Dump property values for the touch log source

chrome/browser/chromeos/system_logs/touch_log_source_ozone.cc

 // Copyright (c) 2013 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/system_logs/touch_log_source.h"
 
 #include "ash/touch/touch_hud_debug.h"
 #include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/callback.h"
 #include "base/command_line.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/logging.h"
+#include "base/message_loop/message_loop.h"
 #include "base/process/launch.h"
 #include "components/feedback/feedback_util.h"
 #include "content/public/browser/browser_thread.h"
+#include "ui/ozone/public/input_controller.h"
+#include "ui/ozone/public/ozone_platform.h"
 
 using content::BrowserThread;
 
 namespace {
 
 const char kHUDLogDataKey[] = "hud_log";
 
-void GetTouchLogsOzone(system_logs::SystemLogsResponse* response) {
+// The prefix "hack-33025" was historically chosen in http://crbug.com/139715.
+// We continue to go with it in order to be compatible with the existing touch
+// log processing toolchain.
+const char kDeviceStatusLogDataKey[] = "hack-33025-touchpad";
+
+// Token string for the sequenced worker pool.
+const char kDefaultSequenceName[] = "TouchLogWriter";
+
+scoped_refptr<base::SequencedTaskRunner> GetSequencedTaskRunner(
+    const std::string sequence_name) {
+  base::SequencedWorkerPool* pool = content::BrowserThread::GetBlockingPool();
+  return pool->GetSequencedTaskRunnerWithShutdownBehavior(
+      pool->GetNamedSequenceToken(sequence_name),
+      base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
+}
+
+// Callback for handing the outcome of CollectStatusLog(). Appends the
+// collected log to the SystemLogsResponse map.
+void OnStatusLogCollected(system_logs::SystemLogsResponse* response,
+                          const system_logs::SysLogsSourceCallback& callback,
+                          std::string* log) {
+  (*response)[kDeviceStatusLogDataKey] = *log;
+
+  GetSequencedTaskRunner(kDefaultSequenceName)
+      ->PostTask(FROM_HERE, base::Bind(callback, base::Owned(response)));
+}
+
+// Collect touch device status logs (containing property values).
+void CollectStatusLog(system_logs::SystemLogsResponse* response,
+                      const system_logs::SysLogsSourceCallback& callback) {
+  ui::OzonePlatform::GetInstance()->GetInputController()->GetTouchDeviceStatus(
+      base::Bind(&OnStatusLogCollected, response, callback));
+}
+
+// Entry point for the touch log collection tasks.
+void StartLogRetrieval(system_logs::SystemLogsResponse* response,
+                       const system_logs::SysLogsSourceCallback& callback) {
+  // Collect touch HUD logs.
   scoped_ptr<base::DictionaryValue> dictionary =
       ash::TouchHudDebug::GetAllAsDictionary();

[spang, 2015/01/27 20:15:13]

This seems scary.. what makes it safe to call ash from the blocking pool?

[spang, 2015/01/27 20:44:56]

Can you do this part on UI and pass the results along? That would eliminate my
concern.

[Shecky Lin, 2015/01/27 23:08:15]

Done.

   if (!dictionary->empty()) {
     std::string touch_log;
     JSONStringValueSerializer json(&touch_log);
     json.set_pretty_print(true);
     if (json.Serialize(*dictionary) && !touch_log.empty())
       (*response)[kHUDLogDataKey] = touch_log;
   }
 
-  // TODO(sheckylin): Add ozone touch log collection implementation. See
-  // http://crbug.com/400022.
-  NOTIMPLEMENTED();
+  // Collect touch device status logs.
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&CollectStatusLog, response, callback));

[spang, 2015/01/27 20:15:12]

Do you need this task hop? Aren't we already on UI?

If so you can inline CollectStatusLog() here.

[spang, 2015/01/27 20:42:37]

My bad, I misread the code, TouchLogSource::Fetch is the UI part. This is right.

[Shecky Lin, 2015/01/27 23:08:15]

Done.

 }
 
 }  // namespace
 
 namespace system_logs {
 
 void TouchLogSource::Fetch(const SysLogsSourceCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
 
   SystemLogsResponse* response = new SystemLogsResponse;
-  BrowserThread::PostBlockingPoolTaskAndReply(
-      FROM_HERE, base::Bind(&GetTouchLogsOzone, response),
-      base::Bind(callback, base::Owned(response)));
+  GetSequencedTaskRunner(kDefaultSequenceName)
+      ->PostTask(FROM_HERE, base::Bind(&StartLogRetrieval, response, callback));

[spang, 2015/01/27 20:15:13]

Use base::Passed() to pass ownership of response through the callback. This
makes the code a lot clearer and also prevents memory leaks if PostTask fails
and the the callback never executes.

[Shecky Lin, 2015/01/27 23:08:15]

Done.

 }
 
 }  // namespace system_logs