Add type cast definitions for CPDF_Stream.

core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp

Index: core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
diff --git a/core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp b/core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
index b64002c13ebdbf923ce8d230a96d7174e2b5347a..f86d1d856fd613311d331887d6032bf2c731dd7a 100644
--- a/core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
+++ b/core/src/fpdfapi/fpdf_render/fpdf_render_pattern.cpp
@@ -416,13 +416,13 @@ static void _DrawFreeGouraudShading(CFX_DIBitmap* pBitmap,
                                     CPDF_ColorSpace* pCS,
                                     int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
-  if (pShadingStream->GetType() != PDFOBJ_STREAM) {
+  if (!pShadingStream->IsStream())

[Tom Sepez, 2015/10/22 17:16:45]

Can a stream be not IsStream() ?  Either this should take an object argument and
we call ToStream here, or the callers should call ToStream() and we do a null
check here.

[dsinclair, 2015/10/22 17:42:56]

Done. Probably bad casts in the past.

     return;
-  }
+
   CPDF_MeshStream stream;
-  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS)) {
+  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS))
     return;
-  }
+
   CPDF_MeshVertex triangle[3];
   FXSYS_memset(triangle, 0, sizeof(triangle));
 
@@ -452,17 +452,17 @@ static void _DrawLatticeGouraudShading(CFX_DIBitmap* pBitmap,
                                        CPDF_ColorSpace* pCS,
                                        int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
-  if (pShadingStream->GetType() != PDFOBJ_STREAM) {
+  if (!pShadingStream->IsStream())

[Tom Sepez, 2015/10/22 17:16:45]

ditto

[dsinclair, 2015/10/22 17:42:56]

Done.

     return;
-  }
+
   int row_verts = pShadingStream->GetDict()->GetInteger("VerticesPerRow");
-  if (row_verts < 2) {
+  if (row_verts < 2)
     return;
-  }
+
   CPDF_MeshStream stream;
-  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS)) {
+  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS))
     return;
-  }
+
   CPDF_MeshVertex* vertex = FX_Alloc2D(CPDF_MeshVertex, row_verts, 2);
   if (!stream.GetVertexRow(vertex, row_verts, pObject2Bitmap)) {
     FX_Free(vertex);
@@ -758,19 +758,16 @@ static void _DrawCoonPatchMeshes(FX_BOOL bTensor,
                                  int fill_mode,
                                  int alpha) {
   ASSERT(pBitmap->GetFormat() == FXDIB_Argb);
-  if (pShadingStream->GetType() != PDFOBJ_STREAM) {
+  if (!pShadingStream->IsStream())

[Tom Sepez, 2015/10/22 17:16:45]

ditto ditto

[dsinclair, 2015/10/22 17:42:56]

Done.

     return;
-  }
+
   CFX_FxgeDevice device;
   device.Attach(pBitmap);
   CPDF_MeshStream stream;
-  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS)) {
+  if (!stream.Load(pShadingStream, pFuncs, nFuncs, pCS))
     return;
-  }
-
-  if (!_CheckCoonTensorPara(stream)) {
+  if (!_CheckCoonTensorPara(stream))
     return;
-  }
 
   CPDF_PatchDrawer patch;
   patch.alpha = alpha;
@@ -891,19 +888,19 @@ void CPDF_RenderStatus::DrawShading(CPDF_ShadingPattern* pPattern,
       break;
     case 4: {
       _DrawFreeGouraudShading(pBitmap, &FinalMatrix,
-                              (CPDF_Stream*)pPattern->m_pShadingObj, pFuncs,
-                              nFuncs, pColorSpace, alpha);
+                              ToStream(pPattern->m_pShadingObj), pFuncs, nFuncs,
+                              pColorSpace, alpha);
     } break;
     case 5: {
       _DrawLatticeGouraudShading(pBitmap, &FinalMatrix,
-                                 (CPDF_Stream*)pPattern->m_pShadingObj, pFuncs,
+                                 ToStream(pPattern->m_pShadingObj), pFuncs,
                                  nFuncs, pColorSpace, alpha);
     } break;
     case 6:
     case 7: {
       _DrawCoonPatchMeshes(pPattern->m_ShadingType - 6, pBitmap, &FinalMatrix,
-                           (CPDF_Stream*)pPattern->m_pShadingObj, pFuncs,
-                           nFuncs, pColorSpace, fill_mode, alpha);
+                           ToStream(pPattern->m_pShadingObj), pFuncs, nFuncs,
+                           pColorSpace, fill_mode, alpha);
     } break;
   }
   if (bAlphaMode) {