chrome/browser/web_applications/web_app_url_loader.cc

// Copyright 2019 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/web_applications/web_app_url_loader.h"

#include <memory>
#include <utility>

#include "base/bind.h"
#include "base/callback.h"
#include "base/check.h"
#include "base/logging.h"
#include "base/memory/weak_ptr.h"
#include "base/metrics/histogram_functions.h"
#include "base/threading/thread_task_runner_handle.h"
#include "base/timer/timer.h"
#include "content/public/browser/navigation_controller.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/web_contents_observer.h"
#include "content/public/common/url_constants.h"
#include "ui/base/page_transition_types.h"
#include "url/gurl.h"

namespace web_app {
namespace {
using UrlComparison = WebAppUrlLoader::UrlComparison;

bool EqualsWithComparison(const GURL& a,
                          const GURL& b,
                          UrlComparison url_comparison) {
  DCHECK(a.is_valid());
  DCHECK(b.is_valid());
  if (a == b)
    return true;
  GURL::Replacements replace;
  switch (url_comparison) {
    case UrlComparison::kExact:
      return false;
    case UrlComparison::kSameOrigin:
      replace.ClearPath();
      [[fallthrough]];
    case UrlComparison::kIgnoreQueryParamsAndRef:
      replace.ClearQuery();
      replace.ClearRef();
      break;
  }
  return a.ReplaceComponents(replace) == b.ReplaceComponents(replace);
}

class LoaderTask : public content::WebContentsObserver {
 public:
  LoaderTask() = default;
  LoaderTask(const LoaderTask&) = delete;
  LoaderTask& operator=(const LoaderTask&) = delete;
  LoaderTask(LoaderTask&&) = delete;
  LoaderTask& operator=(LoaderTask&&) = delete;
  ~LoaderTask() override = default;

  void LoadUrl(const GURL& url,
               content::WebContents* web_contents,
               UrlComparison url_comparison,
               WebAppUrlLoader::ResultCallback callback) {
    url_ = url;
    url_comparison_ = url_comparison;
    callback_ = std::move(callback);
    Observe(web_contents);

    content::NavigationController::LoadURLParams load_params(url);
    load_params.transition_type = ui::PAGE_TRANSITION_GENERATED;

    web_contents->GetController().LoadURLWithParams(load_params);

    timer_.Start(FROM_HERE, WebAppUrlLoader::kSecondsToWaitForWebContentsLoad,
                 base::BindOnce(&LoaderTask::OnLoadUrlTimeout,
                                // OneShotTimer is owned by this class and
                                // it guarantees that it will never run after
                                // it's destroyed.
                                base::Unretained(this)));
  }

  // WebContentsObserver
  // DidFinishLoad doesn't always get called after the page has fully loaded.
  // TODO(ortuno): Use DidStopLoading instead.
  void DidFinishLoad(content::RenderFrameHost* render_frame_host,
                     const GURL& validated_url) override {
    if (IsSubframeLoad(render_frame_host)) {
      return;
    }

    // Flush all DidFinishLoad events until about:blank loaded.
    if ((url_.IsAboutBlank() && !validated_url.IsAboutBlank()) ||
        (!url_.IsAboutBlank() && validated_url.IsAboutBlank())) {
      return;
    }

    timer_.Stop();

    if (validated_url == content::kUnreachableWebDataURL) {
      // Navigation ends up in an error page. For example, network errors and
      // policy blocked URLs.
      // TODO(https://crbug.com/1071300): Handle error codes appropriately.
      PostResultTask(WebAppUrlLoader::Result::kFailedErrorPageLoaded);
      return;
    }

    if (EqualsWithComparison(validated_url, url_, url_comparison_)) {
      PostResultTask(WebAppUrlLoader::Result::kUrlLoaded);
      return;
    }
    LOG(ERROR) << "Error loading " << url_ << "  page redirected to "
               << validated_url;
    PostResultTask(WebAppUrlLoader::Result::kRedirectedUrlLoaded);
  }

  bool IsSubframeLoad(content::RenderFrameHost* render_frame_host) const {
    return web_contents()->GetPrimaryMainFrame() != render_frame_host;
  }

  void DidFailLoad(content::RenderFrameHost* render_frame_host,
                   const GURL& validated_url,
                   int error_code) override {
    if (IsSubframeLoad(render_frame_host)) {
      return;
    }

    // Flush all DidFailLoad events until about:blank loaded.
    if (url_.IsAboutBlank())
      return;

    timer_.Stop();

    LOG(ERROR) << "Error loading " << url_ << "  page failed to load.";
    PostResultTask(WebAppUrlLoader::Result::kFailedUnknownReason);
  }

  void WebContentsDestroyed() override {
    timer_.Stop();
    PostResultTask(WebAppUrlLoader::Result::kFailedWebContentsDestroyed);
  }

 private:
  void OnLoadUrlTimeout() {
    web_contents()->Stop();
    LOG(ERROR) << "Error loading " << url_ << " page took too long to load.";
    PostResultTask(WebAppUrlLoader::Result::kFailedPageTookTooLong);
  }

  void PostResultTask(WebAppUrlLoader::Result result) {
    Observe(nullptr);
    // Post a task to avoid reentrancy issues e.g. adding a WebContentsObserver
    // while a previous observer call is being executed.
    base::ThreadTaskRunnerHandle::Get()->PostTask(
        FROM_HERE, base::BindOnce(std::move(callback_), result));
  }

  GURL url_;
  UrlComparison url_comparison_;
  WebAppUrlLoader::ResultCallback callback_;

  base::OneShotTimer timer_;

  base::WeakPtrFactory<LoaderTask> weak_ptr_factory_{this};
};

}  // namespace

WebAppUrlLoader::WebAppUrlLoader() = default;

WebAppUrlLoader::~WebAppUrlLoader() = default;

void WebAppUrlLoader::LoadUrl(const GURL& url,
                              content::WebContents* web_contents,
                              UrlComparison url_comparison,
                              ResultCallback callback) {
  auto loader_task = std::make_unique<LoaderTask>();
  auto* loader_task_ptr = loader_task.get();
  loader_task_ptr->LoadUrl(
      url, web_contents, url_comparison,
      base::BindOnce(
          [](ResultCallback callback, std::unique_ptr<LoaderTask> task,
             Result result) {
            std::move(callback).Run(result);
            task.reset();
          },
          std::move(callback), std::move(loader_task)));
}

void WebAppUrlLoader::PrepareForLoad(content::WebContents* web_contents,
                                     ResultCallback callback) {
  LoadUrl(GURL(url::kAboutBlankURL), web_contents, UrlComparison::kExact,
          base::BindOnce(
              [](ResultCallback callback, Result result) {
                base::UmaHistogramEnumeration(
                    "Webapp.WebAppUrlLoaderPrepareForLoadResult", result);
                std::move(callback).Run(result);
              },
              std::move(callback)));
}

const char* ConvertUrlLoaderResultToString(WebAppUrlLoader::Result result) {
  using Result = WebAppUrlLoader::Result;
  switch (result) {
    case Result::kUrlLoaded:
      return "UrlLoaded";
    case Result::kRedirectedUrlLoaded:
      return "RedirectedUrlLoaded";
    case Result::kFailedUnknownReason:
      return "FailedUnknownReason";
    case Result::kFailedPageTookTooLong:
      return "FailedPageTookTooLong";
    case Result::kFailedWebContentsDestroyed:
      return "FailedWebContentsDestroyed";
    case Result::kFailedErrorPageLoaded:
      return "FailedErrorPageLoaded";
  }
}

}  // namespace web_app