Implementing URL prefix match for history thumbnail cache.

chrome/browser/history/top_sites_cache.cc

 // Copyright (c) 2012 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/history/top_sites_cache.h"
 
 #include "base/logging.h"
 #include "base/memory/ref_counted_memory.h"
 
 namespace history {
@@ skipping 37 matching lines @@
   std::map<GURL, Images>::const_iterator found =
       images_.find(GetCanonicalURL(url));
   if (found != images_.end()) {
     *score = found->second.thumbnail_score;
     return true;
   }
   return false;
 }
 
 const GURL& TopSitesCache::GetCanonicalURL(const GURL& url) {
-  CanonicalURLs::iterator i = TopSitesCache::GetCanonicalURLsIterator(url);
+  CanonicalURLs::iterator i = GetCanonicalURLsIterator(url);
   return i == canonical_urls_.end() ? url : i->first.first->url;
 }
 
+const GURL& TopSitesCache::GetCanonicalURLForPrefix(const GURL& url) {
+  CanonicalURLs::iterator i = GetCanonicalURLsIteratorForPrefix(url);
+  return i == canonical_urls_.end() ? url : i->first.first->url;
+}
+
 bool TopSitesCache::IsKnownURL(const GURL& url) {
   return GetCanonicalURLsIterator(url) != canonical_urls_.end();
 }
 
 size_t TopSitesCache::GetURLIndex(const GURL& url) {
   DCHECK(IsKnownURL(url));
   return GetCanonicalURLsIterator(url)->second;
 }
 
 void TopSitesCache::GenerateCanonicalURLs() {
   canonical_urls_.clear();
   for (size_t i = 0; i < top_sites_.size(); i++)
     StoreRedirectChain(top_sites_[i].redirects, i);
 }
 
 void TopSitesCache::StoreRedirectChain(const RedirectList& redirects,
                                        size_t destination) {
-  // redirects is empty if the user pinned a site and there are not enough top
+  // |redirects| is empty if the user pinned a site and there are not enough top
   // sites before the pinned site.
 
   // Map all the redirected URLs to the destination.
   for (size_t i = 0; i < redirects.size(); i++) {
     // If this redirect is already known, don't replace it with a new one.
     if (!IsKnownURL(redirects[i])) {
       CanonicalURLEntry entry;
       entry.first = &(top_sites_[destination]);
       entry.second = i;
       canonical_urls_[entry] = destination;
     }
   }
 }
 
 TopSitesCache::CanonicalURLs::iterator TopSitesCache::GetCanonicalURLsIterator(
     const GURL& url) {
   MostVisitedURL most_visited_url;
   most_visited_url.redirects.push_back(url);
   CanonicalURLEntry entry;
   entry.first = &most_visited_url;
   entry.second = 0u;
   return canonical_urls_.find(entry);
 }
 
+TopSitesCache::CanonicalURLs::iterator
+    TopSitesCache::GetCanonicalURLsIteratorForPrefix(const GURL& prefix_url) {
+  MostVisitedURL most_visited_url;
+  most_visited_url.redirects.push_back(prefix_url);
+  CanonicalURLEntry entry;
+  entry.first = &most_visited_url;
+  entry.second = 0u;
+
+  // Perform effective binary search for URL prefix search.
+  TopSitesCache::CanonicalURLs::iterator it =
+      canonical_urls_.lower_bound(entry);
+  // Perform prefix match.
+  if (it != canonical_urls_.end()) {
+    const GURL& comp_url = it->first.first->redirects[it->first.second];
+    if (!UrlIsPrefix(prefix_url, comp_url))
+      it = canonical_urls_.end();
+  }
+  return it;
+}
+
 }  // namespace history