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) {

[dcheng, 2016/07/27 16:43:36]

It doesn't seem like there's any need for ScopedTempFile atm, so let's simplify
this and just return a File object. It's easy enough to add the scoper once
we've figured out the semantics we want.

[Sergey Poromov, 2016/07/27 18:24:41]

lhchavez@ suggested it to avoid trashing /tmp after printing. Unfortunately as
there is yet no way to pass the object further, we couldn't delete it in
destructor. However, the needed API will be build in the next change and TODO
will be fixed.
I prefer not to change it back to temporary get rid of the class.

[dcheng, 2016/07/28 01:38:09]

It's not built out, and there's no obvious need for this abstraction. When we
figure out how we're going to use the created file, that seems like the right
time to figure out what abstraction we need.

There's already a bunch of ScopedTempFiles lying around chromium source, and I
don't really see the need for a third (and not yet implemented) one.

[Sergey Poromov, 2016/07/28 14:43:00]

Done.

+  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);
+
+  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 pdf_data) {
+  if (!pdf_data.is_valid()) {
+    LOG(ERROR) << "handle is invalid";
+    return;
+  }
+
+  mojo::edk::ScopedPlatformHandle scoped_platform_handle;
+  MojoResult mojo_result = mojo::edk::PassWrappedPlatformHandle(
+      pdf_data.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);

[dcheng, 2016/07/27 16:43:36]

I would suggest just creating a base::File from the FD directly rather than
wrapping it in a ScopedFD. Then you can use things like ReadAtCurrentPos(),
which will make the code look a little nicer. In general, it's pretty rare to
see raw read() / write() calls, so I think it will be a bit more consistent with
the rest of Chromium as well.

[Sergey Poromov, 2016/07/27 18:24:41]

Done.

+
+  content::BrowserThread::PostTaskAndReplyWithResult(
+      content::BrowserThread::FILE, FROM_HERE,
+      base::Bind(&SavePdf, base::Passed(&fd)), base::Bind(&OpenPdf));
+}
+
+}  // namespace arc