Add FPDFFormObj_GetObject() API

To be used together with the existing FPDFFormObj_CountObjects()
function.

Change-Id: I8ed69624e967708c8db7e8f135e28fbe6a52752f
Reviewed-on: https://pdfium-review.googlesource.com/37890
Reviewed-by: Nicolás Peña Moreno <npm@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>

1 files changed, 29 insertions, 12 deletions

diff --git a/fpdfsdk/fpdf_editpage.cpp b/fpdfsdk/fpdf_editpage.cpp
index ded55b9bef..f1dbf70192 100644
--- a/fpdfsdk/fpdf_editpage.cpp
+++ b/fpdfsdk/fpdf_editpage.cpp
@@ -140,6 +140,23 @@ unsigned int GetUnsignedAlpha(float alpha) {
   return static_cast<unsigned int>(alpha * 255.f + 0.5f);
 }
 
+const CPDF_PageObjectList* CPDFPageObjListFromFPDFFormObject(
+    FPDF_PAGEOBJECT page_object) {
+  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
+  if (!pPageObj)
+    return nullptr;
+
+  CPDF_FormObject* pFormObject = pPageObj->AsForm();
+  if (!pFormObject)
+    return nullptr;
+
+  const CPDF_Form* pForm = pFormObject->form();
+  if (!pForm)
+    return nullptr;
+
+  return pForm->GetPageObjectList();
+}
+
 }  // namespace
 
 FPDF_EXPORT FPDF_DOCUMENT FPDF_CALLCONV FPDF_CreateNewDocument() {
@@ -812,21 +829,21 @@ FPDFPageObj_SetLineCap(FPDF_PAGEOBJECT page_object, int line_cap) {
 
 FPDF_EXPORT int FPDF_CALLCONV
 FPDFFormObj_CountObjects(FPDF_PAGEOBJECT page_object) {
-  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
-  if (!pPageObj)
-    return -1;
-
-  CPDF_FormObject* pFormObject = pPageObj->AsForm();
-  if (!pFormObject)
+  const CPDF_PageObjectList* pObjectList =
+      CPDFPageObjListFromFPDFFormObject(page_object);
+  if (!pObjectList)
     return -1;
 
-  const CPDF_Form* pForm = pFormObject->form();
-  if (!pForm)
-    return -1;
+  return pObjectList->size();
+}
 
-  const CPDF_PageObjectList* pObjectList = pForm->GetPageObjectList();
+FPDF_EXPORT FPDF_PAGEOBJECT FPDF_CALLCONV
+FPDFFormObj_GetObject(FPDF_PAGEOBJECT form_object, unsigned long index) {
+  const CPDF_PageObjectList* pObjectList =
+      CPDFPageObjListFromFPDFFormObject(form_object);
   if (!pObjectList)
-    return -1;
+    return nullptr;
 
-  return pObjectList->size();
+  return FPDFPageObjectFromCPDFPageObject(
+      pObjectList->GetPageObjectByIndex(index));
 }