electron/chromium_src/chrome/utility/printing_handler_win.cc

// Copyright 2014 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 "chrome/utility/printing_handler_win.h"

#include "base/files/file_util.h"
#include "base/lazy_instance.h"
#include "base/path_service.h"
#include "base/scoped_native_library.h"
#include "chrome/common/print_messages.h"
#include "content/public/utility/utility_thread.h"
#include "printing/emf_win.h"
#include "printing/page_range.h"
#include "printing/pdf_render_settings.h"
#include "ui/gfx/gdi_util.h"

namespace {

bool Send(IPC::Message* message) {
  return content::UtilityThread::Get()->Send(message);
}

void ReleaseProcessIfNeeded() {
  content::UtilityThread::Get()->ReleaseProcessIfNeeded();
}

class PdfFunctions {
 public:
  PdfFunctions() : get_pdf_doc_info_func_(NULL),
                   render_pdf_to_dc_func_(NULL) {}

  bool Init() {
    base::FilePath module_path;
    if (!PathService::Get(base::DIR_MODULE, &module_path))
      return false;
    base::FilePath::StringType name(FILE_PATH_LITERAL("pdf.dll"));
    pdf_lib_.Reset(base::LoadNativeLibrary(module_path.Append(name), NULL));
    if (!pdf_lib_.is_valid()) {
      LOG(WARNING) << "Couldn't load PDF plugin";
      return false;
    }

    get_pdf_doc_info_func_ =
        reinterpret_cast<GetPDFDocInfoProc>(
            pdf_lib_.GetFunctionPointer("GetPDFDocInfo"));
    LOG_IF(WARNING, !get_pdf_doc_info_func_) << "Missing GetPDFDocInfo";

    render_pdf_to_dc_func_ =
      reinterpret_cast<RenderPDFPageToDCProc>(
          pdf_lib_.GetFunctionPointer("RenderPDFPageToDC"));
    LOG_IF(WARNING, !render_pdf_to_dc_func_) << "Missing RenderPDFPageToDC";

    if (!get_pdf_doc_info_func_ || !render_pdf_to_dc_func_) {
      Reset();
    }

    return IsValid();
  }

  bool IsValid() const {
    return pdf_lib_.is_valid();
  }

  void Reset() {
    pdf_lib_.Reset(NULL);
  }

  bool GetPDFDocInfo(const void* pdf_buffer,
                     int buffer_size,
                     int* page_count,
                     double* max_page_width) {
    if (!get_pdf_doc_info_func_)
      return false;
    return get_pdf_doc_info_func_(pdf_buffer, buffer_size, page_count,
                                  max_page_width);
  }

  bool RenderPDFPageToDC(const void* pdf_buffer,
                         int buffer_size,
                         int page_number,
                         HDC dc,
                         int dpi,
                         int bounds_origin_x,
                         int bounds_origin_y,
                         int bounds_width,
                         int bounds_height,
                         bool fit_to_bounds,
                         bool stretch_to_bounds,
                         bool keep_aspect_ratio,
                         bool center_in_bounds,
                         bool autorotate) {
    if (!render_pdf_to_dc_func_)
      return false;
    return render_pdf_to_dc_func_(pdf_buffer, buffer_size, page_number,
                                  dc, dpi, bounds_origin_x,
                                  bounds_origin_y, bounds_width, bounds_height,
                                  fit_to_bounds, stretch_to_bounds,
                                  keep_aspect_ratio, center_in_bounds,
                                  autorotate);
  }

 private:
  // Exported by PDF plugin.
  typedef bool (*GetPDFDocInfoProc)(const void* pdf_buffer,
                                    int buffer_size, int* page_count,
                                    double* max_page_width);
  typedef bool (*RenderPDFPageToDCProc)(
      const void* pdf_buffer, int buffer_size, int page_number, HDC dc,
      int dpi, int bounds_origin_x, int bounds_origin_y,
      int bounds_width, int bounds_height, bool fit_to_bounds,
      bool stretch_to_bounds, bool keep_aspect_ratio, bool center_in_bounds,
      bool autorotate);

  RenderPDFPageToDCProc render_pdf_to_dc_func_;
  GetPDFDocInfoProc get_pdf_doc_info_func_;

  base::ScopedNativeLibrary pdf_lib_;

  DISALLOW_COPY_AND_ASSIGN(PdfFunctions);
};

base::LazyInstance<PdfFunctions> g_pdf_lib = LAZY_INSTANCE_INITIALIZER;

}  // namespace

PrintingHandlerWin::PrintingHandlerWin() {}

PrintingHandlerWin::~PrintingHandlerWin() {}

// static
void PrintingHandlerWin::PreSandboxStartup() {
  g_pdf_lib.Get().Init();
}

bool PrintingHandlerWin::OnMessageReceived(const IPC::Message& message) {
  bool handled = true;
  IPC_BEGIN_MESSAGE_MAP(PrintingHandlerWin, message)
    IPC_MESSAGE_HANDLER(ChromeUtilityMsg_RenderPDFPagesToMetafiles,
                        OnRenderPDFPagesToMetafile)
    IPC_MESSAGE_HANDLER(ChromeUtilityMsg_RenderPDFPagesToMetafiles_GetPage,
                        OnRenderPDFPagesToMetafileGetPage)
    IPC_MESSAGE_HANDLER(ChromeUtilityMsg_RenderPDFPagesToMetafiles_Stop,
                        OnRenderPDFPagesToMetafileStop)
    IPC_MESSAGE_UNHANDLED(handled = false)
  IPC_END_MESSAGE_MAP()
  return handled;
}

void PrintingHandlerWin::OnRenderPDFPagesToMetafile(
    IPC::PlatformFileForTransit pdf_transit,
    const printing::PdfRenderSettings& settings) {
  pdf_rendering_settings_ = settings;
  base::File pdf_file = IPC::PlatformFileForTransitToFile(pdf_transit);
  int page_count = LoadPDF(pdf_file.Pass());
  //int page_count = 1;
  Send(
      new ChromeUtilityHostMsg_RenderPDFPagesToMetafiles_PageCount(page_count));
}

void PrintingHandlerWin::OnRenderPDFPagesToMetafileGetPage(
    int page_number,
    IPC::PlatformFileForTransit output_file) {
  base::File emf_file = IPC::PlatformFileForTransitToFile(output_file);
  float scale_factor = 1.0f;
  bool success =
      RenderPdfPageToMetafile(page_number, emf_file.Pass(), &scale_factor);
  Send(new ChromeUtilityHostMsg_RenderPDFPagesToMetafiles_PageDone(
      success, scale_factor));
}

void PrintingHandlerWin::OnRenderPDFPagesToMetafileStop() {
  ReleaseProcessIfNeeded();
}

int PrintingHandlerWin::LoadPDF(base::File pdf_file) {
  if (!g_pdf_lib.Get().IsValid())
    return 0;

  int64 length64 = pdf_file.GetLength();
  if (length64 <= 0 || length64 > std::numeric_limits<int>::max())
    return 0;
  int length = static_cast<int>(length64);

  pdf_data_.resize(length);
  if (length != pdf_file.Read(0, pdf_data_.data(), pdf_data_.size()))
    return 0;

  int total_page_count = 0;
  if (!g_pdf_lib.Get().GetPDFDocInfo(
          &pdf_data_.front(), pdf_data_.size(), &total_page_count, NULL)) {
    return 0;
  }
  return total_page_count;
}

bool PrintingHandlerWin::RenderPdfPageToMetafile(int page_number,
                                                 base::File output_file,
                                                 float* scale_factor) {
  printing::Emf metafile;
  metafile.Init();

  // We need to scale down DC to fit an entire page into DC available area.
  // Current metafile is based on screen DC and have current screen size.
  // Writing outside of those boundaries will result in the cut-off output.
  // On metafiles (this is the case here), scaling down will still record
  // original coordinates and we'll be able to print in full resolution.
  // Before playback we'll need to counter the scaling up that will happen
  // in the service (print_system_win.cc).
  *scale_factor =
      gfx::CalculatePageScale(metafile.context(),
                              pdf_rendering_settings_.area().right(),
                              pdf_rendering_settings_.area().bottom());
  gfx::ScaleDC(metafile.context(), *scale_factor);

  // The underlying metafile is of type Emf and ignores the arguments passed
  // to StartPage.
  metafile.StartPage(gfx::Size(), gfx::Rect(), 1);
  if (!g_pdf_lib.Get().RenderPDFPageToDC(
          &pdf_data_.front(),
          pdf_data_.size(),
          page_number,
          metafile.context(),
          pdf_rendering_settings_.dpi(),
          pdf_rendering_settings_.area().x(),
          pdf_rendering_settings_.area().y(),
          pdf_rendering_settings_.area().width(),
          pdf_rendering_settings_.area().height(),
          true,
          false,
          true,
          true,
          pdf_rendering_settings_.autorotate())) {
    return false;
  }
  metafile.FinishPage();
  metafile.FinishDocument();
  return metafile.SaveTo(&output_file);
}