Split CFDE_CSSTextBuf in two.

For the external buffer use case, use a CFDE_CSSExtTextBuf instead. With
the split, both text buffer implementations are simpler now. As a
result, it becomes obvious where it never fails. Adjust callers
accordingly.

Change-Id: I7b53d36593172487b8c939e6a55af2437ea4ee5a
Reviewed-on: https://pdfium-review.googlesource.com/6932
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>

1 files changed, 13 insertions, 53 deletions

diff --git a/xfa/fde/css/cfde_csstextbuf.cpp b/xfa/fde/css/cfde_csstextbuf.cpp
index 8ccdca9fed..0d8ba2d6ce 100644
--- a/xfa/fde/css/cfde_csstextbuf.cpp
+++ b/xfa/fde/css/cfde_csstextbuf.cpp
@@ -6,69 +6,39 @@
 
 #include "xfa/fde/css/cfde_csstextbuf.h"
 
-#include "third_party/base/stl_util.h"
+#include "core/fxcrt/fx_memory.h"
 
 CFDE_CSSTextBuf::CFDE_CSSTextBuf()
-    : m_bExtBuf(false),
-      m_pExtBuffer(nullptr),
-      m_pBuffer(nullptr),
-      m_iBufLen(0),
-      m_iDatLen(0),
-      m_iDatPos(0) {}
+    : m_pBuffer(nullptr), m_iBufLen(0), m_iDatLen(0) {}
 
 CFDE_CSSTextBuf::~CFDE_CSSTextBuf() {
-  Reset();
+  FX_Free(m_pBuffer);
+  m_pBuffer = nullptr;
+  m_iDatLen = m_iBufLen;
 }
 
-void CFDE_CSSTextBuf::AttachBuffer(const wchar_t* pBuffer, int32_t iBufLen) {
-  Reset();
-  m_pExtBuffer = pBuffer;
-  m_iDatLen = m_iBufLen = iBufLen;
-  m_bExtBuf = true;
+void CFDE_CSSTextBuf::InitWithSize(int32_t iAllocSize) {
+  ExpandBuf(iAllocSize);
 }
 
-bool CFDE_CSSTextBuf::EstimateSize(int32_t iAllocSize) {
-  ASSERT(iAllocSize > 0);
-  Clear();
-  m_bExtBuf = false;
-  return ExpandBuf(iAllocSize);
-}
-
-bool CFDE_CSSTextBuf::AppendChar(wchar_t wch) {
-  if (m_iDatLen >= m_iBufLen && !ExpandBuf(m_iBufLen * 2))
-    return false;
+void CFDE_CSSTextBuf::AppendChar(wchar_t wch) {
+  if (m_iDatLen >= m_iBufLen)
+    ExpandBuf(m_iBufLen * 2);
 
-  ASSERT(!m_bExtBuf);
   m_pBuffer[m_iDatLen++] = wch;
-  return true;
-}
-
-void CFDE_CSSTextBuf::Reset() {
-  if (!m_bExtBuf) {
-    FX_Free(m_pBuffer);
-    m_pBuffer = nullptr;
-  }
-  m_iDatPos = m_iDatLen = m_iBufLen;
 }
 
 int32_t CFDE_CSSTextBuf::TrimEnd() {
-  ASSERT(!m_bExtBuf);
   while (m_iDatLen > 0 && m_pBuffer[m_iDatLen - 1] <= ' ')
     --m_iDatLen;
   AppendChar(0);
   return --m_iDatLen;
 }
 
-const wchar_t* CFDE_CSSTextBuf::GetBuffer() const {
-  return m_bExtBuf ? m_pExtBuffer : m_pBuffer;
-}
-
-bool CFDE_CSSTextBuf::ExpandBuf(int32_t iDesiredSize) {
-  if (m_bExtBuf)
-    return false;
-
+void CFDE_CSSTextBuf::ExpandBuf(int32_t iDesiredSize) {
+  ASSERT(iDesiredSize > 0);
   if (m_pBuffer && m_iBufLen == iDesiredSize)
-    return true;
+    return;
 
   if (m_pBuffer)
     m_pBuffer = FX_Realloc(wchar_t, m_pBuffer, iDesiredSize);
@@ -76,14 +46,4 @@ bool CFDE_CSSTextBuf::ExpandBuf(int32_t iDesiredSize) {
     m_pBuffer = FX_Alloc(wchar_t, iDesiredSize);
 
   m_iBufLen = iDesiredSize;
-  return true;
-}
-
-void CFDE_CSSTextBuf::Subtract(int32_t iStart, int32_t iLength) {
-  ASSERT(iStart >= 0 && iLength >= 0);
-  ASSERT(!m_bExtBuf);
-
-  iLength = pdfium::clamp(iLength, 0, m_iDatLen - iStart);
-  memmove(m_pBuffer, m_pBuffer + iStart, iLength * sizeof(wchar_t));
-  m_iDatLen = iLength;
 }