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>

1 files changed, 18 insertions, 0 deletions

diff --git a/fpdfsdk/fpdfformfill.cpp b/fpdfsdk/fpdfformfill.cpp
index 717e9722af..08d3d30847 100644
--- a/fpdfsdk/fpdfformfill.cpp
+++ b/fpdfsdk/fpdfformfill.cpp
@@ -369,6 +369,24 @@ DLLEXPORT FPDF_BOOL STDCALL FORM_OnChar(FPDF_FORMHANDLE hHandle,
   return pPageView->OnChar(nChar, modifier);
 }
 
+DLLEXPORT unsigned long STDCALL FORM_GetSelectedText(FPDF_FORMHANDLE hHandle,
+                                                     FPDF_PAGE page,
+                                                     void* buffer,
+                                                     unsigned long buflen) {
+  CPDFSDK_PageView* pPageView = FormHandleToPageView(hHandle, page);
+  if (!pPageView)
+    return 0;
+
+  CFX_WideString wide_str_form_text = pPageView->GetSelectedText();
+  CFX_ByteString encoded_form_text = wide_str_form_text.UTF16LE_Encode();
+  unsigned long form_text_len = encoded_form_text.GetLength();
+
+  if (buffer && buflen >= form_text_len)
+    memcpy(buffer, encoded_form_text.c_str(), form_text_len);
+
+  return form_text_len;
+}
+
 DLLEXPORT FPDF_BOOL STDCALL FORM_ForceToKillFocus(FPDF_FORMHANDLE hHandle) {
   CPDFSDK_FormFillEnvironment* pFormFillEnv =
       HandleToCPDFSDKEnvironment(hHandle);