Refactoring and further work on DnsConfigService

- Isolate WatchingFileReader for reusability and testability 
- DnsHosts and ParseHosts to parse /etc/hosts

BUG=90881
TEST=./net_unittests --gtest_filter='DnsConfig*:DnsHosts*:WatchingFileReader*'


Review URL: http://codereview.chromium.org/7826010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@99484 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 56 insertions, 11 deletions

diff --git a/net/dns/dns_config_service.h b/net/dns/dns_config_service.h
index 535dcc1..6ceeaa6 100644
--- a/net/dns/dns_config_service.h
+++ b/net/dns/dns_config_service.h
@@ -6,16 +6,20 @@
 #define NET_DNS_DNS_CONFIG_SERVICE_H_
 #pragma once
 
+#include <map>
 #include <string>
 #include <vector>
 
+#include "base/gtest_prod_util.h"
+#include "base/observer_list.h"
 #include "base/time.h"
+#include "net/base/ip_endpoint.h"  // win requires size of IPEndPoint
 #include "net/base/net_export.h"
+#include "net/dns/dns_hosts.h"
+#include "net/dns/watching_file_reader.h"
 
 namespace net {
 
-class IPEndPoint;
-
 // DnsConfig stores configuration of the system resolver.
 struct NET_EXPORT_PRIVATE DnsConfig {
   DnsConfig();
@@ -23,7 +27,9 @@ struct NET_EXPORT_PRIVATE DnsConfig {
 
   bool Equals(const DnsConfig& d) const;
 
-  bool Valid() const {
+  bool EqualsIgnoreHosts(const DnsConfig& d) const;
+
+  bool IsValid() const {
     return !nameservers.empty();
   }
 
@@ -33,9 +39,12 @@ struct NET_EXPORT_PRIVATE DnsConfig {
   // is less than |ndots|.
   std::vector<std::string> search;
 
+  DnsHosts hosts;
+
   // Resolver options; see man resolv.conf.
   // TODO(szym): use |ndots| and |search| to determine the sequence of FQDNs
   // to query given a specific name.
+  // TODO(szym): implement DNS Devolution for windows
 
   // Minimum number of dots before global resolution precedes |search|.
   int ndots;
@@ -49,9 +58,11 @@ struct NET_EXPORT_PRIVATE DnsConfig {
   bool edns0;
 };
 
+
 // Service for watching when the system DNS settings have changed.
 // Depending on the platform, watches files in /etc/ or win registry.
-class NET_EXPORT_PRIVATE DnsConfigService {
+class NET_EXPORT_PRIVATE DnsConfigService
+  : NON_EXPORTED_BASE(public base::NonThreadSafe) {
  public:
   // Callback interface for the client. The observer is called on the same
   // thread as Watch(). Observer must outlive the service.
@@ -59,30 +70,64 @@ class NET_EXPORT_PRIVATE DnsConfigService {
    public:
     virtual ~Observer() {}
 
-    // Called only when |dns_config| is different from the last check.
+    // Called only when |dns_config| is different from the last call.
     virtual void OnConfigChanged(const DnsConfig& dns_config) = 0;
   };
 
   // Creates the platform-specific DnsConfigService.
   static DnsConfigService* CreateSystemService();
 
-  DnsConfigService() {}
-  virtual ~DnsConfigService() {}
+  DnsConfigService();
+  virtual ~DnsConfigService();
 
   // Immediately starts watching system configuration for changes and attempts
   // to read the configuration. For some platform implementations, the current
   // thread must have an IO loop (for base::files::FilePathWatcher).
-  virtual void Watch() = 0;
+  virtual void Watch() {}
 
   // If a config is available, |observer| will immediately be called with
   // OnConfigChanged.
-  virtual void AddObserver(Observer* observer) = 0;
-  virtual void RemoveObserver(Observer* observer) = 0;
-
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+ protected:
+  FRIEND_TEST_ALL_PREFIXES(DnsConfigServiceTest, NotifyOnChange);
+  friend class DnsHostsReader;
+  // To be called with new config. |config|.hosts is ignored.
+  virtual void OnConfigRead(const DnsConfig& config);
+  // To be called with new hosts. Rest of the config is assumed unchanged.
+  virtual void OnHostsRead(const DnsHosts& hosts);
+
+  DnsConfig dns_config_;
+  // True after first OnConfigRead and OnHostsRead; indicate complete config.
+  bool have_config_;
+  bool have_hosts_;
+
+  ObserverList<Observer> observers_;
  private:
   DISALLOW_COPY_AND_ASSIGN(DnsConfigService);
 };
 
+// A WatchingFileReader that reads a HOSTS file and notifies
+// DnsConfigService::OnHostsRead().
+class DnsHostsReader : public WatchingFileReader {
+ public:
+  explicit DnsHostsReader(DnsConfigService* service);
+
+  virtual void DoRead() OVERRIDE;
+  virtual void OnReadFinished() OVERRIDE;
+
+ private:
+  virtual ~DnsHostsReader();
+
+  DnsConfigService* service_;
+  // Written in DoRead, read in OnReadFinished, no locking necessary.
+  DnsHosts dns_hosts_;
+  bool success_;
+
+  DISALLOW_COPY_AND_ASSIGN(DnsHostsReader);
+};
+
 }  // namespace net
 
 #endif  // NET_DNS_DNS_CONFIG_SERVICE_H_