Add functionality for copying text within form text fields and form combobox text fields

pdf/pdfium/pdfium_engine.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 1606 matching lines @@
       FPDF_PAGE page = FPDF_LoadPage(doc, i);
       TransformPDFPageForPrinting(page, print_settings);
       FPDF_ClosePage(page);
     }
   }
 }
 
 void PDFiumEngine::SaveSelectedFormForPrint() {
   FORM_ForceToKillFocus(form_);
   client_->FormTextFieldFocusChange(false);
+  SetInFormTextField(false);
+}
+
+void PDFiumEngine::SetFormSelectedText(const FPDF_FORMHANDLE& hHandle,
+                                       const FPDF_PAGE& page) {
+  size_t form_sel_text_len = FORM_GetSelectedText(hHandle, page, nullptr, 0);
+  if (!form_sel_text_len)
+    return;
+
+  base::string16 selected_form_text16;
+  PDFiumAPIStringBufferSizeInBytesAdapter<base::string16> string_adapter(
+      &selected_form_text16, form_sel_text_len, false);
+  string_adapter.Close(FORM_GetSelectedText(
+      hHandle, page, string_adapter.GetData(), form_sel_text_len));
+
+  std::string selected_form_text = UTF16ToUTF8(selected_form_text16);
+  if (!selected_form_text.empty()) {
+    pp::PDF::SetSelectedText(GetPluginInstance(), selected_form_text.c_str());
+  }
 }
 
 void PDFiumEngine::PrintEnd() {
   FORM_DoDocumentAAction(form_, FPDFDOC_AACTION_DP);
 }
 
 PDFiumPage::Area PDFiumEngine::GetCharIndex(const pp::MouseInputEvent& event,
                                             int* page_index,
                                             int* char_index,
                                             int* form_type,
@@ skipping 76 matching lines @@
     return false;
 
   if (page_index != -1) {
     last_page_mouse_down_ = page_index;
     double page_x, page_y;
     pp::Point point = event.GetPosition();
     DeviceToPage(page_index, point.x(), point.y(), &page_x, &page_y);
 
     FORM_OnLButtonDown(form_, pages_[page_index]->GetPage(), 0, page_x, page_y);
     if (form_type > FPDF_FORMFIELD_UNKNOWN) {  // returns -1 sometimes...
-      mouse_down_state_.Set(PDFiumPage::NONSELECTABLE_AREA, target);
+      mouse_down_state_.Set(PDFiumPage::FORM_TEXT_AREA, target);

[Lei Zhang, 2017/06/14 07:07:02]

If we click on a form widget that is not a form text area, is this the right
type to set?

[drgage, 2017/06/14 22:53:39]

Probably not - I'll change this so that it only is set to FORM_TEXT_AREA if the
form_type == FPDF_FORMFIELD_TEXTFIELD.

[drgage, 2017/06/14 22:53:39]

Done.

       bool is_valid_control = (form_type == FPDF_FORMFIELD_TEXTFIELD ||
                                form_type == FPDF_FORMFIELD_COMBOBOX);
 #if defined(PDF_ENABLE_XFA)
       is_valid_control |= (form_type == FPDF_FORMFIELD_XFA);
 #endif
       client_->FormTextFieldFocusChange(is_valid_control);
+
+      // TODO (drgage): come back here and figure out what to do with

[Lei Zhang, 2017/06/14 07:07:02]

I think this is actually correct as is in the non-XFA case. BTW, I referred to
the combo box as drop down control.

It looks like Acrobat Reader can copy text from these two types of fields, so we
should as well. We can work on making combo boxes actually work separately. (XFA
will be even more work to figure out. Maybe leave a TODO(bug_62400) here for
XFA?)

[drgage, 2017/06/14 22:53:39]

Done.

+      // is_valid_control
+      SetInFormTextField(is_valid_control);
       return true;  // Return now before we get into the selection code.
     }
   }
 
   client_->FormTextFieldFocusChange(false);
+  SetInFormTextField(false);
 
   if (area != PDFiumPage::TEXT_AREA)
     return true;  // Return true so WebKit doesn't do its own highlighting.
 
   if (event.GetClickCount() == 1) {
     OnSingleClick(page_index, char_index);
   } else if (event.GetClickCount() == 2 || event.GetClickCount() == 3) {
     OnMultipleClick(event.GetClickCount(), page_index, char_index);
   }
 
@@ skipping 55 matching lines @@
       bool alt_key = !!(modifiers & PP_INPUTEVENT_MODIFIER_ALTKEY);
       bool ctrl_key = !!(modifiers & PP_INPUTEVENT_MODIFIER_CONTROLKEY);
       bool meta_key = !!(modifiers & PP_INPUTEVENT_MODIFIER_METAKEY);
       bool shift_key = !!(modifiers & PP_INPUTEVENT_MODIFIER_SHIFTKEY);
 
       WindowOpenDisposition disposition = ui::DispositionFromClick(
           middle_button, alt_key, ctrl_key, meta_key, shift_key);
 
       client_->NavigateTo(target.url, disposition);
       client_->FormTextFieldFocusChange(false);
+      SetInFormTextField(false);
       return true;
     }
     if (area == PDFiumPage::DOCLINK_AREA) {
       client_->ScrollToPage(target.page);
       client_->FormTextFieldFocusChange(false);
+      SetInFormTextField(false);
       return true;
     }
   }
 
   // Prevent middle mouse button from selecting texts.
   if (event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_MIDDLE)
     return false;
 
   if (page_index != -1) {
     double page_x, page_y;
     pp::Point point = event.GetPosition();
     DeviceToPage(page_index, point.x(), point.y(), &page_x, &page_y);
     FORM_OnLButtonUp(form_, pages_[page_index]->GetPage(), 0, page_x, page_y);
   }
 
+  if (area == PDFiumPage::FORM_TEXT_AREA) {
+    SetFormSelectedText(form_, pages_[last_page_mouse_down_]->GetPage());
+  }
+
   if (!selecting_)

[Lei Zhang, 2017/06/14 07:07:02]

The existing code like this member variable and SetSelecting() can use some
updated comments to better explain what they select.

[drgage, 2017/06/14 22:53:40]

Done. Do you think it's sufficient to add an explanation for these in
pdfium_engine.h? I can also add a comment here, but I can make it clear that
selection_ is used for text selection.

     return false;
 
   SetSelecting(false);
   return true;
 }
 
 bool PDFiumEngine::OnMouseMove(const pp::MouseInputEvent& event) {
   int page_index = -1;
   int char_index = -1;
   int form_type = FPDF_FORMFIELD_UNKNOWN;
@@ skipping 10 matching lines @@
     PP_CursorType_Dev cursor;
     switch (area) {
       case PDFiumPage::TEXT_AREA:
         cursor = PP_CURSORTYPE_IBEAM;
         break;
       case PDFiumPage::WEBLINK_AREA:
       case PDFiumPage::DOCLINK_AREA:
         cursor = PP_CURSORTYPE_HAND;
         break;
       case PDFiumPage::NONSELECTABLE_AREA:
       default:

[Lei Zhang, 2017/06/14 07:07:02]

Let's handle FORM_TEXT_AREA explicitly here too.

[drgage, 2017/06/14 22:53:39]

Do you think I should just add another case without a break statement? Did you
have anything else in mind?

[Lei Zhang, 2017/06/15 18:11:28]

Add another case without a break.

[drgage, 2017/06/16 02:12:36]

Done.

         switch (form_type) {
           case FPDF_FORMFIELD_PUSHBUTTON:
           case FPDF_FORMFIELD_CHECKBOX:
           case FPDF_FORMFIELD_RADIOBUTTON:
           case FPDF_FORMFIELD_COMBOBOX:
           case FPDF_FORMFIELD_LISTBOX:
             cursor = PP_CURSORTYPE_HAND;
             break;
           case FPDF_FORMFIELD_TEXTFIELD:
             cursor = PP_CURSORTYPE_IBEAM;
@@ skipping 112 matching lines @@
     OnChar(synthesized);
   }
 
   return rv;
 }
 
 bool PDFiumEngine::OnKeyUp(const pp::KeyboardInputEvent& event) {
   if (last_page_mouse_down_ == -1)
     return false;
 
+  if (in_form_text_field_) {
+    uint32_t modifiers = event.GetModifiers();
+    if (modifiers & PP_INPUTEVENT_MODIFIER_SHIFTKEY)

[Lei Zhang, 2017/06/14 07:07:02]

I tried this code out and noticed if I:
1) used the shift + arrow keys to select some text
2) stopped holding shift
3) used the arrow keys to move around

Then the selection disappears visually, but remains as far as the selection code
for copying is concerned.

[drgage, 2017/06/14 22:53:39]

I see what you mean. I hadn't tried this combination of actions. The same thing
happens if you press any other key, like if you type another letter and erase
what was there, the old selected text is still available for copying just
because the shift key was released. The same thing also happens with the mouse
selection. If you have something selected with the mouse, then press a key, the
visual selection disappears but you can still copy the old selected text.

I can look into how the visual selection code works and try to fix this. 

As far as text selection (i.e. via the selection_ vector for
PDFiumPage::TEXT_AREA text) is concerned, you can't select using the shift and
arrow keys at all, and if you select with the mouse and then press the arrow
keys, the current selection doesn't visually change/disappear, so this isn't a
problem there. I'm thinking another option for handling this bug would be to
mimic this behavior and prevent the visual selection from changing if you press
a key within a form text field when you have text selected, but I don't think
this is a great choice for user experience, so I'm going to look into how the
visual selection code works.

[Lei Zhang, 2017/06/15 18:11:28]

I don't think you need to actually know how the visual selection works. Just
look at how pp::PDF::SetSelectedText() gets called when there is a non-form text
selection, and one does a mouse click to clear that selection.

[drgage, 2017/06/16 02:12:36]

Done.

+      SetFormSelectedText(form_, pages_[last_page_mouse_down_]->GetPage());
+  }
+
   return !!FORM_OnKeyUp(form_, pages_[last_page_mouse_down_]->GetPage(),
                         event.GetKeyCode(), event.GetModifiers());
 }
 
 bool PDFiumEngine::OnChar(const pp::KeyboardInputEvent& event) {
   if (last_page_mouse_down_ == -1)
     return false;
 
   base::string16 str = base::UTF8ToUTF16(event.GetCharacterText().AsString());
   return !!FORM_OnChar(form_, pages_[last_page_mouse_down_]->GetPage(), str[0],
@@ skipping 1541 matching lines @@
   client_->ScrollToPage(most_visible_page);
 }
 
 void PDFiumEngine::SetSelecting(bool selecting) {
   bool was_selecting = selecting_;
   selecting_ = selecting;
   if (selecting_ != was_selecting)
     client_->IsSelectingChanged(selecting);
 }
 
+void PDFiumEngine::SetInFormTextField(bool in_form_text_field) {
+  in_form_text_field_ = in_form_text_field;
+}
+
 void PDFiumEngine::ScheduleTouchTimer(const pp::TouchInputEvent& evt) {
   touch_timers_[++next_touch_timer_id_] = evt;
   client_->ScheduleTouchTimerCallback(next_touch_timer_id_,
                                       kTouchLongPressTimeoutMs);
 }
 
 void PDFiumEngine::KillTouchTimer(int timer_id) {
   touch_timers_.erase(timer_id);
 }
 
@@ skipping 569 matching lines @@
   FPDF_DOCUMENT doc =
       FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, nullptr);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf