components/zoom/zoom_controller.cc

// Copyright (c) 2012 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 "components/zoom/zoom_controller.h"

#include "components/zoom/zoom_event_manager.h"
#include "components/zoom/zoom_observer.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/host_zoom_map.h"
#include "content/public/browser/navigation_details.h"
#include "content/public/browser/navigation_entry.h"
#include "content/public/browser/navigation_handle.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/web_contents.h"
#include "content/public/common/page_type.h"
#include "content/public/common/page_zoom.h"
#include "net/base/url_util.h"

DEFINE_WEB_CONTENTS_USER_DATA_KEY(zoom::ZoomController);

using content::BrowserThread;

namespace zoom {

double ZoomController::GetZoomLevelForWebContents(
    const content::WebContents* web_contents) {
  if (!web_contents)
    return 0.0;

  auto* zoom_controller = FromWebContents(web_contents);
  if (zoom_controller)
    return zoom_controller->GetZoomLevel();

  return content::HostZoomMap::GetZoomLevel(web_contents);
}

ZoomController::ZoomController(content::WebContents* web_contents)
    : content::WebContentsObserver(web_contents),
      can_show_bubble_(true),
      zoom_mode_(ZOOM_MODE_DEFAULT),
      zoom_level_(1.0),
      browser_context_(web_contents->GetBrowserContext()) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  host_zoom_map_ = content::HostZoomMap::GetForWebContents(web_contents);
  zoom_level_ = host_zoom_map_->GetDefaultZoomLevel();

  zoom_subscription_ = host_zoom_map_->AddZoomLevelChangedCallback(
      base::Bind(&ZoomController::OnZoomLevelChanged, base::Unretained(this)));

  UpdateState(std::string());
}

ZoomController::~ZoomController() {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
}

bool ZoomController::IsAtDefaultZoom() const {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  return content::ZoomValuesEqual(GetZoomLevel(), GetDefaultZoomLevel());
}

ZoomController::RelativeZoom ZoomController::GetZoomRelativeToDefault() const {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  double current_level = GetZoomLevel();
  double default_level = GetDefaultZoomLevel();
  if (content::ZoomValuesEqual(current_level, default_level))
    return ZOOM_AT_DEFAULT_ZOOM;
  if (current_level > default_level)
    return ZOOM_ABOVE_DEFAULT_ZOOM;
  return ZOOM_BELOW_DEFAULT_ZOOM;
}

void ZoomController::AddObserver(ZoomObserver* observer) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  observers_.AddObserver(observer);
}

void ZoomController::RemoveObserver(ZoomObserver* observer) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  observers_.RemoveObserver(observer);
}

double ZoomController::GetZoomLevel() const {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  return zoom_mode_ == ZOOM_MODE_MANUAL
             ? zoom_level_
             : content::HostZoomMap::GetZoomLevel(web_contents());
}

int ZoomController::GetZoomPercent() const {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  double zoom_factor = content::ZoomLevelToZoomFactor(GetZoomLevel());
  // Round double for return.
  return static_cast<int>(zoom_factor * 100 + 0.5);
}

bool ZoomController::SetZoomLevel(double zoom_level) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  // A client did not initiate this zoom change.
  return SetZoomLevelByClient(zoom_level, nullptr);
}

bool ZoomController::SetZoomLevelByClient(
    double zoom_level,
    const scoped_refptr<const ZoomRequestClient>& client) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  content::NavigationEntry* entry =
      web_contents()->GetController().GetLastCommittedEntry();
  // Cannot zoom in disabled mode. Also, don't allow changing zoom level on
  // a crashed tab, an error page or an interstitial page.
  if (zoom_mode_ == ZOOM_MODE_DISABLED ||
      !web_contents()->GetRenderViewHost()->IsRenderViewLive())
    return false;

  // Store client data so the |client| can be attributed when the zoom
  // change completes. We expect that by the time this function returns that
  // any observers that require this information will have requested it.
  last_client_ = client;

  // Do not actually rescale the page in manual mode.
  if (zoom_mode_ == ZOOM_MODE_MANUAL) {
    // If the zoom level hasn't changed, early out to avoid sending an event.
    if (content::ZoomValuesEqual(zoom_level_, zoom_level))
      return true;

    double old_zoom_level = zoom_level_;
    zoom_level_ = zoom_level;

    // TODO(wjmaclean) Do we care about filling in host/scheme here?
    content::HostZoomMap::ZoomLevelChange change;
    change.mode = content::HostZoomMap::ZOOM_CHANGED_TEMPORARY_ZOOM;
    change.zoom_level = zoom_level;
    ZoomEventManager::GetForBrowserContext(browser_context_)
        ->OnZoomLevelChanged(change);

    bool can_show_bubble = can_show_bubble_;
    if (client && client->ShouldSuppressBubble())
      can_show_bubble = false;

    ZoomChangedEventData zoom_change_data(web_contents(), old_zoom_level,
                                          zoom_level_, zoom_mode_,
                                          can_show_bubble);
    for (auto& observer : observers_)
      observer.OnZoomChanged(zoom_change_data);

    last_client_ = nullptr;
    return true;
  }

  content::HostZoomMap* zoom_map =
      content::HostZoomMap::GetForWebContents(web_contents());
  DCHECK(zoom_map);
  DCHECK(!event_data_);
  event_data_.reset(new ZoomChangedEventData(web_contents(), GetZoomLevel(),
                                             zoom_level, zoom_mode_,
                                             false /* can_show_bubble */));
  int process_id = web_contents()->GetRenderViewHost()->GetProcess()->GetID();
  int view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
  if (zoom_mode_ == ZOOM_MODE_ISOLATED ||
      zoom_map->UsesTemporaryZoomLevel(process_id, view_id)) {
    zoom_map->SetTemporaryZoomLevel(process_id, view_id, zoom_level);
  } else {
    if (!entry) {
      last_client_ = nullptr;
      // If we exit without triggering an update, we should clear event_data_,
      // else we may later trigger a DCHECK(event_data_).
      event_data_.reset();
      return false;
    }
    std::string host =
        net::GetHostOrSpecFromURL(content::HostZoomMap::GetURLFromEntry(entry));
    zoom_map->SetZoomLevelForHost(host, zoom_level);
  }

  DCHECK(!event_data_);
  last_client_ = nullptr;
  return true;
}

void ZoomController::SetZoomMode(ZoomMode new_mode) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  if (new_mode == zoom_mode_)
    return;

  content::HostZoomMap* zoom_map =
      content::HostZoomMap::GetForWebContents(web_contents());
  DCHECK(zoom_map);
  int process_id = web_contents()->GetRenderViewHost()->GetProcess()->GetID();
  int view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
  double original_zoom_level = GetZoomLevel();

  DCHECK(!event_data_);
  event_data_.reset(new ZoomChangedEventData(
      web_contents(), original_zoom_level, original_zoom_level, new_mode,
      new_mode != ZOOM_MODE_DEFAULT));

  switch (new_mode) {
    case ZOOM_MODE_DEFAULT: {
      content::NavigationEntry* entry =
          web_contents()->GetController().GetLastCommittedEntry();

      if (entry) {
        GURL url = content::HostZoomMap::GetURLFromEntry(entry);
        std::string host = net::GetHostOrSpecFromURL(url);

        if (zoom_map->HasZoomLevel(url.scheme(), host)) {
          // If there are other tabs with the same origin, then set this tab's
          // zoom level to match theirs. The temporary zoom level will be
          // cleared below, but this call will make sure this tab re-draws at
          // the correct zoom level.
          double origin_zoom_level =
              zoom_map->GetZoomLevelForHostAndScheme(url.scheme(), host);
          event_data_->new_zoom_level = origin_zoom_level;
          zoom_map->SetTemporaryZoomLevel(process_id, view_id,
                                          origin_zoom_level);
        } else {
          // The host will need a level prior to removing the temporary level.
          // We don't want the zoom level to change just because we entered
          // default mode.
          zoom_map->SetZoomLevelForHost(host, original_zoom_level);
        }
      }
      // Remove per-tab zoom data for this tab. No event callback expected.
      zoom_map->ClearTemporaryZoomLevel(process_id, view_id);
      break;
    }
    case ZOOM_MODE_ISOLATED: {
      // Unless the zoom mode was |ZOOM_MODE_DISABLED| before this call, the
      // page needs an initial isolated zoom back to the same level it was at
      // in the other mode.
      if (zoom_mode_ != ZOOM_MODE_DISABLED) {
        zoom_map->SetTemporaryZoomLevel(process_id, view_id,
                                        original_zoom_level);
      } else {
        // When we don't call any HostZoomMap set functions, we send the event
        // manually.
        for (auto& observer : observers_)
          observer.OnZoomChanged(*event_data_);
        event_data_.reset();
      }
      break;
    }
    case ZOOM_MODE_MANUAL: {
      // Unless the zoom mode was |ZOOM_MODE_DISABLED| before this call, the
      // page needs to be resized to the default zoom. While in manual mode,
      // the zoom level is handled independently.
      if (zoom_mode_ != ZOOM_MODE_DISABLED) {
        zoom_map->SetTemporaryZoomLevel(process_id, view_id,
                                        GetDefaultZoomLevel());
        zoom_level_ = original_zoom_level;
      } else {
        // When we don't call any HostZoomMap set functions, we send the event
        // manually.
        for (auto& observer : observers_)
          observer.OnZoomChanged(*event_data_);
        event_data_.reset();
      }
      break;
    }
    case ZOOM_MODE_DISABLED: {
      // The page needs to be zoomed back to default before disabling the zoom
      double new_zoom_level = GetDefaultZoomLevel();
      event_data_->new_zoom_level = new_zoom_level;
      zoom_map->SetTemporaryZoomLevel(process_id, view_id, new_zoom_level);
      break;
    }
  }
  // Any event data we've stored should have been consumed by this point.
  DCHECK(!event_data_);

  zoom_mode_ = new_mode;
}

void ZoomController::ResetZoomModeOnNavigationIfNeeded(const GURL& url) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  if (zoom_mode_ != ZOOM_MODE_ISOLATED && zoom_mode_ != ZOOM_MODE_MANUAL)
    return;

  int process_id = web_contents()->GetRenderViewHost()->GetProcess()->GetID();
  int view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
  content::HostZoomMap* zoom_map =
      content::HostZoomMap::GetForWebContents(web_contents());
  zoom_level_ = zoom_map->GetDefaultZoomLevel();
  double old_zoom_level = zoom_map->GetZoomLevel(web_contents());
  double new_zoom_level = zoom_map->GetZoomLevelForHostAndScheme(
      url.scheme(), net::GetHostOrSpecFromURL(url));
  event_data_.reset(new ZoomChangedEventData(web_contents(), old_zoom_level,
                                             new_zoom_level, ZOOM_MODE_DEFAULT,
                                             false /* can_show_bubble */));
  // The call to ClearTemporaryZoomLevel() doesn't generate any events from
  // HostZoomMap, but the call to UpdateState() at the end of this function
  // will notify our observers.
  // Note: it's possible the render_process/view ids have disappeared (e.g.
  // if we navigated to a new origin), but this won't cause a problem in the
  // call below.
  zoom_map->ClearTemporaryZoomLevel(process_id, view_id);
  zoom_mode_ = ZOOM_MODE_DEFAULT;
}

void ZoomController::DidFinishNavigation(
    content::NavigationHandle* navigation_handle) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  if (!navigation_handle->IsInMainFrame() || !navigation_handle->HasCommitted())
    return;

  if (navigation_handle->IsErrorPage())
    content::HostZoomMap::SendErrorPageZoomLevelRefresh(web_contents());

  if (!navigation_handle->IsSameDocument())
    ResetZoomModeOnNavigationIfNeeded(navigation_handle->GetURL());

  // If the main frame's content has changed, the new page may have a different
  // zoom level from the old one.
  UpdateState(std::string());
  DCHECK(!event_data_);
}

void ZoomController::WebContentsDestroyed() {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  // At this point we should no longer be sending any zoom events with this
  // WebContents.
  observers_.Clear();
}

void ZoomController::RenderFrameHostChanged(
    content::RenderFrameHost* old_host,
    content::RenderFrameHost* new_host) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  // If our associated HostZoomMap changes, update our event subscription.
  content::HostZoomMap* new_host_zoom_map =
      content::HostZoomMap::GetForWebContents(web_contents());
  if (new_host_zoom_map == host_zoom_map_)
    return;

  host_zoom_map_ = new_host_zoom_map;
  zoom_subscription_ = host_zoom_map_->AddZoomLevelChangedCallback(
      base::Bind(&ZoomController::OnZoomLevelChanged, base::Unretained(this)));
}

void ZoomController::OnZoomLevelChanged(
    const content::HostZoomMap::ZoomLevelChange& change) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  UpdateState(change.host);
}

void ZoomController::UpdateState(const std::string& host) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  // If |host| is empty, all observers should be updated.
  if (!host.empty()) {
    // Use the navigation entry's URL instead of the WebContents' so virtual
    // URLs work (e.g. chrome://settings). http://crbug.com/153950
    content::NavigationEntry* entry =
        web_contents()->GetController().GetLastCommittedEntry();
    if (!entry ||
        host != net::GetHostOrSpecFromURL(
                    content::HostZoomMap::GetURLFromEntry(entry))) {
      return;
    }
  }

  if (event_data_) {
    // For state changes initiated within the ZoomController, information about
    // the change should be sent.
    ZoomChangedEventData zoom_change_data = *event_data_;
    event_data_.reset();
    // The zoom bubble should not be shown for zoom changes where the host
    // is empty or when zoom level is not changed from default.
    const bool changed_from_default =
        zoom_change_data.new_zoom_level != zoom_change_data.old_zoom_level ||
        zoom_change_data.new_zoom_level != GetDefaultZoomLevel();
    zoom_change_data.can_show_bubble =
        can_show_bubble_ && !host.empty() && changed_from_default;
    for (auto& observer : observers_)
      observer.OnZoomChanged(zoom_change_data);
  } else {
    // TODO(wjmaclean) Should we consider having HostZoomMap send both old and
    // new zoom levels here?
    double zoom_level = GetZoomLevel();
    // We never show a zoom bubble for an event we didn't generate.
    ZoomChangedEventData zoom_change_data(web_contents(), zoom_level,
                                          zoom_level, zoom_mode_,
                                          false /* can_show_bubble */);
    for (auto& observer : observers_)
      observer.OnZoomChanged(zoom_change_data);
  }
}

void ZoomController::SetPageScaleFactorIsOneForTesting(bool is_one) {
  int process_id = web_contents()->GetRenderViewHost()->GetProcess()->GetID();
  int view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
  host_zoom_map_->SetPageScaleFactorIsOneForView(process_id, view_id, is_one);
}

bool ZoomController::PageScaleFactorIsOne() const {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  return content::HostZoomMap::PageScaleFactorIsOne(web_contents());
}

}  // namespace zoom