Revert "Return pdfium::span<char> from ByteString::GetBuffer()."

This reverts commit 80a6cbe0a427e155de8555bc867af745d10f9777.
Reason for revert: too many abrts in beta branch.

TBR: dsinclair@chromium.org
Bug: 832557, 832978, 832992, 833062, 833097
Change-Id: I7d511dbb224ddc644be96ea2f3770ad6f73debf5
Reviewed-on: https://pdfium-review.googlesource.com/30792
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

4 files changed, 35 insertions, 49 deletions

diff --git a/core/fxcrt/bytestring.cpp b/core/fxcrt/bytestring.cpp
index 872de065ba..f5687c591e 100644
--- a/core/fxcrt/bytestring.cpp
+++ b/core/fxcrt/bytestring.cpp
@@ -18,7 +18,6 @@
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxcrt/string_pool_template.h"
 #include "third_party/base/numerics/safe_math.h"
-#include "third_party/base/span.h"
 #include "third_party/base/stl_util.h"
 
 template class fxcrt::StringDataTemplate<char>;
@@ -82,12 +81,9 @@ ByteString GetByteString(uint16_t codepage, const WideStringView& wstr) {
     return ByteString();
 
   ByteString bstr;
-  {
-    // Span's lifetime must end before ReleaseBuffer() below.
-    pdfium::span<char> dest_buf = bstr.GetBuffer(dest_len);
-    FXSYS_WideCharToMultiByte(codepage, 0, wstr.unterminated_c_str(), src_len,
-                              dest_buf.data(), dest_len, nullptr, nullptr);
-  }
+  char* dest_buf = bstr.GetBuffer(dest_len);
+  FXSYS_WideCharToMultiByte(codepage, 0, wstr.unterminated_c_str(), src_len,
+                            dest_buf, dest_len, nullptr, nullptr);
   bstr.ReleaseBuffer(dest_len);
   return bstr;
 }
@@ -124,21 +120,19 @@ ByteString ByteString::FormatV(const char* pFormat, va_list argList) {
   va_end(argListCopy);
 
   if (nMaxLen <= 0)
-    return ByteString();
+    return "";
 
   ByteString ret;
-  {
-    // Span's lifetime must end before ReleaseBuffer() below.
-    pdfium::span<char> buf = ret.GetBuffer(nMaxLen);
-
+  char* buf = ret.GetBuffer(nMaxLen);
+  if (buf) {
     // In the following two calls, there's always space in the buffer for
     // a terminating NUL that's not included in nMaxLen.
-    memset(buf.data(), 0, nMaxLen + 1);
+    memset(buf, 0, nMaxLen + 1);
     va_copy(argListCopy, argList);
-    vsnprintf(buf.data(), nMaxLen + 1, pFormat, argListCopy);
+    vsnprintf(buf, nMaxLen + 1, pFormat, argListCopy);
     va_end(argListCopy);
+    ret.ReleaseBuffer(ret.GetStringLength());
   }
-  ret.ReleaseBuffer(ret.GetStringLength());
   return ret;
 }
 
@@ -425,29 +419,29 @@ void ByteString::Reserve(size_t len) {
   GetBuffer(len);
 }
 
-pdfium::span<char> ByteString::GetBuffer(size_t nMinBufLength) {
+char* ByteString::GetBuffer(size_t nMinBufLength) {
   if (!m_pData) {
     if (nMinBufLength == 0)
-      return pdfium::span<char>();
+      return nullptr;
 
     m_pData.Reset(StringData::Create(nMinBufLength));
     m_pData->m_nDataLength = 0;
     m_pData->m_String[0] = 0;
-    return pdfium::span<char>(m_pData->m_String, m_pData->m_nAllocLength);
+    return m_pData->m_String;
   }
 
   if (m_pData->CanOperateInPlace(nMinBufLength))
-    return pdfium::span<char>(m_pData->m_String, m_pData->m_nAllocLength);
+    return m_pData->m_String;
 
   nMinBufLength = std::max(nMinBufLength, m_pData->m_nDataLength);
   if (nMinBufLength == 0)
-    return pdfium::span<char>();
+    return nullptr;
 
   RetainPtr<StringData> pNewData(StringData::Create(nMinBufLength));
   pNewData->CopyContents(*m_pData);
   pNewData->m_nDataLength = m_pData->m_nDataLength;
   m_pData.Swap(pNewData);
-  return pdfium::span<char>(m_pData->m_String, m_pData->m_nAllocLength);
+  return m_pData->m_String;
 }
 
 size_t ByteString::Delete(size_t index, size_t count) {
diff --git a/core/fxcrt/bytestring.h b/core/fxcrt/bytestring.h
index 247238573d..ccb539b2ef 100644
--- a/core/fxcrt/bytestring.h
+++ b/core/fxcrt/bytestring.h
@@ -17,7 +17,6 @@
 #include "core/fxcrt/string_data_template.h"
 #include "core/fxcrt/string_view_template.h"
 #include "third_party/base/optional.h"
-#include "third_party/base/span.h"
 
 namespace fxcrt {
 
@@ -154,10 +153,7 @@ class ByteString {
   size_t Delete(size_t index, size_t count = 1);
 
   void Reserve(size_t len);
-
-  // Note: any modification of the string (including ReleaseBuffer()) may
-  // invalidate the span, which must not outlive its buffer.
-  pdfium::span<char> GetBuffer(size_t len);
+  char* GetBuffer(size_t len);
   void ReleaseBuffer(size_t len);
 
   ByteString Mid(size_t first, size_t count) const;
diff --git a/core/fxcrt/bytestring_unittest.cpp b/core/fxcrt/bytestring_unittest.cpp
index d030535edd..f7e1559af9 100644
--- a/core/fxcrt/bytestring_unittest.cpp
+++ b/core/fxcrt/bytestring_unittest.cpp
@@ -843,23 +843,22 @@ TEST(ByteString, Reserve) {
 }
 
 TEST(ByteString, GetBuffer) {
-  ByteString str1;
   {
-    pdfium::span<char> buffer = str1.GetBuffer(12);
+    ByteString str;
+    char* buffer = str.GetBuffer(12);
     // NOLINTNEXTLINE(runtime/printf)
-    strcpy(buffer.data(), "clams");
+    strcpy(buffer, "clams");
+    str.ReleaseBuffer(str.GetStringLength());
+    EXPECT_EQ("clams", str);
   }
-  str1.ReleaseBuffer(str1.GetStringLength());
-  EXPECT_EQ("clams", str1);
-
-  ByteString str2("cl");
   {
-    pdfium::span<char> buffer = str2.GetBuffer(12);
+    ByteString str("cl");
+    char* buffer = str.GetBuffer(12);
     // NOLINTNEXTLINE(runtime/printf)
-    strcpy(&buffer[2], "ams");
+    strcpy(buffer + 2, "ams");
+    str.ReleaseBuffer(str.GetStringLength());
+    EXPECT_EQ("clams", str);
   }
-  str2.ReleaseBuffer(str2.GetStringLength());
-  EXPECT_EQ("clams", str2);
 }
 
 TEST(ByteString, ReleaseBuffer) {
diff --git a/core/fxcrt/widestring.cpp b/core/fxcrt/widestring.cpp
index 25f253ea11..a3525593ee 100644
--- a/core/fxcrt/widestring.cpp
+++ b/core/fxcrt/widestring.cpp
@@ -667,21 +667,18 @@ ByteString WideString::UTF8Encode() const {
 }
 
 ByteString WideString::UTF16LE_Encode() const {
-  if (!m_pData)
+  if (!m_pData) {
     return ByteString("\0\0", 2);
-
-  ByteString result;
+  }
   int len = m_pData->m_nDataLength;
-  {
-    // Span's lifetime must end before ReleaseBuffer() below.
-    pdfium::span<char> buffer = result.GetBuffer(len * 2 + 2);
-    for (int i = 0; i < len; i++) {
-      buffer[i * 2] = m_pData->m_String[i] & 0xff;
-      buffer[i * 2 + 1] = m_pData->m_String[i] >> 8;
-    }
-    buffer[len * 2] = 0;
-    buffer[len * 2 + 1] = 0;
+  ByteString result;
+  char* buffer = result.GetBuffer(len * 2 + 2);
+  for (int i = 0; i < len; i++) {
+    buffer[i * 2] = m_pData->m_String[i] & 0xff;
+    buffer[i * 2 + 1] = m_pData->m_String[i] >> 8;
   }
+  buffer[len * 2] = 0;
+  buffer[len * 2 + 1] = 0;
   result.ReleaseBuffer(len * 2 + 2);
   return result;
 }