Shift-Click doesn't extend selection in internal PDF plugin

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 "base/json/json_writer.h"
 #include "base/logging.h"
@@ skipping 582 matching lines @@
       last_character_index_to_search_(-1),
       permissions_(0),
       fpdf_availability_(NULL),
       next_timer_id_(0),
       last_page_mouse_down_(-1),
       first_visible_page_(-1),
       most_visible_page_(-1),
       called_do_document_action_(false),
       render_grayscale_(false),
       progressive_paint_timeout_(0),
-      getting_password_(false) {
+      getting_password_(false),
+      last_char_index_(-1) {
   find_factory_.Initialize(this);
   password_factory_.Initialize(this);
 
   file_access_.m_FileLen = 0;
   file_access_.m_GetBlock = &GetBlock;
   file_access_.m_Param = &doc_loader_;
 
   file_availability_.version = 1;
   file_availability_.IsDataAvail = &IsDataAvail;
   file_availability_.loader = &doc_loader_;
@@ skipping 1072 matching lines @@
   // mouse move events.
   if (area == PDFiumPage::WEBLINK_AREA)
     return true;
 
   if (area == PDFiumPage::DOCLINK_AREA) {
     client_->ScrollToPage(target.page);
     client_->FormTextFieldFocusChange(false);
     return true;
   }
 
+  int last_page_index = last_page_mouse_down_;
   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);
     int control = FPDPage_HasFormFieldAtPoint(
         form_, pages_[page_index]->GetPage(), page_x, page_y);
     if (control > FPDF_FORMFIELD_UNKNOWN) {  // returns -1 sometimes...
 #ifdef PDF_USE_XFA
     client_->FormTextFieldFocusChange(control == FPDF_FORMFIELD_TEXTFIELD ||
         control == FPDF_FORMFIELD_COMBOBOX || control == FPDF_FORMFIELD_XFA);
 #else
     client_->FormTextFieldFocusChange(control == FPDF_FORMFIELD_TEXTFIELD ||
         control == FPDF_FORMFIELD_COMBOBOX);
 #endif
       return true;  // Return now before we get into the selection code.
     }
   }
 
   client_->FormTextFieldFocusChange(false);
+  if (event.GetModifiers() == (PP_INPUTEVENT_MODIFIER_LEFTBUTTONDOWN |
+                               PP_INPUTEVENT_MODIFIER_SHIFTKEY) &&
+      event.GetClickCount() == 1) {
+    HandleShiftClick(last_page_index, page_index, char_index);
+    last_char_index_ = char_index;
+    return true;
+  }
+
+  last_char_index_ = char_index;
 
   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 1734 matching lines @@
 
   InvalidateAllPages();
 
   if (!current_find_text.empty()) {
     // Clear the UI.
     client_->NotifyNumberOfFindResultsChanged(0, false);
     StartFind(current_find_text.c_str(), false);
   }
 }
 
+void PDFiumEngine::HandleShiftClick(const int last_page_index,
+                                    const int page_index,
+                                    const int char_index) {
+  selecting_ = true;
+  if (last_page_index == -1 || last_page_index == page_index) {
+    if (last_char_index_ != -1) {
+      if (char_index == -1) {
+        selection_.push_back(
+            PDFiumRange(pages_[page_index], 0, last_char_index_ + 1));
+      } else {
+        if (char_index > last_char_index_) {
+          selection_.push_back(PDFiumRange(pages_[page_index], last_char_index_,
+                                           char_index - last_char_index_ + 1));
+        } else if (char_index < last_char_index_) {
+          selection_.push_back(PDFiumRange(pages_[page_index], char_index,
+                                           last_char_index_ - char_index + 1));
+        }
+      }
+    } else {
+      if (char_index != -1)
+        selection_.push_back(
+            PDFiumRange(pages_[page_index], 0, char_index + 1));
+    }
+  } else {
+    if (last_char_index_ != -1 && char_index != -1) {
+      if (last_page_index < page_index) {
+        selection_.push_back(
+            PDFiumRange(pages_[last_page_index], last_char_index_,
+                        pages_[last_page_index]->GetCharCount()));
+        for (int i = last_page_index + 1; i < page_index; i++) {
+          selection_.push_back(
+              PDFiumRange(pages_[i], 0, pages_[i]->GetCharCount()));
+        }
+        selection_.push_back(
+            PDFiumRange(pages_[page_index], 0, char_index + 1));
+      } else {
+        selection_.push_back(PDFiumRange(pages_[page_index], char_index,
+                                         pages_[page_index]->GetCharCount()));
+        for (int i = page_index + 1; i < last_page_index; i++) {
+          selection_.push_back(
+              PDFiumRange(pages_[i], 0, pages_[i]->GetCharCount()));
+        }
+        selection_.push_back(
+            PDFiumRange(pages_[last_page_index], 0, last_char_index_ + 1));
+      }
+    }
+  }
+}
+
 void PDFiumEngine::Form_Invalidate(FPDF_FORMFILLINFO* param,
                                    FPDF_PAGE page,
                                    double left,
                                    double top,
                                    double right,
                                    double bottom) {
   PDFiumEngine* engine = static_cast<PDFiumEngine*>(param);
   int page_index = engine->GetVisiblePageIndex(page);
   if (page_index == -1) {
     // This can sometime happen when the page is closed because it went off
@@ skipping 536 matching lines @@
     double* height) {
   FPDF_DOCUMENT doc = FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, NULL);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf