Download driver for components/download.

components/download/content/download_driver_impl.cc

+// Copyright 2017 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 "components/download/content/download_driver_impl.h"
+
+#include "base/files/file_path.h"
+#include "content/public/browser/download_interrupt_reasons.h"
+#include "content/public/browser/download_url_parameters.h"
+#include "content/public/browser/storage_partition.h"
+
+namespace download {
+
+DownloadDriverImpl::DownloadDriverImpl(content::DownloadManager* manager)
+    : download_manager_(manager), observer_(nullptr) {
+  DCHECK(download_manager_);
+  download_manager_->AddObserver(this);
+}
+
+DownloadDriverImpl::~DownloadDriverImpl() = default;
+
+void DownloadDriverImpl::Start(const DownloadParams& params) {
+  DCHECK(!params.request_params.url.is_empty());
+  DCHECK(!params.guid.empty());
+
+  content::StoragePartition* storage_partition =
+      content::BrowserContext::GetStoragePartitionForSite(
+          download_manager_->GetBrowserContext(), params.request_params.url);
+  DCHECK(storage_partition);
+
+  std::unique_ptr<content::DownloadUrlParameters> download_url_params(
+      new content::DownloadUrlParameters(
+          params.request_params.url,
+          storage_partition->GetURLRequestContext()));
+
+  // TODO(xingliu): Handles the request headers from |params|, needs to tweak

[David Trainor- moved to gerrit, 2017/05/15 20:08:14]

Handles -> Handle, needs -> need  Passes -> Pass

[xingliu, 2017/05/17 19:34:52]

Done.

+  // download network stack. Passes the file path and file name.

[David Trainor- moved to gerrit, 2017/05/15 20:08:14]

We should make the file name the guid or something.

[xingliu, 2017/05/17 19:34:52]

Done.

+  download_url_params->set_guid(params.guid);
+  download_url_params->set_transient(true);
+  download_url_params->set_method(params.request_params.method);
+
+  download_manager_->DownloadUrl(std::move(download_url_params));
+}
+
+void DownloadDriverImpl::Cancel(const std::string& guid) {
+  content::DownloadItem* item = download_manager_->GetDownloadByGuid(guid);
+  // Cancels the download and removes the persisted records in content layer.
+  if (item) {
+    item->RemoveObserver(this);
+    item->Remove();
+  }
+}
+
+void DownloadDriverImpl::Pause(const std::string& guid) {
+  content::DownloadItem* item = download_manager_->GetDownloadByGuid(guid);
+  if (item)
+    item->Pause();
+}
+
+void DownloadDriverImpl::Resume(const std::string& guid) {
+  content::DownloadItem* item = download_manager_->GetDownloadByGuid(guid);
+  if (item)
+    item->Resume();
+}
+
+bool DownloadDriverImpl::IsReady() const {
+  return download_manager_->IsManagerInitialized();
+}
+
+void DownloadDriverImpl::SetObserver(DownloadDriver::Observer* observer) {
+  observer_ = observer;

[David Trainor- moved to gerrit, 2017/05/15 20:08:14]

Do we need to notify the observer that we're initialized here if the
DownloadManager is already initialized?  I guess we can check IsReady as well,
but it might just add more complexity to the caller.

[xingliu, 2017/05/17 19:34:52]

Done, change to pass a Client* through Initialize call, removed IsReady. Client
will be notified in the Initialize call if DownloadManager is already
initialized.

+}
+
+void DownloadDriverImpl::OnDownloadUpdated(content::DownloadItem* item) {
+  DCHECK(item);
+  if (!observer_)
+    return;
+
+  using DownloadState = content::DownloadItem::DownloadState;
+  DownloadState state = item->GetState();
+  content::DownloadInterruptReason reason = item->GetLastReason();
+
+  if (state == DownloadState::COMPLETE) {
+    observer_->OnDownloadSucceeded(item->GetGuid(), item->GetTargetFilePath(),
+                                   item->GetReceivedBytes());

[David Trainor- moved to gerrit, 2017/05/15 20:08:14]

Remove observer on the item here and/or when it fails?

[xingliu, 2017/05/17 19:34:52]

Done, good catch.

+  } else if (state == DownloadState::IN_PROGRESS) {
+    observer_->OnDownloadUpdated(item->GetGuid(), item->GetReceivedBytes());

[David Trainor- moved to gerrit, 2017/05/15 20:08:14]

We'll need estimated progress as well.  Would it just make sense to have a
DriverEntryState struct that has things like:

guid
state (not started, progress, paused, complete, cancelled, failed, etc.)
percent completed
bytes received
request headers
request response code?
etc?

[xingliu, 2017/05/17 19:34:52]

Done.

+  } else if (reason !=
+             content::DownloadInterruptReason::DOWNLOAD_INTERRUPT_REASON_NONE) {

[David Trainor- moved to gerrit, 2017/05/15 20:08:14]

We probably need all of the paused/resumed information as well so we can track
other in-progress downloads.  See state suggestion above.

[xingliu, 2017/05/17 19:34:52]

Done. added the is_paused, if we need more thing we can add later.

+    observer_->OnDownloadFailed(item->GetGuid(), static_cast<int>(reason));
+  }
+}
+
+void DownloadDriverImpl::OnDownloadCreated(content::DownloadManager* manager,
+                                           content::DownloadItem* item) {
+  // Listens to all downloads.
+  item->AddObserver(this);
+
+  // TODO(xingliu): Pumps the response headers if needed from download network
+  // stack.
+  if (observer_)
+    observer_->OnDownloadCreated(item->GetGuid());
+}
+
+void DownloadDriverImpl::OnManagerInitialized() {
+  if (observer_)
+    observer_->OnDriverReady();
+}
+
+void DownloadDriverImpl::ManagerGoingDown(content::DownloadManager* manager) {
+  manager->RemoveObserver(this);
+}
+
+}  // namespace download