Check CPDFFooObjectFromFPDFPageObject() result.

Instead of checking the FPDF_OBJECT itself. Remove redundant checks and
fix nits.

Change-Id: Id566847d39d16331c08f0b5f3b46431716717b5c
Reviewed-on: https://pdfium-review.googlesource.com/c/44535
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

4 files changed, 85 insertions, 105 deletions

diff --git a/fpdfsdk/fpdf_editimg.cpp b/fpdfsdk/fpdf_editimg.cpp
index be7e571afe..af4d125db0 100644
--- a/fpdfsdk/fpdf_editimg.cpp
+++ b/fpdfsdk/fpdf_editimg.cpp
@@ -51,17 +51,22 @@ RetainPtr<IFX_SeekableReadStream> MakeSeekableReadStream(
   return pdfium::MakeRetain<CPDFSDK_CustomAccess>(pFileAccess);
 }
 
+CPDF_ImageObject* CPDFImageObjectFromFPDFPageObject(
+    FPDF_PAGEOBJECT image_object) {
+  CPDF_PageObject* pPageObject = CPDFPageObjectFromFPDFPageObject(image_object);
+  return pPageObject ? pPageObject->AsImage() : nullptr;
+}
+
 bool LoadJpegHelper(FPDF_PAGE* pages,
                     int nCount,
                     FPDF_PAGEOBJECT image_object,
                     FPDF_FILEACCESS* fileAccess,
                     bool inlineJpeg) {
-  if (!image_object || !fileAccess)
+  CPDF_ImageObject* pImgObj = CPDFImageObjectFromFPDFPageObject(image_object);
+  if (!pImgObj)
     return false;
 
-  CPDF_ImageObject* pImgObj =
-      CPDFPageObjectFromFPDFPageObject(image_object)->AsImage();
-  if (!pImgObj)
+  if (!fileAccess)
     return false;
 
   if (pages) {
@@ -120,11 +125,7 @@ FPDFImageObj_SetMatrix(FPDF_PAGEOBJECT image_object,
                        double d,
                        double e,
                        double f) {
-  if (!image_object)
-    return false;
-
-  CPDF_ImageObject* pImgObj =
-      CPDFPageObjectFromFPDFPageObject(image_object)->AsImage();
+  CPDF_ImageObject* pImgObj = CPDFImageObjectFromFPDFPageObject(image_object);
   if (!pImgObj)
     return false;
 
@@ -141,14 +142,16 @@ FPDFImageObj_SetBitmap(FPDF_PAGE* pages,
                        int nCount,
                        FPDF_PAGEOBJECT image_object,
                        FPDF_BITMAP bitmap) {
-  if (!image_object || !bitmap || !pages)
+  if (!pages)
     return false;
 
-  CPDF_ImageObject* pImgObj =
-      CPDFPageObjectFromFPDFPageObject(image_object)->AsImage();
+  CPDF_ImageObject* pImgObj = CPDFImageObjectFromFPDFPageObject(image_object);
   if (!pImgObj)
     return false;
 
+  if (!bitmap)
+    return false;
+
   for (int index = 0; index < nCount; index++) {
     CPDF_Page* pPage = CPDFPageFromFPDFPage(pages[index]);
     if (pPage)
@@ -163,11 +166,11 @@ FPDFImageObj_SetBitmap(FPDF_PAGE* pages,
 
 FPDF_EXPORT FPDF_BITMAP FPDF_CALLCONV
 FPDFImageObj_GetBitmap(FPDF_PAGEOBJECT image_object) {
-  CPDF_PageObject* pObj = CPDFPageObjectFromFPDFPageObject(image_object);
-  if (!pObj || !pObj->IsImage())
+  CPDF_ImageObject* pImgObj = CPDFImageObjectFromFPDFPageObject(image_object);
+  if (!pImgObj)
     return nullptr;
 
-  RetainPtr<CPDF_Image> pImg = pObj->AsImage()->GetImage();
+  RetainPtr<CPDF_Image> pImg = pImgObj->GetImage();
   if (!pImg)
     return nullptr;
 
@@ -192,11 +195,11 @@ FPDF_EXPORT unsigned long FPDF_CALLCONV
 FPDFImageObj_GetImageDataDecoded(FPDF_PAGEOBJECT image_object,
                                  void* buffer,
                                  unsigned long buflen) {
-  CPDF_PageObject* pObj = CPDFPageObjectFromFPDFPageObject(image_object);
-  if (!pObj || !pObj->IsImage())
+  CPDF_ImageObject* pImgObj = CPDFImageObjectFromFPDFPageObject(image_object);
+  if (!pImgObj)
     return 0;
 
-  RetainPtr<CPDF_Image> pImg = pObj->AsImage()->GetImage();
+  RetainPtr<CPDF_Image> pImg = pImgObj->GetImage();
   if (!pImg)
     return 0;
 
@@ -211,11 +214,11 @@ FPDF_EXPORT unsigned long FPDF_CALLCONV
 FPDFImageObj_GetImageDataRaw(FPDF_PAGEOBJECT image_object,
                              void* buffer,
                              unsigned long buflen) {
-  CPDF_PageObject* pObj = CPDFPageObjectFromFPDFPageObject(image_object);
-  if (!pObj || !pObj->IsImage())
+  CPDF_ImageObject* pImgObj = CPDFImageObjectFromFPDFPageObject(image_object);
+  if (!pImgObj)
     return 0;
 
-  RetainPtr<CPDF_Image> pImg = pObj->AsImage()->GetImage();
+  RetainPtr<CPDF_Image> pImg = pImgObj->GetImage();
   if (!pImg)
     return 0;
 
@@ -236,11 +239,11 @@ FPDFImageObj_GetImageDataRaw(FPDF_PAGEOBJECT image_object,
 
 FPDF_EXPORT int FPDF_CALLCONV
 FPDFImageObj_GetImageFilterCount(FPDF_PAGEOBJECT image_object) {
-  CPDF_PageObject* pObj = CPDFPageObjectFromFPDFPageObject(image_object);
-  if (!pObj || !pObj->IsImage())
+  CPDF_ImageObject* pImgObj = CPDFImageObjectFromFPDFPageObject(image_object);
+  if (!pImgObj)
     return 0;
 
-  RetainPtr<CPDF_Image> pImg = pObj->AsImage()->GetImage();
+  RetainPtr<CPDF_Image> pImg = pImgObj->GetImage();
   if (!pImg)
     return 0;
 
@@ -284,23 +287,23 @@ FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFImageObj_GetImageMetadata(FPDF_PAGEOBJECT image_object,
                               FPDF_PAGE page,
                               FPDF_IMAGEOBJ_METADATA* metadata) {
-  CPDF_PageObject* pObj = CPDFPageObjectFromFPDFPageObject(image_object);
-  if (!pObj || !pObj->IsImage() || !metadata)
+  CPDF_ImageObject* pImgObj = CPDFImageObjectFromFPDFPageObject(image_object);
+  if (!pImgObj || !metadata)
     return false;
 
-  RetainPtr<CPDF_Image> pImg = pObj->AsImage()->GetImage();
+  RetainPtr<CPDF_Image> pImg = pImgObj->GetImage();
   if (!pImg)
     return false;
 
-  metadata->marked_content_id = pObj->m_ContentMarks.GetMarkedContentID();
+  metadata->marked_content_id = pImgObj->m_ContentMarks.GetMarkedContentID();
 
   const int nPixelWidth = pImg->GetPixelWidth();
   const int nPixelHeight = pImg->GetPixelHeight();
   metadata->width = nPixelWidth;
   metadata->height = nPixelHeight;
 
-  const float nWidth = pObj->GetRect().Width();
-  const float nHeight = pObj->GetRect().Height();
+  const float nWidth = pImgObj->GetRect().Width();
+  const float nHeight = pImgObj->GetRect().Height();
   constexpr int nPointsPerInch = 72;
   if (nWidth != 0 && nHeight != 0) {
     metadata->horizontal_dpi = nPixelWidth / nWidth * nPointsPerInch;
diff --git a/fpdfsdk/fpdf_editpage.cpp b/fpdfsdk/fpdf_editpage.cpp
index 585e7e1740..d0ff962252 100644
--- a/fpdfsdk/fpdf_editpage.cpp
+++ b/fpdfsdk/fpdf_editpage.cpp
@@ -137,13 +137,14 @@ unsigned int GetUnsignedAlpha(float alpha) {
   return static_cast<unsigned int>(alpha * 255.f + 0.5f);
 }
 
-const CPDF_PageObjectList* CPDFPageObjListFromFPDFFormObject(
-    FPDF_PAGEOBJECT page_object) {
+CPDF_FormObject* CPDFFormObjectFromFPDFPageObject(FPDF_PAGEOBJECT page_object) {
   auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
-  if (!pPageObj)
-    return nullptr;
+  return pPageObj ? pPageObj->AsForm() : nullptr;
+}
 
-  CPDF_FormObject* pFormObject = pPageObj->AsForm();
+const CPDF_PageObjectList* CPDFPageObjListFromFPDFFormObject(
+    FPDF_PAGEOBJECT page_object) {
+  CPDF_FormObject* pFormObject = CPDFFormObjectFromFPDFPageObject(page_object);
   if (!pFormObject)
     return nullptr;
 
@@ -250,8 +251,8 @@ FPDF_EXPORT void FPDF_CALLCONV FPDFPage_InsertObject(FPDF_PAGE page,
   CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
   if (!IsPageObject(pPage))
     return;
-  pPageObj->SetDirty(true);
 
+  pPageObj->SetDirty(true);
   pPage->AppendPageObject(std::move(pPageObjHolder));
   CalcBoundingBox(pPageObj);
 }
@@ -297,24 +298,24 @@ FPDF_EXPORT void FPDF_CALLCONV FPDFPageObj_Destroy(FPDF_PAGEOBJECT page_obj) {
 
 FPDF_EXPORT int FPDF_CALLCONV
 FPDFPageObj_CountMarks(FPDF_PAGEOBJECT page_object) {
-  if (!page_object)
+  CPDF_PageObject* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
+  if (!pPageObj)
     return -1;
 
-  const auto& mark =
-      CPDFPageObjectFromFPDFPageObject(page_object)->m_ContentMarks;
-  return mark.CountItems();
+  return pPageObj->m_ContentMarks.CountItems();
 }
 
 FPDF_EXPORT FPDF_PAGEOBJECTMARK FPDF_CALLCONV
 FPDFPageObj_GetMark(FPDF_PAGEOBJECT page_object, unsigned long index) {
-  if (!page_object)
+  CPDF_PageObject* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
+  if (!pPageObj)
     return nullptr;
 
-  auto* mark = &CPDFPageObjectFromFPDFPageObject(page_object)->m_ContentMarks;
-  if (index >= mark->CountItems())
+  auto& mark = pPageObj->m_ContentMarks;
+  if (index >= mark.CountItems())
     return nullptr;
 
-  return FPDFPageObjectMarkFromCPDFContentMarkItem(mark->GetItem(index));
+  return FPDFPageObjectMarkFromCPDFContentMarkItem(mark.GetItem(index));
 }
 
 FPDF_EXPORT FPDF_PAGEOBJECTMARK FPDF_CALLCONV
@@ -323,13 +324,11 @@ FPDFPageObj_AddMark(FPDF_PAGEOBJECT page_object, FPDF_BYTESTRING name) {
   if (!pPageObj)
     return nullptr;
 
-  auto* mark = &pPageObj->m_ContentMarks;
-  mark->AddMark(name);
-  unsigned long index = mark->CountItems() - 1;
-
+  auto& mark = pPageObj->m_ContentMarks;
+  mark.AddMark(name);
+  unsigned long index = mark.CountItems() - 1;
   pPageObj->SetDirty(true);
-
-  return FPDFPageObjectMarkFromCPDFContentMarkItem(mark->GetItem(index));
+  return FPDFPageObjectMarkFromCPDFContentMarkItem(mark.GetItem(index));
 }
 
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
@@ -483,10 +482,10 @@ FPDFPageObjMark_GetParamBlobValue(FPDF_PAGEOBJECTMARK mark,
 
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFPageObj_HasTransparency(FPDF_PAGEOBJECT pageObject) {
-  if (!pageObject)
+  CPDF_PageObject* pPageObj = CPDFPageObjectFromFPDFPageObject(pageObject);
+  if (!pPageObj)
     return false;
 
-  CPDF_PageObject* pPageObj = CPDFPageObjectFromFPDFPageObject(pageObject);
   int blend_type = pPageObj->m_GeneralState.GetBlendType();
   if (blend_type != FXDIB_BLEND_NORMAL)
     return true;
@@ -598,11 +597,8 @@ FPDFPageObjMark_RemoveParam(FPDF_PAGEOBJECT page_object,
 }
 
 FPDF_EXPORT int FPDF_CALLCONV FPDFPageObj_GetType(FPDF_PAGEOBJECT pageObject) {
-  if (!pageObject)
-    return FPDF_PAGEOBJ_UNKNOWN;
-
   CPDF_PageObject* pPageObj = CPDFPageObjectFromFPDFPageObject(pageObject);
-  return pPageObj->GetType();
+  return pPageObj ? pPageObj->GetType() : FPDF_PAGEOBJ_UNKNOWN;
 }
 
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFPage_GenerateContent(FPDF_PAGE page) {
@@ -692,11 +688,11 @@ FPDF_BOOL FPDFPageObj_SetFillColor(FPDF_PAGEOBJECT page_object,
                                    unsigned int G,
                                    unsigned int B,
                                    unsigned int A) {
-  if (!page_object || R > 255 || G > 255 || B > 255 || A > 255)
+  CPDF_PageObject* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
+  if (!pPageObj || R > 255 || G > 255 || B > 255 || A > 255)
     return false;
 
   std::vector<float> rgb = {R / 255.f, G / 255.f, B / 255.f};
-  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
   pPageObj->m_GeneralState.SetFillAlpha(A / 255.f);
   pPageObj->m_ColorState.SetFillColor(
       CPDF_ColorSpace::GetStockCS(PDFCS_DEVICERGB), rgb);
@@ -728,10 +724,10 @@ FPDFPageObj_GetBounds(FPDF_PAGEOBJECT pageObject,
                       float* bottom,
                       float* right,
                       float* top) {
-  if (!pageObject)
+  CPDF_PageObject* pPageObj = CPDFPageObjectFromFPDFPageObject(pageObject);
+  if (!pPageObj)
     return false;
 
-  CPDF_PageObject* pPageObj = CPDFPageObjectFromFPDFPageObject(pageObject);
   const CFX_FloatRect& bbox = pPageObj->GetRect();
   *left = bbox.left;
   *bottom = bbox.bottom;
@@ -799,34 +795,38 @@ FPDFPageObj_GetStrokeWidth(FPDF_PAGEOBJECT page_object, float* width) {
 
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFPageObj_SetLineJoin(FPDF_PAGEOBJECT page_object, int line_join) {
-  if (!page_object)
+  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
+  if (!pPageObj)
     return false;
-  if (line_join <
-          static_cast<int>(CFX_GraphStateData::LineJoin::LineJoinMiter) ||
-      line_join >
-          static_cast<int>(CFX_GraphStateData::LineJoin::LineJoinBevel)) {
+
+  constexpr int kLineJoinMiter =
+      static_cast<int>(CFX_GraphStateData::LineJoin::LineJoinMiter);
+  constexpr int kLineJoinBevel =
+      static_cast<int>(CFX_GraphStateData::LineJoin::LineJoinBevel);
+  if (line_join < kLineJoinMiter || line_join > kLineJoinBevel)
     return false;
-  }
-  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
-  CFX_GraphStateData::LineJoin lineJoin =
-      static_cast<CFX_GraphStateData::LineJoin>(line_join);
-  pPageObj->m_GraphState.SetLineJoin(lineJoin);
+
+  pPageObj->m_GraphState.SetLineJoin(
+      static_cast<CFX_GraphStateData::LineJoin>(line_join));
   pPageObj->SetDirty(true);
   return true;
 }
 
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFPageObj_SetLineCap(FPDF_PAGEOBJECT page_object, int line_cap) {
-  if (!page_object)
+  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
+  if (!pPageObj)
     return false;
-  if (line_cap < static_cast<int>(CFX_GraphStateData::LineCap::LineCapButt) ||
-      line_cap > static_cast<int>(CFX_GraphStateData::LineCap::LineCapSquare)) {
+
+  constexpr int kLineCapButt =
+      static_cast<int>(CFX_GraphStateData::LineCap::LineCapButt);
+  constexpr int kLineCapSquare =
+      static_cast<int>(CFX_GraphStateData::LineCap::LineCapSquare);
+  if (line_cap < kLineCapButt || line_cap > kLineCapSquare)
     return false;
-  }
-  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
-  CFX_GraphStateData::LineCap lineCap =
-      static_cast<CFX_GraphStateData::LineCap>(line_cap);
-  pPageObj->m_GraphState.SetLineCap(lineCap);
+
+  pPageObj->m_GraphState.SetLineCap(
+      static_cast<CFX_GraphStateData::LineCap>(line_cap));
   pPageObj->SetDirty(true);
   return true;
 }
@@ -835,10 +835,7 @@ FPDF_EXPORT int FPDF_CALLCONV
 FPDFFormObj_CountObjects(FPDF_PAGEOBJECT page_object) {
   const CPDF_PageObjectList* pObjectList =
       CPDFPageObjListFromFPDFFormObject(page_object);
-  if (!pObjectList)
-    return -1;
-
-  return pObjectList->size();
+  return pObjectList ? pObjectList->size() : -1;
 }
 
 FPDF_EXPORT FPDF_PAGEOBJECT FPDF_CALLCONV
@@ -860,12 +857,8 @@ FPDFFormObj_GetMatrix(FPDF_PAGEOBJECT form_object,
                       double* d,
                       double* e,
                       double* f) {
-  if (!form_object || !a || !b || !c || !d || !e || !f)
-    return false;
-
-  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(form_object);
-  CPDF_FormObject* pFormObj = pPageObj->AsForm();
-  if (!pFormObj)
+  CPDF_FormObject* pFormObj = CPDFFormObjectFromFPDFPageObject(form_object);
+  if (!pFormObj || !a || !b || !c || !d || !e || !f)
     return false;
 
   const CFX_Matrix& matrix = pFormObj->form_matrix();
@@ -875,6 +868,5 @@ FPDFFormObj_GetMatrix(FPDF_PAGEOBJECT form_object,
   *d = matrix.d;
   *e = matrix.e;
   *f = matrix.f;
-
   return true;
 }
diff --git a/fpdfsdk/fpdf_editpath.cpp b/fpdfsdk/fpdf_editpath.cpp
index a42aaa9c95..83662aa8b5 100644
--- a/fpdfsdk/fpdf_editpath.cpp
+++ b/fpdfsdk/fpdf_editpath.cpp
@@ -257,7 +257,6 @@ FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFPath_GetMatrix(FPDF_PAGEOBJECT path,
   *d = pPathObj->m_Matrix.d;
   *e = pPathObj->m_Matrix.e;
   *f = pPathObj->m_Matrix.f;
-
   return true;
 }
 
@@ -268,9 +267,6 @@ FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFPath_SetMatrix(FPDF_PAGEOBJECT path,
                                                        double d,
                                                        double e,
                                                        double f) {
-  if (!path)
-    return false;
-
   CPDF_PathObject* pPathObj = CPDFPathObjectFromFPDFPageObject(path);
   if (!pPathObj)
     return false;
@@ -282,7 +278,6 @@ FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV FPDFPath_SetMatrix(FPDF_PAGEOBJECT path,
   pPathObj->m_Matrix.e = e;
   pPathObj->m_Matrix.f = f;
   pPathObj->SetDirty(true);
-
   return true;
 }
 
@@ -312,14 +307,12 @@ FPDFPathSegment_GetPoint(FPDF_PATHSEGMENT segment, float* x, float* y) {
 
   *x = pPathPoint->m_Point.x;
   *y = pPathPoint->m_Point.y;
-
   return true;
 }
 
 FPDF_EXPORT int FPDF_CALLCONV
 FPDFPathSegment_GetType(FPDF_PATHSEGMENT segment) {
   auto* pPathPoint = FXPathPointFromFPDFPathSegment(segment);
-
   return pPathPoint ? static_cast<int>(pPathPoint->m_Type)
                     : FPDF_SEGMENT_UNKNOWN;
 }
@@ -327,6 +320,5 @@ FPDFPathSegment_GetType(FPDF_PATHSEGMENT segment) {
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFPathSegment_GetClose(FPDF_PATHSEGMENT segment) {
   auto* pPathPoint = FXPathPointFromFPDFPathSegment(segment);
-
   return pPathPoint ? pPathPoint->m_CloseFigure : false;
 }
diff --git a/fpdfsdk/fpdf_edittext.cpp b/fpdfsdk/fpdf_edittext.cpp
index 32ea6db607..1c6709f915 100644
--- a/fpdfsdk/fpdf_edittext.cpp
+++ b/fpdfsdk/fpdf_edittext.cpp
@@ -452,11 +452,7 @@ FPDFPageObj_NewTextObj(FPDF_DOCUMENT document,
 
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFText_SetText(FPDF_PAGEOBJECT text_object, FPDF_WIDESTRING text) {
-  if (!text_object)
-    return false;
-
-  CPDF_TextObject* pTextObj =
-      CPDFPageObjectFromFPDFPageObject(text_object)->AsText();
+  CPDF_TextObject* pTextObj = CPDFTextObjectFromFPDFPageObject(text_object);
   if (!pTextObj)
     return false;
 
@@ -614,9 +610,6 @@ FPDFPageObj_CreateTextObj(FPDF_DOCUMENT document,
 }
 
 FPDF_EXPORT int FPDF_CALLCONV FPDFText_GetTextRenderMode(FPDF_PAGEOBJECT text) {
-  if (!text)
-    return -1;
-
   CPDF_TextObject* pTextObj = CPDFTextObjectFromFPDFPageObject(text);
   if (!pTextObj)
     return -1;