Make CFX_SeekableStreamProxy a subclass of IFX_SeekableReadStreamchromium/3405

This CL changes CFX_SeekableStreamProxy to be an IFX_SeekableReadStream
subclass.

This is a reland of https://pdfium-review.googlesource.com/c/pdfium/+/30879
after fix bad merge.

Change-Id: Iad58abe7e065541867f202059a944e9be4da5713
Reviewed-on: https://pdfium-review.googlesource.com/31195
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

2 files changed, 13 insertions, 31 deletions

diff --git a/core/fxcrt/xml/cfx_xmlparser.cpp b/core/fxcrt/xml/cfx_xmlparser.cpp
index 7788a42907..bf578291e6 100644
--- a/core/fxcrt/xml/cfx_xmlparser.cpp
+++ b/core/fxcrt/xml/cfx_xmlparser.cpp
@@ -11,6 +11,7 @@
 #include <iterator>
 #include <utility>
 
+#include "core/fxcrt/cfx_seekablestreamproxy.h"
 #include "core/fxcrt/fx_codepage.h"
 #include "core/fxcrt/fx_extension.h"
 #include "core/fxcrt/fx_safe_types.h"
@@ -57,13 +58,10 @@ bool CFX_XMLParser::IsXMLNameChar(wchar_t ch, bool bFirstChar) {
 }
 
 CFX_XMLParser::CFX_XMLParser(CFX_XMLNode* pParent,
-                             const RetainPtr<IFX_SeekableStream>& pStream)
+                             const RetainPtr<IFX_SeekableReadStream>& pStream)
     : m_pParent(pParent),
       m_pChild(nullptr),
-      m_pStream(pdfium::MakeRetain<CFX_SeekableStreamProxy>(pStream)),
       m_iXMLPlaneSize(1024),
-      m_iCurrentPos(0),
-      m_bEOS(false),
       m_Start(0),
       m_End(0),
       m_CurNodeType(FX_XMLNODE_Unknown),
@@ -77,18 +75,19 @@ CFX_XMLParser::CFX_XMLParser(CFX_XMLNode* pParent,
   ASSERT(m_pParent);
   ASSERT(pStream);
 
-  uint16_t wCodePage = m_pStream->GetCodePage();
+  auto proxy = pdfium::MakeRetain<CFX_SeekableStreamProxy>(pStream);
+  uint16_t wCodePage = proxy->GetCodePage();
   if (wCodePage != FX_CODEPAGE_UTF16LE && wCodePage != FX_CODEPAGE_UTF16BE &&
       wCodePage != FX_CODEPAGE_UTF8) {
-    m_pStream->SetCodePage(FX_CODEPAGE_UTF8);
+    proxy->SetCodePage(FX_CODEPAGE_UTF8);
   }
+  m_pStream = proxy;
 
   m_NodeStack.push(m_pParent);
 
   m_iXMLPlaneSize =
       std::min(m_iXMLPlaneSize,
-               pdfium::base::checked_cast<size_t>(m_pStream->GetLength()));
-  m_iCurrentPos = m_pStream->GetBOMLength();
+               pdfium::base::checked_cast<size_t>(m_pStream->GetSize()));
 
   FX_SAFE_SIZE_T alloc_size_safe = m_iXMLPlaneSize;
   alloc_size_safe += 1;  // For NUL.
@@ -217,28 +216,20 @@ FX_XmlSyntaxResult CFX_XMLParser::DoSyntaxParse() {
     return m_syntaxParserResult;
   }
 
-  FX_FILESIZE iStreamLength = m_pStream->GetLength();
-  FX_FILESIZE iPos;
-
   FX_XmlSyntaxResult syntaxParserResult = FX_XmlSyntaxResult::None;
   while (true) {
     if (m_Start >= m_End) {
-      if (m_bEOS || m_iCurrentPos >= iStreamLength) {
+      if (m_pStream->IsEOF()) {
         m_syntaxParserResult = FX_XmlSyntaxResult::EndOfString;
         return m_syntaxParserResult;
       }
-      if (m_pStream->GetPosition() != m_iCurrentPos)
-        m_pStream->Seek(CFX_SeekableStreamProxy::From::Begin, m_iCurrentPos);
 
       size_t buffer_chars =
-          m_pStream->ReadString(m_Buffer.data(), m_iXMLPlaneSize, &m_bEOS);
-      iPos = m_pStream->GetPosition();
+          m_pStream->ReadBlock(m_Buffer.data(), m_iXMLPlaneSize);
       if (buffer_chars == 0) {
-        m_iCurrentPos = iStreamLength;
         m_syntaxParserResult = FX_XmlSyntaxResult::EndOfString;
         return m_syntaxParserResult;
       }
-      m_iCurrentPos = iPos;
       m_Start = 0;
       m_End = buffer_chars;
     }
@@ -665,13 +656,7 @@ FX_XmlSyntaxResult CFX_XMLParser::DoSyntaxParse() {
 }
 
 bool CFX_XMLParser::GetStatus() const {
-  if (!m_pStream)
-    return false;
-
-  int32_t iStreamLength = m_pStream->GetLength();
-  if (iStreamLength < 1)
-    return true;
-  return m_syntaxParserResult != FX_XmlSyntaxResult::Error;
+  return m_pStream && m_syntaxParserResult != FX_XmlSyntaxResult::Error;
 }
 
 void CFX_XMLParser::ParseTextChar(wchar_t character) {
diff --git a/core/fxcrt/xml/cfx_xmlparser.h b/core/fxcrt/xml/cfx_xmlparser.h
index f369453de1..6405b61a64 100644
--- a/core/fxcrt/xml/cfx_xmlparser.h
+++ b/core/fxcrt/xml/cfx_xmlparser.h
@@ -12,14 +12,13 @@
 #include <vector>
 
 #include "core/fxcrt/cfx_blockbuffer.h"
-#include "core/fxcrt/cfx_seekablestreamproxy.h"
 #include "core/fxcrt/fx_string.h"
 #include "core/fxcrt/retain_ptr.h"
 #include "core/fxcrt/xml/cfx_xmlnode.h"
 
 class CFX_XMLElement;
 class CFX_XMLNode;
-class IFX_SeekableStream;
+class IFX_SeekableReadStream;
 
 enum class FX_XmlSyntaxResult {
   None,
@@ -44,7 +43,7 @@ class CFX_XMLParser {
   static bool IsXMLNameChar(wchar_t ch, bool bFirstChar);
 
   CFX_XMLParser(CFX_XMLNode* pParent,
-                const RetainPtr<IFX_SeekableStream>& pStream);
+                const RetainPtr<IFX_SeekableReadStream>& pStream);
   virtual ~CFX_XMLParser();
 
   bool Parse();
@@ -100,11 +99,9 @@ class CFX_XMLParser {
   std::stack<CFX_XMLNode*> m_NodeStack;
   WideString m_ws1;
 
-  RetainPtr<CFX_SeekableStreamProxy> m_pStream;
+  RetainPtr<IFX_SeekableReadStream> m_pStream;
   size_t m_iXMLPlaneSize;
-  FX_FILESIZE m_iCurrentPos;
   std::vector<wchar_t> m_Buffer;
-  bool m_bEOS;
   FX_FILESIZE m_Start;  // Start position in m_Buffer
   FX_FILESIZE m_End;    // End position in m_Buffer
   FX_XMLNODETYPE m_CurNodeType;