// Copyright (c) 2009 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/worker_host/worker_service.h"

#include "base/command_line.h"
#include "base/singleton.h"
#include "base/sys_info.h"
#include "base/thread.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/plugin_service.h"
#include "chrome/browser/renderer_host/render_process_host.h"
#include "chrome/browser/renderer_host/resource_message_filter.h"
#include "chrome/browser/worker_host/worker_process_host.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/notification_service.h"
#include "chrome/common/worker_messages.h"
#include "net/base/registry_controlled_domain.h"

const int WorkerService::kMaxWorkerProcessesWhenSharing = 10;
const int WorkerService::kMaxWorkersWhenSeparate = 64;
const int WorkerService::kMaxWorkersPerTabWhenSeparate = 16;

WorkerService* WorkerService::GetInstance() {
  return Singleton<WorkerService>::get();
}

WorkerService::WorkerService()
    : next_worker_route_id_(0),
      resource_dispatcher_host_(NULL),
      ui_loop_(NULL) {
  // Receive a notification if a message filter or WorkerProcessHost is deleted.
  registrar_.Add(this, NotificationType::RESOURCE_MESSAGE_FILTER_SHUTDOWN,
                 NotificationService::AllSources());

  registrar_.Add(this, NotificationType::WORKER_PROCESS_HOST_SHUTDOWN,
                 NotificationService::AllSources());
}

void WorkerService::Initialize(ResourceDispatcherHost* rdh,
                               MessageLoop* ui_loop) {
  resource_dispatcher_host_ = rdh;
  ui_loop_ = ui_loop;
}

WorkerService::~WorkerService() {
}

bool WorkerService::CreateDedicatedWorker(const GURL &url,
                                          int renderer_id,
                                          int render_view_route_id,
                                          IPC::Message::Sender* sender,
                                          int sender_id,
                                          int sender_route_id) {
  // Generate a unique route id for the browser-worker communication that's
  // unique among all worker processes.  That way when the worker process sends
  // a wrapped IPC message through us, we know which WorkerProcessHost to give
  // it to.
  WorkerProcessHost::WorkerInstance instance;
  instance.url = url;
  instance.renderer_id = renderer_id;
  instance.render_view_route_id = render_view_route_id;
  instance.worker_route_id = next_worker_route_id();
  instance.sender = sender;
  instance.sender_id = sender_id;
  instance.sender_route_id = sender_route_id;

  WorkerProcessHost* worker = NULL;
  if (CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kWebWorkerProcessPerCore)) {
    worker = GetProcessToFillUpCores();
  } else if (CommandLine::ForCurrentProcess()->HasSwitch(
                 switches::kWebWorkerShareProcesses)) {
    worker = GetProcessForDomain(url);
  } else {  // One process per worker.
    if (!CanCreateWorkerProcess(instance)) {
      queued_workers_.push_back(instance);
      return true;
    }
  }

  if (!worker) {
    worker = new WorkerProcessHost(resource_dispatcher_host_);
    if (!worker->Init()) {
      delete worker;
      return false;
    }
  }

  worker->CreateWorker(instance);
  return true;
}

void WorkerService::CancelCreateDedicatedWorker(int sender_id,
                                                int sender_route_id) {
  for (WorkerProcessHost::Instances::iterator i = queued_workers_.begin();
       i != queued_workers_.end(); ++i) {
     if (i->sender_id == sender_id &&
         i->sender_route_id == sender_route_id) {
       queued_workers_.erase(i);
       return;
     }
  }

  // There could be a race condition where the WebWorkerProxy told us to cancel
  // the worker right as we sent it a message say it's been created.  Look at
  // the running workers.
  for (ChildProcessHost::Iterator iter(ChildProcessInfo::WORKER_PROCESS);
       !iter.Done(); ++iter) {
    WorkerProcessHost* worker = static_cast<WorkerProcessHost*>(*iter);
    for (WorkerProcessHost::Instances::const_iterator instance =
             worker->instances().begin();
         instance != worker->instances().end(); ++instance) {
      if (instance->sender_id == sender_id &&
          instance->sender_route_id == sender_route_id) {
        // Fake a worker destroyed message so that WorkerProcessHost cleans up
        // properly.
        WorkerHostMsg_WorkerContextDestroyed msg(sender_route_id);
        ForwardMessage(msg, sender_id);
        return;
      }
    }
  }

  DCHECK(false) << "Couldn't find worker to cancel";
}

void WorkerService::ForwardMessage(const IPC::Message& message,
                                   int sender_pid) {
  for (ChildProcessHost::Iterator iter(ChildProcessInfo::WORKER_PROCESS);
       !iter.Done(); ++iter) {
    WorkerProcessHost* worker = static_cast<WorkerProcessHost*>(*iter);
    if (worker->FilterMessage(message, sender_pid))
      return;
  }

  // TODO(jabdelmalek): tell sender that callee is gone
}

WorkerProcessHost* WorkerService::GetProcessForDomain(const GURL& url) {
  int num_processes = 0;
  std::string domain =
      net::RegistryControlledDomainService::GetDomainAndRegistry(url);
  for (ChildProcessHost::Iterator iter(ChildProcessInfo::WORKER_PROCESS);
       !iter.Done(); ++iter) {
    num_processes++;
    WorkerProcessHost* worker = static_cast<WorkerProcessHost*>(*iter);
    for (WorkerProcessHost::Instances::const_iterator instance =
             worker->instances().begin();
         instance != worker->instances().end(); ++instance) {
      if (net::RegistryControlledDomainService::GetDomainAndRegistry(
          instance->url) == domain) {
        return worker;
      }
    }
  }

  if (num_processes >= kMaxWorkerProcessesWhenSharing)
    return GetLeastLoadedWorker();

  return NULL;
}

WorkerProcessHost* WorkerService::GetProcessToFillUpCores() {
  int num_processes = 0;
  ChildProcessHost::Iterator iter(ChildProcessInfo::WORKER_PROCESS);
  for (; !iter.Done(); ++iter)
    num_processes++;

  if (num_processes >= base::SysInfo::NumberOfProcessors())
    return GetLeastLoadedWorker();

  return NULL;
}

WorkerProcessHost* WorkerService::GetLeastLoadedWorker() {
  WorkerProcessHost* smallest = NULL;
  for (ChildProcessHost::Iterator iter(ChildProcessInfo::WORKER_PROCESS);
       !iter.Done(); ++iter) {
    WorkerProcessHost* worker = static_cast<WorkerProcessHost*>(*iter);
    if (!smallest || worker->instances().size() < smallest->instances().size())
      smallest = worker;
  }

  return smallest;
}

bool WorkerService::CanCreateWorkerProcess(
    const WorkerProcessHost::WorkerInstance& instance) {
  int total_workers = 0;
  int workers_per_tab = 0;
  for (ChildProcessHost::Iterator iter(ChildProcessInfo::WORKER_PROCESS);
       !iter.Done(); ++iter) {
    WorkerProcessHost* worker = static_cast<WorkerProcessHost*>(*iter);
    for (WorkerProcessHost::Instances::const_iterator cur_instance =
             worker->instances().begin();
         cur_instance != worker->instances().end(); ++cur_instance) {
      total_workers++;
      if (total_workers >= kMaxWorkersWhenSeparate)
        return false;
      if (cur_instance->renderer_id == instance.renderer_id &&
          cur_instance->render_view_route_id == instance.render_view_route_id) {
        workers_per_tab++;
        if (workers_per_tab >= kMaxWorkersPerTabWhenSeparate)
          return false;
      }
    }
  }

  return true;
}

void WorkerService::Observe(NotificationType type,
                            const NotificationSource& source,
                            const NotificationDetails& details) {
  if (type.value == NotificationType::RESOURCE_MESSAGE_FILTER_SHUTDOWN) {
    ResourceMessageFilter* sender = Source<ResourceMessageFilter>(source).ptr();
    SenderShutdown(sender);
  } else if (type.value == NotificationType::WORKER_PROCESS_HOST_SHUTDOWN) {
    WorkerProcessHost* sender = Source<WorkerProcessHost>(source).ptr();
    SenderShutdown(sender);
    WorkerProcessDestroyed(sender);
  } else {
    NOTREACHED();
  }
}

void WorkerService::SenderShutdown(IPC::Message::Sender* sender) {
  for (ChildProcessHost::Iterator iter(ChildProcessInfo::WORKER_PROCESS);
       !iter.Done(); ++iter) {
    WorkerProcessHost* worker = static_cast<WorkerProcessHost*>(*iter);
    worker->SenderShutdown(sender);
  }

  // See if that render process had any queued workers.
  for (WorkerProcessHost::Instances::iterator i = queued_workers_.begin();
       i != queued_workers_.end();) {
    if (i->sender == sender) {
      i = queued_workers_.erase(i);
    } else {
      ++i;
    }
  }
}

void WorkerService::WorkerProcessDestroyed(WorkerProcessHost* process) {
  if (queued_workers_.empty())
    return;

  for (WorkerProcessHost::Instances::iterator i = queued_workers_.begin();
       i != queued_workers_.end();) {
    if (CanCreateWorkerProcess(*i)) {
      WorkerProcessHost* worker =
          new WorkerProcessHost(resource_dispatcher_host_);
      if (!worker->Init()) {
        delete worker;
        return;
      }

      worker->CreateWorker(*i);
      i = queued_workers_.erase(i);
    } else {
      ++i;
    }
  }
}