Add FPDFAnnot_GetFormFieldFlags() and associated embedder tests.

Given an interactive form annotation, this method returns its annotation
flags. The flags returned are dependent upon the "Ff" field, and are
specific to interactive form annotations, such as
FPDF_FORMFLAG_MULTILINE, FPDF_FORMFLAG_COMBO, FPDF_FORMFLAG_EDIT, and
others.

To test this method more thoroughly, text_form_multiple.pdf has been
added, which is similar to text_form.pdf, but includes a read-only text
field.

BUG=chromium:59266

Change-Id: Ie66046de273f69a1be6f04a433351ebaa271f60c
Reviewed-on: https://pdfium-review.googlesource.com/7851
Commit-Queue: Diana Gage <drgage@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

3 files changed, 88 insertions, 0 deletions

diff --git a/fpdfsdk/fpdfannot.cpp b/fpdfsdk/fpdfannot.cpp
index 1c4345ab52..f3a9ea1b72 100644
--- a/fpdfsdk/fpdfannot.cpp
+++ b/fpdfsdk/fpdfannot.cpp
@@ -18,6 +18,8 @@
 #include "core/fpdfapi/parser/cpdf_number.h"
 #include "core/fpdfapi/parser/cpdf_string.h"
 #include "core/fpdfdoc/cpdf_annot.h"
+#include "core/fpdfdoc/cpdf_formfield.h"
+#include "core/fpdfdoc/cpdf_interform.h"
 #include "core/fpdfdoc/cpvt_color.h"
 #include "core/fpdfdoc/cpvt_generateap.h"
 #include "fpdfsdk/fsdk_define.h"
@@ -786,3 +788,19 @@ DLLEXPORT FPDF_BOOL STDCALL FPDFAnnot_SetFlags(FPDF_ANNOTATION annot,
   pAnnotDict->SetNewFor<CPDF_Number>("F", flags);
   return true;
 }
+
+DLLEXPORT int STDCALL FPDFAnnot_GetFormFieldFlags(FPDF_PAGE page,
+                                                  FPDF_ANNOTATION annot) {
+  CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
+  if (!pPage || !annot)
+    return FPDF_FORMFLAG_NONE;
+
+  CPDF_Dictionary* pAnnotDict =
+      CPDFAnnotContextFromFPDFAnnotation(annot)->GetAnnotDict();
+  if (!pAnnotDict)
+    return FPDF_FORMFLAG_NONE;
+
+  CPDF_InterForm interform(pPage->m_pDocument.Get());
+  CPDF_FormField* pFormField = interform.GetFieldByDict(pAnnotDict);
+  return pFormField ? pFormField->GetFieldFlags() : FPDF_FORMFLAG_NONE;
+}
diff --git a/fpdfsdk/fpdfannot_embeddertest.cpp b/fpdfsdk/fpdfannot_embeddertest.cpp
index c042b764a2..b50f73f3ab 100644
--- a/fpdfsdk/fpdfannot_embeddertest.cpp
+++ b/fpdfsdk/fpdfannot_embeddertest.cpp
@@ -887,3 +887,72 @@ TEST_F(FPDFAnnotEmbeddertest, GetSetStringValue) {
   FPDFPage_CloseAnnot(new_annot);
   CloseSaved();
 }
+
+TEST_F(FPDFAnnotEmbeddertest, GetFormFieldFlagsTextField) {
+  // Open file with form text fields.
+  ASSERT_TRUE(OpenDocument("text_form_multiple.pdf"));
+  FPDF_PAGE page = FPDF_LoadPage(document(), 0);
+  ASSERT_TRUE(page);
+
+  // Retrieve the first annotation: user-editable text field.
+  FPDF_ANNOTATION annot = FPDFPage_GetAnnot(page, 0);
+  ASSERT_TRUE(annot);
+
+  // Check that the flag values are as expected.
+  int flags = FPDFAnnot_GetFormFieldFlags(page, annot);
+  EXPECT_FALSE(flags & FPDF_FORMFLAG_READONLY);
+  FPDFPage_CloseAnnot(annot);
+
+  // Retrieve the second annotation: read-only text field.
+  annot = FPDFPage_GetAnnot(page, 1);
+  ASSERT_TRUE(annot);
+
+  // Check that the flag values are as expected.
+  flags = FPDFAnnot_GetFormFieldFlags(page, annot);
+  EXPECT_TRUE(flags & FPDF_FORMFLAG_READONLY);
+  FPDFPage_CloseAnnot(annot);
+
+  UnloadPage(page);
+}
+
+TEST_F(FPDFAnnotEmbeddertest, GetFormFieldFlagsComboBox) {
+  // Open file with form text fields.
+  ASSERT_TRUE(OpenDocument("combobox_form.pdf"));
+  FPDF_PAGE page = FPDF_LoadPage(document(), 0);
+  ASSERT_TRUE(page);
+
+  // Retrieve the first annotation: user-editable combobox.
+  FPDF_ANNOTATION annot = FPDFPage_GetAnnot(page, 0);
+  ASSERT_TRUE(annot);
+
+  // Check that the flag values are as expected.
+  int flags = FPDFAnnot_GetFormFieldFlags(page, annot);
+  EXPECT_FALSE(flags & FPDF_FORMFLAG_READONLY);
+  EXPECT_TRUE(flags & FPDF_FORMFLAG_CHOICE_COMBO);
+  EXPECT_TRUE(flags & FPDF_FORMFLAG_CHOICE_EDIT);
+  FPDFPage_CloseAnnot(annot);
+
+  // Retrieve the second annotation: regular combobox.
+  annot = FPDFPage_GetAnnot(page, 1);
+  ASSERT_TRUE(annot);
+
+  // Check that the flag values are as expected.
+  flags = FPDFAnnot_GetFormFieldFlags(page, annot);
+  EXPECT_FALSE(flags & FPDF_FORMFLAG_READONLY);
+  EXPECT_TRUE(flags & FPDF_FORMFLAG_CHOICE_COMBO);
+  EXPECT_FALSE(flags & FPDF_FORMFLAG_CHOICE_EDIT);
+  FPDFPage_CloseAnnot(annot);
+
+  // Retrieve the third annotation: read-only combobox.
+  annot = FPDFPage_GetAnnot(page, 2);
+  ASSERT_TRUE(annot);
+
+  // Check that the flag values are as expected.
+  flags = FPDFAnnot_GetFormFieldFlags(page, annot);
+  EXPECT_TRUE(flags & FPDF_FORMFLAG_READONLY);
+  EXPECT_TRUE(flags & FPDF_FORMFLAG_CHOICE_COMBO);
+  EXPECT_FALSE(flags & FPDF_FORMFLAG_CHOICE_EDIT);
+  FPDFPage_CloseAnnot(annot);
+
+  UnloadPage(page);
+}
diff --git a/fpdfsdk/fpdfview_c_api_test.c b/fpdfsdk/fpdfview_c_api_test.c
index 6753e66c52..1405b40ce8 100644
--- a/fpdfsdk/fpdfview_c_api_test.c
+++ b/fpdfsdk/fpdfview_c_api_test.c
@@ -61,6 +61,7 @@ int CheckPDFiumCApi() {
     CHK(FPDFAnnot_GetStringValue);
     CHK(FPDFAnnot_GetFlags);
     CHK(FPDFAnnot_SetFlags);
+    CHK(FPDFAnnot_GetFormFieldFlags);
 
     // fpdf_attachment.h
     CHK(FPDFDoc_GetAttachmentCount);