// Copyright (c) 2011 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 "content/browser/browser_child_process_host.h"

#include "base/command_line.h"
#include "base/file_path.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/path_service.h"
#include "base/process_util.h"
#include "base/stl_util.h"
#include "base/string_util.h"
#include "content/browser/browser_thread.h"
#include "content/browser/content_browser_client.h"
#include "content/browser/renderer_host/resource_message_filter.h"
#include "content/browser/trace_message_filter.h"
#include "content/common/content_switches.h"
#include "content/common/notification_service.h"
#include "content/common/plugin_messages.h"
#include "content/common/process_watcher.h"
#include "content/common/result_codes.h"

namespace {

typedef std::list<BrowserChildProcessHost*> ChildProcessList;
static base::LazyInstance<ChildProcessList> g_child_process_list(
    base::LINKER_INITIALIZED);

// The NotificationTask is used to notify about plugin process connection/
// disconnection. It is needed because the notifications in the
// NotificationService must happen in the main thread.
class ChildNotificationTask : public Task {
 public:
  ChildNotificationTask(
      int notification_type, ChildProcessInfo* info)
      : notification_type_(notification_type), info_(*info) { }

  virtual void Run() {
    NotificationService::current()->
        Notify(notification_type_, NotificationService::AllSources(),
               Details<ChildProcessInfo>(&info_));
  }

 private:
  int notification_type_;
  ChildProcessInfo info_;
};

}  // namespace

BrowserChildProcessHost::BrowserChildProcessHost(
    ChildProcessInfo::ProcessType type)
    : ChildProcessInfo(type, -1),
      ALLOW_THIS_IN_INITIALIZER_LIST(client_(this)) {
  AddFilter(new TraceMessageFilter);

  g_child_process_list.Get().push_back(this);
}

BrowserChildProcessHost::~BrowserChildProcessHost() {
  g_child_process_list.Get().remove(this);
}

// static
void BrowserChildProcessHost::TerminateAll() {
  // Make a copy since the ChildProcessHost dtor mutates the original list.
  ChildProcessList copy = g_child_process_list.Get();
  STLDeleteElements(&copy);
}

void BrowserChildProcessHost::Launch(
#if defined(OS_WIN)
    const FilePath& exposed_dir,
#elif defined(OS_POSIX)
    bool use_zygote,
    const base::environment_vector& environ,
#endif
    CommandLine* cmd_line) {

  content::GetContentClient()->browser()->AppendExtraCommandLineSwitches(
      cmd_line, id());

  child_process_.reset(new ChildProcessLauncher(
#if defined(OS_WIN)
      exposed_dir,
#elif defined(OS_POSIX)
      use_zygote,
      environ,
      channel()->GetClientFileDescriptor(),
#endif
      cmd_line,
      &client_));
}

base::ProcessHandle BrowserChildProcessHost::GetChildProcessHandle() const {
  DCHECK(child_process_.get())
      << "Requesting a child process handle before launching.";
  DCHECK(child_process_->GetHandle())
      << "Requesting a child process handle before launch has completed OK.";
  return child_process_->GetHandle();
}

void BrowserChildProcessHost::ForceShutdown() {
  g_child_process_list.Get().remove(this);
  ChildProcessHost::ForceShutdown();
}

void BrowserChildProcessHost::SetTerminateChildOnShutdown(
  bool terminate_on_shutdown) {
  child_process_->SetTerminateChildOnShutdown(terminate_on_shutdown);
}

void BrowserChildProcessHost::Notify(int type) {
  BrowserThread::PostTask(
      BrowserThread::UI, FROM_HERE, new ChildNotificationTask(type, this));
}

base::TerminationStatus BrowserChildProcessHost::GetChildTerminationStatus(
    int* exit_code) {
  return child_process_->GetChildTerminationStatus(exit_code);
}

void BrowserChildProcessHost::OnChildDied() {
  // This may be called by both the channel's OnChannelError handler
  // as well as the process launcher's OnProcessLaunched handler.
  if (handle() != base::kNullProcessHandle) {
    int exit_code;
    base::TerminationStatus status = GetChildTerminationStatus(&exit_code);
    switch (status) {
      case base::TERMINATION_STATUS_PROCESS_CRASHED:
      case base::TERMINATION_STATUS_ABNORMAL_TERMINATION: {
        OnProcessCrashed(exit_code);

        // Report that this child process crashed.
        Notify(content::NOTIFICATION_CHILD_PROCESS_CRASHED);
        UMA_HISTOGRAM_COUNTS("ChildProcess.Crashes", this->type());
        break;
      }
      case base::TERMINATION_STATUS_PROCESS_WAS_KILLED: {
        OnProcessWasKilled(exit_code);

        // Report that this child process was killed.
        Notify(content::NOTIFICATION_CHILD_PROCESS_WAS_KILLED);
        UMA_HISTOGRAM_COUNTS("ChildProcess.Kills", this->type());
        break;
      }
      default:
        break;
    }
    // Notify in the main loop of the disconnection.
    Notify(content::NOTIFICATION_CHILD_PROCESS_HOST_DISCONNECTED);
  }
  ChildProcessHost::OnChildDied();
}

void BrowserChildProcessHost::ShutdownStarted() {
  // Must remove the process from the list now, in case it gets used for a
  // new instance before our watcher tells us that the process terminated.
  g_child_process_list.Get().remove(this);
}

BrowserChildProcessHost::ClientHook::ClientHook(BrowserChildProcessHost* host)
    : host_(host) {
}

void BrowserChildProcessHost::ClientHook::OnProcessLaunched() {
  if (!host_->child_process_->GetHandle()) {
    host_->OnChildDied();
    return;
  }
  host_->set_handle(host_->child_process_->GetHandle());
  host_->OnProcessLaunched();
}

BrowserChildProcessHost::Iterator::Iterator()
    : all_(true), type_(UNKNOWN_PROCESS) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO)) <<
          "ChildProcessInfo::Iterator must be used on the IO thread.";
  iterator_ = g_child_process_list.Get().begin();
}

BrowserChildProcessHost::Iterator::Iterator(ChildProcessInfo::ProcessType type)
    : all_(false), type_(type) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO)) <<
          "ChildProcessInfo::Iterator must be used on the IO thread.";
  iterator_ = g_child_process_list.Get().begin();
  if (!Done() && (*iterator_)->type() != type_)
    ++(*this);
}

BrowserChildProcessHost* BrowserChildProcessHost::Iterator::operator++() {
  do {
    ++iterator_;
    if (Done())
      break;

    if (!all_ && (*iterator_)->type() != type_)
      continue;

    return *iterator_;
  } while (true);

  return NULL;
}

bool BrowserChildProcessHost::Iterator::Done() {
  return iterator_ == g_child_process_list.Get().end();
}