Stub for ARC print Bridge

chrome/browser/chromeos/arc/arc_print_service.cc

+// Copyright 2016 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/browser/chromeos/arc/arc_print_service.h"
+
+#include <utility>
+
+#include "ash/common/shell_delegate.h"
+#include "ash/common/wm_shell.h"
+#include "ash/new_window_delegate.h"
+#include "ash/shell.h"
+#include "base/files/file.h"
+#include "base/files/scoped_file.h"
+#include "base/logging.h"
+#include "base/optional.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_checker.h"
+#include "components/arc/arc_bridge_service.h"
+#include "content/public/browser/browser_thread.h"
+#include "mojo/edk/embedder/embedder.h"
+#include "net/base/filename_util.h"
+#include "url/gurl.h"
+
+namespace {
+
+class ScopedTempFile {
+ public:
+  ScopedTempFile() { base::CreateTemporaryFile(&file_path_); }
+  ~ScopedTempFile() {
+    // TODO(poromov) Delete file after printing. (http://crbug.com/629843)
+  }
+
+  const base::FilePath& file_path() const { return file_path_; }
+
+ private:
+  base::FilePath file_path_;
+};
+
+base::Optional<ScopedTempFile> SavePdf(base::ScopedFD fd) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
+
+  ScopedTempFile temp_file;
+  base::File out(temp_file.file_path(),
+                 base::File::FLAG_CREATE_ALWAYS | base::File::FLAG_WRITE);

[dcheng, 2016/07/25 06:36:30]

Btw, can we just use base::File::FLAG_DELETE_ON_CLOSE here and get rid of the
need for ScopedTempFile? Then we can just return a base::File and use IsValid()
to check for success, right?

[Sergey Poromov, 2016/07/25 13:04:11]

Looks like it's not yet possible to delete on close, as the file needs to be
reopened while opening a tab. There is a TODO few lines before. Especially as
this is a first temporary solution that won't be released to public - it's just
first step to more complex full printing support, that includes much more
interactions with printing stack.

+
+  char buf[8192];
+  ssize_t bytes;
+  while ((bytes = HANDLE_EINTR(read(fd.get(), buf, sizeof(buf)))) > 0) {
+    int written = out.WriteAtCurrentPos(buf, bytes);
+    if (written < 0) {
+      LOG(ERROR) << "Error while saving PDF to a disk";
+      return base::nullopt;
+    }
+  }
+
+  return base::make_optional(temp_file);
+}
+
+void OpenPdf(base::Optional<ScopedTempFile> file) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  if (!file)
+    return;
+
+  GURL gurl = net::FilePathToFileURL(file.value().file_path());
+  ash::WmShell::Get()->delegate()->OpenUrl(gurl);
+}
+
+}  // namespace
+
+namespace arc {
+
+ArcPrintService::ArcPrintService(ArcBridgeService* bridge_service)
+    : ArcService(bridge_service), binding_(this) {
+  arc_bridge_service()->print()->AddObserver(this);
+}
+
+ArcPrintService::~ArcPrintService() {
+  arc_bridge_service()->print()->RemoveObserver(this);
+}
+
+void ArcPrintService::OnInstanceReady() {
+  mojom::PrintInstance* print_instance =
+      arc_bridge_service()->print()->instance();
+  if (!print_instance) {
+    LOG(ERROR) << "OnPrintInstanceReady called, but no print instance found";
+    return;
+  }
+
+  print_instance->Init(binding_.CreateInterfacePtrAndBind());
+}
+
+void ArcPrintService::Print(mojo::ScopedHandle file) {
+  if (!file.is_valid()) {
+    LOG(ERROR) << "handle is invalid";
+    return;
+  }
+
+  mojo::edk::ScopedPlatformHandle scoped_platform_handle;
+  MojoResult mojo_result = mojo::edk::PassWrappedPlatformHandle(
+      file.release().value(), &scoped_platform_handle);
+  if (mojo_result != MOJO_RESULT_OK) {
+    LOG(ERROR) << "PassWrappedPlatformHandle failed: " << mojo_result;
+    return;
+  }
+
+  base::ScopedFD fd(scoped_platform_handle.release().handle);
+
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::FILE, FROM_HERE,
+      base::Bind(&SavePdf, base::Passed(&fd)), base::Bind(&OpenPdf));
+}
+
+}  // namespace arc