Initial RemoteCommandService

components/policy/core/common/remote_commands/remote_commands_service.cc

Index: components/policy/core/common/remote_commands/remote_commands_service.cc
diff --git a/components/policy/core/common/remote_commands/remote_commands_service.cc b/components/policy/core/common/remote_commands/remote_commands_service.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e9dca647e9b127b3d30518bdb69179decc4ca637
--- /dev/null
+++ b/components/policy/core/common/remote_commands/remote_commands_service.cc
@@ -0,0 +1,148 @@
+// Copyright 2015 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/policy/core/common/remote_commands/remote_commands_service.h"
+
+#include <algorithm>
+#include <string>
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/time/clock.h"
+#include "base/time/time.h"
+#include "components/policy/core/common/cloud/cloud_policy_client.h"
+#include "components/policy/core/common/remote_commands/remote_commands_factory.h"
+
+namespace policy {
+
+namespace em = enterprise_management;
+
+RemoteCommandsService::RemoteCommandsService(
+    scoped_ptr<RemoteCommandsFactory> factory,
+    CloudPolicyClient* client)
+    : factory_(factory.Pass()), client_(client), weak_factory_(this) {
+  queue_.AddObserver(this);
+}
+
+RemoteCommandsService::~RemoteCommandsService() {
+  queue_.RemoveObserver(this);
+}
+
+bool RemoteCommandsService::FetchRemoteCommands() {
+  if (command_fetch_in_progress_) {
+    has_enqueued_fetch_request_ = true;
+    return false;
+  }
+
+  command_fetch_in_progress_ = true;
+  has_enqueued_fetch_request_ = false;
+
+  std::vector<em::RemoteCommandResult> previous_results;
+  unsent_results_.swap(previous_results);
+
+  scoped_ptr<RemoteCommandJob::UniqueIDType> id_to_acknowlede = nullptr;

[bartfab (slow), 2015/03/12 14:00:55]

Nit 1: s/acknowlede/acknowledge/
Nit 2: The constructor automatically initializes this to a nullptr.

[binjin, 2015/03/12 17:58:58]

Done.

+
+  if (has_last_executed_command_id_) {
+    // Acknowledges |last_executed_command_id_|, and removes it and every
+    // commands before it from |fetched_command_ids_|.

[bartfab (slow), 2015/03/12 14:00:55]

Nit: s/commands/command/

[binjin, 2015/03/12 17:58:57]

Done.

+    id_to_acknowlede.reset(
+        new RemoteCommandJob::UniqueIDType(last_executed_command_id_));
+    while (!fetched_command_ids_.empty() &&
+           fetched_command_ids_.front() != last_executed_command_id_) {
+      fetched_command_ids_.pop_front();
+    }

[bartfab (slow), 2015/03/12 14:00:55]

What if there is a fetch in progress right now? Since that fetch started in the
past, it will contain commands that we just acknowledged. But you already
removed these from |fetched_command_ids_|, so we will not realize this and add
them back to the queue.

[binjin, 2015/03/12 17:58:58]

This piece of code is used to prepare another fetch request and there should be
no other fetch ongoing.

+  }
+
+  client_->FetchRemoteCommands(
+      id_to_acknowlede.Pass(), previous_results,
+      base::Bind(&RemoteCommandsService::OnRemoteCommandsFetched,
+                 weak_factory_.GetWeakPtr()));
+
+  return true;
+}
+
+void RemoteCommandsService::SetClockForTesting(scoped_ptr<base::Clock> clock) {
+  queue_.SetClockForTesting(clock.Pass());
+}
+
+void RemoteCommandsService::EnqueueCommand(
+    const enterprise_management::RemoteCommand& command) {
+  if (!command.has_type() || !command.has_unique_id()) {
+    LOG(WARNING) << "Invalid remote command from server.";
+    return;
+  }
+
+  // If the command is already fetched, ignore it.
+  if (std::find(fetched_command_ids_.begin(), fetched_command_ids_.end(),

[bartfab (slow), 2015/03/12 14:00:55]

You do not actually need to keep a queue and search through it. Since the server
will *always* send commands in order, you can simply keep track of the single
last-fetched command ID. When you get a new list of commands from the server,
look through it linearly once:
- If you find your last-fetched ID in the list, add all commands that follow to
your queue.
- If you do not find your last-fetched ID in the list, add all commands to your
queue.
Then, update the last-fetched ID.

[binjin, 2015/03/12 17:58:58]

As discussed offline, using a queue here will protect us in the case that server
is behaving badly.

+                command.unique_id()) != fetched_command_ids_.end()) {
+    return;
+  }
+
+  fetched_command_ids_.push_back(command.unique_id());
+
+  scoped_ptr<RemoteCommandJob> job = factory_->BuildJobForType(command.type());
+
+  if (!job || !job->Init(command)) {
+    em::RemoteCommandResult ignored_result;
+    ignored_result.set_result(
+        em::RemoteCommandResult_ResultType_RESULT_IGNORED);
+    ignored_result.set_unique_id(command.unique_id());
+    unsent_results_.push_back(ignored_result);
+    return;
+  }
+
+  queue_.AddJob(job.Pass());
+}
+
+void RemoteCommandsService::OnJobStarted(RemoteCommandJob* command) {
+  has_last_executed_command_id_ = true;
+  last_executed_command_id_ = command->unique_id();
+  // TODO(binjin): Attempt to sync |last_executed_command_id_| to some
+  // persistent source, so that we can reload it later without relying solely on
+  // the server to keep our last acknowledged command ID.
+  // See http://crbug.com/466572.
+}
+
+void RemoteCommandsService::OnJobFinished(RemoteCommandJob* command) {
+  em::RemoteCommandResult result;
+  result.set_unique_id(command->unique_id());
+  result.set_timestamp((command->execution_started_time() -
+                        base::Time::UnixEpoch()).InMilliseconds());
+
+  if (command->status() == RemoteCommandJob::SUCCEEDED) {
+    result.set_result(em::RemoteCommandResult_ResultType_RESULT_SUCCESS);
+    const scoped_ptr<std::string> result_payload = command->GetResultPayload();
+    if (result_payload)
+      result.set_payload(*result_payload);
+  } else if (command->status() == RemoteCommandJob::EXPIRED ||
+             command->status() == RemoteCommandJob::INVALID) {
+    result.set_result(em::RemoteCommandResult_ResultType_RESULT_IGNORED);
+  } else {
+    result.set_result(em::RemoteCommandResult_ResultType_RESULT_FAILURE);
+  }
+
+  unsent_results_.push_back(result);
+
+  FetchRemoteCommands();
+}
+
+void RemoteCommandsService::OnRemoteCommandsFetched(
+    DeviceManagementStatus status,
+    const std::vector<enterprise_management::RemoteCommand>& commands) {
+  DCHECK(command_fetch_in_progress_);
+  command_fetch_in_progress_ = false;
+
+  // TODO(binjin): Add retrying on errors. See http://crbug.com/466572.
+  if (status == DM_STATUS_SUCCESS) {
+    for (const auto& command : commands)
+      EnqueueCommand(command);
+  }
+
+  // Start another fetch request job immediately if there are unsent command
+  // results or enqueued fetch requests.
+  if (!unsent_results_.empty() || has_enqueued_fetch_request_)
+    FetchRemoteCommands();
+}
+
+}  // namespace policy