Add type cast definitions for CPDF_Stream.

This Cl adds ToStream, CPDF_Object::AsStream and CPDF_Object::IsStream and
updates the src to use them as needed.

BUG=pdfium:201
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1402413004 .

7 files changed, 46 insertions, 55 deletions

diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
index 4f54c01ce7..bed3cfbb2c 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp
@@ -913,9 +913,9 @@ FX_BOOL CPDF_IndexedCS::v_Load(CPDF_Document* pDoc, CPDF_Array* pArray) {
 
   if (CPDF_String* pString = pTableObj->AsString()) {
     m_Table = pString->GetString();
-  } else if (pTableObj->GetType() == PDFOBJ_STREAM) {
+  } else if (CPDF_Stream* pStream = pTableObj->AsStream()) {
     CPDF_StreamAcc acc;
-    acc.LoadAllData((CPDF_Stream*)pTableObj, FALSE);
+    acc.LoadAllData(pStream, FALSE);
     m_Table = CFX_ByteStringC(acc.GetData(), acc.GetSize());
   }
   return TRUE;
@@ -1204,8 +1204,8 @@ CPDF_ColorSpace* CPDF_ColorSpace::Load(CPDF_Document* pDoc, CPDF_Object* pObj) {
   if (pObj->IsName())
     return _CSFromName(pObj->GetString());
 
-  if (pObj->GetType() == PDFOBJ_STREAM) {
-    CPDF_Dictionary* pDict = ((CPDF_Stream*)pObj)->GetDict();
+  if (CPDF_Stream* pStream = pObj->AsStream()) {
+    CPDF_Dictionary* pDict = pStream->GetDict();
     if (!pDict)
       return nullptr;
 
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
index 436cca6d99..8656b72023 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp
@@ -470,7 +470,7 @@ CPDF_Image* CPDF_DocPageData::GetImage(CPDF_Object* pImageStream) {
   }
 
   CPDF_Image* pImage = new CPDF_Image(m_pPDFDoc);
-  pImage->LoadImageF((CPDF_Stream*)pImageStream, FALSE);
+  pImage->LoadImageF(pImageStream->AsStream(), FALSE);
 
   CPDF_CountedImage* imageData = new CPDF_CountedImage(pImage);
   m_ImageMap[dwImageObjNum] = imageData;
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
index d66a9efdaa..2d35dd85be 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp
@@ -491,10 +491,10 @@ CPDF_SampledFunc::~CPDF_SampledFunc() {
   FX_Free(m_pDecodeInfo);
 }
 FX_BOOL CPDF_SampledFunc::v_Init(CPDF_Object* pObj) {
-  if (pObj->GetType() != PDFOBJ_STREAM) {
-    return FALSE;
-  }
-  CPDF_Stream* pStream = (CPDF_Stream*)pObj;
+  CPDF_Stream* pStream = pObj->AsStream();
+  if (!pStream)
+    return false;
+
   CPDF_Dictionary* pDict = pStream->GetDict();
   CPDF_Array* pSize = pDict->GetArray(FX_BSTRC("Size"));
   CPDF_Array* pEncode = pDict->GetArray(FX_BSTRC("Encode"));
@@ -632,7 +632,7 @@ class CPDF_PSFunc : public CPDF_Function {
 };
 
 FX_BOOL CPDF_PSFunc::v_Init(CPDF_Object* pObj) {
-  CPDF_Stream* pStream = (CPDF_Stream*)pObj;
+  CPDF_Stream* pStream = pObj->AsStream();
   CPDF_StreamAcc acc;
   acc.LoadAllData(pStream, FALSE);
   return m_PS.Parse((const FX_CHAR*)acc.GetData(), acc.GetSize());
@@ -814,10 +814,8 @@ CPDF_Function* CPDF_Function::Load(CPDF_Object* pFuncObj) {
   }
   CPDF_Function* pFunc = NULL;
   int type;
-  if (pFuncObj->GetType() == PDFOBJ_STREAM) {
-    type = ((CPDF_Stream*)pFuncObj)
-               ->GetDict()
-               ->GetInteger(FX_BSTRC("FunctionType"));
+  if (CPDF_Stream* pStream = pFuncObj->AsStream()) {
+    type = pStream->GetDict()->GetInteger(FX_BSTRC("FunctionType"));
   } else if (CPDF_Dictionary* pDict = pFuncObj->AsDictionary()) {
     type = pDict->GetInteger(FX_BSTRC("FunctionType"));
   } else {
@@ -849,20 +847,17 @@ CPDF_Function::~CPDF_Function() {
   FX_Free(m_pRanges);
 }
 FX_BOOL CPDF_Function::Init(CPDF_Object* pObj) {
-  CPDF_Dictionary* pDict;
-  if (pObj->GetType() == PDFOBJ_STREAM) {
-    pDict = ((CPDF_Stream*)pObj)->GetDict();
-  } else {
-    pDict = pObj->AsDictionary();
-  }
+  CPDF_Stream* pStream = pObj->AsStream();
+  CPDF_Dictionary* pDict = pStream ? pStream->GetDict() : pObj->AsDictionary();
+
   CPDF_Array* pDomains = pDict->GetArray(FX_BSTRC("Domain"));
-  if (pDomains == NULL) {
+  if (!pDomains)
     return FALSE;
-  }
+
   m_nInputs = pDomains->GetCount() / 2;
-  if (m_nInputs == 0) {
+  if (m_nInputs == 0)
     return FALSE;
-  }
+
   m_pDomains = FX_Alloc2D(FX_FLOAT, m_nInputs, 2);
   for (int i = 0; i < m_nInputs * 2; i++) {
     m_pDomains[i] = pDomains->GetFloat(i);
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp
index 9cdf00e717..a24da0adc1 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp
@@ -45,15 +45,14 @@ void CPDF_Image::Release() {
   }
 }
 CPDF_Image* CPDF_Image::Clone() {
-  if (m_pStream->GetObjNum()) {
+  if (m_pStream->GetObjNum())
     return m_pDocument->GetPageData()->GetImage(m_pStream);
-  }
+
   CPDF_Image* pImage = new CPDF_Image(m_pDocument);
-  pImage->LoadImageF((CPDF_Stream*)((CPDF_Object*)m_pStream)->Clone(),
-                     m_bInline);
-  if (m_bInline) {
+  pImage->LoadImageF(ToStream(m_pStream->Clone()), m_bInline);
+  if (m_bInline)
     pImage->SetInlineDict(ToDictionary(m_pInlineDict->Clone(TRUE)));
-  }
+
   return pImage;
 }
 CPDF_Image::CPDF_Image(CPDF_Document* pDoc) {
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
index 7aa2cf8aa3..3295b7f9e0 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp
@@ -716,12 +716,12 @@ void CPDF_StreamContentParser::Handle_ExecuteXObject() {
       return;
     }
   }
-  CPDF_Stream* pXObject =
-      (CPDF_Stream*)FindResourceObj(FX_BSTRC("XObject"), name);
-  if (pXObject == NULL || pXObject->GetType() != PDFOBJ_STREAM) {
+  CPDF_Stream* pXObject = ToStream(FindResourceObj(FX_BSTRC("XObject"), name));
+  if (!pXObject) {
     m_bResourceMissing = TRUE;
     return;
   }
+
   CFX_ByteStringC type =
       pXObject->GetDict()
           ? pXObject->GetDict()->GetConstString(FX_BSTRC("Subtype"))
@@ -1151,7 +1151,7 @@ void CPDF_StreamContentParser::Handle_ShadeFill() {
     bbox = m_BBox;
   }
   if (pShading->m_ShadingType >= 4) {
-    bbox.Intersect(_GetShadingBBox((CPDF_Stream*)pShading->m_pShadingObj,
+    bbox.Intersect(_GetShadingBBox(ToStream(pShading->m_pShadingObj),
                                    pShading->m_ShadingType, &pObj->m_Matrix,
                                    pShading->m_pFunctions, pShading->m_nFuncs,
                                    pShading->m_pCS));
@@ -1262,8 +1262,7 @@ CPDF_Pattern* CPDF_StreamContentParser::FindPattern(const CFX_ByteString& name,
                                                     FX_BOOL bShading) {
   CPDF_Object* pPattern = FindResourceObj(
       bShading ? FX_BSTRC("Shading") : FX_BSTRC("Pattern"), name);
-  if (pPattern == NULL ||
-      (!pPattern->IsDictionary() && pPattern->GetType() != PDFOBJ_STREAM)) {
+  if (!pPattern || (!pPattern->IsDictionary() && !pPattern->IsStream())) {
     m_bResourceMissing = TRUE;
     return NULL;
   }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
index c27ede44cb..b86d00851c 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
@@ -960,10 +960,10 @@ void CPDF_ContentParser::Start(CPDF_Page* pPage, CPDF_ParseOptions* pOptions) {
     m_Status = Done;
     return;
   }
-  if (pContent->GetType() == PDFOBJ_STREAM) {
+  if (CPDF_Stream* pStream = pContent->AsStream()) {
     m_nStreams = 0;
     m_pSingleStream = new CPDF_StreamAcc;
-    m_pSingleStream->LoadAllData((CPDF_Stream*)pContent, FALSE);
+    m_pSingleStream->LoadAllData(pStream, FALSE);
   } else if (CPDF_Array* pArray = pContent->AsArray()) {
     m_nStreams = pArray->GetCount();
     if (m_nStreams == 0) {
@@ -1078,9 +1078,8 @@ void CPDF_ContentParser::Continue(IFX_Pause* pPause) {
         CPDF_Array* pContent =
             m_pObjects->m_pFormDict->GetArray(FX_BSTRC("Contents"));
         m_pStreamArray[m_CurrentOffset] = new CPDF_StreamAcc;
-        CPDF_Stream* pStreamObj =
-            (CPDF_Stream*)(pContent ? pContent->GetElementValue(m_CurrentOffset)
-                                    : NULL);
+        CPDF_Stream* pStreamObj = ToStream(
+            pContent ? pContent->GetElementValue(m_CurrentOffset) : nullptr);
         m_pStreamArray[m_CurrentOffset]->LoadAllData(pStreamObj, FALSE);
         m_CurrentOffset++;
       }
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
index a73bdc9e8e..7b04d8cd33 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp
@@ -38,20 +38,21 @@ CPDF_TilingPattern::~CPDF_TilingPattern() {
   m_pForm = NULL;
 }
 FX_BOOL CPDF_TilingPattern::Load() {
-  if (m_pForm != NULL) {
+  if (m_pForm)
     return TRUE;
-  }
+
   CPDF_Dictionary* pDict = m_pPatternObj->GetDict();
-  if (pDict == NULL) {
+  if (!pDict)
     return FALSE;
-  }
+
   m_bColored = pDict->GetInteger(FX_BSTRC("PaintType")) == 1;
   m_XStep = (FX_FLOAT)FXSYS_fabs(pDict->GetNumber(FX_BSTRC("XStep")));
   m_YStep = (FX_FLOAT)FXSYS_fabs(pDict->GetNumber(FX_BSTRC("YStep")));
-  if (m_pPatternObj->GetType() != PDFOBJ_STREAM) {
+
+  CPDF_Stream* pStream = m_pPatternObj->AsStream();
+  if (!pStream)
     return FALSE;
-  }
-  CPDF_Stream* pStream = (CPDF_Stream*)m_pPatternObj;
+
   m_pForm = new CPDF_Form(m_pDocument, NULL, pStream);
   m_pForm->ParseContent(NULL, &m_ParentMatrix, NULL, NULL);
   m_BBox = pDict->GetRect(FX_BSTRC("BBox"));
@@ -253,14 +254,13 @@ CFX_FloatRect _GetShadingBBox(CPDF_Stream* pStream,
                               CPDF_Function** pFuncs,
                               int nFuncs,
                               CPDF_ColorSpace* pCS) {
-  if (pStream == NULL || pStream->GetType() != PDFOBJ_STREAM ||
-      pFuncs == NULL || pCS == NULL) {
+  if (!pStream || !pStream->IsStream() || !pFuncs || !pCS)
     return CFX_FloatRect(0, 0, 0, 0);
-  }
+
   CPDF_MeshStream stream;
-  if (!stream.Load(pStream, pFuncs, nFuncs, pCS)) {
+  if (!stream.Load(pStream, pFuncs, nFuncs, pCS))
     return CFX_FloatRect(0, 0, 0, 0);
-  }
+
   CFX_FloatRect rect;
   FX_BOOL bStarted = FALSE;
   FX_BOOL bGouraud = type == 4 || type == 5;
@@ -288,9 +288,8 @@ CFX_FloatRect _GetShadingBBox(CPDF_Stream* pStream,
     }
     stream.m_BitStream.SkipBits(stream.m_nComps * stream.m_nCompBits *
                                 color_count);
-    if (bGouraud) {
+    if (bGouraud)
       stream.m_BitStream.ByteAlign();
-    }
   }
   rect.Transform(pMatrix);
   return rect;