcrt/fx_memory.h"
+#include "third_party/base/span.h"
 
 class CPDF_CryptoHandler;
 
@@ -19,17 +20,14 @@ class CPDF_Encryptor {
  public:
   CPDF_Encryptor(CPDF_CryptoHandler* pHandler,
                  int objnum,
-                 const uint8_t* src_data,
-                 uint32_t src_size);
+                 pdfium::span<const uint8_t> src_data);
   ~CPDF_Encryptor();
 
-  uint32_t GetSize() const { return m_dwSize; }
-  const uint8_t* GetData() const { return m_pData; }
+  pdfium::span<const uint8_t> GetSpan() const { return m_Span; }
 
  private:
-  const uint8_t* m_pData = nullptr;
-  std::unique_ptr<uint8_t, FxFreeDeleter> m_pNewBuf;
-  uint32_t m_dwSize = 0;
+  std::vector<uint8_t> m_NewBuf;
+  pdfium::span<const uint8_t> m_Span;
 };
 
 #endif  // CORE_FPDFAPI_EDIT_CPDF_ENCRYPTOR_H_