Implementing chrome://thumbnails page to view URLs in TopSites and cached thumbnails.

chrome/browser/history/top_sites_cache.h

 // 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.
 
 #ifndef CHROME_BROWSER_HISTORY_TOP_SITES_CACHE_H_
 #define CHROME_BROWSER_HISTORY_TOP_SITES_CACHE_H_
 
 #include <map>
 #include <utility>
 
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/history/history_types.h"
 #include "chrome/browser/history/url_utils.h"
 
+class GURL;
+
 namespace history {
 
 // TopSiteCache caches thumbnails for visited pages. Retrieving thumbnails from
 // a given input URL is a two-stage process:
 //
 //   input URL --(map 1)--> canonical URL --(map 2)--> image.
 //
 // (map 1) searches input URL in |canonical_urls_|. canonical URL is
 // assigned to the resulting value if found; else input URL.
 //
@@ skipping 21 matching lines @@
   const URLToImagesMap& images() const { return images_; }
 
   // Returns the thumbnail as an Image for the specified url. This adds an entry
   // for |url| if one has not yet been added.
   Images* GetImage(const GURL& url);
 
   // Fetches the thumbnail for the specified url. Returns true if there is a
   // thumbnail for the specified url. It is possible for a URL to be in TopSites
   // but not have an thumbnail.
   bool GetPageThumbnail(const GURL& url,
-                        scoped_refptr<base::RefCountedMemory>* bytes);
+                        scoped_refptr<base::RefCountedMemory>* bytes) const;
 
   // Fetches the thumbnail score for the specified url. Returns true if
   // there is a thumbnail score for the specified url.
-  bool GetPageThumbnailScore(const GURL& url, ThumbnailScore* score);
+  bool GetPageThumbnailScore(const GURL& url, ThumbnailScore* score) const;
 
   // Returns the canonical URL for |url|.
-  const GURL& GetCanonicalURL(const GURL& url);
+  const GURL& GetCanonicalURL(const GURL& url) const;
 
   // Returns the canonical URL for |url_prefix| that matches by prefix.
-  // Multiple matches exst, returns the canonical URL for the first
+  // If multiple matches exist, returns the canonical URL for the first
   // matching entry under lexicographical order.
-  const GURL& GetCanonicalURLForPrefix(const GURL& url_prefix);
+  const GURL& GetCanonicalURLForPrefix(const GURL& url_prefix) const;
 
   // Returns true if |url| is known.
-  bool IsKnownURL(const GURL& url);
+  bool IsKnownURL(const GURL& url) const;
 
   // Returns the index into |top_sites_| for |url|.
-  size_t GetURLIndex(const GURL& url);
+  size_t GetURLIndex(const GURL& url) const;
 
  private:
   // The entries in CanonicalURLs, see CanonicalURLs for details. The second
   // argument gives the index of the URL into MostVisitedURLs redirects.
   typedef std::pair<MostVisitedURL*, size_t> CanonicalURLEntry;
 
   // Comparator used for CanonicalURLs.
   class CanonicalURLComparator {
    public:
     bool operator()(const CanonicalURLEntry& e1,
@@ skipping 13 matching lines @@
   typedef std::map<CanonicalURLEntry, size_t,
                    CanonicalURLComparator> CanonicalURLs;
 
   // Generates the set of canonical urls from |top_sites_|.
   void GenerateCanonicalURLs();
 
   // Stores a set of redirects. This is used by GenerateCanonicalURLs.
   void StoreRedirectChain(const RedirectList& redirects, size_t destination);
 
   // Returns the iterator into |canonical_urls_| for the |url|.
-  CanonicalURLs::iterator GetCanonicalURLsIterator(const GURL& url);
+  CanonicalURLs::const_iterator GetCanonicalURLsIterator(const GURL& url) const;
 
   // Returns the first iterator into |canonical_urls_| for which |prefix_url|
   // is a URL prefix. Returns |canonical_urls_.end()| if no match is found.
-  CanonicalURLs::iterator GetCanonicalURLsIteratorForPrefix(
-      const GURL& prefix_url);
+  CanonicalURLs::const_iterator GetCanonicalURLsIteratorForPrefix(
+      const GURL& prefix_url) const;
 
   // The top sites.
   MostVisitedURLList top_sites_;
 
   // The images. These map from canonical url to image.
   URLToImagesMap images_;
 
   // Generated from the redirects to and from the most visited pages. See
   // description above typedef for details.
   CanonicalURLs canonical_urls_;
 
   DISALLOW_COPY_AND_ASSIGN(TopSitesCache);
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_CACHE_H_