Create BlacklistManager, which will aggregate individual blacklists into one compiled one

chrome/browser/privacy_blacklist/blacklist_manager.cc

+// Copyright (c) 2009 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/privacy_blacklist/blacklist_manager.h"
+
+#include "base/message_loop.h"
+#include "base/task.h"
+#include "base/thread.h"
+#include "chrome/browser/privacy_blacklist/blacklist.h"
+#include "chrome/browser/privacy_blacklist/blacklist_io.h"
+#include "chrome/browser/profile.h"
+#include "chrome/common/chrome_constants.h"
+#include "chrome/common/notification_source.h"
+#include "chrome/common/notification_type.h"
+
+// Base class for tasks that use BlacklistManager. It ensures that the
+// BlacklistManager won't get destroyed while we need it, and that it
+// will be destroyed always on the same thread. That's why we use
+// a custom Task instead of just NewRunnableMethod.
+class BlacklistManagerTask : public Task {
+ public:
+  explicit BlacklistManagerTask(BlacklistManager* manager)
+      : manager_(manager),
+        original_loop_(MessageLoop::current()) {
+    DCHECK(original_loop_);
+    manager->AddRef();
+  }
+
+  ~BlacklistManagerTask() {
+    original_loop_->ReleaseSoon(FROM_HERE, manager_);
+  }
+
+ protected:
+  BlacklistManager* blacklist_manager() const { return manager_; }
+
+ private:
+  BlacklistManager* manager_;
+
+  MessageLoop* original_loop_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlacklistManagerTask);
+};
+
+BlacklistPathProvider::~BlacklistPathProvider() {
+}
+
+class BlacklistManager::CompileBlacklistTask : public BlacklistManagerTask {
+ public:
+  CompileBlacklistTask(BlacklistManager* manager,
+                       const FilePath& destination_blacklist,
+                       const std::vector<FilePath>& source_blacklists)
+      : BlacklistManagerTask(manager),
+        destination_blacklist_(destination_blacklist),
+        source_blacklists_(source_blacklists) {
+  }
+
+  virtual void Run() {
+    BlacklistIO io;
+    bool success = true;
+
+    for (std::vector<FilePath>::const_iterator i = source_blacklists_.begin();
+         i != source_blacklists_.end(); ++i) {
+      if (!io.Read(*i)) {
+        success = false;
+        break;
+      }
+    }
+
+    // Only overwrite the current compiled blacklist if we read all source
+    // files successfully.
+    if (success)
+      success = io.Write(destination_blacklist_);
+
+    blacklist_manager()->OnBlacklistCompilationFinished(success);
+  }
+
+ private:
+  FilePath destination_blacklist_;
+
+  std::vector<FilePath> source_blacklists_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompileBlacklistTask);
+};
+
+class BlacklistManager::ReadBlacklistTask : public BlacklistManagerTask {
+ public:
+  ReadBlacklistTask(BlacklistManager* manager, const FilePath& blacklist_path)
+      : BlacklistManagerTask(manager),
+        blacklist_path_(blacklist_path) {
+  }
+
+  virtual void Run() {
+    Blacklist* blacklist = new Blacklist(blacklist_path_);
+    blacklist_manager()->OnBlacklistReadFinished(blacklist);
+  }
+
+ private:
+  FilePath blacklist_path_;
+
+  DISALLOW_COPY_AND_ASSIGN(ReadBlacklistTask);
+};
+
+BlacklistManager::BlacklistManager(Profile* profile,
+                                   base::Thread* backend_thread)
+    : compiled_blacklist_path_(
+        profile->GetPath().Append(chrome::kPrivacyBlacklistFileName)),
+      compiling_blacklist_(false),
+      backend_thread_(backend_thread) {
+  registrar_.Add(this,
+                 NotificationType::PRIVACY_BLACKLIST_PATH_PROVIDER_UPDATED,
+                 Source<Profile>(profile));
+  ReadBlacklist();
+}
+
+void BlacklistManager::RegisterBlacklistPathProvider(
+    BlacklistPathProvider* provider) {
+  DCHECK(providers_.find(provider) == providers_.end());
+  providers_.insert(provider);
+}
+
+void BlacklistManager::UnregisterBlacklistPathProvider(
+    BlacklistPathProvider* provider) {
+  DCHECK(providers_.find(provider) != providers_.end());
+  providers_.erase(provider);
+}
+
+void BlacklistManager::Observe(NotificationType type,
+                               const NotificationSource& source,
+                               const NotificationDetails& details) {
+  DCHECK(type == NotificationType::PRIVACY_BLACKLIST_PATH_PROVIDER_UPDATED);
+  CompileBlacklist();
+}
+
+void BlacklistManager::CompileBlacklist() {
+  if (compiling_blacklist_) {
+    // If we end up here, that means that initial compile succeeded,
+    // but then we couldn't read back the resulting Blacklist. Return early
+    // to avoid a potential infinite loop.
+    // TODO(phajdan.jr): Report the error.
+    compiling_blacklist_ = false;
+    return;
+  }
+
+  compiling_blacklist_ = true;
+
+  std::vector<FilePath> source_blacklists;
+
+  for (ProvidersSet::iterator provider = providers_.begin();
+       provider != providers_.end(); ++provider) {
+    std::vector<FilePath> provided_paths((*provider)->GetBlacklistPaths());
+    source_blacklists.insert(source_blacklists.end(),
+                             provided_paths.begin(), provided_paths.end());
+  }
+
+  RunTaskOnBackendThread(new CompileBlacklistTask(this, compiled_blacklist_path_,
+                                                source_blacklists));
+}
+
+void BlacklistManager::ReadBlacklist() {
+  RunTaskOnBackendThread(new ReadBlacklistTask(this, compiled_blacklist_path_));
+}
+
+void BlacklistManager::OnBlacklistCompilationFinished(bool success) {
+  if (success) {
+    ReadBlacklist();
+  } else {
+    // TODO(phajdan.jr): Report the error.
+  }
+}
+
+void BlacklistManager::OnBlacklistReadFinished(Blacklist* blacklist) {
+  if (blacklist->is_good()) {
+    compiled_blacklist_.reset(blacklist);
+    compiling_blacklist_ = false;
+  } else {
+    delete blacklist;
+    CompileBlacklist();
+  }
+}
+
+void BlacklistManager::RunTaskOnBackendThread(Task* task) {
+  if (backend_thread_) {
+    backend_thread_->message_loop()->PostTask(FROM_HERE, task);
+  } else {
+    task->Run();
+    delete task;
+  }
+}