Web restrictions component.

components/web_restrictions/browser/web_restrictions_client.cc

+// Copyright 2015 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/web_restrictions/browser/web_restrictions_client.h"
+
+#include "base/android/jni_string.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/thread_task_runner_handle.h"
+#include "content/public/browser/browser_thread.h"
+#include "jni/WebRestrictionsClient_jni.h"
+
+namespace web_restrictions {
+
+namespace {
+
+const size_t kMaxCacheSize = 100;
+
+bool RequestPermissionTask(
+    const GURL& url,
+    const base::android::JavaRef<jobject>& java_provider) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  return Java_WebRestrictionsClient_requestPermission(
+      env, java_provider.obj(),
+      base::android::ConvertUTF8ToJavaString(env, url.spec()).obj());
+}
+
+bool CheckSupportsRequestTask(
+    const base::android::JavaRef<jobject>& java_provider) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  return Java_WebRestrictionsClient_supportsRequest(env, java_provider.obj());
+}
+
+}  // namespace
+
+// static
+bool WebRestrictionsClient::Register(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+WebRestrictionsClient::WebRestrictionsClient()
+    : initialized_(false), supports_request_(false) {
+  single_thread_task_runner_ = base::ThreadTaskRunnerHandle::Get();
+  base::SequencedWorkerPool* worker_pool =
+      content::BrowserThread::GetBlockingPool();
+  background_task_runner_ =
+      worker_pool->GetSequencedTaskRunnerWithShutdownBehavior(
+          worker_pool->GetSequenceToken(),
+          base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+}
+
+WebRestrictionsClient::~WebRestrictionsClient() {
+  if (java_provider_.is_null())
+    return;
+  JNIEnv* env = base::android::AttachCurrentThread();
+  Java_WebRestrictionsClient_onDestroy(env, java_provider_.obj());
+  java_provider_.Reset();
+}
+
+void WebRestrictionsClient::SetAuthority(
+    const std::string& content_provider_authority) {
+  DCHECK(single_thread_task_runner_->BelongsToCurrentThread());
+  // Destroy any existing content resolver.
+  JNIEnv* env = base::android::AttachCurrentThread();
+  if (!java_provider_.is_null()) {
+    Java_WebRestrictionsClient_onDestroy(env, java_provider_.obj());
+    java_provider_.Reset();
+  }
+  ClearCache();
+  provider_authority_ = content_provider_authority;
+
+  // Initialize the content resolver.
+  initialized_ = !content_provider_authority.empty();
+  if (!initialized_)
+    return;
+  java_provider_.Reset(Java_WebRestrictionsClient_create(
+      env,
+      base::android::ConvertUTF8ToJavaString(env, content_provider_authority)
+          .obj(),
+      reinterpret_cast<jlong>(this)));
+  supports_request_ = false;
+  base::PostTaskAndReplyWithResult(
+      content::BrowserThread::GetBlockingPool(), FROM_HERE,
+      base::Bind(&CheckSupportsRequestTask, java_provider_),
+      base::Bind(&WebRestrictionsClient::RequestSupportKnown,
+                 base::Unretained(this), provider_authority_));
+}
+
+UrlAccess WebRestrictionsClient::ShouldProceed(
+    bool is_main_frame,
+    const GURL& url,
+    const base::Callback<void(bool)>& callback) {
+  DCHECK(single_thread_task_runner_->BelongsToCurrentThread());
+  if (!initialized_)
+    return ALLOW;
+  auto iter = url_access_cache_.find(url);
+  if (iter != url_access_cache_.end()) {
+    RecordURLAccess(url);
+    return iter->second ? ALLOW : DISALLOW;
+  }
+  base::PostTaskAndReplyWithResult(
+      background_task_runner_.get(), FROM_HERE,
+      base::Bind(&WebRestrictionsClient::ShouldProceedTask, url,
+                 java_provider_),
+      base::Bind(&WebRestrictionsClient::OnShouldProceedComplete,
+                 base::Unretained(this), provider_authority_, url, callback));
+
+  return PENDING;
+}
+
+bool WebRestrictionsClient::SupportsRequest() const {
+  return initialized_ && supports_request_;
+}
+
+bool WebRestrictionsClient::GetErrorHtml(const GURL& url,
+                                         std::string* error_page) const {
+  DCHECK(single_thread_task_runner_->BelongsToCurrentThread());
+  if (!initialized_)
+    return false;
+  auto iter = error_page_cache_.find(url);
+  if (iter == error_page_cache_.end())
+    return false;
+  *error_page = iter->second;
+  return true;
+}
+
+void WebRestrictionsClient::RequestPermission(
+    const GURL& url,
+    const base::Callback<void(bool)>& request_success) {
+  if (!initialized_) {
+    request_success.Run(false);
+    return;
+  }
+  base::PostTaskAndReplyWithResult(
+      background_task_runner_.get(), FROM_HERE,
+      base::Bind(&RequestPermissionTask, url, java_provider_), request_success);
+}
+
+void WebRestrictionsClient::OnWebRestrictionsChanged() {
+  single_thread_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&WebRestrictionsClient::ClearCache, base::Unretained(this)));
+}
+
+void WebRestrictionsClient::RecordURLAccess(const GURL& url) {
+  DCHECK(single_thread_task_runner_->BelongsToCurrentThread());
+  // Move the URL to the front of the cache.
+  recent_urls_.remove(url);
+  recent_urls_.push_front(url);
+}
+
+void WebRestrictionsClient::UpdateCache(std::string provider_authority,
+                                        GURL url,
+                                        bool should_proceed,
+                                        std::string error_page) {
+  DCHECK(single_thread_task_runner_->BelongsToCurrentThread());
+  // If the webrestrictions provider changed when the old one was being queried,
+  // do not update the cache for the new provider.
+  if (provider_authority != provider_authority_)
+    return;
+  RecordURLAccess(url);
+  if (recent_urls_.size() >= kMaxCacheSize) {
+    url_access_cache_.erase(recent_urls_.back());
+    error_page_cache_.erase(recent_urls_.back());
+    recent_urls_.pop_back();
+  }
+  url_access_cache_[url] = should_proceed;
+  if (!error_page.empty()) {
+    error_page_cache_[url] = error_page;
+  } else {
+    error_page_cache_.erase(url);
+  }
+}
+
+void WebRestrictionsClient::RequestSupportKnown(std::string provider_authority,
+                                                bool supports_request) {
+  // |supports_request_| is initialized to false.
+  DCHECK(!supports_request_);
+  DCHECK(single_thread_task_runner_->BelongsToCurrentThread());
+  // If the webrestrictions provider changed when the old one was being queried,
+  // ignore the result.
+  if (provider_authority != provider_authority_)
+    return;
+  supports_request_ = supports_request;
+}
+
+void WebRestrictionsClient::OnShouldProceedComplete(
+    std::string provider_authority,
+    const GURL& url,
+    const base::Callback<void(bool)>& callback,
+    const ShouldProceedResult& result) {
+  UpdateCache(provider_authority, url, result.ok_to_proceed, result.error_page);
+  callback.Run(result.ok_to_proceed);
+}
+
+void WebRestrictionsClient::ClearCache() {
+  DCHECK(single_thread_task_runner_->BelongsToCurrentThread());
+  error_page_cache_.clear();
+  url_access_cache_.clear();
+  recent_urls_.clear();
+}
+
+// static
+WebRestrictionsClient::ShouldProceedResult
+WebRestrictionsClient::ShouldProceedTask(

[Bernhard Bauer, 2016/02/19 13:46:26]

Does this need to be a private static method, or could it also go into the
anonymous namespace above?

[aberent, 2016/02/19 19:40:08]

Sadly it can't unless I make ShouldProceedResult public.

+    const GURL& url,
+    const base::android::JavaRef<jobject>& java_provider) {
+  WebRestrictionsClient::ShouldProceedResult result;
+  JNIEnv* env = base::android::AttachCurrentThread();
+  base::android::ScopedJavaLocalRef<jobject> j_result =
+      Java_WebRestrictionsClient_shouldProceed(
+          env, java_provider.obj(),
+          base::android::ConvertUTF8ToJavaString(env, url.spec()).obj());
+  result.ok_to_proceed =
+      Java_ShouldProceedResult_shouldProceed(env, j_result.obj());
+  base::android::ScopedJavaLocalRef<jstring> j_error_page =
+      Java_ShouldProceedResult_getErrorPage(env, j_result.obj());
+  if (j_error_page.obj() == nullptr) {

[Bernhard Bauer, 2016/02/19 13:46:26]

You can use .is_null() for this.

[aberent, 2016/02/19 19:40:07]

Done.

+    result.error_page = nullptr;

[Bernhard Bauer, 2016/02/19 13:46:26]

And this isn't really necessary, as the string will start out empty anyway.

(Also, why nullptr?)

[aberent, 2016/02/19 19:40:08]

Done.

+  } else {
+    result.error_page =

[Bernhard Bauer, 2016/02/19 13:46:26]

And finally, here you could just pass a pointer to the string as an outparam.

[aberent, 2016/02/19 19:40:08]

This has to be passed to the OnShouldProceedComplete. Splitting it into a
seperate parameter so breaks the model of PostTaskAndReplyWithResult() which
expects a single object to be passed from the task to the reply function. I
could, of course, use PostTaskAndReply(), but would then need my own handling of
the lifetime of the result objects.

[Bernhard Bauer, 2016/02/22 12:39:16]

Sorry, I meant using the outparam form of ConvertJavaStringToUTF8 to set the
error page.

[aberent, 2016/02/23 13:52:37]

Done.

[Bernhard Bauer, 2016/02/23 14:29:13]

Not really? 😃

[aberent, 2016/02/23 16:26:51]

Done. Really, this time.

+        base::android::ConvertJavaStringToUTF8(env, j_error_page.obj());
+  }
+  return result;
+}
+
+void NotifyWebRestrictionsChanged(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& clazz,
+    jlong provider_ptr) {
+  WebRestrictionsClient* provider =
+      reinterpret_cast<WebRestrictionsClient*>(provider_ptr);
+  // TODO(knn): Also reload existing interstitials/error pages.
+  provider->OnWebRestrictionsChanged();
+}
+
+}  // namespace web_restrictions