electron/shell/browser/printing/printing_utils.cc

134 lines
4.5 KiB
C++

// Copyright (c) 2024 Microsoft, GmbH.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#include "shell/browser/printing/printing_utils.h"
#include "base/apple/scoped_typeref.h"
#include "base/strings/sys_string_conversions.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task/task_traits.h"
#include "base/task/thread_pool.h"
#include "chrome/browser/browser_process.h"
#include "content/public/browser/browser_thread.h"
#include "electron/buildflags/buildflags.h"
#include "printing/backend/print_backend.h" // nogncheck
#include "printing/units.h"
#include "shell/common/thread_restrictions.h"
#if BUILDFLAG(IS_MAC)
#include <ApplicationServices/ApplicationServices.h>
#endif
#if BUILDFLAG(IS_LINUX)
#include <gtk/gtk.h>
#endif
#if BUILDFLAG(IS_WIN)
#include <windows.h>
#endif
namespace electron {
gfx::Size GetDefaultPrinterDPI(const std::u16string& device_name) {
#if BUILDFLAG(IS_MAC)
return gfx::Size(printing::kDefaultMacDpi, printing::kDefaultMacDpi);
#elif BUILDFLAG(IS_WIN)
HDC hdc =
CreateDC(L"WINSPOOL", base::as_wcstr(device_name), nullptr, nullptr);
if (hdc == nullptr)
return gfx::Size(printing::kDefaultPdfDpi, printing::kDefaultPdfDpi);
int dpi_x = GetDeviceCaps(hdc, LOGPIXELSX);
int dpi_y = GetDeviceCaps(hdc, LOGPIXELSY);
DeleteDC(hdc);
return gfx::Size(dpi_x, dpi_y);
#else
GtkPrintSettings* print_settings = gtk_print_settings_new();
int dpi = gtk_print_settings_get_resolution(print_settings);
g_object_unref(print_settings);
return gfx::Size(dpi, dpi);
#endif
}
bool IsDeviceNameValid(const std::u16string& device_name) {
#if BUILDFLAG(IS_MAC)
base::apple::ScopedCFTypeRef<CFStringRef> new_printer_id(
base::SysUTF16ToCFStringRef(device_name));
PMPrinter new_printer = PMPrinterCreateFromPrinterID(new_printer_id.get());
bool printer_exists = new_printer != nullptr;
PMRelease(new_printer);
return printer_exists;
#else
scoped_refptr<printing::PrintBackend> print_backend =
printing::PrintBackend::CreateInstance(
g_browser_process->GetApplicationLocale());
return print_backend->IsValidPrinter(base::UTF16ToUTF8(device_name));
#endif
}
std::pair<std::string, std::u16string> GetDeviceNameToUse(
const std::u16string& device_name) {
#if BUILDFLAG(IS_WIN)
// Blocking is needed here because Windows printer drivers are oftentimes
// not thread-safe and have to be accessed on the UI thread.
ScopedAllowBlockingForElectron allow_blocking;
#endif
if (!device_name.empty()) {
if (!IsDeviceNameValid(device_name))
return std::make_pair("Invalid deviceName provided", std::u16string());
return std::make_pair(std::string(), device_name);
}
scoped_refptr<printing::PrintBackend> print_backend =
printing::PrintBackend::CreateInstance(
g_browser_process->GetApplicationLocale());
std::string printer_name;
printing::mojom::ResultCode code =
print_backend->GetDefaultPrinterName(printer_name);
// We don't want to return if this fails since some devices won't have a
// default printer.
if (code != printing::mojom::ResultCode::kSuccess)
LOG(ERROR) << "Failed to get default printer name";
if (printer_name.empty()) {
printing::PrinterList printers;
if (print_backend->EnumeratePrinters(printers) !=
printing::mojom::ResultCode::kSuccess)
return std::make_pair("Failed to enumerate printers", std::u16string());
if (printers.empty())
return std::make_pair("No printers available on the network",
std::u16string());
printer_name = printers.front().printer_name;
}
return std::make_pair(std::string(), base::UTF8ToUTF16(printer_name));
}
// Copied from
// chrome/browser/ui/webui/print_preview/local_printer_handler_default.cc:L36-L54
scoped_refptr<base::TaskRunner> CreatePrinterHandlerTaskRunner() {
// USER_VISIBLE because the result is displayed in the print preview dialog.
#if !BUILDFLAG(IS_WIN)
static constexpr base::TaskTraits kTraits = {
base::MayBlock(), base::TaskPriority::USER_VISIBLE};
#endif
#if defined(USE_CUPS)
// CUPS is thread safe.
return base::ThreadPool::CreateTaskRunner(kTraits);
#elif BUILDFLAG(IS_WIN)
// Windows drivers are likely not thread-safe and need to be accessed on the
// UI thread.
return content::GetUIThreadTaskRunner({base::TaskPriority::USER_VISIBLE});
#else
// Be conservative on unsupported platforms.
return base::ThreadPool::CreateSingleThreadTaskRunner(kTraits);
#endif
}
} // namespace electron