Add FORM_GetSelectedText() function.

This function copies the selected text from a form text field or
form combobox text field into the buffer parameter and returns the
length of the selected text string. When buffer is a nullptr or
buflen is less than the length of the selected text, this function
does not modify the buffer and only returns the selected text length.

BUG=chromium:59266

Change-Id: Ie77de38e45bbe6f9ea033826c961435304eedfc7
Reviewed-on: https://pdfium-review.googlesource.com/6413
Reviewed-by: dsinclair <dsinclair@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

7 files changed, 122 insertions, 37 deletions

diff --git a/fpdfsdk/pdfwindow/cpwl_combo_box.cpp b/fpdfsdk/pdfwindow/cpwl_combo_box.cpp
index b69f98906e..2929aac90f 100644
--- a/fpdfsdk/pdfwindow/cpwl_combo_box.cpp
+++ b/fpdfsdk/pdfwindow/cpwl_combo_box.cpp
@@ -216,6 +216,13 @@ void CPWL_ComboBox::KillFocus() {
   CPWL_Wnd::KillFocus();
 }
 
+CFX_WideString CPWL_ComboBox::GetSelectedText() {
+  if (m_pEdit)
+    return m_pEdit->GetSelectedText();
+
+  return CFX_WideString();
+}
+
 CFX_WideString CPWL_ComboBox::GetText() const {
   if (m_pEdit) {
     return m_pEdit->GetText();
diff --git a/fpdfsdk/pdfwindow/cpwl_combo_box.h b/fpdfsdk/pdfwindow/cpwl_combo_box.h
index e814ca5d40..549374f3e8 100644
--- a/fpdfsdk/pdfwindow/cpwl_combo_box.h
+++ b/fpdfsdk/pdfwindow/cpwl_combo_box.h
@@ -69,6 +69,7 @@ class CPWL_ComboBox : public CPWL_Wnd {
   CFX_FloatRect GetFocusRect() const override;
   void SetFocus() override;
   void KillFocus() override;
+  CFX_WideString GetSelectedText() override;
 
   void SetFillerNotify(IPWL_Filler_Notify* pNotify);
 
diff --git a/fpdfsdk/pdfwindow/cpwl_edit_ctrl.cpp b/fpdfsdk/pdfwindow/cpwl_edit_ctrl.cpp
index 9c22cead58..3390696e01 100644
--- a/fpdfsdk/pdfwindow/cpwl_edit_ctrl.cpp
+++ b/fpdfsdk/pdfwindow/cpwl_edit_ctrl.cpp
@@ -53,6 +53,13 @@ void CPWL_EditCtrl::SetCursor() {
   }
 }
 
+CFX_WideString CPWL_EditCtrl::GetSelectedText() {
+  if (m_pEdit)
+    return m_pEdit->GetSelText();
+
+  return CFX_WideString();
+}
+
 void CPWL_EditCtrl::RePosChildWnd() {
   m_pEdit->SetPlateRect(GetClientRect());
 }
diff --git a/fpdfsdk/pdfwindow/cpwl_edit_ctrl.h b/fpdfsdk/pdfwindow/cpwl_edit_ctrl.h
index 59bb623776..1c4c92507a 100644
--- a/fpdfsdk/pdfwindow/cpwl_edit_ctrl.h
+++ b/fpdfsdk/pdfwindow/cpwl_edit_ctrl.h
@@ -61,6 +61,7 @@ class CPWL_EditCtrl : public CPWL_Wnd {
   void SetFontSize(float fFontSize) override;
   float GetFontSize() const override;
   void SetCursor() override;
+  CFX_WideString GetSelectedText() override;
 
   void IOnSetScrollInfoY(float fPlateMin,
                          float fPlateMax,
diff --git a/fpdfsdk/pdfwindow/cpwl_edit_embeddertest.cpp b/fpdfsdk/pdfwindow/cpwl_edit_embeddertest.cpp
index 4a14b65d0d..e206cd16e3 100644
--- a/fpdfsdk/pdfwindow/cpwl_edit_embeddertest.cpp
+++ b/fpdfsdk/pdfwindow/cpwl_edit_embeddertest.cpp
@@ -11,51 +11,115 @@
 #include "testing/embedder_test.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-class CPWLEditEmbeddertest : public EmbedderTest {};
+class CPWLEditEmbeddertest : public EmbedderTest {
+ protected:
+  void SetUp() override {
+    EmbedderTest::SetUp();
+    CreateAndInitializeFormPDF();
+  }
 
-TEST_F(CPWLEditEmbeddertest, TypeText) {
-  EXPECT_TRUE(OpenDocument("text_form.pdf"));
-  FPDF_PAGE page = LoadPage(0);
-  ASSERT_TRUE(page);
-
-  CPDFSDK_FormFillEnvironment* pFormFillEnv =
-      static_cast<CPDFSDK_FormFillEnvironment*>(form_handle());
-
-  CPDFSDK_Annot* pAnnot;
-  {
-    CBA_AnnotIterator iter(pFormFillEnv->GetPageView(0),
-                           CPDF_Annot::Subtype::WIDGET);
-    pAnnot = iter.GetFirstAnnot();
-    CPDFSDK_Annot* pLastAnnot = iter.GetLastAnnot();
-    ASSERT_EQ(pAnnot, pLastAnnot);
-    ASSERT_TRUE(pAnnot);
-    ASSERT_EQ(CPDF_Annot::Subtype::WIDGET, pAnnot->GetAnnotSubtype());
+  void TearDown() override {
+    UnloadPage(GetPage());
+    EmbedderTest::TearDown();
   }
 
-  CFFL_InteractiveFormFiller* pInteractiveFormFiller =
-      pFormFillEnv->GetInteractiveFormFiller();
-  {
-    CPDFSDK_Annot::ObservedPtr pObserved(pAnnot);
-    EXPECT_TRUE(pInteractiveFormFiller->OnSetFocus(&pObserved, 0));
+  void CreateAndInitializeFormPDF() {
+    EXPECT_TRUE(OpenDocument("text_form.pdf"));
+    m_page = LoadPage(0);
+    ASSERT_TRUE(m_page);
+
+    CPDFSDK_FormFillEnvironment* pFormFillEnv =
+        static_cast<CPDFSDK_FormFillEnvironment*>(form_handle());
+
+    {
+      CBA_AnnotIterator iter(pFormFillEnv->GetPageView(0),
+                             CPDF_Annot::Subtype::WIDGET);
+      m_pAnnot = iter.GetFirstAnnot();
+      CPDFSDK_Annot* pLastAnnot = iter.GetLastAnnot();
+      ASSERT_EQ(m_pAnnot, pLastAnnot);
+      ASSERT_TRUE(m_pAnnot);
+      ASSERT_EQ(CPDF_Annot::Subtype::WIDGET, m_pAnnot->GetAnnotSubtype());
+    }
+
+    CFFL_InteractiveFormFiller* pInteractiveFormFiller =
+        pFormFillEnv->GetInteractiveFormFiller();
+    {
+      CPDFSDK_Annot::ObservedPtr pObserved(m_pAnnot);
+      EXPECT_TRUE(pInteractiveFormFiller->OnSetFocus(&pObserved, 0));
+    }
+
+    m_pFormFiller = pInteractiveFormFiller->GetFormFiller(m_pAnnot, false);
+    ASSERT_TRUE(m_pFormFiller);
+
+    CPWL_Wnd* pWindow =
+        m_pFormFiller->GetPDFWindow(pFormFillEnv->GetPageView(0), false);
+    ASSERT_TRUE(pWindow);
+    ASSERT_EQ(PWL_CLASSNAME_EDIT, pWindow->GetClassName());
+
+    m_pEdit = static_cast<CPWL_Edit*>(pWindow);
   }
 
-  CFFL_FormFiller* pFormFiller =
-      pInteractiveFormFiller->GetFormFiller(pAnnot, false);
-  ASSERT_TRUE(pFormFiller);
+  FPDF_PAGE GetPage() { return m_page; }
+  CPWL_Edit* GetCPWLEdit() { return m_pEdit; }
+  CFFL_FormFiller* GetCFFLFormFiller() { return m_pFormFiller; }
+  CPDFSDK_Annot* GetCPDFSDKAnnot() { return m_pAnnot; }
+
+ private:
+  FPDF_PAGE m_page;
+  CPWL_Edit* m_pEdit;
+  CFFL_FormFiller* m_pFormFiller;
+  CPDFSDK_Annot* m_pAnnot;
+};
+
+TEST_F(CPWLEditEmbeddertest, TypeText) {
+  EXPECT_TRUE(GetCPWLEdit()->GetText().IsEmpty());
+  EXPECT_TRUE(GetCFFLFormFiller()->OnChar(GetCPDFSDKAnnot(), 'a', 0));
+  EXPECT_TRUE(GetCFFLFormFiller()->OnChar(GetCPDFSDKAnnot(), 'b', 0));
+  EXPECT_TRUE(GetCFFLFormFiller()->OnChar(GetCPDFSDKAnnot(), 'c', 0));
+
+  EXPECT_STREQ(L"abc", GetCPWLEdit()->GetText().c_str());
+}
+
+TEST_F(CPWLEditEmbeddertest, GetSelectedTextEmptyAndBasic) {
+  // Attempt to set selection before text has been typed to test that
+  // selection is identified as empty.
+  //
+  // Select from character index [0, 3) within form text field.
+  GetCPWLEdit()->SetSel(0, 3);
+  EXPECT_TRUE(GetCPWLEdit()->GetSelectedText().IsEmpty());
+
+  EXPECT_TRUE(GetCFFLFormFiller()->OnChar(GetCPDFSDKAnnot(), 'a', 0));
+  EXPECT_TRUE(GetCFFLFormFiller()->OnChar(GetCPDFSDKAnnot(), 'b', 0));
+  EXPECT_TRUE(GetCFFLFormFiller()->OnChar(GetCPDFSDKAnnot(), 'c', 0));
+  GetCPWLEdit()->SetSel(0, 2);
+
+  EXPECT_STREQ(L"ab", GetCPWLEdit()->GetSelectedText().c_str());
+}
+
+TEST_F(CPWLEditEmbeddertest, GetSelectedTextFragments) {
+  for (int i = 0; i < 50; ++i) {
+    EXPECT_TRUE(GetCFFLFormFiller()->OnChar(GetCPDFSDKAnnot(), i + 'A', 0));
+  }
+
+  GetCPWLEdit()->SetSel(0, 0);
+  EXPECT_TRUE(GetCPWLEdit()->GetSelectedText().IsEmpty());
+
+  GetCPWLEdit()->SetSel(0, 1);
+  EXPECT_STREQ(L"A", GetCPWLEdit()->GetSelectedText().c_str());
 
-  CPWL_Wnd* pWindow =
-      pFormFiller->GetPDFWindow(pFormFillEnv->GetPageView(0), false);
-  ASSERT_TRUE(pWindow);
-  ASSERT_EQ(PWL_CLASSNAME_EDIT, pWindow->GetClassName());
+  GetCPWLEdit()->SetSel(0, -1);
+  EXPECT_STREQ(L"ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqr",
+               GetCPWLEdit()->GetSelectedText().c_str());
 
-  CPWL_Edit* pEdit = static_cast<CPWL_Edit*>(pWindow);
-  EXPECT_TRUE(pEdit->GetText().IsEmpty());
+  GetCPWLEdit()->SetSel(-8, -1);
+  EXPECT_TRUE(GetCPWLEdit()->GetSelectedText().IsEmpty());
 
-  EXPECT_TRUE(pFormFiller->OnChar(pAnnot, 'a', 0));
-  EXPECT_TRUE(pFormFiller->OnChar(pAnnot, 'b', 0));
-  EXPECT_TRUE(pFormFiller->OnChar(pAnnot, 'c', 0));
+  GetCPWLEdit()->SetSel(23, 12);
+  EXPECT_STREQ(L"MNOPQRSTUVW", GetCPWLEdit()->GetSelectedText().c_str());
 
-  EXPECT_STREQ(L"abc", pEdit->GetText().c_str());
+  GetCPWLEdit()->SetSel(12, 23);
+  EXPECT_STREQ(L"MNOPQRSTUVW", GetCPWLEdit()->GetSelectedText().c_str());
 
-  UnloadPage(page);
+  GetCPWLEdit()->SetSel(49, 50);
+  EXPECT_STREQ(L"r", GetCPWLEdit()->GetSelectedText().c_str());
 }
diff --git a/fpdfsdk/pdfwindow/cpwl_wnd.cpp b/fpdfsdk/pdfwindow/cpwl_wnd.cpp
index 90a79305eb..d44b219110 100644
--- a/fpdfsdk/pdfwindow/cpwl_wnd.cpp
+++ b/fpdfsdk/pdfwindow/cpwl_wnd.cpp
@@ -390,6 +390,10 @@ PWL_IMPLEMENT_MOUSE_METHOD(OnRButtonUp)
 PWL_IMPLEMENT_MOUSE_METHOD(OnMouseMove)
 #undef PWL_IMPLEMENT_MOUSE_METHOD
 
+CFX_WideString CPWL_Wnd::GetSelectedText() {
+  return CFX_WideString();
+}
+
 bool CPWL_Wnd::OnMouseWheel(short zDelta,
                             const CFX_PointF& point,
                             uint32_t nFlag) {
diff --git a/fpdfsdk/pdfwindow/cpwl_wnd.h b/fpdfsdk/pdfwindow/cpwl_wnd.h
index e7a4e23c38..704984932b 100644
--- a/fpdfsdk/pdfwindow/cpwl_wnd.h
+++ b/fpdfsdk/pdfwindow/cpwl_wnd.h
@@ -229,6 +229,7 @@ class CPWL_Wnd : public CPWL_TimerHandler {
   virtual void SetFontSize(float fFontSize);
   virtual float GetFontSize() const;
 
+  virtual CFX_WideString GetSelectedText();
   virtual CFX_FloatRect GetFocusRect() const;
   virtual CFX_FloatRect GetClientRect() const;