// 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/appcache/chrome_appcache_service.h"

#include "base/file_path.h"
#include "base/file_util.h"
#include "content/browser/content_browser_client.h"
#include "content/common/notification_service.h"
#include "net/base/net_errors.h"
#include "webkit/appcache/appcache_thread.h"
#include "webkit/quota/quota_manager.h"

static bool has_initialized_thread_ids;

namespace {

// Used to defer deleting of local storage until the destructor has finished.
void DeleteLocalStateOnIOThread(FilePath cache_path) {
  // Post the actual deletion to the DB thread to ensure it happens after the
  // database file has been closed.
  BrowserThread::PostTask(
      BrowserThread::DB, FROM_HERE,
      NewRunnableFunction<bool(*)(const FilePath&, bool), FilePath, bool>(
          &file_util::Delete, cache_path, true));
}

}  // namespace

// ----------------------------------------------------------------------------

ChromeAppCacheService::ChromeAppCacheService(
    quota::QuotaManagerProxy* quota_manager_proxy)
    : AppCacheService(quota_manager_proxy),
      resource_context_(NULL), clear_local_state_on_exit_(false) {
}

void ChromeAppCacheService::InitializeOnIOThread(
    const FilePath& cache_path,
    const content::ResourceContext* resource_context,
    scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy,
    bool clear_local_state_on_exit) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));

  if (!has_initialized_thread_ids) {
    has_initialized_thread_ids = true;
    appcache::AppCacheThread::Init(BrowserThread::DB, BrowserThread::IO);
  }

  cache_path_ = cache_path;
  resource_context_ = resource_context;
  registrar_.Add(
      this, content::NOTIFICATION_PURGE_MEMORY,
      NotificationService::AllSources());
  SetClearLocalStateOnExit(clear_local_state_on_exit);

  // Init our base class.
  Initialize(cache_path_,
             BrowserThread::GetMessageLoopProxyForThread(BrowserThread::CACHE));
  set_appcache_policy(this);
  set_special_storage_policy(special_storage_policy);
}

ChromeAppCacheService::~ChromeAppCacheService() {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));

  if (clear_local_state_on_exit_ && !cache_path_.empty()) {
    BrowserThread::PostTask(
        BrowserThread::IO, FROM_HERE,
        NewRunnableFunction(DeleteLocalStateOnIOThread, cache_path_));
  }
}

void ChromeAppCacheService::SetClearLocalStateOnExit(bool clear_local_state) {
  // TODO(michaeln): How is 'protected' status granted to apps in this case?
  if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
    BrowserThread::PostTask(
        BrowserThread::IO, FROM_HERE,
        NewRunnableMethod(this,
                          &ChromeAppCacheService::SetClearLocalStateOnExit,
                          clear_local_state));
    return;
  }
  clear_local_state_on_exit_ = clear_local_state;
}

bool ChromeAppCacheService::CanLoadAppCache(const GURL& manifest_url) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  // We don't prompt for read access.
  return content::GetContentClient()->browser()->AllowAppCache(
      manifest_url, *resource_context_);
}

int ChromeAppCacheService::CanCreateAppCache(
    const GURL& manifest_url, net::CompletionCallback* callback) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  return content::GetContentClient()->browser()->AllowAppCache(
      manifest_url, *resource_context_) ? net::OK : net::ERR_ACCESS_DENIED;
}

void ChromeAppCacheService::Observe(int type,
                                    const NotificationSource& source,
                                    const NotificationDetails& details) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  DCHECK(type == content::NOTIFICATION_PURGE_MEMORY);
  PurgeMemory();
}

// ----------------------------------------------------------------------------

static BrowserThread::ID ToBrowserThreadID(int id) {
  DCHECK(has_initialized_thread_ids);
  DCHECK(id == BrowserThread::DB || id == BrowserThread::IO);
  return static_cast<BrowserThread::ID>(id);
}

namespace appcache {

// An impl of AppCacheThread we need to provide to the appcache lib.

bool AppCacheThread::PostTask(
    int id,
    const tracked_objects::Location& from_here,
    Task* task) {
  return BrowserThread::PostTask(ToBrowserThreadID(id), from_here, task);
}

bool AppCacheThread::CurrentlyOn(int id) {
  return BrowserThread::CurrentlyOn(ToBrowserThreadID(id));
}

}  // namespace appcache