web_application_cache_host_impl.cc

// Copyright (c) 2010 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 "webkit/appcache/web_application_cache_host_impl.h"

#include "base/compiler_specific.h"
#include "base/id_map.h"
#include "base/lazy_instance.h"
#include "base/string_util.h"
#include "base/stringprintf.h"
#include "third_party/WebKit/WebKit/chromium/public/WebDataSource.h"
#include "third_party/WebKit/WebKit/chromium/public/WebFrame.h"
#include "third_party/WebKit/WebKit/chromium/public/WebURL.h"
#include "third_party/WebKit/WebKit/chromium/public/WebURLRequest.h"
#include "third_party/WebKit/WebKit/chromium/public/WebURLResponse.h"

using WebKit::WebApplicationCacheHost;
using WebKit::WebApplicationCacheHostClient;
using WebKit::WebDataSource;
using WebKit::WebFrame;
using WebKit::WebURLRequest;
using WebKit::WebURL;
using WebKit::WebURLResponse;
using WebKit::WebVector;

namespace appcache {

namespace {

typedef IDMap<WebApplicationCacheHostImpl> HostsMap;
static base::LazyInstance<HostsMap> g_hosts_map(base::LINKER_INITIALIZED);

// Note: the order of the elements in this array must match those
// of the EventID enum in appcache_interfaces.h.
const char* kEventNames[] = {
  "Checking", "Error", "NoUpdate", "Downloading", "Progress",
  "UpdateReady", "Cached", "Obsolete"
};

GURL ClearUrlRef(const GURL& url) {
  if (!url.has_ref())
    return url;
  GURL::Replacements replacements;
  replacements.ClearRef();
  return url.ReplaceComponents(replacements);
}

}  // anon namespace

WebApplicationCacheHostImpl* WebApplicationCacheHostImpl::FromId(int id) {
  return g_hosts_map.Get().Lookup(id);
}

WebApplicationCacheHostImpl* WebApplicationCacheHostImpl::FromFrame(
    WebFrame* frame) {
  if (!frame)
    return NULL;
  WebDataSource* data_source = frame->dataSource();
  if (!data_source)
    return NULL;
  return static_cast<WebApplicationCacheHostImpl*>
      (data_source->applicationCacheHost());
}

WebApplicationCacheHostImpl::WebApplicationCacheHostImpl(
    WebApplicationCacheHostClient* client,
    AppCacheBackend* backend)
    : client_(client),
      backend_(backend),
      ALLOW_THIS_IN_INITIALIZER_LIST(host_id_(g_hosts_map.Get().Add(this))),
      has_status_(false),
      status_(UNCACHED),
      has_cached_status_(false),
      cached_status_(UNCACHED),
      is_scheme_supported_(false),
      is_get_method_(false),
      is_new_master_entry_(MAYBE) {
  DCHECK(client && backend && (host_id_ != kNoHostId));

  backend_->RegisterHost(host_id_);
}

WebApplicationCacheHostImpl::~WebApplicationCacheHostImpl() {
  backend_->UnregisterHost(host_id_);
  g_hosts_map.Get().Remove(host_id_);
}

void WebApplicationCacheHostImpl::OnCacheSelected(
    const appcache::AppCacheInfo& info) {
  status_ = info.status;
  has_status_ = true;
  cache_info_ = info;
  client_->didChangeCacheAssociation();
}

void WebApplicationCacheHostImpl::OnStatusChanged(appcache::Status status) {
  if (has_status_)
    status_ = status;
}

void WebApplicationCacheHostImpl::OnEventRaised(appcache::EventID event_id) {
  DCHECK(event_id != PROGRESS_EVENT);  // See OnProgressEventRaised.
  DCHECK(event_id != ERROR_EVENT);  // See OnErrorEventRaised.

  // Emit logging output prior to calling out to script as we can get
  // deleted within the script event handler.
  const char* kFormatString = "Application Cache %s event";
  std::string message = base::StringPrintf(kFormatString,
                                           kEventNames[event_id]);
  OnLogMessage(LOG_INFO, message);

  // Most events change the status. Clear out what we know so that the latest
  // status will be obtained from the backend.
  has_status_ = false;
  has_cached_status_ = false;
  client_->notifyEventListener(static_cast<EventID>(event_id));
}

void WebApplicationCacheHostImpl::OnProgressEventRaised(
    const GURL& url, int num_total, int num_complete) {
  // Emit logging output prior to calling out to script as we can get
  // deleted within the script event handler.
  const char* kFormatString = "Application Cache Progress event (%d of %d) %s";
  std::string message = base::StringPrintf(kFormatString, num_complete,
                                           num_total, url.spec().c_str());
  OnLogMessage(LOG_INFO, message);

  client_->notifyProgressEventListener(url, num_total, num_complete);
}

void WebApplicationCacheHostImpl::OnErrorEventRaised(
    const std::string& message) {
  // Emit logging output prior to calling out to script as we can get
  // deleted within the script event handler.
  const char* kFormatString = "Application Cache Error event: %s";
  std::string full_message = base::StringPrintf(kFormatString,
                                                message.c_str());
  OnLogMessage(LOG_ERROR, full_message);

  // Most events change the status. Clear out what we know so that the latest
  // status will be obtained from the backend.
  has_status_ = false;
  has_cached_status_ = false;
  client_->notifyEventListener(static_cast<EventID>(ERROR_EVENT));
}

void WebApplicationCacheHostImpl::willStartMainResourceRequest(
    WebURLRequest& request) {
  request.setAppCacheHostID(host_id_);

  original_main_resource_url_ = ClearUrlRef(request.url());

  std::string method = request.httpMethod().utf8();
  is_get_method_ = (method == kHttpGETMethod);
  DCHECK(method == StringToUpperASCII(method));
}

void WebApplicationCacheHostImpl::willStartSubResourceRequest(
    WebURLRequest& request) {
  request.setAppCacheHostID(host_id_);
}

void WebApplicationCacheHostImpl::selectCacheWithoutManifest() {
  // Reset any previous status values we've received from the backend
  // since we're now selecting a new cache.
  has_status_ = false;
  has_cached_status_ = false;
  is_new_master_entry_ = NO;
  backend_->SelectCache(host_id_, document_url_,
                        document_response_.appCacheID(),
                        GURL());
}

void WebApplicationCacheHostImpl::getAssociatedCacheInfo(
    WebApplicationCacheHost::CacheInfo* info) {
  if (!cache_info_.is_complete)
    return;
  info->manifestURL = cache_info_.manifest_url;
  info->creationTime = cache_info_.creation_time.ToDoubleT();
  info->updateTime = cache_info_.last_update_time.ToDoubleT();
  info->totalSize = cache_info_.size;
}

void WebApplicationCacheHostImpl::getResourceList(
    WebVector<ResourceInfo>* resources) {
  if (!cache_info_.is_complete)
    return;
  std::vector<AppCacheResourceInfo> resource_infos;
  backend_->GetResourceList(host_id_, &resource_infos);

  WebVector<ResourceInfo> web_resources(resource_infos.size());
  // Convert resource_infos to WebKit API.
  for (size_t i = 0; i < resource_infos.size(); ++i) {
    web_resources[i].size = resource_infos[i].size;
    web_resources[i].isMaster = resource_infos[i].is_master;
    web_resources[i].isExplicit = resource_infos[i].is_explicit;
    web_resources[i].isManifest = resource_infos[i].is_manifest;
    web_resources[i].isForeign = resource_infos[i].is_foreign;
    web_resources[i].isFallback = resource_infos[i].is_fallback;
    web_resources[i].url = resource_infos[i].url;
  }

  resources->swap(web_resources);
}

bool WebApplicationCacheHostImpl::selectCacheWithManifest(
    const WebURL& manifest_url) {
  // Reset any previous status values we've received from the backend
  // since we're now selecting a new cache.
  has_status_ = false;
  has_cached_status_ = false;

  GURL manifest_gurl(ClearUrlRef(manifest_url));

  // 6.9.6 The application cache selection algorithm
  // Check for new 'master' entries.
  if (document_response_.appCacheID() == kNoCacheId) {
    if (is_scheme_supported_ && is_get_method_ &&
        (manifest_gurl.GetOrigin() == document_url_.GetOrigin())) {
      is_new_master_entry_ = YES;
    } else {
      is_new_master_entry_ = NO;
      manifest_gurl = GURL();
    }
    backend_->SelectCache(host_id_, document_url_,
                          kNoCacheId, manifest_gurl);
    return true;
  }

  DCHECK(is_new_master_entry_ = NO);

  // 6.9.6 The application cache selection algorithm
  // Check for 'foreign' entries.
  GURL document_manifest_gurl(document_response_.appCacheManifestURL());
  if (document_manifest_gurl != manifest_gurl) {
    backend_->MarkAsForeignEntry(host_id_, document_url_,
                                 document_response_.appCacheID());
    has_cached_status_ = true;
    cached_status_ = UNCACHED;
    return false;  // the navigation will be restarted
  }

  // Its a 'master' entry thats already in the cache.
  backend_->SelectCache(host_id_, document_url_,
                        document_response_.appCacheID(),
                        manifest_gurl);
  return true;
}

void WebApplicationCacheHostImpl::didReceiveResponseForMainResource(
    const WebURLResponse& response) {
  document_response_ = response;
  document_url_ = ClearUrlRef(document_response_.url());
  if (document_url_ != original_main_resource_url_)
    is_get_method_ = true;  // A redirect was involved.
  original_main_resource_url_ = GURL();

  is_scheme_supported_ =  IsSchemeSupported(document_url_);
  if ((document_response_.appCacheID() != kNoCacheId) ||
      !is_scheme_supported_ || !is_get_method_)
    is_new_master_entry_ = NO;
}

void WebApplicationCacheHostImpl::didReceiveDataForMainResource(
    const char* data, int len) {
  if (is_new_master_entry_ == NO)
    return;
  // TODO(michaeln): write me
}

void WebApplicationCacheHostImpl::didFinishLoadingMainResource(bool success) {
  if (is_new_master_entry_ == NO)
    return;
  // TODO(michaeln): write me
}

WebApplicationCacheHost::Status WebApplicationCacheHostImpl::status() {
  // We're careful about the status value to avoid race conditions.
  //
  // Generally the webappcachehost sends an async stream of messages to the
  // backend, and receives an asyncronous stream of events from the backend.
  // In the backend, all operations are serialized and as state changes
  // 'events' are streamed out to relevant parties. In particular the
  // 'SelectCache' message is async. Regular page loading and navigation
  // involves two non-blocking ipc calls: RegisterHost + SelectCache.
  //
  // However, the page can call the scriptable API in advance of a cache
  // selection being complete (and/or in advance of the webappcachehost having
  // received the event about completion). In that case, we force an end-to-end
  // fetch of the 'status' value, and cache that value seperately from the
  // value we receive via the async event stream. We'll use that cached value
  // until cache selection is complete.
  if (has_status_)
    return static_cast<WebApplicationCacheHost::Status>(status_);

  if (!has_cached_status_) {
    cached_status_ = backend_->GetStatus(host_id_);
    has_cached_status_ = true;
  }
  return static_cast<WebApplicationCacheHost::Status>(cached_status_);
}

bool WebApplicationCacheHostImpl::startUpdate() {
  return backend_->StartUpdate(host_id_);
}

bool WebApplicationCacheHostImpl::swapCache() {
  // Cache status will change when cache is swapped. Clear out any saved idea
  // of status so that backend will be queried for actual status.
  has_status_ = false;
  has_cached_status_ = false;
  return backend_->SwapCache(host_id_);
}

}  // appcache namespace