Add caching to phishing client side detection.

chrome/browser/safe_browsing/client_side_detection_service.h

Index: chrome/browser/safe_browsing/client_side_detection_service.h
diff --git a/chrome/browser/safe_browsing/client_side_detection_service.h b/chrome/browser/safe_browsing/client_side_detection_service.h
index a9bc7f6966ddfb82ccc5d9ce970795b6ddc8ea58..70118b1f81354767a89c47029d66fa9a1c4ac597 100644
--- a/chrome/browser/safe_browsing/client_side_detection_service.h
+++ b/chrome/browser/safe_browsing/client_side_detection_service.h
@@ -25,6 +25,7 @@
 #include "base/callback.h"
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
+#include "base/linked_ptr.h"
 #include "base/platform_file.h"
 #include "base/ref_counted.h"
 #include "base/scoped_callback_factory.h"
@@ -99,9 +100,23 @@ class ClientSideDetectionService : public URLFetcher::Delegate {
     ERROR_STATUS,
   };
 
+  // CacheState holds all information necessary to respond to a caller without
+  // actually making a HTTP request.
+  struct CacheState {
+    bool is_phishing;
+    base::Time timestamp;
+
+    CacheState(bool phish, base::Time time)
+        : is_phishing(phish),
+          timestamp(time) {}

[Brian Ryner, 2011/02/08 20:16:48]

The style guidelines discourage inlining constructors unless it's necessary:
http://www.chromium.org/developers/coding-style#TOC-Inline-functions

[gcasto (DO NOT USE), 2011/02/09 00:10:52]

Moved.

+  };
+  typedef std::map<GURL, linked_ptr<CacheState> > PhishingCache;
+
   static const char kClientReportPhishingUrl[];
   static const char kClientModelUrl[];
   static const int kMaxReportsPerDay;
+  static const base::TimeDelta kNegativeCacheInterval;
+  static const base::TimeDelta kPositiveCacheInterval;
 
   // Use Create() method to create an instance of this object.
   ClientSideDetectionService(const FilePath& model_path,
@@ -165,6 +180,12 @@ class ClientSideDetectionService : public URLFetcher::Delegate {
                              const ResponseCookies& cookies,
                              const std::string& data);
 
+  // Returns true and sets is_phishing if url is in the cache and valid.
+  bool GetCachedResult(GURL url, bool* is_phishing);

[Brian Ryner, 2011/02/08 20:16:48]

Have this take a const GURL&, so that it doesn't need to make an extra copy of
the URL?

[gcasto (DO NOT USE), 2011/02/09 00:10:52]

Done.

+
+  // Invalidate cache results which are no longer useful.
+  void UpdateCache();
+
   // Get the number of phishing reports that we have sent over the last 24
   // hours.
   int GetNumReportsPerDay();
@@ -181,6 +202,12 @@ class ClientSideDetectionService : public URLFetcher::Delegate {
   struct ClientReportInfo;
   std::map<const URLFetcher*, ClientReportInfo*> client_phishing_reports_;
 
+  // Cache of completed requests. Used to satisfy requests for the same urls
+  // as long as the next request falls within our caching window (which is
+  // determined by kNegativeCacheInterval and kPositiveCacheInterval).
+  // TODO(gcasto): Serialize this so that it doesn't reset on browser restart.
+  PhishingCache cache_;
+
   // Timestamp of when we sent a phishing request. Used to limit the number
   // of phishing requests that we send in a day.
   // TODO(gcasto): Serialize this so that it doesn't reset on browser restart.