DnsConfigService and a posix implementation

net/dns/dns_config_service_posix.h

+// Copyright (c) 2011 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.
+
+#ifndef NET_DNS_DNS_CONFIG_SERVICE_POSIX_H_
+#define NET_DNS_DNS_CONFIG_SERVICE_POSIX_H_
+#pragma once
+
+#include <resolv.h>
+
+#include "base/compiler_specific.h"
+#include "base/files/file_path_watcher.h"
+#include "base/memory/ref_counted.h"
+#include "base/observer_list.h"
+#include "base/scoped_ptr.h"
+#include "base/threading/non_thread_safe.h"
+#include "net/base/net_export.h"
+#include "net/dns/dns_config_service.h"
+
+namespace net {
+
+class NET_EXPORT_PRIVATE DnsConfigServicePosix :
+   public NON_EXPORTED_BASE(DnsConfigService),
+   public NON_EXPORTED_BASE(base::NonThreadSafe) {
+ public:
+  class ResolverLib;
+  class FilePathWatcherShim;
+  class FilePathWatcherFactory;
+  class WatcherDelegate;
+
+  DnsConfigServicePosix();
+  virtual ~DnsConfigServicePosix();
+
+  virtual void AddObserver(Observer* observer) OVERRIDE;
+  virtual void RemoveObserver(Observer* observer) OVERRIDE;
+  virtual void Watch() OVERRIDE;
+
+  // Takes ownership of |lib|. Must be set before Watch.
+  void set_resolver_lib(ResolverLib* lib) {
+    DCHECK(!watcher_delegate_.get());
+    resolver_lib_.reset(lib);
+  }
+
+  // Takes ownership of |factory|. Must be set before Watch.
+  void set_watcher_factory(FilePathWatcherFactory* factory) {
+    DCHECK(!watcher_delegate_.get());
+    watcher_factory_.reset(factory);
+  }
+
+ private:
+  void OnConfigRead(const DnsConfig& config);
+
+  // Configure a FilePathWatcher and install watcher_delegate_. Executed each
+  // time FilePathWatcher fails.
+  void StartWatch();
+
+  DnsConfig dns_config_;
+  // True after first OnConfigChanged, that is, dns_config_ is valid.
+  bool have_config_;
+
+  scoped_ptr<ResolverLib> resolver_lib_;
+  scoped_ptr<FilePathWatcherFactory> watcher_factory_;
+  scoped_ptr<FilePathWatcherShim> resolv_file_watcher_;
+  scoped_refptr<WatcherDelegate> watcher_delegate_;
+  ObserverList<Observer> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(DnsConfigServicePosix);
+};
+
+
+// Allows mocking res_ninit.
+class NET_EXPORT_PRIVATE DnsConfigServicePosix::ResolverLib :
+    public NON_EXPORTED_BASE(base::NonThreadSafe) {
+ public:
+  ResolverLib() {}
+  virtual ~ResolverLib() {}
+  virtual int ninit(res_state statp) {
+    return ::res_ninit(statp);
+  }
+  virtual void nclose(res_state statp) {
+    return ::res_nclose(statp);
+  }
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ResolverLib);
+};
+
+// Allows mocking FilePathWatcher
+class NET_EXPORT_PRIVATE DnsConfigServicePosix::FilePathWatcherShim :
+    public NON_EXPORTED_BASE(base::NonThreadSafe) {
+ public:
+  FilePathWatcherShim() : watcher_(new base::files::FilePathWatcher()) {}
+  virtual ~FilePathWatcherShim() {}
+
+  virtual bool Watch(
+      const FilePath& path,
+      base::files::FilePathWatcher::Delegate* delegate) WARN_UNUSED_RESULT {
+    return watcher_->Watch(path, delegate);
+  }
+ private:
+  scoped_ptr<base::files::FilePathWatcher> watcher_;
+  DISALLOW_COPY_AND_ASSIGN(FilePathWatcherShim);
+};
+
+class NET_EXPORT_PRIVATE DnsConfigServicePosix::FilePathWatcherFactory :
+    public NON_EXPORTED_BASE(base::NonThreadSafe) {
+ public:
+  FilePathWatcherFactory() {}
+  virtual ~FilePathWatcherFactory() {}
+  virtual FilePathWatcherShim* CreateFilePathWatcher() {
+    return new FilePathWatcherShim();
+  }
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FilePathWatcherFactory);
+};
+
+// Fills in |dns_config| from |res|. Exposed for tests.
+bool NET_EXPORT_PRIVATE ConvertResToConfig(const struct __res_state& res,
+                                           DnsConfig* dns_config);
+
+}  // namespace net
+
+#endif  // NET_DNS_DNS_CONFIG_SERVICE_POSIX_H_