Update form field states in PDFiumEngine

This CL updates the form field states in PDFiumEngine. This is done via
setting |PDFiumEngine::in_form_text_area_| and
|PDFiumEngine::editable_form_text_area_| as per the focused annotation.

Unit tests have been added to validate the scenario.

Bug: 989040
Change-Id: I27e163819f5ca5f88e6ce10df48f2e7c7a6e97dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2086466
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Kevin Babbitt <kbabbitt@microsoft.com>
Commit-Queue: Ankit Kumar 🌪️ <ankk@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#765557}

pdf/pdfium/pdfium_engine.cc

@@ -1114,19 +1114,9 @@ bool PDFiumEngine::OnLeftMouseDown(const pp::MouseInputEvent& event) {
     double page_y;
     DeviceToPage(page_index, point, &page_x, &page_y);
 
-    bool is_form_text_area = IsFormTextArea(area, form_type);
-    FPDF_PAGE page = pages_[page_index]->GetPage();
-    bool is_editable_form_text_area =
-        is_form_text_area &&
-        IsPointInEditableFormTextArea(page, page_x, page_y, form_type);
-
-    if (event.GetClickCount() == 1) {
-      FORM_OnLButtonDown(form(), page, event.GetModifiers(), page_x, page_y);
-    } else if (event.GetClickCount() == 2) {
-      FORM_OnLButtonDoubleClick(form(), page, event.GetModifiers(), page_x,
-                                page_y);
-    }
     if (form_type != FPDF_FORMFIELD_UNKNOWN) {
+      // FORM_OnLButton*() will trigger a callback to
+      // OnFocusedAnnotationUpdated() which will call SetInFormTextArea().
       // Destroy SelectionChangeInvalidator object before SetInFormTextArea()
       // changes plugin's focus to be in form text area. This way, regular text
       // selection can be cleared when a user clicks into a form text area
@@ -1134,11 +1124,18 @@ bool PDFiumEngine::OnLeftMouseDown(const pp::MouseInputEvent& event) {
       // ~SelectionChangeInvalidator() still goes to the Mimehandler
       // (not the Renderer).
       selection_invalidator.reset();
-
-      SetInFormTextArea(is_form_text_area);
-      editable_form_text_area_ = is_editable_form_text_area;
-      return true;  // Return now before we get into the selection code.
     }
+
+    FPDF_PAGE page = pages_[page_index]->GetPage();
+
+    if (event.GetClickCount() == 1) {
+      FORM_OnLButtonDown(form(), page, event.GetModifiers(), page_x, page_y);
+    } else if (event.GetClickCount() == 2) {
+      FORM_OnLButtonDoubleClick(form(), page, event.GetModifiers(), page_x,
+                                page_y);
+    }
+    if (form_type != FPDF_FORMFIELD_UNKNOWN)
+      return true;  // Return now before we get into the selection code.
   }
   SetInFormTextArea(false);
 
@@ -1197,7 +1194,6 @@ bool PDFiumEngine::OnRightMouseDown(const pp::MouseInputEvent& event) {
   DCHECK_GE(form_type, FPDF_FORMFIELD_UNKNOWN);
 
   bool is_form_text_area = IsFormTextArea(area, form_type);
-  bool is_editable_form_text_area = false;
 
   double page_x = -1;
   double page_y = -1;
@@ -1207,8 +1203,6 @@ bool PDFiumEngine::OnRightMouseDown(const pp::MouseInputEvent& event) {
 
     DeviceToPage(page_index, point, &page_x, &page_y);
     page = pages_[page_index]->GetPage();
-    is_editable_form_text_area =
-        IsPointInEditableFormTextArea(page, page_x, page_y, form_type);
   }
 
   // Handle the case when focus starts inside a form text area.
@@ -1231,8 +1225,6 @@ bool PDFiumEngine::OnRightMouseDown(const pp::MouseInputEvent& event) {
       selection_.clear();
     }
 
-    SetInFormTextArea(true);
-    editable_form_text_area_ = is_editable_form_text_area;
     FORM_OnFocus(form(), page, 0, page_x, page_y);
     return true;
   }
@@ -3593,23 +3585,19 @@ void PDFiumEngine::SetMouseLeftButtonDown(bool is_mouse_left_button_down) {
   mouse_left_button_down_ = is_mouse_left_button_down;
 }
 
-bool PDFiumEngine::IsPointInEditableFormTextArea(FPDF_PAGE page,
-                                                 double page_x,
-                                                 double page_y,
-                                                 int form_type) {
+bool PDFiumEngine::IsAnnotationAnEditableFormTextArea(FPDF_ANNOTATION annot,
+                                                      int form_type) const {
 #if defined(PDF_ENABLE_XFA)
-  if (IS_XFA_FORMFIELD(form_type))
+  if (IS_XFA_FORMFIELD(form_type)) {
     return form_type == FPDF_FORMFIELD_XFA_TEXTFIELD ||
            form_type == FPDF_FORMFIELD_XFA_COMBOBOX;
+  }
 #endif  // defined(PDF_ENABLE_XFA)
 
-  const FS_POINTF point = {page_x, page_y};
-  ScopedFPDFAnnotation annot(
-      FPDFAnnot_GetFormFieldAtPoint(form(), page, &point));
   if (!annot)
     return false;
 
-  int flags = FPDFAnnot_GetFormFieldFlags(form(), annot.get());
+  int flags = FPDFAnnot_GetFormFieldFlags(form(), annot);
   return CheckIfEditableFormTextArea(flags, form_type);
 }
 
@@ -3696,6 +3684,19 @@ void PDFiumEngine::ScrollIntoView(const pp::Rect& rect) {
   }
 }
 
+void PDFiumEngine::OnFocusedAnnotationUpdated(FPDF_ANNOTATION annot) {
+  int form_type = FPDFAnnot_GetFormFieldType(form(), annot);
+  if (form_type <= FPDF_FORMFIELD_UNKNOWN) {
+    SetInFormTextArea(false);
+    return;
+  }
+  bool is_form_text_area =
+      PDFiumPage::FormTypeToArea(form_type) == PDFiumPage::FORM_TEXT_AREA;
+  SetInFormTextArea(is_form_text_area);
+  editable_form_text_area_ =
+      is_form_text_area && IsAnnotationAnEditableFormTextArea(annot, form_type);
+}
+
 void PDFiumEngine::SetCaretPosition(const pp::Point& position) {
   // TODO(dsinclair): Handle caret position ...
 }

pdf/pdfium/pdfium_engine.h

@@ -524,12 +524,10 @@ class PDFiumEngine : public PDFEngine,
   // Sets whether or not left mouse button is currently being held down.
   void SetMouseLeftButtonDown(bool is_mouse_left_button_down);
 
-  // Given coordinates on |page| has a form of |form_type| which is known to be
-  // a form text area, check if it is an editable form text area.
-  bool IsPointInEditableFormTextArea(FPDF_PAGE page,
-                                     double page_x,
-                                     double page_y,
-                                     int form_type);
+  // Given an annotation which is a form of |form_type| which is known to be a
+  // form text area, check if it is an editable form text area.
+  bool IsAnnotationAnEditableFormTextArea(FPDF_ANNOTATION annot,
+                                          int form_type) const;
 
   bool PageIndexInBounds(int index) const;
   bool IsPageCharacterIndexInBounds(
@@ -581,6 +579,8 @@ class PDFiumEngine : public PDFEngine,
   // already in view.
   void ScrollIntoView(const pp::Rect& rect);
 
+  void OnFocusedAnnotationUpdated(FPDF_ANNOTATION annot);
+
   // Fetches and populates the fields of |doc_metadata_|. To be called after the
   // document is loaded.
   void LoadDocumentMetadata();

pdf/pdfium/pdfium_engine_unittest.cc

@@ -255,6 +255,10 @@ class PDFiumEngineTabbingTest : public PDFiumTestBase {
     return engine->last_focused_annot_index_;
   }
 
+  bool IsInFormTextArea(PDFiumEngine* engine) {
+    return engine->in_form_text_area_;
+  }
+
  protected:
   base::test::TaskEnvironment task_environment_{
       base::test::TaskEnvironment::TimeSource::MOCK_TIME};
@@ -574,4 +578,39 @@ TEST_F(PDFiumEngineTabbingTest, RestoringAnnotFocusTest) {
   EXPECT_EQ(1, GetLastFocusedPage(engine.get()));
 }
 
+TEST_F(PDFiumEngineTabbingTest, VerifyFormFieldStatesOnTabbing) {
+  /*
+   * Document structure
+   * Document
+   * ++ Page 1
+   * ++++ Annotation (Text Field)
+   * ++++ Annotation (Radio Button)
+   */
+  TestClient client;
+  std::unique_ptr<PDFiumEngine> engine =
+      InitializeEngine(&client, FILE_PATH_LITERAL("annots.pdf"));
+  ASSERT_TRUE(engine);
+  ASSERT_EQ(1, engine->GetNumberOfPages());
+
+  ASSERT_TRUE(HandleTabEvent(engine.get(), 0));
+  EXPECT_EQ(PDFiumEngine::FocusElementType::kDocument,
+            GetFocusedElementType(engine.get()));
+
+  // Bring focus to the text field.
+  ASSERT_TRUE(HandleTabEvent(engine.get(), 0));
+  EXPECT_EQ(PDFiumEngine::FocusElementType::kPage,
+            GetFocusedElementType(engine.get()));
+  EXPECT_EQ(0, GetLastFocusedPage(engine.get()));
+  EXPECT_TRUE(IsInFormTextArea(engine.get()));
+  EXPECT_TRUE(engine->CanEditText());
+
+  // Bring focus to the button.
+  ASSERT_TRUE(HandleTabEvent(engine.get(), 0));
+  EXPECT_EQ(PDFiumEngine::FocusElementType::kPage,
+            GetFocusedElementType(engine.get()));
+  EXPECT_EQ(0, GetLastFocusedPage(engine.get()));
+  EXPECT_FALSE(IsInFormTextArea(engine.get()));
+  EXPECT_FALSE(engine->CanEditText());
+}
+
 }  // namespace chrome_pdf

pdf/pdfium/pdfium_form_filler.cc

@@ -293,6 +293,8 @@ void PDFiumFormFiller::Form_OnFocusChange(FPDF_FORMFILLINFO* param,
       engine->layout_.options().default_page_orientation());
 
   engine->ScrollIntoView(screen_rect);
+
+  engine->OnFocusedAnnotationUpdated(annot);
 }
 
 // static